KR100791907B1 - Polishing device - Google Patents

Abstract

As a method for manufacturing and polishing a semiconductor element, and as a polishing apparatus, the initial unevenness of the metal film can be easily flattened, the extra metal film removal efficiency is excellent, and when the metal film is planarized by polishing, it is applied to the interlayer insulator under the metal film. Damage to the body can be suppressed. This method includes a step of interposing an electrolyte solution containing a chelating agent between the cathode member and the copper film, and applying a voltage between the cathode member as the cathode and the copper film as the anode to oxidize the surface of the copper film and form a chelated film of oxidized copper. And removing the projections of the chelated film corresponding to the shape of the copper film and exposing the projections of the copper film on its surface, wherein the chelate film forming process and the chelated film removal are performed until the projections of the copper film are flattened. Repeat the process.

Electrolytic power supply, shaft driver, table driver, controller, control panel, slurry supply part, electrolyte supply part, semiconductor substrate, interlayer insulating film, barrier film, seed film, copper film, chelate film, cathode member, cathode electrode, anode electrode, surface plate, polishing Pad, insulator

Description

Polishing device {POLISHING APPARATUS}

1 (A) to 1 (C) are cross-sectional views showing the manufacturing process of the semiconductor manufacturing method of the present invention, where 1 (A) is an insulating film formation process on a semiconductor substrate, and 1 (B) is a contact hole and a wiring groove. 1 (C) shows up to the formation process of the barrier film.

2 (D) and 2 (E) show a process following FIG. 1 (A) and 1 (C), 2 (D) until a formation process of a copper film as a seed film, and 2 (E) formation of a copper film The process up to is shown.

3 (F) and 3 (G) show a process subsequent to FIGS. 2 (D) and 2 (E), FIG. 3 (F) until the anodic oxidation process of the copper film, and FIG. 3 (G) shows the formation of a chelate film. The process up to is shown.

4 (H) and 4 (I) show a process following FIG. 3 (F) and 3 (G), and FIG. 4 (H) shows the process of removing the chelating film of the convex portion, and FIG. 4 (I) shows the The remodeling process is shown.

Figures 5 (J) to 5 (L) show a process subsequent to Figures 4 (H) and 4 (I), Figure 5 (J) until the planarization process of the copper film, and Figure 5 (K) spares the copper film. 5 (L) shows up to the removing step of the barrier film.

6 is a block diagram of the polishing apparatus according to the present embodiment.

7 is an enlarged view of an internal structure of the abrasive tool supporter in the polishing apparatus according to the present embodiment.

FIG. 8A is a bottom view of the electrode plate used in the polishing apparatus according to the present embodiment, and FIG. 8B is an enlarged view of the vicinity of the electrode plate.

9 is a positional relationship diagram between the polishing tool and the wafer.

10 is a cross-sectional view for explaining electropolishing of the polishing apparatus according to the present invention.

FIG. 11 is an enlarged cross-sectional view of the circle C of FIG. 10.

FIG. 12 is an enlarged cross-sectional view of the circle D of FIG. 11.

13 is a view of a first modification of the polishing apparatus according to the present invention.

14 is a view of a second modification of the polishing apparatus according to the present invention.

FIG. 15 is a view of a third modified example of the conventional CMP apparatus of the polishing apparatus according to the present invention. FIG.

FIG. 16 is an explanatory diagram for an electrolytic composite polishing operation in the polishing apparatus shown in FIG. 15.

17 is an exemplary view of another example of the electrode configuration of the polishing pad.

18 is an illustration of another example of the electrode configuration of the polishing pad.

19 is a schematic configuration diagram of a polishing apparatus according to a second embodiment of the present invention.

20 is a schematic configuration diagram of a polishing apparatus according to a third embodiment of the present invention.

21 is a configuration diagram of a polishing apparatus according to the fourth embodiment of the present invention.

It is explanatory drawing about 5th Embodiment of this invention.

It is explanatory drawing about 6th Embodiment of this invention.

24 is an explanatory diagram of a seventh embodiment of the present invention.

25 (A) to 25 (C) are cross-sectional views showing the manufacturing process of the formation method in the copper wiring by the dual damascene method according to the prior art, and FIG. 25 (A) is a process of forming the interlayer insulating film. B) shows the process of forming the wiring groove and the contact hole, and FIG. 25C shows the process of forming the barrier film.

26 (D) and 26 (F) show processes subsequent to FIGS. 25A to 25C, and FIG. 26D shows the seed film forming process and 26F shows the wiring forming process. Illustrated.

It is sectional drawing for demonstrating the dishing which arises in the copper film polishing process by CMP method.

It is sectional drawing for demonstrating the erosion which arises in the copper film grinding | polishing process by a CMP method.

It is sectional drawing for demonstrating the recess which arises in the copper film polishing process by CMP method.

It is sectional drawing for demonstrating the scratch and chemical damage which generate | occur | produce in the copper film polishing process by CMP method.

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for manufacturing and polishing a semiconductor device, and more particularly, to a method for manufacturing and polishing a semiconductor device including a step of reducing surface irregularities accompanying the formation of a metal film.

Along with high integration and miniaturization of semiconductor devices, finer wirings, smaller wiring pitches, and multilayered wirings are in progress, and the importance of multilayer wiring technology in semiconductor device manufacturing processes is increasing.

On the other hand, aluminum has been widely used as a wiring material of a multilayer wiring structure semiconductor device. In recent years, in order to suppress signal propagation delay in a design rule of 0.25 μm or less, wiring material is replaced with aluminum from copper. The development of the process is booming. When copper is used as the wiring, there is an advantage that both low resistance and high electromigration tolerance can be achieved.

In the process of using this copper for wiring, for example, metal is buried in a groove-shaped wiring pattern previously formed in an interlayer insulating film, and an excess metal film is removed by a chemical mechanical polishing (CMP) method. The wiring process called the damascene method of forming a wiring is becoming prominent. This damascene method eliminates the need for etching the wiring and has the advantage that the process can be simplified because the interlayer insulating film of the conflict also becomes flat by itself.

In addition, not only wiring grooves but also contact holes are formed in the interlayer insulating film, and the dual damascene method in which both the wiring grooves and the contact holes are buried in metal at the same time allows for a larger reduction in the wiring process. Do.

Here, an example of the copper wiring formation process by said dual damascene method is demonstrated with reference to the following figure.

First, as shown in Fig. 24A, for example, an interlayer insulating film formed of, for example, silicon oxide on a semiconductor substrate 301, such as silicon, on which an impurity diffusion region (not shown) is formed. 302 is formed by, for example, a reduced pressure chemical vapor deposition (CVD) method.

Subsequently, as shown in FIG. 24B, a predetermined pattern of wirings electrically connected to the contact hole CH leading to the impurity diffusion region of the semiconductor substrate 301 and the impurity diffusion region of the semiconductor substrate 301. The grooves M to be formed are formed using a known photolithography technique and an etching technique.

Subsequently, as shown in FIG. 24C, a barrier film 305 is formed in the surface, the contact hole CH and the groove M of the interlayer insulating film 302. The barrier film 305 is formed of, for example, a material such as Ta, Ti, TaN, TiN by a known sputtering method. The barrier film 305 is made of copper, and when the interlayer insulating film 302 is made of silicon oxide, the copper has a large diffusion coefficient to silicon oxide, which is easy to oxidize, thereby preventing this. To be installed.

Next, as shown in FIG. 25D, copper is deposited on the barrier film 305 to a predetermined film thickness by a known spatter method to form a seed film 306.

Next, as shown in FIG. 25E, the copper film 307 is formed so that the contact holes CH and the grooves M are buried in copper. The copper film 307 is formed by, for example, a plating method, a CVD method, a spatter method, or the like.

Subsequently, as shown in Fig. 25F, the extra copper film 307 and the barrier film 305 on the interlayer insulating film 302 are removed and planarized by the CMP method. By the above process, copper wiring and contacts 309 are formed.

By repeating the above process on the wiring 308, a multilayer wiring can be formed.

However, in the copper wiring forming process using the dual damascene method, a predetermined pressure is applied between the polishing tool and the copper film in the planarization technique using the conventional CMP method in the process of removing the extra copper film 307 by the CMP method. Since the damage to the semiconductor substrate is large, especially when a low dielectric constant organic insulating film having a low mechanical strength is adopted as the interlayer insulating film, the damage cannot be ignored and cracks in the interlayer insulating film are generated. There is a problem such as peeling of the interlayer insulating film from the substrate.

In addition, since the removal performance of the interlayer insulating film 302, the copper film 307, and the barrier film 305 is different, dishing, erosion, thinning, recesses, etc., are formed in the wiring 308. There was a problem that it was easy to occur.

As shown in Fig. 26, in the design rule of 0.18 mu m rule, for example, when there is a wide wiring 308 of about 100 mu m, the center portion of the wiring is excessively removed. There is a dent, and if this dishing occurs, the cross-sectional area of the wiring 308 is insufficient, which causes a poor wiring resistance value. This dishing is likely to occur when relatively soft copper or aluminum is used for the wiring material.

As shown in Fig. 27, the erosion is a phenomenon in which a portion having a high pattern density, in which a wiring having a width of 1.0 µm is formed at a density of 50 percent in a range of 3000 µm, is removed excessively. If this occurs, the cross-sectional area of the wiring is insufficient, resulting in poor wiring resistance value.

As shown in FIG. 28, the recess is a phenomenon in which the wiring 308 is lowered at the boundary between the interlayer insulating film 302 and the wiring 308, resulting in a step difference. In this case, since the cross-sectional area of the wiring is insufficient, the wiring resistance value It may cause defects.

On the other hand, in the step of planarizing and removing the extra copper film 307 by the CMP method, since the copper film needs to be removed efficiently, the polishing rate which is the removal amount per unit time is, for example, 500 nm / min or more. Is required.

In order to improve this polishing rate, it is necessary to increase the processing pressure on the wafer, and when the processing pressure is increased, scratches (SC) or chemical damage (CD) may occur on the wiring surface as shown in FIG. It is easy, especially in soft copper. For this reason, it is a cause of trouble such as wiring open, short, poor wiring resistance value, and the disadvantage that the scratch, interlayer insulating film 302 peeling, dishing, erosion, and the generation amount of the scratches also increase when the processing pressure is increased. This existed.

The present invention has been made in view of the above problems, and accordingly, the present invention can easily planarize initial unevenness when polishing a copper film of a semiconductor device having a copper wiring by polishing, and is also excellent in extra copper film removal efficiency. An object of the present invention is to provide a polishing apparatus and a polishing method capable of suppressing damage to an interlayer insulating film or the like under a copper film.

In order to achieve the above object, a method of manufacturing a semiconductor device according to the present invention includes the steps of forming a wiring groove in an insulating film formed on a substrate, and a step of the wiring groove on the entire surface of the insulating film to bury the wiring groove. Depositing a copper film having a concave-convex shape on the surface, and applying a voltage between the negative electrode member and the copper film with an electrolyte solution containing a chelating agent, and using the negative electrode member as the negative electrode and the copper film as the positive electrode. To oxidize the surface of the copper film and to form a chelate film of the oxidized copper; and selectively remove the convex portions of the chelate film due to the unevenness of the copper film. The chelate film removal process of exposing the copper film of a part to a surface, and the convex part of the said copper film is planarized. And it repeats the above chelating film forming step and the chelating film removing process till then.

According to the manufacturing method of the semiconductor manufacturing apparatus which concerns on the said invention, when the groove | channel for wiring is buried by a copper film, the formed uneven copper film surface is anodized, and this anodized copper is made to chelating agent in electrolyte solution. Chelated to form a chelate film having a very low mechanical strength that can be easily removed. When the convex portion of the chelate film is removed, the exposed copper is chelated after anodization, so that the flatness of the copper film is achieved by repeating the removal of this chelate film convex portion.

Since the resistance of the chelating film is higher than that of copper, the copper covered by the chelating film that is not removed and remains is difficult to anodic oxidation by energization, so that the progress of chelation is very delayed, and the formation of the chelating film by anodic oxidation is only possible. This is done in the convex portion of the copper film exposed by the removal of the chelate film.

In addition, when the potential difference between the copper film as the anode and the cathode member as the cathode is constant because the current flows through the electrolyte, the shorter the distance between the electrodes increases the current density, so that the copper of the convex portion is removed from the exposed copper film with the chelate film removed. Since the distance between the electrodes and the cathode member as the cathode is short, the current density is increased, and as a result, the anodic oxidation rate is increased, thereby promoting chelation.

Therefore, the chelation of the convex part copper film is accelerated, so that efficient planarization and damage to the interlayer insulating film under the copper film can be suppressed.

The semiconductor device manufacturing method of the present invention preferably further has a step of removing the chelate film formed on the surface of the copper film until the convex portion of the copper film is flattened until the copper film deposited on the outside of the wiring groove is removed.

Thereby, damage to the interlayer insulation film etc. of a lower copper film layer can be suppressed, and copper wiring can be formed.

In the method of manufacturing a semiconductor device of the present invention, preferably, in the step of applying a voltage using the negative electrode member as a negative electrode, a voltage is applied using a conductive polishing tool having a conductivity as a negative electrode used for removing the chelated film convex portion. This makes it possible to efficiently chelate the copper film by anodic oxidation and to remove the chelate film by using the polishing tool for the cathode.

In the method of manufacturing a semiconductor device of the present invention, preferably, in a step of applying a voltage with the copper film as an anode, an anode member contacting or approaching the copper film is used as an anode, and the copper film is used as an anode through the electrolyte solution.

By supplying current to the copper film locally through the electrolyte by the anode member, stable current supply is possible.

In this case, the copper film is energized from the positive electrode member through the electrolytic solution, and again from the copper film to the negative electrode member via the electrolytic solution, whereby the copper film in the vicinity of the negative electrode member is anodized to chelate.

In the method of manufacturing a semiconductor device of the present invention, preferably, in the step of applying a voltage using the cathode member as a cathode, a voltage is applied using a conductive electrode plate disposed in parallel with the copper film as a cathode.

By arranging the electrode plates in parallel, as described above, in the exposed copper film, the convex portion has a shorter inter-electrode distance, so that the rate of anodic oxidation is increased by increasing the current density, thereby facilitating efficient flattening. Can be achieved.

The semiconductor device manufacturing method of the present invention is preferably removed by wiping or mechanical polishing in the chelate film removal step.

Since the chelate film has a very low mechanical strength, it is unnecessary to mechanically grind by strong pressure, and can be easily removed by wiping or mechanical grind by low pressure.

The semiconductor device manufacturing method of the present invention is preferably removed by applying vibration to the substrate in the chelate film removal step. Also preferably, the chelate membrane is removed by flowing the electrolyte in the chelate membrane removal step.

Since the chelate film has a very low mechanical strength, it can be easily removed not only by mechanical polishing but also by vibration and flow action of the electrolyte solution.

In the method of manufacturing a semiconductor device of the present invention, preferably, the current flowing through the cathode member and the copper film in the chelate film forming step and the chelate film removing step is monitored and the copper film is polished based on the magnitude of the current value. Manage your progress.

For example, by using a chelating agent whose electrical resistance of the resulting chelate film is larger than that of the copper film, the current flowing between the cathode member and the copper film is exposed to copper when the chelate film of the convex portion is removed before the convex portion of the copper film is flattened. Therefore, the current value increases, and when the chelate film is formed on the exposed copper again, the current value decreases, and when the copper film is flattened, the entire copper film surface is exposed by removing the entire surface of the chelate film on the copper film. Therefore, the current value takes the maximum once and then the current value has the maximum each time it is removed.

When the barrier film is exposed, since the resistance of the barrier film is generally larger than that of copper, the current value after the removal of the chelating film starts to fall from the maximum value. Formation of the chelate film by the subsequent anodic oxidation can be stopped, and progress of polishing can be managed.

Moreover, in order to achieve the said objective, the grinding | polishing apparatus of this invention is a grinding | polishing apparatus which grinds the to-be-polished object which has a copper film on a to-be-polished surface, The electroconductive polishing tool which has a polishing surface, and the said grinding | polishing tool have a predetermined rotating shaft. Rotating tool means for rotating and supporting the polishing tool, moving and positioning means for moving and positioning the polishing tool in a direction substantially perpendicular to the surface to be polished of the object to be polished, and the surface to be polished Relative moving means for relatively moving the polishing surface along a predetermined plane, electrolyte supply means for supplying an electrolyte solution containing a chelating agent to the surface to be polished, the polishing surface as an anode, and the polishing tool as a cathode. And current supply means for supplying a current flowing from the surface to be polished to the polishing tool through the electrolyte solution.

According to the polishing apparatus of the present invention, in the case where a copper film having irregularities is formed on the surface to be polished, for example, the surface of the surface of the copper film to be polished is anodized by current supply means, This anodized copper is chelated by a chelating agent in the electrolyte solution supplied by the electrolyte supply means, thereby forming a chelate film having a very low mechanical strength that can be easily removed.

By the moving positioning means, the polishing surface is brought into contact with or near to the surface to be polished, and the polishing surface and the polishing surface are rotated by the polishing tool rotation support means and the rotation support means, respectively, in a state of contacting or approaching the surface of the chelate film. By removing the convex portion and polishing the chelated film convex portion of the entire surface to be polished by the relative moving means, the object to be polished can be efficiently polished at a low polishing pressure.

In the polishing apparatus of the present invention, preferably, the current supply means is arranged in contact with or accessible to the surface to be polished, the anode member for energizing the polishing surface as an anode, the anode member and the polishing surface. A direct current power source for applying a predetermined voltage between the tools is provided.

By supplying current to the copper film locally through the electrolyte by the anode member, stable current supply can be achieved.

 In this case, electricity is supplied from the anode member to the surface to be polished through the electrolyte solution, and again from the polishing surface to the polishing tool through the electrolyte solution, whereby the copper film near the polishing tool serving as the cathode is anodized to chelate.

For example, by making the pulse width very short, the amount of chelate film produced by anodic oxidation per pulse is extremely small, and discharges due to sudden changes in the distance between electrodes, such as when contact with the surface irregularities, bubbles or particles are interposed. It is effective because it prevents accidental or huge anodic oxidation of the copper film, such as spark discharge due to sudden change in electrical resistance, which occurs in some cases, and because small things are continuously performed.

In the polishing apparatus of the present invention, preferably, the anode member is made of a noble metal as compared with copper formed on the surface to be polished. As a result, it is possible to prevent elution or the like of the positive electrode member into the electrolytic solution and to positively anodize the copper film. In addition, since the anode does not elute, there is no need to consider the poppy.

The polishing apparatus of the present invention preferably includes current detecting means for detecting a current value flowing from the polished surface to the polishing tool. More preferably, on the basis of the detection signal from the current detecting means, control means for controlling the position in a direction substantially perpendicular to the to-be-polished surface of the polishing tool such that the current value is constant.

By controlling the current value constantly, the current density is always constant, and the amount of chelate film generated by anodic oxidation can also be constantly controlled.

Moreover, in order to achieve the said objective, the grinding | polishing apparatus of this invention is equipped with the grinding | polishing tool which has the grinding | polishing surface which contacts rotationally on the whole surface of the to-be-polished object which has a copper film on a to-be-polished surface, A polishing apparatus for flattening polishing by bringing a polishing object into contact with the polishing surface while rotating the polishing object, the polishing apparatus comprising electrolyte supply means for supplying an electrolyte solution containing a chelating agent to the polishing surface, and having an anode electrode and a cathode electrode that are capable of supplying electricity to the polishing surface. Then, the surface to be polished is planarized by electrolytic polishing which combines electropolishing with the electrolytic solution and mechanical polishing with the polishing surface.

According to the polishing apparatus of the present invention, for example, by applying a voltage to the anode and the cathode provided on the polishing surface, it is energized from the anode of the polishing surface to the copper film of the surface to be polished through the electrolyte solution, and the electrolyte solution from the copper film again. By energizing the cathode of the polishing surface through the anode, the copper film on the surface to be polished near the cathode is anodized.

The anodic oxidized copper is chelated by a chelating agent in the electrolyte solution supplied by the electrolyte supply means to form a chelate film having a very low mechanical strength that can be easily removed.

By rotating the polished surface and the whole surface of the to-be-polished surface, respectively, in the contact or approaching state, the convex part of a chelating film is removed from the whole to-be-polished surface, and a to-be-polished object can be polished efficiently at low pressure.

Moreover, in order to achieve the said objective, the grinding | polishing apparatus of this invention provides the support means which supports a to-be-polished object, the electrode plate arrange | positioned in parallel with the to-be-polished surface, and the vibration to apply | stimulate the to-be-polished object Vi) means, an electrolyte supply means for supplying an electrolyte solution containing a chelating agent between the surface to be polished and the electrode plate, the surface to be polished as an anode, and the electrode plate as a cathode; Electrolytic current supply means for supplying an electrolytic current flowing through the electrolyte to the electrode plate.

According to the polishing apparatus of the present invention, in the case where a copper film having irregularities is formed on the surface to be polished, for example, the surface of the surface of the copper film to be polished is anodized by an electrolytic current supply means. This anodized copper is chelated by a chelating agent in the electrolyte solution supplied by the electrolyte supply means, thereby forming a chelate film having a very low mechanical strength that can be easily removed.

The convex portion of the chelate film is selectively removed by vibrating action on the object to be polished by the excitation means, thereby achieving efficient polishing with less damage to the object to be polished.

The polishing apparatus of the present invention preferably includes current detecting means for detecting an electrolytic current value flowing from the surface to be polished to the electrode plate. As a result, by monitoring the electrolytic current, the polishing process can be managed, and the progress of the polishing process can be accurately understood.

Moreover, in order to achieve the said objective, the grinding | polishing apparatus of this invention is a grinding | polishing apparatus which grinds the to-be-polished object which has a copper film on a to-be-polished surface, Comprising: Support means for supporting a to-be-polished object, Arranged in parallel with the to-be-polished surface The electrode plate, an electrolyte supply means for supplying an electrolyte solution containing a chelating agent between the surface to be polished and the electrode plate, the surface to be polished as an anode, and the electrode plate as a cathode. Electrolytic current supply means for supplying an electrolytic current flowing through the electrolyte to the electrode plate, and flow means for flowing the electrolyte between the surface to be polished and the electrode plate.

According to the polishing apparatus of the present invention, in the case where a copper film having irregularities is formed on the surface to be polished, for example, the surface of the surface of the copper film to be polished is anodized by an electrolytic current supply means. This anodized copper is chelated by a chelating agent in the electrolyte solution supplied by the electrolyte supply means, thereby forming a chelate film having a very low mechanical strength that can be easily removed.

The convex portion of the chelate membrane is selectively removed by the flow action of the electrolyte solution to the chelate membrane of the object to be polished by the flow means, thereby achieving efficient polishing with little damage to the object to be polished.

The polishing apparatus of the present invention preferably includes current detecting means for detecting an electrolytic current value flowing from the surface to be polished to the electrode plate. As a result, by monitoring the electrolytic current, the polishing process can be managed, and the progress of the polishing process can be accurately understood.

Moreover, in order to achieve the said objective, the grinding | polishing method of this invention is a grinding | polishing method of the to-be-polished object which has a copper film in a to-be-polished surface, The said negative electrode is interposed between the negative electrode member and the to-be-polished surface, and the electrolyte solution containing a chelating agent is provided. A chelate film forming step of applying a voltage by oxidizing the surface of the copper film and forming a chelated film of the oxidized copper by applying a voltage using the member as a cathode and the surface to be polished of the object to be polished as an anode, and the surface shape of the copper film. The chelating film removal step of selectively removing the convex portion of the chelate film according to the present invention and exposing the copper film of the convex portion to the surface, and the chelate film forming step and the chelate film removing step until the convex portion of the copper film is flattened. Repeat.

According to the polishing method of the present invention, a voltage is applied between the negative electrode member and the surface to be polished by applying an electrolyte solution having a chelating agent, and the voltage is applied by using the negative electrode member as the cathode and the surface to be polished as the anode. For example, the surface of the uneven copper film is anodized, and the anodized copper is chelated by a chelating agent in the electrolyte, thereby forming a chelate film having a very low mechanical strength that can be easily removed.

If the convex portion of this chelate film is selectively removed, the exposed copper is chelated after anodization, so that the flatness of the copper film is achieved by repeating the selective removal of this chelate film convex portion.

Since the resistance of the chelating film is higher than that of copper, the copper covered by the chelating film that is not removed and remains is difficult to anodic oxidation by energization, so that the progress of chelation is very delayed, and the formation of the chelating film by anodic oxidation is only possible. This is done in the convex portion of the copper film exposed by the removal of the chelate film.

In addition, when the potential difference between the copper film of the positive electrode and the negative electrode member of the negative electrode is constant because the current flows through the electrolyte, the shorter the distance between the electrodes increases the current density, so that the chelated film is removed and the copper of the convex portion is exposed. Since the film side has a short distance between the negative electrode member and the electrode as the negative electrode, the current density becomes large, and as a result, the anodic oxidation rate is increased and the chelation is promoted.

Therefore, the chelation of the convex part copper film is accelerated, so that efficient planarization and damage to the interlayer insulating film under the copper film can be suppressed.

The polishing method of the present invention is preferably removed by applying vibration to the object to be polished in the chelate film removal step. Also preferably, in the chelate film removing step, the liquid is removed by applying flow to the electrolyte solution in contact with the object to be polished.

Since the chelate film has a very low mechanical strength, it can be easily removed not only by mechanical polishing but also by vibration and flow action of the electrolyte solution.

EMBODIMENT OF THE INVENTION Below, embodiment of the manufacturing method, the grinding | polishing apparatus, and the grinding | polishing method of this invention are demonstrated with reference to drawings.

EMBODIMENT OF THE INVENTION Embodiment of the grinding | polishing method of this invention is demonstrated about the case where it applies to the copper wiring formation process by the dual damascene method of the semiconductor element which has copper wiring.

First, as shown in Fig. 1 (a), for example, on a semiconducting substrate 101 such as silicon, for example, as an oxide of The formed interlayer insulating film 102 is formed by, for example, a reduced pressure chemical vapor deposition (CVD) method using tetra ethyl ortho silicate (TEOS).

Subsequently, as shown in Fig. 1 (b), contact holes and wiring grooves leading to the impurity diffusion region of the semiconductor substrate 101 are formed using, for example, known photolithography and etching techniques. In addition, the depth of the groove | channel for wiring shall be about 800 nm, for example.

Subsequently, as shown in FIG. 1C, a barrier film 103 is formed in the surface, contact holes and grooves of the interlayer insulating film 102. For example, the barrier film 103 may be formed of a material such as Ta, Ti, W, Co, TaN, TiN, Wn, CoW, or CoWP in a PVD (Physical Vapor Deposion) method using a sputtering apparatus, a vacuum deposition apparatus, or the like. For example, it forms in the film thickness of about 25 nm.

The barrier film 103 is provided to prevent the material constituting the wiring from diffusing into the interlayer insulating film 102 and to improve the adhesion with the interlayer insulating film 102. In particular, in the case where the wiring material is copper and the interlayer insulating film 102 is silicon oxide as in the present embodiment, copper is required to prevent this because the diffusion coefficient to silicon oxide is large and easily oxidized.

Subsequently, as shown in FIG. 2 (d), a seed film 104 made of copper of the same material as the wiring forming material on the barrier film 103 is formed by a known spatter method, for example, a film of about 150 nm. Form to thickness. The seed film 104 is formed to promote the growth of metal grains when the metal is buried in the wiring grooves and contact holes.

Subsequently, as shown in FIG. 2E, the wiring layer 105 made of Al, W, WN, Cu, Au, Ag, or an alloy thereof is placed in the barrier film 103 so as to bury the contact holes and the wiring grooves. For example, it is formed in the film thickness of about 1600 nm. The wiring layer 105 is preferably formed by an electrolytic plating method or an electroless plating method, but may be formed by a CVD method, a spatter method, or the like. The seed film 104 is integrated with the wiring layer 105.

On the surface of the wiring layer 105, unevenness, for example, about 800 nm high, which is formed by the buried contact holes and the wiring grooves, is formed.

Although the above process is performed by the process similar to the conventional one, in the process of this invention, the removal of the excess wiring layer 105 which exists in the interlayer insulation film 102 is performed by electrolytic compound polishing using electrolytic action instead of chemical mechanical polishing. . Specifically, the copper film 105 is anodized by an electrolytic action and a chelate film 106 is formed on the surface.

As shown in FIG. 3 (f), the method of forming the chelating film 106 includes disposing the cathode member 120 in parallel with the copper film 105 and including an electrolytic solution (EL) containing a chelating agent that chelates copper. ) Is interposed between the cathode member 120 and the copper film 105. In addition, after FIG. 4, description of the negative electrode member 120 and electrolyte EL is abbreviate | omitted in the figure.

Here, as a chelating agent, for example, quinaldine acid of chemical formula (1), glycine of chemical formula (2), citlic acid of chemical formula (3), chemical formula (4) Oxalic acid), propionic acid of the chemical formula (5), and the like.

Subsequently, voltage is applied using the cathode member 120 as the cathode and the copper film 105 and the barrier film 103 as the anode.

[Tue 1]

               (One)

[Tue 2]

NH ₂ CH ₂ COOH (2)

[Tue 3]

          (3)

[Tue 4]

(COOH) ₂ (4)

[Tue 5]

C ₂ H ₅ COOH (5)

The copper film 105 as an anode is anodized to form CuO. The distance d1 between the convex portion on the surface of the copper film 105 and the cathode member 120 is shorter than the distance d2 between the concave portion on the surface of the copper film 105 and the cathode member 120. When the potential difference between 120 and the copper film 105 is constant, the anodic oxidation is promoted because the current density of the convex portion becomes larger than that of the concave portion.

As shown in Fig. 3G, the surface of the anodized copper film 105 (CuO) is chelated by a chelating agent in the electrolytic solution. When chelating agent is used, it is a film formed of the chelate compound of the chemical formula (6), and when glycine is used, the film is formed of the chelate compound of the chemical formula (7). The electrical resistance is higher than that of copper and the mechanical strength is very low, therefore, after the chelating film 106 is formed on the surface of the copper film 105, the cathode member is formed from the copper film 105 through the electrolytic solution EL. The current value flowing to 120 decreases, before the anodization, the chelation of copper is in a suppressed state.

[Tue 6]

[Tue 7]

        (6), (7)

Subsequently, as shown in Fig. 4H, the convex portions of the chelated film 106 formed on the surface of the copper film 105 are selectively removed by wiping and mechanical polishing. In addition, when removing the convex part of the chelate film 106 by mechanical polishing, although not shown previously, you may contain a slurry in electrolyte solution EL. In addition, since the mechanical strength of the chelate film 106 is very low, the chelate film 106 can be easily removed by applying vibration to the substrate 101 or by applying flow to the electrolyte EL.

At this time, since the convex portions of the copper film 105 with small electrical resistance are exposed in the electrolyte solution, the current value flowing from the copper film 105 through the electrolyte solution EL to the cathode member 120 increases.

Subsequently, as shown in FIG. 4 (i), the convex portions of the copper film 105 exposed in the electrolyte are concentrated anodized due to the low electrical resistance and the short distance from the negative electrode member 120. Anodized copper is chelated. At this time, the current value flowing from the copper film 105 to the cathode member 120 through the electrolytic solution EL decreases again.

Thereafter, the convex portion of the chelate film 106 is selectively removed by the above-described wiping, mechanical polishing or the like, and the exposed copper film 105 is intensively anodized and chelated, so that the convex portion of the chelate film 106 is concentrated. The process of removing selectively is repeated. At this time, the current value flowing from the copper film 105 to the cathode current through the electrolytic solution EL increases simultaneously with the removal of the chelate film 106, and the state of decreasing simultaneously with the formation of the chelate film 106 is repeated.

Subsequently, as shown in Fig. 5 (j), after the step, the copper film 105 is flattened. By removing this planarized copper film 105 from the entire surface by wiping, mechanical polishing or the like, the current value flowing from the copper film 105 through the electrolyte solution EL to the cathode member 120 has a maximum once.

Subsequently, as shown in FIG. 5 (k), for the entire surface of the planarized copper film 105, the removal process of the chelate film 106 produced by anodization is performed on the barrier film 103. It continues until the copper film 105 disappears.

Subsequently, as shown in Fig. 5 (l), the entire surface of the copper film 105 is removed by, for example, wiping, mechanical polishing, or the like described above, and the surface of the barrier film 103 is exposed. . At this time, since the barrier film 103 having a larger electrical resistance than the copper film 105 is exposed, the current value after the removal of the chelate film 106 begins to decrease. When the current value starts to decrease, the application of the voltage is stopped to stop the chelation by anodic oxidation. By the processes so far, planarization of initial unevenness of the copper film 105 is achieved.

Thereafter, the copper wiring is formed by removing the barrier film 103 deposited on the outside of the wiring groove.

According to the polishing method according to the present embodiment, since the polishing assists the polishing rate electrochemically, polishing can be performed at a lower processing pressure than general chemical mechanical polishing. This is very advantageous in terms of scratch reduction, step reduction performance, dishing and erosion reduction, etc., compared with simple mechanical polishing.

In addition, since it can be polished at a low processing pressure, it is useful when an organic low dielectric constant film or a porous low dielectric constant insulating film is used as the interlayer insulating film 102, which tends to be broken in general chemical mechanical polishing with weak mechanical strength.

When a slurry containing alumina particles or the like is used in general chemical mechanical polishing, particles which are left unpolished after being donated to CMP processing or are buried on a copper surface are produced. In the polishing method of the present invention, abrasive polishing is performed. Even in mechanical polishing or wiping using a chelating agent containing no) as an electrolytic solution, the chelating film 106 formed on the surface is extremely low in mechanical strength, and thus can be sufficiently removed.

In addition, by monitoring the electrolytic current, the polishing process can be managed, and the progress of the polishing process can be accurately understood.

The polishing method according to the present invention is not limited to the above embodiment. For example, even when copper is used for a portion other than the wiring, it can be applied to polishing or flattening of copper, and does not deviate from the gist of the present invention such as the kind of the chelating agent or the type of the negative electrode member 120. Many changes are possible.

In addition, the manufacturing method of the semiconductor manufacturing apparatus which concerns on this invention is not limited to the said embodiment. For example, as a method other than the copper polishing method, contact hole or wiring groove forming method, copper film 105 forming method, barrier film 103 forming method and the like do not depart from the gist of the present invention. Many changes are possible.

Composition of the polishing device

It is a figure which shows the structure of the grinding | polishing apparatus which concerns on embodiment of this invention.

The polishing apparatus shown in FIG. 6 includes a processing head portion, a controller 55 having a function of controlling the electrolytic power supply 61 and the entire polishing apparatus, a slurry supply apparatus 71, and an electrolyte supply apparatus 81. have.

In addition, although not shown, a polishing apparatus is installed in a clean room, in which the wafer is placed between the wafer cassette and the polishing apparatus brought into the clean room through an export port for carrying in and out of the wafer cassette containing the wafer to be polished. A wafer transfer robot for sending and receiving is installed between the loading and unloading port and the polishing apparatus.

An abrasive tool support portion 10 (abrasive tool) rotation support means for supporting and rotating the abrasive tool 11) and a Z axis positioning mechanism portion 30 for positioning the abrasive tool support portion 10 at a target position in the Z axis direction; The processing head part is comprised by the movement positioning means) and the X-axis movement mechanism part 40 (rotation support means and relative movement means) which support, rotate, and move to the X-axis direction by supporting the wafer W which is to-be-polished.

The Z-axis positioning mechanism portion 30 is connected to the ball screw shafts 31a and 49a connected to the Z-axis servo motor 31 fixed to a column (not shown), and to the support devices 13 and 45 and the main shaft motor 14. And a Z-axis slider 32 having a threaded portion screwed to the ball screw shaft, and a guide rail 33 provided in an unillustrated column to freely support the Z-axis slider 32 in the Z-axis direction.

The Z-axis servo motor 31 is driven to rotate by being supplied with a drive current from the Z-axis driver connected to the Z-axis servo motor 31. The ball screw shafts 31a and 49a are installed along the Z-axis direction, one end of which is connected to the Z-axis servo motor 31 and the other end of which is freely supported by a support member installed on the column (not shown). Is screwed to the threaded portion of the Z-axis slider 32.

According to the above configuration, the ball screw shafts 31a and 49a are rotated by the drive of the Z-axis servo motor 31, and the polishing tool 11 supported by the polishing tool support 10 via the Z-axis slider 32 is provided. Is moved to an arbitrary position in the Z-axis direction. The positioning accuracy of a Z-axis positioning mechanism part is set to about 0.1 micrometer, for example.

The X-axis moving mechanism part 40 supports a wafer table 42 for chucking the wafer W, a drive motor 44 for supplying a driving force for rotationally driving the wafer table 42, a drive motor 44, and a support motor. X-axis provided with a belt 46 connecting the rotary shafts of the devices 13 and 45, a processing fan 47 provided on the support devices 13 and 45, and a drive motor 44 and the support devices 13 and 45. The ball screw shaft 31a is connected to the slider 48, the X-axis servo motor 49 provided on the mount (not shown), the ball screw shafts 31a and 49a connected to the X-axis servo motor, and the X-axis slider 48. And the movable member 49b with which the screw part to screw to 49a is formed.

The wafer table 42 sucks the wafer W by, for example, a vacuum suction means.

The processing fan 47 is provided in order to collect the used liquid, such as electrolyte solution and slurry.

The drive motor 44 is connected to the table driver 53, and is driven by supplying a drive current from the table driver 53. By controlling the drive current, the wafer table 42 is rotated at a predetermined rotation speed. Can be rotated.

The X-axis servo motor 49 is connected to the X-axis driver 54, and is driven to rotate by the drive current supplied from the X-axis driver 54, and the X-axis slider 48 has a ball screw shaft 31a, It drives in the X-axis direction via 49a) and the movable member 49b. At this time, by controlling the drive current supplied to the X-axis servo motor 49, the speed control of the wafer table in the X-axis direction becomes possible.

The slurry supply device 71 supplies the slurry to the wafer W through a supply nozzle 20a (not shown). As the slurry for polishing a copper film, for example, aluminum oxide (alumina), cerium oxide, silica, germanium oxide, and the like are contained as abrasive grains in an oxidizing aqueous solution based on hydrogen peroxide, iron nitrate, potassium ureate, or the like. I am using the one I made.

The electrolyte supply device 81 supplies the electrolyte EL containing a chelating agent to the wafer W through a supply nozzle 20a (not shown). As the chelating agent, for example, the above-mentioned quinalic acid, glycine, citric acid, oxalic acid, propionic acid and the like are used.

FIG. 7: is a figure which shows the internal structure of the grinding | polishing tool support part 10 of the grinding | polishing apparatus which concerns on this embodiment.

The grinding | polishing tool support part 10 is the support apparatus which rotationally supports the grinding | polishing tool 11, the flange member 12 which supports the grinding | polishing tool 11, and the flange member 12 through the spindle 12a, 13a. 13 and 45, the main shaft motor 14 which rotates the main shaft supported by the support apparatus, and the cylinder apparatus 15 provided in the main shaft motor 14 is comprised.

The main shaft motor 14 is, for example, a direct drive motor, and a rotor (not shown) of the direct drive motor is connected to the main shaft.

In addition, the main shaft motor 14 has a through-hole into which the piston rod 15b of the cylinder apparatus 15 is inserted in the center part. The spindle motor 14 is driven by the drive current supplied from the spindle driver 52.

The support apparatuses 13 and 45 are equipped with the air bearing, for example, and rotationally supports the main shaft 12a, 13a by this air bearing. The main shaft of the support devices 13 and 45 also has a through hole into which the piston rod 15b is inserted.

The flange member 12 is formed of a metal material, is connected to the main shaft, has an opening 23a, and the polishing tool 11 is fixed to the bottom surface 12b.

Since the upper end surface 12c side of the flange member 12 is connected to the main shaft, the flange member 12 also rotates in accordance with the rotation of the main shaft.

The upper surface 12c of the flange member 12 is in contact with the energizing brush 27 fixed to the conductive energizing member 28 (cathodic energizing member) provided on the side surfaces of the main shaft motor 14 and the supporting devices 13 and 45. The electrically conductive brush 27 and the flange member 12 are electrically connected.

The cylinder device 15 is fixed to the case of the main shaft motor 14, has a built-in piston 15a, and the piston 15a has an arrow (e.g., air pressure supplied into the cylinder device 15). It is driven in either direction of A1) and (A2).

The piston rod 15b is connected to the piston, and the piston rod 15b protrudes from the opening 23a of the flange member 12 through the center of the spindle motor 14 and the support devices 13 and 45. have.

The pressing member 21 is connected to the front-end | tip of the piston rod 15b, and this pressing member 21 is connected with the piston rod 15b by the coupling mechanism which can change a posture in a predetermined range.

The pressing member 21 is able to contact the edge portion of the opening 22a of the insulating plate 22 disposed at the opposite position, and the insulating plate 22 is driven by driving in the direction of the arrow A2 of the piston rod 15b. Press).

The through hole is formed in the center part of the piston rod 15b of the cylinder device 15, and the electricity supply shaft 20 is inserted in the through hole, and is fixed with respect to the piston rod 15b.

The conduction shaft 20 is formed of a conductive material, and the upper end side extends through the piston of the cylinder apparatus 15 to the rotary joint 16 installed in the cylinder apparatus 15, and the lower end side thereof is the piston rod 15b and the pressing member. It penetrates through 21 and extends to the electrode plate 23 and is connected to the electrode plate 23.

The through shaft is formed in the center of the energizing shaft 20, and this through hole is the supply nozzle 20a which supplies the electrolyte solution containing a chemical abrasive (slurry) and a chelating agent to the wafer (W).

In addition, the energization shaft 20 plays a role of electrically connecting the rotary joint 16 and the electrode plate 23.

The rotary joint 16 is electrically connected to the anode of the electrolytic power supply 61, and maintains the electricity supply to the electricity supply shaft 20 even if the electricity supply shaft 20 rotates.

The electrode plate 23 (anode member) connected to the lower end portion of the current carrying shaft 20 is made of a metal material, and is formed of a metal that is more precious than the copper film formed on the wafer W.

The upper surface side of the electrode plate 23 is supported by the insulating plate 22, the outer circumferential portion of the electrode plate 23 is fitted to the insulating plate 22, and a scrub member is adhered to the lower surface side.

The insulating plate 22 is formed of an insulating material such as ceramics, for example, and the insulating plate 22 is connected to the main shaft by a plurality of rod-shaped connecting members 26. The connection member 26 is arrange | positioned at equal intervals at the predetermined radial position from the center axis of the insulating plate 22, and movement is supported freely with respect to the main shaft 12a, 13a. To this end, the insulating plate 22 is movable in the axial direction of the main shaft.

Moreover, between the insulating plate 22 and the main shaft, it is connected with the elastic member 25 which consists of coil springs corresponding to each connection member 26, for example.

By supplying the high pressure air to the cylinder device 15, the insulating plate 22 is freely moved with respect to the main shafts of the support devices 13 and 45, and the insulating plate 22 and the main shaft are connected by the elastic member 25. By lowering the piston rod 15b in the direction of the arrow A2, the pressing member 21 pushes the insulating plate 22 downward in response to the restoring force of the elastic member 25, and at the same time the scrub member 24 Also descends.

When the supply of high pressure air to the cylinder device 15 is stopped in this state, the insulating plate 22 is raised by the restoring force of the elastic member 25, and the scrub member 24 is also raised.

The polishing tool 11 is fixed to the annular bottom surface 12b of the flange member 12. This grinding | polishing tool 11 is formed in wheel shape, and the lower surface 12b is equipped with the annular grinding | polishing surface 11a. The abrasive tool 11 is conductive and is preferably formed of a relatively soft material. For example, the porous binder matrix (binder) itself is made of porous carbon or resin such as urethane resin, melamine resin, epoxy resin, polyvinyl acetal (PVA) containing conductive material such as sintered copper or metal compound. Sieve.

The polishing tool 11 is directly connected to the conductive flange member 12 and is energized from the energization brush 27 which contacts the flange member 12.

That is, the conductive energizing member provided on the side surfaces of the main shaft motor 14 and the supporting devices 13 and 45 is electrically connected to the cathode of the electrolytic power supply 61, and the conductive brush 27 provided on the energizing member is the flange member 12. ), The polishing tool 11 is electrically connected to the electrolytic power supply 61 via the electrolytic power supply 61, the electricity supply member, the electricity supply brush 27, and the flange member 12 by this.

The electrolytic power supply 61 (61 (current supply means)) applies the predetermined voltage between the said rotary joint 16 and the electricity supply member 28 (cathode electricity supply member), and the grinding | polishing tool 11 and the scrub member 24 are carried out. A potential difference occurs between them.

The electrolytic power supply 61 is not a constant voltage power supply which always outputs a constant voltage. Preferably, the voltage is output in a pulse form of a constant cycle. For example, use a DC power supply with a built-in switching regulator circuit.

Specifically, a power supply capable of outputting a pulsed voltage at regular intervals and suitably changing the pulse width is used. For example, an output voltage of 150 V, a maximum output of 2 to 3 A, and a pulse width of 1, 2, 5, 10, 20, or 50 μsec may be used.

The short pulse voltage output as described above is intended to reduce the amount of anodic oxidation per pulse. That is, copper according to the sudden change of the inter-pole distance, which is considered to be the case of contact with the unevenness of the copper film formed on the surface of the wafer W, spark discharge due to the sudden change of the electrical resistance which occurs when bubbles or particles are interposed. Preventing sudden and massive anodic oxidation of the membrane, and making as little as possible is effective to achieve a small amount of continuity of anodic oxidation.

In addition, since the output voltage is relatively high compared to the output current, a certain margin can be set in setting the distance between the poles. In other words, even if the distance between poles is slightly changed, the change in current value is small because the output voltage is high.

The electrolytic power supply 61 is provided with an ammeter 62 as a current detection means of the present invention. The ammeter 62 is provided for monitoring the electrolytic current flowing through the electrolytic power supply 61, and the monitored current value. The signal 62s is output to the controller.

The electrolytic power supply 61 may be provided with an ohmmeter as a resistance value detecting means, unlike the current detecting means, and its role is the same as that of the current detecting means.

The controller 55 has a function of controlling the whole polishing apparatus, specifically, outputs a control signal to the spindle driver 52 to control the rotation speed of the polishing tool 11, and to the Z-axis driver. Outputting a control signal to control the positioning of the polishing tool 11 in the Z-axis direction, outputting a control signal to the table driver 53 to control the rotation speed on the wafer W, and the X-axis driver 54 The control signal is output to the speed of the wafer W in the X-axis direction.

In addition, the controller 55 controls the operations of the electrolyte supply device 81 and the slurry supply device 71, and controls the supply operation of the electrolyte solution EL and the slurry S to the processing head.

In addition, the controller 55 can control the output voltage of the electrolytic power supply 61, the frequency of the output pulse, the width of the output pulse, and the like.

In addition, the controller 55 receives a current value signal 62s from the electrolytic power supply 61 ammeter 62. The controller 55 can control the operation of the polishing apparatus on the basis of these ammeter 62 signals. Specifically, the Z-axis servo motor 31 is controlled by the current value signal 62s as the feedback signal or determined by the current value signal 62s so that the electrolytic current obtained from the current value signal 62s becomes constant. The operation of the polishing apparatus is controlled to stop the polishing processing based on the losing current value.

The control panel connected to the controller 55 inputs various data by the operator, for example, displays the monitored current value signal 62s.

Here, FIG. 8A is a bottom view showing an example of the structure of the electrode plate 23, and FIG. 8B shows the electrode plate 23, the energizing shaft 20, and the scrub member 24 ( It is sectional drawing which shows the positional relationship with the cleaning member) and the insulating plate 22. As shown in FIG.

As shown in FIG. 8A, a circular opening 23a (supply nozzle) is provided at the center of the electrode plate 23, and in the radial direction of the electrode plate 23 around the opening 23a. A plurality of grooves 23b extending radially are formed.

In addition, as shown in FIG. 8B, the lower end of the energization shaft 20 is fitted into the opening 23a of the electrode plate 23.

By such a configuration, the slurry and the electrolyte solution supplied through the supply nozzle 20a formed in the center of the energization shaft 20 are diffused to the entire surface of the scrub member 24 through the groove portion 23b. .

That is, as the electrode plate 23, the energizing shaft 20, the scrub member 24, and the insulating plate 22 rotate, the slurry and the electrolyte are applied to the upper side of the scrub member 24 through the supply nozzle 20a. When supplied, the slurry and the electrolyte are spread over the entire upper side of the scrub member 24.

In addition, the supply nozzle 20a of the scrub member 24 and the electricity supply shaft 20 corresponds to the specific example of the abrasive supply means and electrolyte solution supply means of this invention.

The scrub member 24 adhered to the lower surface of the electrode plate 23 is formed of a material capable of absorbing the electrolyte solution and the slurry and allowing it to pass from the upper surface axis to the lower surface side. In addition, the scrub member 24 has a surface in contact with the wafer W to scrub the wafer W, so that a scratch or the like does not occur on the surface of the wafer W, for example, in a soft brush shape. A material, a sponge material, a porous material, and the like are formed. For example, the porous body which consists of resins, such as a urethane resin, a melamine resin, an epoxy resin, and polyvinyl acetal (PVA), is mentioned.

9 shows the positional relationship between the polishing tool 11 and the wafer at the time of polishing.

The central axis of the polishing tool 11 is inclined at a fine angle with respect to the wafer W, for example. The main axes of the support devices 13 and 45 are also inclined with respect to the main surface of the wafer W in the same manner as the inclination of the polishing surface 11a. For example, by adjusting the attachment posture of the support devices 13 and 45 to the Z-axis slider 32, the slight inclination of the main axis can be produced.

In this way, when the central axis of the polishing tool 11 is inclined at a small angle with respect to the main surface of the wafer W, when the inclined surface of the polishing tool 11 is pressed against the wafer W at a predetermined processing pressure F In practice, the contact area remains constant.

In the polishing apparatus according to the present embodiment, a part of the polishing tool 11 is partially used as the polishing surface 11a to act on the surface of the wafer W, and the effective contact area is uniform on the surface of the wafer W. Scanning is performed to uniformly polish the entire surface of the wafer W.

As a result, when the electrolytic current value is constantly controlled, the current density is always constant, so that the amount of chelation by anodic oxidation of the copper film can always be constant.

Next, a case where the polishing operation (polishing method) by the polishing apparatus is used to polish the copper film formed on the surface of the wafer W will be described as an example. 10 is a schematic diagram showing a state in which the polishing tool 11 is lowered in the Z-axis direction in the polishing apparatus to be in contact with the surface of the wafer W. As shown in FIG.

First, the wafer W is chucked to the wafer table 42, and the wafer table 42 is driven to rotate the wafer W at a predetermined rotational speed.

In addition, the wafer table 42 is moved in the X-axis direction, the polishing tool 11 attached to the flange member 12 is disposed at a predetermined place above the wafer W, and the polishing tool 11 is predetermined. When the polishing tool 11 is rotated, the insulating plate 22, the electrode plate 23, and the scrub member 24 connected to the flange member 12 are also driven to rotate. The pressing member 21, the piston rod 15b, the piston 15a, and the energizing shaft 20, which hold down), also rotate at the same time.

In this state, when the slurry SL and the electrolyte EL are respectively supplied from the slurry supply device 71 and the electrolyte supply device 81 to the supply nozzle 20a in the energization shaft 20, the scrub member 24 is provided. The slurry SL and the electrolytic solution EL are supplied from the whole surface of the.

The polishing tool 11 is lowered in the Z-axis direction, the polishing surface 11a of the polishing tool 11 is brought into contact with the surface of the wafer W, and pressed at a predetermined processing pressure.

Furthermore, the electrolytic power supply 61 is started, the negative electric potential is applied to the grinding | polishing tool 11 via the electricity supply brush 27, and the positive electric potential is applied to the scrub member 24 via the rotary joint 16. As shown in FIG.

In addition, the high pressure air is supplied to the cylinder device 15, and the piston rod 15b is lowered in the direction of an arrow A2 in FIG. 7, so that the lower surface of the scrub member 24 contacts or approaches the wafer W. As shown in FIG. Move to position

In this state, the wafer table 42 is moved at a predetermined speed pattern in the X-axis direction, and the entire surface of the wafer W is polished at a constant level.

FIG. 11 is an enlarged view in circle C of FIG. 10, and FIG. 12 is an enlarged view in circle D of FIG. 11.

As shown in FIG. 11, the scrub member 24 energizes the copper film MT formed on the wafer W as an anode through the electrolytic solution EL or by direct contact with the polishing tool 11. The copper film MT formed on the wafer W is energized as a cathode through the electrolytic solution EL or by direct contact. In addition, as shown in FIG. 11, a gap δ _b exists between the copper film MT and the scrub member 24. As shown in FIG. 12, a gap δ _w exists between the copper film MT and the polishing surface 11a of the polishing tool 11.

As shown in FIG. 11, the insulating plate 22 is interposed between the abrasive tool 11 and the scrub member 24, but the resistance of the insulating plate 22 is very large, and thus, through the scrub member 24. The current i ₀ flowing to the polishing tool 11 is almost zero, and no current flows from the scrub member 24 to the polishing tool 11 through the insulating plate 22.

Therefore, the disk current flowing from Love member 24 to the polishing tool (11), and direct the electrolyte (EL) in the resistor (R1), current (i ₁₎ flowing through the polishing tool (11) by way of the electrolyte (EL Is branched into the current i ₂ flowing through the electrolytic solution EL to the polishing tool 11 via the copper film MT formed on the surface of the wafer W.

When the current i flows on the surface of the copper film MT, the copper constituting the copper film MT is anodized by the electrolytic action of the electrolyte EL and is chelated by the chelating agent in the electrolyte.

Here, the resistance R1 of the electrolytic solution EL song becomes very large in proportion to the distance d between the scrub member 24 as the anode and the polishing tool 11 as the cathode. For this reason, the current i ₁ flowing through the resistance R1 in the electrolyte EL directly through the resistance R1 in the electrolyte EL by making the gap distance d sufficiently larger than the gap δ _b and the gap δ _w . ) Becomes very small and the current i ₂ becomes large so that most of the electrolytic current passes through the surface of the copper film MT. Therefore, chelation by anodic oxidation of copper constituting the copper film MT can be efficiently performed.

In addition, since the magnitude of the current i ₂ changes depending on the magnitude of the gap δ _b and the gap δ _w , the controller controls the position of the polishing tool 11 in the Z-axis direction as described above. By adjusting the magnitudes of the gap δ _b and the gap δ _w , the current i ₂ can be made constant. Adjusting the size of the gap δ _w controls the control of the Z-axis servo motor 31 using the current value signal 62s as a feedback signal so that the electrolytic current obtained from the current value signal 62s, that is, the current i ₂ is constant. You can do it.

In addition, the positioning accuracy in the Z-axis direction of the polishing apparatus is not only high enough at a resolution of 0.1 µm, but also the main axes 12a and 13a can be inclined at a small angle with respect to the main surface of the wafer W, thereby providing practical contact. The area can always be kept constant. Therefore, when the electrolytic current value is constantly controlled, the current density is always constant, and the amount of chelation by anodic oxidation of the copper film can always be constant.

As described above, the polishing apparatus having the above-described structure has an electropolishing function of generating and removing a chelate film by anodization on the surface of the copper film MT formed on the wafer W described above.

In addition to the electropolishing function, the polishing apparatus of the above-described configuration includes not only the electromechanical polishing function but also the chemical mechanical polishing function of the general CMP device by the polishing tool 11 and the slurry SL. Polishing (hereinafter referred to as electrolytic compound polishing) may also be performed by a compound action of mechanical polishing.

Moreover, the polishing apparatus of the said structure can also grind | polish by the combined action of the mechanical polishing of the polishing surface 11a of the polishing tool 11, and electrolytic polishing function, without using slurry SL.

According to the polishing apparatus according to the present embodiment, the copper film can be polished by a combination action of electrolytic polishing and chemical mechanical polishing, so that the copper film is removed much more efficiently than the polishing apparatus using only chemical mechanical polishing or only mechanical polishing. can do. Since a high polishing rate for the copper film is obtained, it is possible to suppress the processing pressure F for the wafer W of the polishing tool 11 lower than that of a polishing apparatus using only chemical mechanical polishing or only mechanical polishing. Thus, dishing and erosion can be suppressed.

In addition, when a slurry containing alumina particles or the like is used in a slurry used for general chemical mechanical polishing, a slurry may be left or buried on the copper surface without polishing after polishing. In the polishing apparatus according to the present embodiment, polishing is performed. Even in simple mechanical polishing using an electrolytic solution containing no abrasive grains, the chelate film remaining on the surface has a very low mechanical strength, and thus can be sufficiently removed, and particles or slurry can be prevented from remaining on the wafer surface.

In addition, the positioning accuracy in the Z-axis direction of the polishing apparatus is not only high enough at a resolution of 0.1 µm, but also the main axis can be inclined at a small angle with respect to the main surface of the wafer W, so that the practical contact area is always kept constant. Can be. Therefore, when the electrolytic current value is constantly controlled, the current density is always constant, and the amount of chelation by anodic oxidation of the copper film can always be constant.

In the above-described embodiment, the absolute value of the polishing processing amount of the copper film can be removed by the time passing through the integrated amount of the electrolytic current and the wafer W of the polishing tool 11.

Variant  One

13 is a schematic view showing a modification of the polishing apparatus according to the present invention. In the polishing apparatus according to the above-described embodiment, electricity was supplied to the surface of the wafer W by the electrode plate 23 provided with the conductive polishing tool and the scrub member.

As shown in FIG. 13, the wheel-shaped polishing tool 311 has conductivity as in the case of the above-described polishing apparatus, and also has conductivity in the wafer table 342 in which the wafer W is chucked and rotated. It is good also as a structure. The electric power feeding to the grinding | polishing tool 311 is set as the structure similar to embodiment mentioned above.

In this case, the electricity supply to the wafer table is provided by providing a rotary joint at the lower portion of the wafer table, and maintaining the electricity supply to the rotating wafer table by the rotary joint 316 so that the electrolytic current can be supplied. have.

Variant  2

14 is a schematic view showing another modified example of the polishing apparatus according to the present invention.

The wafer table 442 that chucks and rotates the wafer W supports the wafer W by a retainer ring provided around the wafer W. As shown in FIG.

The polishing tool 411 is made conductive and at the same time, the retainer ring 410 is made electrically conductive, and the polishing tool is fed with the same configuration as the above-described embodiment.

In addition, the retainer ring is energized by covering up to the barrier layer portion formed in the wafer (W). In addition, the retainer ring is fed through a rotary joint 416 provided at the bottom of the wafer table.

In addition, even when the polishing tool is in contact with the wafer W, by increasing the inclination amount of the polishing tool so that the gap of the retainer ring thickness or more is maintained at the edge portion, the interference between the polishing tool and the retainer ring can be prevented.

Variant  3

15 is a schematic configuration diagram showing another embodiment of the polishing apparatus according to the present invention.

The polishing apparatus shown in FIG. 15 adds the electrolytic polishing function of the present invention to a conventional CMP apparatus, and the wafer chuck 207 on the polishing surface of the polishing tool to which the polishing pad (polishing cloth) is adhered to the surface plate 201. It is a polishing apparatus that flatten the surface of the wafer (W) by contacting while rotating the entire surface of the wafer (W) chucked by).

In the polishing pad 202, the anode electrode 204 and the cathode electrode 203 are alternately arranged radially. The anode electrode and the cathode electrode are electrically insulated by the insulator 206, and the anode electrode and the cathode electrode are energized from the surface plate side. The polishing pad 202 is composed of these anode electrodes, cathode electrodes, and insulators.

In addition, the wafer chuck is formed of an insulating material.

In addition, the polishing apparatus is provided with a supply section 208 for supplying the electrolytic solution EL and the slurry SL on the surface of the polishing pad, which enables electrolytic composite polishing in which electrolytic polishing and chemical mechanical polishing are combined.

Here, FIG. 16 is a figure for demonstrating the electrolytic compound polishing operation (polishing method) by the polishing apparatus of the said structure. In addition, a copper film is formed on the wafer W surface.

As shown in FIG. 16, during the electrolytic composite polishing, the anode electrode is provided between the copper film 210 formed on the surface of the wafer W and the polishing surface of the polishing pad, with the electrolyte EL and the slurry SL interposed therebetween. DC voltage is applied between the anode and the cathode, and the current i flows from the anode electrode through the electrolyte EL to the inside of the copper film and flows back through the electrolyte EL to the cathode electrode.

At this time, in the vicinity of the circle G shown in FIG. 16, the surface of the copper film generates a chelating agent by anodization, and the chelating film is removed by mechanical removal action by the polishing pad and slurry SL, thereby removing copper. Leveling is achieved.

By such a structure, the effect similar to the grinding | polishing apparatus which concerns on embodiment mentioned above is exhibited.

In addition, the arrangement of the anode electrode and the cathode electrode provided in the polishing pad is not limited to the configuration of FIG. 15. For example, as shown in FIG. The cathode electrode 223 may be arranged in each rectangular region surrounded by the anode electrode 222, and the polishing pad may be electrically insulated from the anode electrode and the cathode electrode with the insulator 224.

For example, as shown in FIG. 18, the annular anode electrodes 242 having different radii are arranged concentrically, and the cathode electrodes 243 are disposed in the annular regions formed between the anode electrodes, respectively. The polishing pad 241 may be electrically insulated from the anode electrode and the cathode electrode with the insulator 244.

The polishing apparatus of the present invention is not limited to the above-described embodiment. For example, the material which comprises an apparatus, the energization method to a wafer, etc. can be variously changed in the range which does not deviate from the summary of this invention.

2nd Embodiment

It is a schematic block diagram of the grinding | polishing apparatus which concerns on 2nd Embodiment of this invention. The polishing apparatus according to the present embodiment includes a water tank 501 filled with a predetermined amount of the electrolytic solution EL, wafer support means 530 and an electrode plate 510 disposed in the electrolytic solution 500 of the water tank, A jet pump 520 (flow means) for sucking up the electrolyte by the tube 522, dividing it by the tube 521, and sending it out, the electrode plate 510 as the cathode, and the wafer as the anode And a power source 561 (electrolytic current supply means) for applying a voltage, an ammeter 562, a controller 555, and a control panel 556.

The supporting means 530 is fixed to the conductive first supporting member 531 and the conductive second supporting member 532 to fix the wafer, and to a column, not shown, to move the first supporting member and the second supporting member to a predetermined position. Z-axis positioning mechanism 533 is fixed to the. The second support member located below the wafer has a circular opening in the portion 532 (a).

The electrode plate 510 is disposed in parallel with the wafer in the electrolyte EL, and is made of, for example, oxygen-free copper or the like.

Electrolyte (EL) contains the chelating agent which chelates copper, for example, and may also contain other additives. Kinases, glycine, citric acid, propionic acid and the like are used as chelating agents. Examples of the additive include an electrolyte such as copper sulfate for reducing the voltage applied between the wafer and the electrode plate 510.

The electrolytic power supply 561 (electrolytic current supply means) is not a constant voltage power supply that always outputs a constant voltage, but preferably a DC power supply that outputs a voltage in a pulse form of a constant cycle. For example, depending on the square DC pulse voltage (for example, 30 to 40 V, current 2.2 A, and breakdown voltage of the semiconductor element), the voltage applied by the electrolytic power supply repeats the high voltage and the low voltage every 5 seconds. For example, 10 to 20 V).

As the DC pulse voltage, a voltage and a pulse width capable of removing the copper film most efficiently can be selected according to the distance d between the wafer and the electrode plate 510 and the like.

If the distance d between the electrode plate 510 and the wafer is too small. Since the flow action of the electrolyte solution interposed between the electrode plate 510 and the wafer does not sufficiently function, the distance d is preferably at least a predetermined value, and is preferably set in accordance with the voltage. .

The electrolytic power source 561 is provided with an ammeter as a current detecting means of the present invention, and this ammeter 562 is provided to monitor the electrolytic current flowing through the electrolytic power source, and the controller monitors the monitored current value signal 562s. To 555.

The controller also receives a current value signal from the ammeter of the electrolytic power supply. The controller is capable of controlling the operation of the polishing apparatus based on these current value signals. Specifically, the operation of the polishing apparatus is controlled to stop the polishing process based on the current value determined by the current value signal.

The control panel connected to the controller inputs various data by the operator or displays, for example, the monitored current value signal.

By the configuration of the polishing apparatus, similarly to the polishing apparatus according to the first embodiment, for example, when a copper film with irregularities is formed on the surface of the wafer W, the wafer W is used as an anode and the voltage is reduced. By applying, the surface of the copper film of the wafer W is anodized, and this anodized copper film is chelated by a chelating agent in the electrolytic solution EL, and this chelate is very weak in mechanical strength, so the jet pump 520 The convex portion of this chelate film is removed by the flow action of the electrolytic solution from the tube 521 of the c) film, thereby achieving flattening removal of the copper film.

In addition, by monitoring the electrolytic current, the polishing process can be managed, and it is possible to accurately grasp the progress of the polishing process.

According to the polishing apparatus of the present embodiment, the removal of the copper film can be achieved by removing the chelate film having a very low mechanical strength, which is much higher than that of the conventional polishing apparatus using only chemical mechanical polishing or only mechanical polishing. The copper film can be removed efficiently.

Since it is not necessary to apply strong pressure as in conventional mechanical polishing, damage to the interlayer insulating film or the like under the copper film can be suppressed, and occurrence of dishing, erosion and the like can be suppressed. Since no high pressure is applied to the insulating film under the copper film, a low dielectric constant material having a lower mechanical strength than silicon oxide based on TEOS or the like can be used as the insulating film material.

In addition, when a slurry containing alumina particles or the like is used in a slurry used for general chemical mechanical polishing, the slurry may remain or be buried on the copper surface without being polished after polishing. In the polishing apparatus according to the present embodiment, such a problem There is no.

This invention is not limited to said embodiment. For example, various changes are possible in the range which does not deviate from the summary of this invention, such as the structure of a jet pump, the kind of electrode plate, and the structure of the apparatus which supports the wafer in a water tank.

Third embodiment

20 is a schematic configuration diagram of a polishing apparatus according to a third embodiment of the present invention. In the polishing apparatus according to the present embodiment, an excitation means composed of a pulse generator 640, an amplifier 641, an exciter 643, a water tank 601 filled with a predetermined amount of an electrolyte EL, And a power supply 661 (electrolytic current supply means) for applying a voltage using the wafer supporting means 630 disposed in the bath electrolyte EL and the electrode plate 610 as the cathode and the wafer as the anode. And an ammeter 662, a controller 655, and a control panel 656.

The support means 630 includes a first support member 631 for supporting the electrode plate 610 in parallel with the wafer W, a second support member 632 and a third support for interposing the wafer and then pressing and fixing the wafer. The member 634 and the one end are attached to the 2nd member, and the other end is comprised by the 4th support member 633 attached to the excitation machine.

The second support member 632 is made of a conductive material and serves to conduct electricity by using the wafer W as an anode. The second member also has an opening portion 632a for opening the surface of the wafer with respect to the electrode plate 610.

Electrolyte solution EL may contain the chelating agent which chelates copper, for example. As the chelating agent, chiral acid, glycine, citric acid, oxalic acid, propionic acid and the like are used. Examples of the additive include an electrolyte such as copper sulfate for reducing the voltage applied between the wafer and the electrode plate.

The electrode plate is disposed parallel to the wafer in the electrolyte EL, and is made of, for example, oxygen-free copper or the like.

The electrolytic power supply 661 (electrolytic current supply means) is not a constant voltage power supply that always outputs a constant voltage, but preferably a DC power supply that outputs a voltage in a pulse form of a constant cycle. For example, depending on the square DC pulse voltage (for example, 30 to 40 V, current 2.2 A, and breakdown voltage of the semiconductor element), the voltage applied by the electrolytic power supply repeats the high voltage and the low voltage every 5 seconds. For example, 10 to 20 V).

As the DC pulse voltage, a voltage and a pulse width capable of removing the copper film most efficiently can be selected according to the distance d between the wafer and the electrode plate 610 and the like.

If the distance d between the electrode plate and the wafer is too small. Since the circulation action of the electrolyte solution interposed between the electrode plate and the wafer does not sufficiently function, the distance d is preferably set to a predetermined value or more, and preferably set according to the voltage.

The electrolytic power supply 661 is provided with an ammeter 662 as a current detecting means of the present invention, which is installed to monitor the electrolytic current flowing through the electrolytic power supply, and controls the monitored current value signal 662s. Output to (655).

The controller also receives a current value signal from the ammeter of the electrolytic power supply. The controller is capable of controlling the operation of the polishing apparatus based on these current value signals. Specifically, the operation of the polishing apparatus is controlled to stop the polishing process based on the current value determined by the current value signal.

The control panel connected to the controller inputs various data by the operator or displays, for example, the monitored current value signal.

Similarly to the polishing apparatus according to the first embodiment, according to the configuration of the polishing apparatus, for example, when a copper film having irregularities is formed on the surface of the wafer W, the wafer W is used as the anode. By applying a voltage, the surface of the copper film of the wafer W is anodized, and this anodized copper film is chelated by a chelating agent in the electrolytic solution EL. By vibrating means from this, the convex part of this chelate film is removed and planarization removal of a copper film is achieved.

In addition, by monitoring the electrolytic current, the polishing process can be managed, and it is possible to accurately grasp the progress of the polishing process.

According to the polishing apparatus of the present embodiment, the removal of the copper film can be achieved by removing the chelate film having a very low mechanical strength, which is much higher than that of the conventional polishing apparatus using only chemical mechanical polishing or only mechanical polishing. The copper film can be removed efficiently.

Since it is not necessary to apply strong pressure as in conventional mechanical polishing, damage to the interlayer insulating film or the like under the copper film can be suppressed, and occurrence of dishing, erosion and the like can be suppressed. Since no high pressure is applied to the insulating film under the copper film, a low dielectric constant material having a lower mechanical strength than silicon oxide based on TEOS or the like can be used as the insulating film material.

In addition, when a slurry containing alumina particles or the like is used in a slurry used for general chemical mechanical polishing, the slurry may remain or be buried on the copper surface without being polished after polishing. In the polishing apparatus according to the present embodiment, such a problem There is no.

This invention is not limited to said embodiment. For example, various modifications are possible within the scope not departing from the gist of the present invention, such as the configuration of the exciter and amplifier, the type of electrode plate, and the configuration of the apparatus for supporting the wafer in the tank.

Fourth embodiment

21 is a schematic configuration diagram of a polishing apparatus according to the present invention. Although the basic structure is the same as that of 1st Embodiment, in this embodiment, an abrasive tool is not used. Instead, the metal film on the wafer is removed by the wiping member 24a.

Therefore, only components different from the first embodiment are described for simplicity.

The wiping member 24a is made of polyvinyl acetal (PVA), urethane foam, teflon foam, teflon nonwoven fabric or the like, for example. Depending on the electrical properties, they need to be insulators that do not carry electricity or ions. For this purpose they are formed into fibrous forms. Therefore, the electrolyte bleeds out through the pores of the fibrous wiping member to fill the space between the electrode 22 and the wafer (W).

The wiping member 24a requires some strength for this purpose, and the surface of the wafer W needs to be pressed to remove the metal film thereon.

For example, a soft strength that does not cause scratches with elastic strength sufficient to withstand 20 to 100 g / cm ² pressure for wiping only the convex portions on the wafer W surface is required.

For example, an elastic plastic material can be used for the wiper member 24.

Further, the electrode 23 is preferably provided with pores for discharging the gas generated on the surface to be polished due to, for example, the electrolytic action of the metal film on the wafer W surface. The pores are also provided to prevent damage resulting from non-uniformity of the electrolytic action between the electrode 23 and the wafer W generated by the gas.

In addition, the electrode 23 may be provided for rotational driving. As a result, the gas generated on the surface to be polished due to the electrolytic action can be discharged from between the wafer W and the electrode 23 by the rotation of the electrode 23.

Further, the electrode 23 can be divided into several regions, whereby the electrolytic action on the surface to be polished can be selectively performed in individual regions.

Similar to the first embodiment, the electrolytic power supply 61 applies a predetermined pulse voltage between the above-described rotary joint 16 and the conductive brush 710 in contact with the wafer.

In this embodiment, the voltage is applied in the reverse direction, so that the conductive brush 710 and the electrode 23 become reversely positive and negative, respectively. In addition to the configuration of applying a voltage by contact with the metal film on the surface of the wafer W using the conductive brush 710 as described above, an electrode that may be in proximity to the metal film on the surface of the wafer W for voltage application. A configuration having a may be employed.

The conductive brush 710 transfers current from the electrolytic power supply 61 in contact with the surface of the wafer. Therefore, the electric current supplied from the electrolytic power supply 61 flows from the conductive brush 710 to the metal film on the surface of the wafer W, and passes through the electrolyte to the electrode 22.

The operation of the polishing apparatus is described below.

First, the wafer W is chucked to the wafer table 42, and the wafer table 42 is driven to rotate the wafer W at a predetermined speed.

The wafer table 42 is moved in the X-axis direction, and the wiping member 24a is positioned at a predetermined position on the wafer W and rotated at a predetermined speed. For example, it is rotated at 100 rpm.

In this state, the slurry SL and the electrolyte EL are supplied from the slurry SL supply part 71 and the electrolytic solution EL supply 81 to the supply nozzle 20a on the conductive shaft 20, thereby wiping. It spreads over the whole surface of the member 24a.

The electrolytic power source is then activated and a positive voltage is applied across the conductive brush 27 to the metal film on the wafer surface, and a negative voltage is applied across the rotary joint 16 to the electrode 23.

As a result, a positive voltage is applied directly through the conductive brush 27 to the metal film on the wafer surface, and current is transmitted to the electrode 22 via the electrolyte.

Thus, the current can be supplied through the electrolyte using the metal film under the wiping member 24a as the anode. The metal film is oxidized by the anodic oxidation generated by the electrolytic action of the electrolyte solution and chelated by the chelating agent in the electrolyte solution.

In the above state, high pressure air is supplied to the cylinder mechanism 15 to move the piston rod 15b downward, and the bottom surface of the wiping member 24a comes into contact with the surface of the wafer W. As shown in FIG.

In this state, the wafer table 42 is moved in the X-axis direction by a predetermined speed pattern, whereby the entire surface of the wafer W is uniformly wiped.

As described above, the polishing apparatus employing the above-described configuration can generate and remove the aforementioned chelate film by anodizing on the surface of the metal film formed on the wafer W.

According to the polishing apparatus of this embodiment, an effect similar to that according to the first embodiment can be obtained.

In addition, since no polishing tool is used in the polishing apparatus according to the present embodiment, the process difference of the metal film on the wafer surface can be reduced only by wiping using the wiping member 24a, and the pressure on the wafer is also reduced. It can be reduced than in the polishing apparatus according to the first embodiment.

In this embodiment, the rotation of the wiping member is described in the example of the wiping method, but the wiping member may be moved relative to the wafer W. As shown in FIG. For example, the wiping member can be moved by providing a horizontal moving means. In the case of wiping by horizontal movement, it is preferable to set at a horizontal movement speed of about 15 m / min or less in order to prevent the ejection of the electrolyte.

Preferably, the temperature of the electrolyte is adjusted to 80 ° C. or lower to promote anodization.

In addition, the electrolyte supplied to the surface of the workpiece can be fixed by the surface tension.

As mentioned above, there is no limitation on the polished object.

EMBODIMENT OF THE INVENTION Below, another embodiment using the manufacturing method, the grinding | polishing apparatus, and the grinding | polishing method of a semiconductor element which concerns on this invention is described with reference to drawings.

Fifth Embodiment

22 (A) and 22 (B) per unit time of the copper film when the copper film on the surface of the wafer W is removed for chelation by anodization using the polishing apparatus according to the third embodiment of the present invention. The removal amount and hydrogen peroxide (H) of a predetermined concentration as a copper film thinner on the surface of the wafer W in the electrolyte EL without applying a voltage to the wafer W in the polishing apparatus according to the third embodiment of the present invention. ₂ O ₂ ) is added to compare the amount of copper films removed per unit time when the copper film on the surface of the wafer W is removed by chelating according to oxidation.

In FIG. 22, (A) was removed after oxidizing and chelating copper by adding an oxidant without applying a voltage, and using a kinaldic acid solution as an electrolyte solution, and the concentration of H ₂ O ₂ was 0%, 4.5%, 8%, The removal amount (removal rate) of the copper film per unit time at 10.7% was measured. In addition, the quantity of electrolyte solution was 150 ml.

In addition, the copper film was removed using the polishing apparatus according to the third embodiment of the present invention (B), and the electrode plate and the wafer (W) without hydrogen peroxide were used using 150 ml of the kinindic acid solution as the electrolytic solution EL. ), The amount of removal (removal rate) of the copper film per unit time when a voltage was applied so that a current of 2.2 A flows through the electrolyte (EL) was measured.

When hydrogen peroxide is used as the oxidizing agent, Cu is oxidized to form copper hydride ions [[Cu (OH) ₄ ] ^2- ). The copper hydride ion is chelated by a chelating agent in the electrolytic solution (EL). For example, when the chelating agent is kinaldine, a chelate of chemical structural formula (6) is produced, and when the chelating agent is glycine, the chemical structural formula (7) ) Chelate is generated.

As other experimental conditions, a wafer of 8 inches is used, a thickness of 25 nm of Ta is used as a barrier metal, a tetra ethyl ortho silicate (TEOS) film having a thickness of 1200 nm is used as the interlayer insulating film, and the thickness of the copper film is 1600 nm. I used one.

In Fig. 22, it can be seen that as the amount of hydrogen peroxide that is an oxidizing agent increases, the amount of chelate film produced by oxidation of the copper film increases, so that the amount of removal per unit time of the copper film increases, but with the polishing apparatus of the third embodiment of the present invention. In the case of using the polishing method, it is understood that the removal rate is dramatically improved compared with the oxidizing agent without the addition of hydrogen peroxide and only chelate formation by the anodization of copper due to the energization.

6th Embodiment

Fig. 23 shows a wafer W having a copper film on its surface, using a polishing apparatus according to a third embodiment of the present invention, flowing a 2.2 A current for 30 seconds using a copper film as an anode to remove a chelated film, and then removing the chelated film. The film thickness of Cu is measured.

The measurement part measured about the 21-point part at the time of dividing an 8 inch wafer from 1 point to 21 points in the radial direction. One point and 21 points were each 6 mm from the edge of the wafer.

In the electrolytic solution, quinalic acid was used, the thickness of the Cu film was 2000 nm, the barrier metal was Ta 25 nm thick, and the wafer W having a TEOS film 1200 nm thick was used for the interlayer insulating film under the barrier metal.

In Fig. 23, 0, 1, 2, 3, 4, and 5 on the horizontal axis each represent the number of times that the current of 2.2 A was energized for 30 seconds. Thus, the current of 2.2 A was respectively applied, 0 is no electricity, and 1 was 30 seconds. , 2 is 60 seconds in total, 3 is 90 seconds in total, 4 is 120 seconds in total, and 5 is 150 seconds in total.

The vertical axis shows the film thickness (nm) of copper remaining on the wafer surface after removing copper after energization.

In addition, this measurement was performed multiple times under the same conditions.

From this measurement result, it turns out that the film thickness of the Cu film | membrane after removal decreases in proportion to an energization time as an electric current is energized for a predetermined time. Moreover, the average removal amount was 202.68 nm.

6th Embodiment

FIG. 24 shows the same result as that of FIG. 23 in each point of the wafer divided | segmented from 1 point to 21 points in the radial direction.

The energization amount and the energization time are the same as those in the second embodiment, and measure the film thickness of Cu after removal at each time point in the case where a plurality of times that the current of 2.2 A was energized for 30 seconds was repeated a plurality of times.

Other conditions, such as the kind of wafer and electrolyte solution used, are the same as that of the second embodiment.

In Fig. 24, the positions in the above-described wafer are shown from 1 point to 21 points on the horizontal axis, and the film thickness (nm) of copper after removal is shown on the vertical axis.

Each of the currents of 2.2A for 0 seconds (energization), B for 30 seconds, C for 60 seconds, D for 90 seconds, E for 120 seconds, and F for 150 seconds The film thickness of copper after removal in the body is shown.

According to this embodiment, the film thickness of the copper film at each point decreases in proportion to the product of the current and time. In addition, the small film thickness of the copper film of 1 point and 21 points originates in the characteristic of the plating at the time of formation of Cu film | membrane which is a previous step, and is irrelevant to the grinding | polishing method of this invention.

According to the manufacturing method of the semiconductor manufacturing apparatus using the grinding | polishing method of this invention, since a copper film is polished by the combined action of mechanical polishing and electrolytic polishing, copper film convex is highly efficient compared with the case of planarization of the copper film by mechanical polishing. Selective removal and planarization of the parts are made possible.

Moreover, according to the manufacturing method of the semiconductor manufacturing apparatus using the grinding | polishing method of this invention, since a sufficient grinding | polishing rate is obtained even at low grinding | polishing pressure, it can suppress that a scratch, dishing, erosion, etc. generate | occur | produce in the copper film after grinding | polishing. In addition, since damage to the insulating film of the lower copper film can be suppressed, an organic low dielectric constant film or a porous low dielectric constant insulating film having a relatively low mechanical strength as an interlayer insulating film in order to reduce the dielectric constant from the viewpoint of lowering power consumption and high speed of semiconductor elements. Even when using, it can apply easily.

Moreover, according to the manufacturing method of the semiconductor manufacturing apparatus using the grinding | polishing method of this invention, since a polishing process can be managed by monitoring an electrolytic current, it is possible to pinpoint the progress of a polishing process.

According to the polishing apparatus of the present invention, since the copper film is polished by the combined action of mechanical polishing and electrolytic polishing, the copper film convex portion can be selectively removed and planarized very efficiently compared with the case of flattening the copper film by mechanical polishing. .

In addition, according to the polishing apparatus of the present invention, since a sufficient polishing rate is obtained even at a low polishing pressure, occurrence of scratches, dishing, erosion and the like in the polished copper film can be suppressed. In addition, since damage to the insulating film of the lower copper film can be suppressed, an organic low dielectric constant film or a porous low dielectric constant insulating film having a relatively low mechanical strength as an interlayer insulating film in order to reduce the dielectric constant from the viewpoint of lowering power consumption and high speed of semiconductor elements. Even when using, it can apply easily.

In addition, according to the polishing apparatus of the present invention, since the polishing process can be managed by monitoring the electrolytic current, it is possible to accurately grasp the progress of the polishing process.

According to the polishing apparatus of the present invention, since the apparatus configuration is simple, miniaturization can be easily realized, maintenance is easy, and the operation rate can be improved.

Claims (11)

A polishing apparatus for polishing an object to be polished having a copper film on the surface to be polished, Conductive polishing tools having a polishing surface, Polishing tool rotation support means for rotating the predetermined rotation axis for rotating and supporting the polishing tool, Rotation support means for supporting the object to be polished and rotating about a predetermined rotation axis; Movement and positioning means for moving and determining the polishing tool to a target position in a direction opposite to the surface to be polished of the object to be polished, Relative movement means for relatively moving the surface to be polished and the polishing surface along a predetermined plane, An electrolytic solution supply means having a scrub member formed of a material capable of absorbing and passing an electrolytic solution, and supplying an electrolytic solution containing a chelating agent to the surface to be polished through the scrub member; Current supply means for supplying a current flowing from the surface to be polished to the polishing tool through the electrolyte from the surface to be polished with the anode as the anode and the polishing tool as the cathode Polishing apparatus comprising a. In claim 1 The current supply means is arranged to be in contact with or accessible to the surface to be polished, and to apply a predetermined voltage between the anode member and the anode member and the polishing tool to conduct electricity with the surface to be polished as an anode. Polishing apparatus having a power supply. In claim 2 And the power supply outputs a pulsed voltage of a predetermined cycle. In claim 2 The polishing tool has an annular shape, one end of the annular shape constitutes the polishing surface, And the anode member is provided in a non-contact manner inside the ring of the polishing tool, and is rotated and supported together with the polishing tool by the polishing tool rotation support means. In paragraph 4 A cleaning member having a surface for cleaning the surface to be polished on a side opposite to the surface to be polished of the anode member, The cleaning member is formed of a material that absorbs the electrolyte solution and can pass therethrough, and supplies the electrolyte solution supplied from the anode member side to the surface to be polished. In claim 1 And the polishing tool is supported by a conductive cathode member connected to the polishing tool rotation support means and is energized through a conductive brush in contact with the rotating conductive cathode member. A polishing tool having a polishing surface having a polishing surface that rotates and contacts the entire surface of the polished surface of the object to be polished having a copper film on the surface to be polished; On the device Electrolyte solution supply means provided with the scrub member formed from the material which can absorb and let electrolyte pass, and supplies the electrolyte solution containing a chelating agent to the said grinding surface through the said scrub member. Including; A polishing apparatus comprising: an anode electrode and a cathode electrode that are electrically energized on the polishing surface, and planarizes the surface to be polished by electrolytic composite polishing in which electrolytic polishing with the electrolyte and mechanical polishing with the polishing surface are combined. In a polishing apparatus for polishing an object to be polished having a copper film on the surface to be polished Support means for supporting the object to be polished, An electrode plate disposed parallel to the surface to be polished, Excitation means for applying vibration to the object to be polished, An electrolyte solution supply means having a scrub member formed of a material capable of absorbing and passing an electrolyte solution, and supplying an electrolyte solution containing a chelating agent between the surface to be polished and the electrode plate through the scrub member; And an electrolytic current supply means for supplying an electrolytic current flowing from the to-be-polished surface to the electrode plate through the electrolytic solution, using the polishing surface as an anode and the electrode plate as a cathode. In a polishing apparatus for polishing an object to be polished having a copper film on the surface to be polished Support means for supporting the object to be polished, An electrode plate disposed parallel to the surface to be polished, An electrolyte solution supply means having a scrub member formed of a material capable of absorbing and passing an electrolyte solution, and supplying an electrolyte solution containing a chelating agent between the surface to be polished and the electrode plate through the scrub member; And an electrolytic current supply means for supplying an electrolytic current flowing from the to-be-polished surface to the electrode plate through the electrolytic solution, using the polishing surface as an anode and the electrode plate as a cathode. In a polishing apparatus for polishing an object to be polished having a metal film on the surface to be polished Support means for supporting the object to be polished, A wiper for wiping the surface to be polished, An electrolytic solution supply means having a scrub member formed of a material capable of absorbing and passing an electrolytic solution, and for supplying an electrolytic solution to the surface to be polished through the scrub member; An opposite electrode disposed at a position opposite to the surface to be polished, and And current supply means for supplying a current between the surface to be polished and the counter electrode. In a polishing apparatus for polishing an object to be polished having a metal film on the surface to be polished Support means for supporting the object to be polished, A wiper for wiping the surface to be polished, Relative moving means for relatively moving the surface of the object to be polished and the wiper; An electrolytic solution supply means having a scrub member formed of a material capable of absorbing and passing an electrolytic solution, and for supplying an electrolytic solution to the surface of the object to be polished through the scrub member; An opposite electrode disposed at a position opposite to the surface to be polished, and And current supply means for supplying a current between the surface to be polished and the counter electrode.

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