JP2002235188A - Apparatus and method for treatment with liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for treatment with liquid for improving the uniformity of treatment on the treated surface of an object to be treated and the thickness of a deposited film. SOLUTION: Between an injection tube for a treating solution and the object to be treated, there is arranged a micropore board equipped with micropores against the surface to be treated of the object, so that the treating solution jetted from the injection tube is guided to the object through the micropore board. The treating solution flow is straightened by being passed through the micropores and supplied with microperspective uniformity to each part of the surface to be treated. In addition, the rate of perforation of the micropores can be made different according to each part of the micropore board, thereby varying a microperspective electric resistance corresponding to each part of the board between a first and second electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid processing apparatus and a liquid processing method for processing an object to be processed in a liquid phase, and more particularly to improving the uniformity of processing on the processing surface of the object. The present invention relates to a suitable liquid processing apparatus and liquid processing method.

[0002]

2. Description of the Related Art In recent years, a liquid processing step in a semiconductor manufacturing process or a liquid crystal device manufacturing process has been replaced by a reaction process in a gaseous phase due to the miniaturization of processing required for manufacturing a semiconductor device or a liquid crystal device. It is becoming increasingly used.

In such a liquid processing step, it is important to ensure the quality of the processed film and the uniformity of the processed film thickness in the plane of the object to be processed in order to control the quality of the manufactured semiconductor and the like. .

Here, as an example of the liquid processing, a step of performing copper plating on a wafer surface as an object to be processed will be described.

When copper plating is performed on the surface of a wafer to be processed, a conductive seeding layer serving as a cathode for electric field plating and serving as a seed for plating is formed on the surface.

The wafer surface on which the seeding layer has been formed is
For example, it is immersed in a plating solution tank so as to be in contact with a plating solution based on copper sulfate, and from the outer periphery of the wafer, an electric conductor is brought into contact with a seed layer to supply electricity for electrolytic plating. The plating solution tank is provided with a copper anode electrode immersed in the plating solution and containing, for example, phosphorus.

[0007] A flow of the plating solution is created toward the surface of the wafer to be processed immersed in the plating solution bath so that the plating solution containing the active additive is always in contact with the plating solution while maintaining the uniformity in the bath. For this reason, a plating solution jetting pipe is provided in a portion of the plating solution tank facing the surface of the wafer to be processed, and a plating solution jetting pump is provided on an extension at the base of the jetting pipe.

Here, the additive is added so as to promote the plating more uniformly. For example, the additive promotes the plating inside fine grooves and holes formed on the surface of the semiconductor wafer, The wafer surface other than the fine grooves and holes contains components that suppress the formation of plating. The purpose of such an additive is to fill fine grooves and holes with a plating material without voids.

Further, usually, for example, in response to an increase in the plating solution in the plating solution tank due to the ejection of the plating solution, the plating solution overflowing from the plating solution tank is collected, and the plating solution is ejected from the ejection pipe again. A plating solution circulation system that circulates as much as possible is formed.

[0010] In addition, the plating process generates on the anode electrode.
An electrolytic diaphragm is provided between the anode side and the cathode side of the plating bath to prevent the accumulated impurities (called a black film) from peeling off and preventing the plating from being formed on the wafer surface serving as the cathode. Is done.

By using these structures, the plating solution containing the active additive is always supplied into the tank while maintaining the uniformity of the plating solution in the tank, and electricity is supplied between the cathode and the anode. Then, copper is reduced and deposited on the cathode, and copper is formed as plating on the seeding layer.

[0012]

However, in the plating solution tank in which the plating solution flow is generated as described above,
When each part on the entire surface of the wafer is crushed, the flow of the plating solution is not always formed uniformly. This is because even if the uniformity in the tank is ensured as described above, it is only necessary to supply the plating solution containing the active additive to the wafer for the time being to eliminate the flow stagnation.

Therefore, from the viewpoint of further improving the uniformity of the treatment, it is preferable that the flow of the plating solution in the plating solution tank is formed uniformly at each portion on the entire surface of the wafer. According to the improvement of the processing uniformity, the uniformity of the quality of the formed film in the wafer surface can be improved.

The present invention has been made in view of such circumstances, and in a liquid processing apparatus and a liquid processing method for performing processing on a processing object in a liquid phase, the uniformity of processing on the processing surface of the processing object is improved. It is an object of the present invention to provide a liquid processing apparatus and a liquid processing method capable of further improving the performance.

[0015] In addition, the plating layer formed as described above is preferably formed with a more uniform thickness on the wafer surface, mainly in order to facilitate the processing in the subsequent steps. . However, due to the fact that the power for plating is supplied from the outer periphery of the wafer as described above, the plating thickness tends to be thicker at the wafer periphery and thinner at the wafer center. This is because the electrical resistance in the radial direction of the wafer cannot be ignored even though the seeding layer is electrically conductive.

That is, in the power supply for plating, a voltage drop occurs from the outer periphery of the wafer to the center of the wafer. When the potential distribution on the wafer processing surface is viewed from the potential of the anode electrode, the potential difference is larger at the periphery. Become. As a result, a larger current flows due to a larger potential difference at the periphery,
As a result, plating is promoted.

The present invention has been made in view of such circumstances, and in a liquid processing apparatus and a liquid processing method for performing processing on a processing object in a liquid phase, forming a processing object on a processing surface. It is another object of the present invention to provide a liquid processing apparatus and a liquid processing method capable of further improving the uniformity of the film thickness.

[0018]

In order to solve the above-mentioned problems, a liquid processing apparatus according to the present invention is capable of storing first and second processing liquids, and is immersed in the stored second processing liquid. A processing liquid tank including a first electrode to be in a state, a processing object holding mechanism for holding a processing object and bringing a processing surface of the processing liquid into contact with the first processing liquid, and a processing liquid tank provided in the processing liquid tank; The first processing liquid that is in contact with the processing surface and the second processing liquid that immerses the first electrode are separated into electric field diaphragms and provided in the processing liquid tank, and are held by the processing object holding mechanism. A processing liquid ejection pipe for ejecting the first processing liquid toward the processing surface of the object to be processed brought into contact with the first processing liquid;
A contact provided on the processing object holding mechanism and electrically contacting a peripheral portion of the processing object so that a conductive layer of the processing surface brought into contact with the first processing liquid becomes a second electrode; A processing hole is provided between the processing surface of the processing object held by the processing object holding mechanism and brought into contact with the first processing liquid, and the processing liquid ejection pipe, facing the processing surface. And a micro-perforated plate through which the processing liquid jetted from the processing liquid jet pipe is passed and guided toward the processing surface.

Further, the liquid processing apparatus according to the present invention holds a processing liquid tank having a first electrode capable of storing a processing liquid and being immersed in the stored processing liquid, and a processing object. A processing object holding mechanism for contacting the processing surface with the processing liquid; and a processing surface of the processing object provided in the processing liquid tank and held by the processing object holding mechanism and brought into contact with the processing liquid. A processing liquid ejection pipe for ejecting the processing liquid toward the processing object, and the processing target provided in the processing object holding mechanism, wherein the conductive layer on the processing surface contacted with the processing liquid is used as a second electrode. A contact that makes electrical contact with the periphery of the body,
A micropore is provided between the processing surface of the processing object held by the processing object holding mechanism and brought into contact with the processing liquid and the processing liquid ejection pipe, facing the processing surface. And a micro-perforated plate through which the processing liquid jetted from the processing liquid jet pipe is passed and guided toward the processing surface.

A microperforated plate having micropores is disposed between the processing liquid ejection pipe and the object to be processed, facing the processing surface of the object to be processed. Thus, the processing liquid spouted from the processing liquid spouting pipe is guided to the object through the fine hole plate. Fine holes are arranged in the micro-perforated plate, and the processing liquid passes through the fine holes to regulate the liquid flow, and the processing liquid is uniformly and microscopically supplied to each part of the processing surface. Become like

Therefore, it is possible to further improve the uniformity of the processing on the processing surface of the object to be processed.

Further, by making the aperture ratio of the micropores different for each portion of the micropore plate, a microscopic portion corresponding to each portion of the micropore plate between the first electrode and the second electrode can be obtained. The electrical resistance depends on the aperture ratio. This is because the processing liquid passing through the opening has conductivity, but the microporous plate itself can be made non-conductive. The electric resistance is changed depending on the aperture ratio, and thereby, it becomes possible to control the magnitude of the processing current during the processing for each part on the surface of the object to be processed.

Therefore, it is possible to further improve the uniformity of the formed film thickness on the processing surface of the object to be processed.

Further, a liquid processing method according to the present invention is a liquid processing method using a liquid processing apparatus having the above-mentioned features, wherein the step of holding the object to be processed by the object holding mechanism is performed. Contacting the held object to be processed with the (first) processing liquid;
A) the first electrode and the second electrode while ejecting the (first) treatment liquid from the treatment liquid ejection pipe through the microperforated plate toward the object to be contacted with the treatment liquid; And performing a liquid treatment by applying an electric field between the two.

Therefore, as described above, it is possible to further improve the uniformity of the processing on the processing surface of the object to be processed. Further, it is possible to further improve the uniformity of the formed film thickness on the processing surface of the object to be processed.

[0026]

As a preferred embodiment of the present invention, in the liquid processing apparatus according to claim 1 or 2, the microperforated plate is made of porous ceramics. It can be prepared most easily as a microporous plate. The pore diameter of the fine pores in the porous ceramics can be, for example, about 5 μm to 200 μm.

Also, as a preferred embodiment of the present invention,
3. The liquid processing apparatus according to claim 1, wherein the microporous plate has a fine honeycomb structure. The fine honeycomb structure is suitable as a microporous plate. The arrangement pitch of the honeycomb can be, for example, about 20 μm to 500 μm.

Further, as a preferred embodiment of the present invention,
3. The liquid processing apparatus according to claim 1, wherein the fine holes are present in a direction substantially perpendicular to a processing surface of the object to be processed. Since the micropores are substantially perpendicular to the processing surface, the liquid flow is not diffused and easily guided to the processing surface.

Further, as a preferred embodiment of the present invention,
3. The liquid processing apparatus according to claim 1, wherein in the microporous plate, the existence density of the micropores is lower as the portion of the object to be processed is closer to the periphery of the object. The electrical resistance between the electrodes can be increased by reducing the density of the micropores.

Further, as a preferred embodiment of the present invention,
3. The liquid processing apparatus according to claim 1, wherein the fine hole plate has a smaller fine hole diameter in a portion facing the periphery of the object to be processed closer to the peripheral portion. The electrical resistance between the electrodes can be increased by reducing the diameter of the fine holes.

Further, as a preferred embodiment of the present invention,
3. The liquid processing apparatus according to claim 1, wherein the microperforated plate includes a plurality of sections, and each of the microperforated plates in the section has a finer hole as it faces closer to the periphery of the object to be processed. 4. Density is low. The microporous plate is made up of a plurality of sections to make it easier to manufacture, and by reducing the density of the micropores, it is possible to increase the microscopic electrical resistance between the electrodes at that portion.

Further, as a preferred embodiment of the present invention,
3. The liquid processing apparatus according to claim 1, wherein the microperforated plate includes a plurality of sections, and each of the microperforated plates in the section has a finer hole as it faces closer to the periphery of the object to be processed. 4. Hole diameter is small. The microporous plate is made up of a plurality of sections to make it easier to manufacture, and by reducing the diameter of the micropores, the microscopic electrical resistance between the electrodes can be increased at that portion.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a front sectional view showing a schematic configuration of a liquid processing apparatus according to an embodiment of the present invention. FIG. 1 exemplifies, as a liquid processing apparatus, a plating apparatus which forms wirings and vias between wirings by plating on the surface of a semiconductor wafer as an object to be processed. As shown in FIG. 1, this plating apparatus is entirely covered with a housing 12 having a closed structure. The housing 12 is made of a plating liquid resistant material such as a synthetic resin.

The interior of the housing 12 has a structure in which the first processing unit is located at the upper and lower stages, that is, the first processing unit is located at the lower stage and the second processing unit is located at the upper stage. The first processing unit and the second processing unit are separated by a separator having a cleaning nozzle 23 and an exhaust port 22 provided below the cleaning nozzle 23. A through hole is provided at the center of the separator so that the wafer 21 held by the wafer holding unit 17 can move between the first processing unit and the second processing unit. A plurality of cleaning nozzles 23 are provided in the circumferential direction of the through hole.

A gate valve 18 for loading / unloading the wafer 21 into / from the plating apparatus is provided in the housing 12 which is slightly above the boundary between the first processing section and the second processing section.
Is provided. When the gate valve 18 is closed, the inside of the plating apparatus becomes a space isolated from the space outside the plating apparatus, so that the diffusion of dirt from the plating apparatus into the outside space is prevented.

A plating solution tank 24 as a processing solution tank is provided inside the first processing section. This plating solution tank 24
Is provided with an outer tank 25 arranged concentrically on the outside thereof. When the plating solution tank 24 is filled with the plating solution,
The plating solution tank 2 is arranged such that the surface to be plated of the wafer 21 at a plating position (IV) described later is lower than the plating solution level.
4 is fixed.

The plating solution tank 24 is formed in a substantially cylindrical shape with a bottom, and the opening surface of the plating solution tank 24 is maintained substantially horizontal. The plating bath 2 is provided inside the plating bath 24.
An ejection pipe 29 serving as a processing liquid ejection pipe for ejecting a plating solution from the bottom side of the plating solution 4 toward the upper surface thereof protrudes from substantially the center of the bottom surface of the plating solution tank 24 to almost the middle in the depth direction of the plating solution tank 24. An anode electrode 27 as a substantially disk-shaped first electrode is provided around the ejection pipe 29.
By dissolving this anode electrode 27 in a plating solution containing, for example, copper sulfate, the concentration of copper ions in the plating solution is kept constant.

A lead wire is extended from the anode electrode 27 to an external power source (not shown) outside the outer tank 25. When the power source is turned on, an electric field is generated between the anode electrode 27 and the wafer 21. Is formed.

Between the outer periphery of the end of the jet pipe 29 and the plating solution tank 24, a diaphragm 26 as an electrolytic diaphragm for partitioning the plating solution tank 24 up and down is provided above the anode electrode 27. The ejection pipe 29 is provided above the plating solution tank 24 (hereinafter, referred to as “above the plating solution tank”).
Supplies a plating solution as a first processing solution from the
A plating solution as a second processing solution is supplied to the lower side of the plating solution tank 24 (hereinafter, referred to as “the lower side of the plating solution tank”) partitioned by 6 from a circulation pipe 28 described later. ing. The diaphragm 26 transmits ions, but does not transmit impurities generated when the anode electrode 27 is dissolved and bubbles such as oxygen and hydrogen generated during plating on the surface to be plated of the wafer 21. It is configured. In the present invention, this function may be substituted for the microperforated plate 33 without providing the electric field diaphragm 26.

Slightly above the middle of the plating solution tank 24 in the depth direction, a microperforated plate 33 is separated from the diaphragm 26 by a certain distance.
It is provided so as to face a wafer 21 held by a wafer holding unit 17 described later. The plating solution ejected from the ejection pipe 29 flows between the diaphragm 26 and the microperforated plate 33 and is guided to each of the fine holes present in the microperforated plate 33,
As a result, the flow is parallel to the vertical direction of the plating solution tank 24 and is supplied to the wafer 21. Even when the diaphragm 26 is not provided, the plating solution spouted from the spouting tube 29 is not
There is no change in that it enters from the lower surface of 3 and is guided upward.

Circulation pipes 28 and 30 are provided at positions eccentric from the center of the bottom surface of the plating solution tank 24, and a pump (not shown) is provided between the circulation pipes 28 and 30. By operating this pump, the plating solution is circulated below the plating solution tank 24. Such a circulation may be performed when the diaphragm 26 is not provided.

The outer tank 25 is formed in a substantially cylindrical shape with a bottom like the plating solution tank 24, and the opening surface of the outer tank 25 is maintained substantially horizontal. The bottom of the outer tank 25 has two outlets.
The outlet 32 is connected to a pipe 32. A pump 31 is provided between the pipe 32 and the ejection pipe 29. A tank (not shown) containing a plating solution is connected to the pipe 32 via a pump and a valve, and the pump is operated to open the valve so that the plating solution in the tank is removed from the plating solution tank 24. Can be supplied.

On the other hand, inside the second processing section, the wafer 2
Wafer Holder 1 as Workpiece Holder Holding Object 1
7 is disposed right above the center of the plating solution tank 24. The wafer holder 17 is suspended by a motor 14 that rotates the wafer 21 together with the wafer holder 17 in a substantially horizontal plane.

The motor 14 is covered with a cover made of a plating liquid-resistant material such as a synthetic resin, and prevents the mist from evaporating and scattered plating liquid from entering the motor 14. ing.

A support beam 13 for supporting the motor 14 is mounted outside the motor 14. An end of the support beam 13 is attached to an inner wall of the housing 12 via a guide rail 15 so as to be able to move up and down. The support beam 13 is further attached to the housing 12 via a vertically expandable and contractible cylinder 11. By driving the cylinder 11, the motor 1 supported by the support beam 13 is moved.
4 and the wafer support 17 move up and down along the guide rail 15 to move the wafer 21 up and down.

This vertical movement is, specifically, when the wafer 21 placed on the wafer holding unit 17 is moved between the loading / unloading position (I) for carrying and the plating surface of the wafer 21 by, for example, pure movement. A cleaning position (II) for performing a cleaning process with a cleaning liquid such as water, a spin dry position (III) for performing a spin dry described later, and a plating process for forming a plating layer on a surface to be plated of the wafer 21. It is performed so as to move up and down between the position (IV). The loading / unloading position (I) and the cleaning position (II) are above the plating solution level when the plating solution is filled up in the plating solution tank 24, and the spin dry position (III) and the plating position (IV) ) Is below the level of the plating solution.

The wafer holder 17 is formed in a substantially cylindrical shape, and can hold one wafer 21 substantially horizontally inside the wafer holder 17. A substantially circular opening is formed in the bottom surface of the wafer holding unit 17, and a plating layer can be formed on the surface of the wafer 21 held inside the wafer holding unit 17, which is to be plated as a second electrode. I can do it.

The wafer 21 held by the wafer holder 17
A thin film of copper, a so-called seed layer, is previously formed on another surface of the wafer 21 by another apparatus, and a voltage applied to a cathode contact member described later is also applied to the surface of the wafer 21 to be plated. ing.

Further, the wafer holding section 17 is provided with a wafer pressing mechanism 19 and a contact / seal presser 20. The back surface of the wafer 21 placed on the wafer holding unit 17 is pressed by the wafer pressing mechanism 19 to ensure electrical contact between the wafer 21 and the contacts.
The wafer pressing mechanism 19 is disposed so as to be able to uniformly press the wafer 21 toward the outer periphery in the circumferential direction, and moves up and down independently of the wafer holding unit 17.

The contact / seal presser 20 presses and fixes a cathode contact member and a seal member, which will be described later, to the wafer holding section 17. The contact / seal retainer 20 is disposed so as to coincide with the circumferential direction of the wafer holding unit 17.

Further, a vacuum chuck 16 is provided at the center of the cylinder of the wafer holder 17 so that the wafer 21 can be lifted from the bottom surface of the wafer holder 17 when cleaning contacts. The vacuum chuck 16 can move up and down independently of the wafer holding unit 17.

A seal member described later is provided at the opening edge inside the wafer holding portion 17, and the plating solution can be prevented from entering the inside of the wafer holding portion 17 by the seal member and the above-mentioned pressing.

Next, details of the mounting state of the wafer 21 on the wafer holder 17 in the plating apparatus of this embodiment will be described with reference to FIG. FIG. 3 is a schematic front sectional view for explaining a state where the wafer 21 is placed on the wafer holding unit 17. The components already described in FIG. 2 are denoted by the same reference numerals.

As shown in FIG. 2, the wafer holding section 17
A cathode contact member 52 as a contact for applying a voltage to the surface to be plated of the wafer 21 is provided inside the side member 17a and the bottom member 17b. This cathode contact member 52 is
It is formed of a conductive material, and includes a portion formed in a ring shape in the circumferential direction of the wafer holding portion 17 and a contact portion formed by projecting from this portion.

The contact portion has at least one ring-shaped portion.
More than one part is formed integrally. Further, it is preferable that the number of contact portions in all the circumferential directions of the wafer is 6 to 180. The reason for this is that, for example, a wafer 2 having a diameter of 30 cm
This is because if the number exceeds 1, even if the number exceeds 180, deficiencies in processing are likely to occur in production, and if the number is less than the above range, the plating current distribution on the surface to be plated of the wafer 21 becomes difficult to be uniform.

The cathode contact member 52 is connected to a lead wire so that a voltage can be applied from an external power supply (not shown) via the lead wire.

The contact portion of the wafer 21 with the contact member 52 is sealed by a seal member 51 to prevent the plating solution from entering. The seal member 51 is used for the wafer holder 1.
7 are arranged in a ring shape in the circumferential direction, and project in a ring shape in a direction facing the wafer 21. The seal member 51 is made of, for example, rubber having elasticity, and
The back surface of the wafer 21 is elastically deformed by being pressed downward by the wafer pressing mechanism 19 to ensure the sealing property between the wafer 21 and the surface to be plated.

Next, the microperforated plate 33, which is a feature of the present invention, used in the above-described embodiment will be further described with reference to FIG. FIG. 3 is a partial sectional view from the front showing an example of a microperforated plate that can be used in the embodiment shown in FIGS.

The microporous plate 33a shown in FIG. 3 is made of porous ceramics, and the direction in which the holes are formed is vertical in the drawing. When the plating solution passes through the holes formed in the vertical direction from the bottom to the top, the flow of the plating solution becomes parallel and is supplied to the surface to be plated of the wafer. Therefore, the plating liquid ejected from the ejection pipe has a uniform flow, and the plating liquid is supplied microscopically and uniformly to each portion of the surface to be plated. This makes it possible to further improve the uniformity of processing on the surface to be plated of the wafer.

The lower surface of the microperforated plate 33a is substantially parallel to the diaphragm 26 when disposed in the plating solution tank 24, corresponding to the fact that the diaphragm 26 has a cone shape as shown in FIG. It is also formed in a cone shape to keep Thereby, the plating solution ejected from the ejection pipe 29 flows more smoothly. Further, even when impurities are mixed in the plating solution, there is an effect that the impurities are caused to flow toward the inner wall side of the plating solution tank 24 and hardly adhere to the lower surface of the fine hole plate 33a.

The material of the porous ceramics is as follows.
For example, in consideration of acid resistance ₂O₃Etc.
be able to. The diameter of the formed hole is
To impede the filtering effect and add liquid
About 5μm to 200μm considering the ease of flow
It is preferable to set the temperature. In addition, viewed in the cross-sectional direction of the hole
The aperture ratio of all the fine holes with respect to the cross-sectional area of the whole fine hole plate is
Considering the amount of liquid to be supplied and its ease of passage,
It can be set from 0% to 90%.

Next, still another example of the microperforated plate 33 will be described with reference to FIG. FIG. 4 is a plan view showing another example of the fine hole plate that can be used in the embodiment shown in FIGS.

The microporous plate 33b shown in FIG. 4 has a fine honeycomb structure as shown in FIG. Such a microperforated plate in which holes having a fine honeycomb structure are formed in a direction perpendicular to the plane of the paper of the drawing also causes the plating solution to be ejected from the jet tube in the same manner as the microperforated plate 33a shown in FIG. Is obtained.

Therefore, by using such a microporous plate 33b, the plating solution can be microscopically and uniformly supplied to each part of the surface to be plated. Can be further improved.

The material of the microporous plate 33b is, for example, Al ₂ O ₃ in consideration of acid resistance and workability.
O _{3 and the} like can be mentioned. Further, in order to form a fine honeycomb structure using these materials, a manufacturing method such as corrugation can be used. Further, the diameter of the formed hole is preferably about 20 μm to 500 μm in consideration of the fact that a bubble or the like is impervious to add a filtering effect, the ease of liquid flow, and the like. In addition, the opening ratio of all the holes with respect to the entire cross-sectional area of the micro-perforated plate 33b viewed in the cross-sectional direction of the holes is set to 10% to 90% in consideration of the amount of liquid to be supplied and its ease of passage. be able to. The pitch of the holes is about 20 μm to 500 μm.

Next, the microperforated plate 33 shown in FIGS.
Modifications of a and 33b will be described with reference to FIGS. FIG. 5 and FIG. 6 are graphs showing the change in the density of existing fine holes or the change in the hole diameter from the center to the peripheral edge of the fine hole plate as a modification.

In the microporous plate having the distribution of the micropore existence density as shown in FIG. 5, the micropore existence density is high at the center and therefore the aperture ratio is high. The aperture ratio is low.

When such a microporous plate is used, the wafer 2
As compared with the liquid electric resistance of the plating solution from the anode electrode 27 to the central portion of the surface 1 to be plated, the liquid electric resistance from the anode electrode 27 can be increased toward the peripheral portion. This is because the microscopic cross section of the plating solution in the microporous plate portion in the direction perpendicular to the electric field during plating is different.

By changing the liquid resistance in this way, it is possible to control the magnitude of the processing current during the plating process for each part on the wafer surface. In other words, it is possible to realize a smaller current for the peripheral portion of the wafer and a larger current for the central portion of the wafer. As a result, a current can be applied to each part of the wafer so as to cancel the unevenness of the formed film thickness due to the electric resistance of the seed layer. Therefore, it is possible to further improve the uniformity of the formed film thickness on the surface to be plated of the wafer.

In order to obtain such a fine hole existence density distribution in a fine hole plate, it is more suitable to use porous ceramics as shown in FIG.

The microporous plate having the distribution of the fine holes as shown in FIG. 6 has a large hole diameter at the center and therefore a high aperture ratio, and has a small hole diameter toward the periphery so that the hole ratio is small. Is low.

Even when such a micro-perforated plate is used, as in the case of the micro-perforated plate having the structure shown in FIG. As compared with the resistance, the liquid electric resistance from the anode electrode 27 can be increased toward the peripheral portion.

That is, it is possible to realize a smaller current at the peripheral portion of the wafer and a larger current at the central portion of the wafer. As a result, a current can be applied to each part of the wafer so as to cancel the unevenness of the formed film thickness due to the electric resistance of the seed layer. Therefore,
It is possible to further improve the uniformity of the formed film thickness on the surface to be plated of the wafer.

In order to obtain such a pore size distribution in a microporous plate, it is possible to use a porous ceramics as shown in FIG. 3 or a fine honeycomb structure as shown in FIG. Can also be used. In the case of using a honeycomb structure, the hole diameter becomes smaller when the pitch is made uniform and the nest wall thickness is increased, and the hole diameter is increased when the nest wall thickness is reduced.

Next, the microperforated plate 33 shown in FIGS.
Another modified example of a and 33b will be described with reference to FIG. FIG. 7 is a plan view showing a microperforated plate as another modification (FIG. 7 (a)), and a graph showing a change in the density of micropores from the center to the periphery of the microperforated plate (FIG. 7). (B)).

As shown in FIG. 7 (a), the microperforated plate 33c is composed of concentrically different members 61, 62 and 63. The difference between the members 61, 62 and 63 is shown in FIG.
As shown in (1), the density of micropores is different. The center member 63 has the highest density of micropores, and the edge member 61 has the lowest density of micropores.

In other words, the microperforated plate 33c can be said to have the microperforated plate described in FIG. 5 in which the microporous density is not continuously changed but roughly three. By configuring the microperforated plate 33c so as to have such a discrete density of micropores, the microscopic current distribution on the surface to be processed of the wafer is improved.

Therefore, it is possible to supply a current to each part of the wafer so as to cancel the nonuniformity of the formed film thickness due to the electric resistance of the seed layer. Performance can be further improved.

The three members 61, 62,
With the configuration of 63, each can be processed into a predetermined shape and then combined to form a microperforated plate, which facilitates production of a microperforated plate having a change in the density of micropores. In addition, the number of members is not limited to three, and if the number is increased, it is possible to obtain a more continuous distribution of the density of micropores.

Next, the microperforated plate 33 shown in FIGS.
Still another modified example of a and 33b will be described with reference to FIG. FIG. 8 is a plan view (FIG. 8A) showing a microperforated plate as still another modified example, and a graph showing a change in the hole diameter of the micropores from the center to the periphery of the microperforated plate (FIG. 8). (B)).

As shown in FIG. 8A, the microperforated plate 33d is composed of members 71, 72 and 73 which are concentrically different. The difference between the members 71, 72 and 73 is shown in FIG.
The central member 73 has the largest diameter of the fine holes, and the edge member 71 has the largest diameter.
Has the smallest pore diameter.

That is, it can be said that the fine hole plate 33d is obtained by changing the fine hole diameter distribution of the fine hole plate described with reference to FIG. By configuring the microperforated plate 33d so as to have such a discrete micropore diameter distribution, the microscopic current distribution on the surface to be processed of the wafer is improved.

Therefore, the microperforated plate 33c shown in FIG.
In the same manner as described above, current can flow through each part of the wafer so as to cancel the nonuniformity of the formed film thickness caused by the electric resistance of the seed layer. Can be further improved.

The three members 71, 72,
By configuring the micropores 73, each can be processed into a predetermined shape and then combined to form a microperforated plate, which facilitates production as a microperforated plate having a change in the hole diameter of the micropores. In addition, the number of members is not limited to three, and if the number is increased, a more continuous micropore diameter distribution can be obtained.
These are the same as the microperforated plate 33c shown in FIG.

The microperforated plates 33c, 33 shown in FIGS.
In addition to the example of d, the existence density of the micropores and the diameter of the micropores may be changed as a relationship between the plurality of portions.

Next, the operation of the plating apparatus according to the embodiment of the present invention having the above-described configuration will be described with reference to FIG. FIG. 6 is a flowchart showing an operation flow of the plating apparatus according to the embodiment of the present invention.

First, the gate valve 18 provided on the side wall of the plating apparatus is opened, the arm carrying the unprocessed wafer is extended, and the wafer holding unit which waits for the wafer at the loading / unloading position (I). 17, the surface to be plated of the wafer 21 is placed substantially horizontally toward the surface of the plating solution containing copper sulfate, for example. Here, in detail, the wafer holding unit 17 receives the wafer 21 so as to be placed on the contact point of the contact member 52 as shown in FIG. 2 (Step 81).

After placing the wafer 21 on the contact member 52, the arm is retracted to close the gate valve 18, and the wafer pressing mechanism 1 provided in the wafer holder 17.
9 presses the back surface of the wafer 21 (step 8).
2). At this time, the plating solution tank 24 is filled with the plating solution. Due to this pressing, the protrusion of the seal member 51 is surely elastically deformed to generate a compressive stress and repel the contacting wafer 21, thereby preventing the plating solution from entering the inside of the wafer holding portion 17.

Thereafter, while maintaining this sealed state,
The wafer holding unit 17 is lowered by driving the cylinder 11 to position the wafer 21 at the plating position (IV). Thereafter, a voltage is applied between the anode electrode 27 and the cathode contact member 52, and the wafer 21 is covered. The plating surface is plated with, for example, copper (step 83).

During the plating process, the wafer holding unit 17 rotates to improve the processing non-uniformity of the wafer 21 caused by the plating solution flow. In addition, a plating solution flow is formed on the surface to be plated of the wafer 21 through the fine hole plate 33, and the plating solution is supplied microscopically and uniformly to each of the portions. Therefore, it is possible to further improve the uniformity of processing on the surface of the wafer 21 to be plated.

After a plating layer having a sufficient thickness is formed on the surface to be plated of the wafer 21, the application of the voltage is stopped. And
A predetermined amount of the plating solution is returned to a tank (not shown), and the level of the plating solution in the plating solution tank 24 is lowered. After lowering the level of the plating solution, the wafer holding unit 17 is raised by driving the cylinder 11 to move the wafer 21 to the spin dry position (III).
Position.

In this state, the wafer holder 17 is
Then, the substrate is rotated in a substantially horizontal plane and spin-dried to remove excess plating solution adhering to the plating surface of the wafer 21 (step 84).

After spin-drying is sufficiently performed, the wafer holding unit 17 is raised by driving the cylinder 11, and
Is located in the washing position (II). In this state, the wafer holding unit 17 is rotated in a substantially horizontal plane by the driving of the motor 14 and the cleaning nozzle 23 built in the separator is rotated.
Then, pure water is sprayed toward the plating layer forming surface of the wafer 21 to wash and dry the plating layer forming surface of the wafer 21 (step 85).

After the cleaning of the plating layer forming surface of the wafer 21 is completed, the pressing by the wafer pressing mechanism 19 is stopped while the wafer holding unit 17 is maintained at that position. Then, the vacuum chuck 16 that raises and lowers the wafer 21 sucks and raises the back surface of the wafer 21 (step 86).

With the wafer 21 raised, only the wafer holder 17 is rotated by the drive of the motor 14, and
For example, pure water as a cleaning liquid is spouted from the cleaning nozzle 23 incorporated in the separator toward the contact member 52 to be cleaned, and dried by rotation (step 8).
7). (Note that the wafer 21 may be dried by rotation.)

Thereafter, the wafer holder 17 is moved to the cylinder 11
And the wafer 21 is loaded and unloaded at the loading / unloading position (I).
And unloads the wafer 21 (step 88).

[0098] Between step 87 and step 88, the wafer holding unit 17 may be lowered to the spin dry position (III) to spin dry the wafer 21. At this time, air may be flown over the contact member 52 by an air supply device (not shown) to completely remove moisture.

In the above description, a plating apparatus for plating a wafer has been described as an example of a liquid processing apparatus. However, the present invention can be applied to a non-circular substrate such as a liquid crystal device substrate.

[0100]

As described in detail above, according to the present invention,
Since a micro-perforated plate having micro holes is disposed between the processing liquid ejection pipe and the object to be processed, facing the processing surface of the object to be processed, the processing liquid ejected from the processing liquid ejection pipe is provided with fine holes. The processing liquid is guided to the object to be processed through the plate, and the processing liquid passes through the fine holes, so that the liquid flow is adjusted, and the processing liquid is uniformly and microscopically supplied to each part of the processing surface. . Therefore, it is possible to further improve the uniformity of processing on the processing surface of the processing target.

Further, by making the aperture ratio of the micropores different for each portion of the micropore plate, a microscopic portion corresponding to each portion of the micropore plate between the first electrode and the second electrode can be obtained. It is possible to control the magnitude of the processing current during processing for each part on the surface of the processing object by changing the electrical resistance. Therefore, it is possible to further improve the uniformity of the formed film thickness on the processing surface of the object to be processed.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a schematic configuration of a liquid processing apparatus according to an embodiment of the present invention.

FIG. 2 is a view showing a state where a wafer 21 is inserted into a wafer holding unit 17 in FIG.
FIG. 2 is a schematic front cross-sectional view for explaining a mounting state of FIG.

FIG. 3 is a partial cross-sectional view from the front showing an example of a fine hole plate that can be used in the embodiment shown in FIGS. 1 and 2;

FIG. 4 is a plan view showing another example of the fine hole plate that can be used in the embodiment shown in FIGS. 1 and 2;

FIG. 5 is a graph showing the density of micropores from the center to the periphery of a micropore plate as a modification.

FIG. 6 is a graph showing a change in the hole diameter of a fine hole from a center to a peripheral portion of a fine hole plate as a modified example.

7A is a plan view showing a microperforated plate as another modified example, and FIG. 7B is a graph showing a change in the density of micropores from the center to the periphery of the microperforated plate.

FIG. 8A is a plan view showing a microperforated plate as still another modified example, and FIG. 8B is a graph showing a change in the hole diameter of the micropores from the center to the periphery of the microperforated plate.

FIG. 9 is a flowchart showing an operation flow of a plating apparatus as a liquid processing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

11 ... Cylinder 12 ... Housing 13 ... Support beam 1
DESCRIPTION OF SYMBOLS 4 ... Motor 15 ... Guide rail 16 ... Vacuum chuck 17 ... Wafer holding part 17a ... Side member 17b ... Bottom member 18 ... Gate valve 19 ... Wafer pressing mechanism 20
... Contact / Seal Holder 21 ... Wafer 22 ... Exhaust Port 23 ... Cleaning Nozzle 24 ... Plating Solution Tank 25 ... Outer Tank 26 ... Diaphragm 27 ... Anode Electrode 28, 30 ... Circulation Piping 29 ... Squirting Pipe 31 ... Pump 32 ... Piping 33, 33
a, 33b, 33c, 33d: Microporous plate 51: Seal member 52: Cathode contact member 61, 62, 6
3, 71, 72, 73...

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K024 AA09 AB01 AB06 BB12 BC10 CA10 CB13 CB16 CB26 GA02 4M104 BB04 CC01 DD06 DD52 FF13 FF22 HH20

Claims (11)

[Claims] 1. A processing liquid tank having a first electrode capable of storing first and second processing liquids and being immersed in the stored second processing liquid, and holding an object to be processed. An object holding mechanism for bringing the processing surface into contact with the first processing liquid; and a dipping means for the first electrode provided in the processing liquid tank and contacting the processing surface with the first electrode. An electrolytic diaphragm that separates the second processing liquid from the processing liquid; and is provided in the processing liquid tank, and is held by the processing object holding mechanism and directed toward the processing surface of the processing object contacted with the first processing liquid. A processing liquid jetting pipe for jetting the first processing liquid, and a conductive layer on the processing surface, which is provided in the processing object holding mechanism and is brought into contact with the first processing liquid, is used as a second electrode. A contact that makes electrical contact with the peripheral portion of the object to be processed, The processing liquid ejecting pipe is provided between the processing surface of the object to be processed brought into contact with the first processing liquid and the processing liquid ejecting pipe so as to face the processing surface, and provided with a fine hole. A micro-perforated plate for passing the processing liquid ejected from the tube and guiding it toward the processing surface. 2. A processing liquid tank having a first electrode capable of storing a processing liquid and being immersed in the stored processing liquid; and a processing object holding a processing object and changing a processing surface thereof to the processing liquid. A processing object holding mechanism to be brought into contact with the processing liquid, the processing liquid being ejected toward the processing surface of the processing object provided in the processing liquid tank and held by the processing object holding mechanism and brought into contact with the processing liquid; A processing liquid ejection pipe, provided in the processing object holding mechanism, and electrically contacting a peripheral portion of the processing object so that the conductive layer on the processing surface brought into contact with the processing liquid becomes a second electrode. A contact, provided between the processing surface of the processing object, which is held by the processing object holding mechanism and brought into contact with the processing liquid, and the processing liquid ejection pipe, facing the processing surface; The processing liquid ejected from the processing liquid ejection pipe by being provided Liquid processing apparatus characterized by having a fine pore plate is passed through guides on the treated surface direction. 3. The liquid processing apparatus according to claim 1, wherein the microporous plate is made of porous ceramics. 4. The liquid processing apparatus according to claim 1, wherein the microporous plate has a fine honeycomb structure. 5. The liquid processing apparatus according to claim 1, wherein the fine holes are present in a direction substantially perpendicular to a processing surface of the object to be processed. 6. The liquid processing apparatus according to claim 1, wherein the micropore plate has a lower density of micropores as it faces closer to the peripheral edge of the object to be processed. 7. The liquid processing apparatus according to claim 1, wherein the fine hole plate has a smaller hole diameter at a portion facing the periphery of the object to be processed nearer to the periphery. 8. The microperforated plate includes a plurality of sections,
3. The liquid processing apparatus according to claim 1, wherein, in each of the microporous plates in the section, the density of the micropores is lower as the plate is closer to the periphery of the object to be processed. 4. 9. The microperforated plate includes a plurality of sections,
3. The liquid processing apparatus according to claim 1, wherein each of the micro-perforated plates in the section has a smaller micro-hole diameter as it faces closer to the peripheral portion of the object to be processed. 4. 10. A method for receiving first and second processing liquids,
A processing solution tank having a first electrode that is immersed in the second processing solution contained therein, and a processing object holding that holds the processing object and contacts a processing surface of the processing object to the first processing liquid A mechanism, provided in the processing liquid tank, for separating the first processing liquid in contact with the processing surface and the second processing liquid for immersing the first electrode into an electrolytic diaphragm and the processing liquid tank; A processing liquid ejection pipe provided for ejecting the first processing liquid toward a processing surface of the processing object that is held by the processing object holding mechanism and brought into contact with the first processing liquid; A contact provided on the processing body holding mechanism and electrically contacting a peripheral portion of the processing target so that the conductive layer on the processing surface brought into contact with the first processing liquid is used as a second electrode; The object to be processed held by the processing object holding mechanism and brought into contact with the first processing liquid A processing liquid ejected from the processing liquid ejection tube is provided between the processing surface and the processing liquid ejection pipe so as to face the processing surface, and has a fine hole to guide the processing liquid toward the processing surface. A liquid processing method using a liquid processing apparatus having a microporous plate, wherein the processing target holding mechanism holds a processing target to be processed, and the held processing target is subjected to the first processing. Contacting the first processing liquid with the first processing liquid while causing the first processing liquid to be ejected from the processing liquid ejection pipe through the fine hole plate to the object to be contacted with the first processing liquid; Applying an electric field between an electrode and the second electrode to perform liquid treatment. 11. A processing liquid tank having a first electrode capable of storing a processing liquid and being immersed in the stored processing liquid, and holding a processing target and setting a processing surface of the processing liquid to the processing liquid. An object-to-be-processed holding mechanism to be brought into contact with the processing solution tank,
A processing liquid ejection pipe for ejecting the processing liquid toward a processing surface of the processing object held by the processing object holding mechanism and brought into contact with the processing liquid, and provided in the processing object holding mechanism; A contact that makes electrical contact with a peripheral portion of the processing object so that the conductive layer on the processing surface brought into contact with the processing liquid becomes a second electrode; and a contact that is held by the processing object holding mechanism and contacts the processing liquid. The processing liquid ejected from the processing liquid ejection pipe is provided between the processing surface of the object to be processed and the processing liquid ejection pipe by being provided opposite to the processing surface and having a fine hole. A liquid processing apparatus using a liquid processing apparatus having a micro-perforated plate guided in the processing surface direction, wherein the processing target holding mechanism holds a processing target to be processed; and Bring the processing body into contact with the processing solution And, between the first electrode and the second electrode while ejecting the treatment liquid from the treatment liquid ejection pipe through the fine hole plate to the object to be contacted with the treatment liquid. Applying an electric field to the liquid to perform liquid processing.