KR100751102B1 - Electroless plating apparatus and method - Google Patents

Abstract

The electroless plating solution is divided into a first chemical solution containing a metal salt and a second chemical solution containing a reducing agent. In each chemical supply path, an opening and closing means for the chemical solution is provided near the confluence point, and the electroless plating solution is supplied after joining. A plating liquid opening and closing means is provided in the vicinity of the discharge port in the furnace, and the plating liquid in the supply passage disposed between these opening and closing means corresponds to the discharge amount required for approximately one plating treatment, and the plating treatment of one substrate is performed. It is initiated to allow both chemicals to be mixed only until the next substrate treatment is started.

Electroless plating solution, electroless plating apparatus, damascene process, semiconductor substrate, electroless plating method

Description

Electroless Plating Apparatus and Method {ELECTROLESS PLATING APPARATUS AND METHOD}

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal side view showing the overall configuration of an embodiment of an electroless plating apparatus according to the present invention.

2 is a schematic configuration diagram showing a main part of the electroless plating apparatus.

3A to 3C are explanatory views showing the surface structure of the wafer used for the electroless plating process.

4A and 4B are explanatory views showing the state at the time of performing a process with respect to a wafer by said electroless-plating apparatus.

5A and 5B are explanatory views showing the state at the time of performing a process with respect to a wafer by said electroless-plating apparatus.

6A and 6B are explanatory views showing the state at the time of performing a process with respect to a wafer by said electroless-plating apparatus.

7A and 7B are schematic side views showing a modification of the structure near the confluence point of the first chemical liquid supply passage and the second chemical liquid supply passage in the above embodiment.

8 is a perspective view showing an outline of a main part according to another embodiment of the present invention.

FIG. 9 is a longitudinal side view schematically showing the inside of the upper temperature regulator shown in FIG. 8. FIG.

Explanation of symbols for the main parts of the drawings

11... Wafer chuck

12... End

16... Inclined mechanism

17,18... Nozzle

21... cup

3... Upper Thermostat

30... Moving mechanism

31... Flow room

41... With electroless plating solution supply

42... Outlet

43.. valve

5... First chemical supply path

51... valve

6... 2nd chemical liquid supply passage

61... valve

71... Pure supply furnace

73... valve

302... Copper wiring

304... Catalyst layer made of palladium

305... Electroless plating film

* Patent Document 1: Japanese Patent Publication 2004-107747 (FIG. 1 and Paragraph 0026)

The present invention relates to an electroless plating apparatus and method for supplying an electroless plating solution onto a substrate to plate the surface of the substrate, for example, the surface of the wiring metal of the semiconductor substrate.

The multilayer structure of a semiconductor device is comprised by laminating | stacking the layer which embedded the wiring in the interlayer insulation film in multiple steps. Copper is used as a preferred wiring material that is resistant to electron transfer (electromigration), and as a method of forming the wiring, a recess including a groove is formed in the interlayer insulating film, and the copper is embedded after filling the recess with the recess. A damascene process for polishing copper by a polishing method called CMP is employed.

In recent years, the introduction of the electroless hot-plating method has been considered in implementing such copper wiring technology. Electroless plating is a method of forming a metal film by obtaining electrons from a reducing agent added to a plating liquid without using electrolysis from the outside. The technique of forming a copper seed layer in a recess before the copper is buried in the recess, Forming a plated film made of CoWP (cobalt tungsten phosphorus), which is an adhesion layer between the barrier film and copper, before forming a barrier film (for example, a film of silicon nitride, silicon carbide, silicon carbide, etc.) on the copper wiring. It is applied to technology.

Regarding electroless plating, for example, a semiconductor wafer (hereinafter referred to as a wafer) in which a peripheral edge (circumferential edge) is held on a chuck is heated by a temperature adjusting plate from both upper and lower sides, and at a predetermined temperature, for example, at room temperature. A method of supplying an electroless plating solution heated at a set temperature up to a degree Celsius to the surface of a wafer via an upper plate is disclosed (Patent Document 1).

By the way, since the electroless plating solution contains a reducing agent which is a source of electrons, especially when heated and used, so-called precipitation in liquid, which precipitates metal in the liquid, easily occurs. When precipitation occurs in the liquid, the state of the electroless plating solution changes, so that the electroless plating process varies between wafers, for example, the film thickness of the plating film becomes uneven, and the precipitated particles become a factor of particle contamination. In addition, there is a danger of clogging the pipes of the electroless plating apparatus. Patent Document 1 does not focus on the instability of such an electroless plating solution.

SUMMARY OF THE INVENTION The present invention has been made under such circumstances, and an object thereof is to provide an electroless plating apparatus capable of stabilizing a state of an electroless plating solution and allowing stable plating treatment on the surface of a substrate. For example, in carrying out an electroless plating process in the manufacturing process of a semiconductor device, the electroless plating solution contains a reducing agent which is a source of electrons, and especially when heated and used, metal precipitates out of the liquid and becomes unstable. This avoids this, stabilizes the state of the electroless plating solution, and performs stable plating on the surface of the substrate.

According to one aspect of the invention, the substrate holding portion for holding the substrate in the transverse posture,

A first chemical liquid supply passage and a second chemical liquid supply passage through which the first chemical liquid and the second chemical liquid are mixed with each other to form an electroless plating solution, respectively;

These first chemical liquid supply passages and the second chemical liquid supply passages join at their upstream ends, and the supply passages of the electroless plating solution having discharge ports formed at their downstream ends;

Supply passage temperature adjusting means for adjusting the temperature of the electroless plating liquid in the supply passage of the electroless plating liquid,

Chemical liquid opening and closing means provided in the vicinity of a confluence point in each of the first chemical liquid supply passage and the second chemical liquid supply passage;

Plating liquid opening and closing means provided in the vicinity of the discharge port in the supply path of the electroless plating liquid;

Control means for controlling the opening and closing means for the chemical liquid and the opening and closing means for the plating liquid so as to supply the electroless plating solution which has filled the supply path of the electroless plating liquid to the surface of the next substrate while the electroless plating is being performed on the substrate. Equipped,

An electroless plating apparatus is provided in which the volume in the supply path between the chemical liquid opening and closing means and the plating liquid opening and closing means corresponds to the discharge amount required for electroless plating of one substrate. The first chemical opening and closing means and the second chemical opening and closing means may serve as one chemical opening and closing means. This electroless plating apparatus is provided with a means for adjusting the flow volume of each of the 1st chemical liquid and the 2nd chemical liquid, for example.

The present invention aims to mix the first chemical liquid and the second chemical liquid as soon as possible before the electroless plating treatment and to suppress the amount of the chemical liquid used as much as possible. The process proceeds to the processing of the next substrate after the treatment of one substrate is started. Both chemical liquids are mixed during the process, and the mixed liquid (electroless plating solution) is based on the idea of running out in the processing of the next substrate. Therefore, the meaning that the opening and closing means for the chemical liquid is provided in the vicinity of the confluence point in each of the first chemical liquid supply passage and the second chemical liquid supply passage means that it is possible to approach the confluence point of the chemical liquid supply passage as far as possible in the structurally acceptable part of the part. Say composition. When the distance between the confluence point and each chemical opening / closing means is large, the liquid filled therebetween becomes a mixture of both chemicals by the diffusion of the chemical, but the mixing action occurs in a stopped state after the chemical opening / closing means is closed. Therefore, it is supplied on a board | substrate without being fully mixed, and plating uniformity will fall. In other words, even if the opening and closing means for each chemical liquid is slightly away from the confluence point due to the limitation of the structure of the part, the layout, and the like, if the plating nonuniformity due to insufficient mixing does not occur, the "near confluence point" do.

In addition, "the volume V1 in the supply path between the chemical opening / closing means and the plating liquid opening / closing means corresponds to the discharge amount V2 required for electroless plating one substrate" equally between V1 and V2. It means. V2 is, for example, the total amount of the liquid accumulated on the surface of the substrate to be electroless plated and the volume (volume of liquid) from the opening and closing means for the plating liquid to the discharge port. When the relationship between V1 and V2 is described, when V1 is larger than V2, when one discharge amount is set to V2, the plating liquid remains in the plating liquid supply path, and when one discharge amount is set to V1, more than necessary amount is discharged. , Chemical liquid is wasted. On the contrary, when V1 is smaller than V2, when one discharge amount is set to V2, the first chemical liquid and the second chemical liquid located in each of the chemical liquid supply paths are discharged without remaining in the plating liquid supply path, so that the plating liquid on the substrate is uniform. Deterioration For this reason, it is ideal that V1 and V2 are equivalent, but there may be cases where a difference occurs in the design. Also in this case, if the uniformity of the plating treatment is ensured and the design is to eliminate waste of the chemical solution as much as possible, V1 and V2 become "even".

According to one preferred embodiment of the present invention, an upper temperature controller which faces the surface of the substrate held in the substrate holding portion and is formed larger than the effective area of the substrate, and has the discharge opening formed on the lower surface thereof, And a moving mechanism relatively moved between the processing position for filling the electroless plating liquid between the surface of the substrate and the standby position away from the processing position. Here, the upper temperature control body, the inside thereof has a flow chamber of the temperature control fluid, the supply path temperature control means, the heat exchange between the temperature control fluid and the electroless electrolyte solution to adjust the temperature of the electroless solution An entirety of the supply path of the electroless plating solution is disposed in the flow chamber of the upper temperature control body so as to be provided. Further, the first chemical liquid supply passage and the second chemical liquid supply passage, in which the portion filled with the chemical liquid filled in the supply passage of the electroless liquid, are disposed in the flow chamber of the upper temperature control body. In this case, part or all of the supply passage of the electroless plating solution can be arranged in the upper temperature regulating body, so that part or all of the supply passage temperature regulating means is used by the upper temperature regulating body.

The upper temperature regulating body is configured such that the inside thereof is configured as a flow chamber of the temperature controlling fluid, and the entire supply path of the electroless plating liquid is disposed in the flow chamber for heat exchange between the electroless plating liquid and the temperature adjusting fluid. By this means, the supply passage temperature regulating means may be used.

In the present invention, the first chemical liquid supply passage and the second chemical liquid supply passage may be provided with means for adjusting the temperature of a portion filled with the chemical liquid used for one substrate through the chemical opening / closing means. In the case where the inside of the upper temperature controller is configured as a flow chamber for the temperature control fluid, the flow chamber may be used as a means for temperature-regulating the portion filled with the chemical liquid. As a specific example of the chemical liquid, the first chemical liquid is, for example, a liquid containing a metal salt of a plated metal, and the second chemical liquid is, for example, a liquid containing a reducing agent for supplying electrons.

In addition, the electroless plating apparatus of the present invention may be provided opposite the lower surface of the substrate, and may include a lower temperature controller having a substrate temperature adjusting means for adjusting the temperature of the substrate. Preferably, the substrate temperature adjusting means adjusts the temperature of the substrate by filling the temperature-regulated fluid in the lower temperature controller between the lower temperature controller and the substrate.

According to another aspect of the invention, in the electroless plating method using the electroless plating apparatus of the present invention, the first chemical liquid is a liquid containing a metal salt of the plating metal, the second chemical liquid is a reducing agent which is a source of electrons An electroless plating method is provided, which is a liquid containing.

According to still another aspect of the present invention, in the electroless plating method using the electroless plating apparatus of the present invention, simultaneously performing the opening and closing operations of the first chemical liquid opening and closing means, the second chemical liquid opening and closing means and the plating liquid opening and closing means An electroless plating method is provided.

According to another aspect of the present invention, in the electroless plating method using the electroless plating apparatus of the present invention, the electroless plating method is characterized in that the supply path temperature adjusting means and the upper temperature control body are adjusted to a plating treatment temperature. Plating methods are provided.

According to another aspect of the present invention, in the electroless plating method using the electroless plating apparatus of the present invention, means for adjusting the temperature provided in the supply path temperature control means, the first chemical liquid supply path and the second chemical liquid supply path It is provided with an electroless plating method characterized in that it is adjusted to the plating treatment temperature.

According to another aspect of the present invention, in the electroless plating method using the electroless plating apparatus of the present invention, the electroless plating method is characterized in that the supply path temperature adjusting means and the substrate temperature adjusting means are adjusted to a plating treatment temperature. Plating methods are provided.

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

1 is a diagram showing the overall configuration of an embodiment of an electroless plating apparatus of the present invention. 1, 11 is a wafer chuck forming a flat cylindrical substrate holding part with an upper opening, and an end portion 12 holding the circumferential portion of the wafer W as a substrate is formed at the periphery of the upper end of the wafer chuck 11. It is formed over. A cylindrical rotary shaft 13 is provided at the center of the wafer chuck 11, and the rotary shaft 13 is connected to a rotary drive unit, for example, a hollow motor 14. The hollow chuck 14 is configured such that the wafer chuck 11 is rotatable about a vertical axis in a state in which the wafer W is supported. The hollow motor 14 is fixed to the base 15, and the base 15 is attached to the inclination mechanism 16 so that it can be inclined.

On the outside of the wafer chuck 11, a cup 21 for receiving a liquid is provided so as to surround the wafer chuck 11, and the cup 21 can be raised and lowered relative to the base 15 by a lifting mechanism not shown. Consists of. The upper end of the side circumferential surface of the cup 21 is bent inward to repel the liquid shaken off when the wafer W is rotated. In addition, an opening 22 is formed in the bottom central portion of the cup 21, and the rotary shaft 13 penetrates through the opening 22, and the liquid overflowed from the wafer W in a portion near the periphery of the bottom surface. A drain discharge portion 23 for discharging the water as a drain is provided. In addition, even in the bottom surface off the center of the wafer chuck 11, a hole portion not visible in the drawing is formed, and the liquid overflowed into the wafer chuck 11 flows into the cup 21.

An upper temperature controller 3 is provided on the upper side of the wafer chuck 11 so as to face the surface of the wafer W held by the wafer chuck 11. The upper temperature control member 3 is made of a slightly larger size than the wafer W in a cylindrical shape with a flat outer appearance, and is provided with a processing position for supplying an electroless plating liquid to the wafer W by a lifting mechanism 30 which is a moving mechanism. It is comprised so that it can go up and down among the standby positions which were moved upward from this processing position. The upper temperature regulator 3 may be larger than the effective area of the wafer W (the integrated circuit formation area), but in recent years, since the integrated circuit is formed to be substantially close to the periphery of the wafer W, the upper temperature controller 3 is equal to or larger than the size of the wafer W. It is desirable to be large. In addition, a lower temperature controller 24 is disposed in the wafer chuck 11, and the lower temperature controller 24 faces the rear surface of the wafer W held by the wafer chuck 11 so as to face the rotating shaft 13. It is comprised so that it can go up and down by the lifting mechanism not shown through the support shaft 25 which penetrates inside. Although the upper temperature control body 3 and the lower temperature control body 24 are comprised by the plate which consists of ceramics, for example with the heater which consists of resistance heating bodies, for example, the plate through which a heat medium flows may be sufficient.

One end side of the pure water supply pipe 26, which is a supply path of temperature control water, for example, pure water (pure water), is inserted into the central portion of the lower surface of the lower temperature controller 24, and the pure water supply pipe 26 has a support shaft ( It is piped in 25, and the other end side thereof is connected to the pure water tank 29 via the valve 27 and the pump 28. Moreover, this pure water also has a role as a back side rinse liquid.

The elevating mechanism 30 of the upper temperature regulating body 3 and the elevating mechanism not shown of the lower temperature regulating body 24 are fixed to the base 15, and thus the upper temperature regulating body 3 is fixed by the inclination mechanism 16. ), The wafer W and the lower temperature controller 24 are inclined integrally. Although the purpose of inclining these is as mentioned later, when the process liquid, such as an electroless plating liquid, is filled between the upper temperature control body 3 and the wafer W, the bubble mixed in it is moved to the upper side, and it removes, but this Example In this case, since the bubble is hard to enter, it is not necessary to provide the inclination mechanism 16.

Next, the supply system of the electroless plating solution will be described with reference to FIG. 2. One end side of the supply path 41 of the electroless plating solution made of, for example, a pipe is disposed at the center of the upper temperature regulating member 3, and the lower end thereof is flush with the lower surface of the upper temperature regulating member 3. The discharge port 42 of the electroless plating liquid is formed. At the upper side of the upper temperature regulating body 3 in the electroless plating solution supply passage 41, a valve 43 corresponding to the plating liquid on / off valve for supplying and shutting off the liquid in the supply passage 41 is provided. The upstream side of the electroless plating liquid supply passage 41 branches into the first chemical liquid supply passage 5 and the second chemical liquid supply passage 6. That is, the first chemical liquid supply passage 5 and the second chemical liquid supply passage 6 join at the upstream end of the electroless plating solution supply passage 41. The electroless plating liquid supply passage 41 is surrounded by the supply passage temperature adjusting means 44 so that the electroless plating liquid in the supply pipe 41 is set to a temperature selected from a predetermined temperature, for example, from room temperature to 60 ° C. Consists of. In this example, the supply passage temperature adjusting means 44 is configured such that the heat medium, for example, pure water, flows through the heat medium supply path 46 and the heat medium discharge path 47 in the cylindrical case body 45. In the valve 43, a heater 48 constituting a part of the supply passage temperature adjusting means 44 is provided around the valve 43 to adjust the temperature of the electroless plating liquid in the valve 43.

The first chemical liquid supply passage 5 and the second chemical liquid supply passage 6 are supply passages through which the first chemical liquid and the second chemical liquid which are mixed with each other to form an electroless plating liquid flow through, respectively, at a confluence point (electroless plating liquid supply passage). In the vicinity of the upper end of 41, valves 51 and 61 serving as opening and closing means for the chemical liquid are provided. These valves 51 and 61 are arranged as close to the confluence point as possible within an allowable range in the layout of the component. The reason is that the chemical liquid is allowed to diffuse and mix as uniformly as possible during the stationary state waiting for the next wafer W to be processed.

The first chemical liquid supply passage 5 is provided with a chemical liquid supply source 52, a pump 53, and a flow rate adjusting unit 54 in this order from the upstream side, and the second chemical liquid supply passage 6 has a chemical liquid supply source (from the upstream side). 62), the pump 63 and the flow rate adjusting part 64 are provided in this order. The first chemical liquid comprises a metal salt containing a component forming an electroless plating film, a complexing agent for complexing the metal so that the metal ion does not precipitate as a hydroxide under strong alkalinity, and a pH adjuster for adjusting the pH of the liquid. It is included.

The metal salt consists of the first metal salt and the second metal salt containing the components of the alloy when the components of the film are alloys. Specific examples of the components of the first chemical liquid include, for example, cobalt sulfate, cobalt chloride, nickel sulfate, nickel chloride, and tungstic acid and ammonium tungstate as the first metal salt. As a complexing agent, citric acid, sodium citrate, sodium hydroxide and TMAH (tetramethylammonium hydroxide) can be selected as a pH adjuster, for example.

The second chemical liquid contains a reducing agent for catalytically reducing precipitation of metal ions and a pH adjusting agent for adjusting the pH of the liquid. As a reducing agent, DMAB (dimethylamine borane) etc. are mentioned, for example. The first and second chemicals are stored, for example, at room temperature and are maintained at pH 10. Incidentally, the components listed are one example, and these components may not necessarily be used.

These first chemical liquids and the second chemical liquids each have a predetermined mixing ratio by the flow adjusting portions 54 and 64, for example, the first chemical liquid: the second chemical liquid has a ratio of 9: 1, and one wafer. The flow rate is adjusted so that the discharge amount of the electroless plating liquid for processing W is, for example, 50 cc.

Here, the volume V1 in the electroless plating solution supply passage 41 between the valves 51 and 61 serving as the opening and closing means for the chemical liquid and the valve 43 serving as the opening and closing means for the plating liquid is used for electroless plating one wafer W. It is designed to correspond to the discharge amount V2 (50 cc in this example) required for the purpose. As for the relationship between V1 and V2, as described in detail in the section of the technical problem to be achieved by the invention, for example, the discharge amount V2 may be associated with the wafer W in a state where no liquid is present downstream of the valve 43. The amount of liquid passing through the valve 43 when the electroless plating liquid is filled between the upper temperature controller 3 (the amount of liquid required for processing one wafer W). In other words, it corresponds to the total amount of the volume between the wafer W and the upper temperature controller 3 and the volume from the valve 43 to the discharge port 42. In this case, since the electroless plating liquid from the valve 43 to the discharge port 42 is wasted, it is preferable that the valve 43 approach the discharge port 42 as much as possible, for example, the upper temperature regulator It is also possible to provide a valve of the type for opening and closing a flow path using a piezoelectric element in (3).

In the vicinity of the electroless plating solution supply passage 41 in the upper temperature regulator 3, a supply passage 71 of pure water, which is a cleaning liquid, is disposed, and the downstream end of the pure water supply passage 71 is an upper temperature controller ( It is formed as the discharge port 72 opened in the lower surface of 3), and the pure water tank 73 is provided in the upstream end. The downstream end of the pure water supply passage 71 may be opened between the valve 43 and the discharge port 42 in the electroless plating solution supply passage 41. Reference numeral 74 denotes a pump, and 75 denotes a valve for blocking supply of pure water in the pure water supply passage 71. In addition, the electroless plating apparatus is provided with, for example, a control unit 100 made of a computer, and the control unit 100 includes pumps 53, 63, 74, and valves 43, 51. And a sequence program for controlling the operations of (61), (75) and the like.

1, this electroless plating apparatus is equipped with the several nozzle which can move freely between the supply position of the fluid above the wafer W hold | maintained by the wafer chuck 11, and a standby position. In FIG. 1, two nozzles 17 and 18 are shown for convenience. For example, the nozzle 17 is for supplying the replacement plating solution to the surface of the wafer W before the electroless plating solution, and is connected to a supply source of the replacement plating solution through a pipe (not shown). The nozzle 18 is for supplying a drying gas, for example, an inert gas, and is connected to a supply source of drying gas through a pipe (not shown). These nozzles 17 and 18 are provided with, for example, a discharge port of a slit shape, for example, having a length greater than or equal to the radius of the wafer W. The nozzles 17 and 18 are free to lift and move freely in the lateral direction, for example, by turning, not shown. It is freely constructed.

Next, the operation of the above-described embodiment will be described. First, the upper temperature regulating body 3 is kept at the standby position, and the wafer chuck 11 is lowered, and the surface of the wafer W is adsorbed by the conveying means (not shown) and conveyed to the upper side of the wafer chuck 11. The wafer chuck 11 is raised to pass the wafer W of the conveying means to the wafer chuck 11 (state of FIG. 1). In addition, as shown in FIG. 3A, the surface of the wafer W is in a state in which copper wiring 302 is embedded in a recess of the interlayer insulating film 301, for example. Reference numeral 303 denotes a barrier film for preventing copper in the recess from diffusing into the insulating film 301.

Subsequently, as shown in FIG. 4A, for example, the nozzle 17 moves on the wafer W, the pretreatment liquid is supplied onto the wafer W while the wafer W is rotated through the wafer chuck 11, and the pretreatment liquid is purged. Form them. The pretreatment solution is, for example, a substitution plating solution for performing palladium substitution plating, and the substitution plating solution may be one obtained by dissolving a palladium salt made of palladium sulfate or palladium chloride in an acid solution such as sulfuric acid or hydrochloric acid. This substitution plating solution is temperature-controlled at a temperature selected within a range of, for example, from room temperature to 60 ° C, and is supplied to the surface of the wafer W. Thus, as shown in FIG. Copper having a redox potential lower than that of palladium is dissolved in by passing electrons to palladium, and a catalyst layer 304 made of palladium that receives the electrons is selectively deposited on the surface of the copper wiring 302. Although the catalyst layer 304 acts as a catalyst for the electroless plating treatment in a later step, some catalysts do not require a catalyst, and in this case, an organic acid solution is transferred from the nozzle 17 to the wafer W. In some cases, preprocessing may be performed by supplying. Thereafter, as shown in FIG. 4B, a cleaning liquid, for example, pure water, is supplied from the nozzle 18 while rotating the wafer W to remove the pretreatment liquid.

Thereafter, the nozzle 18 is retracted from the upper side of the wafer W, and the upper temperature controller 3 is lowered and set at a position where the distance between its lower surface and the surface of the wafer W becomes, for example, 0.1 mm to 2 mm. do. At this time, the lower temperature regulating body 24 is also raised to set at a position where the distance from the back surface of the wafer W is, for example, 0.1 mm to 2 mm. When the pure water, which is a temperature control liquid, is pumped by the pump 28, it passes through the pure water supply pipe 26, passes through the lower temperature control body 24, and is heated to a predetermined set temperature.

The heated pure water flows into the wafer chuck 11 while filling the gap between the lower temperature controller 24 and the back surface of the wafer W, and flows into the cup 21 through a hole not shown in the figure. In addition, since the upper surface of the lower temperature control body 24 is also maintained at the set temperature, the wafer W is heated from the rear surface side to maintain the plating process temperature. After heating the wafer W for a predetermined time, for example, 10 seconds, the pumps 53, 63 shown in Fig. 2 are driven, and the valves 43, 51, and 61 are opened simultaneously. After the set time has elapsed, the pumps 53, 63 are stopped, and the valves 43, 51, and 61 are closed at the same time. As described above, by simultaneously opening and closing the valve, the backflow of the chemical liquid can be prevented. This set time is the time required for all the liquids between the valves 43, 51, and 61 in the electroless plating solution supply passage 41 to be discharged. As shown in FIG. 5A, The electroless plating liquid in the electroless plating liquid supply passage 41 is supplied and filled at a flow rate of, for example, 30 to 100 ml / min between the wafer W and the upper temperature controller 3.

When the electroless plating solution is supplied to the wafer W one wafer before the wafer W, the first and second chemical solutions are respectively discharged from the first and second chemical supply passages 5 and 6. Joined via (51) and (61), flows into the electroless plating solution supply passage 41, and is mixed by diffusion until it is supplied to the wafer W to form an electroless plating solution, and the supply passage temperature adjusting means ( The temperature is controlled by 44) and becomes active. In addition, the upper temperature control body 3 is also heated to the same temperature as the set temperature of the electroless plating solution, for example. Thus, the wafer W is temperature-controlled from both front and back, so that the electroless plating process is performed. That is, palladium precipitated on the surface of the wafer W in the previous step acts as a catalyst to cause a reaction between the electroless plating solution and copper, and selectively phosphorus (P) on the surface of the copper wiring 302 as shown in FIG. 3C. For example, an electroless plated film 305 is formed, for example, NiP, CoWP, NiP, CoP, or the like, which is formed of an alloy containing a thin film.

The electroless plating solution in the region disposed between the valves 51, 61, and 43 in the electroless plating solution supply passage 41 was extruded by the discharge of the current electroless plating solution, but at the same time Through (51) and (61), respectively, the new first chemical liquid and the second chemical liquid are adjusted to the flow rate ratio of 9: 1 in the flow rate adjusting sections 54 and 64, as described above, to fill the region within the corresponding region. Inflow by (V1).

At this time, since pure water, which also serves as washing water, is supplied to the back side of the wafer W, so-called back rinsing is performed by the pure water, thereby preventing the electroless plating solution from returning to the back side of the wafer W. In addition, during processing, the wafer W may be rotated through the wafer chuck 11 to further increase in-plane temperature uniformity of the wafer W. FIG. In this step, the inclination mechanism 16 may be used to incline the wafer W, the upper temperature control body 3 and the lower temperature control body 24 so as to remove bubbles entering the gap from the electroless plating solution. This treatment is effective in the case where gas is generated by the reaction between the electroless plating solution and copper.

Next, the valve 75 of the pure water supply passage 71 shown in FIG. 2 is opened, and pure water is discharged from the discharge port 72 between the wafer W and the upper temperature regulator 3 as shown in FIG. 5B. It supplies and replaces the electroless plating liquid of the surface of the wafer W with pure water. Then, the upper temperature regulating body 3 is raised and shown in FIG. 6A using the nozzles (provided for convenience) 18 in the nozzle group represented by the nozzles 17 and 18. As described above, the post-cleaning liquid is supplied onto the rotating wafer W, and the surface of the wafer W is post-cleaned. At this time, pure water is supplied as a back rinse to the back side of the wafer W. As shown in FIG. Post-cleaning is performed to reduce the leakage current between lines, and as the post-cleaning solution, for example, an organic acid and a hydrofluoric acid-based aqueous solution are used. In addition, the supply of pure water which is performed after the electroless plating treatment may be performed by raising the upper temperature controller 3 and using the nozzle 18.

Subsequently, pure water as a cleaning liquid is supplied to the surface of the rotating wafer W from the nozzle of the nozzle group described above (provided with the convenience phase 18), and then discharge of the cleaning liquid is stopped, as shown in Fig. 6B. The wafer W is rotated at high speed and dried. At this time, a drying gas such as an inert gas may be blown out on the surface of the wafer W from the nozzles of the nozzle group described above to promote drying. In this way, after a series of processes are completed, the surface of the wafer W is adsorbed by a conveying means (not shown), and the wafer W is taken out from the wafer chuck 11.

According to the above-described embodiment, the valves 51 and 61 serving as opening and closing means for the chemical liquid are provided in the vicinity of the confluence point in each of the first chemical liquid supply passage 5 and the second chemical liquid supply passage 6. And a valve 43 serving as an opening and closing means for the plating liquid in the vicinity of the discharge port 42 in the electroless plating solution supply passage 41, and disposed between these valves 43, 51, and 61. The volume of the supply path 41 to be made corresponds to the discharge amount required for the plating treatment of one wafer W. Therefore, since both chemicals are mixed only until the plating process of the wafer W is started and the electroless plating process of the next wafer W of the wafer W is started, the time that both chemicals are mixed is short, It can be said that both chemicals are mixed just before the so-called electroless plating is performed. For this reason, it can be avoided that the electroless plating liquid is maintained in an unstable state, and the precipitation in the liquid can be prevented. As a result, an electroless plating process can be performed on the surface of the wafer W while the electroless plating solution is stable, and the film thickness and the film quality between the wafers W are improved. In addition, since there is no fear of particle precipitation, there is no occurrence of particle contamination or clogging of pipes.

In addition, since almost all of the electroless plating solution in the atmosphere is used for the electroless plating process on the wafer W, the consumption amount of the electroless plating solution can be suppressed, and the cost of the electroless plating solution is considerably high, thereby reducing the processing cost. Contributes to. In addition, when the valve is located in the first chemical liquid supply passage 5 and the second chemical liquid supply passage 6 away from the confluence point, the chemical liquids are not sufficiently mixed, but the valve 51 is located near the confluence point as in this example. By providing (61), the two liquids are sufficiently mixed, the concentration of the electroless plating liquid becomes uniform, and as a result, a process having high in-plane or inter-plane uniformity can be performed. If the first chemical liquid supply passage 5 and the second chemical liquid supply passage 6 are joined in a V-shape in the longitudinal direction, there is no liquid accumulation and there is no fear of bubbles.

Here, with respect to the chemical liquid supply passages 5 and 6, as shown in FIG. 7A, the first chemical liquid supply passage 6 is thinner than the first chemical liquid supply passage 5, and the first chemical member is vertically standing. The structure in which the second chemical liquid supply passage 6 is obliquely joined to the chemical liquid supply passage 5 may be formed, or as shown in FIG. 7B, the two chemical liquid supply passages 5 and 6 are joined in a V-shape. The three-way valve 40 is provided at the confluence point, and the two chemical solution supply passages 5 and 6 communicate with the electroless plating solution supply passage 41 at the same time, and at the same time the state is blocked. The three-way valve 40 may be configured to select a state.

As a means for adjusting the flow rates of the first chemical liquid and the second chemical liquid, a mixing ratio may be set by adjusting the discharge amount of each chemical liquid using a pump capable of controlling the discharge amount, for example, a bellows pump, without providing a flow rate adjusting unit. .

8 and 9 are diagrams showing main parts of other embodiments of the present invention. In this example, the upper temperature regulating member 3 has a cylindrical shape and is formed in a size slightly larger than that of the wafer W. The inside of the upper temperature regulating member 3 is a flow chamber 31 through which a temperature control fluid, for example, a heat medium such as pure water flows. Consists of. The heat medium supply pipe 32 is connected near the outer edge part of the upper surface of the upper temperature control body 3, and, for example, is a position symmetrical with the heat medium supply pipe 32 with respect to the center of the upper temperature control body 3. The heat medium discharge pipe 33 is connected.

In this flow chamber 31, the tubular first chemical liquid supply passage 5 and the second chemical liquid supply passage 6 are piped from the upper surface side, and each of the chemical liquid supply passages 5, 6 is, for example. It is formed in a spiral shape, and joins in the middle, and the lower end of the electroless plating solution supply passage 41, which is the conduit, is formed on the lower surface of the upper temperature regulating body 3 as the discharge port 42. In this example, the chemical liquid supply passages 5 and 6 and the electroless plating liquid supply passage 41 are described above except that they are disposed in the flow chamber 31 of the heat medium of the upper temperature control member 3. In the same manner as in the embodiment, the valves 51 and 61 are provided near the confluence points in the first chemical liquid supply passage 5 and the second chemical liquid supply passage 6, and at the same time, they are electroless. The valve 43 is provided in the vicinity of the discharge port 42 in the plating liquid supply passage 41. Moreover, the volume of the supply path 41 arrange | positioned between the valves 43, 51, and 61 is corresponded to the discharge amount required for the plating process of 1 sheet of the wafer W. Moreover, as shown in FIG. In such a configuration, the temperature change of the electroless plating liquid is smooth, and there is an advantage that the overheating is not performed even when the temperature of the electroless plating liquid is set to a high temperature.

Further, in the first chemical liquid supply passage 5 and the second chemical liquid supply passage 6, the chemical liquid used for one substrate is filled by passing through the valves 51 and 61, which are the opening and closing means for the chemical liquid. About the site | part, ie, the site | part in which the chemical | medical solution necessary for processing one sheet of the wafer W from the valve 51 and 61 in the 1st chemical liquid supply path 5 and the 2nd chemical liquid supply path 6 is filled, respectively, It is located in the flow chamber 31. In this case, since the chemical liquid is already heated to the processing temperature of the electroless plating solution, the time until the start of the electroless plating after mixing the first chemical liquid and the second chemical liquid can be shortened.

This point is related to the temperature of the electroless plating process, but for example, when the temperature of the electroless plating process is set to 60 ° C., the next wafer is supplied after supplying the electroless plating solution to the surface of one wafer W. If the time until the preparation of the electroless plating treatment for the surface of W is short, the electroless plating solution is heated up to the processing temperature in the electroless plating solution supply path 41 in the embodiment of FIG. You may need to add some waiting time. On the other hand, if the temperature of the first chemical liquid and the second chemical liquid is preheated (preheated) as in this example, the time for raising the temperature to the treatment temperature when the two chemicals are mixed is shortened, resulting in a high yield. Can be. Also in the embodiment of Fig. 1, the temperature adjusting means is provided in a structure for heating the temperature of the first chemical liquid and the second chemical liquid in advance, for example, the first chemical liquid supply passage 5 and the second chemical liquid supply passage 6, respectively. The structure may be provided.

The present invention is not limited to the above-described examples of the first chemical liquid and the second chemical liquid, and can be applied to the case where the chemical liquid is mixed in time and causes liquid precipitation or other defects.

According to the present invention, the opening and closing means for the chemical liquid is provided near the confluence point in each of the first chemical liquid supply passage and the second chemical liquid supply passage, and the opening and closing of the plating liquid near the discharge port in the supply passage of the electroless plating solution. A means is provided, and the volume of the supply path arrange | positioned by these opening / closing means is made to correspond to the discharge amount required for approximately one plating process. Therefore, since the plating treatment of the substrate is started and both chemicals are mixed only until the next electroless plating treatment of the next substrate of the substrate is started, in other words, the chemical liquids are mixed just before the electroless plating treatment is performed. Maintaining the plating liquid in an unstable state can be avoided as much as possible, for example, to prevent liquid precipitation. As a result, since an electroless plating solution in an equal state can always be supplied to the surface of the substrate, stable electroless plating can be performed, and the film thickness and film quality between the substrates are improved.

Claims (14)

A substrate holding part for holding the substrate in a horizontal posture; A first chemical liquid supply passage in which the first chemical liquid flows, A first chemical liquid supply source communicating with an upstream end of the first chemical liquid supply passage; A first chemical liquid opening and closing means installed to be connected to a downstream end of the first chemical liquid supply passage to control distribution of the first chemical liquid; A second chemical liquid supply passage through which the second chemical liquid flows, A second chemical liquid supply source communicating with an upstream end of the second chemical liquid supply passage; A second chemical liquid opening and closing means installed to be connected to a downstream end of the second chemical liquid supply passage to control the flow of the second chemical liquid; An upstream end communicates with a confluence point between the downstream end of the first chemical supply path and the downstream end of the second chemical supply path, and the electroless solution formed by mixing the first chemical solution and the second chemical solution flows to the substrate. Supply path of the electroless amount supplied to the upper surface, Supply passage temperature adjusting means for adjusting a plating liquid temperature in the supply passage of the electroless electrolyte; An opening and closing means for a plating liquid, which is connected to a downstream end, which is a discharge port of the supply path of the electroless electrolyte, to control the flow of the electroless electrolyte; And control means for controlling the opening and closing means for the first chemical liquid, the opening and closing means for the second chemical liquid, and the opening and closing means for the plating liquid, to supply the electroless electrolyte to the upper surface of the substrate, The volume in the supply passage of the electroless electrolytic solution surrounded by the first chemical opening / closing means, the second chemical opening / closing means and the plating liquid opening / closing means corresponds to the discharge amount required for electroless plating one substrate. Characterized Electroless plating equipment. The method of claim 1, An upper temperature controller facing the upper surface of the substrate held in the substrate holding portion and formed larger than the effective area of the substrate, and having a discharge port for supplying the electroless solution in the lower surface; And a moving mechanism for relatively moving the upper temperature regulating member between the upper temperature regulating member and the upper surface of the substrate and a processing position for filling the electroless liquid and a standby position away from the processing position. Characterized Electroless plating equipment. The method of claim 2, The upper temperature control body, the inside thereof has a flow chamber of the temperature control fluid, The supply path temperature adjusting means arranges the entire supply path of the electroless plating solution in the flow chamber of the upper temperature regulating body so that the temperature of the electroless plating solution is adjusted by heat exchange between the temperature control fluid and the electroless plating solution. Characterized by Electroless plating equipment. The method of claim 2, The upper temperature control body, the inside thereof has a flow chamber of the temperature control fluid, The first chemical liquid supply passage and the second chemical liquid supply passage, The first chemical liquid used for one substrate is filled at the upstream end of the first chemical opening / closing means and the second chemical liquid used for one substrate is filled at the upstream end of the second chemical liquid opening and closing means. Characterized in that the site is disposed in the flow chamber of the upper temperature regulator. Electroless plating equipment. The method of claim 1, The first chemical liquid supply passage and the second chemical liquid supply passage, The first chemical liquid used for one substrate is filled at the upstream end of the first chemical opening / closing means and the second chemical liquid used for one substrate is filled at the upstream end of the second chemical liquid opening and closing means. Characterized in that it comprises a means for temperature control of the site Electroless plating equipment. The method of claim 1, The first chemical opening and closing means and the second chemical opening and closing means, characterized in that also serves as a single chemical opening and closing means Electroless plating equipment. The method of claim 1, Means for adjusting the respective flow rates of the first chemical liquid and the second chemical liquid Electroless plating equipment. The method of claim 1, And a lower temperature controller disposed opposite the lower surface of the substrate and having a substrate temperature adjusting means for adjusting the temperature of the substrate. Electroless plating equipment. The method of claim 8, The substrate temperature adjusting means adjusts the temperature of the substrate by filling a temperature-regulated fluid in the lower temperature controller between the lower temperature controller and the substrate. Electroless plating equipment. In the electroless plating method using the electroless plating apparatus according to claim 1, The first chemical liquid is a liquid containing a metal salt of the plating metal, the second chemical liquid is a liquid containing a reducing agent which is a source of electrons Electroless plating method. In the electroless plating method using the electroless plating apparatus according to claim 1, Opening and closing the first chemical liquid opening and closing means, the second chemical liquid opening and closing means and the plating liquid opening and closing means simultaneously Electroless plating method. In the electroless plating method using the electroless plating apparatus according to claim 2, The supply path temperature control means and the upper temperature control body characterized in that for adjusting the plating treatment temperature Electroless plating method. In the electroless plating method using the electroless plating apparatus according to claim 5, Characterized in that for adjusting the supply path temperature control means and the temperature control means installed in the first chemical liquid supply path and the second chemical liquid supply path to the plating treatment temperature. Electroless plating method. In the electroless plating method using the electroless plating apparatus according to claim 8, The supply path temperature adjusting means and the substrate temperature adjusting means characterized in that for adjusting the plating treatment temperature Electroless plating method.

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