Film forming device

Abstract

To provide a film forming device capable of preventing a defective pattern resulting from crystallization of a metal ion sticking to the surface of a patterning mask by suppressing the metal ion present in a plating solution from crystallizing.SOLUTION: A film forming device 1 comprises an anode 11, an electrolyte membrane 13 disposed between the anode 11 and a substrate, i. e., a cathode, a mounting table 15 disposed to face the electrolyte membrane 13, for the substrate to be mounted thereon, a liquid storage chamber 14 comprising an opening 141 opening to the side of the mounting table 15 and closed by the electrolyte membrane 13 to house the anode 11 and a plating liquid S, a storage chamber moving unit 22 moving the liquid storage chamber 14 closer to or away from the mounting table 15, a patterning mask 12 disposed below the electrolyte membrane 13 and attached to the liquid storage chamber 14 together with the electrolyte membrane 13, and a cleaning container 17 detachably attached to the mounting table 15, for the patterning mask 12 to be immersed therein.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a film formation apparatus, and more particularly to a film formation apparatus suitable for solid phase electrodeposition. [Background technology]

[0002] The solid-phase electrodeposition method is a method in which a voltage is applied between the substrate, which is an anode and a cathode, while the substrate is pressurized with an electrolyte membrane in contact with a plating solution containing metal ions, and a metal coating derived from the metal ions contained in the electrolyte membrane is formed on the surface of the substrate. A known film-forming apparatus suitable for the solid-phase electrodeposition method includes a liquid storage chamber that contains an anode and a plating solution and has an opening on the substrate side that is blocked by the electrolyte membrane, a mounting table that is arranged opposite the liquid storage chamber and on which the substrate is placed, and a power supply unit that applies a voltage between the anode and the substrate.

[0003] Recently, a film forming apparatus has been developed that forms a wiring layer by forming a metal film in an area corresponding to a wiring pattern using a patterning mask. However, in a film forming apparatus using a patterning mask, if the metal film is left for a long time after it is formed, the metal ions in the plating solution attached to the patterning mask crystallize on the surface of the patterning mask, resulting in wiring pattern defects such as non-precipitation and pattern bleeding. For example, if the plating solution is a solution containing copper sulfate, if it is left for a long time after film formation, the plating solution attached to the surface of the patterning mask will be concentrated due to the evaporation of water. Then, when the solubility is exceeded, copper sulfate will crystallize on the surface of the patterning mask. The crystallized copper sulfate becomes a foreign matter, and the problem of metal non-precipitation occurs at that point. Furthermore, when the patterning mask is pressed against the substrate, the crystallized copper sulfate bites into the patterning mask, which causes the patterning mask to float, reducing the sealing property and leading to pattern bleeding.

[0004] In order to solve such problems, a method of cleaning a patterning mask using a water washing tank, as described in, for example, Patent Document 1 below, has been investigated. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-185122 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, there is a problem that it is difficult to apply the water washing tank described in Patent Document 1 to a film forming apparatus as is.

[0007] The present invention has been made to solve such technical problems, and aims to provide a film forming apparatus that can suppress crystallization of metal ions in a plating solution adhered to the surface of a patterning mask and prevent pattern defects caused by the crystallization of metal ions. [Means for solving the problem]

[0008] The film forming apparatus according to the present invention is characterized in comprising: an anode, an electrolyte membrane arranged between the anode and a substrate which is a cathode; a mounting stage arranged opposite the electrolyte membrane and on which the substrate is placed; a liquid storage chamber which stores the anode and a plating solution and has an opening facing the mounting stage which is blocked by the electrolyte membrane; a storage chamber movement unit which moves the liquid storage chamber closer to or away from the mounting stage; a patterning mask which is arranged below the electrolyte membrane and which is attached to the liquid storage chamber together with the electrolyte membrane; and a cleaning container which is arranged detachably with respect to the mounting stage and in which the patterning mask can be immersed.

[0009] In the film forming apparatus according to the present invention, the cleaning container is detachably arranged on the mounting table and is capable of immersing the patterning mask. For example, after the film is formed on the substrate, the cleaning container is arranged on the mounting surface and the patterning mask attached to the liquid storage chamber is immersed in the solution in the cleaning container to clean the plating solution adhering to the surface of the patterning mask. As a result, crystallization of metal ions in the plating solution adhering to the surface of the patterning mask can be suppressed, and pattern defects caused by crystallization of metal ions can be prevented. In addition, since the cleaning container is detachably arranged on the mounting table, the cleaning container can be removed from the mounting surface of the mounting table during the film formation on the substrate to prevent the film formation from being hindered. Effect of the Invention

[0010] According to the present invention, it is possible to suppress the crystallization of metal ions in a plating solution that has adhered to the surface of a patterning mask, and to prevent pattern defects caused by the crystallization of metal ions. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view showing a film forming apparatus according to an embodiment. [Diagram 2] FIG. 11 is a schematic cross-sectional view showing a state in which a patterning mask is immersed in a cleaning container. [Diagram 3] FIG. 11 is a schematic cross-sectional view showing a modified example of the cleaning container. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of a film forming apparatus according to the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted. In the following description, "upper" refers to the direction away from the mounting table arranged opposite the liquid storage chamber, and "lower" refers to the direction approaching the mounting table.

[0013] The substrate (not shown) described in this embodiment is a member for manufacturing a wiring board, and includes, for example, an insulating substrate and a metal seed layer formed on the surface of the insulating substrate. The wiring board includes the insulating substrate and a wiring layer having a predetermined wiring pattern provided on the surface of the insulating substrate. The wiring layer is composed of a metal seed layer and a metal layer further formed on the surface of the metal seed layer. This metal layer is made of a metal film formed using the film forming apparatus of this embodiment.

[0014] The insulating substrate is not particularly limited as long as it has insulating properties. For example, it is preferable to use a substrate made of glass epoxy resin, a substrate made of baked glass epoxy resin, a flexible film-like substrate made of polyimide resin or the like, or a substrate made of glass.

[0015] The metal seed layer is made of at least one metal selected from the group consisting of silver, copper, gold, nickel, palladium, and platinum.

[0016] 1 is a schematic cross-sectional view showing a film forming apparatus according to an embodiment. The film forming apparatus 1 of this embodiment is a plating apparatus that forms a metal layer by forming a metal film in an area corresponding to a wiring pattern using a solid-phase electrodeposition method. The film forming apparatus 1 includes a metal anode 11, an electrolyte membrane 13 disposed between the anode 11 and a substrate as a cathode, a liquid storage chamber 14 that contains the anode 11 and a plating solution S, a mounting table 15 disposed below the liquid storage chamber 14 and on which the substrate is placed, and a power supply unit 16 that applies a voltage between the anode 11 and the substrate.

[0017] The anode 11 has a plate, mesh, porous or metal ball shape, and is embedded in the top plate 142 of the liquid containing chamber 14 facing the electrolyte membrane 13 so as to be in contact with the plating solution S filled in the liquid containing chamber 14. The anode 11 is electrically connected to the positive electrode of the power source 16 via a conductor or the like. The anode 11 may be either a soluble anode made of the same material as the metal layer (e.g., copper), or an anode made of a material insoluble in the plating solution S (e.g., titanium).

[0018] The liquid containing chamber 14 is made of a material insoluble in the plating solution S, and is formed to have a space therein for containing the plating solution S. The liquid containing chamber 14 has an opening 141 that opens downward (i.e., toward the mounting table 15). The opening 141 is closed by the electrolyte membrane 13.

[0019] The liquid storage chamber 14 is provided with a supply port 14a through which the plating solution S is supplied and a discharge port 14b through which the plating solution S is discharged. The supply port 14a and the discharge port 14b are formed in a side wall portion 143 of the liquid storage chamber 14, and are connected to the tank 19 and the pump 20 via piping. The plating solution S discharged from the tank 19 by the pump 20 flows into the liquid storage chamber 14 from the supply port 14a, and is discharged from the discharge port 14b and returned to the tank 19. A pressure regulating valve 21 is provided downstream of the discharge port 14b, and the plating solution S in the liquid storage chamber 14 can be pressurized to a predetermined pressure by the pressure regulating valve 21 and the pump 20.

[0020] The electrolyte membrane 13 is a so-called solid electrolyte membrane, and is made of a porous membrane or a porous resin membrane having a certain degree of flexibility. The electrolyte membrane 13 is disposed below the liquid storage chamber 14 so as to face the anode 11, and closes the opening 141. The electrolyte membrane 13 is impregnated (contains) metal ions contained in the plating solution S by contacting the electrolyte membrane 13 with the plating solution S contained in the liquid storage chamber 14. When a voltage is applied to the electrolyte membrane 13 in close contact with the substrate, the electrolyte membrane 13 deposits metal derived from the metal ions on the surface of the substrate (more specifically, on the surface of the metal seed layer), thereby forming the metal layer.

[0021] Examples of materials for the electrolyte membrane 13 include fluorine-based resins such as Nafion (registered trademark) manufactured by DuPont, hydrocarbon-based resins, polyamic acid resins, and resins having an ion exchange function such as Selemion (CMV, CMD, CMF series) manufactured by Asahi Glass Co., Ltd. The thickness of the electrolyte membrane 13 is, for example, 5 to 200 μm.

[0022] In addition, a patterning mask 12 is disposed below the electrolyte membrane 13. The patterning mask 12 is a plating mask for forming a predetermined wiring pattern on the surface of the base material, and is in close contact with the lower surface of the electrolyte membrane 13. Although not shown, the electrolyte membrane 13 and the patterning mask 12 are detachably attached to the bottom of the liquid containing chamber 14 by members, jigs, or the like that support their peripheral portions.

[0023] The plating solution S is a solution containing the metal of the metal film to be formed (i.e., the metal of the metal layer) in an ion state, and examples of the metal include copper, nickel, silver, and tin. The plating solution S is an aqueous solution in which these metals are dissolved (ionized) with an acid such as nitric acid, phosphoric acid, succinic acid, sulfuric acid, or pyrophosphoric acid. For example, when the metal is nickel, the plating solution S can be an aqueous solution of nickel nitrate, nickel phosphate, nickel succinate, nickel sulfate, nickel pyrophosphate, or nickel sulfamate. When the metal is copper, the plating solution S can be an aqueous solution containing copper sulfate, copper pyrophosphate, or the like. In this embodiment, the plating solution S is an aqueous solution containing copper sulfate.

[0024] The mounting table 15 is made of a conductive material and is disposed below the liquid storage chamber 14 so that the substrate placed thereon faces the electrolyte membrane 13. The mounting table 15 is electrically connected to the negative electrode of the power supply unit 16. The upper surface of the mounting table 15 facing the liquid storage chamber 14 forms a mounting surface (not shown) on which the substrate is placed. When placed on the mounting surface, the metal seed layer of the substrate is electrically connected to the mounting table 15 via a conductive member (not shown).

[0025] The film forming apparatus 1 also includes a chamber moving unit 22 that is disposed above the liquid storage chamber 14 and moves the liquid storage chamber 14 closer to or farther from the mounting table 15. The chamber moving unit 22 is configured, for example, with a hydraulic or pneumatic cylinder, an electric actuator, a linear guide, and a motor. By driving the chamber moving unit 22, the liquid storage chamber 14 can be brought closer to the mounting table 15 so that the electrolyte membrane 13 attached below the liquid storage chamber 14 can come into contact with the substrate placed on the mounting surface. By driving the chamber moving unit 22, the liquid storage chamber 14 can be moved away from the mounting table 15 so that the electrolyte membrane 13 moves away from the substrate.

[0026] Furthermore, the film forming apparatus 1 of this embodiment is provided with a cleaning container 17 which is detachably disposed on the mounting table 15 and in which the patterning mask 12 can be immersed. The cleaning container 17 is a water tank which opens upward (i.e., toward the liquid storage chamber 14). The opening of the cleaning container 17 is formed slightly larger than the lower surface of the patterning mask 12 so that the patterning mask 12 attached to the bottom of the liquid storage chamber 14 can be smoothly immersed.

[0027] 1, the cleaning container 17 is, for example, equipped with wheels, and is guided by rails 24 that are suspended between a pair of bases 18, so that the cleaning container 17 can move between a cleaning position where it is placed on the mounting surface of the mounting table 15, and a retracted position where it is separated from the mounting surface. Position restriction members 23 that restrict the movement range of the mounting table 15 are provided on both ends of the rails 24. The cleaning container 17 is made of, for example, a resin material.

[0028] The immersion of patterning mask 12 in cleaning container 17 will be described below with reference to Fig. 2. In Fig. 2, in order to make it easier to understand the immersed state of patterning mask 12, the solution (here, pure water W) contained in cleaning container 17 is shown in grey. Pure water W is used to clean patterning mask 12, and preferably, pure water W having a conductivity of 3 μS / cm or less at room temperature is used.

[0029] The appropriate amount of pure water W to be contained in cleaning container 17 is an amount that does not overflow when patterning mask 12 is completely immersed, and is an amount that, when copper sulfate in patterning mask 12 dissolves in pure water W, is below the saturated solubility of copper sulfate.

[0030] Patterning mask 12 is cleaned by lowering liquid containing chamber 14 by driving containing chamber moving unit 22 and immersing patterning mask 12 in pure water W in cleaning container 17. At this time, it is necessary to leave a certain gap (for example, about 1 mm) so that the lower surface of patterning mask 12 does not touch the bottom surface of cleaning container 17. This is because, if the lower surface of patterning mask 12 touches the bottom surface of cleaning container 17, copper sulfate crystallized on the lower surface of patterning mask 12 may be pressed into patterning mask 12. Once copper sulfate is embedded, it is difficult to remove, and in some cases, patterning mask 12 may become unusable.

[0031] The patterning mask 12 is washed within 10 minutes after the film is formed, for example, when the next film is not formed after the film is formed on the base material. When the patterning mask 12 is immersed in the pure water W in the cleaning container 17, the liquid containing chamber 14 is moved up and down using the containing chamber moving part 22 to rock the patterning mask 12, thereby promoting dissolution of the crystallized copper sulfate. Furthermore, the temperature of the pure water W is set to room temperature to 40°C, which further promotes dissolution of the copper sulfate.

[0032] 2, in this embodiment, the electrolyte membrane 13 in close contact with the patterning mask 12 is also immersed in the pure water W in the cleaning container 17, but it is sufficient to immerse only the patterning mask 12 in the pure water W. However, by immersing the electrolyte membrane 13 in the pure water W together with the patterning mask 12, it is expected to have the effect of suppressing drying of the surface of the electrolyte membrane 13.

[0033] In the film forming apparatus 1 of the present embodiment, the cleaning container 17 is detachably arranged on the mounting table 15 and is capable of immersing the patterning mask 12. For example, after film formation, the cleaning container 17 is moved to a cleaning position (i.e., a position where the cleaning container 17 is arranged on the mounting surface of the mounting table 15) and the patterning mask 12 attached to the liquid storage chamber 14 is immersed in the pure water W in the cleaning container 17, thereby cleaning the plating solution S attached to the surface of the patterning mask 12. Therefore, crystallization of copper sulfate in the plating solution S attached to the surface of the patterning mask 12 can be suppressed, and pattern defects caused by copper sulfate crystals can be prevented. In addition, since the cleaning container 17 is detachably arranged on the mounting table 15, the cleaning container 17 can be removed from the mounting surface of the mounting table 15 and moved to a retreat position during film formation on the base material to prevent film formation from being hindered. As a result, even if the patterning mask 12 is left for a long time during repeated and continuous film formation, pattern defects do not occur and the quality of the film formation can be ensured.

[0034] [Examples and Comparative Examples] In order to verify the effects of the invention, the inventors of the present application performed the following evaluations using a film-forming apparatus 1 (Example) equipped with a cleaning container 17 and a film-forming apparatus (Comparative Example) not equipped with a cleaning container. In both the Example and Comparative Example, the first film-forming was performed under conditions of a temperature of 40° C. and a film-forming rate of 1.5 μm / min, and then the substrate was replaced and a second film-forming was performed under the same conditions.

[0035] In the embodiment, after the first film formation and before replacing the substrate, the patterning mask 12 was immersed in the pure water W in the cleaning container 17 and washed. Then, the second film formation was carried out. The state of the pattern on the substrate on which the second film was formed was checked. As a result, there was no bleeding of the pattern.

[0036] On the other hand, in the comparative example, after the first film formation and after replacing the substrate, the patterning mask 12 was left for 60 minutes, and then the second film formation was performed. The state of the pattern on the substrate on which the second film was formed was confirmed. As a result, copper sulfate crystals were confirmed on the surface of the patterning mask 12, and the bleeding of the pattern was also confirmed.

[0037] The above results show that the film forming apparatus 1 of this embodiment can suppress the crystallization of metal ions (copper sulfate) in the plating solution that adhere to the surface of the patterning mask, thereby preventing pattern defects caused by the crystallization of metal ions.

[0038] [Variations] Various modifications of the cleaning container 17 according to this embodiment are possible.

[0039] For example, in the modified example shown in FIG. 3(a), a sheet 25 having a certain thickness is laid on the bottom surface of the cleaning container 17A to prevent the patterning mask 12 from touching the bottom surface of the cleaning container 17A. The sheet 25 is made of a material that is not easily corroded by the plating solution S and is softer than the material of the patterning mask 12. In addition, the sheet 25 preferably has a saw-like cross section so as not to hinder cleaning of the lower surface of the patterning mask 12 even if the sheet 25 comes into contact with the lower surface of the patterning mask 12. Furthermore, by making the cross section of the sheet 25 saw-like, it is possible to suppress the crystallized copper sulfate from biting into the patterning mask 12 even when the patterning mask 12 is pressed.

[0040] 3(b), a step 171 is provided on the periphery of the bottom of the cleaning container 17B. The height of the step 171 is, for example, about 1 mm from the bottom surface of the cleaning container 17B. This step 171 may be formed integrally with the cleaning container 17B using the same material, or may be formed separately from the cleaning container 17B and fixed to the cleaning container 17B by adhesion or the like. Furthermore, in order not to interfere with the formation of the wiring pattern, the step 171 is preferably provided in a location where there is no wiring pattern.

[0041] By providing step portion 171 in this manner, when patterning mask 12 is immersed in pure water W in cleaning container 17B, the immersion depth of patterning mask 12 can be regulated by its lower surface coming into contact with the upper surface of step portion 171, so that a constant gap can be easily secured between the lower surface of patterning mask 12 and the bottom surface of cleaning container 17B.

[0042] 3(c), an ultrasonic generator 26 is provided. That is, in this modification, instead of rocking the liquid containing chamber 14 up and down, the ultrasonic generator 26 is inserted into the pure water W, and the copper sulfate formed on the surface of the patterning mask 12 is washed by applying vibrations to the pure water W. In this case, the metallic ultrasonic generator 26 is placed in a cleaning container 17C and immersed in the pure water W to prevent dissolution of the metal ions (copper sulfate).

[0043] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made without departing from the spirit of the present invention as described in the claims. [Explanation of symbols]

[0044] 1: film forming device, 11: anode, 12: patterning mask, 13: electrolyte membrane, 14: liquid storage chamber, 14a: supply port, 14b: discharge port, 15: mounting table, 16: power supply unit, 17, 17A, 17B, 17C: cleaning container, 18: base, 19: tank, 20: pump, 21: pressure regulating valve, 22: storage chamber moving unit, 23: position control member, 24: rail, 25: sheet, 26: ultrasonic generator, 141: opening, 142: top plate portion, 143: side wall portion, 171: step portion

Claims

[Claim 1] An anode; an electrolyte membrane disposed between the anode and a cathode substrate; a mounting table disposed opposite the electrolyte membrane and on which the substrate is placed; a liquid containing chamber having an opening on the mounting table side and closed by the electrolyte membrane, the liquid containing chamber containing the anode and a plating solution; a container chamber moving unit that moves the liquid container chamber toward or away from the placement table; a patterning mask disposed below the electrolyte membrane and attached to the liquid containing chamber together with the electrolyte membrane; a cleaning container that is detachably disposed on the mounting table and in which the patterning mask can be immersed; A film forming apparatus comprising:

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