JP2022171371A - Deposition method for metallic film - Google Patents

Abstract

To provide a deposition method for a metallic film that can prevent a plating solution from excluding from a site not contacting to a body to be coated in a porous film.SOLUTION: A porous film 50 is pinched by a placing table 16 in which an accommodation recess 16a that accommodates a body to be coated W is formed so that a surface to coated F of the body to be coated W is exposed, and a clipping member 12 in which a liquid holding hole 13 by which plating solution L is held is formed at a location facing a surface to be coated F of the body to be coated W placed on the placing table 16, so that the surface to be coated F contacts the porous film 50. By compressing the plating solution L holed in the liquid holding hole 13, the plating solution L is impregnated into the porous film 50. After stopping the compression of the plating solution L, a metallic film is deposited on to the surface to be coated F with the plating solution L impregnated into the porous film 50.SELECTED DRAWING: Figure 1A

Description

The present invention relates to a film forming method for forming a metal film on a film forming surface of a film forming object.

As a technique of this kind, for example, Patent Document 1 discloses an anode, a porous film provided between the anode and a film-forming object, a porous film provided so as to be in contact with the film-forming object, and a and a power supply unit for applying a voltage between the anode and the film-forming body, and the porous membrane is composed of a polyolefin chain that does not have an ion-exchange functional group. A film forming apparatus is disclosed.

Using this film-forming apparatus, a plating solution is stored in the liquid storage chamber, and a voltage is applied between the anode and the film-forming body while the porous film and the cathode are in contact with each other. A metal coating can be deposited on the deposition region.

JP 2020-97764 A

However, in the film forming apparatus disclosed in Patent Document 1, when a porous film is used, the metal film is formed while the plating solution in the liquid storage chamber is pressurized. There is a possibility that the plating solution will seep out to the film portion.

The present invention has been made in view of these points, and an object of the present invention is to prevent the plating solution from seeping out even from the portions of the porous film that are not in contact with the substrate. The object of the present invention is to provide a method for forming a metal film that can suppress the amount of heat generated.

In view of the above-described problems, the method for forming a metal film according to the present invention provides a method for forming a metal film by pressing a porous film impregnated with a plating solution containing metal ions against a film-forming object, so that the surface of the film-forming object Among them, a method for forming a metal film comprising forming a metal film made of a metal derived from the metal ions on a surface to be formed that is in contact with the plating solution, the method comprising: A mounting table having a concave portion for housing the film-forming object so that the surface is exposed; a step of sandwiching the porous film with a sandwiching member having a liquid holding hole in which the plating solution is held so that the film-forming surface is in contact with the porous film; and a step of pressurizing the plating solution to impregnate the porous film with the plating solution; and a step of forming the metal film.

According to the present invention, in the step of sandwiching the porous film, the porous film is sandwiched between the mounting table accommodating the film-forming object and the holding member so that the film-forming surface is in contact with the porous film. As a result, the portion of the porous film that is not in contact with the surface to be formed is in contact with the surface of the mounting table and functions like a sealing material. It is possible to prevent the liquid from seeping out.

FIG. 4 is a schematic cross-sectional view for explaining a sandwiching step in the method for forming a metal film according to the first embodiment of the present invention; 1B is a schematic cross-sectional view for explaining a pressurizing step and a film forming step in a method for forming a metal film in the film forming apparatus shown in FIG. 1A; FIG. 1B is a schematic cross-sectional view for explaining a film forming process in the film forming apparatus for forming a metal film in the film forming apparatus shown in FIG. 1A. FIG. FIG. 1B is a cross-sectional view of a main part of a metal film deposition apparatus according to a modification of FIG. 1A; 2B is a schematic cross-sectional view for explaining a pressurizing step in the film forming apparatus for forming a metal film in the film forming apparatus shown in FIG. 2A. FIG. FIG. 1B is a schematic cross-sectional view for explaining a film forming apparatus that implements a film forming method that is a comparison of FIG. 1A. 3B is a schematic cross-sectional view for explaining a film forming method using the film forming apparatus shown in FIG. 3A; FIG. FIG. 2B is a schematic cross-sectional view for explaining a film forming apparatus that performs a film forming method for comparison with FIG. 2A. 4B is a schematic cross-sectional view for explaining a film forming method using the film forming apparatus shown in FIG. 4A; FIG.

A method for forming a metal film according to this embodiment will be described below. First, with reference to FIGS. 1A to 4B, a film forming apparatus used in the method for forming a metal film according to the first embodiment will be described.

1. 1. About Film Forming Apparatus As shown in FIG. 1, the film forming apparatus 1 according to the present embodiment presses a porous film 50 impregnated with a plating solution L containing metal ions against an object W to be film-formed. A metal film forming apparatus for forming a metal film made of a metal derived from the metal ions on a film forming surface F in contact with a plating solution L among the surfaces of the film forming object W.

As shown in FIG. 1A, the film forming apparatus 1 includes a mounting table 16 on which the film formation target W is mounted. , a recess 16a for accommodating the object W to be deposited is formed. A biasing member 28 such as a spring is arranged in the housing recess 16 a , and the biasing member 28 biases the film-forming body W toward the porous film 50 .

In this embodiment, the urging member 28 is set so that the object W to be film-formed is compressed and deformed so that it becomes substantially flush with the surface of the mounting table 16 (until it becomes the same surface) during film-forming. Therefore, the height of the object to be film-formed W, the spring constant of the urging member 28, etc. are adjusted so that the depth of the housing recess 16a matches the sum of the height of the object to be film-formed W and the compressively deformed urging member 28. is set.

The film forming apparatus 1 includes an apparatus main body 10. The apparatus main body 10 has a porous film 50 attached at a position facing a mounting table 16, and performs plating so that the porous film 50 seals the plating solution L. A liquid containing chamber 11 for containing the liquid L is formed. The mounting table 16 can be raised and lowered with respect to the apparatus main body 10 . The lifting and lowering of the mounting table 16 can be realized by a generally known device such as a linear motion device such as a linear guide.

Here, the plating solution L is stored in the liquid storage chamber 11 of the apparatus main body 10. For example, when forming a metal film on the object W to be deposited by electroless plating, It contains an electroless plating solution. Furthermore, when forming a metal film by electroplating, an anode (not shown) is arranged in the liquid storage chamber 11 at a position facing the object W to be film-formed. A power supply (not shown) is connected to the anode and the film-forming object W (cathode) with the film-forming object W as a cathode, and a voltage is applied between them during film-forming.

Furthermore, in the present embodiment, the housing 18 may be arranged so as to surround the mounting table 16, and the inside of the housing 18 is set to a negative pressure by sucking the air inside the housing 18 during film formation. A suction pump 30 may be connected. Thereby, the porous film 50 can be formed on the object W to be film-formed. The liquid storage chamber 11 is provided with a pressure pump 19 that pressurizes the plating solution L stored in the liquid storage chamber 11 .

The porous film 50 is a porous film in which fine pores through which the plating solution permeates are formed in the film thickness direction. have. The pores of the porous structure are very small, and the average pore diameter is, for example, 0.1 μm or more and 100 μm or less. By applying pressure, the solid electrolyte membrane can be impregnated with the electroless plating solution. When electroplating is performed, the porous membrane 50 is a solid electrolyte membrane through which metal ions permeate. , Selemion (CMV, CMD, CMF series) manufactured by Asahi Glass Co., Ltd., and other resins having an ion exchange function, but are not particularly limited to these. The film thickness of the porous membrane 50 is preferably 10 μm or more and 200 μm or less, more preferably 20 μm or more and 160 μm or less.

Metal ions contained in the plating solution L are, for example, metal ions such as copper ions, nickel ions, silver ions, or gold ions. In the case of an electroless plating solution, the electroless plating solution is preferably a so-called substitution type electroless plating solution. The electroless plating solution contains, for example, a metal compound and a complexing agent, and may contain additives as necessary. Additives include, for example, pH buffers, stabilizers, and the like. When the plating solution is an electrolytic plating solution, it is preferably an electrolytic solution in which the metal that forms the metal film is dissolved in the form of ions with sulfuric acid, nitric acid, or the like.

In this embodiment, as shown in FIG. 1B, the film formation surface F of the film formation object W is a surface having conductivity so as to serve as a cathode, and grooves R are formed thereon. In the case of electroless plating, the film-forming surface F may be coated with a catalyst such as palladium.

In this embodiment, a holding member 12 is further provided. The holding member 12 is formed with a liquid holding hole 13 in which the plating liquid L in the liquid storage chamber 11 is held at a position facing the film formation surface F of the film formation target W placed on the mounting table 16 . there is

In this embodiment, the holding member 12 is arranged closer to the liquid storage chamber 11 than the porous membrane 50 so as to be in contact with the porous membrane 50 . The plating solution L in the solution storage chamber 11 passes toward the porous film 50, and the solution holding hole 13 has an opening having a size corresponding to the film formation surface F on the porous film 50 side. The plating solution L contacts the porous film 50 through this opening.

By the way, in the film forming method using the comparative film forming apparatus 9 shown in FIG. A biasing member such as a spring is not provided in the accommodation recess 16a. In the state shown in FIG. 3A, when a metal film is formed on the film formation surface F of the film formation object W, a gap is formed between the mounting table 16 and the porous film 50 as shown in FIG. 3B. Therefore, the exuded plating solution enters into these gaps. As a result, a metal film can be formed also on the surface of the concave groove R of the object W to be film-formed by the bleeding of the plating solution L. However, in this case, even if a metal film can be formed on the surface of the groove R, a large amount of the plating solution L seeps out onto the mounting table 16, and the plating solution L cannot be wiped off. Occur.

Therefore, in the film forming method of the present embodiment, the following sandwiching step, impregnation step, and film forming step are performed. First, in the sandwiching step, as shown in FIG. 1A, a mounting table 16 having an accommodating concave portion 16a for accommodating the film-forming object W so that the film-forming surface F of the film-forming object W is exposed; The holding member 12 having the liquid holding hole 13 holding the plating solution L at a position facing the film formation surface F of the film formation object W placed on the mounting table 16 , and the porous film 50 . The porous film 50 is sandwiched so that the film-forming surfaces F are in contact with each other. At this time, the biasing member 28 is compressed and deformed, so that the film-forming surface F comes into contact with the plating solution L through the porous film 50, and the surface of the mounting table 16 is sandwiched through the porous film 50. contact member 12;

As shown in FIG. 1B , in the impregnation step, the pressure pump 19 is driven to pressurize the plating solution L in the solution storage chamber 11 , thereby pressurizing the plating solution L held in the solution holding holes 13 . As a result, the porous film 50 is impregnated with the plating solution L in the solution holding holes 13 .

Here, the portion of the porous film 50 that is not in contact with the film formation surface F is in contact with the surface of the mounting table 16 and functions like a sealing material. Even if the porous film is pressed, it is possible to prevent the plating solution from seeping out from the porous film. As a result, in the impregnation process, the liquid pressure of the plating solution L that has passed through the porous film 50 causes the biasing member 28 to be further compressed and deformed, thereby pushing down the object W to be film-formed. As a result, the grooves R formed in the film formation surface F of the film formation object W are also filled with the plating solution.

Furthermore, as shown in FIG. 1C, in the film formation process, the pressurization of the plating solution L by the pressure pump 19 is stopped, and the plating solution L impregnated in the porous film 50 is applied to the film formation surface F to form a metal film. to form a film. In this manner, according to the present embodiment, the plating solution L can be prevented from leaking onto the mounting table 16, so that the work of wiping the plating solution L off the mounting table 16 can be reduced.

Furthermore, as shown in FIG. 4A, in the film forming method using the film forming apparatus 9 as a comparison, when the heights of the film forming objects W (WA, WB) are different during film formation, the height of the object W (WA, WB) is The film-forming body WA protrudes from the surface of the mounting table 16 . Therefore, when a metal film is to be formed on the film-forming bodies WA and WB, when the porous film 50 is pressed against the film-forming bodies WA and WB, the height of the film-forming bodies WA and WB is higher than that of the film-forming bodies WB, which is short. Excessive stress acts on the portion of the porous film 50 in contact with the film formation surface F of the film formation object WA having a high thickness. As a result, as shown in FIG. 4B, there is a risk that the portion of the porous membrane 50 on which the excessive force is applied may be damaged.

However, in the present embodiment, even if the deposition targets WA and WB having different heights have different protruding amounts L1 and L2 from the mounting table 16 as shown in FIG. As shown, the urging member 28 may be set so as to compressively deform the object W to be film-formed until it becomes substantially flush with the surface of the mounting table 16 (until it becomes the same surface) during film-forming. As a result, the metal film can be formed on the film formation surfaces F of the film formation objects WA and WB while suppressing damage to the porous film 50 .

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 designs can be made without departing from the spirit of the invention described in the claims. Changes can be made.

1: film forming apparatus, 10: apparatus main body, 11: liquid storage chamber, 12: sandwiching member, 13: liquid holding hole, 16: mounting table, F: film formation surface, L: plating solution, W: film formation target body

Claims (1)

By pressing a porous film impregnated with a plating solution containing metal ions against a film-forming object, the metal ion A method for forming a metal film comprising a metal derived from
a mounting table having an accommodation recess for accommodating the film formation target so that the film formation surface of the film formation target is exposed; and the film formation target mounted on the mounting table. A step of sandwiching the porous film between a sandwiching member having a solution holding hole in which the plating solution is held at a position facing the film-forming surface so that the film-forming surface is in contact with the porous film. When,
a step of pressurizing the plating solution held in the solution holding holes to impregnate the porous membrane with the plating solution;
A step of stopping pressurization of the plating solution and forming the metal film on the film-forming surface with the plating solution impregnated in the porous film;
A method for forming a metal film containing at least

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