Inspection method for polymer electrolyte membrane

Abstract

To provide an inspection method for a polymer electrolyte membrane that can determine whether the polymer electrolyte membrane has been boiled under boiling conditions suitable for forming a metallic film.SOLUTION: An inspection method comprises: preparing a polymer electrolyte membrane 13; boiling the polymer electrolyte membrane 13; attaching the boiled polymer electrolyte membrane 13 to an apparatus body 10; pressurizing the polymer electrolyte membrane 13 with a plating solution L for a predetermined time while the polymer electrolyte membrane 13 is in contact with a base material B; and depressurizing the pressurized plating solution L. The method further comprises measuring an amount of the plating solution that seeps from the polymer electrolyte membrane 13 to the base material B and determining whether a metallic film F can be formed using the polymer electrolyte membrane 13 based on the amount of seepage.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for inspecting an electrolyte membrane used in a film-forming apparatus for forming a metal film on a substrate.

Background Art

[0002] As this type of technology, for example, Patent Document 1 proposes a film-forming apparatus for forming a metal film on a substrate. The film-forming apparatus includes an electrolyte membrane, and forms a metal film on the substrate by electrolytic plating in a state where the electrolyte membrane is in contact with the substrate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, before attaching the electrolyte membrane used in the film-forming apparatus to the apparatus main body of the film-forming apparatus, it may be boiled with a boiling liquid such as pure water. As a result, the electrolyte membrane swells due to the boiling liquid, and metal ions in the plating solution can pass through when electrolytic plating is performed.

[0005] However, since the swelling state of the electrolyte membrane varies depending on the boiling temperature, there is a possibility that the amount of the plating solution oozing out from the electrolyte membrane to the substrate during film formation may differ. Thereby, it is assumed that the characteristics of the formed metal film are affected. In particular, it is difficult to specify the swelling state of the electrolyte membrane from the appearance, and it is difficult to grasp whether the electrolyte membrane has been boiled under appropriate boiling conditions from the appearance of the electrolyte membrane.

[0006] The present invention has been made in view of such points, and an object thereof is to provide a method for inspecting an electrolyte membrane capable of inspecting whether the electrolyte membrane has been boiled under boiling conditions suitable for forming a metal film.

Means for Solving the Problem

[0007] In view of the above problems, the method for inspecting an electrolyte membrane according to the present invention is a method for inspecting an electrolyte membrane used in a film-forming apparatus for forming a metal film on a substrate. The electrolyte membrane is attached to the apparatus main body of the film-forming apparatus and is used when forming the metal film on the substrate by electrolytic plating while being in contact with the substrate. The inspection method includes: preparing the electrolyte membrane; boiling the electrolyte membrane; attaching the boiled electrolyte membrane to the apparatus main body; pressurizing the electrolyte membrane with a plating solution for a predetermined time while the electrolyte membrane is in contact with the substrate, and then depressurizing the pressurized plating solution; measuring the amount of the plating solution that oozes out from the electrolyte membrane into the substrate; and determining whether it is possible to form the metal film using the electrolyte membrane based on the amount of oozing.

Advantages of the Invention

[0008] According to the present invention, it is possible to inspect whether the electrolyte membrane has been boiled under boiling conditions suitable for forming a metal film.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0010] The inspection method of the electrolyte membrane will be described below with reference to FIGS. 1 and 2. The inspection method according to the present embodiment is an inspection method of the electrolyte membrane 13 used in the film forming apparatus 1 for forming the metal film F on the base material B as shown in FIGS. 2(a) and (b). The electrolyte membrane 13 is attached to the apparatus main body 10 of the film forming apparatus 1 and is used when forming the metal film F on the base material B by electrolytic plating while being in contact with the surface Ba of the base material B.

[0011] The film forming apparatus 1 includes an anode 11, an electrolyte membrane 13, and a power source 14 that applies a voltage between the anode 11 and the base material B. The film forming apparatus 1 further includes a container 15 that houses the anode 11 and the plating solution L, and a mounting table 40 on which the base material B is placed. The film forming apparatus 1 includes a linear actuator 70 that raises and lowers the container 15. The linear actuator 70 raises and lowers the container 15 by linearly moving a rod 72 so that the electrolyte membrane 13 and the base material B can be separated from and contacted with each other. The linear actuator 70 has a rod 72 that linearly moves with respect to the main body 71, and the container 15 is fixed to the tip of the rod 72. The apparatus main body 10 of the film forming apparatus 1 as referred to in the present invention is composed of the container 15, the anode 11, and the linear actuator 70.

[0012] The base material B functions as a cathode. The base material B may be made of a metal material such as aluminum or copper, for example. The anode 11 is electrically connected to the positive electrode of the power source 14. The negative electrode of the power source 14 is electrically connected to the base material B via the mounting table 40. The plating solution L is a solution that contains the metal of the metal film to be formed in an ionic state. Examples of the metal include copper, nickel, gold, or silver.

[0013] The electrolyte membrane 13 is a membrane that can be impregnated (contain) metal ions together with the plating solution L by contacting with the plating solution L. The electrolyte membrane 13 is a flexible membrane. When a voltage is applied by the power source 14, the material of the electrolyte membrane 13 is not particularly limited as long as the metal ions in the plating solution L can move to the substrate B side. Examples of the material of the electrolyte membrane 13 include resins having an ion exchange function such as fluorine-based resins such as Nafion (registered trademark) manufactured by DuPont.

[0014] The container 15 has a storage space 15a for storing the plating solution L. The anode 11 is disposed in the storage space 15a of the container 15. An opening 15d is formed on the side of the substrate B in the storage space 15a. By covering the opening 15d of the container 15 with the electrolyte membrane 13, in a state where the plating solution L is stored, the plating solution L in the storage space 15a is sealed by the electrolyte membrane 13.

[0015] The container 15 has a supply port 15b for supplying the plating solution L to the storage space 15a and a discharge port 15c for discharging the plating solution L from the storage space 15a. The supply port 15b and the discharge port 15c are formed with the storage space 15a therebetween. The supply port 15b is fluidly connected to the supply pipe 51. The discharge port 15c is fluidly connected to the discharge pipe 52.

[0016] The film forming apparatus 1 further includes a tank 58, a supply pipe 51, a discharge pipe 52, and a circulation pump 59. The tank 58 stores the plating solution L. The supply pipe 51 connects the tank 58 and the container 15, and a circulation pump 59 is provided in the supply pipe 51. The discharge pipe 52 connects the tank 58 and the container 15, and a pressure regulating valve 54 is provided in the discharge pipe 52. The pressure regulating valve 54 adjusts the pressure (liquid pressure) of the plating solution L in the storage space 15a to a predetermined pressure.

[0017] In this embodiment, by driving the circulation pump 59, the plating solution L is sucked from the tank 58 into the supply pipe 51 and pumped from the supply port 15b into the accommodation space 15a. The plating solution L in the accommodation space 15a is returned to the tank 58 via the discharge port 15c. Thereby, the circulation path 50 is formed.

[0018] As shown in FIG. 1, in this inspection method, first, in step S1, the electrolyte membrane 13 to be attached to the apparatus main body 10 (specifically, the container 15) of the film forming apparatus 1 is prepared, and the electrolyte membrane 13 is boiled with, for example, pure water. Thereby, the electrolyte membrane 13 swells and can permeate metal ions derived from the plating solution L during electrolytic plating.

[0019] Next, in step S2, the boiled electrolyte membrane 13 is attached to the container of the apparatus main body 10 as shown in FIG. 2(a). Next, in step S3, the plating solution L is supplied to the accommodation space 15a of the container 15. At this time, the plating solution L may be supplied in a state where the inspection base material B is accommodated in the accommodation recess 41 of the mounting table 40.

[0020] Next, in step S4, the state of the electrolyte membrane 13 such as breakage (tear, hole) is inspected. Specifically, in this inspection, by image analysis using a camera, the plating solution L leaking from the electrolyte membrane 13 may be confirmed. For example, when the plating solution L leaks out to the inspection base material B, the surface of the base material B changes color, so this discoloration may be confirmed, or the leakage of the plating solution L may be observed by water supply using water-sensitive paper and measurement of pH. Here, when the plating solution L is leaking, it is determined that the electrolyte membrane 13 is damaged.

[0021] In step S5, if it is determined that the electrolyte membrane 13 is damaged, the process returns to step S2, where the electrolyte membrane 13 is removed and another boiled electrolyte membrane 13 is attached to the apparatus main body 10. On the other hand, if the electrolyte membrane 13 is not damaged, the process proceeds to step S6. As shown in Fig. 2(b), with the electrolyte membrane 13 in contact with the substrate B, the electrolyte membrane 13 is pressurized with the plating solution L for a predetermined time (specifically, pressurized for the film formation time at the liquid pressure during film formation), and then the pressurized plating solution is depressurized. Due to this pressurization, the plating solution L accommodated in the accommodation space 15a oozes out to the surface Ba of the substrate B through the electrolyte membrane. When a mask is used during film formation, a mask is placed between the electrolyte membrane 13 and the substrate B, and the air between them is degassed (evacuated).

[0022] In step S7, the amount of the plating solution L that oozes out from the electrolyte membrane 13 to the substrate B is measured. Specifically, one measuring instrument such as a weighing scale, a pressure element (piezo element), or a load cell is installed on the back surface of the inspection substrate B or on the mounting table 40 that contacts this back surface, and the amount of the plating solution that oozes out (weight) is measured. Note that as the measuring instrument, one that is not damaged by the liquid pressure of the above-described plating solution is selected.

[0023] Next, based on the amount of oozing, it is determined whether the formation of the metal film F using the electrolyte membrane 13 is possible. Specifically, in step S8, if the amount of oozing is equal to or more than a predetermined value, it is determined that the electrolyte membrane 13 has swelled sufficiently due to boiling, so the metal film F can be formed, and the process proceeds to step S9. On the other hand, in step S8, if the amount of oozing is less than the predetermined value, it is determined that the boiling of the electrolyte membrane 13 is not sufficient and the metal film F cannot be stably formed. In step S9, the substrate B for film formation is installed on the mounting table 40, and the process proceeds to step S10, where the metal film F is formed on the substrate B for film formation (see Fig. 2(b)). In this way, by measuring the amount of the plating solution L that oozes out, it is possible to determine whether the electrolyte membrane 13 has been boiled under boiling conditions suitable for forming the metal film F.

[0024] The following confirmation tests were carried out. Specifically, using electrolyte membranes prepared under four conditions: (1) without boiling, (2) boiling at 70°C for 1 hour, (2) boiling at 80°C for 1 hour, and (3) boiling at 90°C for 1 hour, a metal film (wiring using a mask) was formed on the substrate. Film formation temperature: 40°C, film formation rate: 1.5 m / min, plating solution: a mixed solution of 1.0 mol / L copper sulfate + 0.2 mol / L sulfuric acid, liquid pressure (pressuring force): 0.6 Pa. Film formation was carried out on the surface of a 2.5 cm × 2.5 cm copper substrate using a patterning mask with a wiring pattern. The results are shown in Table 1 below.

[0025]

Table 1

[0026] Under the conditions of (1) and (2), the amount of seepage of the plating solution was small, the boiling of the electrolyte membrane was not sufficient, and it is considered that there were defects in the wiring part (metal film). On the other hand, under the conditions of (3) and (4), the amount of seepage of the plating solution was sufficient, the boiling of the electrolyte membrane was sufficient, and it is considered that there were no defects in the wiring part (metal film).

Explanation of Symbols

[0027] 1: Film forming apparatus, 10: Apparatus main body, 13: Electrolyte membrane, B: Substrate, F: Metal film, L: Plating solution

Claims

【Claim 1】 An inspection method for an electrolyte membrane used in a film-forming apparatus for forming a metal film on a substrate, comprising: The electrolyte membrane is attached to the apparatus main body of the film-forming apparatus and is used for forming the metal film on the substrate by electrolytic plating while being in contact with the substrate. The inspection method includes: preparing the electrolyte membrane and boiling the electrolyte membrane; attaching the boiled electrolyte membrane to the apparatus main body; pressurizing the electrolyte membrane with a plating solution for a predetermined time while the electrolyte membrane is in contact with the substrate, and then depressurizing the pressurized plating solution; measuring the amount of the plating solution that oozes out from the electrolyte membrane into the substrate; and determining whether it is possible to form the metal film using the electrolyte membrane based on the amount of oozing. An inspection method for an electrolyte membrane, characterized by including the above steps.

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