Resin Sheet Surface Treatment Method and Resin Sheet Surface Treatment Apparatus

Abstract

The present invention provides a method for surface treatment of a resin sheet, which can generate functional groups on the bonding surface of the resin sheet without roughening the surface of the bonding surface, and can improve the adhesion of the film to the bonding surface in the film forming process. In the method for surface treatment of a resin sheet according to the present invention, before the film forming process of bonding a film to the surface of the resin sheet (3), a surface treatment process is performed on the bonding surface of the resin sheet (3) to which the film is to be bonded. An inert gas (10) is introduced into the vacuum chamber (1) provided with the electrode (2), the resin sheet (3) is set to the ground potential, and a negative potential is applied to the electrode (2) by a high-frequency power supply (6) that periodically applies a negative potential.

Description

Technical Field

[0001] The present invention relates to a method for surface treatment of a resin sheet and a resin sheet surface treatment apparatus. In the method for surface treatment of a resin sheet, before a film-forming step of bonding a film to the surface of the resin sheet, a surface treatment step is performed on the bonding surface of the resin sheet to which the film is to be bonded. In the resin sheet surface treatment apparatus, an electrode is disposed in a vacuum chamber, an inert gas is introduced into the vacuum chamber, and the bonding surface of the resin sheet is surface-treated. Background Art

[0002] Patent Document 1 discloses that: before bonding, a gas introduced is ionized into plasma (or ions) by a plasma (or ion) generation unit, accelerated at a voltage of 1000 to 500,000 V, and irradiated onto a resin sheet on a metal roll maintained at a ground potential. Thus, in Patent Document 1,

[0003] By the instantaneous activation state obtained by the short-time and immediately preceding treatment with high-energy plasma (or ions), the adhesion strength of a film subsequently formed on the resin sheet can be significantly improved without causing deterioration of the resin sheet.

[0004] Patent Document 2 discloses that before forming a copper film on the surface of a resin layer, the surface of the resin layer is treated with nitrogen plasma, whereby while maintaining the smoothness of the surface of the resin layer, the surface treatment for improving the adhesion is performed.

[0005] In addition, Patent Documents 3 to 5 also disclose techniques for surface-treating a resin film using ionized nitrogen.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-71985

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2004-162098

[0010] Patent Document 3: Japanese Patent Application Laid-Open No. 2005-199544

[0011] Patent Document 4: Japanese Patent Application Laid-Open No. 2004-31370

[0012] Patent Document 5: Japanese Patent Application Laid-Open No. 2005-54259 Summary of the Invention

[0013] Problems to be Solved by the Invention

[0014] However, in Patent Document 1, since high-energy plasma (or ions) is irradiated onto the resin sheet, the surface roughness of the resin sheet increases.

[0015] In addition, in Patent Document 2, a substrate with a resin layer laminated thereon is also provided on the electrode. Since a negative potential is applied to the electrode, the plasmaized nitrogen ions are irradiated onto the resin layer. Therefore, similar to Patent Document 1, the surface roughness of the resin layer increases.

[0016] In addition, in Patent Documents 3 to 5, the ionized nitrogen gas is also irradiated onto the surface of the resin film.

[0017] Figure 7 An existing device for irradiating the ionized nitrogen gas onto the surface of the resin film is shown.

[0018] Figure 7 It is a structural diagram showing an existing resin sheet surface treatment device.

[0019] In the existing resin sheet surface treatment device, a plate-shaped electrode 2 is arranged in a vacuum chamber 1, an inert gas 10 is introduced into the vacuum chamber 1, and the bonding surface of the resin sheet 3 is surface-treated.

[0020] The resin sheet 3 moves at a specified speed through a roller 4. The roller 4 is connected to a high-frequency power supply (Rf power supply) 6 via a matching box 5. The high-frequency power supply 6 periodically applies a negative potential to the roller 4. The cable connecting the matching box 5 and the roller 4 is electrically insulated from the chamber forming the vacuum chamber 1 through an insulating member 7.

[0021] The plate-shaped electrode 2 is connected to a ground electrode. Therefore, the plate-shaped electrode 2 becomes a ground potential (0V).

[0022] According to this existing resin sheet surface treatment device, when a negative potential is applied, the plasmaized inert gas 10 moves toward the bonding surface of the resin sheet 3 with a high kinetic energy E 2 and thus damages the surface of the bonding surface of the resin sheet 3, making the surface of the bonding surface of the resin sheet 3 rough.

[0023] Therefore, an object of the present invention is to provide a resin sheet surface treatment method that can generate functional groups on the bonding surface without making the surface of the bonding surface of the resin sheet rough and can improve the adhesion of the thin film to the bonding surface in the film-forming process.

[0024] Technical solutions for solving the problem

[0025] The present invention provides a method for surface treatment of a resin sheet. Before the film-forming step of bonding a film to the surface of the resin sheet (3), a surface treatment step is performed on the bonding surface of the resin sheet (3) to which the film is to be bonded. It is characterized in that an inert gas (10) is introduced into a vacuum chamber (1) equipped with an electrode (2), the resin sheet (3) is set to a ground potential, and a negative potential is applied to the electrode (2) by a high-frequency power supply (6) that periodically applies a negative potential.

[0026] The resin sheet surface treatment method of the present invention according to claim 2, based on claim 1, is characterized in that a plate-shaped electrode (2) is used as the electrode (2), and the plate-shaped electrode (2) is made of a material that is difficult to etch.

[0027] The resin sheet surface treatment method of the present invention according to claim 3, based on claim 1 or 2, is characterized in that the inside of the vacuum chamber (1) is set to 0.1 Pa or more and 10 Pa or less.

[0028] The resin sheet surface treatment method of the present invention according to claim 4, based on any one of claims 1 to 3, is characterized in that the resin sheet (3) is a polyimide sheet, and the film is a copper film.

[0029] The resin sheet surface treatment method of the present invention according to claim 5, based on claim 4, is characterized in that through the above surface treatment step, 32×10 －3 % / Area or more of N-C=O bonding groups are generated on the bonding surface.

[0030] The resin sheet surface treatment method of the present invention according to claim 6, based on claim 5, is characterized in that through the above surface treatment step, the above N-C=O bonding groups and C-O groups are generated on the bonding surface, and the amount thereof is 64×10 －3 % / Area or more.

[0031] The resin sheet surface treatment method of the present invention according to claim 7, based on any one of claims 1 to 3, is characterized in that the resin sheet (3) is a polytetrafluoroethylene sheet, and the film is a copper film.

[0032] The resin sheet surface treatment method of the present invention according to claim 8, based on any one of claims 1 to 7, is characterized in that the inert gas 10 is N 2 , and H 2 O and the above N 2 are introduced into the vacuum chamber (1) together.

[0033] The present invention according to claim 9 provides a surface treatment apparatus for a resin sheet, in which an electrode (2) is disposed in a vacuum chamber (1), an inert gas (10) is introduced into the vacuum chamber (1), and the bonding surface of the resin sheet (3) is surface-treated. It is characterized in that the resin sheet (3) is set to a ground potential, and a negative potential is applied to the electrode (2) by a high-frequency power supply (6) that periodically applies a negative potential.

[0034] The resin sheet surface treatment apparatus of the present invention according to claim 10, based on claim 9, is characterized in that a plate-shaped electrode (2) is used as the electrode (2), and the plate-shaped electrode (2) is made of a material that is difficult to etch.

[0035] Advantages of the Invention

[0036] According to the resin sheet surface treatment method of the present invention, when a negative potential is applied, the plasmaized inert gas moves toward the electrode with high kinetic energy, and when a negative potential is not applied, the plasmaized inert gas acts on the bonding surface of the resin sheet with low kinetic energy. Therefore, functional groups can be generated on the bonding surface without roughening the surface of the bonding surface of the resin sheet, and the adhesion of the film to the bonding surface in the film-forming process can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural diagram of a resin sheet surface treatment apparatus showing an embodiment of the present invention.

[0038] Figure 2 It is a diagram showing the surface treatment result when a polyimide (PI) sheet is used as the resin sheet.

[0039] Figure 3 It is a diagram showing the evaluation result of film formation when a polyimide sheet is used as the resin sheet and the plasma treatment amount Q [kW / Fs] is changed.

[0040] Figure 4 It is a diagram showing the evaluation result of film formation when a polyimide sheet is used as the resin sheet, the plasma treatment amount Q [kW / Fs] is kept constant, and the introduced gas is changed.

[0041] Figure 5 It is a diagram showing the evaluation result of film formation when a polytetrafluoroethylene (PTFE) sheet is used as the resin sheet, the plasma treatment amount Q [kW / Fs] is kept constant, and the introduced gas is changed.

[0042] Figure 6 It is a photograph of the bonding surface of the resin sheet.

[0043] Figure 7 It is a structural diagram of a conventional resin sheet surface treatment apparatus.

[0044] Symbol Explanation

[0045] 1 Vacuum chamber, 2 Electrodes (plate electrodes), 3 Resin sheet, 4 Rollers, 5 Matching box, 6 High-frequency power supply (Rf power supply), 7 Insulating components, 10 Inert gas Detailed Implementation Modes

[0046] In the resin sheet surface treatment method of the first embodiment of the present invention, an inert gas is introduced into a vacuum chamber equipped with electrodes, the resin sheet is set to the ground potential, and a negative potential is applied to the electrodes by a high-frequency power supply that periodically gives a negative potential. According to this embodiment, when the negative potential is applied, the plasma inert gas moves towards the electrodes with high kinetic energy, and when the negative potential is not applied, the plasma inert gas acts on the bonding surface of the resin sheet with low kinetic energy. Therefore, functional groups can be generated on the bonding surface without roughening the surface of the bonding surface of the resin sheet, and the adhesion of the thin film to the bonding surface in the film-forming process can be improved.

[0047] Based on the resin sheet surface treatment method of the first embodiment of the present invention, the second embodiment of the present invention uses a plate electrode as the electrode and sets the plate electrode as a material that is difficult to etch. According to this embodiment, by setting the plate electrode as a material that is difficult to etch, the influence of the substances flying out from the electrodes on the bonding surface of the resin sheet can be prevented.

[0048] Based on the resin sheet surface treatment method of the first or second embodiment of the present invention, the third embodiment of the present invention sets the inside of the vacuum chamber to be 0.1 Pa or more and 10 Pa or less. According to this embodiment, by setting the vacuum degree to be 10 Pa or less, it is easy to adjust the kinetic energy of the inert gas.

[0049] Based on the resin sheet surface treatment methods of the first to third embodiments of the present invention, the fourth embodiment of the present invention sets the resin sheet as a polyimide sheet and sets the thin film as a copper thin film. According to this embodiment, while maintaining the smoothness of the surface roughness of the polyimide sheet, the copper thin film can be firmly adhered, and a copper thin film with smoothness can be formed. Therefore, the thin film surface resistance value of the copper thin film can be reduced, and the power loss of the copper thin film at high frequencies can be reduced. Furthermore, in the case of pattern etching of the resin sheet formed with the copper thin film, since the etched end face is smooth, a fine pattern can be formed, and the pattern accuracy can be improved.

[0050] Based on the resin sheet surface treatment method according to the fourth embodiment, the fifth embodiment of the present invention generates 32×10 on the bonding surface through the surface treatment process －3An N-C=O bonding group of 64×10

[0051] In the sixth embodiment of the present invention, based on the resin sheet surface treatment method of the fifth embodiment, through a surface treatment process, an N-C=O bonding group and a C-O group are generated on the bonding surface, and the amount thereof is 64×10 －3 % / Area or more. According to this embodiment, the adhesion force of the copper thin film can be improved, and this adhesion force can reach the level of cohesive peeling when the vapor deposition film formed on the resin sheet is peeled off from the resin sheet.

[0052] In the seventh embodiment of the present invention, based on the resin sheet surface treatment method of any one of the first to third embodiments, the resin sheet is a polytetrafluoroethylene sheet, and the thin film is a copper thin film. According to this embodiment, while maintaining the smoothness of the surface roughness of the polytetrafluoroethylene sheet, the copper thin film can be firmly adhered, and a copper thin film with smoothness can be formed. Therefore, the thin film surface resistance value of the copper thin film can be reduced, and the power loss of the copper thin film at high frequencies can be reduced. Furthermore, when patterning etching is performed on the resin sheet formed with the copper thin film, since the etched end face is smooth, a fine pattern can be formed, and the pattern accuracy can be improved.

[0053] In the eighth embodiment of the present invention, based on the resin sheet surface treatment method of any one of the first to seventh embodiments, the inert gas is N 2 , and H 2 O and N 2 are introduced into the vacuum chamber together. According to this embodiment, the smoothness of the surface roughness of the resin sheet can be maintained, and the thin film can be firmly adhered.

[0054] The resin sheet surface treatment device of the ninth embodiment of the present invention is a device that sets the resin sheet to a ground potential and applies a negative potential to the electrode through a high-frequency power supply that periodically gives a negative potential. According to this embodiment, when the negative potential is applied, the plasmaized inert gas moves toward the electrode with high kinetic energy, and when the negative potential is not applied, the plasmaized inert gas acts on the bonding surface of the resin sheet with low kinetic energy. Therefore, functional groups can be generated on the bonding surface without damaging the surface of the bonding surface of the resin sheet, and the adhesion force of the thin film to the bonding surface in the film formation process can be improved.

[0055] Based on the resin sheet surface treatment device of the ninth embodiment, the tenth embodiment of the present invention uses a plate-shaped electrode as the electrode and makes the plate-shaped electrode a material that is difficult to etch. According to this embodiment, by making the plate-shaped electrode a material that is difficult to etch, it is possible to prevent the influence of the substances flying out from the electrode on the bonding surface of the resin sheet.

[0056] [Examples]

[0057] Hereinafter, the resin sheet surface treatment device of the embodiment of the present invention will be described.

[0058] Figure 1 It is a structural diagram showing the resin sheet surface treatment device of this embodiment.

[0059] In the resin sheet surface treatment device of this embodiment, an electrode 2 is arranged in a vacuum chamber 1, an inert gas 10 is introduced into the vacuum chamber 1, and the bonding surface of the resin sheet 3 is surface-treated.

[0060] The surface treatment process for the bonding surface of the resin sheet 3 to which the thin film is to be bonded is carried out before the film-forming process of bonding the thin film to the surface of the resin sheet 3.

[0061] The resin sheet 3 moves at a specified speed through a roller 4. The roller 4 is connected to a ground electrode. Therefore, the resin sheet 3 becomes a ground potential (0 V) via the roller 4.

[0062] The electrode 2 is connected to a high-frequency power supply (Rf power supply) 6 via a matching box 5.

[0063] The high-frequency power supply 6 periodically applies a negative potential to the electrode 2. For example, the high-frequency power supply 6 applies between -160 V and 0 V to the electrode 2. The applied output of the high-frequency power supply 6 is 3 kW to 10 kW.

[0064] In addition, the cable connecting the matching box 5 and the electrode 2 is electrically insulated from the chamber forming the vacuum chamber 1 through an insulating member 7.

[0065] According to the resin sheet surface treatment device of this embodiment, when a negative potential is applied, the plasmaized inert gas 10 moves toward the electrode 2 with a high kinetic energy E 2 When the negative potential is not applied, the plasmaized inert gas 10 acts on the bonding surface of the resin sheet 3 with a low kinetic energy E 1 Therefore, it is possible to generate functional groups on the bonding surface without damaging the surface of the bonding surface of the resin sheet 3, and the adhesion of the thin film to the bonding surface in the film-forming process can be improved.

[0066] The electrode 2 preferably uses a plate-shaped electrode 2, and the plate-shaped electrode 2 is made of a material difficult to etch. By making the plate-shaped electrode 2 a material difficult to etch, the influence of the substances flying out from the electrode 2 on the bonding surface can be prevented. For example, tungsten, zirconium, molybdenum, or tantalum can be used as the material difficult to etch. In addition, since electrons are captured by using a magnetron electrode as the electrode 2, the temperature rise of the resin sheet 3 can be prevented.

[0067] The inside of the vacuum chamber 1 is preferably 10 Pa or less. If the degree of vacuum is set to 10 Pa or less, the kinetic energy of the inert gas 10 is easily adjusted.

[0068] Figure 2 It shows the surface treatment results when using a polyimide (PI) sheet as the resin sheet, and is the analysis results of the plasma treatment amount Q [kW / Fs] and X-ray photoelectron spectroscopy (XPS).

[0069] The applied output of the high-frequency power supply 6 is set to 3 kW, and the inside of the vacuum chamber 1 is set to 1.0 Pa. The inert gas 10 is set to N 2 and H 2 O and N 2 are introduced into the vacuum chamber 1 together.

[0070] Fs is the moving speed of the resin sheet 3. The treatment amount Q [kW / Fs] per unit speed is set to 0.45 [kW / Fs] in Example 1, 0.65 [kW / Fs] in Example 2, 0.75 [kW / Fs] in Example 3, and 1.50 [kW / Fs] in Example 4. In Comparative Example 1, the surface treatment of the present invention was not performed.

[0071] After the surface treatment was performed on each example, a film was formed by sputtering, and then a copper thin film with a thickness of 25 μm was formed by wet electrolytic plating. F 90 [N / 2mm] is the force when the copper thin film is stretched in the direction of 90 degrees with respect to the bonding surface of the resin sheet 3, and is the tensile force [N] per width of 2 mm, indicating the adhesion force of the copper thin film to the resin sheet 3. In addition, if F 90 [N / 2mm] exceeds 2 [N / 2mm], the agglomeration peeling of the vapor deposition film formed on the resin sheet 3 from the resin sheet 3 starts to occur.

[0072] The N-C=O bonding group was 14.8×10 －3 % / Area in Comparative Example 1. In contrast, 32×10 －3 % / Area or more was generated in Examples 1 to 4. The C-O group decreased in Examples 1 to 4 compared with Comparative Example 1, but the total of the N-C=O bonding group and the C-O group was less than 55×10 －3% / Area. In contrast, in Examples 1 to 4, 64×10 －3 % / Area or more is generated.

[0073] In addition, in Comparative Example 1, F 90 [N / 2mm] is approximately zero. In contrast, in Examples 1 to 4, F 90 [N / 2mm] is 1.5 [N / 2mm] or more, showing an adhesive strength of about 2 [N / 2mm] at which agglomeration peeling occurs, where the vapor deposition film formed on the resin sheet 3 peels off from the resin sheet 3.

[0074] Figure 3 These are the evaluation results of film formation when the polyimide sheet is used as the resin sheet and the plasma treatment amount Q [kW / Fs] is changed.

[0075] The applied output of the high-frequency power supply 6 is set to 3 kW, and the inside of the vacuum chamber 1 is set to 1.0 Pa.

[0076] In Examples 5 to 7, the inert gas 10 is set to N 2 , and H 2 O and N 2 are introduced into the vacuum chamber 1 together.

[0077] Fs is the moving speed of the resin sheet 3. The treatment amount Q per unit speed is set to 0.5 [kW / Fs] in Example 5, 1.0 [kW / Fs] in Example 6, and 1.5 [kW / Fs] in Example 7.

[0078] In Examples 5 to 7, after surface treatment, a film is formed by sputtering, and then a copper thin film with a thickness of 25 μm is formed by wet electrolytic plating. R 0 is the surface resistance [Ω / □] of the Cu thin film with a thickness of 4.5 μm formed by sputtering, and F 90 [N / 2mm] is the force when the copper foil film is stretched in a direction perpendicular to the bonding surface with the resin sheet 3, and is the tensile force [N] per 2 mm width.

[0079] As shown in Examples 5 to 7, even when the treatment amount Q is changed, the value of the Cu thin film surface resistance [Ω / □] remains the same as that of Comparative Example 1 without surface treatment. Therefore, it can be seen that in the resin sheet surface treatment method of the present invention, the bonding surface of the resin sheet 3 is not roughened.

[0080] In addition, in Examples 5 to 7, F 90 [N / 2mm] shows an adhesive strength of about 2 [N / 2mm] at which agglomeration peeling occurs, where the vapor deposition film formed on the resin sheet 3 peels off from the resin sheet 3.

[0081] Figure 4 Using a polyimide sheet as the resin sheet, the plasma treatment amount Q [kW / Fs] was set to be constant, and the evaluation results of film formation when introducing gas were changed.

[0082] The applied output of the high-frequency power supply 6 was set to 3 kW, and the inside of the vacuum chamber 1 was set to 1.0 Pa.

[0083] In Example 7, the inert gas 10 was set to N 2 , and H 2 O and N 2 were introduced into the vacuum chamber 1 together.

[0084] In Example 8, the inert gas 10 was set to N 2 , and N 2 was introduced into the vacuum chamber 1.

[0085] In Example 9, the inert gas 10 was set to Ar, and H 2 O and Ar were introduced into the vacuum chamber 1 together.

[0086] In Example 10, the inert gas 10 was set to Ar, and Ar was introduced into the vacuum chamber 1.

[0087] Fs is the moving speed of the resin sheet 3, and the treatment amount Q per unit speed was set to 1.5 [kW / Fs] in all of Examples 7 to 10.

[0088] After surface treatment was performed on each example, a film was formed by sputtering, and then a copper thin film with a thickness of 25 μm was formed by wet electrolytic plating. F 90 [N / 2mm] is the force when the copper foil film is stretched in a direction perpendicular to the bonding surface with the resin sheet 3, and is the tensile force [N] per 2 mm width.

[0089] In Examples 7 to 10, F 90 [N / 2mm] showed an adhesive strength of 2 [N / 2mm] or more at which agglomeration peeling occurred, where the vapor deposition film formed on the resin sheet 3 peeled off from the resin sheet 3. In Examples 7 and 9 in which H 2 O and the inert gas 10 were introduced into the vacuum chamber 1 together, a particularly strong adhesive strength was shown.

[0090] Figure 5 Using a polytetrafluoroethylene (PTFE) sheet as the resin sheet, the plasma treatment amount Q [kW / Fs] was set to be constant, and the evaluation results of film formation when introducing gas were changed.

[0091] In Comparative Example 2, the surface treatment of the present invention was not performed.

[0092] In Comparative Examples 3 to 5, surface treatment was performed using the existing apparatus shown in Figure 7 such that the plasma-inactive gas 10 collided with the resin sheet 3 with high kinetic energy.

[0093] In Examples 11 to 14 and Comparative Examples 3 to 5, the applied output of the high-frequency power supply 6 was set to 3 kW, and the inside of the vacuum chamber 1 was set to 1.0 Pa. In addition, the throughput Q was all 1.5 [kW / Fs].

[0094] In Example 11 and Comparative Example 3, the inactive gas 10 was set to N 2 , and H 2 O and N 2 were introduced into the vacuum chamber 1 together.

[0095] In Example 12, the inactive gas 10 was set to Ar, and H 2 O and Ar were introduced into the vacuum chamber 1 together.

[0096] In Example 13 and Comparative Example 4, the inactive gas 10 was set to N 2 , and N 2 was introduced into the vacuum chamber 1.

[0097] In Example 14 and Comparative Example 5, the inactive gas 10 was set to Ar, and Ar was introduced into the vacuum chamber 1.

[0098] After surface treatment of each example and each comparative example, a film was formed by sputtering, and then a copper thin film with a thickness of 25 μm was formed by wet electrolytic plating. R 0 is the surface resistance [Ω / □] of the Cu thin film with a thickness of 5 μm formed by sputtering, and F 90 [N / 2mm] is the force when the copper foil film is stretched in the 90-degree direction with respect to the bonding surface of the resin sheet 3, and is the tensile force [N] per width of 2 mm.

[0099] In Examples 11 and 12 in which H 2 O and the inactive gas 10 were introduced into the vacuum chamber 1 together, compared with Examples 13 and 14 in which only the inactive gas 10 was introduced into the vacuum chamber 1, F 90 [N / 2mm] is higher, indicating a stronger adhesion force.

[0100] However, strong adhesion was also shown in Comparative Examples 3 to 5. However, compared to Examples 11 to 14, the surface resistance [Ω / square] of the Cu thin film increased by one digit. This is considered to be because, in Comparative Examples 3 to 5, the inert gas 10 collided with the resin sheet 3 with high kinetic energy. Therefore, as the surface roughness of the resin sheet 3 increased, the adhesion improved, but the surface resistance of the Cu thin film increased due to the increase in surface roughness.

[0101] On the other hand, in Examples 11 to 14, since the surface resistance [Ω / square] of the Cu thin film was the same as that of Comparative Example 2 where no surface treatment was performed, it can be seen that the surface of the resin sheet 3 was not roughened, and the inert gas 10 acted with low kinetic energy.

[0102] Figure 6 It is a photograph showing the bonding surface of the resin sheet. Figure 6 (a) is Comparative Example 2. Figure 6 (b) is Example 11. Figure 6 (c) is Comparative Example 3, with a magnification of 5000 times.

[0103] Figure 6 (b) The Example 11 shown has the same surface roughness as Comparative Example 2 shown in (a). In contrast, it can be seen that Figure 6 (c) The Comparative Example 3 shown in (c) has fine recesses formed. Figure 6 (c) The Comparative Example 3 shown in (c) has fine recesses formed.

[0104] Thus, according to the resin sheet surface treatment method of the present invention, when a negative potential is applied, the plasmaized inert gas 10 moves toward the electrode with high kinetic energy. When no negative potential is applied, the plasmaized inert gas 10 acts on the bonding surface of the resin sheet 3 with low kinetic energy. Therefore, functional groups can be generated on the bonding surface without roughening the surface of the bonding surface of the resin sheet 3, and the adhesion of the thin film to the bonding surface in the film forming process can be improved. Moreover, when a copper thin film is bonded to the resin sheet 3 surface-treated by the resin sheet surface treatment method of the present invention, the copper thin film can be firmly adhered, and a copper thin film with smoothness can be formed. Therefore, the thin film surface resistance value of the copper thin film can be reduced, and the power loss of the copper thin film at high frequencies can be reduced. Furthermore, when pattern etching is performed on the resin sheet formed with a copper thin film, since the etched end face is smooth, a fine pattern can be formed, and the pattern accuracy can be improved.

[0105] In addition, in the existing device, the resin sheet 3 would be etched by the inert gas 10 with high kinetic energy E 2 As a result, the inside of the vacuum chamber 1 was contaminated, so cleaning was required, and the film forming process could not be performed in the same vacuum chamber 1. However, according to the resin sheet surface treatment method of the present invention, since the high kinetic energy E 2The inert gas 10 does not act on the resin sheet 3, so the film forming process can also be carried out in the same vacuum chamber 1 without being contaminated. In addition, in the existing device, since the high-frequency power supply (Rf power supply) 6 must be connected to the roller 4, the structure for high-voltage and high-frequency insulation is complicated, and thus the width of the roller 4 is also limited. However, according to the resin sheet surface treatment device of the present invention, such a restriction is not imposed.

[0106] In addition, the resin sheet 3 can be a single-piece sheet or a resin plate having a thickness of the resin sheet 3.

[0107] Industrial applicability

[0108] The present invention is applicable not only to the surface treatment of polyimide and polytetrafluoroethylene, but also to the surface treatment of other resins such as polyethylene terephthalate.

Claims

1. A method for surface treatment of a resin sheet, characterized in that, in this method, before the film-forming process of bonding a film to the surface of the resin sheet, a surface treatment process is performed on the bonding surface of the resin sheet to which the film is to be bonded, an inert gas is introduced into a vacuum chamber equipped with an electrode, the resin sheet is set to a ground potential, a negative potential is applied to the electrode by a high-frequency power supply that periodically applies a negative potential, when the negative potential is applied, the plasmaized inert gas moves toward the electrode with high kinetic energy, and when the negative potential is not applied, the plasmaized inert gas acts on the bonding surface of the resin sheet with low kinetic energy.

2. The method for surface treatment of a resin sheet according to claim 1, characterized in that, a plate-shaped electrode is used as the electrode, the plate-shaped electrode is made of a material that is difficult to etch.

3. The method for surface treatment of a resin sheet according to claim 1, characterized in that, the inside of the vacuum chamber is set to be 0.1 Pa or more and 10 Pa or less.

4. The method for surface treatment of a resin sheet according to claim 1, characterized in that, the resin sheet is a polyimide sheet, and the film is a copper film.

5. The method for surface treatment of a resin sheet according to any one of claims 1 to 3, characterized in that, the resin sheet is a polytetrafluoroethylene sheet, and the film is a copper film.

6. The method for surface treatment of a resin sheet according to any one of claims 1 to 3, characterized in that, Set the inert gas as N 2 , Introduce H 2 O into the vacuum chamber together with the N 2 .

7. A resin sheet surface treatment device, characterized in that, an electrode is arranged in a vacuum chamber, an inert gas is introduced into the vacuum chamber, and the bonding surface of the resin sheet is surface-treated, the resin sheet is set to a ground potential, a negative potential is applied to the electrode by a high-frequency power supply that periodically applies a negative potential, when the negative potential is applied, the plasmaized inert gas moves toward the electrode with high kinetic energy, and when the negative potential is not applied, the plasmaized inert gas acts on the bonding surface of the resin sheet with low kinetic energy.

8. The resin sheet surface treatment device according to claim 7, characterized in that, a plate-shaped electrode is used as the electrode, the plate-shaped electrode is made of a material that is difficult to etch.

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