JP2005116745A - Conductor coating polyimide film and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductor coating polyimide film and the manufacturing method thereof reduced in the number of pin holes in a conductor and capable of being manufactured stably in quality and inexpensively in a working cost, while high in a bonding strength between the conductor layer and a film at normal temperatures after retaining heating as a film for flexible wiring board and reduced in the variety of the quality thereof. <P>SOLUTION: Five processes of a process for dipping one side or both sides of the polyimide film (2) into the 0.05-10 wt.% water solution of water soluble amino silane coupling agent, next, a water washing process of the film surface at least one time or more, a dipping process into palladium-tin colloid catalyst solution, a dipping process into catalyst activating solution to remove tin and change the catalyst solution into metallic palladium, and a forming process of non-electrolytic plating layer (1) by effecting non-electrolytic metal plating, are processed sequentially and continuously to apply non-electrolytic plating so as to obtain the film thickness of the non-electrolytic plating layer (1) of not more than 10&mu;m. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

  The present invention relates to a method for producing a conductor-coated polyimide film and a conductor-coated polyimide film, and more specifically, a method for forming an electroless copper plating film conductor on a polyimide film that is a heat-resistant insulating resin, and is used in printed wiring board materials. The present invention relates to a method for producing a conductor-coated polyimide film useful as an electromagnetic wave shielding material and a conductor-coated polyimide film.

  Polyimide resin has excellent heat resistance and good mechanical, electrical and chemical properties, and is used as an insulating material for flexible printed circuit boards (FPC) and automatic tape bonding (TAB) substrates. Yes. For example, an aromatic polyimide film and a copper foil are bonded together with a thermosetting adhesive such as an epoxy resin to form a flexible substrate for FPC or TBA by a laminating method. In the flexible substrate by the laminate method, the insulation temperature deteriorates due to the problem of adhesive strength during heating that the temperature at which the adhesive strength of the copper foil can be maintained is low and the thermosetting adhesive layer is adsorbed to the thermosetting adhesive layer in the etching process. There was a problem of fear of doing. Therefore, an adhesive-free flexible substrate has been developed. As a method for producing a non-adhesive type flexible substrate, a method of directly depositing a metal layer on a polyimide film surface by sputtering, ion plating, vapor deposition or the like has been studied.

And the use of these flexible substrates is examined not only as a base material for circuit formation but also as a coverlay having a shield layer and an electromagnetic wave shielding material. Also, after applying polyamic acid, which is a polyimide precursor, on a copper foil, a method of imidizing polyamide to form a flexible substrate, or a polyimide having thermocompression bonding on one or both sides of a base layer made of aromatic polyimide A flexible substrate in which the insulating layer is entirely made of polyimide has been studied (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3). reference.).
Japanese Patent Laid-Open No. 10-075053 (page 2, page 3) Japanese Examined Patent Publication No. 7-102649 Japanese Patent No. 3152331

  In addition, as a method of performing electroless plating of wet plating with respect to the above-described dry plating method for directly coating a metal layer, the surface of polyimide represented by Japanese Patent No. 2622016 is chemically modified and electroless plating is performed. A method of performing heat treatment has also been studied. Among them, a method of chemical etching is necessary to give a palladium catalyst to the polyimide surface and perform uniform electroless plating (for example, JP-A-63-259083). A method using a silane coupling agent for adhesion is also reported in Japanese Patent No. 3277463 and Japanese Patent Application Laid-Open No. 2002-226972.

  In the above-described method of directly depositing a metal layer on the polyimide film surface by sputtering, ion plating, vapor deposition, etc., the copper layer can be formed by electroplating after the metal layer is deposited. A conductor layer with a thickness of less than 9 μm that is suitable for the formation of metal can be easily formed, and the bonding interface between the conductor layer and the polyimide film is flat. There was a problem that the strength was insufficient and a problem that the adhesive strength of the conductor layer during the heating and holding was significantly reduced.

  Further, when the metal layer is deposited, a minute pinhole is generated, which causes a problem of lack of the copper layer formed on the metal layer.

  On the other hand, after applying polyamic acid, which is a polyimide precursor, on a copper foil, a method of imidizing polyamide to form a flexible substrate, or a polyimide having thermocompression bonding on one or both sides of a base layer made of aromatic polyimide In the case of a method in which a sheet is laminated and this sheet and a copper foil are laminated and heat-bonded to form a flexible substrate in which the insulating layer is entirely made of polyimide, the copper foil is used. However, it was difficult to form a conductor layer having a thickness of less than 10 μm suitable for forming a fine pattern. Therefore, as a measure for improving the above circumstances, a method of coating a metal by electroless plating has been studied. However, it is possible to deposit the electroless plating stably and uniformly, which may adversely affect the work environment and the human body. However, there is a problem that it is difficult to eliminate the surface modification with a strong alkali, and the variation of the surface modification film layer is large and the physical properties such as the conductor strength are large.

  The present invention has been made in view of the above circumstances, and the object thereof is a conductor-coated polyimide film in which a conductor layer is formed on a film having an aromatic polyimide as a base layer, Provided is a method in which the thickness of the conductor layer can be easily formed to be less than 10 μm, the conductor has few pinholes, the work environment is good and the human body is not adversely affected, the quality is stable and the processing cost is low. In particular, for a flexible wiring board, a method for producing a conductor-coated polyimide film and a conductor-coated polyimide film having a high adhesive strength between a conductor layer and a film at room temperature and after heating and holding with little variation are provided. It is in.

  The inventor of the present application is a method in which the conductor coating method on the polyimide film is a method in which the metal layer is directly coated by electroless plating, and the polyimide film is immersed in an aqueous solution of a water-soluble aminosilane coupling agent and sufficiently washed with water. A single-layer coupling agent is applied to the surface, which captures the colloid by immersion in a Pd-Sn colloidal solution, and uniform electroless plating by applying a palladium catalyst is a simple continuous wet treatment and working environment It was found that it can be formed by a method that does not adversely affect the human body. Next, it is known that there is strength improvement due to the anchor effect by performing electroless plating on the mechanically roughened surface, which is integrated by weak bonding with this electroless plating, but the strength after heating and holding It was found that there was almost no decrease and a certain strength was maintained. Furthermore, it has been found that the electroless plating film via this coupling agent is very firmly connected without variation by heating in an inert atmosphere. This is different from the conventionally known strengthening of connection by heat-improving re-imide by heating of the hydrophilic layer due to chemical modification of polyimide. However, it was also found that strengthening the heat adhesion of the electroless plating film via this coupling agent causes a decrease in strength after heat retention due to copper oxidation. Combining these findings, a mechanically roughened polyimide film that has been electrolessly plated via a coupling agent, heated in an inert atmosphere, has a sufficient bonding strength even after initial and after heating. It has been found that this is high, and the present invention has been achieved.

  Specifically, the method for producing a conductor-coated polyimide film according to claim 1 of the present invention includes a step of immersing one or both sides of a polyimide film in a 0.05 to 10% by weight aqueous solution of a water-soluble aminosilane coupling agent. Next, a step of washing the film surface with water at least once, a step of immersing in a palladium-tin colloidal catalyst solution, a step of immersing in a catalytically active solution that removes tin and changes to metallic palladium, and electroless metal plating It is characterized by performing the electroless plating so that the film thickness of the electroless plating layer is 10 μm or less by sequentially processing the five steps of forming the electroless plating layer sequentially.

  In the method for producing a conductor-coated polyimide film according to claim 2 of the present invention, after electroless plating is performed through the water-soluble aminosilane coupling agent, heating is performed to 200 ° C. or higher in an inert atmosphere or vacuum. The normal conductor bonding strength is 0.5 kg / cm or more without a polyimide surface chemical modification layer such as an alkaline solution.

  The method for producing a conductor-coated polyimide film according to claim 3 of the present invention is a polyimide in which one or both sides of the polyimide film are formed by mechanical blasting of sandblast with a surface roughness of 0.04 <Ra <0.50 μm. It is characterized by being a film.

  The method for producing a conductor-coated polyimide film according to claim 4 of the present invention is characterized in that after the electroless plating is performed, electrolytic copper plating is further performed to deposit an electrolytic copper plating layer to a desired thickness.

  A conductor-coated polyimide film according to a fifth aspect of the present invention is characterized by being manufactured using the method for producing a conductor-coated polyimide film according to any one of the first to fourth aspects.

  According to the method for producing a conductor-coated polyimide film according to claims 1 to 4 of the present invention, the thickness of the conductor layer can be easily formed to be less than 10 μm, the conductor has few pinholes, and the human environment is adversely affected in a good working environment. It is intended to provide products that are stable in quality and can be manufactured at low processing costs. Furthermore, for flexible wiring boards, the adhesive strength between the conductor layer and the film at room temperature and after being heated is maintained. Therefore, it is possible to produce a conductor-coated polyimide film that is high and can prevent variation.

  According to the conductor-coated polyimide film according to claim 5 of the present invention, the conductor-coated polyimide film is manufactured using the method for manufacturing a conductor-coated polyimide film according to any one of claims 1 to 4. The object is to provide a method that can be easily formed to be less than 10 μm, has few pinholes in the conductor, does not adversely affect the human body with a good work environment, is stable in quality, and can be manufactured at low cost. For a flexible wiring board, a conductor-coated polyimide film that has a high adhesive strength between the conductor layer and the film at room temperature and after being heated and can be prevented from varying.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view for explaining a conductor-coated polyimide film manufacturing method and a conductor-coated polyimide film according to an embodiment of the present invention. FIG. 2 is a cross-sectional view for explaining a conductor-coated polyimide film manufacturing method and a conductor-coated polyimide film according to another embodiment of the present invention.

  In the method for producing a conductor-coated polyimide film of the present invention, as shown in FIG. 1, a step of immersing one or both sides of a polyimide film (2) in a 0.05 to 10% by weight aqueous solution of a water-soluble aminosilane coupling agent; Next, a step of washing the film surface with water at least once, a step of immersing in a palladium-tin colloidal catalyst solution, a step of immersing in a catalytically active solution that removes tin and changes to metallic palladium, and electroless metal plating The five steps of the step of forming the electroless plating layer (1) are successively and sequentially performed, and the electroless plating is performed so that the film thickness of the electroless plating layer (1) is 10 μm or less.

  Moreover, as shown in FIG. 2, after performing the said electroless-plating, electrolytic copper plating may be further performed and the electrolytic copper plating layer (3) may be deposited to desired thickness.

  Hereinafter, the present invention will be described in detail.

  The polyimide film used in the present invention is an aromatic polyimide which is an aromatic tetracarboxylic acid or a derivative thereof. It is a polyimide obtained from aromatic tetracarboxylic acids and aromatic diamines. Examples of the aromatic tetracarboxylic acid and acids include pyromellitic acid, 3,3,4,4-biphenyltetracarboxylic acid, one or two combinations of 3,3,4,4-benzophenonetetracarboxylic acid, aromatic 1 type, or 2 types of combinations of group diamine phenylenediamine and 4, 4- diamino diphenyl ether are mentioned.

  In particular, pyromellitic dianhydride is used as the aromatic tetracarboxylic acid, aromatic polyimide using diaminodiphenyl ether as the aromatic diamine, and 3,3 ′, 4,4′-biphenyltetra as the aromatic tetracarboxylic acid. An aromatic polyimide using a carboxylic dianhydride and using phenylenediamine as an aromatic diamine is preferable from the viewpoint of heat resistance, mechanical strength, and dimensional stability.

  Further, it may be a thermoplastic polyimide film or a laminated film of the above-mentioned aromatic polyimide and thermoplastic polyimide. Since these have softening adhesiveness by heating, a stronger connection can be obtained.

  As the thermoplastic polyimide resin, a polymer having an imide structure in the main chain and having a glass transition temperature, preferably in a range of 150 to 350 ° C., and at this glass transition temperature, an elastic modulus rapidly decreases. say. For example, these polyimides also include polyimides obtained from aromatic tetracarboxylic acids which are aromatic aromatic tetracarboxylic acids or derivatives thereof and aromatic diamines.

  For example, as an aromatic tetracarboxylic acid component, benzophenonetetracarboxylic dianhydride, pyromellitic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4 Examples of aromatic diamine components include diaminodiphenyl ethers, di (aminophenoxy) benzenes, bis (aminophenoxyphenyl) sulfones, bis (aminophenoxyphenyl) propanes, and bis-tetraphenyl dianhydrides. It is composed of (aminophenoxy) benzenes.

  In particular, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride biphenyltetracarboxylic acids and aromatic diamines include a plurality of Those having a benzene ring are desirable.

  As a method for producing a sheet in which a thermoplastic resin layer is laminated on a base layer made of aromatic polyimide, a method of applying a thermoplastic resin to a base layer made of aromatic polyimide and heating and integrating them, Examples thereof include a method of co-extrusion and integration using an extrusion molding machine having two or more layers of extrusion dies as disclosed in Japanese Patent Publication No. 7-102649.

In the present invention, these polyimide films are immersed in an aqueous solution of a water-soluble aminosilane coupling agent. The water-soluble aminosilane coupling agent is represented by the general formula NH ₂ —R—Si (OR ′) _{3. For} example, γ-aminopropyltrimethoxysilane: γ-aminopropyltriethoxysilane: N-β ( Aminoethyl) γaminopropyltrimethoxysilane N-β (aminoethyl) γaminopropyltriethoxysilane: γ-ureidopropyltriethoxysilane. N-β (aminoethyl) γ aminopropyltriethoxy (or methoxy) silane is desirable to stabilize from the hydrophilicity and hydrolyzability of the aqueous solution.

  The concentration of the aqueous solution is such that the amount of the coupling agent single molecule adhering to the surface of the polyimide film is an appropriate amount. An excessive amount of deposition causes uneven deposition and a decrease in insulation resistance. Preferably it is 0.2 to 0.8 weight%. The liquid temperature and treatment time are not particularly limited, but the immersion is preferably performed at 25 ° C. for about 30 seconds to 1 minute. Prior to this treatment of the film, an alcohol or acid degreasing / cleaning step for removing fats and oils may be included.

  In particular, dry reforming treatment such as plasma for making the surface hydrophilic need not be performed in advance. Washing with water after the coupling agent treatment is an indispensable step, and one may eliminate unevenness in the coupling agent treatment, but mixing of the coupling agent other than that applied to the polyimide into the palladium-tin colloidal solution Since the agent reacts with the colloid and the palladium-tin colloid coagulates and precipitates, and the catalyst adhesion action is lost, this is a water washing step for eliminating the carry-in of the cockling agent.

  Next, immersion in a palladium-tin colloid solution, washing in water / accelerator solution, washing in water, and immersion in an electroless plating solution are performed. The bath solution and conditions may be a commercially available plating system. When the electroless copper plating film thickness is 10 μm or more, it takes a long time and the production is not practical. Preferably it is 0.1-1 micrometer.

  Here, the electroless plating is mainly copper plating, but electroless plating using another pd catalyst as an action is also possible. The adhesion strength by this electroless plating alone is integrated with a weak bond of 0.5 kg / cm at most, but the strength can be used sufficiently depending on the application.

  As a material for a flexible wiring board, the following process is performed because higher bonding strength is required.

  Blasting is performed as a mechanical process on a polyimide film, one of which is plated. The drive blast method or wet blast method is used for blasting, and the range of Ra 0.04 to 0.50 μm is effective as the surface roughness. When Ra is 0.04 μm or less, sufficient strength due to roughening cannot be secured. On the other hand, if Ra is 0.5 μm or more, the abrasive grains shot by the blast become too large, and the partial variation of the rough surface becomes too large to be stable. Preference is given to using a grain size of # 800 and roughening to Ra 0.10 to 0.30 μm.

  Due to the roughening by blasting described above, the joint strength of the conductor made by electroless copper and copper conductor thickness of 18 μm by electrolytic copper plating is about 0.5 kg / cm, and the joint strength after heating at 150 ° C. for 168 hours is also 0.5 kg. / Cm and no decrease was observed.

  The other is that the adhesive strength is greatly increased by heating the copper-coated polyimide film subjected to electroless copper plating via a coupling agent to 200 ° C. or higher in an inert or vacuum atmosphere.

  When the heating temperature is 200 ° C. or lower, the reaction between the coupling agent, the resin, and copper does not occur and the strength does not increase. Further, the upper limit of heating may be not higher than the thermal decomposition temperature of the resin, but a good adhesion state is preferably 450 ° C. or lower.

  In order to prevent thermal deterioration of the electroless plating film, the atmosphere is preferably heated in a vacuum having an oxygen concentration of 100 PPm or less or in an inert gas atmosphere such as nitrogen gas, neon gas, argon gas. Although there is no restriction | limiting in particular about heating time, For example, it can carry out within the range of 5 minutes-5 hours.

  Conductor-coated polyimide with mechanical Ra = 0.20 roughened and electroless copper plated 0.3 μm in blast, heat treated at 350 ° C. for 1 hour in an inert atmosphere or vacuum, and then electrolytic copper plated Since the film forms the copper layer by plating, the thickness of the conductor layer can be easily reduced. In addition, a dense film formed by electroless plating hardly generates pinholes, has high adhesion strength between the conductor layer and the film at room temperature and after heating, has little variation, and has a good work environment. It can be produced by a method that does not adversely affect the process.

  In addition, the conductor-coated polyimide substrate obtained as described above can be easily formed with a conductor layer thickness of less than 10 μm, has few pinholes in the conductor, has a good work environment, and does not adversely affect the human body. Stable and inexpensive processing costs can be provided, and for flexible wiring boards, the bonding strength between the conductor layer and the film at room temperature and after heating is high, and variations are reduced. It is something that can be done.

  Hereinafter, the present invention will be described in more detail with reference to Examples 1 to 4 and Comparative Examples 1 to 4 shown below.

(Example 1)
A polyimide film (250 mm width, 25 μm thickness, manufactured by Toray DuPont, trade name “Kapton 100V type”) made of aromatic polyimide obtained by using pyrometic dianhydride and diaminodiphenyl ether is made into 200 mm square, and is water-soluble. As an aminosilane coupling agent, N-β (aminoethyl) γaminopropyltrimethoxysilane (manufactured by Chisso Corporation, trade name: Silaace S320) was immersed in an aqueous solution of 0.5% by weight at 25 ° C. for 1 minute. Next, immerse in ion-washed water primary, secondary, and tertiary water for 30 seconds each and immerse in palladium-tin colloid type AT-105 activating solution manufactured by Uemura Kogyo Co., Ltd. at 25 ° C. for 5 minutes. After applying the catalyst and washing with water, it was subjected to an acceleration treatment for 3 minutes at 25 ° C. using a Sulcup AL-106 accelerator manufactured by Uemura Kogyo Co., Ltd. Then, an electroless copper plating film having a uniform gloss thickness of 0.1 μm was obtained evenly on the polyimide film surface by rocking immersion for 3 minutes at a bath load of 0.4 dm ² / l and a deposition rate of 2.0 μm / hr. . The conductor-coated polyimide film thus obtained had good adhesion without peeling off with a cellophane tape.

(Example 2)
Using the hot air circulating heating furnace (manufactured by Koyo Thermo System Co., Ltd.), the polyimide film having the electroless copper plating film produced in Example 1 described above is 5 ° C./min in a nitrogen gas atmosphere having an oxygen concentration of 100 ppm or less. Was heated to 350 ° C. at a temperature increase rate of 1 ° C., held at 350 ° C. for 1 hour, and then heat-treated by cooling at a temperature decrease rate of 5 ° C./min.

Next, a copper layer having a thickness of 8 μm was formed by electroplating on the electroless copper plating thin film of the sheet-like film after the heat treatment to obtain a conductor-coated polyimide film. The electroplating conditions were a plating bath containing 100 g / liter CuSO ₄ .5H ₂ O and 150 g / liter H ₂ SO ₄ , a plating temperature of 25 ° C., and a plating time of 30 minutes.

  A strip-shaped conductor layer pattern having a width of 3 mm and a length of 100 mm is formed on the obtained conductor-coated polyimide film, and the end portion of the conductor layer is peeled off in a direction perpendicular to the conductor-coated polyimide substrate to peel off the conductor layer. The strength (adhesive strength) was measured.

  The peel strength (adhesive strength) at room temperature (25 ° C.) is 0.8 kgf / cm (7.8 N / cm), and the peel strength (adhesive strength) after holding in a 150 ° C. atmosphere for 168 hours is 0.2 kgf. / Cm (2.0 N / cm).

  Moreover, the one side conductor of the obtained conductor covering polyimide film was etched, cut out to 125 × 12 cm, and the presence or absence of a pinhole was confirmed by applying light from one side of the copper coating layer side. There was no light transmission, and no pinholes were observed.

(Example 3)
As a sheet in which a thermoplastic resin layer is laminated on a substrate layer made of aromatic polyimide, 250 sheets are formed on both surfaces of the substrate layer made of aromatic polyimide obtained using biphenyltetracarboxylic dianhydride and aromatic diamine. 25 μm thick sheet with a glass transition temperature of ℃ (measured by a method using a differential scanning calorimeter) and a thermoplastic polyimide layer of about 3 μm thick laminated and integrated (Ube Industries, Ltd.) Using the 200 mm square of the product name “UPILEX VT film”), adjust the pressure and shot time so that Ra = 0.15 using abrasive grain alumina # 800 with a sandblasting device one by one. Both sides were roughened. Using the film, a wet electroless plating treatment system was performed in the same manner as in Example 1 to obtain an electroless copper plating film having a thickness of 0.1 μm, which is matte. On the electroless copper plating thin film, a copper layer having a thickness of 8 μm was formed by electroplating to obtain a conductor-coated polyimide film. The measuring method of electroplating conditions and conductor adhesive strength was performed similarly to Example 2 mentioned above.

  The peel strength (adhesive strength) at room temperature (25 ° C.) is 0.5 kgf / cm (4.9 N / cm), and the peel strength (adhesive strength) after holding in a 150 ° C. atmosphere for 168 hours is 0.00. It was 6 kgf / cm (5.9 N / cm).

Example 4
A conductor-coated polyimide film obtained only in the electroless copper plating produced in Example 3 described above was obtained under the same heat treatment conditions and electroplating conditions as in Example 2 described above.

  The peel strength (adhesive strength) at normal temperature (25 ° C.) is 1.8 kgf / cm (17.6 N / cm), and the peel strength (adhesive strength) after holding in a 150 ° C. atmosphere for 168 hours is 1. 1. kgf / cm (10.8 N / cm).

(Comparative Example 1)
Although the process of water-soluble aminosilane coupling agent treatment was not carried out and the catalyst application / activation / electroless process was carried out in the same manner as in Example 1 described above, even when immersed for 20 minutes in an electroless copper plating solution The plating film did not precipitate.

(Comparative Example 2)
Instead of the water-soluble aminosilane coupling agent treatment step, the surface hydrophilizing agent RO (C ₂ H ₄ O) _n C ₃ H ₆ Si (OR ′) ₃ silane monomer (manufactured by Nihon Unicar: trade name NUC SILICONES A) -1230) and a mercaptosilane coupling agent γ-mercaptopropyltrimethoxysilane (manufactured by Nippon Unicar Co., Ltd .: trade name NUC SILICONES A-189) methanol / water = 50: 50 mixed liquid imidazole silane coupling agent (manufactured by Japan Energy) : Product name IA-100A) was treated with 0.5% by weight, respectively, and the catalyst application, activation, and electroless processes were performed in the same manner as in Example 1 described above. Although it was immersed in an electroless copper plating solution for 5 minutes, plating was deposited only on a part of the polyimide film surface.

(Comparative Example 3)
Using the hot air circulating heating furnace (manufactured by Koyo Thermo System Co., Ltd.), the polyimide film having the electroless copper plating film produced in Example 1 described above is 5 ° C./min in a nitrogen gas atmosphere having an oxygen concentration of 100 ppm or less. Was heated to 180 ° C. at a temperature increase rate of 1 ° C., held at 180 ° C. for 1 hour, and then heat-treated by cooling at a temperature decrease rate of 5 ° C./min. Similar to Example 2, an electrolytic copper plating with a thickness of 8 μm was performed, but the copper film was easily peeled off from the polyimide film.

(Comparative Example 4)
A 25 μm-thick high heat-resistant polyimide film (product name “Kapton 100V” manufactured by Toray DuPont) was cut into a size of 12 × 12 cm, and nickel was formed into a thickness of 100 mm on one side by a sputtering method. Copper was coated to a thickness of 0.1 μm to form a first metal layer, and then a copper layer having a thickness of 8 μm was formed under the same conditions as the electroplating conditions of Example 1 described above.

  The peel strength of a flexible wiring board having a copper thickness of 8 μm connected by sputtering was 0.55 kgf / cm in a normal state, and the peel strength after holding at 150 ° C. for 168 hours was 0.15 kgf / cm.

  In addition, when a copper-coated polyimide film with a conductor thickness of 8 μm was cut out to 12 × 12 cm and light was applied from one side of the copper coating layer to confirm the presence or absence of pinholes, There was transmission and the presence of pinholes was observed. As for the size of the pinhole, the diameter was several tens to one hundred and several tens of μm, and the number was 2 to 3 pieces / 2.5 cm square.

  Using this copper-coated polyimide film, a flexible wiring board having a wiring width of 40 μm and a wiring pitch of 100 μm was produced, and defects such as chipping or disconnection due to pinholes were confirmed in the wiring portion.

It is sectional drawing for demonstrating the manufacturing method of the conductor covering polyimide film which concerns on one Embodiment of this invention, and a conductor covering polyimide film. It is sectional drawing for demonstrating the manufacturing method of the conductor covering polyimide film which concerns on other one Embodiment of this invention, and a conductor covering polyimide film.

Explanation of symbols

1 Electroless plating layer 2 Polyimide film 3 Electrolytic copper plating layer

Claims (5)

A step of immersing one or both sides of a polyimide film in a 0.05 to 10% by weight aqueous solution of a water-soluble aminosilane coupling agent, a step of washing the film surface with water at least once, and a step of immersing in a palladium-tin colloid catalyst solution 5 steps of removing the tin, immersing it in a catalytically active solution that changes to metallic palladium, and forming an electroless plating layer by performing electroless metal plating sequentially, A method for producing a conductor-coated polyimide film, wherein electroless plating is performed so that the thickness of the electrolytic plating layer is 10 μm or less. After conducting electroless plating through the water-soluble aminosilane coupling agent, it is heated to 200 ° C. or higher in an inert atmosphere or vacuum, so that a normal conductor without a polyimide surface chemical modification layer such as an alkaline solution is obtained. 2. The method for producing a conductor-coated polyimide film according to claim 1, wherein the bonding strength is 0.5 kg / cm or more. 3. The polyimide film according to claim 1, wherein one or both sides of the polyimide film are polyimide films formed by mechanical blasting of sandblast with a surface roughness of 0.04 <Ra <0.50 μm. A method for producing a conductor-coated polyimide film. The method for producing a conductor-coated polyimide film according to any one of claims 1 to 3, wherein after the electroless plating is performed, electrolytic copper plating is further performed to deposit an electrolytic copper plating layer to a desired thickness. . A conductor-coated polyimide film produced by using the method for producing a conductor-coated polyimide film according to any one of claims 1 to 4.

Images