JP2008290301A - Copper-clad plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper-clad plate which has slidability by generating surface projections by adding fine inorganic particles, uses a polyimide film applicable to a flexible printed circuit board (FPC) and a chip-on film (COF) type automatic optical inspection system (AOI), and thus is suitable for a high performance flexible printed circuit board. <P>SOLUTION: In the copper-clad plate, the polyimide film in which the inorganic particles having a particles size of 0.01-1.5 μm, an average particles size of 0.05-0.7 μm, and a particle size distribution wherein particles 0.15-0.60 μm in particle size occupy at least 80 vol% of the total volume of the particles are dispersed and contained in a ratio of 0.1-0.9 wt.% of the weight of a film resin is used, and on at least one side of the polyimide film, a copper layer is formed directly without using an adhesive. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a copper-clad board suitable as a material for flexible printed wiring boards (FPC) and chip-on-film (COF) used in the field of electrical and electronic equipment, and more specifically, inorganic fine particles are added. The present invention relates to a copper-clad plate made of a polyimide film that is easily slidable by generating surface protrusions and is adaptable to an automatic optical inspection system (AOI).

  Polyimide films are known to have excellent properties in heat resistance, cold resistance, chemical resistance, electrical insulation, mechanical strength, etc., and electrical insulation materials for wires, heat insulating materials, flexible printed wiring boards (FPC) And widely used for chip-on-film (COF) base films, carrier tape films for IC tape automated bonding (TAB), IC lead frame fixing tapes, and the like.

  An important practical characteristic when a polyimide film is used in these applications is the slipperiness (slidability) of the film. That is, in various film processing steps, the slidability between the film support (for example, roll) and the film, and the slidability between the films are secured, thereby improving the operability and handling in each step, Furthermore, there is an effect that it is possible to avoid the occurrence of defective parts such as wrinkles on the film.

  On the other hand, the flexible printed wiring board, which is the main use of polyimide film, is usually bonded to copper foil via various adhesives. Polyimide has its chemical structure and chemical resistance (solvent) stability. In many cases, the adhesiveness to the copper foil is insufficient, and at present, the polyimide film is subjected to a surface treatment (alkali treatment, corona treatment, plasma treatment, sandblast treatment, etc.) and used for adhesion.

  In addition, with the recent finer pitch of electronic parts, especially in the inspection of COF, inspection of line width, foreign matter, etc. by visual inspection has been mainstream so far, but an automatic optical inspection system (AOI) will be introduced. After that, the heat-resistant film produced by the conventional formulation mixed with the inorganic powder was sufficiently satisfactory in terms of running properties, but in the AOI, the inorganic powder is too large, Along with the recent narrowing of the COF pitch, the particles may be erroneously detected as foreign matter, which has been a major obstacle to automatic inspection systems.

  In the conventional smoothing technology for polyimide films, an inert inorganic compound (for example, alkaline earth metal orthophosphate, dibasic calcium phosphate anhydride, calcium pyrophosphate, silica, talc) is added to polyamic acid (Patent Document 1). Further, a method of performing plasma treatment after forming fine protrusions on the film surface with fine particles (see Patent Document 2) is known. However, these particles have a problem that they have a large particle size and cannot be applied to an automatic optical inspection system.

In addition, inorganic particles having an average particle diameter of 0.01 to 100 μm are embedded / held in the polyimide surface layer, and a plurality of protrusions made of the inorganic particles partially exposed are formed on the film. A method (see Patent Document 3) in which 1 × 10 to 5 × 10 ⁸ pieces / mm ² are present on the surface layer is known. In this method, the inorganic particles are positively exposed on the surface, and the friction coefficient on the film surface is reduced to effectively obtain the slipperiness effect. However, the inorganic particles are partially exposed. However, there was a problem that scratches occurred on the surface of the other film in contact with this, resulting in poor appearance.
JP-A-62-68852 JP 2000-191810 A Japanese Patent Laid-Open No. 5-25295

  The present invention has been achieved as a result of studying the solution of the problems in the prior art described above as an issue.

  Accordingly, an object of the present invention is to provide easy slipping by generating surface protrusions by adding inorganic fine particles, and furthermore, an automatic optical inspection system for flexible printed circuit boards (FPC) and chip-on-film (COF) ( An object of the present invention is to provide a copper-clad plate suitable for a high-performance flexible printed circuit board using a polyimide film applicable to AOI).

  In order to achieve the above object, according to the present invention, the polyimide film has a particle size of 0.01 to 1.5 μm, an average particle size of 0.05 to 0.7 μm, and a particle size of 0.15. Polyimide film in which inorganic particles having a particle size distribution in which particles of ˜0.60 μm account for 80 volume% or more of all particles are dispersed and contained at a ratio of 0.1 to 0.9 wt% per film resin weight A copper-clad board is provided in which a copper layer is directly formed on one or both surfaces of this polyimide film without using an adhesive.

In the copper-clad plate of the present invention,
Protrusions resulting from the inorganic particles are present on the surface of the polyimide film, and the number of protrusions having a size of 20 μm or more is 1 piece / 40 cm square or less,
The number of protrusions having a height of 2 μm or more present on the surface of the polyimide film is 5 pieces / 40 cm square or less, and the number of protrusions having a size of 20 μm or more present on the surface of the copper layer formed on the surface of the polyimide film. Is preferably 40 pieces / 10 cm square or less.

  According to the present invention, as will be described below, it is easy to slip by adding inorganic fine particles to generate surface protrusions, and further, an automatic flexible printed circuit board (FPC) or chip-on-film (COF) A copper-clad board suitable for a high-performance flexible printed circuit board using a polyimide film applicable to an optical inspection system (AOI) can be obtained.

  Hereinafter, the present invention will be described in detail.

  The copper-clad board of this invention uses a polyimide film as a base material, and a copper layer is directly formed on one or both sides of this polyimide film without an adhesive.

  In the copper-clad plate of the present invention, the polyimide film used as a substrate is mainly composed of one or more selected from paraphenylenediamine, 4,4′-diaminodiphenyl ether, and 3,4′-diaminodiphenyl ether as a diamine component. As an acid dianhydride component, pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride It is mainly composed of one or more selected from products. With these combinations, it is possible to keep the coefficient of linear expansion required as a copper-clad board low, to keep the moisture content low, and to keep the heat shrinkage rate low. In addition to these components, a small amount of diamine or acid dianhydride may be added. Specific examples of diamines and acid dianhydrides include, but are not limited to:

(1) Acid dianhydride 2,3 ′, 3,4′-biphenyltetracarboxylic dianhydride, 2,3,6,7-naphthalenedicarboxylic dianhydride, 2,2-bis (3,4 Dicarboxyphenyl) ether, pyridine-2,3,5,6-tetracarboxylic dianhydride, 1,2,4,5-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic Acid dianhydride, 1,4,5,8-decahydronaphthalenetetracarboxylic dianhydride, 4,8-dimethyl-1,2,5,6-hexahydronaphthalenetetracarboxylic dianhydride, 2,6 -Dichloro-1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,7-dichloro-1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-tetra Chloro-1,4,5,8-naphthale Tetracarboxylic dianhydride, 1,8,9,10-phenanthrenetetracarboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, 1,1-bis (3 4-dicarboxyphenyl) ethane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4 -Dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, benzene-1,2,3,4-tetracarboxylic dianhydride, 3,4,3 ', 4 '-Benzophenone tetracarboxylic dianhydride and the like.

(2) Diamine 3,3′-diaminodiphenyl ether, metaphenylenediamine, 4,4′-diaminodiphenylpropane, 3,4′-diaminodiphenylpropane, 3,3′-diaminodiphenylpropane, 4,4′-diaminodiphenylmethane 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, benzidine, 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4 ' -Diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 2,6-diaminopyridine, bis- (4-aminophenyl) diethylsilane, 3,3'-dichlorobenzidine, Bis- (4-aminophenyl) ethyl Sufinoxide, bis- (4-aminophenyl) phenylphosphinoxide, bis- (4-aminophenyl) -N-phenylamine, bis- (4-aminophenyl) -N-methylamine, 1,5- Diaminonaphthalene, 3,3′-dimethyl-4,4′-diaminobiphenyl, 3,4′-dimethyl-3 ′, 4-diaminobiphenyl 3,3′-dimethoxybenzidine, 2,4-bis (p-β -Amino-tert-butylphenyl) ether, bis (p-β-amino-tert-butylphenyl) ether, p-bis (2-methyl-4-aminopentyl) benzene, p-bis- (1,1-dimethyl) -5-aminopentyl) benzene, m-xylylenediamine, p-xylylenediamine, 1,3-diaminoadamantane, 3,3'-diamino-1,1'-diaminoadamer Nanthane, 3,3′-diaminomethyl 1,1′-diadamantane, bis (p-aminocyclohexyl) methane, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, 3-methylhepta Methylenediamine, 4,4′-dimethylheptamethylenediamine, 2,11-diaminododecane, 1,2-bis (3-aminopropoxy) ethane, 2,2-dimethylpropylenediamine, 3-methoxyhexaethylenediamine, 2,5 -Dimethylhexamethylenediamine, 2,5-dimethylheptamethylenediamine, 5-methylnonamethylenediamine, 1,4-diaminocyclohexane, 1,12-diaminooctadecane, 2,5-diamino-1,3,4-oxadi Azole, 2,2-bis 4-aminophenyl) hexafluoropropane, N-(3- aminophenyl) -4-aminobenzamide, 4-aminophenyl-3-aminobenzoate and the like.

  In the present invention, specific examples of the organic solvent used for forming the polyamic acid solution that is a precursor of the polyimide film include, for example, sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, N, N-dimethylformamide, Formamide solvents such as N, N-diethylformamide, acetamide solvents such as N, N-dimethylacetamide, N, N-diethylacetamide, pyrrolidones such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone Examples include solvents, phenolic solvents such as phenol, o-, m-, or p-cresol, xylenol, halogenated phenol, and catechol, and aprotic polar solvents such as hexamethylphosphoramide and γ-butyrolactone. These alone Although it is desirable to use as a mixture, further xylene, the use of aromatic hydrocarbons such as toluene are also possible.

Any of the following known methods (1) to (5) can be adopted as a method for polymerizing polyimide. That is,
(1) A method in which the entire amount of the aromatic diamine component is first put in a solvent, and then the aromatic tetracarboxylic acid component is added so as to be equivalent to the total amount of the aromatic diamine component and polymerized.
(2) A method in which the whole amount of the aromatic tetracarboxylic acid component is first put in a solvent, and then the aromatic diamine component is added in an amount equal to the amount of the aromatic tetracarboxylic acid component for polymerization.
After mixing for a time required for the reaction at a ratio of 95 to 105 mol% of the carboxylic acid compound, the other aromatic diamine compound is added, and then the aromatic tetracarboxylic acid compound is converted into the total aromatic diamine component and the total aromatic A method of adding and polymerizing the tetracarboxylic acid components of the aromatic group so as to be substantially equal.
(4) After placing the aromatic tetracarboxylic acid compound in the solvent, the aromatic tetracarboxylic acid compound is mixed for a time required for the reaction at a ratio of 95 to 105 mol% of one aromatic diamine compound with respect to the reaction component, and then the aromatic tetracarboxylic acid compound is mixed. A method in which a carboxylic acid compound is added, and then the other aromatic diamine compound is added and polymerized so that the total aromatic diamine component and the total aromatic tetracarboxylic acid component are approximately equal.
(5) A polyamic acid solution (A) is prepared by reacting one aromatic diamine component with an aromatic tetracarboxylic acid in a solvent so that either one becomes excessive, and the other aromatic diamine in another solvent. The polyamic acid solution (B) is prepared by reacting the component and the aromatic tetracarboxylic acid so that either one becomes excessive. A method of mixing the polyamic acid solutions (A) and (B) thus obtained to complete the polymerization. At this time, when adjusting the polyamic acid solution (A), if the aromatic diamine component is excessive, the polyamic acid solution (B) contains excessive aromatic tetracarboxylic acid component, and the polyamic acid solution (A) contains aromatic tetracarboxylic acid. When the acid component is excessive, the polyamic acid solution (B) makes the aromatic diamine component excessive, and the polyamic acid solutions (A) and (B) are combined to form the wholly aromatic diamine component and wholly aromatic compound used in these reactions. Adjustment is made so that the amount of the tetracarboxylic acid component is approximately equal.

  The polymerization method is not limited to these, and other known methods may be used.

  The polyamic acid solution thus obtained contains a solid content of 5 to 40% by weight, preferably 10 to 30% by weight, and its viscosity is 10 to 2000 Pa · s as measured by a Brookfield viscometer, preferably 100-1000 Pa · s is preferably used for stable liquid feeding. Moreover, the polyamic acid in the organic solvent solution may be partially imidized.

  Next, the manufacturing method of the polyimide film of this invention is demonstrated.

  As a method for forming a polyimide film, a polyamic acid solution is cast into a film and thermally decyclized and desolvated to obtain a polyimide film, and a polyamic acid solution is mixed with a cyclization catalyst and a dehydrating agent. The method of obtaining a polyimide film by preparing a gel film by decyclization and heating it to remove the solvent is mentioned, but the latter is preferable because the linear expansion coefficient of the obtained polyimide film can be kept low. .

  In the present invention, it is essential to add inorganic particles to the polyimide film in order to improve the running property (slidability) of the film.

  In such inorganic particles, the powder particle diameter is in the range of 0.01 to 1.5 μm, and the average particle diameter is in the range of 0.05 to 0.7 μm, more preferably 0.1 to 0. In the range of .6 μm, and even more preferably in the range of 0.3 to 0.5 μm, in which case the polyimide film can be adapted without problems to inspection with automatic optical inspection systems. Alternatively, the film can be used without causing deterioration of the mechanical properties of the film. If the average particle size is lower than these ranges, sufficient slipperiness to the film cannot be obtained, and if it exceeds the average, inorganic particles are judged as foreign substances by an automatic inspection system, which is not preferable. .

  The content of the inorganic particles is preferably from 0.1 to 0.9% by weight per film resin weight, and more preferably from 0.3 to 0.8% by weight. If the amount is 0.1% by weight or less, the film surface is insufficient in number of protrusions, so that sufficient slipperiness to the film cannot be obtained, the transportability is deteriorated, and the film winding shape when wound on a roll is also deteriorated. Therefore, it is not preferable. Further, if it is 0.9% by weight or more, the slipperiness of the film is improved, but coarse protrusions due to abnormal aggregation of particles increase, and this is judged to be a foreign matter by an automatic inspection system, resulting in an obstacle. Absent.

  The surface protrusions of the inorganic particles also increase the film surface area, and the surface is sufficiently roughened so that the anchor effect is observed and the adhesiveness is not impaired.

  In the particle size distribution of the inorganic particles, it is preferable that the particle size distribution is narrow, that is, the proportion of particles having a similar size in all particles is high. Specifically, all particles having a particle size of 0.15 to 0.60 μm are all present. It is preferable to occupy a ratio of 80% by volume or more in the particles. If the proportion of particles below this range and 0.15 μm or less increases, the slipperiness of the film decreases, which is not preferable. In addition, when sending inorganic particles, coarse particles can be removed with a 5 μm cut filter or a 10 μm cut filter. However, when the proportion of particles of 0.60 μm or more increases, the filter frequently clogs. This is not preferable because the process stability is deteriorated and coarse aggregation of particles tends to occur.

  In the film surface protrusion caused by the inorganic particles, the number of protrusions having a size of 20 μm or more is preferably 1 piece / 40 cm square or less. Further, it is desirable that the number of protrusions having a height of 2 μm or more is 5 pieces / 40 cm square or less, more preferably 3 pieces / 40 cm square or less, and even more preferably 1 piece / 40 cm square or less. If the number is larger than this, the filler may straddle between the wirings, resulting in failure of conduction, the failure to break through the film thickness of the photoresist mask, etc., and the automatic inspection system may determine that the inorganic particles are foreign matter and cause a failure. It is not preferable from coming.

  A slurry in which such inorganic particles are dispersed in the same polar solvent as the organic solvent used for the production of polyimide is added to the polyamic acid solution in the polyimide production process, followed by decyclization and desolvation to obtain a polyimide film. Although it is preferable, after adding inorganic particle slurry to an organic solvent before polyamic acid polymerization, a polyimide film is obtained through polyamic acid polymerization and decyclization desolvation, etc. In any process, it is possible to add the inorganic particle slurry.

Specific examples of the inorganic particles used in the present invention include SiO ₂ (silica), TiO ₂ , CaHPO ₄ , Ca ₂ P ₂ O _{7 and the} like. Among them, silica produced by a sol-gel method or a wet pulverization method is preferable in that it is stable in a varnish-like polyamic acid solution and physically stable and does not affect various physical properties of polyimide.

  Furthermore, the fine silica powder is agglomerated by using it as a silica slurry that is uniformly dispersed in a polar solvent such as N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, and n-methylpyrrolidone. It is preferable to prevent this. Since this slurry has a very small particle size, the sedimentation rate is slow and stable. Even if it settles, it can be easily redispersed by re-stirring.

  Although it does not specifically limit about the thickness of the polyimide film used by this invention, Preferably it is 1-225 micrometers, More preferably, it is 5-175 micrometers. When it is too thick, it becomes easy to cause winding slip when it is made into a roll, and when it is too thin, wrinkles and the like are likely to enter.

  The copper layer of the present invention is formed by directly forming a copper layer on one or both sides of the polyimide film as described above, for example, by plating without using an adhesive.

  Specifically, for example, under a vacuum condition on the surface on which copper is to be formed, nickel / chromium is subjected to a base treatment by sputtering, and then copper is sputtered to form a thin copper thin film, and then a copper sulfate bath The copper-clad plate of the present invention can be obtained by laminating a copper layer with electrolytic plating, for example. The copper thickness at this time is preferably 3 to 20 μm, and more preferably 5 to 15 μm.

  In the present invention, since the copper layer is directly formed on the film surface, the protrusions on the film surface cause protrusions on the copper surface. And since the projection on the film surface serves as a nucleus and the projection on the copper surface is formed so as to cover the periphery, the size of the projection on the copper surface is larger than the projection on the film surface from which it originates. Is common. As mentioned above, a copper layer is formed on a film having protrusions of 20 μm or more of 1/40 cm square and protrusions of 2 μm or more in height / 40 cm square as projections on the film surface. Thus, the number of protrusions having a copper surface size of 20 μm or more can be suppressed to 40/10 cm square or less.

  The copper-clad plate of the present invention thus configured has slipperiness by adding inorganic fine particles to generate surface protrusions, and further, an automatic flexible printed circuit board (FPC) or chip-on-film (COF) Since it can be applied to an optical inspection system (AOI), it can be preferably applied to a high-performance flexible printed circuit board using a polyimide film.

  Hereinafter, the present invention will be described more specifically with reference to examples.

  In addition, although the polyimide film used by the Example uses what was formed into a film by the method of the synthesis examples 1-10, it is not limited to these. Moreover, the polyimide film used by the comparative example used what was formed into a film by the synthesis examples 11-14.

  Moreover, each characteristic of the polyimide film obtained by the synthesis example and the Example and the copper-clad board was evaluated by the following method.

(1) Film thickness It measured as follows using the Mitutoyo lightmatic (Series318) thickness meter. That is, 15 points were selected arbitrarily from the entire surface of the film, the thicknesses were measured at these 15 points, and the average was calculated to obtain the thickness.

(2) Linear expansion coefficient A TMA-50 thermomechanical analyzer manufactured by Shimadzu Corporation was used, and measurement was performed under conditions of a measurement temperature range of 50 to 200 ° C and a temperature increase rate of 10 ° C / min. The load was 0.25 N, and the temperature was first raised from 35 ° C. at 10 ° C./min to 300 ° C. Hold at 300 ° C. for 5 minutes, then lower the temperature at 10 ° C./minute to lower the temperature to 35 ° C., hold at 35 ° C. for 30 minutes, then raise the temperature at 10 ° C./minute to raise the temperature to 300 ° C. It was. The data at the time of the second temperature increase from 35 ° C. to 300 ° C. was read, and the linear expansion coefficient was calculated from the average of the portion of 50 to 200 ° C.

(3) Elasticity modulus RTM-250 Tensilon universal testing machine manufactured by A & D was used, and the tensile velocity was measured under the condition of 100 mm / min. Load cell 10Kgf, measurement accuracy ± 0.5% full scale, measure stress-strain curve, slope of straight line of rising part of stress-strain curve (calculated by least square method between 2N to 15N), initial Calculation was performed as follows from the sample length, the sample width, and the sample thickness.
Elastic modulus = (Slope of straight line portion × initial sample length) / (sample width × sample thickness)

(4) Humidity expansion coefficient At 25 ° C, a film was mounted in a TM7000 furnace manufactured by ULVAC, dried air was fed into the furnace and dried for 2 hours, and then the TM7000 furnace was supplied with air from an HC-1 type steam generator. Was humidified to 90% RH, and the coefficient of humidity expansion was determined from the dimensional change during that period. The humidification time was 7 hours. The data from 3RH% to 90RH% was read, and the humidity expansion coefficient was calculated from the average of the portion of 3 to 90RH%.

(5) Water absorption rate It left still in the desiccator of 98% RH atmosphere for 2 days, and evaluated by the weight increase with respect to the weight at the time of drying. Specifically, the film was cut into a 6 cm diameter circle, and the weight (W0) after heat treatment at 200 ° C. for 1 hour was measured as the dry weight, and then allowed to stand in a desiccator under a 98% RH atmosphere for 2 days. The weight (W1) of the water-absorbed film was measured, and the water absorption rate was determined by the following formula.
Water absorption rate = (W1-W0) / WO × 100

(6) Heat shrinkage rate A film of 20 cm × 20 cm was prepared, and the film size (L1) after being left in a room adjusted to 25 ° C. and 60% RH for 2 days was measured, followed by heating at 200 ° C. for 60 minutes. Thereafter, the film size (L2) was measured after being left in a room adjusted to 25 ° C. and 60% RH for 2 days, and evaluated by the following formula calculation.
Heat shrinkage rate = − (L2−L1) / L1 × 100

(7) Friction coefficient (Static friction coefficient)
The films were overlapped and measured based on JIS K-7125 (1999). That is, using a slip coefficient measuring device Slip Tester (manufactured by Technonez Co., Ltd.), overlapping the films, placing a 200 g weight thereon, fixing one of the films, pulling the other at 100 mm / min, The coefficient of friction was measured.

(8) Automatic optical inspection (AOI)
The base film was inspected using SK-75 manufactured by Orbotech. The case where a foreign substance and a fine particle could be distinguished was evaluated as “◯”, while the case where the size of the foreign substance and the fine particle was similar and could not be distinguished from each other was evaluated as a “x” evaluation.

(9) Evaluation of inorganic particles Using a laser diffraction / scattering particle size distribution measuring apparatus LA-910 manufactured by HORIBA, Ltd., a sample dispersed in a polar solvent was measured and analyzed, and the particle size range, average particle size, and particle size were obtained. The occupancy ratio for all particles of 0.15 to 0.60 μm was read.

(10) Number of abnormal protrusions The number of protrusions having a size of 20 μm or more and the number of protrusions having a height of 2 μm or more were counted per 40 cm square area of the film. The size measurement and the height measurement were performed by using a scanning laser microscope “1LM15W” manufactured by Lasertec Co., Ltd., using a Nikon 100 × lens (CF Plan 100 × / 0.95∞ / 0 EPI). It was confirmed by photographing and analyzing the film surface in the “mode”.

(Synthesis Example 1)
Pyromellitic dianhydride (molecular weight 218.12) / 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (molecular weight 294.22) / 4,4′-diaminodiphenyl ether (molecular weight 200.24) / Paraphenylenediamine (molecular weight 108.14) in a molar ratio of 7/3/8/2 was prepared and polymerized in a 18.5 wt% solution in DMAc (N, N-dimethylacetamide) to give 3000 poise Of polyamic acid was obtained. A conversion agent composed of acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. In this mixture, particles having a particle size of 0.01 μm or more and 1.5 μm or less, an average particle size of 0.44 μm, and a particle size of 0.15 to 0.60 μm were 87.3% by volume in all particles. The N, N-dimethylacetamide slurry of silica was added to the varnish-like polyamic acid solution in an amount of 0.40% by weight per resin weight, sufficiently stirred and dispersed, and then rotated by a T-type slit die made of stainless steel at 100 ° C. The gel film was cast on a drum to obtain a self-supporting gel film having a residual volatile component of 55% by weight and a thickness of about 0.30 mm. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 38 μm. The physical properties are shown in Table 1.

(Synthesis Example 2)
Pyromellitic dianhydride (molecular weight 218.12) / 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (molecular weight 294.22) / 4,4′-diaminodiphenyl ether (molecular weight 200.24) / Paraphenylenediamine (molecular weight 108.14) is prepared in a molar ratio of 3/1/3/1, polymerized to a 18.5 wt% solution in DMAc (N, N-dimethylacetamide), and 3000 poise Of polyamic acid was obtained. A conversion agent composed of acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. In this mixture, particles having a particle diameter of 0.01 μm or more and 1.5 μm or less, an average particle diameter of 0.37 μm, and a particle diameter of 0.15 to 0.60 μm are 87.9% by volume in all particles. The N, N-dimethylacetamide slurry of silica was added to the varnish-like polyamic acid solution at 0.35% by weight per resin weight, sufficiently stirred and dispersed, and then rotated by a T-type slit die made of stainless steel at 100 ° C. Casting on a drum, a gel film having a self-supporting property of 55% by weight of residual volatile components and a thickness of about 0.20 mm was obtained. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 25 μm. The physical properties are shown in Table 1.

(Synthesis Example 3)
Pyromellitic dianhydride (molecular weight 218.12) / 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (molecular weight 294.22) / 4,4′-diaminodiphenyl ether (molecular weight 200.24) / Paraphenylenediamine (molecular weight 108.14) is prepared in a molar ratio of 7/3/7/3, polymerized in a 18.5% by weight solution in DMAc (N, N-dimethylacetamide), 3000 poise Of polyamic acid was obtained. A conversion agent composed of acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. In this mixture, the particle size is 0.01 μm or more and 1.5 μm or less, and the average particle size is 0.45 μm and the particle size is 0.15 to 0.60 μm. The N, N-dimethylacetamide slurry of silica was added to the varnish-like polyamic acid solution at 0.30% by weight per resin weight, sufficiently stirred and dispersed, and then rotated by a T-type slit die made of stainless steel at 100 ° C. The gel film was cast on a drum to obtain a self-supporting gel film having a residual volatile component of 55% by weight and a thickness of about 0.30 mm. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 38 μm. The physical properties are shown in Table 1.

(Synthesis Example 4)
Pyromellitic dianhydride (molecular weight 218.12) / 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (molecular weight 294.22) / 4,4′-diaminodiphenyl ether (molecular weight 200.24) / Paraphenylenediamine (molecular weight 108.14) is prepared in a molar ratio of 4/1/3/2, polymerized to a 18.5 wt% solution in DMAc (N, N-dimethylacetamide), and 3000 poise Of polyamic acid was obtained. A conversion agent composed of acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. In this mixture, particles having a particle size of 0.01 μm or more and 1.5 μm or less, an average particle size of 0.47 μm, and a particle size of 0.15 to 0.60 μm were 87.8% by volume in all particles. The N, N-dimethylacetamide slurry of silica was added to the varnish-like polyamic acid solution at 0.50% by weight per resin weight, sufficiently stirred and dispersed, and then rotated by a T-type slit die made of stainless steel at 100 ° C. The gel film was cast on a drum to obtain a self-supporting gel film having a residual volatile component of 55% by weight and a thickness of about 0.30 mm. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 38 μm. The physical properties are shown in Table 1.

(Synthesis Example 5)
Prepare pyromellitic dianhydride (molecular weight 218.12) / 4,4'-diaminodiphenyl ether (molecular weight 200.24) / paraphenylenediamine (molecular weight 108.14) at a molar ratio of 4/3/1. Polymerization was carried out at a solution concentration of 18.5 wt% in DMAc (N, N-dimethylacetamide) to obtain 3000 poise polyamic acid. A conversion agent composed of acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. In this mixture, particles having a particle size of 0.01 μm or more and 1.5 μm or less, an average particle size of 0.40 μm, and a particle size of 0.15 to 0.60 μm are 88.2% by volume in all particles. The N, N-dimethylacetamide slurry of silica was added to the varnish-like polyamic acid solution in an amount of 0.40% by weight per resin weight, sufficiently stirred and dispersed, and then rotated by a T-type slit die made of stainless steel at 100 ° C. The gel film was cast on a drum to obtain a self-supporting gel film having a residual volatile component of 55% by weight and a thickness of about 0.30 mm. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 38 μm. The physical properties are shown in Table 1.

(Synthesis Example 6)
Prepare pyromellitic dianhydride (molecular weight 218.12) / 4,4'-diaminodiphenyl ether (molecular weight 200.24) / paraphenylenediamine (molecular weight 108.14) at a molar ratio of 10/7/3. Polymerization was carried out at a solution concentration of 18.5 wt% in DMAc (N, N-dimethylacetamide) to obtain 3000 poise polyamic acid. A conversion agent composed of acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. In this mixture, the particle size is 0.01 μm or more and 1.5 μm or less, and the average particle size is 0.50 μm and the particle size is 0.15 to 0.60 μm. The N, N-dimethylacetamide slurry of silica was added to the varnish-like polyamic acid solution in an amount of 0.45% by weight per resin weight, sufficiently stirred and dispersed, and then rotated by a T-type slit die made of stainless steel at 100 ° C. Casting on a drum, a gel film having a self-supporting property of 55% by weight of residual volatile components and a thickness of about 0.20 mm was obtained. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 25 μm. The physical properties are shown in Table 2.

(Synthesis Example 7)
Prepare pyromellitic dianhydride (molecular weight 218.12) / 4,4'-diaminodiphenyl ether (molecular weight 200.24) / paraphenylenediamine (molecular weight 108.14) in a molar ratio of 5/4/1. Polymerization was carried out at a solution concentration of 18.5 wt% in DMAc (N, N-dimethylacetamide) to obtain 3000 poise polyamic acid. A conversion agent consisting of acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. In this mixture, particles having a particle size of 0.01 μm or more and 1.5 μm or less, an average particle size of 0.45 μm, and a particle size of 0.15 to 0.60 μm are 88.5% by volume in all particles. The N, N-dimethylacetamide slurry of silica was added to the varnish-like polyamic acid solution at 0.35% by weight per resin weight, sufficiently stirred and dispersed, and then rotated by a T-type slit die made of stainless steel at 100 ° C. The gel film was cast on a drum to obtain a self-supporting gel film having a residual volatile component of 55% by weight and a thickness of about 0.30 mm. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 38 μm. The physical properties are shown in Table 2.

(Synthesis Example 8)
Pyromellitic dianhydride (molecular weight 218.12) / 3,4′-diaminodiphenyl ether (molecular weight 200.24) / 4,4′-diaminodiphenyl ether (molecular weight 200.24) in a molar ratio of 5/2/3 The polymer was prepared at a ratio of 18.5 wt% in DMAc (N, N-dimethylacetamide) and polymerized to obtain 3000 poise polyamic acid. A conversion agent consisting of acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. In this mixture, particles having a particle size of 0.01 μm or more and 1.5 μm or less, an average particle size of 0.38 μm, and a particle size of 0.15 to 0.60 μm are 88.2% by volume in all particles. The N, N-dimethylacetamide slurry of silica was added to the varnish-like polyamic acid solution at 0.30% by weight per resin weight, sufficiently stirred and dispersed, and then rotated by a T-type slit die made of stainless steel at 100 ° C. The gel film was cast on a drum to obtain a self-supporting gel film having a residual volatile component of 55% by weight and a thickness of about 0.30 mm. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 38 μm. The physical properties are shown in Table 2.

(Synthesis Example 9)
Pyromellitic dianhydride (molecular weight 218.12) / 3,4′-diaminodiphenyl ether (molecular weight 200.24) / 4,4′-diaminodiphenyl ether (molecular weight 200.24) in a molar ratio of 2/1/1 The polymer was prepared at a ratio of 18.5 wt% in DMAc (N, N-dimethylacetamide) and polymerized to obtain 3000 poise polyamic acid. A conversion agent composed of acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. In this mixture, the particle size is 0.01 μm or more and 1.5 μm or less, and the average particle size is 0.40 μm and the particle size is 0.15 to 0.60 μm. The N, N-dimethylacetamide slurry of silica was added to the varnish-like polyamic acid solution at 0.35% by weight per resin weight, sufficiently stirred and dispersed, and then rotated by a T-type slit die made of stainless steel at 100 ° C. The gel film was cast on a drum to obtain a self-supporting gel film having a residual volatile component of 55% by weight and a thickness of about 0.30 mm. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 38 μm. The physical properties are shown in Table 2.

(Synthesis Example 10)
Pyromellitic dianhydride (molecular weight 218.12) / 3,4′-diaminodiphenyl ether (molecular weight 200.24) / 4,4′-diaminodiphenyl ether (molecular weight 200.24) in a molar ratio of 100/45/55 The polymer was prepared at a ratio of 18.5 wt% in DMAc (N, N-dimethylacetamide) and polymerized to obtain 3000 poise polyamic acid. A conversion agent composed of acetic anhydride (molecular weight 102.09) and isoquinoline was mixed and stirred at a ratio of 50% by weight to the polyamic acid solution. At this time, it prepared so that acetic anhydride and isoquinoline might be 2.0 and 0.4 molar equivalent with respect to the amic acid group of a polyamic acid, respectively. In this mixture, the particle diameter is 0.01 μm or more and 1.5 μm or less, and the average particle diameter is 0.50 μm and the particle diameter is 0.15 to 0.60 μm. The N, N-dimethylacetamide slurry of silica was added to the varnish-like polyamic acid solution at 0.38% by weight per resin weight, sufficiently stirred and dispersed, and then rotated by a T-type slit die made of stainless steel at 100 ° C. Casting on a drum, a gel film having a self-supporting property of 55% by weight of residual volatile components and a thickness of about 0.20 mm was obtained. This gel film was peeled off from the drum, and both ends thereof were gripped and treated in a heating furnace at 200 ° C. for 30 seconds, 350 ° C. for 30 seconds, and 550 ° C. for 30 seconds to obtain a polyimide film having a thickness of 25 μm. The physical properties are shown in Table 2.

(Synthesis Example 11)
In Synthesis Example 1, a polyimide film was obtained in the same manner as in Synthesis Example 1 except that silica was not added. Table 3 shows the physical properties.

(Synthesis Example 12)
The silica used in Synthesis Example 1 has a particle size of 0.1 μm or more and 4.5 μm or less, particles having an average particle size of 1.1 μm and a particle size of 0.15 to 0.60 μm in all particles. Except for changing to 27.3 vol% calcium hydrogen phosphate and adding 0.2 wt% of N, N-dimethylacetamide slurry to the varnish-like polyamic acid solution per resin weight, the same as in Synthesis Example 1 A polyimide film was obtained by this method. Table 3 shows the physical properties.

(Synthesis Example 13)
The silica used in Synthesis Example 1 has a particle diameter of 0.01 μm or more and 0.3 μm or less, particles having an average particle diameter of 0.08 μm and a particle diameter of 0.15 to 0.60 μm in all particles. Polyimide was prepared in the same manner as in Synthesis Example 1 except that the silica was changed to 31.4% by volume and N, N-dimethylacetamide slurry was added to the varnish-like polyamic acid solution at 0.35% by weight per resin weight. A film was obtained. Table 3 shows the physical properties.

(Synthesis Example 14)
The silica used in Synthesis Example 1 has a particle diameter of 0.01 μm or more and 1.5 μm or less, particles having an average particle diameter of 0.40 μm and a particle diameter of 0.15 to 0.60 μm in all particles. Polyimide was prepared in the same manner as in Synthesis Example 1 except that 72.6% by volume of silica was used and N, N-dimethylacetamide slurry was added to the varnish-like polyamic acid solution at 0.35% by weight per resin weight. A film was obtained. Table 3 shows the physical properties.

Example 1
The polyimide film formed in Synthesis Example 1 was used and the vacuum chamber was brought to an ultimate pressure of 1 × 10 ⁻³ Pa, and then nickel / chromium = 95/5 by DC magnetron sputtering at an argon gas pressure of 1 × 10 ⁻¹ Pa. (Weight ratio) nichrome alloy was sputtered on one side so as to have a thickness of 5 nm, and copper was further sputtered so as to have a thickness of 50 nm. Next, a copper layer having a thickness of 6 μm was laminated by electrolytic plating using a copper sulfate bath under the condition of a current density of ² A / dm ² to prepare a single-sided flexible copper-clad plate. The composition of the copper sulfate bath was a solution in which an appropriate amount of additives was added to copper sulfate pentahydrate 80 g / liter, sulfuric acid 200 g / liter, and hydrochloric acid 50 mg / liter.

  The static friction coefficient, AOI, the number of abnormal protrusions of the polyimide film portion of the obtained copper-clad plate, and the number of abnormal protrusions of the copper side portion were measured. The results are shown in Table 4. Since the coefficient of static friction is low, transportability is good, there are few abnormal protrusions, and the interruption of AOI inspection due to erroneous detection is reduced, which is suitable for a copper-clad plate for forming fine wiring.

(Example 2)
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 2 was used. The static friction coefficient, AOI, the number of abnormal protrusions of the polyimide film portion of the obtained copper-clad plate, and the number of abnormal protrusions of the copper side portion were measured. The results are shown in Table 4. Since the coefficient of static friction is low, transportability is good, there are few abnormal protrusions, and the interruption of AOI inspection due to erroneous detection is reduced, which is suitable for a copper-clad plate for forming fine wiring.

(Example 3)
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 3 was used. The static friction coefficient, AOI, the number of abnormal protrusions of the polyimide film portion of the obtained copper-clad plate, and the number of abnormal protrusions of the copper side portion were measured. The results are shown in Table 4. Since the coefficient of static friction is low, transportability is good, there are few abnormal protrusions, and the interruption of AOI inspection due to erroneous detection is reduced, which is suitable for a copper-clad plate for forming fine wiring.

Example 4
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 4 was used. The static friction coefficient, AOI, the number of abnormal protrusions of the polyimide film portion of the obtained copper-clad plate, and the number of abnormal protrusions of the copper side portion were measured. The results are shown in Table 4. Since the coefficient of static friction is low, transportability is good, there are few abnormal protrusions, and the interruption of AOI inspection due to erroneous detection is reduced, which is suitable for a copper-clad plate for forming fine wiring.

(Example 5)
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 5 was used. The static friction coefficient, AOI, the number of abnormal projections and the number of abnormal projections on the copper side portion of the polyimide film portion of the obtained copper-clad plate were measured. The results are shown in Table 4. Since the coefficient of static friction is low, transportability is good, there are few abnormal protrusions, and the interruption of AOI inspection due to erroneous detection is reduced, which is suitable for a copper-clad plate for forming fine wiring.

(Example 6)
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 6 was used. The static friction coefficient, AOI, the number of abnormal protrusions of the polyimide film portion of the obtained copper-clad plate, and the number of abnormal protrusions of the copper side portion were measured. The results are shown in Table 4. Since the coefficient of static friction is low, transportability is good, there are few abnormal protrusions, and the interruption of AOI inspection due to erroneous detection is reduced, which is suitable for a copper-clad plate for forming fine wiring.

(Example 7)
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 7 was used. The static friction coefficient, AOI, the number of abnormal protrusions of the polyimide film portion of the obtained copper-clad plate, and the number of abnormal protrusions of the copper side portion were measured. The results are shown in Table 4. Since the coefficient of static friction is low, transportability is good, there are few abnormal protrusions, and the interruption of AOI inspection due to erroneous detection is reduced, which is suitable for a copper-clad plate for forming fine wiring.

(Example 8)
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 8 was used. The static friction coefficient, AOI, the number of abnormal protrusions of the polyimide film portion of the obtained copper-clad plate, and the number of abnormal protrusions of the copper side portion were measured. The results are shown in Table 4. Since the coefficient of static friction is low, transportability is good, there are few abnormal protrusions, and the interruption of AOI inspection due to erroneous detection is reduced, which is suitable for a copper-clad plate for forming fine wiring.

Example 9
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 9 was used. The static friction coefficient, AOI, the number of abnormal protrusions of the polyimide film portion of the obtained copper-clad plate, and the number of abnormal protrusions of the copper side portion were measured. The results are shown in Table 4. Since the coefficient of static friction is low, transportability is good, there are few abnormal protrusions, and the interruption of AOI inspection due to erroneous detection is reduced, which is suitable for a copper-clad plate for forming fine wiring.

(Example 10)
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 10 was used. The static friction coefficient, AOI, the number of abnormal projections and the number of abnormal projections on the copper side portion of the polyimide film portion of the obtained copper-clad plate were measured. The results are shown in Table 4. Since the coefficient of static friction is low, transportability is good, there are few abnormal protrusions, and the interruption of AOI inspection due to erroneous detection is reduced, which is suitable for a copper-clad plate for forming fine wiring.

(Comparative Example 1)
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 11 was used. The static friction coefficient, AOI, the number of abnormal protrusions of the polyimide film portion of the obtained copper-clad plate, and the number of abnormal protrusions of the copper side portion were measured. The results are shown in Table 4. Since the coefficient of static friction is high and the slipperiness is poor, it causes problems in transporting the copper-clad plate, so it cannot be applied to a copper-clad plate.

(Comparative Example 2)
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 12 was used. The static friction coefficient, AOI, the number of abnormal protrusions of the polyimide film portion of the obtained copper-clad plate, and the number of abnormal protrusions of the copper side portion were measured. The results are shown in Table 4. The polyimide film part of the obtained copper-clad plate has so many abnormal protrusions that the AOI inspection must be interrupted frequently because the abnormal protrusions are mistakenly detected as foreign objects in the AOI inspection, and the number of abnormal protrusions on the copper side is also large. It could not be applied as a copper-clad plate for forming fine wiring.

(Comparative Example 3)
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 13 was used. The static friction coefficient, AOI, the number of abnormal protrusions of the polyimide film portion of the obtained copper-clad plate, and the number of abnormal protrusions of the copper side portion were measured. The results are shown in Table 4. Since the coefficient of static friction is high and the slipperiness is poor, it causes problems in transporting the copper-clad plate, so it cannot be applied to a copper-clad plate.

(Comparative Example 4)
A copper-clad plate was formed in the same manner as in Example 1 except that the polyimide film formed in Synthesis Example 14 was used. In this example, since the occupation ratio of the particle diameter of 0.9 to 1.3 μm occupied 22.0% by volume, the number of abnormal protrusions increased due to this. The static friction coefficient, AOI, the number of abnormal protrusions of the polyimide film portion of the obtained copper-clad plate, and the number of abnormal protrusions of the copper side portion were measured. The polyimide film part of the copper-clad board has many abnormal protrusions that the AOI inspection must be interrupted frequently because the abnormal protrusions are erroneously detected as foreign objects in the AOI inspection, and the number of abnormal protrusions on the copper side is large and fine wiring is formed. It was not applicable as a copper-clad plate for use.

  The copper-clad plate of the present invention is easy to slip by adding inorganic fine particles to generate surface protrusions. Furthermore, an automatic optical inspection system for a flexible printed circuit board (FPC) or chip-on-film (COF) ( Since it can be applied to AOI), it can be preferably applied to a high-performance flexible printed circuit board using a polyimide film.

Claims (4)

In the polyimide film, particles having a particle diameter of 0.01 to 1.5 μm, an average particle diameter of 0.05 to 0.7 μm, and particles having a particle diameter of 0.15 to 0.60 μm are 80% by volume or more in all particles. A polyimide film in which inorganic particles having a particle size distribution occupying a ratio of 0.1 to 0.9% by weight per film resin weight are dispersed and contained, and an adhesive is applied to one or both sides of this polyimide film. A copper-clad board, wherein a copper layer is directly formed without any interposition. 2. The copper-clad plate according to claim 1, wherein protrusions due to the inorganic particles are present on the surface of the polyimide film, and the number of protrusions having a size of 20 μm or more is 1/40 cm square or less. 3. The copper-clad plate according to claim 1, wherein the number of protrusions having a height of 2 μm or more present on the surface of the polyimide film is 5/40 cm square or less. 4. The number of protrusions having a size of 20 μm or more present on the surface of the copper layer formed on the surface of the polyimide film is 40/10 cm square or less, according to claim 1. Copper-clad board.