JPH0457389B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] This invention relates to a method for producing a polyimide-metal foil composite film. [Background Art] A composite film formed by laminating polyimide and metal foil is useful as an electric circuit board. Methods for manufacturing this composite film include a method of bonding a polyimide film to a metal foil via an adhesive, a method of heat-sealing a polyimide film onto a metal foil,
There is a method in which a solution of a polyimide precursor in an organic polar solvent is applied onto a metal foil, dried, and then imidized to form a polyimide film. Among these manufacturing methods, methods and have the disadvantage of complicating the process because the polyimide precursor must be made into a film in advance. It has the problem of occurring. On the other hand, the manufacturing method does not require film formation in advance like the methods of and, so the process can be simplified and a thin composite film can be formed, and there are no problems caused by adhesives as in the methods of It has the following advantages. However, in this method, the polyimide film is formed directly on the metal foil and no adhesive is used, so depending on the composition of the polyimide precursor, the adhesive force between the produced polyimide film and the metal foil may be insufficient, resulting in the polyimide film being formed directly on the metal foil. - It is expected that during circuit pattern formation or soldering on a metal foil composite film, floating and peeling phenomena of the conductor may occur, causing defects. Also,
In this method, the coating film shrinks when it is heated and cooled during drying or imidization, so
Due to the metal foil that is difficult to follow this shrinkage, the obtained composite film curls, making it unsuitable for circuit processing and having poor handling properties during processing. [Object of the Invention] The present invention is directed to producing a polyimide-metal foil composite film in which a polyimide film and a metal foil are firmly bonded without substantially curling, without forming the polyimide into a film in advance. The purpose is to provide a method to do so. [Disclosure of the Invention] In order to achieve the above object, the method for producing a polyimide-metal foil composite film of the present invention includes a method for producing a polyimide-metal foil composite film of the present invention. A step of preparing an organic polar solvent solution of a polyimide precursor obtained by reacting a compound with a tetracarboxylic acid compound whose main component is the following component (C), The method includes a step of coating the polyimide precursor onto a foil, and a step of heating the metal foil coated with the organic polar solvent solution of the polyimide precursor in a fixed state to form a polyimide thin film on the foil surface of the metal foil. (A) p-phenylenediamine (B) General formula [In the formula, R ₁ is a methylene group, a phenylene group or a substituted phenylene group, R ₂ is a methylene group, a phenyl group or a substituted phenyl group, X is an oxygen atom,
phenylene group or substituted phenylene group, n is
When R ₁ is a phenylene group or a substituted phenylene group, it is an integer of 1, and when it is a methylene group, it is an integer of 3 or 4. ] Silicon-based diamine represented by. (C) At least one of 3,3',4,4'-biphenyltetracarboxylic dianhydride and its derivatives. That is, the method of the present invention uses a diamino compound containing 0.1 to 10 mol% of the silicon diamine described above as a diamino compound for forming a polyimide film, and contains silicon derived from the silicon diamine in the polyimide film formed. Because of the introduction of atoms, the resulting polyimide film becomes firmly bonded to the metal foil. Furthermore, since the specific diamino compounds and tetracarboxylic acid compounds mentioned above are used as the diamino compounds and tetracarboxylic acid compounds for forming the polyimide film, the resulting polyimide film is similar to metal foil made of copper, aluminum, etc. They have similar coefficients of linear expansion. Moreover, when forming the above-mentioned polyimide film on this metal foil, the heat treatment for polyimidization is performed with the metal foil fixed, so that the stress generated in the polyimide film is relaxed, and this effect and Coupled with the linear expansion coefficient approximation effect, the polyimide-metal foil composite film is prevented from curling in both the length direction and the width direction. The diamino compound for forming the polyimide precursor (polyimide film) in the method of this invention contains 80 to 99.9 mol% of p-phenylenediamine and 0.1 to 10 mol% of silicone diamine represented by the above general formula, with the remainder contains other diamines. If the proportion of p-phenylenediamine is too small, the difference in linear expansion coefficient between the metal foil made of copper, aluminum, etc. and the polyimide film becomes large, which is not preferable. Further, the proportion of the silicon diamine needs to be set within the range of 0.1 to 10 mol% as described above, and the preferable range is 2 to 7 mol%. That is, if the silicon-based diamine is less than 0.1 mol%, the effect of improving bonding or adhesion to metal foil cannot be obtained, and conversely, if it exceeds 10 mol%,
This is because the properties of the polyimide film, such as its moisture absorption rate and heat resistance, may be reduced, or its coefficient of linear expansion may be increased. Specific examples of such silicon-based diamines are as follows. Other diamines mentioned above include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone,
m-phenylenediamine, 4,4'-diaminodiphenylpropane, 1,5-diaminonaphthalene,
2,6-diaminonaphthalene, 4,4'-diaminodiphenyl sulfide, 4,4'-di(m-aminophenoxy) diphenyl sulfone, 3,3'-di(m-aminophenoxy) diphenyl sulfone,
Examples include 4,4'-di(m-aminophenoxy)diphenylpropane, 3,3'-dimethyl-4,4'-diaminophenyl, and one or more of these may be used as appropriate. . Moreover, about several mol% of diaminosiloxane may be used. The tetracarboxylic acid compound for forming the polyimide precursor in this invention is mainly composed of 3,3',4,4'-biphenyltetracarboxylic dianhydride or its derivatives such as acid halides, diesters, and monoesters. It is something to do. Here, the term "main component" includes the case where the whole consists of only the main component. However, it usually contains 70 mol% or more of this dianhydride or its derivatives and 30% or less of other aromatic tetracarboxylic dianhydrides or their derivatives such as acid halides, diesters, and monoesters. used. 3,
If the proportion of 3',4,4'-biphenyltetracarboxylic dianhydride or its derivatives is too small, the difference in linear expansion coefficient between the metal foil made of copper, aluminum, etc. and the polyimide film will become large, or the film will deteriorate. This is not preferable because it causes problems such as an extreme decrease in strength. Other aromatic tetracarboxylic dianhydrides or derivatives thereof include pyromellitic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,3,6, Examples include acid dianhydrides such as 7-naphthalenetetracarboxylic dianhydride or derivatives thereof, and one of these
A species or two or more species may be used as appropriate. Among these, pyromellitic dianhydride or its derivatives, and 3,3',4,4'-benzophenonetetracarboxylic dianhydride or its derivatives are particularly preferred. The reason is that even if these tetracarboxylic acid compounds are reacted alone with the specific diamino compound, it is difficult to produce a polyimide film with excellent film strength. This is because it contributes to achieving the purpose of this invention, which is prevention. In order to obtain a polyimide precursor by reacting the above-mentioned diamino compound and tetracarboxylic acid compound, approximately equimolar amounts of both these compounds are reacted in an organic polar solvent, usually at 0 to 90°C for 1 to 24 hours, and polyamic acid, etc. A polyimide precursor is prepared. As the organic polar solvent, N-methyl-2
-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, dimethylphosphoamide, m-cresol, p-cresol, p-chlorophenol and the like. Further, a portion of xylene, toluene, hexane, naphtha, etc. may be mixed therein. The organic polar solvent solution of the polyimide precursor thus obtained has a logarithmic viscosity (N-methyl-
(measured below 30°C at a concentration of 0.5 g/100 ml in 2-pyrrolidone) is preferably in the range 04 to 7.0.
More preferably, it is within the range of 1.5 to 3.0. If this value is too small, the resulting polyimide film will have a low mechanical strength, which is not preferable. Moreover, if this value is too large, the coating workability on metal foil will be lowered, which is not preferable. In the present invention, a polyimide-metal foil composite film is manufactured, for example, in the following manner using the organic polar solvent solution of the polyimide precursor obtained as described above. That is, first, the organic polar solvent solution of the polyimide precursor described above is heated to a temperature of 80°C or less to lower the viscosity, and in that state, the thickness is 1 to 1.
500 μm, preferably 10-100 μm, particularly preferred
Casting is applied onto a metal foil having a thickness of 20 to 50 μm using an appropriate means such as an applicator. In this case, if the thickness of the metal foil is less than 1 μm, the effect of preventing curling will be reduced and problems may occur in the application, whereas if it exceeds 500 μm, the composite film will lack flexibility and It becomes less suitable for applications such as circuit boards. Therefore, the metal foil used is
Preferably, the thickness is within the range of 1 to 500 μm. As for the type of metal foil, copper foil, aluminum foil or stainless steel foil is preferable, and in addition, silver, iron, an alloy of nickel and chromium, etc. having the above-mentioned thickness, etc.
Materials made of various materials can be used. The length of these metal foils when applying the polyimide precursor solution is not particularly limited. However, in practical terms, the width is about 20 to 200 cm. Of course, it is possible to deviate from the above range. Furthermore, it goes without saying that the composite film obtained using the above-mentioned wide metal foil may be cut into a predetermined width in the final step for use. Note that the organic polar solvent solution of the polyimide precursor obtained as described above may be further diluted with an organic polar solvent as necessary. As the organic polar solvent for dilution in this case, those used during the polymerization reaction of each polyimide precursor can be used.
Also, the concentration of polyimide precursor in the above solution is 10
It is preferable to set it to about 20% by weight. If this concentration is too low, the surface of the polyimide film is likely to become rough, while if it is too high, the viscosity will increase and the coating workability will be impaired. From the viewpoint of coating workability, the viscosity of this solution is generally preferably 5000 poise or less, which is the viscosity during heating coating. Next, after applying the solution, the metal foil is heat-treated in a fixed state. This heat treatment is usually
After removing the solvent by heating and drying at 100 to 230℃ for about 30 minutes to 2 hours, the temperature is further increased to a final temperature of 230 to 600℃.
℃ for 1 minute to 6 hours, preferably at a temperature near the glass transition temperature of the polyimide to be formed, i.e., 250 to 350℃, for 10 minutes to 6 hours to complete the imidization reaction. At the same time, the stress generated in the coating film during the above-mentioned solvent removal and imidization is alleviated. Note that if the above heat treatment is performed at a temperature below 230°C, stress relaxation will be insufficient and the resulting composite film will tend to curl. On the other hand, if it is carried out at a temperature exceeding 600°C, the polyimide will decompose, which is not preferable. In order to prevent such decomposition of polyimide, even if the heating temperature is 600°C or lower, the heating time is preferably less than 10 minutes at a temperature higher than 350°C. Such heat treatment is performed while the metal foil coated with the polyimide precursor solution is fixed as described above. This fixing method includes fixing the metal foil on a glass plate etc. in a flat plate using polyimide tape, or fixing the metal foil by wrapping both lengthwise ends of the metal foil around a roll. Depending on the length and size of the material, various methods can be used to substantially fix the material in both the width and length directions.After the heat treatment is performed in this manner, the material is cooled to room temperature. The above-mentioned fixation may be released at any time after the high-temperature heat treatment, but it is preferable to release the fixation after cooling to room temperature. Through this series of steps, a stress-relaxed polyimide film is formed on the metal foil. In this case, it is preferable to set the thickness of the polyimide film to 5 to 200 μm. More preferably 10-100μ
m, most preferably 10 to 50 μm.
If the thickness is less than 5 μm, the film properties will deteriorate, and if it exceeds 200 μm, the curl prevention effect will be reduced and the film will lack flexibility, making it unsuitable for applications such as electrical circuit boards. Therefore, the thickness of the polyimide film is 5~
It is preferable to set it to 200 μm. The above polyimide membrane generally has an average linear expansion coefficient in the range of 1.2 × 10 ^-5 to 2.9 × 10 ^-5 1/℃ at 50 to 250 °C, but in some cases, the average linear expansion coefficient is even smaller than the above value. It is also possible to make it a coefficient. On the other hand, the average linear expansion coefficient of metal foil in the same temperature range as above, for example, metal foil with a thickness of 1 to 500 μm, is in the range of 1.5 × 10 ^-5 to 1.7 × 10 ^-5 1/℃ for copper foil. , and 2.4×10 ^-5 ~ for aluminum foil
It is in the range of 2.6×1/℃. As described above, in this invention, by appropriately setting the polymer composition of the polyimide film within the above-mentioned specific range and setting the thickness of the polyimide film and the metal foil within the above-mentioned range, the average line between the polyimide film and the metal foil can be adjusted. It has the characteristic that the difference in expansion coefficient can be suppressed to within 0.3×10 ^-5 1/°C. In addition, in this specification, the linear expansion coefficient is
If the length of a material of length l at temperature T changes by Δl when the temperature changes by 1°C, then Δl/
1, and the average coefficient of linear expansion is the average value of the coefficients of linear expansion in a certain temperature range. The linear expansion coefficient was measured using a composite film with a length of 2.5 mm and a width of 3 mm.
A test piece cut into mm pieces was fixed with one lengthwise end facing upward, and the temperature was increased at 10°C/min in a nitrogen gas atmosphere with a load of 15g/ ^mm2 applied to the lower end with a distance between chucks of 10mm. This is done by giving a temperature change at , and finding the above-mentioned Δl/l at this time. The polyimide-metal foil composite film obtained as described above has a radius of curvature of 25 cm or more in both the width direction and the length direction, and is substantially curl-free. That is, the above-mentioned composite film is excellent in that it is substantially curl-free and has a radius of curvature of usually 50 cm or more, preferably ∞. Moreover, the above composite film has excellent heat resistance, chemical resistance, durability, and flexibility, and also has excellent bonding conditions between the polyimide film and metal foil, so it can be used for printed wiring boards, flexible printed wiring boards, and multilayer wiring boards. , suitable for use as diaphragms, etc. Note that the radius of curvature mentioned above refers to the radius of curvature as shown in the drawing.
A test piece of a composite film 3 made of a metal foil 1 and a polyimide film 2 is cut into 10 cm square pieces with a length of 10 cm and a width of 10 cm.The curve of curvature when this test piece is curled in the width direction (not in the length direction) is as follows. The degree is expressed by the radius r from the center P. This radius of curvature r is defined as the length in the width direction (or length direction) in the curled state is a, and the perpendicular line N is drawn from the center P to the horizontal line M that connects both ends in the width direction (or length direction). If h is the length from the intersection R to the center of the film on the extension of the perpendicular line N, then when h≧r, by actually measuring this r, or when h<r
In this case, for convenience, the above a value and h value can be actually measured and calculated using the following formula. r ² = (r-h) ² + (1/2a) ² r ² = r ² -2rh+h ² +1/4a ² 2rh=h ² +1/4a ² r=1/2h+1/8・a2/h As above The polyimide-metal foil composite film obtained by
Due to the small value of r = 25 cm or more, preferably ∞, there is substantially no curl. Also, this composite film has 50
It has the advantage of virtually no curling after cooling even when subjected to processing that applies heat up to 270°C, and in this respect, it has excellent handling properties and dimensional stability when applied to the various applications listed above. It also has excellent characteristics. In the above explanation, the metal foil is coated with a polyimide precursor solution and then fixed and heat-treated. Needless to say, it is okay. [Effects of the Invention] As described above, the method for producing a polyimide-metal foil composite film of the present invention uses a diamino compound containing p-phenylenediamine as a main component and a diamino compound containing p-phenylenediamine as a main component as a diamino compound and a tetracarboxylic acid compound for forming a polyimide film. By using an aromatic tetracarboxylic acid compound whose main component is 3,3',4,4'-biphenyltetracarboxylic dianhydride or a derivative thereof, it is possible to coat a metal foil almost similar to that of the metal foil. A polyimide film having a coefficient of linear expansion can be formed. Moreover, since the metal foil is kept in a fixed state when the polyimide film is heated and formed, stress generated in the polyimide film is alleviated. Due to these synergistic effects, the resulting polyimide-metal foil composite film is free from curling in both the length and width directions. Moreover, in this invention, in order to make the diamino compound contain 0.1 to 10 mol% of silicone diamine represented by the general formula, silicon atoms derived from the silicone diamine are introduced into the resulting polyimide film. As a result, the produced polyimide film is firmly bonded to the metal foil. As a result, during the formation of a circuit pattern on a polyimide-metal foil composite film, floating and peeling phenomena of the conductor do not occur, and the occurrence of defects caused by these phenomena is significantly reduced. The composite film obtained by the method of the present invention has the polyimide film and the metal foil firmly bonded together as described above, and substantially does not curl, so it is suitable for producing electrical circuit boards. It has the advantage that it can be used as a substrate without any problems and is easy to handle during circuit processing. Furthermore, the resulting electric circuit board has the characteristic that it does not easily curl due to temperature changes, and in this respect it has excellent dimensional stability. Specific examples of the use of this composite film include applications for solar cell substrates, hybrid IC substrates, solar water heater heat collecting plates, etc. that are used under severe temperature change conditions. Next, examples will be described together with comparative examples. The radius of curvature and average coefficient of linear expansion below were measured or calculated using the method described above by cutting the composite film produced in each example and comparative example to the size of each test piece. . However, the above radius of curvature is a value measured in both the length direction and the width direction (length and width) of a 10 cm square, meaning that both values are substantially the same. Example 1 P-phenylenediamine in a 500ml flask
10.26 g (0.095 mol), 1.24 g (0.005 mol) of bis(3-aminopropyl)tetramethyldisiloxane represented by the above structural formula (a), and N-methyl-2-pyrrolidone (hereinafter abbreviated as "NMP")
210g of diamine was added and mixed to dissolve the diamine.
Next, while stirring this system, 3,3',4,4'-
Biphenyltetracarboxylic dianhydride 29.4g
(0.1 mol) was added gradually. During this time, the reaction system was cooled with ice water so that the temperature did not exceed 30°C.
Thereafter, the mixture was stirred for 2 hours to obtain an NMP solution of polyamic acid having a concentration of 16.3% by weight (hereinafter abbreviated as "%").
Logarithmic viscosity of this polyamic acid (0.5g/in NMP)
(measured at 30°C at a concentration of 100ml) was 1.83.
Also, the viscosity of this NMP solution is 3510 poise (30
℃). This NMP solution of polyamic acid was heated in advance to lower the viscosity to 1000 poise or less, and then
It was cast using an applicator onto a 35 μm thick copper foil (dimensions are the same as the glass plate above) whose entire circumference was fixed with polyimide film on a 20 cm wide glass plate.
Heat at 150℃ for 30 minutes, 200℃ for 60 minutes, and further heat at 280℃.
It was heated for 2 hours. Thereafter, it was cooled to room temperature, and the fixation of the copper foil was released to obtain a polyimide-metal foil composite film. The resulting polyimide-copper foil composite film had a polyimide coating thickness of 25 μm, a radius of curvature of 75 cm, and was substantially curl-free. In addition, the 90° peel strength between the polyimide film and the copper foil in this composite film was 2.42 Kg/10 mm under normal conditions, and the 90° peel strength after being immersed in a 260°C solder bath for 30 seconds was 2.35 Kg/10 mm. . When the linear expansion coefficient of the polyimide membrane in this composite film was measured using a thermomechanical analyzer (hereinafter abbreviated as "TMA"), the average linear expansion coefficient between 50 and 250°C was 1.66×10 ^-5 1/°C, which was the same. Average linear expansion coefficient of copper foil in temperature range (1.60×10 ^-5 1/℃)
It was almost equal to Comparative Example 1 In place of p-phenylenediamine in Example 1, 4,4'-diaminodiphenyl ether 20.0
g (0.1 mol) was used. Other than that, the procedure was the same as in Example 1 to obtain an NMP solution of polyamic acid with a concentration of 19.0%. Logarithmic viscosity (NMP) of this polyamic acid
The viscosity of this NMP solution is 2.040 poise (measured at 30℃ at a concentration of 0.5 g/100 ml).
℃). This NMP solution of polyamic acid was placed on a 35 μm thick copper foil (same dimensions as the glass plate) fixed in the same manner as in Example 1 on a glass plate of the same size as in Example 1. It was cast using the same method, heated under the same conditions as in Example 1, and then cooled to room temperature to release the copper foil from being fixed. The thickness of the polyimide film in the obtained polyimide-metal foil composite film was 28 μm, the radius of curvature of this composite film was 0.8 cm, and the curl was large. The polyimide membrane in this composite film
The average linear expansion coefficient at 50 to 250°C measured by TMA was 3.4×10 ⁻⁵ 1/°C, which was larger than the average linear expansion coefficient of copper foil in the same temperature range. Furthermore, when the 90° peel strength between the polyimide film and the copper foil was measured, it was 1.05 kg/10 mm, which was a somewhat insufficient value for an electric circuit board. Examples 2 to 5 NMP and the diamino compounds shown in Table 1 below were placed in a 500 ml flask and the diamino compounds were dissolved. In this case, the amount of NMP used was set so that the monomer concentration of the diamino compound and the aromatic tetracarboxylic acid compound described below was 15%. Next, the aromatic tetracarboxylic acid compounds shown in Table 1 were gradually added to the above system while stirring.
During this time, the reaction system was cooled with ice water so that the temperature did not exceed 30°C. Thereafter, the solution was stirred for a predetermined period of time to obtain an NMP solution of polyimide acid having a logarithmic viscosity (measured at 30° C. at a concentration of 0.5 g/100 ml in NMP) shown in Table 1. This NMP solution of polyamic acid was placed on a copper foil (same dimensions as the glass plate, thickness as shown in Table 1) fixed in the same manner as in Example 1 on a glass plate of the same size as in Example 1. , cast in the same manner as in Example 1, heated at 150°C for 30 minutes, 200°C for 60 minutes, and then cast for 300 minutes at 200°C.
Heated at ℃ for 2 hours. Then cool to room temperature,
Fixed copper foil was excluded. The thickness of the polyimide film and the radius of curvature of the resulting polyimide-metal foil composite film were as shown in Table 1. Table 1 also shows the difference in average linear expansion coefficient between 50 and 250°C measured by TMA of the polyimide film in this composite film, and the 90° peel strength in normal conditions between the polyimide film and the copper foil. Comparative Examples 2 to 5 Using the diamine compounds and aromatic tetracarboxylic acid compounds shown in Table 1, the logarithmic viscosity (0.5 in NMP) shown in Table 1 was obtained in the same manner as in Examples 2 to 5 above.
An NMP solution of polyimide acid (measured at 30° C. at a concentration of g/100 ml) was obtained. Using this NMP solution of polyamic acid, polyimide-metal foil composite films were produced in the same manner as in Examples 2 to 5 above. The radius of curvature of this composite film, the thickness of the copper foil and polyimide film, and
Table 1 shows the difference between the average linear expansion coefficient of the polyimide film and the average linear expansion coefficient of the copper foil at 50 to 250°C measured by TMA, and the 90° peel strength between the polyimide film and the copper foil in normal conditions. It is also shown in Table 1.

[Table] In Table 1, DADE is 4,4'-diaminodiphenyl ethyl ether and P-PAD is p-
Phenylene diamine, m-PDA is m-phenylene diamine, (a) and (f) are silicone diamines of the above structural formula, and s-BPDA is 3,3',4,4'-biphenyltetracarboxylic acid diamine. The anhydride, PMDA, indicates pyromellitic dianhydride, and BTDA indicates 3,3',4,4'-benzophenonetetracarboxylic dianhydride. As is clear from the above Examples and Comparative Examples, according to the manufacturing method of this polyimide-metal foil composite film, the polyimide film and the copper foil are firmly bonded, and there is virtually no curling. A composite film is obtained.

[Brief explanation of the drawing]

The drawing is an explanatory diagram illustrating the radius of curvature of a polyimide-metal foil composite film.

Claims (1)

[Claims] 1 80 to 99.9 mol% of the following component (A) and component (B)
A diamino compound containing 0.1 to 10 mol% and the following (C)
a step of preparing an organic polar solvent solution of a polyimide precursor obtained by reacting the above-mentioned polyimide precursor with a tetracarboxylic acid compound as a main component, and a step of applying the organic polar solvent solution of the polyimide precursor onto a metal foil. A polyimide-metal foil comprising the step of heating a metal foil coated with an organic polar solvent solution of the polyimide precursor in a fixed state to form a polyimide thin film on the foil surface of the metal foil. Manufacturing method for composite film. (A) p-phenylenediamine (B) General formula [In the formula, R ₁ is a methylene group, a phenylene group or a substituted phenylene group, R ₂ is a methylene group, a phenyl group or a substituted phenyl group, X is an oxygen atom,
phenylene group or substituted phenylene group, n is
When R ₁ is a phenylene group or a substituted phenylene group, it is an integer of 1, and when it is a methylene group, it is an integer of 3 or 4. ] Silicon-based diamine represented by. (C) At least one of 3,3',4,4'-biphenyltetracarboxylic dianhydride and its derivatives. 2. The method for producing a polyimide-metal foil composite film according to claim 1, wherein the metal foil has a thickness of 1 to 500 μm and the polyimide thin film has a thickness of 5 to 200 μm. 3 Logarithmic viscosity of polyimide precursor (N-methyl-
2. The method for producing a polyimide-metal foil composite film according to claim 1, wherein the polyimide-metal foil composite film has a polyimide-metal foil composite film of 0.4 to 7.0 (measured at 30° C. at a concentration of 0.5 g/100 ml in 2-pyrrolidone). 4. Claims 1 to 3 in which the metal foil is copper foil, aluminum foil, or stainless steel foil.
A method for producing a polyimide-metal foil composite film according to any one of the above items. 5. The polyimide according to any one of claims 1 to 4, wherein the difference in average linear expansion coefficient between the metal foil and the polyimide film at 50 to 250°C is within 0.3×10 ^-5 1/°C. Manufacturing method for metal foil composite film.