JPH066360B2 - Polyimide-metal foil composite film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention produces almost no curl not only in the state of a composite film, but also in the state where a metal foil is removed by etching, and has heat resistance, chemical resistance, and size. The present invention relates to a polyimide-metal foil composite film having excellent properties such as stability.

[Conventional technology]

Polyimide-metal foil composite films are used in semiconductor devices as substrates for flexible printed circuits.
Such a polyimide-metal foil composite film is subjected to circuit formation, mounted with electronic parts and the like, and incorporated into a semiconductor device or the like. Recently, the packaging density of semiconductor devices has been increased, and circuit-formed polyimide-
2. Description of the Related Art When mounting electronic components on a metal foil composite film, soldering is performed a plurality of times in the manufacturing process to mount the electronic components at high density. In this case, the mounting is performed by melting the solder at a considerably high temperature, and the polyimide-metal foil composite film is also required to have excellent properties such as heat resistance. Also, due to problems with operability, etc., it is required that the film does not warp and maintains a flat state at any stage from the formation of the circuit to the formation of the circuit and the stage after the circuit is formed by etching the metal foil. Has been done.

Conventionally, there are the following three types of methods for producing this kind of polyimide-metal foil composite film. The first method is
A second method is a method of heat-bonding the polyimide film to the metal foil, which is a method of bonding the polyimide film to the metal foil with an adhesive. The third method is a method in which a polyimide precursor or a solution of polyimide in an organic polar solvent is applied to the foil surface of a metal foil and heat-treated to form a polyimide film.

Of the above three methods, the first method is to bond the polyimide film to the metal foil with an adhesive, so that the heat resistance and heat shock resistance of the entire polyimide-metal foil composite film may be affected by the effect of the adhesive. It has the drawback of decreasing. In addition, since it is necessary to form a film of polyimide, there is a drawback that the process becomes long. Since the second method does not use an adhesive, it does not have the drawbacks of the first method, but it still requires a step of forming a film of polyimide, and thus has a drawback of lengthening the step. Since the third method does not require the use of an adhesive or the formation of a polyimide film, the advantages described above do not occur and a thin polyimide-metal foil composite film can be obtained. is there. However,
Since the polyimide-metal foil composite film obtained by this method requires a high temperature to form the polyimide resin layer, a difference in the coefficient of contraction occurs when the temperature drops to room temperature due to the difference in the coefficient of thermal expansion between the metal foil and the polyimide resin layer. However, there is a problem in that the composite film is curled. If such curl occurs, it not only hinders the photoresist printing in the subsequent process, but also causes a problem in handleability during transportation.

Two types of methods have been proposed as methods for solving the problem of curling of the polyimide-metal foil composite film. A first method is a method of post-treating the above composite sheet to straighten the curl. For example, in Japanese Patent Laid-Open No. 54-31480, an arc type drying furnace (drum dryer) is used for the composite sheet.
Etc., a method of stretching and rolling is disclosed, and JP-A-54-66666 discloses a method of removing curl by heating at a high temperature for a long time.
Further, JP-A-54-108272 discloses a method of removing a curl by winding it in a cylindrical shape with a resin layer on the outside and heat-treating at 100 to 200 ° C. for a long time.
Japanese Patent No. 388 discloses a method of removing curls by continuously contacting the curved surface of a bar having a curved surface with a radius of curvature of 0.5 to 25 mm with the metal foil surface inside and applying tension. According to such a method, curls are considerably corrected, but various devices for post-treatment are required, and
The addition of the post-treatment process lengthens the whole process, which is problematic for practical use.

The second method is a method in which a heat-resistant resin is reacted with an epoxy, a phenoxy, and an acrylonitol-butadiene copolymer to form a three-dimensional structure, whereby curing shrinkage is suppressed and curling is prevented. According to this method, some effect can be obtained in preventing curling, but it is obtained because the resin formed has a three-dimensional structure and lacks flexibility, and the introduction of a cross-linking agent reduces heat resistance. There is a drawback that the performance of the composite sheet deteriorates.

As described above, for the polyimide-metal foil composite film, it is required not to curl in the state of the composite film from the viewpoint of operability and the like, and not to curl even in the state where the metal foil is removed by etching. .

The above-mentioned proposed methods are mainly intended to prevent the occurrence of curl in the state of the composite film, and do not consider the prevention of curl in the state after the metal foil is etched. Regarding this point, JP-A-58-155
No. 790, the curl does not occur in the polyimide resin layer (polyimide film) after the organic polar solvent solution of polyimide using a tetranuclear diamine is cast coated on a metal foil and the metal foil is removed by chemical etching. It is disclosed. However, the polyimide resin used in this proposed method is
Since the coefficient of linear expansion is considerably larger than that of metal foil such as copper foil, curling occurs at the stage of composite film.
Therefore, this causes a trouble in printing the photoresist on the polyimide-metal foil composite film, and also causes a problem in transportation and the like.

[Problems to be solved by the invention]

As described above, according to the proposed methods up to now, all have advantages and disadvantages, curl does not occur not only in the state of the composite film but also in the state of removing the metal foil by etching, and further, heat resistance, chemical resistance, dimensional stability The fact is that a polyimide-metal foil composite film excellent in properties such as properties has not been obtained.

The present invention has been made in view of such circumstances, and does not substantially curl not only in the state of the composite film but also in the state where the metal foil is removed by etching, and the characteristics such as heat resistance, chemical resistance, and dimensional stability. It is an object of the present invention to provide a polyimide-metal foil composite film excellent in heat resistance.

[Means for solving problems]

To achieve the above object, the polyimide-metal foil composite film of the present invention, on the foil surface of the conductive metal foil, represented by the repeating unit represented by the following general formula (1) and the general formula (2). The polyimide resin layer mainly composed of the repeating unit is directly formed.

In the above formula, R is a divalent organic group other than the phenylene group, and: m = 70 to 80:30 to 20.

In order to prevent the occurrence of curl of the polyimide-metal foil composite film, the present inventors focused their attention on the polyimide resin layer of the composite film, and selected organic tetracarboxylic dianhydrides and diamino compounds as starting materials for polyimide. As a result of repeated studies, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride was used as the organic tetracarboxylic dianhydride, and p was used as the diamino compound.
-By using phenylenediamine, it is found that a polyimide having a linear expansion coefficient similar to that of a metal foil is obtained, and when this is applied to a polyimide-metal foil composite film, a curl-free composite film is obtained. It was However, this composite film also prevents curling from occurring in the composite state, and thus curling occurred when the metal foil was removed by etching. Therefore, as a result of further studies, the present inventors did not use only p-phenylenediamine as the diamino compound, but used p-phenylenediamine and other diamines together, and the ratio of the two was in a molar ratio. When p-phenylenediamine is set to 70 to 80 mol% and other diamines are set to 30 to 20 mol%, curling does not occur not only in the composite state but also in the state where the metal foil is removed by etching. The inventors have reached the present invention by finding that a metal foil composite film can be obtained.

Not only in the composite state as described above, but also in the state where the metal foil is removed by etching, the polyimide resin used for the polyimide-metal foil composite film has the above general formula.
It is a polyimide resin mainly composed of repeating units represented by (1) and (2). Here, the term “main body” also includes the case where the whole body consists of only the main body.

A polyimide-metal foil composite film that does not curl not only in the state of the composite film but also in the state after etching removal by forming the polyimide resin layer of the polyimide-metal foil composite film using the above-mentioned polyimide resin Will be obtained. This is because the above polyimide resin has a linear expansion coefficient similar to that of a metal foil, and constitutes a repeating unit of the general formula (2), and by the action of a diamine other than p-phenylenediamine, an imidization reaction. It is thought that this is due to the relaxation of the stress generated during solvent removal and dehydration ring closure.

The mutual proportion of the repeating unit represented by the general formula (1) and the repeating unit represented by the general formula (2) is 70 to 80 mol% of the repeating unit represented by the general formula (1) as described above. On the other hand, the general formula (2)
The repeating unit is represented by 30 to 20 mol%. That is, the repeating unit represented by the general formula (1) is 70 mol%
If it is less than the above range, the difference in linear expansion coefficient between the metal foil and the polyimide resin layer becomes too large, and the obtained polyimide-metal foil composite film is curled. On the other hand, if it exceeds 80 mol%, the proportion of the repeating unit represented by the general formula (2) becomes too small, and the curling after etching the metal foil becomes considerably conspicuous.

The resin layer of the polyimide mainly composed of the repeating unit represented by the general formula (1) and the general formula (2), for example, the following general formula (3) And p-phenylenediamine represented by the following general formula
(4) H ₂ NR-NH ₂ (4) [R is a divalent organic group other than a phenylene group] The diamine other than p-phenylenediamine is 70 to 80 mol% of the former and the latter is A diamino compound in a proportion of 30 to 20 mol%, 3,3 ′, 4,
It can be obtained by reacting 4'-biphenyltetracarboxylic dianhydride or a tetracarboxylic dianhydride mainly containing a derivative thereof in an organic polar solvent.

Typical diamines (hereinafter abbreviated as "other diamines") other than p-phenylenediamine represented by the general formula (4) are as follows. These diamines can be used alone or in combination. m-phenylenediamine, 2,4-diaminotoluene, 4,4'-
Diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-
Diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylpropane, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenylhexafluoropropane, 4,4'-
Diaminodiphenyl sulfide, 1,4-bis (4-aminophenoxy) benzene, 4,4'-bis (4-aminophenoxy) biphenyl, 2,2-bis [4- (4-
Aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 4,4′-bis (4-aminophenoxy) diphenylsulfone, 4,4′-bis (3 -Aminophenoxy) diphenyl sulfone and the like. Among these diamines, it is most preferable to use 4,4′-diaminodiphenyl ether in terms of heat resistance, adhesion, curl reduction and the like.

In addition, in place of a part or all of the above diamine, a silicon-based diamine as shown in the following (A) to (G) can be used.

By using the silicon-based diamine as described above,
In particular, the resin layer is firmly bonded to the metal foil, and a polyimide-metal foil composite film having excellent heat resistance can be obtained. This was found by the present inventors during the study of polyimide resins used for printed circuit boards. When a siloxane bond is introduced into the molecular chain of polyimide, the polyimide produced is not only for silicon-containing substrates such as glass but also for metal foils. However, this is an application of the phenomenon of exhibiting strong adhesion.
As a result, the excellent effects as described above can be obtained.

Further, the tetracarboxylic acid dianhydrides to be reacted with the diamine compound consisting of the p-phenylenediamine and other diamines are, as described above, 3,3 ′, 4,
It is mainly composed of 4'-biphenyltetracarboxylic dianhydride or its derivative such as acid halide, diester or monoester. Usually, those containing 70% or more of this dianhydride or its derivative and 30 mol% or less of other tetracarboxylic acid dianhydride or its derivative such as acid halide, diester or monoester are used. If the proportion of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride or its derivative is too small, the coefficient of linear expansion between the metal foil and the polyimide resin becomes large, or the strength of the polyimide resin extremely decreases. It is not preferable because it causes inconvenience.

The above-mentioned other tetracarboxylic dianhydrides or derivatives thereof include pyromellitic dianhydride, 3,3 ′, 4,
4'-benzophenone tetracarboxylic dianhydride, 3,
The proportions of acid dianhydrides such as 3 ', 4,4'-biphenyltetracarboxylic dianhydride and 2,3,6,7-naphthalenetetracarboxylic dianhydride or derivatives thereof are listed, either alone or in combination. Can be used. Among the above-mentioned other tetracarboxylic dianhydrides, especially pyromellitic dianhydride or its derivative or 3,
It is preferable to use 3 ', 4,4'-benzophenone tetracarboxylic dianhydride or its derivative. That is, these tetracarboxylic acid dianhydrides are difficult to form a polyimide resin layer (polyimide film) having excellent strength even when reacted with the diamino compound alone, but the linear expansion of the polyimide resin layer The reason for this is that the reduction of the coefficient gives a favorable result and meets the purpose of the present invention of preventing curling.

The synthesis of the polymer in the present invention is carried out by reacting the above-mentioned diamino compound and tetracarboxylic dianhydrides in an approximately equimolar organic polar solvent at 0 to 90 ° C. for 1 to 24 hours, and then a polyimide precursor such as polyimide acid. It is carried out by

Examples of the organic polar solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, dimethylphosphoamide, m-cresol, p-cresol, p-chlorophenol and the like. Can be given. A part of xylene, toluene, hexane, naphtha, etc. may be used together.

The polyimide precursor thus synthesized has an inherent viscosity (0.5 g / 100 m in N-methyl-2-pyrrolidone).
Is preferably in the range of 0.4 to 7.0. More preferred is in the range 1.5 to 3.0. If this value is too small, the mechanical strength of the obtained polyimide resin layer will be low. On the contrary, if this value is too large, the coating workability on the foil surface of the metal foil will be poor, which is not preferable.

The above logarithmic viscosity is calculated by the following formula, and the fall time in the formula is measured by the capillary viscosity.

However, in the formula, t ₁ is the time for the solution to drop in the constant volume of the capillary, and t ₀ is the drop time for the solution. Further, C is the concentration expressed in g of the polymer in 100 m of the solution.

It is known that this logarithmic viscosity is directly related to the molecular weight of the polymer.

This invention uses the organic polar solvent solution of the polyimide precursor obtained as described above to produce a polyimide-metal foil composite film, for example, as follows. That is,
First, the organic polar solvent solution of the above polyimide precursor is added to 80
Heating to a temperature below ℃ to reduce the viscosity, in that state,
A metal foil having a thickness of 1 to 500 μm, preferably 10 to 100 μm, particularly preferably 20 to 50 μm is cast and coated by 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 may be reduced, and problems such as application may occur. Conversely, if it exceeds 500 μm, the obtained polyimide-metal foil composite film may be It lacks flexibility and becomes less suitable for applications such as electric circuit boards. Therefore, the metal foil used preferably has a thickness in the range of 1 to 500 μm.

As the type of the metal foil, a copper foil or an aluminum foil is preferable, and when a copper foil is used, an electrolytic copper foil, a rolled copper foil or a surface treatment of these with a silane coupling agent, an aluminum coupling agent, or the like is used. It is preferable to use it because the adhesive strength to the polyimide resin layer increases.
As the metal foil, silver having the above thickness,
Materials made of various materials such as iron, alloys of nickel and chromium, and stainless can be used. The length of these metal foils when applying the polyimide precursor solution is not particularly limited. However, the width is actually 20
It is about 200 cm. Of course, there is no problem even if it deviates from the above range. Needless to say, the polyimide-metal foil composite film obtained by using the wide metal foil may be cut into a predetermined width in the final step and used.

The organic polar solvent solution of the polyimide precursor obtained as described above may be further diluted with an organic polar solvent, if necessary. In this case, as the diluting organic polar solvent, those used at the polymerization reaction of each polyimide precursor can be used. The concentration of the polyimide precursor in the solution is preferably set to about 10 to 30% by weight. If this concentration is too low, the surface of the polyimide resin layer tends to be rough, and conversely, if it is too high, the viscosity becomes high and the coating workability is impaired. From the viewpoint of coating workability, the viscosity of this solution is generally 5000 poise or less, which is the viscosity at the time of warm coating.

Next, after the solution is applied, heat treatment is performed in a state where the above metal foil is fixed to form a polyimide resin layer. This heat treatment is usually performed by heating and drying at 100 to 230 ° C. for about 30 minutes to 2 hours to remove the solvent, and then further raising the temperature to finally reach 2
It is carried out at a temperature of 30 to 600 ° C. for 1 minute to 6 hours, preferably at a temperature near the glass transition temperature of the polyimide to be formed, that is, at a temperature of 250 to 350 ° C. for 10 minutes to 6 hours. As a result, the imidization reaction after the application of the polyimide precursor is completely performed, and the stress generated in the coating film at the time of removing the solvent and the imidization is alleviated.

When the heat treatment for imidization and stress relaxation is performed at a temperature of less than 230 ° C., not only the imidization reaction is not completely completed but also stress relaxation becomes insufficient, and the resulting polyimide-metal foil composite film is curled. Is likely to occur. Conversely, if the temperature is higher than 600 ° C., the polyimide is decomposed, which is not preferable.

Through such a series of steps, a stress-relaxed polyimide resin layer (polyimide film) is formed on the metal foil to obtain a polyimide-metal foil composite film. in this case,
It is preferable to set the thickness of the polyimide film to 5 to 200 μm. The thickness is more preferably 10 to 100 μm, and most preferably 20 to 60 μm. This thickness is 5μ
If it is less than m, the film characteristics will deteriorate, and conversely 200μ
When it exceeds m, it lacks flexibility and becomes less suitable for use as a polyimide-metal foil composite film. Therefore, the thickness of the polyimide film is 5 to 200 μm.
It is preferable to set to m.

The polyimide film generally has an average linear expansion coefficient in the range of 1.5 × 10 _{−5 to} 3.0 × 10 ₋₅ / ° C. at 50 to 250 ° C., but in some cases, an average linear expansion coefficient smaller than the above value is used. It is also possible. On the other hand, the average linear expansion coefficient of a metal foil in the same temperature range as above, for example, a metal foil having a thickness of 1 to 500 μm, is 1.5 × 10 _{−5 to} 1.7 × for a copper foil.
It is in the range of 10 _-5 / ℃, and 2.4 × 10 for aluminum foil
It is in the range of _{-5 to} 2.6 x 10 _-5 / ° C.

As described above, the present invention has a feature that the average linear expansion coefficient of the polyimide film and the metal foil can be set to substantially the same value by setting the polymer composition of the polyimide film within the specific range. .

The polyimide-metal foil composite film thus obtained has substantially no curl in both the width direction and the length direction, and the stress inside the polyimide resin layer is relieved. Therefore, after removing the metal foil by etching, Also has the excellent property of not causing curl. Moreover, due to the excellent properties of the polyimide resin, the properties such as heat resistance, chemical resistance, and dimensional stability are also excellent, and the adhesion between the polyimide resin layer and the metal foil is also excellent, so that it is particularly useful for semiconductor devices. It can be suitably applied to the above-mentioned applications and can exert excellent effects. The polyimide-metal foil composite film of the present invention can be suitably applied not only to the above-mentioned applications but also to other applications such as a solar cell substrate and a heat and corrosion resistant substrate.

〔The invention's effect〕

As described above, the polyimide-metal foil composite film of the present invention has the repeating unit represented by the general formula (1) derived from p-phenylenediamine and the general formula (2) derived from other diamines. The repeating unit represented by) is provided with a polyimide resin layer made of polyimide set to a molar ratio of 70 to 80:30 to 20, so that not only the composite state but also the metal foil was removed by etching. It does not cause curl even in the state, and has excellent properties such as heat resistance, chemical resistance, and dimensional stability, and can be suitably applied to semiconductor devices and the like.

Next, examples will be described together with comparative examples.

Example 1 In a 500 cc flask equipped with a stirrer and a thermometer, p
-7.56 g (0.07 mol) of phenylenediamine (p-PDA) and 6.0 of diamine phenyl ether (DADE)
g (0.03 mol) and 200 g of N-methyl-2-pyrrolidone (NMP) were added and stirred to dissolve the diamine.

Next, 29.4 g (0.1%) of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) was added to this system.
Mol) was gradually added, and then stirring was continued at a temperature of 30 ° C. or lower for 3 hours to obtain a polyimide precursor solution having a concentration of 17.7% by weight. Intrinsic viscosity of this polyimide precursor solution (NM
P concentration of 0.5g / 100m, measured at 30 ° C) is 1.9
4 and the solution viscosity was 8600 poise (30 ° C.).

Next, the polyimide precursor solution is heated to 60 ° C.,
A rolled copper foil having a thickness of 35 μm was cast-coated using an applicator and heated at 100 ° C. for 30 minutes, 200 ° C. for 1 hour and further at 300 ° C. for 2 hours to obtain a polyimide-metal foil composite film. Next, this was cooled to room temperature and the curl of the composite film was measured by the following measuring method, and the radius of curvature was 74 mm. Further, when the curl of the polyimide film after etching and removing the copper foil of the composite film with an aqueous solution of ferric chloride was measured, the radius of curvature was 105 mm, and the average linear expansion coefficient at 50 to 250 ° C. was 2.33 ×. It was 10 ^-5 / ° C.

[Radius of curvature measurement method]

As shown in the drawing, the radius of curvature is 10 cm in length and 10 cm in width for the composite film 3 including the metal foil 1 and the polyimide film 2.
For a test piece cut into 10 cm squares of 10 cm, the degree of curvature when the test piece curls in the width direction (or the length direction) is represented by a radius r from the center P. The radius of curvature r is a point where the length in the width direction (or the length direction) in the curled state is a, and the perpendicular line N is drawn from the center P to the horizontal line M connecting both ends in the width direction (length direction). The height from R to the center of the film on the extension of the perpendicular line N is h
Then, when h ≧ r, this r can be actually measured, and when h <r, the a value and the h value can be conveniently measured and calculated from the above equation.

[Measurement Method of Average Linear Expansion Coefficient] The average linear expansion coefficient is shown as an average value of the above linear expansion coefficients in a constant temperature range. Here, the linear expansion coefficient means Δ / when the length of the material at the temperature T changes by Δ when the temperature changes by 1 ° C.
It is shown by. The coefficient of linear expansion was measured by fixing a test piece obtained by cutting the composite film into a length of 25 mm and a width of 3 mm with one end in the length direction facing upward and applying a load of 15 g / mm ² at a chuck distance of 10 mm. In this state, the temperature is changed at a temperature rising rate of 10 ° C./min in a nitrogen gas atmosphere, and the above Δ / at this time is obtained.

Comparative Example 1 In a 500 cc flask equipped with a stirrer and a thermometer, p
-PDA 10.8 g (0.10 mol) and N-methyl-2-
200 g of pyrrolidone (NMP) was put and stirred to dissolve the diamine.

Next, 29.4 g (0.1%) of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) was added to this system.
Mol) was gradually added, and then stirring was continued for 3 hours at a temperature of 30 ° C. or lower to obtain a polyimide precursor solution having a concentration of 16.7%. Intrinsic viscosity of this polyimide precursor solution (in NMP
The concentration was 0.5 g / 100 m, measured at 30 ° C.) was 2.11, and the solution viscosity was 5300 poise (30 ° C.).

Next, the polyimide precursor solution is heated to 60 ° C.,
It was cast-coated on a rolled copper foil having a thickness of 35 μm using an applicator, and heated at 100 ° C. for 30 minutes, 200 ° C. for 1 hour, and further 300 ° C. for 2 hours. When the composite film was cooled to room temperature and the curl of the composite film was measured, the bending radius was 320.
It was mm. Further, when the curl of the coating film after etching and removing the copper foil with an aqueous ferric chloride solution was measured, the bending radius was 15 mm, and the average particle linear expansion coefficient at 50 to 250 ° C. was 1.55 ×. It was 10 ⁻⁵ / ° C. Although the curl of the composite film was extremely small,
It is considered that since the molecular structure of the polyimide was too rigid, the stress was not relaxed and the coating film curled.

[Examples 2 to 6 and Comparative Examples 2 to 6] A polyimide-metal foil was prepared in the same manner as in Example 1 using the diamino compound, aromatic tetracarboxylic dianhydride, polymerization solvent and metal foil shown in Table 1. A composite film was made. Curvature radius of curl of the obtained composite film and curl radius of curl of polyimide film after etching,
The linear expansion coefficient was as shown in Table 1. In Table 1, the radius of curvature and the coefficient of linear expansion are measured as described above.

From the results shown in Table 1, it can be seen that the composite films of Examples have extremely small curl not only in the composite state but also in the state where the metal foil is removed by etching (only the polyimide film), as compared with the comparative example.

In Table 1, BAPP is 2,2-bis [4
-(4-aminophenoxy) phenyl] propane, BT
DA is 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, and DMAc is dimethylacetamide. In addition, p-PDA, DADE, s-BPDA, N
MP is as described above.

[Brief description of drawings]

The drawing is an explanatory view for explaining the radius of curvature of the polyimide-metal foil composite film. 1 ... Metal foil, 2 ... Polyimide film, 3 ... Composite film

Claims (2)

[Claims] 1. The following general formula (1) is provided on the foil surface of the conductive metal foil.
A polyimide-metal foil composite film, wherein a polyimide resin layer mainly comprising a repeating unit represented by and a repeating unit represented by the general formula (2) is directly formed. In the above formula, R is a divalent organic group other than the phenylene group, and: m = 70 to 80:30 to 20. 2. R in the general formula (2) is The polyimide-metal foil composite film according to claim 1, wherein