JPH07102649B2 - Manufacturing method of metal foil laminated film - Google Patents

Description

The present invention relates to a "thermocompression-bonding aromatic polyimide formed by a multi-layer extrusion molding method by a combination of different polyamic acid solution co-extrusion-casting film forming methods. Of a specific heat-resistant aromatic polyimide substrate layer is integrally laminated on at least one side of the substrate, and a "metal foil" is supplied between a pair of heat rolls. Then, the metal foil laminated film (for example, a non-adhesive-type copper-clad film) is directly and integrally thermocompressed between the surface of the thermocompression-bonding thin layer and the surface of the metal foil. substrate)"
The present invention relates to a method for continuously producing

The metal foil laminated film of the present invention is a support comprising an aromatic polyimide film obtained by multi-layer extrusion molding by a combination of the above-mentioned different polyamic acid solution coextrusion-casting film forming method, having extremely high heat resistance and dimensions. In addition to having stability and mechanical properties, the bonding between the multilayer extruded polyimide film and the metal foil does not require the use of a thermosetting adhesive, etc. Since the thin layer of the aromatic polyimide and the metal foil are bonded by thermocompression bonding, for example, even if the metal foil laminated film is exposed to a high temperature such as a solder bath, its adhesiveness is maintained at a sufficiently high level. Therefore, the support film is not substantially thermally deteriorated.

[Description of Prior Art]

Conventionally, a composite material (for example, a copper clad substrate) composed of a metal foil and a heat-resistant film (for example, an aromatic polyimide) support is used to bond an aromatic polyimide film and a metal foil to “thermosetting adhesive such as epoxy resin. It has been common to manufacture them by laminating them by heat-bonding via "agent".

However, the thermoset adhesive layer in the composite material is
The temperature at which the product can be used at all times, at which proper adhesive strength can be maintained, is at most 20
Since it was 0 ° C or less, there is a problem that it cannot be used in processing processes exposed to high temperatures such as soldering or in applications exposed to high temperatures, and it is more heat resistant as a composite material of metal foil and heat resistant film. It was expected to have a certain nature.

As a countermeasure, various studies have been conducted on heat-resistant adhesives, but adhesives with high heat resistance require a high temperature in the laminating process or a complicated laminating process,
In addition, there are problems that the obtained laminate often does not exhibit sufficient adhesiveness, which is not practical.

On the other hand, without using any thermosetting adhesive,
Several methods for producing an "adhesive-free composite material" in which a metal layer is formed on an aromatic polyimide film support have also been studied.

For example, as a method for producing the "adhesive-free composite material", a method for producing a composite material by casting a solution of an aromatic polyimide precursor (aromatic polyamic acid) on a metal foil to form a film, Alternatively, a method of manufacturing a composite material by plating a metal on an aromatic polyimide film and / or vacuum-depositing it has been proposed.

However, in the above-mentioned casting film forming method, it is extremely difficult to sufficiently thicken the polyimide layer that is the support layer, or the solvent evaporation / removal step in the film forming step becomes extremely long. There was a problem that productivity was low.
In addition, it is difficult for the metal plating method and / or the metal vapor deposition method described above to sufficiently increase the thickness of the metal layer, and in this respect, the productivity is low.

Further, recently, a method for producing a laminated material by laminating a thermoplastic polyimide film and a metal foil (JP-A-62-53827), and a metal foil and an aromatic polyimide having a second-order transition temperature A method of producing a laminated material by superimposing a film and an aromatic polyimide film having high heat resistance, and thermally press-bonding (JP-A-62-104840, JP-B-61-15825), Proposed.

However, the above-mentioned thermoplastic polyimide is a laminate material obtained by a method of laminating using a polyimide having Tg, the support layer has a low level in heat resistance and thermal dimensional stability, or in a solder bath. There is a problem that the adhesiveness (solder heat resistance etc.) is low when subjected to a high temperature history, or the number of heating steps is equal to the number of layers to form the polyimide, and the productivity is low. There was a problem.

Further, as the aromatic polyimide having high heat resistance and dimensional stability, an aromatic polyimide having high heat resistance obtained from biphenyltetracarboxylic acids and phenylenediamines has been proposed in Japanese Patent Publication No. 2-373. However, the film made of the aromatic polyimide described above has the adhesiveness and heat resistance obtained even when the metal foil is adhered using an adhesive by various known methods as described above. There was a problem with the low level.

[Problems to be solved]

The object of the present invention is to provide a support mainly composed of a film made of a highly heat-resistant aromatic polyimide obtained from biphenyltetracarboxylic acids and phenylenediamines, and a metal foil, using a thermosetting adhesive at all. Without, without being adhered and laminated integrally with a high adhesive force, it is to provide a method capable of easily producing a metal foil laminated film consisting of a support made of only aromatic polyimide and a metal foil. .

[Means for solving problems]

According to the present invention, a thin layer B having a thickness of 0.4 to 12 μm made of an aromatic polyimide having a thermocompression bonding property obtained from an aromatic tetracarboxylic acid and an aromatic diamine having a plurality of benzene rings is a biphenyltetracarboxylic acid. 55% of the total thickness of the multilayer extruded polyimide film, which consists of a highly heat-resistant aromatic polyimide obtained from phenylene diamines and
The thin extruded polyimide film having a thickness of 6 to 200 μm and integrally laminated on at least one side of the base layer A having a thickness of 6 to 200 μm by a combination of coextrusion of different polyamic acid solution and casting film forming method. The metal foil is superposed on the layer, and then the superposed body is continuously supplied between a pair of hot rolls, and the temperature is 280 ° C to 550 ° C and 10 to 5000 kg / c.
The present invention relates to a method for producing a metal foil laminated film, which comprises continuously performing thermocompression bonding with a linear pressure between heat rolls of m (value obtained by dividing the load between heat rolls by the width of a long multilayer extruded film).

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an outline of an apparatus for lamination used in the manufacturing method of the present invention.

FIG. 2 is a cross-sectional view showing an example of a two-layer metal foil laminated film composed of a multilayer extruded polyimide film (support film) and a metal foil manufactured by the manufacturing method of the present invention,
FIG. 3 is a cross-sectional view showing an example of a three-layer metal foil laminated film including the above-mentioned multilayer extruded polyimide film (support film) and metal foil laminated on both sides thereof.

Furthermore, FIG. 4 and FIG. 5 are cross-sectional views showing examples of the two-layer and three-layer extruded polyimide films used in the production method of the present invention, respectively.

The multilayer extruded polyimide film (support film) used in the production method of the present invention is, for example, as shown in FIGS. 4 and 5, “(a) 2,3,3 ′,
4'- or 3,3 ', 4,4'-biphenyltetracarboxylic acid or its acid dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic acid or its acid dianhydride, 3,3 ' Aromatic tetracarboxylic acids such as 4,4,4'-diphenyl ether tetracarboxylic acid or its dianhydride and an aromatic diamine having a plurality (preferably 2 to 5) of benzene rings are polymerized and imidized. It consists of the obtained "thermocompression-bonding aromatic polyimide", and (a thin layer B having a thickness of 0.4 to 12 µm, particularly preferably 0.5 to 10 µm) is obtained from "biphenyltetracarboxylic acids and phenylenediamines". Which is made of a highly heat-resistant aromatic polyimide and has a thickness of 55% or more, particularly 60% or more, of 6 to 200 μm (preferably 7 to 180 μm) of the total thickness of the multilayer extruded polyimide film. Especially 10-16
0 μm) on at least one side of the base layer A ”, the base layer A and the thin layer dope are laminated by a co-extrusion-solution casting film forming method. It is composed of.

When the thickness of the thin layer B is out of the above range, the adhesive strength and solder resistance of the obtained metal foil laminated film are deteriorated and the physical properties of the base layer itself are impaired.

The above-mentioned multilayer extruded polyimide film can be produced, for example, by the method described in the "application specification of Japanese Patent Application No. 1-317706" filed by the applicant.

That is, the multilayer extruded polyimide film is a first aromatic polyamic acid solution in which an aromatic polyamic acid obtained from aromatic tetralbonic acids and aromatic diamines having a plurality of benzene rings is uniformly dissolved. (Dope solution for thin layer) and second aromatic polyamic acid solution in which aromatic polyamic acid obtained from biphenyltetracarboxylic acid and phenylenediamine are uniformly dissolved (dope solution for substrate layer) And are simultaneously supplied to an extrusion molding machine having two or more layers of extrusion molding die, and both solutions are discharged from the outlet of the die as a thin film body of at least two layers on a smooth support (metal support). Continuously, and the multilayer thin film on the support is dried to evaporate the solvent to a considerable extent to remove the self-supporting multilayer film (including a part of the solvent). The solvent is substantially removed by heat-treating the multilayer film at a high temperature (250 to 600 ° C.). At the same time, the polyamic acid can be imidized and continuously produced.

The multilayer extruded polyimide film has an overall thickness of 6
To 250 μm, especially 8 to 200 μm, more preferably 10 to 15
It is preferably a long multi-layer film having a width of about 0 μm and a width of 5 to 200 cm, particularly 10 to 150 cm.

When the cross-section of the above-mentioned multilayer extruded polyimide film is observed by an electron micrograph, it is observed that the thermocompression-bonding thin layer B has a scaly pattern in a strip shape, and in particular, the highly heat-resistant base layer A and the thin layer. A thick thick line-shaped pattern is clearly observed along the boundary with B. However, this multilayer extruded polyimide film cannot be separated into two layers at the above-mentioned boundary portion at all, and each polyimide layer is substantially continuously and integrally and firmly bonded to each other. The film is formed.

In the metal foil laminated film of the present invention, the multilayer extruded polyimide film may be a film having a two-layer structure composed of a base layer A and a thin layer B as shown in FIG. As shown in FIG.
It may be a film having a three-layer structure composed of B and B '.

The three-layer structure film is a thermocompression-bonding thin layer B and B '.
And are almost the same thickness (thin layer thickness ratio B / B 'is 0.8 to 1.2,
It is most preferable that it is within the range of 0.9 to 1.1) because the curling property becomes extremely small.

The highly heat-resistant aromatic polyimide forming the base layer A is an aromatic tetracarboxylic acid component containing 60 mol% or more, particularly 80 mol% or more of biphenyltetracarboxylic acid or its dianhydride. A high molecular weight aromatic polyimide obtained by polymerization and imidization from an aromatic diamine component containing phenylenediamines in an amount of 50 mol% or more, particularly 60 mol% or more (preferably having a second-order transition temperature). Aromatic polyimide) is preferable from the viewpoint of heat resistance, mechanical strength, dimensional stability and the like (see, for example, Japanese Patent Publication No. 2-373 and Japanese Patent Publication No. 60-42817).

The aromatic polyimide forming the thin layer B includes an aromatic tetracarboxylic acid component containing biphenyltetracarboxylic acids in an amount of 60 mol% or more, particularly 80 mol% or more, and a diphenylether-based diamine or diaminodiphenyl, for example. An aromatic diamine component mainly containing "aromatic diamine having a plurality of benzene rings" such as alkane-based diamine, diphenylsulfone-based diamine, di (aminophenoxy) benzenes, and di [(aminophenoxy) phenyl] sulfone. Obtained by polymerization and imidization, a second-order transition temperature of 250
Aromatic polyimide having a temperature of 400 to 400 ° C., particularly 260 to 360 ° C. is preferable because it is excellent in thermocompression bonding property with a metal foil and heat resistance.

The metal foil used in the metal foil laminated film of the present invention includes iron, aluminum, copper, gold, silver, lead,
It may be a conductive metal foil made of at least one metal or alloy selected from the group consisting of magnesium,
Particularly, the thickness is 5 to 100 μm, more preferably 10 to 60 μm.
A long copper foil having a width of m and a width of 5 to 200 cm can be preferably mentioned.

The manufacturing method of the present invention is to directly layer (without using a thermosetting adhesive or the like) a “long metal foil” on a thin layer of the aforementioned “long multilayer extruded polyimide film”. Together, the polymer was fed between a pair of hot rolls at 280 ° C.
~ 550 ℃ (preferably 300-500 ℃) crimping temperature, and 10-50000 kg / cm (preferably about 20-1000 kg / cm)
It is carried out by continuous thermocompression bonding with the line pressure between the heat rolls.

In the production method of the present invention, the thermocompression bonding operation is carried out in an atmosphere of an inert gas such as nitrogen gas, neon gas, or argon gas, or a metal foil such as a copper foil in order to prevent thermal deterioration of the metal foil such as a copper foil. It is preferable that a metal foil (for example, a stainless steel foil, an aluminum foil, etc.) for preventing thermal deterioration is superposed on the top and subjected to thermocompression bonding at high temperature.

The manufacturing method of the present invention can be continuously carried out using, for example, the apparatus shown in FIG. 1 and using a long multilayer extruded polyimide film and a metal foil.

As the manufacturing method of the present invention, using the apparatus shown in FIG. 1, the long double-layer extruded polyimide film 10 (high heat-resistant base layer A and thermocompression-bonding thin layer) from the raw material supply roll 7 is used. B, with its thermocompression bonding thin layer B facing up)
Via expander roll 1, guide roll 2, etc.
In a tense state, while supplying between the pair of heat rolls 3 and 4 (elastic roll or metal roll), a long metal foil 20 from the raw material supply roll 6 is passed through the expander roll 1 or the like in a tense state. Then, it is supplied between the pair of heat rolls, both are directly superposed, thermocompression-bonded by the heat rolls 3 and 4, laminated integrally, and the laminate is cooled if necessary, Finally, with the take-up roll 5,
It is preferable to continuously produce a metal foil laminated film at a winding speed of 1 to 200 cm / min, particularly 5 to 100 cm / min.

In the manufacturing method of the present invention, when a long three-layer extruded polyimide film is used, the three-layer extruded polyimide film 10 is supplied from the raw material supply roll 7 at the center of the apparatus shown in FIG. At the same time, the metal foils 20 and 20 'are simultaneously supplied from the upper and lower raw material supply rolls 6 and 8, and the three members are overlapped and supplied between the heat rolls 3 and 4, so that thermocompression bonding can be performed.

As shown in FIGS. 2 and 3, the metal foil laminated film obtained by the production method of the present invention has a thin layer B of the multilayer extruded polyimide film (support film) 10 and the metal foil 20 ( Or 20 ') is directly thermocompressed and its adhesive strength (90 ° -peeling method) is at least 0.
6 kg / cm, particularly about 0.7 to 5 kg / cm, and the peeling interface is the interface between the surface of the thin layer B and the surface of the metal foil,
Substantially no peeling occurs at the interface between the base layer A and the thin layer B. Further, the solder bath (approx.
It is excellent in heat resistance because it does not swell or peel off on the thermocompression-bonded surface after being floated for a second and brought into contact with it.

〔Example〕

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

In the examples and comparative examples, the following measurement tests were performed on each polyimide film.

The tensile test was carried out by a method according to ASTM D-882, and the tensile strength, elongation rate (break point) and elastic modulus were measured.

As for the heat shrinkage rate, the dimensional change rate was measured when the sample film was heated at 400 ° C. for 2 hours and then gradually cooled.

The linear expansion coefficient was measured at a temperature in the range of 50 to 300 ° C for the sample film after heat treatment at 400 ° C.

In addition, in Examples and Comparative Examples, the adhesive strength of the metal foil laminated film was measured according to "90 ° -peeling method" of IPC-TM- (2.4.9.), And its solder resistance was IPC- T
Using the measurement method based on M-650 (2.4.13), the metal foil laminated film of the sample was placed in a solder bath maintained at a temperature of 288 ± 5 ° C for 10 seconds so that the metal foil side and the solder bath contacted each other. The method was carried out by floating and visually observing the presence or absence of swelling or peeling of the metal foil laminated film (determining the quality).

Example 1 3,3 ′, 4,4′-biphenyltetocarboxylic dianhydride (s
-BPDA) and 4,4'-diaminophenyl ether (DAD
E) and were polymerized in N, N'-dimethylacetamide (DMAc) to prepare a first aromatic polyamic acid solution having a polymer concentration of 18% by weight and a solution viscosity of 5000 poise.

On the other hand, s-BPDA and para-phenylenediamine (PPD) are polymerized in DMAc to give a monomer concentration of 18% by weight and a solution viscosity of 45%.
A 00 poise second aromatic polyamic acid solution was prepared.

Using the first and second aromatic polyamic acid solution, from a two-layer extrusion die, extruded and cast on the upper surface of a smooth metal support, continuously dried by hot air at 140 ℃, Solidified film (self-supporting film, solvent content; 3
5% by weight), and after peeling the solidified film from the support, the temperature is gradually raised from 200 ° C to 550 ° C in a heating furnace to remove the solvent and imidize the polymer,
A long bilayer extruded polyimide film (width: 20 cm) was produced. Table 1 shows the physical properties (tensile test, heat shrinkability, linear expansion coefficient) of this two-layer extruded polyimide film.

The above-mentioned two-layer extruded polyimide film is a base layer A made of a highly heat-resistant aromatic polyimide (no second-order transition temperature).
Has a thickness of 32 μm, and the thin layer B made of thermocompression-bonding aromatic polyimide (secondary transition temperature 280 ° C.) has a thickness of 3 μm.
Met.

Then, using the apparatus shown in FIG. 1, while supplying the long double-layer extruded polyimide film 10 from the raw material supply roll 7 such that the thin layer B is on the upper side,
A long 35 μm copper foil 20 is supplied from the raw material supply roll 6 and the both are overlapped with the expander roll 1 or the like,
Then, it supplied to the heat rolls 3 and 4, and thermocompression-bonded on the conditions shown in Table 1, and manufactured the metal-foil laminated polyimide film.

Regarding the above-mentioned metal foil laminated film, its adhesive strength (90
(Peeling, room temperature) and solder resistance were measured. The results are shown in Table 1.

Example 2 A metal foil laminated polyimide film was produced in the same manner as in Example 1 except that the conditions shown in Table 1 were adopted as the thermocompression bonding conditions.

The adhesive strength and solder resistance of these metal foil laminated films are shown in Table 1.

Example 3 A two-layer extrusion polyimide film having a thickness (base layer A and thin layer B) having the thickness shown in Table 1 was produced by changing the discharge rate of the two-layer extrusion polyimide film. A metal foil laminated polyimide film was produced in the same manner as in Example 2 except that was used. The adhesive strength and solder resistance of these metal foil laminated films are shown in Table 1.

Examples 4 to 7 In the same manner as in Example 1 except that the discharge amount was changed by using a three-layer extrusion die, a three-layer extruded polyimide film having the constitution shown in Table 2 (thermocompression bonding on both sides of the base layer A) was performed. (With a thin layer B and B '). Table 1 shows the physical properties (tensile test, heat shrinkability, linear expansion coefficient) of this three-layer extruded polyimide film.

The above three-layer extruded polyimide film is used as a raw material supply roll 7
Each of the metal foil laminated polyimide films was prepared in the same manner as in Example 1 except that long copper foil was supplied from the raw material supply rolls 6 and 8 and the thermocompression bonding conditions were as shown in Table 1. Each was manufactured.

Table 2 shows the adhesive strength and solder resistance of each of the above metal foil laminated films.

Comparative Examples 1-2 The second-order transition temperature is 280 ° C. under the same molding conditions as in Example 1 except that the first aromatic polyamic acid prepared in Example 1 is used and a single layer extrusion die is used. Thickness 75
A μm aromatic polyimide film (single layer film, called R ₁ type) was manufactured. The physical properties of those films are shown in Table 1.

Using the above single layer aromatic polyimide film,
A metal foil laminated polyimide film was produced in the same manner as in Example 1 except that the thermocompression bonding conditions shown in the table were used. The adhesive strength and solder resistance of the metal foil laminated film are shown in Table 1.

Comparative Example 3 Using the first aromatic polyamic acid prepared in Example 1 and using a single layer extrusion die, the same molding conditions as in Example 1 except that the second transition temperature was 285 ° C. 15
A μm aromatic polyimide film (single layer film, called R ₂ type) was manufactured.

Using the second aromatic polyamic acid prepared in Example 1 and using a single layer extrusion die, the molding conditions were the same as in Example 1 except that there was no second transition temperature.
A μm aromatic polyimide film (single layer film, called R ₁ type) was manufactured.

The raw material supply roll 8 supplies the S ₁ type single layer film, the raw material supply roll 7 supplies the R ₂ type single layer film, and the raw material supply roll 6 supplies the long copper foil. Metal foil laminated polyimide films were produced in the same manner as in Example 1 except that the thermocompression bonding conditions shown in Table 1 were used. The adhesive strength and solder resistance of the metal foil laminated film are shown in Table 1.

[Operation and Effect of the Present Invention] The method for producing a metal foil laminated film of the present invention is a method capable of easily producing an excellent metal foil laminated film with good reproducibility.

The metal foil laminated film, the support "multilayer extruded polyimide film", the "base layer" is formed with a high heat-resistant specific aromatic polyimide,
Since it has a "thin layer" made of a specific aromatic polyimide having thermocompression bonding property on at least one surface, the support has extremely excellent heat resistance, mechanical properties, and electrical characteristics. At the same time, the adhesiveness between the metal foil of the metal foil laminated film and the multilayer extruded polyimide film is strong, the heat resistance is extremely excellent, and the solder resistance is particularly high.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an outline of an apparatus for lamination used in the manufacturing method of the present invention. FIG. 2 is a cross-sectional view showing an example of a two-layer metal foil laminated film composed of a multilayer extruded polyimide film (support film) and a metal foil manufactured by the manufacturing method of the present invention,
FIG. 3 is a cross-sectional view showing an example of a three-layer metal foil laminated film including the above-mentioned multilayer extruded polyimide film (support film) and metal foil laminated on both sides thereof. Furthermore, FIG. 4 and FIG. 5 are cross-sectional views showing examples of the two-layer and three-layer extruded polyimide films used in the production method of the present invention, respectively. A; substrate layer, B and B '; thin layers 1 and 2; expander roll, 3 and 4; thermo roll,
5: Take-up roll, 6, 7 and 8; Raw material supply roll, 9;
Heating furnace, 10; multilayer extruded film, 20; metal foil.

Claims (1)

[Claims] 1. A thin layer B having a thickness of 0.4 to 12 .mu.m, comprising a thermocompression-bonding aromatic polyimide obtained from aromatic tetracarboxylic acids and an aromatic diamine having a plurality of benzene rings, is biphenyltetra At least one side of the base layer A made of a high heat-resistant aromatic polyimide obtained from carboxylic acids and phenylenediamines and having a thickness of 55% or more of the total thickness of the film and a thickness of 6 to 200 μm. Coextrusion of heterogeneous polyamic acid solution integrally laminated on
A metal foil is superposed on the thin layer of the multilayer extrusion polyimide film by a casting film forming method, and then the superposed body is continuously supplied between a pair of hot rolls, 280 ° C to 550.
At a temperature of ℃ and a line pressure between hot rolls of 10-5000 Kg / cm,
A method for producing a metal foil laminated film, which comprises continuously performing thermocompression bonding.