JP4510506B2 - Method for producing polyimide metal laminate - Google Patents

Description

  The present invention relates to a polyimide metal laminate widely used for flexible wiring boards and the like.

  In recent years, as electronic devices have become smaller and more portable, flexible wiring boards have become thinner and denser. Furthermore, the proportion of lead-free solder used in component mounting has increased, and the temperature during component mounting and repair has become higher than the conventional temperature, and high heat resistance is required. With the demands for thinning of flexible wiring boards, high density wiring, and high heat resistance, demands for thinning, high dimensional stability, and high heat resistance are increasing in polyimide metal laminates as circuit board materials.

  As a polyimide metal laminate as a circuit board material, as disclosed in Patent Document 1 (Patent No. 2746555) and Patent Document 2 (Japanese Patent Laid-Open No. 2001-270037), a flexible film in which copper foil and polyimide are laminated is used. Circuit boards are known. This polyimide metal laminate is obtained by laminating polyimide on a metal foil by casting or laminating method. In order to improve the adhesion between the metal foil layer and the polyimide layer, a thermoplastic polyimide between the metal foil layer and the polyimide layer is obtained. Is generally used.

As a problem in thinning the polyimide layer of the polyimide metal laminate, the thermoplastic polyimide resin has a larger coefficient of linear expansion than the non-thermoplastic polyimide resin and is inferior in heat resistance. When the thickness is reduced, the thickness ratio of the thermoplastic polyimide layer to the entire thickness of the polyimide layer is increased, and the dimensional stability and heat resistance are lowered. Further, when the thickness ratio of the thermoplastic polyimide resin is lowered, there is a problem that the adhesion at the polyimide interlayer interface in the laminate or the interface between the metal foil layer and the polyimide interlayer is lowered. Furthermore, when the thickness ratios of the thermoplastic polyimide layers in contact with the metal foil are different, problems such as an increase in warpage occur, and it is difficult to make the polyimide metal laminate thin.
Patent No. 2746555 JP 2001-270037 A

  The object of the present invention is to provide performances such as peel strength, dimensional stability, heat resistance, warpage, voids, etc. in a polyimide laminate between polyimide layers or between a polyimide layer and a metal layer and a polyimide layer, in a polyimide laminate using thermoplastic polyimide. The present invention provides a manufacturing method for thinning a polyimide layer of a polyimide metal laminate without reducing it, and a polyimide metal laminate obtained by this production method.

  As a result of investigations, the present inventors configured a metal foil (a) layer, a thermoplastic polyimide (A) layer, a non-thermoplastic polyimide (B) layer, a thermoplastic polyimide (C) layer, and a metal foil (b) layer in this order. The present inventors completed the present invention by discovering a novel manufacturing method that enables the polyimide layer of the resulting polyimide metal laminate to be thinned.

  That is, the present invention comprises a metal foil (a) layer, a thermoplastic polyimide (A) layer, a non-thermoplastic polyimide (B) layer, a thermoplastic polyimide (C) layer, and a metal foil (b) layer in this order. In the method for producing a polyimide metal laminate, after forming a thermoplastic polyimide (A) layer and a non-thermoplastic polyimide (B) layer on the metal foil layer (a) in sequence, the thermoplastic polyimide (C) layer is non-heated. It is formed on the plastic polyimide (B) layer and / or the metal foil (b) layer, and the B layer-C layer or the C layer-C layer and the C layer-metal foil (b) layer are bonded by thermocompression bonding. It is related with the manufacturing method of the polyimide metal laminated board characterized, and the polyimide metal laminated board obtained by this manufacturing method. Here, when the C layer and the C layer are bonded together by thermocompression bonding, the C layer formed on the non-thermoplastic polyimide (B) layer and the C layer thermoplastic polyimide resin formed on the metal foil (b) layer Structures having different compositions are also included in the present invention.

  According to the present invention, the total polyimide layer thickness of the polyimide metal laminate can be reduced to 25 μm or less without deteriorating the peel strength, dimensional stability, heat resistance, warpage, voids, etc. of the polyimide metal laminate. It became.

Hereinafter, the present invention will be described in detail.
The polyimide metal laminate produced by the present invention comprises a metal foil (a) layer, a thermoplastic polyimide (A) layer, a non-thermoplastic polyimide (B) layer, a thermoplastic polyimide (C) layer, and a metal foil (b) layer. In this order, a thermoplastic polyimide (A), a non-thermoplastic polyimide (B), a thermoplastic polyimide (C) and / or a precursor thereof and / or a varnish containing them is used as a metal foil (a ) After coating, drying and curing in the order of A and B on the layer, C is formed on the B layer and / or the metal foil (b) layer, and B layer-C layer or C layer-C layer, It is manufactured by bonding between the C layer and the metal foil (b) layer by thermocompression bonding. Here, when the C layer and the C layer are bonded together by thermocompression bonding, the C layer formed on the non-thermoplastic polyimide (B) layer and the C layer thermoplastic polyimide resin formed on the metal foil (b) layer Structures having different compositions are also included in the present invention.

  The metal used in the present invention is at least one metal selected from the group consisting of copper, nickel, cobalt, chromium, zinc, aluminum and stainless steel, and alloys thereof, more preferably copper and copper alloys. , Stainless steel and its alloys, nickel and nickel alloys (including 42 alloys), aluminum and aluminum alloys, and the like. More preferred are copper and copper alloys. The thickness of the metal is not limited as long as it can be used in a tape shape, but is preferably 1 to 150 μm, more preferably 1 to 30 μm. In addition, there is no problem even if the types of the metal layer (a) and the metal layer (b) of the polyimide metal laminate of the present invention are the same or different. Preferably, both are copper cases.

  The total thickness of the polyimide layer in the polyimide metal laminate (total thickness of the thermoplastic polyimide (A) layer, non-thermoplastic polyimide (B) layer, thermoplastic polyimide (C) layer) is preferably 25 μm or less, More preferably, they are 3 micrometers or more and 20 micrometers or less, More preferably, they are 5 micrometers or more and 15 micrometers or less.

  The thickness of each polyimide layer of the polyimide layer is preferably 0.1 to 5 μm for the A layer, more preferably 0.2 to 4 μm, still more preferably 0.3 to 3.5 μm, and still more preferably 0.4. About 3 μm. The B layer is preferably about 1 to 24.8 μm. Moreover, in order not to lower the peel strength of the thermocompression bonding surface, the C layer is preferably about 0.1 to 5 μm, more preferably 0.2 to 4 μm, still more preferably 0.3 to 3.5 μm, and still more. Preferably, it is about 0.4 to 3 μm. Note that these thicknesses are only a guide and are not particularly limited.

  Further, the higher the thickness ratio of the non-thermoplastic polyimide (B) in the total polyimide layer thickness, the better the dimensional stability, and the more equal the thickness ratio of the A layer and the C layer, the better the warp and the better. Accordingly, the thickness ratio of each layer can be in the range of A layer: B layer: C layer = 1: 1.5: 0.3 to 1: 248: 3, preferably 1: 1.5: 0.5-1: 248: 2, more preferably 1: 1.5: 0.7-1: 248: 1.3, more preferably 1: 1.5: 0.8-1: 248: 1. 2.

  In the present invention, the thermoplastic polyimide (A) has a glass transition temperature (Tg) of about 140 ° C. to 300 ° C. in order to improve the adhesion and heat resistance with the metal foil (a) layer. Preferably, it is about 180 to 280 ° C.

Moreover, in non-thermoplastic polyimide (B), it is preferable that Tg is 300 degreeC or more. Further, the linear expansion coefficient is preferably 20 × 10 ⁻⁶ / K or less, more preferably 5 × 10 ⁻⁶ / K or more and 18 × 10 ⁻⁶ / K or less, more preferably 10 × 10 ⁻⁶ / K or more and 16 × 10. ^-6 / K or less. By setting the linear expansion coefficient in the above range, dimensional stability and warpage can be improved.

  In the present invention, the thermoplastic polyimide (C) has a glass transition temperature (Tg) of preferably about 180 ° C. or lower, more preferably about 160 ° C. or lower. This is preferable because adhesion after thermocompression bonding is good. When the C layer-C layer is thermocompression bonded, the C layer formed on the metal foil (b) and the C layer formed on the non-thermoplastic polyimide layer (B) may have different compositions, In that case, if the Tg of at least one C layer is about 180 ° C. or less, even if the Tg of the other C layer is about 140 ° C. to 300 ° C., the thermocompression bonding is good, which is preferable.

  For the measurement of Tg and linear expansion coefficient, a conventionally used apparatus such as TMA (Thermomechanical Analysys) can be used. Specifically, a single-layer polyimide film having a width of 4 mm and a length of 20 mm is manufactured by Mac Science Corporation. It can be determined by setting to TMA-4000, raising the temperature from 25 ° C. to 500 ° C., and measuring the Tg and linear expansion coefficient.

  In the production method of the present invention, a method of applying a varnish containing a thermoplastic polyimide (A), a non-thermoplastic polyimide (B), a thermoplastic polyimide (C) and / or a precursor thereof onto a metal foil or a polyimide layer. The method is not particularly limited, and known methods such as a die coater, a comma coater, a roll coater, a gravure coater, a curtain coater, and a spray coater can be employed.

  About the method of thermocompression-bonding B layer-C layer or C layer-C layer, C layer-metal foil (b) layer, it is possible to apply pressure while maintaining the glass transition point temperature or higher of thermoplastic polyimide (C). A heat press method and / or a heat laminating method are given as typical examples. Although there is no restriction | limiting in particular as a laminating method, The method of pinching and sticking between a roll and a roll is preferable. The surface of the C layer and / or the B layer may be subjected to plasma treatment, corona discharge treatment, or the like.

  After laminating or while laminating, this metal-clad laminate is further heated and held at 150 to 500 ° C., so that B layer-C layer or C layer-C layer, C layer-metal foil (b) layer A polyimide metal laminate having excellent adhesion on the laminate surface can be obtained. As a heating device, a normal heating furnace, an autoclave, or the like can be used. As a heating atmosphere, air, inert gas (nitrogen, argon), or the like can be used. As the heating method, either a method of continuously heating or a method of leaving the polyimide metal laminate sheet in a heating furnace while being wound around a core is preferable. As the heating method, a conductive heating method, a radiant heating method, a combination method thereof, and the like are preferable. The heating time is preferably in the time range of 0.05 to 5000 minutes.

As a specific polyimide for each polyimide layer, the Tg of the thermoplastic polyimide (A) is preferably about 140 to 300 ° C., and the Tg of the thermoplastic polyimide (C) is preferably 180 ° C. In the case where the C layer-C layer is thermocompression bonded, the Tg of one C is preferably not limited as long as it is preferably about 180 ° C. or less, and the non-thermoplastic polyimide (B) Preferably, the Tg is not particularly limited as long as Tg is 300 ° C. or higher, and more preferably, the linear expansion coefficient is 20 × 10 ⁻⁶ / K or lower.

  Examples of usable A, B, and C include 1,3-bis (3-aminophenoxy) benzene (hereinafter abbreviated as APB) and 4,4′-bis (3-aminophenoxy) biphenyl as raw material diamines. (Hereinafter abbreviated as m-BP), 3,3′-diaminobenzophenone (hereinafter abbreviated as DABP), o-phenylenediamine, p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenyl ether, 3 It is preferable to contain at least one diamine selected from 4,4'-diaminodiphenyl ether and 3,3'-diaminodiphenyl ether, but it is not limited to these diamines.

  The raw acid dianhydride is not particularly limited, and a known acid dianhydride can be used, but 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (hereinafter abbreviated as BTDA). , Containing at least one acid dianhydride selected from pyromellitic dianhydride (hereinafter abbreviated as PMDA) and 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) However, it is not limited to these acid dianhydrides. Furthermore, in C, in order to lower Tg, the diamine represented by the general formula (2) is used as a raw material diamine,

(In the formula, n represents an integer of 1 to 3.)
It is also preferable that at least one diamine selected from diaminosiloxane compounds represented by the general formula (3) is included.

(Wherein R ₁ and R ₂ are a divalent aliphatic group or aromatic group having 1 to 4 carbon atoms, R _{3 to} R ₆ are a monovalent aliphatic group or aromatic group, and m is 1 to 1) Represents an integer of 20.)
Furthermore, the acid dianhydride preferably contains at least one acid dianhydride selected from tetracarboxylic dianhydrides represented by the general formula (4) in order to improve heat resistance.

  The reaction molar ratio of the diamine component and the tetracarboxylic dianhydride is usually in the range of 0.75 to 1.25. Preferably, when the diamine component is 1, the tetracarboxylic dianhydride is 0.8. It is in the range of -1.0.

  Furthermore, each polyimide A, B, and C formed by applying, drying and curing a varnish containing polyamic acid, which is a polyimide precursor, or a varnish obtained by mixing two or more kinds of varnish containing polyimide is also possible. is there. In the present invention, at least one of the polyimide layers is further represented by the following general formula (1).

(In the formula, m represents an integer of 0 or more, and Xs may be the same or different independently, and O, SO ₂ , S, CO, CH ₂ , C (CH ₃ ) ₂ , C ( CF ₃ ) ₂ or a direct bond, and R 1 is the same or different and represents a hydrogen atom, a halogen atom, or a hydrocarbon group, and the benzene ring substitution positions are independent of each other. It is preferable that it is a resin composition which mix | blends a maleimide compound, The thermoplastic polyimide and non-thermoplastic polyimide which are manufactured by mix | blending the said compound are also contained in the polyimide layer of this invention. By blending the above compound, it becomes possible to lower Tg, and particularly the adhesiveness after thermocompression bonding in the C layer becomes good. Furthermore, Tg can be increased depending on the heating and holding conditions after thermocompression bonding, and heat resistance, foam resistance, etc. can be improved.

In the general formula (1), m represents an integer of 0 or more, preferably 0 to 6, and more preferably 0 to 4. X may independently be the same or different and each represents X, O, SO ₂ , S, CO, CH ₂ , C (CH ₃ ) ₂ , C (CF ₃ ) ₂ or direct connection, O and C (CH ₃ ) ₂ are directly connected. R1 is the same or different and represents a hydrogen atom, a halogen atom, or a hydrocarbon group, and the substitution positions on the benzene ring are independent of each other. Preferably, the benzene ring is substituted at the ortho-position or meta-position.

  In the present invention, when the bismaleimide compound is used, the blending ratio to the polyimide is not particularly limited, but is preferably 0.1 to 70 with respect to the total weight of the polyamic acid which is a polyimide precursor. % By weight, more preferably 0.1 to 50% by weight. When the blending amount of the bismaleimide compound is within the above range, the heat resistance is improved and the adhesive strength with the metal foil is good. The blending method of the bismaleimide compound into the polyamic acid includes (a) a method of adding the bismaleimide compound to the polyamic acid solution, and (b) during polymerization of the polyamic acid, for example, a diamine compound or tetracarboxylic dianhydride. Examples thereof include, but are not limited to, a method of adding at the time of polymerization or in the middle of polymerization, and (c) a method of mixing a polyamic acid powder and a bismaleimide compound with solids.

  Further, after the polyamic acid is dehydrated and imidized into a polyimide solution in advance, a bismaleimide compound may be blended.

  The present invention makes it possible to thin the polyimide layer of the polyimide metal laminate without degrading the peel strength, dimensional stability, heat resistance, warpage, voids, etc. between the polyimide layer interface or the metal layer and the polyimide layer interface in the laminate lamination. It becomes possible to do.

Hereinafter, the present invention will be described in more detail with reference to examples.
In addition, about the glass transition point temperature (Tg) and linear expansion coefficient of the polyimide shown in the Examples, and the peel strength, void, warpage, dimensional stability (DS), and solder heat resistance of the polyimide metal laminated plate, the following methods are used. It was measured. For each measured value, the Tg and linear expansion coefficient of polyimide are shown in Table 1, and the values of the polyimide metal laminate are shown in Table 2, Table 3, and Table 4.

(1) Tg and linear expansion coefficient of polyimide A single layer polyimide film having a width of 4 mm and a length of 20 mm is set on TMA-4000 manufactured by Mac Science Co., Ltd., and the temperature is raised from 25 ° C. to 500 ° C., and measurement of Tg and linear expansion coefficient is performed. Was done. Here, the linear expansion coefficient was defined as an average linear expansion coefficient in a temperature range of 100 ° C. or higher and 150 ° C. or lower (Tg or lower).
For single-layer polyimide films, varnish is applied to a glass plate with an applicator so that the final thickness is 5 to 50 μm, heated from 110 ° C. to 240 ° C. at 9 ° C./min, dried, and cured imidized. The polyimide film was obtained by cooling and peeling in warm water.

(2) Peel strength (kN / m)
The obtained polyimide metal laminate was subjected to 90 ° peel measurement in accordance with JIS C-6471 (JIS C-6481).

(3) Void After etching and removing the metal foil on the C layer side of the polyimide metal laminate, the inside of the polyimide layer was observed from 500 to 2500 times with an optical microscope from the exposed polyimide surface. The occurrence of voids was confirmed.

(4) Warpage (mm)
A polyimide layer film obtained by etching away the metal foils on both sides of the polyimide metal laminate is cut out as a square sample of 50 mm square, and the convex side of the curved sample is placed on a flat surface such as a surface plate. The deformation amount of the four corners of the square sample was measured with reference to the board surface, and the average value of the deformation amount was taken as the value of warpage. In this case, the case of deformation so as to be convex toward the A layer side was a negative value, and the deformation on the opposite side was a positive value.

(5) Dimensional stability (DS)
The polyimide metal laminate was cut out as a sample of 300 mm × 300 mm square, and the sample length before and after the metal foil on both sides was removed by etching was measured to obtain vertical and horizontal sample size change rates.

(6) Solder heat resistance A polyimide metal laminate is cut out as a 20 mm square sample, left in an atmosphere of 30 ° C./85% RH for 48 hours, and then placed in a solder bath adjusted to each temperature of 200 ° C. to 400 ° C. It was immersed for 1 minute, and the lowest temperature at which trouble such as swelling occurred was measured.

Abbreviations for the solvents, acid dianhydrides, and diamines used in the examples are as follows.
DMAc: N, N-dimethylacetamide DABP: 3,3′-diaminobenzophenone APB: 1,3-bis (3-aminophenoxy) benzene APPB: 1,3-bis (3- (3-aminophenoxy) phenoxy) benzene pPD: p-phenylenediamine ODA: 4,4′-diaminodiphenyl ether m-BP: 4,4′-bis (3-aminophenoxy) biphenyl BTDA: 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride Product BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride PMDA: pyromellitic dianhydride APB-BMI: 1,3-bis (3-maleidophenoxy) benzene

Synthesis example 1
<Synthesis of precursor of thermoplastic polyimide (A) resin (A1 varnish)>
To a container equipped with a stirrer and a nitrogen introducing tube, 325.8 g of DMAc was added as a solvent, 23.2 g of DABP was added thereto, and the mixture was stirred at room temperature until dissolved. Thereafter, 34.3 g of BTDA is added to the diamine component so that the acid anhydride has a ratio of 0.975, and the mixture is stirred at 60 ° C. to obtain a polyamic acid solution having a polyamic acid content of 15% by weight. Obtained.

Synthesis Examples 3, 4, 5, 6, 7, 8
As shown in Table 1, B2, B3, C1, and C2 varnishes were obtained in the same manner as in Synthesis Example 1 except that the types and ratios of diamine, acid anhydride, and polyamic acid content were changed as shown in Table 1. It was. About C3, it stirred at room temperature until APB-BMI ratio added and melt | dissolved so that the APB-BMI ratio in solid content of C1 varnish might be 15%, and obtained C3 varnish as shown in Table 1.

Synthesis example 2
<Synthesis of Precursor of Non-thermoplastic Polyimide Resin (B1 Varnish)>
APB-BMI in the solid content of the varnish obtained by mixing the B2 varnish and the B3 varnish synthesized in Synthesis Example 3 and Synthesis Example 4 in a container equipped with a stirrer and a nitrogen introduction tube at a ratio of 7:93 APB-BMI was added so that the ratio was 5%, and the mixture was stirred at room temperature until dissolved to obtain B1 varnish (Table 1).

Example-1
A1 varnish of Synthesis Example 1 is dried on a polyimide laminated surface of a commercially available rolled copper foil (manufactured by Nikko Material Co., Ltd., trade name: BHY-22BT thickness 18 μm) with a roll coater so that the thickness after drying becomes 2.5 μm. After coating, it is dried at 150 ° C. for 0.5 minutes to form a thermoplastic polyimide (A) layer, and the B1 varnish of Synthesis Example 2 is dried on the surface of this A layer by a die coater so that the thickness after drying becomes 8 μm. After coating, the coating was dried at 135 ° C. for 1 minute to form a non-thermoplastic polyimide (B) layer. Further, the C1 varnish of Synthesis Example 5 was applied to the surface of this B layer with a roll coater so that the thickness after drying was 0.5 μm, and then dried at 110 ° C. for 0.5 minutes to be thermoplastic polyimide (C) A layer was formed. Thereafter, the temperature was increased from 110 ° C. to 380 ° C. at 9 ° C./min, dried, cured and imidized in a nitrogen atmosphere, and a polyimide metal having a polyimide (A, B, C) layer formed on the rolled copper foil. A laminate α was prepared.

  Next, after applying the C3 varnish of Synthesis Example 7 on the polyimide laminated surface of the rolled copper foil with a roll coater so that the thickness after drying becomes 2 μm, it is 9 ° C. from 110 ° C. to 240 ° C. in a nitrogen atmosphere. A polyimide metal laminate β having a polyimide (C) layer formed on a rolled copper foil was prepared by heating, drying, and curing imidization at / min.

Thereafter, the C layer of the polyimide metal laminate plate α and the C layer of the polyimide metal laminate plate β are bonded by thermocompression bonding at 260 ° C. under a pressure of 1.5 MPa with a roll laminator, and then in a batch type autoclave. Annealing was performed in a nitrogen atmosphere at a temperature of 300 ° C. for 4 hours to obtain a polyimide metal laminate shown in Table 2.
About the obtained polyimide metal laminated plate, peel strength (kN / m), void, warpage, dimensional stability, and solder heat resistance were measured and confirmed. The results are shown below.

Peel strength TPI-A side: 0.92 kN / m
Peel strength TPI-C side: 1.02 kN / m
Void: None Warpage: -0.5mm
Dimensional stability (DS): -0.010%
Solder heat resistance: occurrence of swelling at 320 ° C. (Table 2).

Examples-2, 3, 4, 5, 6, 7
In the same manner as in Example 1, except that the varnish for forming the A, B, and C layers and the layer thickness (layer thickness ratio) were changed as shown in Tables 2 and 3, Examples 2, 3, 4, 5, Tables 2 and 3 show the evaluations of the flexible metal laminates obtained in Steps 6 and 7.

Comparative Example-1
After applying the B1 varnish of Synthesis Example 2 to the surface of the stainless steel plate as a support with a die coater so that the thickness after drying is 8 μm, it is dried at 135 ° C. for 1 minute to form a non-thermoplastic polyimide (B) layer. Furthermore, after heating, drying, curing and imidization from 110 ° C. to 380 ° C. at 9 ° C./min in a nitrogen atmosphere, the non-thermoplastic polyimide (B) layer is peeled off from the stainless steel plate as the support. Thus, a non-thermoplastic polyimide (B) layer film was obtained. On one side of the obtained film, the A1 varnish of Synthesis Example 1 was applied by a roll coater so that the thickness after drying was 2.5 μm, and then dried at 150 ° C. for 0.5 minutes to be thermoplastic polyimide (A) A layer was formed, and on the opposite film surface, the C1 varnish of Synthesis Example 5 was applied with a roll coater so that the thickness after drying was 2.5 μm, and then dried at 150 ° C. for 0.5 minutes to be a thermoplastic polyimide. (C) A layer was formed. Thereafter, the temperature was increased from 110 ° C. to 250 ° C. at 9 ° C./min, dried, cured, and imidized in a nitrogen atmosphere to prepare a polyimide laminate in which polyimide (A, B, C) layers were formed. .

  Next, a commercially available rolled copper foil (manufactured by Nikko Materials Co., Ltd., trade name: BHY-22BT thickness 18 μm) is thermocompression-bonded on both sides of the polyimide laminate by a roll laminator at 260 ° C. under a pressure of 1.5 MPa. After that, annealing was performed in a batch type autoclave at a temperature of 300 ° C. for 4 hours in a nitrogen atmosphere, and polyimide metal laminates shown in Table 4 were obtained. About the obtained polyimide metal laminated plate, peel strength (kN / m), void, warpage, dimensional stability, and solder heat resistance were measured and confirmed. The results are shown below.

Peel strength TPI-A side: 0.20 kN / m
Peel strength TPI-C side: 0.20kN / m
Void: Yes Warpage: -8mm
Dimensional stability (DS): -0.060%
Solder heat resistance: 230 ° C. swelling occurred (Table 4). It is thought that the reason why each value was worse than in the examples was that the non-thermoplastic polyimide (B) layer film and the polyimide laminate were poorly transportable and could not be stably produced.

A polyimide metal laminate having a polyimide layer of 25 μm or less can be obtained without deteriorating the peel strength, dimensional stability, heat resistance, warpage, voids, etc. between polyimide layers or metal layers and polyimide layers, flexible wiring boards, etc. Widely applied to.

Claims (7)

Manufacture of a polyimide metal laminate comprising a metal foil (a) layer, a thermoplastic polyimide (A) layer, a non-thermoplastic polyimide (B) layer, a thermoplastic polyimide (C) layer, and a metal foil (b) layer in this order. In the method
Coating and forming a thermoplastic polyimide (A) layer and a non-thermoplastic polyimide (B) layer sequentially on the metal foil layer (a);
Gold Shokuhaku (b) layer, a thermoplastic polyimide (c1) layer is formed by coating, and the a non-thermoplastic polyimide (B) layer, a step of applying forming a thermoplastic polyimide (c2) layer;
A step of thermocompression bonding the thermoplastic polyimide (c1) layer and the thermoplastic polyimide (c2) layer to form a thermoplastic polyimide (C) layer,
At least one of the thermoplastic polyimide (c1) layer and a thermoplastic polyimide (c2) layer have a glass transition temperature of 180 ° C. or less, and the thermoplastic polyimide (c1) layer and the thermoplastic polyimide (c2) layer and Is a method for producing a polyimide metal laminate having a different composition .   2. The polyimide metal laminate according to claim 1, wherein the total thickness of the polyimide layer (the total thickness of the thermoplastic polyimide (A) layer, the non-thermoplastic polyimide (B) layer, and the thermoplastic polyimide (C) layer) is 25 μm or less. Manufacturing method. The thickness of the thermoplastic polyimide (A) layer is 0.1 to 5 μm, the thickness of the non-thermoplastic polyimide (B) layer is 1 to 24.8 μm, and the thickness of the thermoplastic polyimide (C) layer is 0.1 to 5 μm. 5 μm, and the ratio of the respective layer thicknesses is thermoplastic polyimide (A) layer: non-thermoplastic polyimide (B) layer: thermoplastic polyimide (C) layer = 1: 1.5: 0.3-1 : 248: 3 range,
The manufacturing method of the polyimide metal laminated sheet of Claim 1 or 2. 4. The method for producing a polyimide metal laminate according to claim 1, wherein the non-thermoplastic polyimide (B) has a linear expansion coefficient of 20 × 10 ⁻⁶ / K or less. The manufacturing method of the polyimide metal laminated board in any one of Claims 1-4 in which at least one layer of a polyimide layer mix | blends the bismaleimide compound represented by following General formula (1).

(In the formula, m represents an integer of 0 or more, and Xs may be the same or different from each other, and O, SO ₂ , S, CO, CH ₂ , C (CH ₃ ) ₂ , C ( CF ₃ ) ₂ or a direct bond, and R 1 are the same or different and each represents a hydrogen atom, a halogen atom, or a hydrocarbon group, and the benzene ring substitution positions are independent of each other. The raw material of the thermoplastic polyimide (C), the diamine component is at least one diamine compound selected from an aromatic diamine compound represented by the general formula (2) and / or a diaminosiloxane compound represented by the general formula (3) Including
The polyimide according to any one of claims 1 to 5, wherein the raw acid dianhydride component comprises at least one acid dianhydride selected from tetracarboxylic dianhydrides represented by the general formula (4). A method for producing a metal laminate.

(In the formula, n represents an integer of 1 to 3.)

(Wherein R ₁ and R ₂ are a divalent aliphatic group or aromatic group having 1 to 4 carbon atoms, R _{3 to} R ₆ are a monovalent aliphatic group or aromatic group, and m is 1 to 1) Represents an integer of 20.)

The glass transition temperature of one of the thermoplastic polyimide (c1) layer and the thermoplastic polyimide (c2) layer is 180 ° C or lower, and the other glass transition temperature is 140 to 300 ° C. 2. A method for producing a polyimide metal laminate according to 1 .