JP2001270035A - Flexible metal foil laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible metal foil laminate having a small dimensional stability even by sequentially treating an etching step and a heating step at the laminate obtained by laminating a polyimide and a metal foil. SOLUTION: The flexible metal foil laminate is obtained by laminating a heat press bondable polyimide film and the metal foil by a continuously laminating device to obtain a long-sized laminate, and then thermally annealing the laminate at 150 deg.C or higher or preferably 150 deg.C to a glass transition temperature of the bondable polyimide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible metal foil laminate, and more particularly, to a substrate material for forming a fine pitch circuit that has a small dimensional change even if sequential processes of an etching process and a heating process are added. It relates to a suitable flexible metal foil laminate.

[0002]

2. Description of the Related Art Aromatic polyimide films are widely used for electronic devices such as cameras, personal computers, and liquid crystal displays. In order to use an aromatic polyimide film as a substrate material for a flexible printed board (FPC) or a tape-automated bonding (TAB), a copper foil is laminated using an adhesive such as an epoxy resin. The method has been adopted.

It has been pointed out that aromatic polyimide films are excellent in heat resistance, mechanical strength, electrical properties and the like, but are inferior in properties of polyimide due to poor heat resistance of adhesives. To solve such a problem,
An all-polyimide substrate was developed in which copper was electroplated on a polyimide film without using an adhesive, a polyamic acid solution was applied to a copper foil, dried, imidized, or thermoplastic polyimide was thermocompressed. ing. But,
It has been pointed out that the metal foil laminate of all-polyimide obtained by these methods has problems such as low adhesive strength and impaired electrical characteristics.

Further, a polyimide laminate in which a polyimide adhesive is sandwiched between a polyimide film and a metal foil is known (US Pat. No. 4,432,432).
No. 95). However, this polyimide laminate has a problem that a biphenyltetracarboxylic acid-based polyimide film having a low linear thermal expansion has a low adhesive strength and cannot be used.

For this reason, in the roll laminating method, a method of using a metal having a specific hardness as a material of the laminating roll, or a method obtained by using a specific aromatic diamine as a thermocompression-bonding polyimide. The method used has been proposed. However, when a flexible metal foil laminate obtained by these methods is subjected to sequential processing of etching and heat treatment, the dimensional change rate of each step and the cumulative dimensional change rate of total become large, and the fine pitch of the electronic circuit becomes small. It has been difficult to satisfy the demand for chemical conversion.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a flexible metal foil laminate which is obtained by laminating a polyimide and a metal foil and has a small dimensional change even if sequential processing of an etching step and a heating step is added. That is.

[0007]

That is, the present invention provides:
After laminating the thermocompression bonding polyimide film and the metal foil by a continuous laminating apparatus to obtain a long laminate,
The present invention relates to a flexible metal foil laminate obtained by performing a thermal annealing treatment at a temperature of 0 ° C. or higher, preferably 150 ° C. or higher and lower than the glass transition temperature of the thermocompression-bondable polyimide. Further, the present invention provides a continuous laminating apparatus in which a thermocompression bonding polyimide film and a metal foil are laminated, and the dimensional change rate due to the sequential processing of the etching step and the heating step at room temperature is | ± 0.04. |% Or less and a cumulative dimensional change rate is | ± 0.07 |% or less. In the above description, | ± 0.
04 |% or less means that the absolute value is 0.04%, and | ± 0.07 |% means that the absolute value is 0.07%.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be listed below. 1) The above-mentioned flexible metal foil laminate, wherein the thermocompression-bondable polyimide film has a thermocompression-bondable aromatic polyimide layer on at least one surface, preferably both surfaces, of a highly heat-resistant aromatic polyimide layer. 2) The above flexible metal foil laminate, wherein the metal foil is an electrolytic copper foil, a rolled copper foil, an aluminum foil or a stainless steel foil. 3) The flexible metal foil laminate described above, wherein the metal foil is a metal foil having a thickness of 3 μm to 35 μm. 4) The flexible metal foil laminate described above, wherein the thermocompression-bondable polyimide film has a thickness of 7 to 50 μm.

5) A thermocompression-bondable polyimide film is formed by laminating a thermocompression-bondable aromatic polyimide layer on at least one surface, preferably both surfaces, of a highly heat-resistant aromatic polyimide layer by a coextrusion-cast film forming method. The flexible metal foil laminate obtained above. 6) Heat annealed sheet or rolled laminate
The flexible metal foil laminate obtained by subjecting the flexible metal foil laminate to a heat treatment.

The structure of the flexible metal foil laminate of the present invention includes, for example, the following combinations. In the following description, TPI-F indicates a thermocompression-bondable polyimide film. Metal foil / TPI-F Metal foil / TPI-F / Metal foil

In the present invention, a continuous laminate is used to laminate a thermocompression-bondable polyimide film and a metal foil to obtain a long laminate, which is then cut into single sheets or made of aluminum or stainless steel ( For example, it is necessary to perform a thermal annealing treatment at a temperature of 150 ° C. or higher, and preferably 150 ° C. or higher, for the laminated body which is wound around a core material such as SUS) and wound in a core.

The thermocompression-bondable polyimide film according to the present invention is preferably prepared, for example, after laminating a thermocompression-bondable aromatic polyimide precursor solution on one or both surfaces of a high heat-resistant aromatic polyimide precursor solution dried film. Is
A co-extrusion-cast film-forming method is used to laminate a thermocompression-bondable aromatic polyimide or a precursor solution thereof on one or both sides of a precursor solution of a high heat-resistant aromatic polyimide (also referred to as polyamic acid) solution, followed by drying and drying. It can be obtained by a method of obtaining a thermocompression-bondable multilayer polyimide film by imidization.

The high heat-resistant aromatic polyimide in the thermocompression-bondable multilayer polyimide film is preferably 3,
3 ′, 4,4′-biphenyltetracarboxylic dianhydride (hereinafter sometimes abbreviated simply as s-BPDA) and para-phenylenediamine (hereinafter sometimes simply abbreviated as PPD), and optionally further. It is produced from 4,4'-diaminodiphenyl ether (hereinafter sometimes simply referred to as DADE) and / or pyromellitic dianhydride (hereinafter sometimes simply referred to as PMDA). In this case, PPD / DADE (molar ratio) is 100/0
It is preferably ~ 85/15. Also, s-BPD
A / PMDA is preferably from 100: 0 to 50/50. The high heat-resistant aromatic polyimide is pyromellitic dianhydride and paraphenylenediamine and 4,
It is produced from 4'-diaminodiphenyl ether.
In this case, DADE / PPD (molar ratio) is 90/10 to 1
It is preferably 0/90. Furthermore, high heat-resistant aromatic polyimides include 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (BTDA) and pyromellitic dianhydride (PMDA) and paraphenylenediamine (PPD) and 4 , 4'-Diaminodiphenyle-
Manufactured from Ter (DADE). In this case, BTDA in the acid dianhydride is 20 to 90 mol%, and PMDA is 10 to 90 mol%.
80 mol%, PPD in diamine 30-90 mol%, D
Preferably, the ADE is from 10 to 70 mol%. Other types of aromatic tetracarboxylic dianhydrides and aromatic diamines such as 4,4'-diaminodiphenylmethane may be used as long as the physical properties of the high heat-resistant aromatic polyimide are not impaired. Further, a fluorine group on the aromatic ring of the aromatic tetracarboxylic dianhydride or the aromatic diamine,
A substituent such as a hydroxyl group, a methyl group or a methoxy group may be introduced.

As the high heat-resistant aromatic polyimide, those which cannot be confirmed at a temperature of less than about 350 ° C. in the case of a single-layer polyimide film are preferable. ~ 200 ° C) (M
D, TD and their average) are 5 × 10 ^-6
Those having a concentration of ２５25 × 10 ⁻⁶ cm / cm / ° C. are preferred.
In the synthesis of the aromatic polyimide having high heat resistance, if the proportion of each component is finally within the above range, random polymerization, block polymerization, blending, or synthesis of two or more kinds of polyamic acid solutions in advance and preparing each polyamic acid This can be achieved by any method of mixing an acid solution to obtain a copolymer by recombination of a polyamic acid.

As the thermocompression-bondable polyimide in the present invention, any thermoplastic polyimide which can be thermocompression-bonded at a temperature of about 300 to 400 ° C. may be used. Preferably 1,3-
Bis (4-aminophenoxybenzene) (hereinafter referred to as TPE
Sometimes abbreviated as R. ) And 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (hereinafter a-BPD)
Sometimes abbreviated as A. ) And manufactured from. Also,
As the thermocompression bonding polyimide, 1,3-bis (4
-Aminophenoxy) -2,2-dimethylpropane (D
ANPG) and 4,4'-oxydiphthalic dianhydride (O
DPA). Alternatively, it is produced from 4,4′-oxydiphthalic dianhydride (ODPA) and pyromellitic dianhydride and 1,3-bis (4-aminophenoxybenzene). Alternatively, 1,3-bis (3-aminophenoxy) benzene and 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride or 3,3′-diaminobenzophenone and 1,3-bis ( 3-aminophenoxy) benzene and 3,3 ', 4
It is prepared from 4'-benzophenonetetracarboxylic dianhydride.

Other tetracarboxylic dianhydrides, for example, 3, as long as the physical properties of the thermocompression-bondable polyimide are not impaired.
It may be replaced by 3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride or the like. Further, other diamines such as 4,4′-diaminodiphenyl ether, as long as the physical properties of the thermocompression-bondable polyimide are not impaired,
4,4'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, 2,2-bis (4-aminophenyl) propane, 1,4-bis (4-aminophenoxy)
Benzene, 4,4'-bis (4-aminophenyl) diphenyl ether, 4,4'-bis (4-aminophenyl) diphenylmethane, 4,4'-bis (4-aminophenoxy) diphenyl ether, 4,4'-bis (4-
Aminophenoxy) diphenylmethane, 2,2-bis [4- (aminophenoxy) phenyl] propane, 2,
Flexible aromatic diamine having a plurality of benzene rings such as 2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 1,4-diaminobutane,
6-diaminohexane, 1,8-diaminooctane,
Aliphatic diamines such as 1,10-diaminodecane and 1,12-diaminododecane, bis (3-aminopropyl)
It may be replaced by a diaminodisiloxane such as tetramethyldisiloxane. Dicarboxylic acids, such as phthalic acid and its substituted products, hexahydrophthalic acid and its substituted products, succinic acid and its substituted products and derivatives thereof, for blocking the amine end of the thermocompression-bondable aromatic polyimide In particular, phthalic acid may be used.

The above-mentioned thermocompression-bondable polyimide is prepared by mixing the above-mentioned components and, if necessary, other tetracarboxylic dianhydrides and other diamines in an organic solvent at a temperature of about 100 ° C. or less, especially 20 to 60 ° C. The solution is reacted at a temperature to form a polyamic acid solution, and this polyamic acid solution can be used as a dope solution. In order to obtain the thermocompression-bondable polyimide according to the present invention, the amount of the total moles of the acid (as the total moles of tetraacid dianhydride and dicarboxylic acid) in the organic solvent is based on the diamine (as the mole number). As a ratio,
Preferably 0.92 to 1.1, especially 0.98 to 1.1,
Among them, it is particularly 0.99 to 1.1, and the amount of the dicarboxylic acid used is preferably 0.00 to 0.1, particularly 0.0 as a ratio to the molar amount of the tetracarboxylic dianhydride.
A ratio such as 2 to 0.06 is preferred.

For the purpose of restricting the gelling of the polyamic acid, a phosphorus-based stabilizer such as triphenyl phosphite, triphenyl phosphate or the like is used in an amount of 0.01% based on the solid content (polymer) concentration during the polymerization of the polyamic acid. It can be added in the range of １1%. Further, for the purpose of accelerating imidization,
A basic organic compound-based catalyst can be added to the solution. For example, imidazole, 2-imidazole, 1,2
-Dimethylimidazole, 2-phenylimidazole, etc., in an amount of 0.01 to 20 with respect to the polyamic acid (solid content).
%, In particular from 0.5 to 10% by weight. Since these form a polyimide film at a relatively low temperature, they are used to avoid insufficient imidization. Further, for the purpose of stabilizing the adhesive strength, an organic aluminum compound, an inorganic aluminum compound or an organic tin compound may be added to the thermocompression-bondable aromatic polyimide raw material dope. For example, aluminum hydroxide, aluminum triacetylacetonate or the like can be added to the polyamic acid (solid content) at a ratio of 1 ppm or more, particularly 1 to 1000 ppm, as aluminum metal.

The organic solvent used for obtaining the above polyamic acid is N-methyl-2-pyrrolidone, N, N -Dimethylformamide,
N, N-dimethylacetamide, N, N-diethylacetamide, dimethylsulfoxide, hexamethylphosphoramide, N-methylcaprolactam, cresols and the like. These organic solvents may be used alone or in combination of two or more.

In the production of the above-mentioned thermocompression-bondable multilayer polyimide film, a co-extrusion-casting film forming method is preferably used, for example, by thermocompression bonding to one or both surfaces of a polyamic acid solution of the above-mentioned heat-resistant aromatic polyimide. A solution of an aromatic polyimide or a precursor thereof is co-extruded, and the solution is cast onto a support such as a mirror surface of a stainless steel, a belt surface or the like.
A method in which a semi-cured state or a dried state before that at about 200 ° C. can be adopted. When the cast film is processed at a high temperature exceeding 200 ° C., defects such as a decrease in adhesiveness tend to occur in the production of a thermocompression-bondable multilayer polyimide film. The semi-cured state or a state before that means that it is in a self-supporting state by heating and / or chemical imidization.

The co-extrusion of the polyamic acid solution giving the highly heat-resistant aromatic polyimide and the polyamic acid solution giving the thermocompression-bondable aromatic polyimide is described, for example, in Japanese Unexamined Patent Publication (Kokai) No. 3-180343 (JP-B-7-180343). 102661
JP-A No. 2000-216, and a co-extrusion method described in Japanese Patent Application Laid-Open Publication No. HEI 9-260, which is applied to a two- or three-layer extrusion die, and cast on a support. On one or both sides of the extrudate layer giving the high heat-resistant aromatic polyimide, a polyamic acid solution giving the thermocompression-bondable aromatic polyimide is laminated to form a multilayer film-like material, dried and then heat-pressed Is heated to a temperature not higher than the temperature at which deterioration occurs above the glass transition temperature (Tg) of the aromatic polyimide, preferably 300 to 500 ° C. (surface temperature measured by a surface thermometer) (preferably this temperature). Drying and imidizing to produce a thermocompression-bondable multilayer polyimide film having a thermocompression-bondable aromatic polyimide on one or both sides of a highly heat-resistant (substrate layer) aromatic polyimide. Can be.

The thermocompression-bondable aromatic polyimide according to the present invention has a glass transition temperature of 180 to 275 ° C., particularly 2 ° C. by using the above-mentioned acid component and diamine component.
100 to 275 ° C., preferably dried under the above conditions.
It is imidized and does not liquefy at a temperature in the range of 300 ° C. to 300 ° C., which is obtained by substantially not causing gelation of the thermocompression-bondable polyimide, and the elastic modulus is usually 275 ° C. When the modulus of elasticity is around room temperature (50
C.) are preferably about 0.0002 to 0.2 times the elastic modulus at (.degree. C.).

In the present invention, high heat resistance (substrate layer)
The thickness of the polyimide layer is 5 to 120 μm, especially 5 to 50 μm
m is preferable. If the thickness is less than 5 μm, there is a problem in mechanical strength and dimensional stability of the formed thermocompression-bondable multilayer polyimide film. On the other hand, when the thickness is more than 120 μm, there are difficulties in removing the solvent and imidizing. In the present invention, the thickness of the thermocompression bonding aromatic polyimide layer is 2 to 1 each.
0 μm, particularly preferably about 2 to 8 μm. If it is less than 2 μm, the adhesive performance is reduced, and if it exceeds 10 μm, it can be used, but there is no particular effect, but rather the heat resistance of the flexible metal foil laminate decreases. The thermocompression-bondable multilayer polyimide film has a thickness of 7 to 125 μm, particularly 7 to 50 μm.
It is preferred that If the thickness is less than 7 μm, it is difficult to handle the formed film. If the thickness is more than 125 μm, there are difficulties in removing the solvent and imidizing.

According to the coextrusion-casting film forming method, the high heat-resistant polyimide layer and the thermocompression-bondable polyimide on one or both sides thereof are cured at a relatively low temperature, and the thermocompression-bondable polyimide deteriorates. Thus, the imidization and drying of the self-supporting film can be completed, and a thermocompression-bonding multilayer polyimide film having good electrical properties and adhesive strength can be obtained.

Examples of the metal foil used in the present invention include various metal foils such as copper, aluminum, iron, gold and the like, and alloy foils of these metals. Preferably, rolled copper foil, electrolytic copper foil And so on. As the metal foil, those having a surface roughness not too large and not too small, preferably having an Rz of 7 μm or less, particularly Rz of 5 μm or less, particularly 0.5 to 5 μm are preferable. Such a metal foil, for example, a copper foil, is known as VLP, LP (or HTE). The thickness of the metal foil is not particularly limited.
It is preferably not more than μm, particularly preferably 3 to 35 μm. When Ra is small, a metal foil surface-treated may be used.

In the present invention, the thermocompression-bonding polyimide film and the metal foil are introduced into a continuous laminating apparatus such as a roll laminator or a double belt press, and preferably, in-line immediately before the laminating. 150-25
The laminate is preheated to about 0 ° C. and bonded by heating and pressing. In particular, the double belt press is capable of performing high-temperature heating and cooling under pressure, and is preferably a hydraulic type using a heat medium.

Further, the temperature of the heat compression zone of the roll laminate or double belt press is higher than the glass transition temperature of the thermocompression-bondable polyimide by 20 ° C. or more and 400 ° C. or lower, especially 30 ° C. or higher than the glass transition temperature. Thermocompression bonding under pressure at a high temperature of 400 ° C. or less, especially in the case of a double belt press, followed by cooling under pressure with a cooling zone,
Preferably, the glass transition temperature of the thermocompression bonding polyimide is 20 or more.
It is preferable to obtain a laminate by cooling to a temperature lower by at least 30 ° C., in particular, a temperature lower by at least 30 ° C. In the above method, when the product is a single-sided metal foil flexible metal foil laminate, a highly heat-resistant film easily peelable, for example, a high heat-resistant film or a metal foil having the Rz of less than 2 μm,
Preferably, a high heat-resistant resin film such as a polyimide film (Ube Industries, Ltd., UPILEX S) or a fluororesin film, or a rolled copper foil is used to protect a metal foil having a small surface roughness and good surface smoothness. As a material, it may be interposed between the thermocompression-bondable polyimide layer and another metal surface. After lamination, this protective material may be removed from the laminate and rolled up, or may be rolled up with the protective material laminated and removed at the time of use.

In particular, by laminating by thermocompression bonding and cooling under pressure using a double belt press, a long, wide, about 400 mm or more, particularly about 500 mm or more wide, high adhesive strength (90 ° pin) is obtained. -Lead strength: 0.7 kg / cm
As described above, in particular, 1 kg / cm or more), it is possible to obtain a flexible metal foil laminate having a good appearance such that wrinkles are not substantially observed on the surface of the metal foil.

In the present invention, the flexible metal foil laminate is formed by laminating the thermocompression-bondable multilayer polyimide film and the metal foil in a rolled state by a continuous laminating apparatus such as a roll laminator or a double belt press. And
The laminated body in the core wound state is formed into a long laminated body in a rolled state and cut into single sheets, or re-wound around a core material such as aluminum or stainless steel (SUS).
It is necessary to perform a thermal annealing treatment at a temperature of at least 150 ° C., preferably at a temperature of at least 150 ° C. and lower than the glass transition temperature of the thermocompression-bondable polyimide. When the temperature is lower than 150 ° C., a sequential processing of etching and heat treatment is applied to increase the dimensional change rate in any one of the steps or the cumulative dimensional change rate of the total, thereby increasing the excellent flexible metal foil laminate. Will be difficult to obtain.

According to the present invention, the dimensional change rate after etching at room temperature and the dimensional change rate after heat treatment at 250 ° C. for 30 minutes are obtained by subjecting the laminated body laminated by the continuous laminating apparatus to a thermal annealing treatment. Is | ± 0.04
|% Or less, preferably ± 0.01 to ± 0.04, and the cumulative dimensional change rate, which is the sum of the dimensional change rate after etching at room temperature and the dimensional change rate after heat treatment at 250 ° C. for 30 minutes, is | |
± 0.07 |% or less, preferably ± 0.001 to ± 0.0
7 can be obtained. If any of the respective dimensional change rates and the cumulative dimensional change rate of the flexible metal foil laminate is out of the range, it is difficult to apply the fine pitch to an electronic circuit.

The flexible metal foil laminate obtained according to the present invention may be cut to a predetermined size if necessary, or may be subjected to various treatments such as roll winding, etching and, if necessary, curling back. Thus, it can be used as a substrate for electronic components. For example, FPC, TAB, multilayer F
It can be suitably used as a substrate for a PC or a flex-rigid substrate. In particular, the thickness of the metal foil is 3 to 35 μm
And the thickness of the thermocompression-bonding multilayer polyimide film layer is 7 to 50
μm single-sided copper foil laminate (having a total thickness of 15 to 85 μm).
m) or double-sided copper foil laminate (total thickness of 25 to 120)
μm), a heat-resistant adhesive (thickness of 5 to 50 μm, preferably 5 to 15 μm, selected from an epoxy-based adhesive or a heat-resistant polyimide-based adhesive such as a thermoplastic polyimide, a thermoplastic polyamide-imide, or a polyimidesiloxane-epoxy-based adhesive. In particular, by bonding a plurality of copper foil laminates using 7 to 12 μm),
With 0 layers, a multilayer substrate that satisfies high heat resistance, low water absorption, low dielectric constant, and high electrical characteristics can be suitably obtained. The flexible metal foil laminate of the present invention includes not only a long one but also a long one cut into a predetermined size as described above.

The flexible metal foil laminate of the present invention is used as a circuit board by performing a sequential processing of an etching step and a heating step known per se. Examples of the etching step include a method of etching a metal foil such as a copper foil of a flexible metal foil laminate at room temperature with an etching solution such as an aqueous ferric chloride solution. The heating step may be, for example, a soldering process in which the flexible metal foil laminate is immersed in a solder bath at 280 ° C. for about 10 seconds, or a laminate with another flexible metal foil laminate using a heat-resistant adhesive to form a multilayer substrate. Heat and pressure bonding.

[0033]

The present invention will be described in more detail with reference to the following examples. In each of the following examples, physical properties were evaluated according to the following methods. Heat shrinkage: 30 before heat treatment of polyimide film
The dimensional change after the heat treatment at 0 ° C. for 2 hours was determined and expressed in%. Dimensional change after etching: Dimensional change before and after room-temperature etching (43 ° C., etching agent: ferric chloride aqueous solution) of the flexible metal foil laminate was determined and expressed in%. Cumulative dimensional change after heat treatment: After etching, heat treatment was further performed at 250 ° C. for 30 minutes to obtain a dimensional change from before etching, and the result was expressed in%. Dimensional change rate due to heat treatment: Dimensional change rate obtained by subtracting dimensional change rate due to etching () from cumulative dimensional change rate after heat treatment () Thermal expansion coefficient: Measured at 50 to 200 ° C., 5 ° C./min (T
D, average value of MD), cm / cm / ° C Glass transition temperature (Tg): Measured from viscoelasticity. Adhesive strength: Measure 90 ° peel strength and evaluate with average value Electrical properties: Measure volume resistance by ASTM D257 Overall evaluation: ○: Small dimensional change, adhesive strength with 90 ° peel strength of 1.0 kgf / cm or more Large, good electrical characteristics, good appearance, Δ: slightly large dimensional change, normal ×, large: large dimensional change, poor

Synthesis Example 1 of Dope for Production of Highly Heat-Resistant Aromatic Polyimide A reaction vessel equipped with a stirrer and a nitrogen inlet tube was charged with N-methyl-
2-Pyrrolidone was added, and further, paraphenylenediamine and 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride in a molar ratio of 1000: 998? To give a monomer concentration of 18% (% by weight, the same applies hereinafter).
After completion of the addition, the reaction was continued for 3 hours while maintaining the temperature at 50 ° C. The resulting polyamic acid solution is a brown viscous liquid,
The solution viscosity at ℃ was about 1500 poise. This solution was used as a dope.

Synthesis of Dope for Production of Aromatic Polyimide of Thermocompression Bonding-1 N-Methyl-methyl was added to a reaction vessel equipped with a stirrer and a nitrogen inlet tube.
2-Pyrrolidone was added, and 1,3-bis (4-aminophenoxy) benzene and 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride were further added at 1000: 100.
At a molar ratio of 0, the monomer concentration is 22% and triphenyl phosphate is added at a ratio of 0.2 to the monomer weight.
1% was added. After completion of the addition, the reaction was continued for 1 hour while maintaining the temperature at 25 ° C. This polyamic acid solution had a solution viscosity of about 2000 poise at 25 ° C. Dosing this solution
Used as a loop.

REFERENCE EXAMPLE 1 A three-layer extrusion die (multi-manifold die) was provided with the above-mentioned heat-resistant aromatic polyimide dope and the thermocompression-bondable aromatic polyimide dope. Using a film forming apparatus, the film was cast on a metal support and dried continuously with hot air at 140 ° C. to form a solidified film. After the solidified film was peeled from the support, the temperature was gradually raised from 200 ° C. to 320 ° C. in a heating furnace to remove the solvent and imidize, and the three-layer extruded polyimide film was wound up on a roll. . The obtained three-layer extruded polyimide film exhibited the following physical properties.

1) Thermocompression-bondable multilayer polyimide film-1 Thickness composition: 4 μm / 17 μm / 4 μm (total 25 μm) Tg of thermocompression-bondable aromatic polyimide: 250 ° C. Volume resistance> 1 × 10 ¹⁵ Ω · cm Functional polyimide film has a coefficient of linear thermal expansion (50-200 ° C.) of 10 × 10 ^{−6 to} 25 × 10 ⁻⁶ × c
m / cm / ° C.

Comparative Example 1 The above thermocompression-bondable multilayer polyimide film-1 and two rolled electrolytic copper foils (3EC-Mitsui Metal Mining Co., Ltd.)
VLP, Rz 3.8 μm, thickness 18 μm) are continuously supplied to the double belt press, and after preheating, the temperature of the heating zone (maximum heating temperature) 380 ° C. (setting), the cooling zone Temperature (minimum cooling temperature: 117 ° C.), thermocompression bonding under continuous pressure-cooling, cooling and lamination to form a laminate (width: about 530 m)
m, the same applies hereinafter). The evaluation results of the obtained laminate are shown below. Dimensional change after etching: -0.01% Cumulative dimensional change after heat treatment: -0.11 Dimensional change by heat treatment: -0.10% Overall evaluation: ×

COMPARATIVE EXAMPLE 2 The roll-shaped laminate obtained in Comparative Example 1 was cut into single sheets and heat-treated at 100 ° C. for 60 minutes in an inert oven to obtain a flexible metal foil laminate. I got The evaluation results of the obtained flexible copper foil laminate are shown below. Dimensional change after etching: -0.01% Cumulative dimensional change after heat treatment: -0.10 Dimensional change by heat treatment: -0.09% Overall evaluation: ×

Example 1 The roll-shaped laminate obtained in Comparative Example 1 was cut into sheets and heated in an inert oven at 200 ° C. for 60 minutes to perform a thermal annealing treatment. Thus, a flexible metal foil laminate was obtained. The evaluation results of the obtained flexible copper foil laminate are shown below. Dimensional change after etching: -0.02% Cumulative dimensional change after heat treatment: -0.06 Dimensional change by heat treatment: -0.04% Overall evaluation: ○

Example 2 The roll-shaped laminate obtained in Comparative Example 1 was cut into sheets and heated in an inert oven at 300 ° C. for 60 minutes to perform a thermal annealing treatment. Thus, a flexible metal foil laminate was obtained. The evaluation results of the obtained flexible copper foil laminate are shown below. Dimensional change after etching: -0.03% Cumulative dimensional change after heat treatment: -0.04 Dimensional change by heat treatment: -0.01% Overall evaluation: ○

Example 3 A core wound material obtained by rewinding the roll-shaped laminate obtained in Comparative Example 1 around an aluminum core material was heated at 260 ° C. for 60 minutes in an inert oven. An annealing treatment was performed to obtain a flexible metal foil laminate. The evaluation results of the obtained flexible copper foil laminate are shown below. Dimensional change after etching: -0.02% Cumulative dimensional change after heat treatment: -0.05 Dimensional change by heat treatment: -0.03% Overall evaluation: ○

Example 4 A core wound material obtained by rewinding the roll-shaped laminate obtained in Comparative Example 1 around a SUS core material was placed in an inert oven.
Heating treatment was performed at 60 ° C. for 60 minutes to obtain a flexible metal foil laminate. The evaluation results of the obtained flexible copper foil laminate are shown below. Dimensional change after etching: -0.03% Cumulative dimensional change after heat treatment: -0.06 Dimensional change by heat treatment: -0.03% Overall evaluation: ○

Examples 5 to 6 Thermocompression-bondable multilayer polyimide film-1 and thickness 12 μm
m or an electrolytic copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd.) or a thermocompression-bonding multilayer polyimide film-1 and a 9 μm-thick electrolytic copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd.). To form a roll-shaped laminated body, and then a core wound (core material: aluminum), and subjected to a thermal annealing treatment.
A flexible metal foil laminate was obtained. The evaluation results of the obtained flexible copper foil laminate were all the same as in Example 3 and showed good results.

[0045]

According to the present invention, the following effects can be obtained because of the above configuration.

According to the present invention, it is possible to obtain a flexible metal foil laminate having good dimensional stability even if sequential processes of an etching step and a heating step are added, regardless of the properties of the thermocompression bonding polyimide film as a raw material. Thus, a substrate material for forming a fine pitch circuit can be provided.

Continued on front page F-term (reference) 4F100 AB01B AB04B AB10B AB17B AB33B AK49A AK49C BA02 BA03 BA04 BA07 BA10B BA10C BA13 EA02 EH20 EJ41 EJ64 GB43 JA20A JA20B JJ03C JL04 JL12A YY00 YY00A YY00B

Claims (8)

[Claims] 1. A continuous laminating apparatus for laminating a thermocompression-bondable polyimide film and a metal foil to obtain a long laminated body, and then performing a thermal annealing treatment at a temperature of 150 ° C. or more. Flexible metal foil laminate. 2. The flexible metal foil according to claim 1, wherein the thermocompression-bondable polyimide film has a thermocompression-bondable aromatic polyimide layer on at least one side, preferably both sides, of a high heat-resistant aromatic polyimide layer. Laminate. 3. The flexible metal foil laminate according to claim 1, wherein the metal foil is an electrolytic copper foil, a rolled copper foil, an aluminum foil, or a stainless steel foil. 4. The flexible metal foil laminate according to claim 1, wherein the metal foil is a metal foil having a thickness of 3 μm to 35 μm. 5. The thermocompression-bondable polyimide film has a thickness of 7 to 7.
The flexible metal foil laminate according to any one of claims 1 to 3, which has a thickness of 50 µm. 6. A thermocompression-bondable polyimide film is formed by laminating and integrating a thermocompression-bondable aromatic polyimide layer on at least one surface, preferably both surfaces, of a highly heat-resistant aromatic polyimide layer by a coextrusion-cast film forming method. The flexible metal foil laminate according to any one of claims 1 to 5, which is obtained by: 7. The flexible metal foil laminate according to any one of claims 1 to 6, wherein the single-piece or rolled laminate is subjected to a thermal annealing treatment. 8. The rate of dimensional change due to sequential processing of an etching step and a heating step at room temperature, wherein a thermocompression bonding polyimide film and a metal foil are laminated by a continuous laminating apparatus, is | -0.04 |. % Or less, and the cumulative dimensional change rate is | -0.07 |% or less.