JP2002114848A - New thermoplastic polyimide resin and flexible metal foil-clad laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper-clad laminate especially excellent in resistance to soldering heat after moisturized. SOLUTION: This flexible metal foil-clad laminate is formed by thermally laminating a heat-resistant bond ply having a thermoplastic polymide layer and a layer or metal foil on one or both of the surfaces of a heat-resistant base film, wherein the thermoplastic polyimide does not become cloudy nor the thermoplastic polyimide is released from the metal foil, when subjected to solder-dipping test at 280 deg.C for 10 sec after moisturized at 40 deg.C in 90 RH% for 96 hr. The copper-clad laminate having excellent adhesiveness and excellent resistance to soldering heat is realized by using a main acid component comprising hydroquinone bis(anhydrotrimellitic acid) ester monomer (TMHQ) as the thermoplastic polyimde layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pliable laminate comprising a bond ply having a thermoplastic polyimide layer on at least one surface of a base film and a thin metal sheet, a thermoplastic polyimide resin suitably usable for the same, and Regarding the manufacturing method of the laminate, more specifically, 40 ° C.
90% moisture absorption 96 hours after treatment, no turbidity of the thermoplastic polyimide layer and no peeling between the thermoplastic polyimide layer and the metal layer in the solder bath dip test at 280 ° C. for 10 seconds. The present invention relates to a flexible laminate comprising a bond ply having a thermoplastic polyimide layer and a thin metal sheet.

[0002]

2. Description of the Related Art In recent years, higher performance and higher functionality of electronic devices have been developed.
The miniaturization is rapidly progressing, and there is an increasing demand for miniaturization and weight reduction of electronic components used in electronic devices. Along with this, the heat resistance, mechanical strength,
Various physical properties such as electrical characteristics are further required, and a higher density, higher function, and higher performance are also required for a semiconductor element packaging method and a wiring board for mounting the same. With regard to flexible printed wiring boards (hereinafter referred to as FPC), fine wire processing, multilayer formation, etc. are performed, and component mounting FPs in which components are mounted directly on the FPC.
C, a double-sided FPC in which a circuit is formed on both sides, a multilayer FPC in which a plurality of FPCs are stacked, and the layers are connected by wiring have appeared.

Generally, an FPC has a structure in which a circuit pattern is formed on a flexible and thin base film, and a surface cover layer is provided. In order to obtain the above-mentioned FPC, an insulating adhesive used as a material thereof is used. And the performance of insulating organic films must be improved. Specifically, it has high heat resistance and mechanical strength, and is excellent in workability, adhesiveness, low hygroscopicity, electrical characteristics, and dimensional stability.

At present, a film made of a polyimide resin having excellent characteristics is widely used as an insulating organic film for FPC. An epoxy resin or an acrylic resin that is excellent in low-temperature workability and workability is used as the insulating adhesive. However, it has been found that these adhesives are not particularly satisfactory in heat resistance. More specifically, when exposed to a temperature of 150 ° C. or more for a long time, these adhesives are deteriorated, which affects various characteristics. Furthermore, when using these adhesives, the adhesive is applied on a base film, dried, and then adhered to a conductor layer (generally, copper foil is used). Have to be heat-treated.

[0005] In particular, with the expanding use of FPCs, there is an urgent need to solve the problem of heat resistance. In order to solve this problem, a two-layer FPC having no adhesive layer and an FPC using a polyimide resin having excellent melt fluidity have been proposed. Regarding the two-layer FPC having no adhesive layer, a method in which a conductor layer is formed directly on an insulating film and a method in which an insulating layer is formed directly on a conductor layer are common. In the method of forming a conductor layer directly on an insulating layer, a method is used in which a thin layer of a conductor is formed by vapor deposition or sputtering, and then a thick layer of the conductor is formed by plating. There are problems that holes are easily generated and it is difficult to obtain a sufficient adhesive force between the insulating layer and the conductor layer.

On the other hand, in a method of forming an insulating layer directly on a conductor layer, a method of casting and drying a solution of a polyimide copolymer or a polyamic acid copolymer on the conductor layer and drying the same is used. In addition, the conductor layer is likely to be corroded by various solvents. Further, when a double-sided plate is manufactured, there is a problem that a complicated process is required such that two single-sided plates are manufactured and then these single-sided plates are adhered to each other.

[0007] FPCs using a polyimide resin having excellent melt fluidity are disclosed in Japanese Patent Application Laid-Open Nos.
No. 179224 or a bonding sheet having a thermoplastic polyimide layer on at least one surface of a base film made of a heat-resistant resin proposed in JP-A-5112768,
It has been difficult to realize excellent soldering heat resistance after moisture absorption under increasingly severe use environment conditions in the future.

[0008]

As described above, the FPC having excellent heat resistance has problems in any form, but in consideration of productivity and characteristics, a base film made of a heat-resistant resin is required. It is considered that the most advantageous method is to bond a thin metal sheet such as a copper foil with a bond ply obtained by laminating a thermoplastic polyimide. Therefore, the above-mentioned problem relating to this case, that is, a heat-resistant flexible thin metal sheet laminate manufactured from a heat-resistant bond ply suitable for FPC applications showing excellent solder heat resistance even after moisture absorption treatment, As a result of intensive studies aimed at providing a thermoplastic polyimide useful as an adhesive for a bond ply and an adhesive obtained therefrom, the present invention has been achieved.

[0009]

SUMMARY OF THE INVENTION The present invention has the following constitution, thereby achieving the above object. 1) A polyimide resin obtained from a precursor of a polyimide resin, wherein the precursor has a general formula (Formula 23)

[0010]

Embedded image (In the formula, k is an integer of 1 or more, m and n are each an integer of 0 or more where m + n is 1 or more. A and B are the same or different tetravalent organic groups, X and Y each represent a divalent organic group which may be the same or different.)
2) More than 50 mol% of A and B in the following formula (Formula 24)

[0011]

Embedded image A thermoplastic polyimide resin having a tetravalent organic group shown in (1). 2) X and Y in the general formula (Formula 23) are represented by the following formula (Formula 2)
5)-(Formula 44)

[0012]

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[0013]

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[0014]

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[0015]

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[0016]

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[0017]

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[0018]

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[0019]

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[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

Embedded image The thermoplastic polyimide resin according to 1), which is at least one selected from the group of divalent organic groups shown in (1). 3) A heat-resistant bond ply in which an adhesive layer containing the thermoplastic polyimide resin described in 1) or 2) is formed on one or both surfaces of a heat-resistant base film. 4) The heat-resistant bond ply according to 3), wherein the base film of the heat-resistant bond ply is a non-thermoplastic polyimide film. 5) A heat-resistant flexible metal foil-clad laminate obtained by thermally laminating the heat-resistant bond ply according to 3) or 4) and a thin metal sheet. 6) The heat-resistant flexible thin metal sheet-clad laminate according to 5), wherein the thin metal sheet is selected from a copper foil and an aluminum foil. 7) The adhesive for a heat-resistant flexible metal foil-clad laminate according to claim 1 or 2. 8) 260 ° C after treatment at 40 ° C, 90RH%, 192 hours
When a solder bath dip test is performed at 60 ° C. for 60 seconds, no turbidity of the thermoplastic polyimide layer and no peeling between the thermoplastic polyimide layer and the metal layer of the foil layer occur.
Or a heat-resistant flexible metal foil-clad laminate excellent in moisture-absorbing solder heat resistance according to 6).

[0032]

Embodiments of the present invention will be described below. First, a method for preparing a polyamic acid copolymer solution which is a precursor of the thermoplastic polyimide in the present invention will be described.

The polyamic acid copolymer can be obtained by reacting an acid dianhydride with a diamine in an organic solvent. According to the present invention, first, in an atmosphere of an inert gas such as argon or nitrogen, general Formula (Formula 45)

[0034]

Embedded image (In the formula, C represents a tetravalent organic group.) At least one acid dianhydride is dissolved or diffused in an organic solvent. The solution has the general formula

[0035]

Embedded image (In the formula, X represents a divalent organic group.) At least one kind of diamine is added in a solid state or an organic solvent solution state. Furthermore, a mixture of one or more acid dianhydrides represented by the above general formula (Chemical Formula 11) is added in a solid state or an organic solvent solution, and a polyamic acid solution as a polyimide precursor is added. Get. In this reaction, contrary to the above addition procedure, a diamine solution may be prepared first, and a solid acid dianhydride or an organic solvent solution of acid dianhydride may be added to the solution. The reaction temperature at this time is preferably from 10C to 0C. The reaction time is 30 minutes to 3 hours. By this reaction, a polyamic acid solution which is a precursor of the thermoplastic polyimide is prepared.

Examples of the organic solvent used in the synthesis reaction of the polyamic acid include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N dimethylformamide and N, N diethylformamide, and N, N dimethyl Acetamide solvents such as acetamide and N, N diethylacetamide can be mentioned. These may be used alone or in combination of two or more. Further, a mixed solvent composed of these polar solvents and a non-solvent of polyamic acid can also be used. Examples of the non-solvent for the polyamic acid include acetone, methanol, ethanol, isopropanol, benzene, and methyl cellosolve.

The molecular weight of the polyamic acid copolymer and the polyimide copolymer is not particularly limited, but in order to maintain the strength as a heat-resistant adhesive, the number average molecular weight is 50,000 or more, and It is preferably at least 80,000, particularly preferably at least 100,000. The molecular weight of the polyamic acid copolymer (solution) as an adhesive can be measured by GPC (gel permeation chromatography).

Next, as a method of obtaining a polyimide from these polyamic acids, a method of thermally or chemically dehydrating a ring closure (imidization) may be used. Specifically, the method of thermally dehydrating ring closure (imidization) includes heating and drying under normal pressure or heating and drying a polyamic acid solution under reduced pressure.

When heating and drying at normal pressure, first, the organic solvent is evaporated at a temperature of 150 ° C. or less for about 5 minutes to 9 hours to evaporate the organic solvent.
It is preferably performed for 0 minutes. Subsequently, this is dried by heating to imidize it. Heating temperature for imidization is 150 ° C
The range of -400 ° C is preferred. Especially the final heat treatment is 30
0 ° C. or higher is preferred. More preferably 300 to 400
C is preferred.

When heating and drying under reduced pressure, solvent removal and imidization are performed simultaneously. The heating temperature is 150 ° C
The range of -200 ° C is preferred. In this method, since heating is performed under reduced pressure, water is easily removed from the system. Therefore, it is characterized in that the hydrolysis of the imide ring and the accompanying decrease in the molecular weight are less likely to occur as compared with the heating under normal pressure.

In the method of chemically dehydrating ring closure (imidization), a dehydrating agent having a stoichiometric amount or more and a tertiary amine as a catalyst are added to the above-mentioned polyamic acid solution, and the dehydration is performed in the same manner as in the thermal dehydration. Upon treatment, a desired polyimide film can be obtained in a shorter time than when thermally dehydrating.

As the tertiary amine used as a catalyst, pyridine, α-picoline, β-picoline, γ-picoline, trimethylamine, triethylamine, isoquinoline and the like are preferable.

Examples of the organic solvent for dissolving the obtained polyimide resin include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N dimethylformamide and N, N diethylformamide, and N, N dimethylacetamide. Acetamide solvents such as N, N diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone, tetrahydrofuran,
Examples thereof include ether solvents such as 1,4-dioxane and dioxolan. These may be used alone or in combination of two or more.

Next, the base film of the present invention will be described. The base film is preferably a non-thermoplastic polyimide, and specific examples include Apical AH, NPI, and HP (all of which are Kanebuchi Chemical Industries).

In addition, polyimides obtained from various combinations of acid dianhydrides and diamines can be used according to required characteristics.

The thin metal sheet of the present invention has a thickness of 20 to 20.
Those having a thickness of 200 μm are preferred.

Specific examples of the thin metal sheet include copper foil,
Aluminum foil is preferably used.

[0048] This base film is coated with the thermoplastic
Commonly used in the industry as imide solution or its precursor
Apply the known amic acid to the desired configuration of the bond
You can get plies. Same with thin metal sheet
If you can easily envision technically if you are a trader
Heat and pressure laminating system that can process any kind of continuously
Select a heat-resistant flexible thin metal sheet laminate
You can get it.

Although the embodiment of the heat-resistant flexible metal foil laminate according to the present invention has been described above, the present invention is not limited to this, and the present invention is not limited to the spirit and scope of those skilled in the art without departing from the spirit thereof. Based on the knowledge, various improvements, changes, and modifications can be made. The present invention will be described more specifically with reference to the above examples, but the present invention is not limited to these examples.

[0050]

Example 1 The whole system was cooled with ice water and purged with nitrogen.
100 g of 2,2 'in a 000 ml three-neck separable flask
Bis [4- (4-aminophenoxy) phenyl] propane (hereinafter, referred to as BAPP) was charged with 708.4 g of dimethylformamide (hereinafter, referred to as DMF) and sufficiently dissolved. After stirring for 15 minutes, 108.2 g of p-phenylenebis (trimellitic acid monoester anhydride) monomer (hereinafter referred to as TMHQ) was charged as a powder. After stirring for 30 minutes, 3.4 g of TMHQ was further slurried with 8.4 g of DMF, and gradually added while paying attention to the viscosity of the solution in the flask.
% Polyamic acid was obtained. Thereafter, 1296 g of DMF was added and stirred for 1 hour to adjust the viscosity to about 5 poise.

This polyamic acid solution was applied on both sides of a polyimide film (Apical 17HP; manufactured by Kaneka Chemical Industry Co., Ltd.) so that the final one-sided thickness of the thermoplastic polyimide layer was 4 μm, and then applied at 120 ° C. and 350 ° C. The solvent was removed by heating for 2 minutes each to obtain a bond ply. A rolled copper foil having a thickness of 18 μm is laminated on the thermoplastic polyimide surface of the obtained bond ply, and a 125 μm-thick polyimide film is disposed as a release film on the upper and lower sides of the roll, and laminated with a hot roll to obtain a copper-clad laminate. .

The laminating temperature is 360 ° C. and the pressure is 30 kg.
/ Cm, and the roll rotation speed was 1 m / min. For the obtained copper-clad laminate, according to JIS C6481, adhesive strength,
A solder heat resistance test was performed in accordance with JIS6471 to observe whether the copper layer and the thermoplastic polyimide layer of the test piece were peeled off, and etched the copper layer to confirm the presence or absence of cloudiness in the thermoplastic polyimide layer. Table 1 shows the results. The test conditions were as follows: 40 ° C., 90% RH, after absorbing moisture for 96 hours, 280
C. Dipped for 10 seconds. Glass transition temperature (T
g) was measured by a viscoelasticity measuring device. Table 1 shows the results.

[0053]

Example 2 100 g of BAPP was sufficiently dissolved in 704.7 g of DMF. After stirring for 15 minutes, 100.5 g of TM
HQ and 7 g of 3,3′4,4′-ethylene glycol dibenzoate tetracarboxylic dianhydride (hereinafter referred to as TMEG) were charged as powder. After stirring for 30 minutes, an additional 3.0 g of TME
A solution in which G was dissolved in 7.0 g of DMF was gradually added while paying attention to the viscosity in the flask, and then left for 1 hour with stirring. Thereafter, 1190 g of DMF was charged and stirred for 1 hour to obtain a polyamic acid solution. This polyamic acid solution was applied to a base film in the same manner as in Example 1;
Drying was performed at 350 ° C. for 2 minutes to obtain a bond ply.
Thereafter, CCL production and physical property measurement were performed in the same manner as in Example 1 under the conditions of 360 ° C., 30 kgf / cm, and 1 m / min. Table 1 shows the results.

[0054]

Comparative Example 1 1 g of BAPP was dissolved in 607 g of DMF,
33.2 g of benzophenonetetracarboxylic dianhydride (hereinafter referred to as BTDA) and 76.0 g of TMEG were added as powders, and 3
After stirring for 0 minute, DMF in which TMEG was dissolved was added while paying attention to the viscosity to obtain a polyamic acid solution. Bond ply and CCL were prepared and physical properties were measured in the same manner as in Example 1. Table 1 shows the results.

[0055]

COMPARATIVE EXAMPLE 2 6 g of BAPP was added using 215.2 g of DMF and stirred for 15 minutes. Subsequently, 2 g of benzophenonetetracarboxylic dianhydride (hereinafter referred to as BPDA) was added. After stirring for 30 minutes, another 8.0 g of BPDA was added.
A slurry was prepared by using 8.0 g of DMF, and the solution was gradually added thereto while paying attention to the viscosity of the solution in the flask. Thereafter, the solution was allowed to stand with stirring for 1 hour to obtain a 23% SC polyamic acid solution.

The obtained polyamic acid solution was further added to DMF.
3588 g was added and diluted to adjust the viscosity to about 5 poise. Using this polyamic acid solution, a bond ply and a CCL were prepared in the same manner as in Example 1, and the characteristics were evaluated. Table 1 shows the results
Shown in

[0057]

Comparative Example 3 219.6 g of BAPP and 1282.8 g of DMF
Was sufficiently dissolved by stirring with a stirrer. After stirring for 15 minutes, 141.6 g of BPDA and 15.4 g of TMEG were charged as a powder. After stirring for 30 minutes, a solution in which 6 g of TMEG was dissolved in 100 g of DMF was gradually added while paying attention to the viscosity of the solution in the flask.
Then, the mixture was left for 1 hour with stirring. After that, 2166
g of DMF was added and stirred for 1 hour to obtain a polyamic acid solution. Using this polyamic acid solution, a bond ply and a CCL were produced in the same manner as in Example 1, and physical properties were measured in the same manner as in Example 1. Table 1 shows the results.

[0058]

Embodiments 3 and 4

[0059]

Comparative Examples 4 to 6 Using the CCLs prepared in Examples 1 and 2 and Comparative Examples 1 to 3, patterns of 10 mm and 1 mm width were formed by etching, and a 25 μm polyimide film with an acrylic adhesive was used as a cover layer. Thermocompression bonding. Crimping conditions were 160 ° C., 30 kgf / cm 2, and 1 hour. The laminate thus produced was subjected to a temperature of 40 ° C., 90 R
After absorbing moisture for 96 hours at H%, the mixture was passed through a reflow furnace (TRS-203N manufactured by Tamura Seisakusho) and the blister of the laminate was observed. As for the temperature conditions of the reflow furnace, when measured on the laminate, the preheat portion was 180 ° C. for 100 seconds, and the peak temperature was 265 ° C. Table 2 shows the results.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

As described above, the heat-resistant flexible thin metal sheet-clad laminate according to the present invention is excellent in solder heat resistance, particularly in heat resistance after moisture absorption treatment, and is excellent in FPC and rigid-
It is suitable for future new high-density packaging materials such as flex board materials, COF and LOC packages, and MCM, and other uses are not particularly limited.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4F100 AB01D AB10D AB17D AB33D AK01B AK47C AK49A AL05A AL05C BA03 BA04 BA06 BA07 BA10A BA10C CB00A CB00C EH46 EH462 EJ19 EJ192 EJ422 GB43 JJ03 EJ03 CA03E034J0304 JA12 JB01 KA23 LA01 LA08 LA09 MA02 MA10 MB03 NA20 4J043 PA02 PA05 PC015 PC065 QB26 QB31 RA35 SA06 SA43 SA44 SA71 SB01 SB02 TA14 TA22 TB01 TB03 UA121 UA131 UA132 UA141 VAUA UA151 UA672 UB011 UB121 UB1 VA051 VA062 VA071 VA081 XA15 XA16 XA19 YA06 YA08 ZB01 ZB50

Claims (8)

[Claims] 1. A polyimide resin obtained from a precursor of a polyimide resin, wherein the precursor has a general formula (Chemical Formula 1) (In the formula, k is an integer of 1 or more, m and n are each an integer of 0 or more where m + n is 1 or more. A and B are the same or different tetravalent organic groups, X and Y each represent a divalent organic group which may be the same or different.), And have a chemical structure of an amic acid represented by the following formula: The above is the following formula (Chemical formula 2) A thermoplastic polyimide resin having a tetravalent organic group shown in (1). 2. X and Y in the above general formula (Chem. 1) are represented by the following formulas (Chem. 3) to (Chem. 22). Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image Embedded image 2. The thermoplastic polyimide resin according to claim 1, wherein the thermoplastic polyimide resin is at least one selected from the group of divalent organic groups shown in (1). 3. A heat-resistant bond ply, wherein the adhesive layer containing the thermoplastic polyimide resin according to claim 1 is formed on one or both surfaces of a heat-resistant base film. 4. The heat-resistant bond ply according to claim 3, wherein the base film of the heat-resistant bond ply is a non-thermoplastic polyimide film. 5. A heat-resistant flexible metal foil-clad laminate obtained by thermally laminating the heat-resistant bond ply according to claim 3 and a thin metal sheet. 6. The heat-resistant flexible metal foil-clad laminate according to claim 5, wherein the thin metal sheet is selected from a copper foil and an aluminum foil. 7. The adhesive for a heat-resistant flexible metal foil-clad laminate according to claim 1 or 2. 8. When the solder bath dip test is performed at 260 ° C. for 60 seconds after the treatment at 40 ° C., 90 RH% for 192 hours, no turbidity of the thermoplastic polyimide layer and no peeling between the thermoplastic polyimide layer and the metal layer of the foil layer occur. The heat-resistant flexible metal foil-clad laminate according to claim 5 or 6, which is excellent in moisture-absorbing solder heat resistance.