JPS6345051A - Heat-resistant laminate - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a highly reliable heat-resistant laminate made of polyimide resins used as materials for electronic parts and the like.

[Conventional technology]

Polyimide resin is known as a material with excellent heat resistance and electrical properties. The laminate is used for a variety of purposes, including as a material for electronic components such as flexible printed circuit boards, and further development is expected in the future.

Thus, while it is hoped that polyimide resins will advance in lamination technology, as is well known, polyimide resins have weaknesses such as poor processability and poor adhesion, and are unable to form strong bonds when used alone. Therefore, at present, lamination is performed with the help of epoxy adhesives and the like which have poor heat resistance (for example, see Jikai No. 1-60-164387).

Therefore, in order to solve the essential problem of poor heat resistance of epoxy adhesives, a method using an adhesive layer consisting of aromatic polyamide-imide and an adhesive agent (Japanese Patent Application Laid-Open No. 55-1989-1) was developed.
Reference No. 15826 J) has also been proposed.

Unfortunately, however, none of these methods satisfies the recent high requirements for heat resistance.

[Problem that the invention seeks to solve]

In other words, the epoxy adhesives currently in use have an essential problem of being about 150°C inferior in heat resistance compared to polyimide resins, and this becomes a bottleneck that reduces the heat resistance of the entire laminate. There's a problem.

In addition, the adhesive made of aromatic polyamideimide and an adhesion promoter proposed to improve this problem does indeed have significantly higher heat resistance than epoxy adhesives, or does not exhibit high heat resistance when exposed to heat and humidity. The problem remained that adhesion was insufficient when subjected to both heat and humidity loads, and that reliability was lacking in harsh environments.

[Means for Solving the Problems] As a result of intensive studies to solve the above problems, the inventors of the present invention have found that by using an adhesive layer made of an aromatic polyamide-imide resin with a specific filler added, the inventors have improved the solder heat resistance. is excellent,
The present invention was achieved by discovering that an excellent laminate that does not change color even under high temperatures and has high adhesive reliability under hot and humid conditions can be obtained.

In other words, the present invention is characterized in that, in a laminate in which at least one layer is a polyimide resin layer, the contact layer is a composition having a polar organic solvent-soluble aromatic polyamide-imide resin and a highly thermally conductive filler. The present invention provides a heat-resistant laminate having the following properties.

The present invention will be explained in detail below.

At least one layer of the laminate of the present invention must be a polyimide resin layer.

Polyimide resin is usually Pyromellit 12m water and 4,
KAPTO is a resin produced from 4'-diamino-diphenyl ether through an intermediate of polyamic acid.
Commercially available products such as N (trade name manufactured by DuPont) can be used.

The other layers can be selected from metals, ceramics, plastics, and others depending on the purpose and use, but in the case of electronic component materials, especially flexible printed circuit boards, metal layers are often used.

Of course, the adhesive layer of the present invention can firmly adhere to both the metal layer and the polyimide resin layer.

The gold B layer can be applied to all metals such as copper foil and aluminum thin plate. Further, as the ceramic layer, all ceramics such as alumina, zirconia, silicon nitride, boron nitride, and silicon carbide can be used. Furthermore, other layers can also be used except for special ones.

Next, the aromatic polyamide-imide resin used in the adhesive layer, which is the main part of the present invention, is an aromatic polyamide-imide resin soluble in a polar organic solvent, and has the general formula carbonyl group or methylene group, and r) is 2 or more. (representing an integer) or a mixture thereof is used.

The reduced viscosity of the aromatic polyamide-imide resin used in the present invention is not particularly limited to 1 as long as it is 0.5 or more, but it is practical to have a reduced viscosity of around 3.5 based on the solution viscosity at the time of use. If the reduced viscosity is too low, the mechanical strength and flexibility will decrease, and if the reduced viscosity is too high, the solubility in polar solvents will decrease, making it impractical.

These aromatic polyamideimide resins can be prepared by known methods,
For example, 'IB' can be carried out by (1) reacting an aromatic diamine with anhydrous trimellitic dichloride or (2) reacting an aromatic diisocyanate with bisimidodicarboxylic acid.

This reaction (2) will be explained below as a representative example.

(X in the formula has the same meaning as above) or amine)
The aromatic diamine of (A) or (B) is reacted with trimellitic anhydride in a chronic organic solvent such as N,N-dimethylacetamide or N-methyl-2-pyrrolidone.

(A> aromatic diamines include 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenylsulfone,
Examples include 4,4'-diaminobenzophenone and 4,4'-diaminodiphenylmethane.

Further, among the aromatic diamine (A) and the aromatic diamine (B), the aromatic diamine (A>) is more preferable because it has excellent flexibility, heat resistance, and moisture resistance.

Examples of the polar organic solvent for the aromatic polyamide-imide resin of the present invention include N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, N-methyl-2-pyrrolidone, hexylymethylphosphoramide, and halogenated cresol. Alternatively, mixed solvents thereof, or mixed solvents of these and conventional solvents can be mentioned.

Next, the filler, which is another essential component constituting the adhesive layer of the present invention, must be a highly thermally conductive filler.

The high thermal conductivity filler mentioned here has a thermal conductivity of 0.05.
Cal/cm, sec, refers to an inorganic filler with high thermal conductivity of ℃ or higher. A specific example is beryllya (BeO
), magnesia (MqO), boron nitride (BN), alumina (AN 203), silicon carbide (S r C
), silicon nitride (SixN4), carbon (C) and mixtures thereof. Further, in consideration of toxicity, moisture resistance, and insulation, boron nitride or alumina is recommended as a particularly preferable filler.

The shape of the filler is not particularly limited, and any shape such as spherical, angular, acicular, layered, scale-like, etc. can be used. Further, the particle size can be used as long as it is a so-called fine powder, but it is usually 200 μm or less, particularly preferably 50 μm or less.

The blending ratio of the filler is 1 to 35% by volume, preferably 5% to 25% by volume. Filler blend ratio is high 1
If it is too low, the mechanical strength and flexibility will decrease, and if it is too low, the effect of improving heat resistance and moisture resistance will be small. Therefore, if the blending ratio of the filler is too low, defects will occur in the solder heat resistance test under more severe conditions.

Note that the optimum blending amount changes depending on the intended use, filler shape, and particle size, so the relationship between the physical properties of the filler to be used and the blending ratio has been preliminarily determined through experiments, and based on this. It is recommended that the formulation be determined based on the following criteria.

Conventionally known methods can be used to produce the filler-containing aromatic polyamide-imide resin composition that becomes the adhesive layer of the present invention. For example, it can be produced by adding aromatic polyamideimide resin to a polar solvent, completely dissolving it, adding a filler, and uniformly dispersing it using a stirring rack, a ball bowl, a three-roll mill, etc. Can be done.

Various other additives may be added to the adhesive layer composition of the present invention, if necessary. One example is the addition of a silane coupling agent, glass powder, glass weave, heat-resistant fiber, etc. to increase adhesiveness or mechanical strength.

Next, two typical manufacturing methods of the laminate of the present invention will be explained.

(2) A metal layer (thin plate, etc.) is coated with the adhesive layer composition of the present invention in paste form, and after preliminary drying, a polyimide resin layer (film, etc.) is overlaid and heat-pressed. Subsequently, this is heat-treated to form a laminate.

■ Necessary caulking A film of the adhesive layer composition of the present invention is produced and heat treated.

The solvent of the adhesive layer composition of the present invention is sprayed onto one side of each polyimide resin layer (film, etc.).

The adhesive layer composition film described above is sandwiched between the sprayed surfaces and bonded under heat and pressure. Subsequently, this is heat treated to form a laminate.

〔Example〕

Next, the present invention will be specifically explained using Examples and Comparative Examples, but the present invention is not limited thereto.

The evaluation methods and conditions for the laminates in Examples and Comparative Examples are as follows.

■Solder: Heat resistance: The test piece was immersed in a 300°C solder bath for 30 seconds.The presence or absence of blistering and peeling was observed when crushed.

(2) Color change: The color change was observed when the test piece was heat treated in an oven at 300°C for 30 minutes.

■Adhesion: Measured by the strip-tape method.

After cross-cutting the polyimide surface of the test piece according to the cross-cut test method of JIS K 5400,
ET tape was attached, then peeled off, and the number of remaining squares among the 100 squares was measured. In the compactness test, the laminate was heat-treated at 350'C for 3 hours and was left in a pressure cooker at 121°C and 2 atm for 1 hour, and its reliability under high temperature and heat and humidity was confirmed.

Example 1 4.4'-diaminodiphenyl ether (DADPE>
and organic polar solvent-soluble aromatic polyamideimide resin synthesized from trimellitic anhydride (TMAC).
Hereinafter abbreviated as FAI; reduced viscosity 1.6: specific gravity 1.5>
450 parts by weight of N-methylpyrrolidone was added to 100 parts by weight to dissolve the PAI. Then the average particle size is 1.5μ
A solution prepared by dispersing 1 part of 35 m of boron nitride fine powder (BN) (Showa Denko K.K., specific gravity: 2°25) in 60 parts by weight of NMP was mixed with the above FAI resin solution, and the BN was mixed with a ball mill. was uniformly dispersed to obtain a paste composition.

Next, the composition was coated in a paste form with a thickness of 50 μm on 5US304 whose surface had been polished, and after drying at 70°C for 2 minutes, a Kapton film (manufactured by Azuma DuPont, thickness 25 μTrL) was superimposed on the composition, and the top and bottom were coated. A cushioning material of Teflon and silicone rubber sheets was sandwiched between the two, and the material was heat-pressed at 5 K9/cti for 30 minutes at 180°C, and heat treated at 250°C for 20 minutes at normal pressure to produce a laminate of Kapton and SUS. did.

This laminate was evaluated using the method described above, and as a result, (1) No blistering or peeling was observed in terms of solder heat resistance, and (2) No change in color was observed. The result of the adhesion test was 100/100 for the blank. 100/100 for the high temperature treatment at 350°C for 3 hours.

All had good adhesion at 100/100 after the press treatment (7-couture treatment).

Comparative Example 1 Kapton for coverlay with adhesive (manufactured by Tsukan Co., Ltd., Nikaflex film thickness 25 μm, adhesive thickness 35 μm)
) and bonded to the same 5t JS304 as in Example 1 using the method and conditions specified by Nirakan Co., Ltd. to produce a laminate of Kapton and SUS.

This laminate was evaluated using the same method and conditions as in Example 1. As a result, blistering was observed in (1) solder heat resistance, and (2) the color was blackish brown, which significantly impaired the appearance. Note that the color change does not occur even when only the Kapton film is heat-treated at 300°C, but only when the film with the adhesive is heat-treated, so this discoloration is thought to be due to the poor heat resistance of the adhesive. It will be done. Furthermore, in the adhesion test, the blank was 100/100, but after high-temperature treatment at 350°C for 3 hours, after O/1001 pressure coating, it was 36/100, showing that the laminated layer of Example 1 had better heat and humidity resistance. It turned out that it was significantly inferior to the real thing.

Example 2 The composition used in Example 1 was applied to a thickness of about 10 mm using an applicator.
1J after making μm thin film, 130℃, 190℃
Each sample was heat-treated for 30 minutes. Next, N-methylpyrrolidone was sprayed thinly on one side of each of Kapton film (manufactured by DuPont Toshi, thickness 25μTrL) and a thin alumina plate (manufactured by Noritake, thickness 635μm), and the above film was placed in between. Kapton and alumina were layered and separated. Next,
Press from above and below with Teflon and silicone rubber sheet cushioning material, press at 6Kg/crti at 180℃ for 30 minutes, then release the pressure and press at 130℃, 190℃, 250℃
Heat treatment was performed for 10 minutes each to produce a laminate of Kapton and ceramic.

As a result of evaluating this laminate, no blistering or peeling was observed in (1) solder heat resistance, and no change in the thickness (2) was observed. ■
Adhesion is 100/100 in both Bran 9350℃ high temperature treatment and pressure cutter, reliable ↑1
It turned out to be a very high laminate.

Examples 3 to 7 Polyimide laminates as shown in Table 1 were produced by the same method as in Example 1, and each laminate was evaluated. The results are shown in Table 1.

Both laminates showed excellent effects.

(The following is a blank space) [Effects of the Invention] As explained above, the present invention compensates for the drawbacks of conventional polyimide resins, has excellent solder heat resistance, does not change color even under high temperatures, and has excellent adhesion under hot and humid conditions. The object of the present invention is to provide a laminate that exhibits the excellent effect of greatly improving reliability by a large amount.

Therefore, by using the heat-resistant laminate of the present invention, it is expected that the reliability of electronic components against heat will be further improved.

Furthermore, the adhesive composition of the present invention can be used in either liquid or film form, and also has the effect of greatly contributing to the simplification and economicalization of the manufacturing process of @peripherals.

Claims (1)

[Claims] 1. A laminate in which at least one layer is a polyimide resin layer, characterized in that the adhesive layer is a composition containing a polar organic solvent-soluble aromatic polyamide-imide resin and a highly thermally conductive filler. Heat-resistant laminate. 2 Polar organic solvent soluble aromatic polyamideimide resin has the general formula▲mathematical formula, chemical formula, table, etc.▼ (However, X represents an oxygen atom, sulfur atom, sulfonyl group, carbonyl group, or methylene group, and n is 2 or more. 2. The heat-resistant laminate according to claim 1, wherein the heat-resistant laminate is a resin represented by (representing an integer of ) or a mixture thereof. 3. The heat-resistant laminate according to claim 1, wherein the highly thermally conductive filler is boron nitride or alumina.