JPH01114433A - Heat resistant laminated body - Google Patents

Abstract

PURPOSE:To increase the heat resistance to a solder and improve remarkably the reliability in adhesiveness under high temp. humid atmosphere by using a composition having aromatic polyamide-imide resin soluble in a polar organic solvent and a filler with high heat-conductivity as an adhesive layer in a laminate wherein, at least its one layer is a metal while the other layer is a metal or a ceramics. CONSTITUTION:An aromatic polyamide-imide resin is added to a polar organic solvent and after complete solution, a filler is added followed by uniform diffusion by using a stirrer, a ball-mill or a three-roller type roll-mill thereby obtaining a composition to be used as an adhesive layer. Then the obtained composition is coated on the layer made of a metal or ceramics, and after preliminary drying, a metallic layer is superposed thereon followed by heating and pressing. After that it is subjected to heat treatment and formed into a laminate. Thus, a laminate excellent in heat resistance to a solder, remarkably improved in the reliability in adhesiveness under high temp. humidity atmosphere can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a highly reliable heat-resistant laminate in which metals and metals and/or ceramics are laminated to be used as materials for electronic components and the like.

[Conventional technology]

Metals and ceramics are materials with excellent thermal conductivity, and their laminates are used in a variety of applications, including materials for electronic components such as aluminum substrates, and further development is expected in the future.

Conventionally, epoxy adhesives have been mainly used for the adhesive layer of this laminate (for example, Japanese Patent Laid-Open No. 58-152
(See No. 90).

However, epoxy adhesives have a problem in that they do not have sufficient heat resistance.

Therefore, a method has been proposed that uses an adhesive layer made of aromatic polyamideimide, which has better heat resistance than epoxy adhesives, and an adhesive agent (Japanese Patent Laid-Open No. 55-1582
(See No. 6).

Unfortunately, however, none of these methods has been able to satisfy the recent demands for high heat resistance.

(Problems to be solved by the invention) In other words, there are approximately 2 types of epoxy adhesives in practical use.
It has a heat resistance of only about 00°C and lacks reliability at high temperatures.

On the other hand, although adhesives made of aromatic polyamide-imide and adhesion promoters do show significantly higher heat resistance than epoxy adhesives, they are difficult to resist when exposed to both heat and humidity. In such cases, the adhesion is not sufficient,
The problem remained that it lacked reliability in harsh environments.

[Means for Solving the Problems] As a result of extensive studies to solve the above problems, the inventors of the present invention have found that heat resistance can be improved by using an adhesive layer made of aromatic polyamideimide resin with a specific filler added. The present invention was achieved by discovering that an excellent laminate that has excellent adhesion reliability under hot and humid conditions and that takes advantage of the high heat resistance of metals or ceramics has been obtained.

That is, in the present invention, at least one layer is metal,
To provide a heat-resistant laminate in which the other layers are metal or Hiramix, and the adhesive layer is a composition comprising a polar organic solvent-soluble aromatic polyamide-imide resin and a highly thermally conductive filler. It is.

The present invention will be explained in detail below.

At least one layer of the laminate of the present invention is a metal layer, and other layers can be selected from metal or reramic depending on the purpose. Electronic component materials, especially heat-dissipating substrates, are often metals.

As the metal layer, all metals that can be formed into a layer, such as copper and aluminum, can be used. Further, the ceramic layer may be made of ceramic, and various materials can be used. For example, alumina, zirconia, titanium nitride, boron nitride, silicon carbide, etc. can be used.

Next, the aromatic polyamide-imide resin used for 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 (where X is an oxygen atom, a sulfur atom, a sulfonyl group, A resin represented by a carbonyl group or a methylene group, where n is an integer of 2 or more, or a mixture thereof is used.

The reduced viscosity of the aromatic polyamide-imide resin used in the present invention is not particularly limited 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 organic solvents will decrease, making it impractical.

These aromatic polyamideimide resins can be prepared by known methods,
For example, it can be produced by (1) reacting an aromatic diamine with trimellitic anhydride, or (2) reacting an aromatic diincyanate with bisimidodicarboxylic acid.

Among these, reaction (2) will be explained below as a representative example.

(X in the formula has the same meaning as above) or amine)
(A) (8) Any of the aromatic diamines and trimellitic anhydride are reacted in a polar organic solvent such as N,N-dimethylacetamide or N-methyl-2-pyrrolidone.

<A) Aromatic diamines include 4.4'-diaminodiphenyl ether, 4.4'-diaminodiphenylsulfide, 4.4'-diaminodiphenylsulfone,
Examples include 4.4'-diaminobenzophenone and 4.4'-diaminodiphenylmethane.

Furthermore, 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, hexamethylphosphoramide, halogenated cresol or Examples include mixed solvents of these or mixed solvents of these and other commonly used solvents.

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 a highly thermally conductive inorganic filler of ``c or higher.A specific example is Beryllya (Beryllium).
d), magnesia (MqO), boron nitride (BN),
Alumina (A, 1!203), silicon carbide (SiC),
Mention may be made of silicon nitride (Si3N4), carbon (C) and mixtures thereof. Furthermore, in consideration of toxicity, moisture resistance, and insulation, boron nitride or alumina is recommended as a particularly preferred 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. If the blending ratio of the filler is too high, mechanical strength and adhesiveness 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 ratio will vary 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 should be preliminarily determined through experiments.
It is recommended that formulations be determined based on this.

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 an aromatic polyamide-imide resin to a polar organic solvent, dissolving it completely, adding a filler, and uniformly dispersing it using a stirrer, a ball mill, a three-roll mill, etc.

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 fiber, heat-resistant fiber, etc. to increase adhesiveness or mechanical strength.

Next, two typical '14m methods for producing the laminate of the present invention will be described.

(2) A layer (such as a thin plate) of metal or ceramics is coated with the adhesive layer composition of the present invention in the form of a paste, and after preliminary drying, a layer of metal (such as a thin plate) is overlaid and bonded under heat and pressure. Next, heat treatment is performed to form a laminate.

(2) A film of the adhesive layer composition of the present invention is prepared and heat-treated in advance.

The solvent of the adhesive layer composition of the present invention is sprayed onto both sides of the film of this adhesive layer composition. This is sandwiched between the metals to be bonded or between the metals and the ceramics and bonded under heat and pressure.

〔Example〕

Next, the present invention will be specifically explained using Examples and Comparative Examples.
The present invention is not limited to these.

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

■Solder, test piece immersed in 300℃ solder bath for 30 seconds M
Gender: The presence or absence of blistering and peeling when crushed was checked.

■Density: Measured using the cross-cut tape method.

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

■Adhesion: Measured according to JIS C6481 peel strength test method.

Example 1 4.4'-diaminodiphenyl ether (DADPE)
and organic polar solvent-soluble aromatic polyamideimide resin synthesized from trimellitic anhydride (TMAC).
Hereinafter abbreviated as PAI: reduced viscosity 1.6: specific gravity 1.5)
450 parts 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 20 parts by weight of boron nitride fine powder (BN> (Showa Denko Co., Ltd. Showbi-N: specific gravity 2.25) in 50 parts by weight of NMP and the above PAI resin solution was mixed with the above PAI resin solution, and BN was mixed with a ball mill. were uniformly dispersed to obtain compositions of Base 1 to 1.

Next, apply the composition in paste form to a copper plate (thickness 1 m).
After pre-drying at 90°C for 10 minutes, this composition was layered with rolled copper foil (thickness 35μTrL), cushioning materials of Teflon and silicone rubber sheets were sandwiched between the upper and lower sides, and the composition was heated to 10mm using a press. /ci
Heat and pressure bonding was carried out at 180°C for 30 minutes.

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. Also, in the adhesion test, the blank was 1.61Nff/CI.
i, 1.4ONg/ar after high temperature treatment at 350℃ for 3 hours
After t1 pressure-packing treatment (121° C., 2 atm pressure, 1 hour), the adhesion was 1.55 KI/cm, which was good in all cases.

Example 2 The composition used in Example 1 was applied to a thickness of about 10 mm using an applicator.
After producing μm-thin films, they were heat-treated at 130° C. and 190° C. for 30 minutes, respectively. Next, N-
Spray a thin layer of methylpyrrolidone onto aluminum (15μ thick) and thin alumina plates (Noritake, 635μ thick).
m) and press from above and below with cushioning material of Teflon and silicone rubber sheet, 5 to 3/cM, 180℃.
, A laminate of aluminum foil and alumina was obtained by heating and pressing in a press for 30 minutes.

As a result of evaluating this laminate using the same method and conditions as in Example 1, ■■ Blistering was observed in the solder heat resistance, ■■Adhesion test was 100/100 in the blank, 100/100 in the high temperature treatment at 350°C, and pressure shoes. After Kerr treatment, the ratio was 100/100, indicating that the laminate was extremely reliable.

Examples 3 and 4 Metal 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.

Comparative Example 1 Polyimide varnish (Hilenie 220% solution manufactured by Toshisha Co., Ltd.)
A solution prepared by dispersing 500 parts by weight of BN and 20 parts by weight of BN (Showa Denko K.K., Shobi-N) in 50 parts by weight of NMP was mixed, and the BN was uniformly dispersed using a ball meal. Next, a copper plate and an aluminum foil were bonded under heat and pressure in the same manner and under the same conditions as in Example 1 to produce a laminate, and evaluated in the same manner.

The results are shown in Table 2.

Comparative Example 2 Bisphenol-type epoxy AER331 manufactured by Asahi Kasei Co., Ltd. Epoxy equivalent weight 180-200) 100 parts by weight and BN2
A solution containing 0 parts by weight of NMP in 50 parts was mixed, and 8N was uniformly dispersed using a ball mill.

Next, add N
A solution dissolved in 75 parts by weight of M P was added to the above BN mixed epoxy and stirred. Next, a copper plate and an aluminum foil were bonded under heat and pressure in the same manner and under the same conditions as in Example 1 to produce a laminate, and evaluated in the same manner.

The results are shown in Table 2.

Comparative Example 3 NMP400 was added to 100 parts by weight of PAI used in Example 1.
The heavy lifting section was disassembled into a weighted section. Next, a solution in which 150 parts of BN was dispersed in 1 part of 200 parts of NMP was mixed, and the BN was uniformly dispersed using a ball mill.

Next, a copper plate and an aluminum foil were bonded under heat and pressure in the same manner and under the same conditions as in Example 1 to produce a laminate, and evaluated in the same manner.

The results are shown in Table 2.

(The following is a blank space) [Effects of the Invention] As explained above, the present invention provides a laminate that has excellent solder heat resistance and also exhibits the excellent effect of improving adhesion reliability under hot and humid conditions to a large degree. This is what we provide.

Therefore, by using the heat-resistant laminate of the present invention,
It is expected that the reliability of electronic components against heat will further improve. Further, the heat-resistant V1 layered body of the present invention has the advantage that the manufacturing process thereof is simple and efficient.

Applicant: Nippon Kokoshi Kogyo Co., Ltd. Agent Patent Attorney Kazuya Nozaki

Claims (1)

[Claims] 1. A laminate in which at least one layer is made of metal and the other layers are made of metal or ceramic, and the adhesive layer contains a polar organic solvent-soluble aromatic polyamide-imide resin and a highly thermally conductive filler. A heat-resistant laminate characterized by being a material. 2 Polar organic solvent soluble aromatic polyamideimide resin has the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (However, X is an oxygen atom, a sulfur atom, a sulfonyl group, 2. The heat-resistant laminate according to claim 1, wherein the heat-resistant laminate is a resin represented by a carbonyl group or a methylene group, and n represents an integer of 2 or more, or a mixture thereof. 3. The heat-resistant laminate according to claim 1, wherein the highly thermally conductive filler is boron nitride or alumina.