JPS647863B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a laminate with excellent dimensional stability and interlayer adhesion. Conventionally, laminates made by impregnating a paper base material or a glass cloth base material with a resin and laminating and molding the same are well known, but it is difficult to achieve high density when mounting chip carriers on these laminates. For example, one high-density mounting method is to mount a leadless chip carrier on the board.
Since the chip carrier and the substrate have different coefficients of thermal expansion, there is a problem in that the connection between the chip carrier and the substrate deteriorates. Therefore, there has recently been a report that it is advantageous to mount a chip carrier made of a laminate made of aromatic polyamide fiber cloth with a negative coefficient of linear expansion (IEEE Transactions on
Components, Hybrids and Manufacturing
Technology Vol.CHMT.2, No.1, P.140.
March, 1979). This method has the advantage that it is possible to make the thermal expansion coefficients of the substrate and the chip carrier the same value, and that the reliability of the connection part is high. However, the biggest drawback of this substrate is that the resin and aromatic polyamide fibers are not compatible with each other, so when used as a laminate, the adhesive strength is weak and delamination is likely to occur. For this reason, it was difficult to withstand thermal cycle tests, making it difficult to put it into practical use. Therefore, in view of the above-mentioned drawbacks, the inventors of the present invention made extensive studies and used a composite cloth made by alternately weaving one or more aromatic polyamide fiber threads and glass threads for both warp and weft as a base material. They found that the interlayer adhesion of the laminate was improved and the dimensional stability in the plane direction was excellent. An object of the present invention is to provide a laminate with excellent dimensional stability and interlayer adhesion. The laminate of the present invention is made by laminating a predetermined number of prepregs obtained by impregnating the composite cloth with resin, and
In some cases, the composite cloth is formed by stacking copper foils and forming them under heat and pressure, and the weight ratio of the aromatic polyamide fiber threads and glass threads of the composite cloth is preferably 30 to 95% of the former.
The latter is 5-70%. If the aromatic polyamide fiber yarn is less than 30% (glass yarn is more than 70%), the dimensional stability will not be satisfactory, and if the aromatic polyamide fiber yarn is more than 95% (glass yarn). (less than 5%), the interlayer adhesion of the laminate will be poor. The aromatic polyamide fiber yarn is spun from an aromatic polyamide represented by the following general formula. (-Ar ₁ -CONH-)n (-Ar ₁ -CONH-Ar ₂ -NHCO-)n Here, Ar ₁ and Ar ₂ represent aromatic residues, and Ar ₁
Ar ₂ may be the same or different. As Ar ₁ and Ar ₂

【formula】

【formula】

【formula】

[Formula] (where X is a group selected from O, CH ₂ , S, SO ₂ , CO, etc.)
They may be used alone or in combination of two or more. moreover,
If it is less than 30 mol%

【formula】

【formula】

The solubility of the polymer can also be improved by incorporating the formula. Furthermore, these aromatic groups may be substituted with inert groups such as halogen, alkyl groups, and nitro groups. As the resin, organic materials such as thermosetting resins such as phenolic resin, epoxy resin, unsaturated polyester resin, polyimide resin, triazine resin, melamine resin, bis-diene polymer, polyethylene, polysulfone, polyamideimide,
There are linear polymers such as polyimide, silicone resins, and organic materials such as polyphosphazenes.
Mixtures and copolymers of the above resins can be used. EXAMPLES Hereinafter, the present invention will be specifically explained by showing examples. Example 1 Brominated bisphenol A type epoxy resin (epoxy equivalent: 480 g/eg) 90 parts by weight, cresol novolac type epoxy resin (epoxy equivalent: 220 g/eg)
eg) Methyl ethyl ketone and methyl cellosorg were added as solvents to 10 parts by weight, 4 parts by weight of dicyandiamide, and 0.2 parts by weight of benzyldimethylamine to make a varnish with a concentration of 37%. On the other hand, glass thread ECG75-1/
23.8S and Kevlar 49 (registered trademark of DuPont, i.e., poly(p-phenylene terephthalamide) fiber) are warped into separate warp beams, and two kinds of wefts are inserted, then both the warp and weft are made of glass using a J loom. A woven composite cloth in which two threads and Kevlar 49 are alternately arranged was prepared. Dip this composite cloth into the above varnish,
It was dried at 160°C for 5 minutes to obtain a prepreg. The resin content of this prepreg was 29.5% by weight (approximately 35% by volume). Next, 8 sheets of this prepreg and 2 sheets of copper foil (thickness
35μ) were placed on top of each other and pressed at 170°C for 60 minutes to obtain a copper-clad laminate with a thickness of 1.03mm. The coefficient of linear expansion in the plane direction of this copper-clad laminate is 5.8×
It was 10 ^-6 ℃ ^-1 . This measurement was carried out using a thermomechanical testing machine with a load of 2 g and a temperature increase rate of 5° C./mm. In addition, the copper foil peeling strength is 1.7Kg/cm,
The interlayer adhesion was 1 kg/cm or more. this is
Measurement was performed in accordance with the peel test method of JISC6481. Comparative Example 1 Glass cloth was impregnated with the same varnish as in Example 1 to make prepreg, and 80 kg/cm ² was heated from 8 sheets of prepreg and 2 sheets of copper foil at 170°C for 1 hour.
A copper-clad laminate was obtained by pressing at a pressure of . The interlayer adhesive strength of this laminate was 1 kg/cm or more, and the coefficient of linear expansion in the plane direction was 2.9×10 ⁻⁵ ° C. ⁻¹ . Comparative Example 2 40 parts by weight of phenol novolac type epoxy resin (epoxy equivalent: 180 g/eg), brominated phenol novolac type epoxy resin (epoxy equivalent: 285
g/eg) 60 parts by weight, dicyandiamide 6.4 parts by weight,
A varnish with a concentration of 37.5% by weight was prepared by adding methyl ethyl ketone and methyl cellolub to 0.1 part of benzyldimethylamine. This varnish was impregnated with a cloth made of polyp-phenylene terebutalamide fibers to obtain a coated cloth at a temperature of 162°C and a coating speed of 1.5 m/mm. 10 sheets of this prepreg and 2 sheets of 35μ thick copper foil
The sheets were stacked and pressed at 170° C. for 1 hour at a pressure of 80 kg/cm ² to obtain a copper-clad laminate with a thickness of 0.8 mm. The coefficient of linear expansion in the plane direction of this laminate is 5.5×10 ^-6
Although the temperature was ^-1 , the interlayer adhesive strength was 0.7 kg/cm. As can be seen from the above examples and comparative examples,
Comparative Example 1 has a large linear expansion coefficient, and Comparative Example 2 has weak interlayer adhesion, both of which have fatal flaws in terms of practical use. However, in the example, the linear expansion coefficient is 5.8 ×
It is found that the temperature is around 10 ^-6 °C ^-1 , which is equivalent to the coefficient of linear expansion of ceramics, and the interlayer adhesive strength is also large, making it usable for practical use. As explained above, the present invention has the effect of providing a laminate with excellent dimensional stability and interlayer adhesive strength.

Claims (1)

[Claims] 1. A prepreg obtained by impregnating a composite cloth with a resin, which is made by alternately woven one or more warp and weft yarns of 30 to 95% by weight of aromatic polyamide fiber yarn and 5 to 70% by weight of glass yarn. A laminate characterized by laminating a predetermined number of prepreg laminates, placing copper foil on the top and bottom of this prepreg laminate, heating and press-forming it.