JPS59141283A - Metal foil insulating adhesive sheet - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal foil insulating adhesive sheet having an insulating adhesive layer provided on one side of a metal foil.

For electronic circuit applications such as hybrid ICs, an adhesive sheet consisting of a metal foil such as copper foil with an insulating adhesive layer formed on one side is used, and this is laminated and integrated onto a heat dissipation plate such as an aluminum plate via the adhesive layer. It is common practice to fabricate a circuit board using the same method (see FIG. 2). Conventionally, a semi-cured thermosetting resin such as an epoxy resin is used as the adhesive layer, and is completely cured when it is laminated and integrated with the heat sink.

However, as the performance of electronic components increases, the circuit boards produced by the conventional method have insufficient voltage resistance characteristics, and improvements in these characteristics have been strongly desired. Also, HYPUT IC
For example, high heat dissipation through a heat sink is required, but the above-mentioned conventional devices cannot necessarily satisfy this requirement.

As a result of intensive studies in light of the above circumstances, the inventors have discovered that both the voltage resistance and heat dissipation properties of this type of adhesive sheet can be improved by making improvements to the insulating adhesive layer formed on one side of the metal foil. This led me to make this invention.

That is, the present invention provides a base layer formed by heating and curing a thermosetting resin composition containing a thermosetting resin and 20 to 300 parts by weight of an inorganic filler per 100 parts by weight of the resin on one side of a metal foil. The present invention relates to a metal foil insulating adhesive sheet, characterized in that an adhesive layer is formed on this layer, and is made of a semi-cured thermosetting resin composition layer.

Note that the thermosetting resin composition layer constituting the adhesive layer is preferably the same thermosetting resin composition as that used for the base layer. Here, similar means a thermosetting resin that is cured with the same type of curing agent. Particularly preferably, the same thermosetting resin composition is used for both.

FIG. 1 shows an example of a metal foil insulating adhesive sheet of the present invention, in which 1 is a copper foil or other metal foil, 2 is the metal foil 1
A base layer 3 is formed on one side of the base layer 2, and 3 is an adhesive layer provided on the base layer 2. When using this adhesive sheet, for example, as shown in FIG. 2, it may be laminated and integrated onto a heat dissipating plate 4 such as an aluminum plate with the adhesive layer 3 side facing inside.

The base layer 2 is formed by applying a thermosetting resin composition containing a thermosetting resin and 20 to 300 parts by weight of an inorganic filler per 1.00 parts by weight of the resin onto the metal foil 1 and curing it by heating. The adhesive layer 3 is formed by applying a thermosetting resin composition in a semi-cured state onto the base layer 2, and is completely heat-cured when laminated and integrated with the heat dissipation plate 4. Ru.

Examples of the thermosetting resin used to form the base layer 2 and the adhesive layer 3 include epoxy resin, polyimide resin, thermosetting polyester resin, and silicone resin. Among these, epoxy resin is used from the viewpoint of heat resistance and adhesiveness. and polyimide resin are particularly preferred.

As the above-mentioned epoxy resin, any compound having at least two or more epoxy groups in the molecule can be used, such as bisphenol-based epoxy resin, novolac-based epoxy resin, polyphenol-based epoxy resin,
Polyhydroxybenzene-based epoxy resin, polyglycol-based epoxy resin, aromatic carboxylic acid-based epoxy resin,
Examples include alicyclic epoxy resins and nitrogen-containing epoxy resins. Among these, bisphenol-based epoxy resins and novolak-based epoxy resins are preferred.

In addition, the above-mentioned polyimide resins include addition polymerization types containing maleimide as a main component, those in which imide groups are introduced into unsaturated polyesters, those in which bismaleimide and triazine resin are reacted, or those modified with epoxy resins. An imidized product of a reaction product of butanetetracarboxylic acid and an aromatic diamine is used.

As the inorganic filler used to form the base layer 2, glass powder, mica powder, silica powder, alumina powder, etc. with an average particle size of about 3 to 50 μm are preferably used as they do not impair heat resistance and electrical insulation properties. It will be done. This inorganic filler is mainly used to improve heat dissipation when the adhesive sheet is bonded and integrated with the heat dissipation plate, and is used to improve heat dissipation when the adhesive sheet is integrated with the heat dissipation plate.
20 to 300 parts by weight, preferably 100 parts by weight
The above object can be achieved by using up to 200 parts by weight. It should be noted that if it exceeds 300 parts by weight, heat resistance and uniform coating properties will be poor, making it unsuitable.

In this invention, it is preferable that the thermosetting resin composition constituting the adhesive layer 3 also contains an inorganic filler. In this case, the type, particle size, and addition ratio of the inorganic filler to the thermosetting resin are the same as those described above.

The thermosetting resin or each thermosetting resin composition containing the same and an inorganic filler for forming the base layer 2 and the adhesive layer 3 may be completely the same between both layers 2 and 3. However, the types and amounts of resins and fillers may be slightly different. Further, each composition can contain a curing agent and various conventionally known additives as appropriate, but the types and amounts of these should also be different between both layers 2.3 to give each layer their own characteristics. There is no problem.

Among the base layer 2 and the adhesive layer 3, a fiber base material can be embedded in the base layer 2 in particular for the purpose of further improving the withstand voltage. Examples of this base material include woven and nonwoven fabrics made of cotton, rayon, polyester, glass, aromatic polyamide, and ceramic, among which woven and nonwoven fabrics made of glass and aromatic polyamide, which have excellent heat resistance, are suitable. .

Moreover, it is preferable that the porosity is 25 to 70%.

The thickness of the base material is generally about 0.02 to 0.10 m. In addition, it is also possible to provide such a fiber base material in the adhesive layer 3 depending on the case.

In the metal foil insulating adhesive sheet consisting of the metal foil 1, base layer 2, and adhesive layer 3, the thickness of the metal foil 1 is 10
The thickness of the base layer 2 is usually 10 to 100 microns, preferably 30 to 60 microns, and the thickness of the adhesive layer 3 is 5 to 50 microns, preferably 10 to 30 microns. The thickness of the entire adhesive sheet is usually 50 to 20
It is about 0μ. In particular, by setting the base layer 2 and the adhesive layer 3 to the above-mentioned thickness relationship, good results can be obtained in voltage resistance characteristics and heat dissipation properties, and also good results can be obtained in adhesive properties when bonding to the heat dissipation plate 4.

As is clear from the above structure, the metal foil insulating adhesive sheet of the present invention has an insulating adhesive layer provided on one side of the metal foil, a fully cured layer (base layer) made of a thermosetting resin composition, and a semi-cured layer. layer (adhesive layer), the semi-cured layer can maintain adhesion to the heat sink, and the presence of the completely cured layer allows it to be made up of a conventional semi-cured layer alone. The withstand voltage characteristics are significantly improved compared to the standard. The reason for this is not necessarily clear at present. It is speculated that with the conventional method, when bonding and integrating with the heat sink, air is trapped and uncured parts are left behind, which has a negative effect on the withstand voltage characteristics. It is believed that the formation of a hardened layer reduces the above-mentioned problems.

In addition, in the metal foil insulating adhesive sheet of the present invention, the completely cured layer or the layer in a semi-cured state contains an inorganic filler, so that the heat dissipation plate can be completely cured while the semi-cured layer is completely cured. When the metal foil is bonded and integrated with the metal foil, the thermal conductivity from the metal foil to the heat sink is significantly improved, and thereby the heat dissipation performance of the circuit board is highly improved.

EXAMPLES Below, examples of the present invention will be described in more detail. In addition, in the following, parts shall mean parts by weight.

Example 1 35 μ thick copper foil (trade name: CFT manufactured by Shushu Metal Foil & Powder Industry Co., Ltd.)
-3) Novolac epoxy resin (trade name Epon #154 manufactured by Yuka Shell Co., Ltd.) and bisphenol epoxy resin <trade name Epo manufactured by Yuka Shell Co., Ltd.
Mixed resin 100 with a weight ratio of 8:2 (n # 828)
4 parts of finely ground dicyandiamide and 20 parts of alumina powder
An epoxy resin composition obtained by uniformly mixing 0 parts of It was embedded and then heat treated at 180° C. for 30 minutes to completely harden it.

The cured layer thus formed with a thickness of 50 μm was used as a base layer, and the same epoxy resin composition as above was further coated on this layer to a thickness of 20 μm, followed by heat treatment at 130° C. for 20 minutes. A semi-cured adhesive layer was formed.

The obtained metal foil insulating adhesive sheet was placed on a 1.6N thick aluminum plate at 180°C with the adhesive layer inside at 50 kg.
/ am 2. After lamination and integration under the conditions of 60 minutes, the results of examining the dielectric breakdown voltage, solder heat resistance, thermal conductivity, and peel strength (between the aluminum plate and the substrate) are shown in the table below. That's right.

Comparative Example 1 The thickness of the uncured adhesive layer was 70μ (corresponding to the total thickness of the base layer and adhesive layer in Example 1) without providing a cured layer that would become a completely cured base layer, and this A metal foil insulating adhesive sheet was prepared in the same manner as in Example 1, except that alumina powder was not included in the adhesive layer, and this was laminated and integrated with an aluminum plate under the same conditions as in Example 1 to evaluate its performance. I looked into it.

The results were as shown in the table below.

Example 2 100 parts of a polyimide modified resin (trade name Nylatol 600W, manufactured by Tokyo Electric Industries, Ltd.) and mica powder (Topy Industries, Ltd.) were applied to the adhesive-treated surface of a 35 μ thick copper foil (trade name MW, manufactured by Mitsui Kinzoku Kogyo Co., Ltd.). Product name: PDM-K (G) #3
A polyimide resin composition prepared by uniformly mixing 100 parts of 25"l was coated to a thickness of 30μ, and then 15"l was coated to a thickness of 30μ.
Heat treatment was performed at 0°C for 15 minutes and at 200°C for 20 minutes to completely cure (imidize).

The cured layer with a thickness of 30 μm thus formed is used as a base layer, and on this layer, a maleimide resin (Rhone
(Product name: KERIMID601 manufactured by Poluenc)
1. A polyimide resin composition prepared by uniformly mixing 0 parts of O with 100 parts of mica powder is dissolved in dioxane to a concentration of 50% by weight, and the thickness after drying is 1.
After coating to give a thickness of 0 μ, the adhesive layer was dried by heating at 120° C. for 20 minutes to form a semi-cured adhesive layer.

The obtained metal foil insulating adhesive sheet was placed on an aluminum plate of 1.6 fin thickness with the adhesive layer inside at 180°C for 1,000°C.
After laminating and integrating under the conditions of K97 cm and 2.60 minutes, the same performance test as in Example 1 was conducted.

The results were as shown in the table below.

Comparative Example 2 The thickness of the uncured adhesive layer was set to 40μ (total thickness of the base layer and adhesive layer of Example 2) without providing a cured layer that would become a completely cured base layer, and this adhesive layer A metal foil insulating adhesive sheet was produced in the same manner as in Example 2, except that mica powder was not included therein, and this was laminated and integrated with an aluminum plate under the same conditions as in Example 2, and its performance was investigated. Ta.

The results were as shown in the table below.

As is clear from the above results, the metal foil insulating adhesive sheet of the present invention can greatly improve the withstand voltage, provide good heat dissipation, and have satisfactory adhesion and heat resistance. I understand that there is something.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the metal foil insulating adhesive sheet of the present invention, and FIG. 2 is a sectional view showing a state in which the above-mentioned substrate is laminated and integrated with a heat sink. 1 metal foil, 2 base layer, 3...adhesive layer. Patent applicant: Shinko Kagaku Kogyo Co., Ltd. (1 other person) No. 1
Figure 2

Claims (1)

[Claims] (1) On one side of the metal foil, a base layer is formed by heating and curing a thermosetting resin composition containing a thermosetting resin and an inorganic filler of 20 to 300 parts by weight per 100 parts by weight of the resin. A metal foil insulating adhesive sheet, further comprising an adhesive layer made of a semi-cured thermosetting resin composition formed on this layer.