JP2000141541A - Metallic laminate showing high peel strength - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the peel strength between a metal and an insulating layer by enhancing the rupture strength of an adhesive layer. SOLUTION: The metallic laminate, in principle, uses a thermoplastic resin for an adhesive layer between a metal and an insulating layer to be laminated together and whatever material may be suitable, provided that the rupture strength is set as 100 MPa or more and 170 MPa or less. Further the heavier the molecular weight of the adhesive layer becomes, the higher rupture strength. Consequently the rupture strength of the adhesive layer can be controlled by the molecular weight of the adhesive layer. The molecular weight of the adhesive layer can be made higher by approximating the molar ratio A/B of monomers A, B to 1 when two different kinds of the monomer as a raw material are used. The metals to be laminated are Cu, Fe and the like. For the formation of the insulating layer, an amide varnish or the like is applied as the adhesive layer, on a metallic foil and a process such as curing or using an adhesive sheet is employed. Besides, the insulating layer and the metal are bonded together by heat pressing, lamination or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal laminated board widely used for flexible wiring boards and the like, wherein a thermoplastic resin such as polyimide, polyamide or polyamideimide is used for an adhesive layer between a laminated metal and an insulating layer. It is.

[0002]

2. Description of the Related Art Conventionally, it has been considered desirable that the metal peel strength of a metal laminate is 1.0 kg / cm or more. In particular, with the recent trend toward miniaturization and portability of electronic components, processing of fine patterns and demand for connection reliability thereof are increasing. For the high reliability of the circuit pattern, the adhesive force between the metal and the insulating layer which forms the circuit is required. However, in a normal laminated plate, there is a problem that the peel strength varies because the breaking strength is not controlled only by improving the wettability and adhesion of the adhesive layer to the metal.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to improve the peel strength between an insulating layer and a metal in a metal laminate,
It is to achieve high reliability of a wiring pattern at the time of processing.

[0004]

As a result of investigations, the present inventors have found that the peel strength between the metal and the insulating layer depends not only on the wettability and adhesion of the adhesive layer to the adherend, but also on the breaking strength of the adhesive layer itself. Also found to be dependent. The present invention not only enhances the wettability and adhesion of the adhesive layer with the metal and the insulating layer, but also increases the breaking strength of the adhesive layer, increases the peel strength between the metal and the insulating layer, and provides a highly reliable metal laminate for connection. It is characterized by providing a board. According to the present invention, a metal laminate having a high peel strength between a metal and an insulating layer can be obtained, so that a substrate having excellent workability at the time of forming a pattern such as a printed circuit board or a TAB substrate and having high connection reliability can be obtained. It becomes possible.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The metal laminate according to the present invention is based on the use of a thermoplastic resin for the adhesive layer between the metal to be laminated and the insulating layer, and the material is not limited as long as the breaking strength is regulated to 100 MPa or more and 170 MPa or less, but polyimide, Polyamide, polyamide imide and the like are used.

[0006] The breaking strength of the adhesive layer can be controlled by controlling the molecular weight of the adhesive layer. That is, the breaking strength increases as the molecular weight of the adhesive layer increases. The molecular weight of the adhesive layer can be increased by making the molar ratio A / B of the monomers A and B closer to 1 when two kinds of monomers are used as raw materials. The molecular weight can also be increased by adding a curing agent into the adhesive layer.
The material to be laminated is not limited, and the same applies to the case of forming a multilayer laminate. As the metal to be laminated here, specifically, stainless steel, Cu, Fe, Ni, Mo, A
l and the like.

To form an insulating layer, a metal foil is coated with polyimide, polyamide imide, or amide varnish to serve as an adhesive layer.
There are a method of curing and a method of using an adhesive sheet. Non-thermoplastic resin is usually used for the base film of the adhesive sheet, specifically, polyimide, polyamide,
Polyamide imide, nylon and the like are used. More specifically, a non-thermoplastic Ube Industries polyimide film U
and a polyimide film Kapton series manufactured by DuPont and an amide film Aramica series manufactured by Toray. The bonding between the insulating layer and the metal is performed by hot pressing, laminating, or the like.

[0008]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Example 1 A polyimide film, Apical HP (12.5 μm thick) manufactured by Kaneka Chemical Industry Co., Ltd. was used as a base film, and thermoplastic polyimide PI-Pm (thickness 3) was formed on both sides of the base film.
μm), and an all-polyimide adhesive sheet,
Nippon Steel stainless steel foil SUS304H-TA (18 μm thick) was laminated on one side of the adhesive sheet, and heated and pressed to measure the adhesive strength. A strip of the adhesive sheet having a width of 5 mm and a length of 100 mm was thermocompression-bonded to stainless steel foil at 350 ° C., 50 kg / cm ² for 10 seconds.

A sample is prepared and a pulling speed of 50 mm / min
The value of the peel strength under the following conditions is shown. The peel strength was measured by changing the breaking strength of PI-Pm used for the adhesive sheet. Table 1 shows the measurement results. PI-Pm with a breaking strength of 103 MPa has an adhesive strength of 1.1 kg / cm. PI-Pm with a breaking strength of 115 MPa is adhesive strength
1.3kg / cm. PI-Pm with a breaking strength of 138MPa has an adhesive strength of 1.5kg / c
m.

[0010]

[Table 1]

[Comparative Example 1] A polyimide film, Apical HP (12.5 μm thick) manufactured by Kanegafuchi Chemical Industry Co., Ltd. was used as a base film, and thermoplastic polyimide
Pm (thickness: 3 μm), all-polyimide adhesive sheet, and Nippon Steel stainless steel foil SUS304H-TA (thickness: 18
μm) was laminated on one side of the adhesive sheet, and heated and pressed to measure the adhesive strength. A strip of the adhesive sheet having a width of 5 mm and a length of 100 mm was thermocompression-bonded to stainless steel foil at 350 ° C., 50 kg / cm ² for 10 seconds. Make a sample, pulling speed 50mm
It was shown by the value of the peel strength under the condition of / min. The peel strength was measured by changing the breaking strength of PI-Pm used for the adhesive sheet. Table 2 shows the measurement results. PI-Pm with a breaking strength of 72 MPa
Has an adhesive strength of 0.6 kg / cm. PI-Pm with a breaking strength of 67 MPa has an adhesive strength of 0.6 kg / cm. PI-Pm with a breaking strength of 81 MPa has an adhesive strength of 0.9 kg /
cm.

[0012]

[Table 2]

[Example 2] US Olin copper foil C7025 foil
(Thickness 18μm) Polyamide acid varnish is applied on the top layer. Among them, PI-A made by Mitsui Chemicals is formed on the uppermost layer, cured, and copper-clad laminate with adhesive layer (to be referred to as WF hereinafter) with a total thickness of 30μm. It was created. This WF formed into a strip having a width of 5 mm and a length of 100 mm was used as stainless steel SUS304 (thickness: 20 mm) manufactured by Nippon Steel.
μm) under a condition of 300 ° C., 75 kg / cm ² and 60 seconds.
The strip-shaped WF of this sample was drawn at SU at a pulling speed of 50 mm / min.
It was peeled off from S304 and the peel strength was measured. The peel strength was measured by changing the breaking strength of PI-A manufactured by Mitsui Chemicals, which is an adhesive layer of WF. Table 3 shows the results. PI-A breaking strength 115M
At Pa, the peel strength is 1.2 kg / cm. When the PI-A breaking strength is 120 MPa, the peel strength is 1.3 kg / cm. Peel strength 1.5 kg / cm when PI-A breaking strength is 154 MPa.

[0014]

[Table 3]

[Comparative Example 2] Copper foil C7025 made by Ohlin, USA
(Thickness 18μm) Polyamide acid varnish is applied on it, Mitsui Chemicals PI-A is formed on the uppermost layer, and cured,
Copper-clad laminate with adhesive layer with total thickness of 30μm (hereinafter referred to as WF)
It was created. This WF was made into a strip with a width of 5 mm and a length of 100 mm.
m) was thermocompression bonded at 300 ° C., 75 kg / cm ² for 60 seconds. SUS3 at a pulling speed of 50 mm / min.
04 was peeled off, and the peel strength was measured. The peel strength was measured by changing the breaking strength of PI-A manufactured by Mitsui Chemicals, which is an adhesive layer of WF. Table 4 shows the results. PI-A breaking strength 53MP
In the case of a, the peel strength is 0.5 kg / cm, when the breaking strength of PI-A is 71 MPa, the peel strength is 0.6 kg / cm, and when the breaking strength of PI-A is 82 MPa, the peel strength is 0.8 kg / cm.

[0016]

[Table 4]

[0017]

As shown in the examples, the present invention improves the peel strength of the metal laminate by increasing the breaking strength of the adhesive layer, and provides a highly reliable wiring board.

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Claims (1)

[Claims] 1. A metal foil having a breaking strength of 100 MPa or more,
A metal laminate exhibiting high peel strength, comprising an adhesive layer having a pressure of 170 MPa or less.