JPH0349932A - Adhering method of copper to resin - Google Patents

Abstract

PURPOSE:To heighten the adhesion strength of copper to resin and its acid resistance by a method in which when copper is stuck to resin, the process forming a copper oxide-layer on the surface of copper and the process reducing the formed copper oxide-layer to metallic copper by the acid reducing solution with at most a specified value of E16 A, are used. CONSTITUTION:When copper is stuck to resin, after the copper oxide layer formed on the surface of the copper has been reduced to metallic copper by the acid reducing solution with at most 7.0 of E 16 A, if they are pressure bonded under heating, excellent acid resistance and adhesion strength may be obtained. Since acid reducing solution is used, the water cleaning effect after dipping is excellent, and its fatty layer is not deteriorated. As the copper oxide layer-forming method, the water solution containing oxidizing agent is preferably used. In order to reduce the formed copper oxide layer to metal, the acid solution in which at least one kind in amine boran group shown by the general formula of BH3.NHRR'(R,R':H, CH3, CH2, CH3) is mixed with the chemical of boron group, is preferably used.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of adhering copper and resin that achieves both adhesive strength and acid resistance, and particularly relates to a method of adhering copper and resin, which is created by laminating and adhering a copper circuit layer and a resin layer. The present invention relates to a method for adhering copper and resin suitable for manufacturing multilayer printed wiring boards.

[Conventional technology]

Conventionally, when adhering copper and resin, a method has been known in which a copper oxide layer is formed on the copper surface in order to improve the adhesion force. This method was effective in improving adhesive strength due to the formation of fine irregularities and a mechanical anchoring effect. However, since the copper oxide layer generally dissolves due to hydrolysis when it comes into contact with acid, it is necessary to avoid contact with acid after treatment and before adhesion. Further, even after bonding, when acid treatment is performed, there is a problem in that an undesirable phenomenon occurs in that the oxide layer at the bonding interface exposed at the inner surface of the hole penetrating the bonding surface or at the end of the cut surface is lost. As a method for solving this acid resistance problem, Japanese Patent Publication No. 11479/1983 describes that cupric oxide is converted into metallic copper using an alkaline reducing solution.

[Problem to be solved by the invention]

In the above conventional technology, the cupric oxide coating is reduced using an alkaline reducing agent solution, but this alkaline solution has the problem of being difficult to clean after immersion and easily corroding the resin. be.

An object of the present invention is to provide a method for adhering copper and resin that has good acid resistance and sufficiently high adhesion strength, and is particularly suitable for lamination adhesion of multilayer printed wiring boards that require high reliability. Another object of the present invention is to provide a method for bonding with resin.

[Means to solve the problem]

In order to achieve the above object, the method of bonding copper and resin by heat compression bonding includes a step of forming a copper oxide layer on the copper surface, and an acidic solution having a pH of 7.0 or less. This method includes a step of reducing copper to metal using a reducing solution.

[Effect]

As a result of various studies, we have found that by forming a copper oxide layer on the copper surface and then reducing it to metallic copper using an acidic reducing solution that does not dissolve the copper oxide layer, we have achieved good acid resistance and adhesive strength. We discovered that it is possible to achieve this. Furthermore, since an acidic reducing solution was used, the water washing effect after immersion was excellent, and it was confirmed that the resin layer was not attacked. As a method for forming the copper oxide layer, it is preferable to use an aqueous solution containing an oxidizing agent.

In order to reduce the formed copper oxide layer to metal, it is preferable to use an acidic solution containing a mixture of at least one type of amine borane represented by the general formula % CH, and a boron-based chemical.

〔Example〕

Hereinafter, the present invention will be explained by taking lamination adhesion of a multilayer printed wiring board as an example.

1) The copper surface of the glass cloth-containing polyimide resin copper-clad laminate was coated with CuCl2.・2H,050)/Q HcQ (36%) 500)/Q humidity temperature
Etching was performed by immersing it in an aqueous solution at 40°C for 1 minute.

2) Next, after washing with water, NαCQO□ 30? IQN cL3PO
, ·12H,05t/QNcLOH10tIQ It was immersed in an aqueous solution at a temperature of 75°C for 2 minutes to form a copper oxide layer.

3) After washing with water Dimethylamine borane 62/Q Boric acid 10p/QPH6,01 Temperature 45℃ After treatment with an aqueous solution of for 2 minutes, the oxide layer was reduced.

4) After washing the copper-clad laminates treated as above and drying them, they were laminated through a prepreg made of glass cloth impregnated with polyimide resin, and heated to 20 kgf/a+f at 170"C.
The adhesive was applied for 90 minutes.

The adhesion between the copper foil laminated and bonded in this way and the polyimide resin of the prepreg is good, and the beer strength is 1.2 kgf.
/am.

In addition, prior to lamination bonding, the copper clad laminate after reduction treatment is
: Even when immersed in hydrochloric acid of 1, no discoloration or dissolution of the 1 surface treatment layer was observed. Furthermore, after multilayer adhesion, through-holes were opened and immersed in 1:1 hydrochloric acid, but no acid seepage through the through-hole walls or discoloration of the adhesive layer was observed even after immersion for more than 3 hours.

Furthermore, since the reducing solution is acidic, the water washing effect after treatment is excellent, a clean surface can be easily obtained, and workability is good.

It was also noted that it did not attack the resin layer of copper-clad laminates.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to perform good adhesion while avoiding the problem of acid resistance before and after adhesion.

In addition, it has an excellent cleaning effect on the copper surface, has good workability, and has the effect of not corroding the resin layer.

Claims (1)

[Claims] 1. In the method of bonding copper and resin by heat compression bonding,
Adhesion of copper and resin, comprising a step of forming a copper oxide layer on a copper surface, and a step of reducing the formed copper oxide layer to metallic copper with an acidic reducing solution having a pH of 7.0 or less. Method.