JPH0227794A - Drilling of multilayer wiring board - Google Patents

Abstract

PURPOSE:To prevent the production of smears by drilling a laminated board in a condition in which it is immersed in liquid. CONSTITUTION:A patch 4 made of bakelite is applied to a laminted board 3 and fixed on a metal vessel 1 having fixing pins 2. Solution in which interface active agent is dissolved is added so that the surface of the laminated board 3 is immersed entirely. Next a hole is bored by a drill. As the result the solution enters the hole, the heat generated by rotating friction of a drill blade is rapidly removed and the melting of resin can be prevented. Thereby the production of smears can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to through-holes and via-holes necessary for electrically connecting conductor wirings located above and below across the t@edge film layer in an organic multilayer wiring board. Confucius such as this is about method.

[Conventional technology]

Holes, which are essential for manufacturing multilayer wiring boards, are generally made by stacking several multilayer boards and using an NC drill, etc.
At this time, the multilayer board is kept in the atmosphere.

[Problem to be solved by the invention]

When drilling holes using the above method, the rotational friction of the drill blade generates heat, softens or melts the resin that makes up the laminate, and moves and adheres to the surface or end surface of the conductor pattern.
The occurrence of so-called smear is unavoidable, and it is necessary to remove the smear before metal plating. Smear removal usually involves a wet method using concentrated sulfuric acid, chromic acid, etc., or a dry method using plasma, but both methods are complicated, and if the smear removal is insufficient, conduction through the holes may be lost. This results in defects and impairs the reliability of the final product.Therefore, a method is desired that does not generate smear.

[Means to solve the problem]

That is, the present invention provides a multilayer wiring board characterized in that when drilling holes in a laminate with metal foil pasted on both sides using an NC drill or the like, the laminate is immersed in a liquid. Komei is a method, and in particular, the Komei method is characterized in that the laminate is a resin laminate.

The liquid used here preferably has a boiling point lower than the softening temperature of the resin, is inert to the resin, and has low toxicity. Specifically, water and various organic fluorine compounds can be used. .

In some cases, a suitable surfactant may be used to
It is also a preferred embodiment to add about 10%.

Of course, the organic laminate to which the present invention is directed is made by laminating the required number of sheets of material in which glass cloth, Kevlar fiber, paper, cloth, etc. are impregnated with, for example, phenol resin, epoxy resin, unsaturated polyester resin, polyimide resin, etc. and then pressing them. It is a laminated board made by molding.

[Effect]

In the present invention, as described above (when drilling a hole in a laminate plate, by immersing it in liquid, the liquid enters the hole and quickly removes the heat generated by the rotational friction of the drill blade, It prevents the resin from softening or melting and prevents the occurrence of smear. [Example] Five glass cloth epoxy laminates with a thickness of 0.3 cm (G-10FR) with 70 μΦ copper foil pasted on both sides. manufactured by Noichi Prex Oak Co., Ltd.) with a thickness of 0.05a++e (CLGF04 Centiuri).
A 10-layer laminate with a thickness of about 3.2 was obtained by press-molding 5 sheets per layer (manufactured by Laminator) by a conventional method.

As shown in Figure -■, a Bakelite plate (■) was applied to the laminated plate (■), and it was fixed in a metal container (■) having a fixing bottle (■).

Add to this 0.3% surfactant (Emarl 10 Needle)
City water containing Kao (manufactured by Kao Corporation) was added to the plate so that the surface of the plate was completely immersed.Then, a hole with a diameter of 0.8 mm and 0.3 m was penetrated using a drill.

[Comparative example]

Using the same laminate as in the example, the holes were penetrated in the atmosphere without being immersed in water.

Next, the through-hole portions of the N-laminated plates obtained in Examples and Comparative Examples were cut, and the presence or absence of smear on the cut surfaces was observed. As a result of observation, in the comparative example, the diameter was 20% with 0.8 diameter, and 0.8%.
Smears requiring removal were generated in 50% of cases with a 3M diameter.

In the examples, no smear requiring removal occurred for any pore size.

〔Effect of the invention〕

As explained above, the method of the present invention is extremely effective in preventing the formation of smear, which is a problem in the process, since the pores are essential in the production of organic multilayer wiring boards.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of the state of implementation of the present invention. Figure-1

Claims (2)

[Claims] (1) A method for drilling holes in a multilayer wiring board, characterized in that when drilling holes in a laminate with metal foil pasted on both sides using an NC drill, etc., the holes are drilled while the laminate is immersed in a liquid. . (2) The method for drilling holes according to claim 1, wherein the laminate is a resin laminate.