US 4,931,148 AGranted

Method for manufacture of printed circuit boards

AssigneeMacDermid, Incorporated

InventorsPeter E. Kukanskis, Harold Rhodenizer

Life of this patent

Estimating the term…

Loading patent…

Abstract

Printed circuit boards containing thru-holes requiring metallization are manufactured by first applying to the board material an alkaline strippable resist in a predetermined desired pattern, thereafter applying material catalytic to subsequent metallization, thereafter treating the board with an aqueous alkaline solution to remove catalytic material from resist surfaces without adversely affecting the catalyst at non-resist areas, and then metallizing the non-resist areas. The ability to preliminarily apply the resist pattern before catalyst application, metallization, etc., yet prevent metallization of the resist, enables the manufacturing process to proceed straight through the activation, metallization, etc. steps without need for interruption for resist application.

A method for metallizing thru-holes formed in a metal-clad printed circuit board substrate material and for providing at the same time additional metallization of selected metal-clad surfaces of said metal-clad printed circuit board substrate material, comprising the steps of:

(a) providing a metal-clad printed circuit board substrate material having one or more thru-holes therein;
(b) applying a resist which is strippable in aqueous alkaline medium to selected surfaces of said metal-clad printed circuit board substrate material in a predetermined pattern to define those surfaces areas, over which resist is applied, where additional metallization is not desired;
(c) thereafter contacting said metal-clad printed circuit board substrate material, having said patterned resist thereon, with a conditioner;
(d) thereafter contacting said conditioned metal-clad printed circuit board substrate material, having said patterned resist thereon, with a microetchant;
(e) thereafter contacting said conditioned and micro-etched metal-clad printed circuit board substrate material, having said patterned resist thereon, with catalytic species which promote metallization, resulting in the provision of said catalytic species on thru-hole surfaces, resist surfaces and the surfaces of said metal-clad printed circuit board substrate material not covered by said resist;
(f) thereafter contacting at least said resist surfaces of said metal-clad printed circuit board substrate material with an aqueous alkaline deactivating solution under conditions which substantially inactivate said resist surfaces to metallization without substantially removing the resist surfaces and without inactivating said thru-hole surfaces and the surfaces of said metal-clad printed circuit board substrate material not covered by said resist;
and
(g) thereafter immersing said metal-clad printed circuit board substrate material, having said patterned resist thereon, in a metallizing solution effective to metallize said thru-hole surfaces and the surfaces of said metal-clad printed circuit board material not covered by said result, with substantially no metallization occurring on said resist surfaces.

5 more elements

Facts

Application

07/250,991Filed 27 Sep 1988 · continuation

Priority

6 Aug 1986

Granted

5 Jun 1990

Term ends

Not estimatedThe source records don’t support an estimate.

Classification16 codes

C25D 5/56
Electroplating of non-metallic surfaces: of plastics
H05K 3/108
In which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern: by semi-additive…
H05K 3/181
Using precipitation techniques to apply the conductive material: by electroless plating
H05K 3/184
Characterised by the patterning method: using masks

Abstract

Claims9