Method of providing printed circuits
First Claim
1. In a method of preparing a printed circuit board comprising the steps of chemically catalyzing the surface of an insulating material for the electroless deposition of metal, electrolessly deposited a layer of copper on said catalyzed surface, providing a layer of masking material on selected areas of the electrolessly deposited copper layer to leave an area of exposed copper in a desired pattern of conductor lines, building up an additional layer of copper on said exposed areas by electrolytic deposition, removing the layer of masking material and etching away the layer of electrolessly deposited copper from the previously masked areas, the improvement which comprises:
- (a) before removing said masking material, forming an etch-resistant protective layer of oxide on the surface of the exposed layer of electrolytically deposited copper;
(b) removing said masking material from the layer of electrolessly deposited copper; and
(c) etching away the electrolessly deposited copper from the previously masked areas, to provide a printed circuit board having the desired surface pattern of conductor lines with an etch-resistant protective oxide layer thereon.
2 Assignments
0 Petitions
Accused Products
Abstract
There is provided an improvement in the method of preparing printed circuit boards by chemically catalyzing the surface of an insulating material, electrolessly depositing a layer of copper thereon, masking selected areas of the copper layer not correspnding to the desired pattern of conductor lines, electrolytically depositing additional copper on the unmasked areas, removing the masking material and etching away the copper from the previously masked areas. The improvement comprises the steps of forming an etch-resistant protective layer of oxide on the surface of the electrolytically deposited copper layer before removing the masking material, then removing the masking material and etching away the electrolessly deposited copper from the previously masked areas.
19 Citations
12 Claims
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1. In a method of preparing a printed circuit board comprising the steps of chemically catalyzing the surface of an insulating material for the electroless deposition of metal, electrolessly deposited a layer of copper on said catalyzed surface, providing a layer of masking material on selected areas of the electrolessly deposited copper layer to leave an area of exposed copper in a desired pattern of conductor lines, building up an additional layer of copper on said exposed areas by electrolytic deposition, removing the layer of masking material and etching away the layer of electrolessly deposited copper from the previously masked areas, the improvement which comprises:
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(a) before removing said masking material, forming an etch-resistant protective layer of oxide on the surface of the exposed layer of electrolytically deposited copper; (b) removing said masking material from the layer of electrolessly deposited copper; and (c) etching away the electrolessly deposited copper from the previously masked areas, to provide a printed circuit board having the desired surface pattern of conductor lines with an etch-resistant protective oxide layer thereon. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification