Process for preparing printed circuits
AssigneeFormica International Limited
InventorsAnthony James Shaul, Edward Russell Wood
Life of this patent
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Abstract
The invention relates to printed circuits and to insulating substrates useful in their preparation. The invention provides a process for preparing an insulating substrate by curing a layer of an etchable synthetic rubber and a thermosettable resin to give a selectively etchable layer, superimposing the layer on a fibrous sheet or web impregnated with a thermosettable resin and consolidating the assembly as produced by heating under pressure. Printed circuits prepared from the insulating substrates have superior peel strength.
Claims5
A process for preparing a printed circuit comprising an insulating substrate carrying a metal layer or pattern, the process consisting essentially of the steps of:
- 1. substantially fully curing a mixture consisting essentially of (a) an etchable synthetic rubber polymer which, in the substantially fully cured state, is attackable by a chemical etchant solution and (b) a first thermosettable resin, to give a selectively etchable and substantially non-adhesive layer consisting essentially of said rubber and the thermoset resin,
- 2. superimposing said layer on a fibrous substrate which consists essentially of at least one sheet or web, said sheet or web being impregnated with a second thermosettable resin,
- 3. consolidating the assembly so produced and curing said second thermosettable resin by heating under pressure to provide an insulating substrate comprising said selectivity etchable layer on the fibrous substrate,
- 4. chemically etching the surface of said selectively etchable layer, and
- 5. forming a metal layer or pattern on the etched surface by electroless deposition.
Dependencies are inferred from the claim text.