Direct electroplating of through holes
AssigneeInternational Business Machines Corporation
InventorsBernd K. Appelt, Perminder Bindra, Robert D. Edwards, James R. Loomis, Jae M. Park, Jonathan D. Reid, Lisa J. Smith, James R. White
Life of this patent
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Abstract
Substantially nonconductive or semiconductive surfaces of through holes can be electroplated directly, without an intervening non-electrolytic metallization, by a stepwise process which includes the application to the through holes of a polyelectrolyte surfactant in solution in combination with the application of a conductive metal containing material.
Claims18
A method for the direct electroplating of the walls within a through hole in a metal clad dielectric laminate, without an electroless plating step, the method comprising the steps of:
- providing at least one through hole in the metal clad laminate;
- cleaning away any drill smear;
- applying a solution of surfactant to the walls of the through hole;
- rinsing away any surfactant in excess of an amount useful to attract and promote adhesion of a metal-containing material to the wall of the through hole;
- applying a solution comprising metal containing material to the wall of the through hole;
- rinsing away any excess conductive metal-containing material from the hole so as to leave a quantity of the material in the walls sufficient to permit electroplating;
- and
- electroplating metal to a predetermined thickness on the wall of the through hole which has been rendered conductive by the metal containing material.
A printed circuit board defining at least one conductive through hole therein formed by the process comprising the steps of:
- providing at least one through hole within the metal clad laminate;
- cleaning away any drill smear;
- applying a solution of polyelectrolyte to the walls of the through hole;
- rinsing away any polyelectrolyte in excess of an amount useful to attract and promote adhesion of a metal-containing material to the wall of the through hole;
- applying a solution comprising metal containing material not including an electroless plating bath to the wall of the through hole;
- rinsing away any excess conductive metal-containing material from the hole so as to leave a quantity of the material in the walls sufficient to permit electroplating;
- and
- electroplating metal to a predetermined thickness on the wall of the through hole which has been rendered conductive by the metal containing material.
Dependencies are inferred from the claim text.