Circuitization of polymeric circuit boards with galvanic removal of chromium adhesion layers
US5126016A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 1, 1991 |
| Grant date | Jun 30, 1992 |
| Priority date | — |
| Expiry date | Feb 1, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K3/388
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Disclosed is a method of fabricating a microelectronic package, especially a microelectronic package having copper circuitization on a dielectric substrate. The method includes the steps of depositing a chromium adhesion layer on the dielectric substrate, depositing a copper seed layer on the chromium adhesion layer, depositing photoresist on the copper seed layer, imaging and developing the photoresist, and forming a pattern of copper circuitization on the selected portions of the send copper layer. The chromium adhesion layer material is removed from the dielectric substrate by contacting the chromium adhesion layer with aqueous sulfuric acid electrolyte, while maintaining the chromium adhesion layer electrolytically in series with a counterelectrode, and maintaining the chromium adhesion layer anodic with respect to the counterelectrode. The chromium adhesion layer material is oxidized to soluble Cr.sup.+3, while substantially avoiding formation of Cr.sup.+6.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.