Method for forming electrical connection to the inner layers of a multilayer circuit board
US5472735A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 8, 1994 |
| Grant date | Dec 5, 1995 |
| Priority date | — |
| Expiry date | Dec 8, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S204/07
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention relates to a method for selectively electroetching a metal from an electrical device having the steps of: immersing the electrical device in an etching solution; immersing a cathode in the etching solution; applying an etching potential to a preselected area of the metal; and maintaining a passivation potential at the metal to remain unetched. The metal to remain unetched is not electrically connected to the preselected area and the passivation potential does not equal the etching potential. The present invention further relates to a method of forming an electrical connection to the inner layers of a multilayer circuit board having a copper foil surface layer and copper containing inner layers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.