Selective metal etch technique
US4374869A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 18, 1982 |
| Grant date | Feb 22, 1983 |
| Priority date | — |
| Expiry date | Jan 18, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/1147
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of forming a flexible printed wiring board having a metal substrate includes the steps of etching through-holes in the metal substrate by means of an etch resistant ferro electric mask placed over the substrate and employing a viscous sealant such as polyethylene or polypropylene glycol between the mask and the substrate. The mask is held to the substrate with the sealant therebetween by means of a magnetic field. The substrate is then treated with a ferric chloride etch solution to etch away the desired through-holes in the metal substrate. Thereafter, the substrate may be coated with a polymeric coated by means of fluidized bed or electrostatic coating techniques as taught in the prior art.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.