Polyimide composite coverlays and methods and compositions relating thereto
US7579134B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 2005 |
| Grant date | Aug 25, 2009 |
| Priority date | — |
| Expiry date | Apr 22, 2026 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31725
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention is directed to coverlay compositions derived from two-layer polyamic acid-based composites having a cover layer and adjacent thereto an adhesive layer wherein the cover layer comprises polyamic acid and other additives allowing the composition to be photosensitive and aqueous base developable, and where the adhesive layer can form a polyimide having a glass transition temperature between 170 and 250° C. The two-layer coverlay compositions of the present invention are used to encapsulate metal circuit traces formed on a flexible printed circuit base substrate. These two-layer compositions are particularity useful due to having an overall in-plane CTE between 10 and 40 ppm/° C. a range that is useful in avoiding unwanted curling of a flexible printed circuit when used as a polyimide-based coverlay material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.