Process for photoimaging a three dimensional printed circuit substrate
US5001038A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 1987 |
| Grant date | Mar 19, 1991 |
| Priority date | — |
| Expiry date | Nov 16, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/056
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Printed circuit patterns are photolithographically defined on a three dimensional "projection" surface (204) of a printed circuit substrate (202) using a projection image aligner and a photomask (210) having a planar image (210A). The geometry of the projection is restricted such that the slope of the projection surface, as measured at any point on the projection surface and relative to a reference plane which is parallel to the focal plane of the projection image aligner, is less than 90 degrees. A solution of photoresist includes a photoresist solvent, a fluorosurfactant and an aromatic hydrocarbon solvent, and is preferably sprayed over the projection surface. In one method of manufacture, the printed circuit substrate is moved from one position to another during the exposure of the photoresist layer (206). In another method, after a first portion of the projection surface is exposed by a first photomask (502), a second photomask (504) is substituted and the remainder of the projection surface exposed. In still another method, a photomask having a plurality of planar images (604A, 604B and 606A) each image being positioned parallel to the others but separated by a small distance…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.