Methods of selectively filling apertures
US6066889A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 1998 |
| Grant date | May 23, 2000 |
| Priority date | — |
| Expiry date | Sep 22, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/0278
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A novel method of filling apertures in substrates, such as through holes, is provided. The method utilizes a photoimageable film, and comprises the following steps: applying a photoimagable, hole fill film over the apertures; reflowing the hole fill film to flow into the apertures; exposing the hole fill film to actinic radiation, preferably ultraviolet light, through a phototool, which preferably has openings slightly larger than the diameter of the apertures; then at least partially curing the hole fill film; and developing the hole fill film to remove the unexposed hole fill film. An advantage of the present method is that the apertures may be selectively filled. After the apertures are filled, the hole fill film is cured, preferably by baking. Thereafter, the substrate is preferably subjected to further processing steps; for example, nubs of cured hole fill film are preferably removed. If desired, the substrate is circuitized. If desired, features are gold plated, such as for example, electrolessly gold plated. The hole fill film preferably has solids which comprise 0 to about 20% of a thixotrope and about 80% to about 100% parts of an epoxy resin system; the epoxy resin system…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.