Semiconductor EPI on recycled silicon wafers
US5131979A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 21, 1991 |
| Grant date | Jul 21, 1992 |
| Priority date | — |
| Expiry date | May 21, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/959
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Disclosed is a method for transforming a rejected semiconductor product wafer, originally having epitaxial silicon on a low resistivity substrate, into a recycled EPI-on-silicon wafer targeted for reuse as a lower cost higher quality material suitable for new semiconductor product fabrication. The method comprises the steps of removing the old semiconductor product layers, rounding the edges of the wafer if necessary, polishing the wafer surface, thermally treating the wafer to drive lattice imperfections from the surface to create fresh inpurity getter sites in the wafer body, and introducing a new epitaxial silicon layer. The low cost feature is provided by the reuse of the original substrate wafer. The high quality feature is provided by the targeted redistribution of oxygen induced defects from the recycled substrate wafer surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.