Method for producing semiconductor wafers with low light scattering anomalies
US5629216A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 27, 1996 |
| Grant date | May 13, 1997 |
| Priority date | — |
| Expiry date | Feb 27, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/127
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A monitor wafer used to determine the cleanliness of a wafer fabrication environment requires a surface having a minimum of light scattering anomalies so that contamination deposited by the environment is not confused with light scattering anomalies initially on the monitor wafers. In the present invention, ingots of a single-crystal semiconductor are grown at a reduced pull rate and wafers produced from the ingot are annealed within a preferred temperature range that varies with the pull rate to produce wafers having reduced light-scattering anomalies on their surfaces. The number of light-scattering anomalies increases at a slower rate upon repetitive cleaning cycles than does the number of light-scattering anomalies of prior art wafers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.