Method for cleaning workpiece surfaces and monitoring probes during workpiece processing
US5958148A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 16, 1997 |
| Grant date | Sep 28, 1999 |
| Priority date | — |
| Expiry date | Jul 16, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/12
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The present invention provides methods and apparatus which permit the in-process, in-situ, substantially real time measurement of the actual thickness of a surface layer of a workpiece, e.g., a semiconductor wafer. A probe is disposed proximate the outer perimeter of a polishing pad on a CMP table such that the probe establishes optical contact with the wafer surface as a portion of the wafer extends beyond the outer perimeter of the polishing pad. A reflected signal received by the probe is analyzed to calculate the thickness of the surface layer. Alternatively, the reflective characteristics of the semiconductor layers may affect the nature of the reflected signal; changes in the reflected signal can be detected to indicate when a metallic layer has been removed from an oxide layer. In accordance with another aspect of the present invention, a nozzle assembly having a plurality of fluid outlets may be provided to apply a stream of deionized water at the surface under inspection to thereby remove excess slurry and debris from the local region of the workpiece being inspected. A second fluid nozzle may be provided to apply a stream of deionized water to the tip of the probe tip to …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.