Method and apparatus for measuring substrate layer thickness during chemical mechanical polishing
US6524165B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 23, 2000 |
| Grant date | Feb 25, 2003 |
| Priority date | — |
| Expiry date | Oct 23, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B9/02027
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The thickness of a layer on a substrate is measured in-situ during chemical mechanical polishing. A light beam is divided through a window in a polishing pad, and the motion of the polishing pad relative to the substrate causes the light beam to move in a path across the substrate surface. An interference signal produced by the light beam reflecting off the substrate is monitored, and a plurality of intensity measurements are extracted from the interference signal. Each intensity measurement corresponds to a sampling zone in the path across the substrate surface. A radial position is determined for each sampling zone, and the intensity measurements are divided into a plurality of radial ranges according to the radial positions. The layer thickness is computed for each radial range from the intensity measurements associated with that radial range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.