Method and apparatus for determining substrate layer thickness during chemical mechanical polishing
US6247998A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 25, 1999 |
| Grant date | Jun 19, 2001 |
| Priority date | — |
| Expiry date | Jan 25, 2019 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB24B49/04
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A chemical mechanical polishing apparatus includes a platen to support a polishing pad, and a polishing head to hold a substrate against the polishing pad during processing. The substrate includes a thin film structure disposed on a wafer. A first optical system includes a first light source to generate a first light beam which impinges on a surface of the substrate, and a first sensor to measure light reflected from the surface of the substrate to generate a measured first interference signal. A second optical system includes a second light source to generate a second light beam which impinges on a surface of the substrate and a second sensor to measure light reflected from the surface of the substrate to generate a measured second interference signal. The second light beam has a wavelength different from the first light beam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.