Endpoint detection with light beams of different wavelengths
US6190234A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 27, 1999 |
| Grant date | Feb 20, 2001 |
| Priority date | — |
| Expiry date | Apr 27, 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 two optical systems which are used serially to determine polishing endpoints. The 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. The 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.