Method and apparatus for CMP end point detection using confocal optics
US6307628A · kind A · utility
43Cited by
5References
19Claims
0Family size
Assignee
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Key dates
| Filing date | Aug 18, 2000 |
| Grant date | Oct 23, 2001 |
| Priority date | — |
| Expiry date | Aug 18, 2020 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB24B49/12
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
End point detection during a CMP process on a semiconductor wafer employs confocal optics to increase signal-to-noise ratio near the end point. The use of confocal optics for sensing reflected light from the wafer surface exhibits greater selectivity where intermediate layers of metal are present in the wafer. A laser diode is used as a light source to examine the wafer surface. Light reflected back to the laser diode reduces its power state, and this power state is sensed by a current detector which outputs a signal representative of reflected light intensity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.