Non-destructive method of measuring the thickness of a semiconductor wafer
US6937351B1 · kind B1 · utility
2Cited by
10References
20Claims
0Family size
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Key dates
| Filing date | Nov 4, 2002 |
| Grant date | Aug 30, 2005 |
| Priority date | — |
| Expiry date | Jun 7, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B9/04
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The thickness of a semiconductor wafer is non-destructively measured using infrared (IR) microscopy. The wafer is placed on a stage. A distance between the stage and a detector is then varied so that a first image of the wafer is focused on the detector. When focused, a first separation distance is measured. The distance between the stage and the detector is again varied so that a second image is focused on the detector. When again focused, a second separation distance is measured. The difference between the first and second separation distances is then determined and multiplied by the refractive index of light in silicon.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.