Enhanced resolution wafer thickness measurement system
US5420803A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 18, 1992 |
| Grant date | May 30, 1995 |
| Priority date | — |
| Expiry date | Nov 18, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B7/345
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus involving the use of a thickness measurement probe having a predetermined resolution to measure the thickness of a wafer over a two-dimensional area of the wafer, the method including sampling the measured thickness of the wafer with the probe to generate an image of the two-dimensional area of the wafer, the image being a two-dimensional array of measurements, each measurement representing a measurement of the thickness of a different region of the two-dimensional area, the two-dimensional array of measurements being represented by a measured column tensor; and left multiplying the measured column tensor by a reconstruction tensor T to obtain an estimate of a desired measurement column tensor, where the reconstruction tensor T is equal to R.sub.dm R.sub.mm.sup.-1, R.sub.dm being a cross-covariance tensor computed for d, a desired measurement column tensor, and m, the measured column tensor, and R.sub.mm being an auto-covariance tensor computed for m, and wherein the estimate of a desired measurement column tensor represents an estimate of measurements that would be obtained from a hypothetical probe assembly having a different resolution from the first menti…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.