Method for reducing wafer shape and thickness measurement errors resulted from cavity shape changes
US9121684B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 15, 2013 |
| Grant date | Sep 1, 2015 |
| Priority date | — |
| Expiry date | Mar 23, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B9/02027
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods and systems for reducing wafer shape and thickness measurement errors resulted from cavity shape changes are disclosed. Cavity calibration process is performed immediately before the wafer measurement. Calibrating the cavity characteristics every time the method is executed reduces wafer shape and thickness measurement errors resulted from cavity shape changes. Additionally or alternatively, a polynomial fitting process utilizing a polynomial of at least a second order is utilized for cavity tilt estimation. High order cavity shape information generated using high order polynomials takes into consideration cavity shape changes due to temperature variations, stress or the like, effectively increases accuracy of the wafer shape and thickness information computed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.