Apparatus and method for characterizing semiconductor wafers during processing
US6182510A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 2000 |
| Grant date | Feb 6, 2001 |
| Priority date | — |
| Expiry date | May 10, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/2698
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus and method are disclosed for characterizing semiconductor wafers or other test objects that can support acoustic waves. Source and receiving transducers are configured in various arrangements to respectively excite and detect acoustic waves (e.g., Lamb waves) in a wafer to be characterized. Signals representing the detected waves are digitally processed and used to compute a measurement set correlated with the waves' velocity in the wafer. A characterization sensitivity is provided that describes how different wafer characteristics of interest vary with changes in the propagation of the acoustic waves. Using the characterization sensitivity and measurement sets computed at a setup time when all wafer characteristics are known and one or more process times when at least one of the characteristics is not known the perturbation in wafer characteristics between the setup and the process times can be determined. Characterization accuracy is improved by a wafer calibration procedure wherein measurement offsets from known conditions are determined for each wafer being characterized. An apparatus and technique are disclosed for correcting for anisotropy of acoustic wave veloci…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.