Apparatus and methods for detecting thickness of a patterned layer
US6489624B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 20, 1998 |
| Grant date | Dec 3, 2002 |
| Priority date | — |
| Expiry date | Jul 20, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/0683
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus and methods are disclosed that measure the thickness of a layer on a workpiece such as a semiconductor wafer, especially as the layer is undergoing a process such as polishing to achieve planarization of the layer. The apparatus comprises a probe light optical system that directs a beam of probe light to be incident on a surface of the layer, and produce a signal light from reflection of the probe light from or transmission of the probe light through the layer. A light detector retrieves and detects sufficient wavelengths of the signal light to produce a corresponding electronic signal encoding data regarding the intensity at various wavelengths of the signal light. At least one of the following is monitored: appearance or disappearance of maxima or minima in a spectrum of intensity or transmittance of the signal light, a change in wavelength at which a maximum or minimum is located in the spectrum, and change in intensity at a particular wavelength at which a maximum or minimum is located in the spectrum. The apparatus can be included with a polishing apparatus.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.