Method and apparatus for imaging surface topography of a wafer
US5953115A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1997 |
| Grant date | Sep 14, 1999 |
| Priority date | — |
| Expiry date | Oct 28, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/552
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for imaging surface topography is based on Total Internal Reflection (TIR) and is particularly useful for imaging surface topography of wafers used in the manufacture of integrated circuits. This surface topography includes scratches, which are more localized, and dishing, which is a gentle dip over a larger area. In practice, a wafer is placed with the surface of interest in close contact with a prism or other internal reflection element (IRE). Light of suitable wavelength is incident at a suitable incident angle through the IRE of suitable refractive index in order to allow total internal reflectance at the surface of the IRE in close contact with the wafer surface. The reflected beam is then imaged to give a map of the location and dimensions, and some information on the depth, of the various surface features on the wafer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.