Apparatus and method for evaluating a wafer of semiconductor material
US6049220A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 10, 1998 |
| Grant date | Apr 11, 2000 |
| Priority date | — |
| Expiry date | Jun 10, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus and method uses diffusive modulation (without generating a wave of carriers) for measuring a material property (such as any one or more of: mobility, doping, and lifetime) that is used in evaluating a semiconductor wafer. The measurements are carried out in a small area, for use on wafers having patterns for integrated circuit dice. The measurements are based on measurement of reflectance, for example as a function of carrier concentration. In one implementation, the semiconductor wafer is illuminated with two beams, one with photon energy above the bandgap energy of the semiconductor, and another with photon energy near or below the bandgap. The diameters of the two beams relative to one another are varied to extract additional information about the semiconductor material, for use in measuring, e.g. lifetime.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.