Patent · US Expired

Film thickness-measuring apparatus

US4872758A · kind A · utility

71Cited by
4References
10Claims
0Family size

Assignee

Inventors

Key dates

Filing dateJul 22, 1988
Grant dateOct 10, 1989
Priority date
Expiry dateJul 22, 2008

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG01N21/211
  • WIPO fieldMeasurement
  • WIPO sectorInstruments

Abstract

Circularly polarized light caused to be incident on a film surface is converted into three light beams by optical flats to obtain electrical signals corresponding to the intensities of the respective light beams. Two ellipsometric parameters .psi. and .DELTA. are claculated from these three electrical signals.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.