Chapter

Knowledge-Based Intelligent Information and Engineering Systems

Volume 4252 of the series Lecture Notes in Computer Science pp 545-552

Adaptive Nonlinearity Compensation of Heterodyne Laser Interferometer

  • Minsuk HongAffiliated withSungkyunkwan University
  • , Jaewook JeonAffiliated withSungkyunkwan University
  • , Kiheon ParkAffiliated withSungkyunkwan University
  • , Kwanho YouAffiliated withSungkyunkwan University

Abstract

With its outstanding ultra-precise resolution, the heterodyne laser interferometer systems are commonly used in semiconductor manufacturing industry. However, the periodical nonlinearity error caused from frequency-mixed cross talks limits the accuracy in nanometer scale. In this paper to improve the accuracy of laser interferometer system, we propose an adaptive nonlinearity compensation algorithm using RLS (recursive least square) method. As a reference signal, the capacitance displacement sensor mounted on a linear piezo-electric transducer gives a feedback information on how to transform the elliptical phase into a circular one.