Correction of PZT scanner errors using a phase compensation method in white-light phase-shifting interferometry

Area of Science:

• Optical metrology
• Surface characterization
• Manufacturing process control

Background:

• White-light phase-shifting interferometry (WLPSI) is crucial for surface profiling in industries like LCD and semiconductor manufacturing.
• Scanner movement irregularities introduce phase errors, degrading measurement accuracy and stability in WLPSI.
• Complete elimination of mechanical and electrical delays in scanner systems is challenging.

Purpose of the Study:

• To propose a novel method for correcting phase errors in WLPSI stemming from nonlinear scanner motion.
• To enhance the measurement accuracy and repeatability of WLPSI systems.
• To address the limitations of conventional phase correction techniques.

Main Methods:

• Development of a scanner position tracking system.
• Implementation of a phase correction algorithm: compensated peak detection and modified bucket algorithm.
• Experimental verification of the proposed method against conventional approaches.

Main Results:

• The proposed method effectively compensates for phase errors caused by irregular scanner movement.
• Experimental results demonstrate superior performance compared to traditional phase correction techniques.
• Significant improvements in both measurement accuracy and repeatability were achieved.

Conclusions:

• The novel scanner position tracking and phase correction method offers a robust solution for WLPSI.
• This technique enhances the reliability of surface profiling in demanding manufacturing environments.
• The compensated peak detection and modified bucket algorithm represents a significant advancement in optical metrology.