The Chemical Stain Inspection of Polysilicon Solar Cell Wafer by the Fuzzy Theory Method

Abstract

This study proposed an automatic optical inspection (AOI) technique to improve the inspection of chemical stains on solar wafers. Poly-silicon solar cell wafers were inspected for chemical stains, and the inspection was rapid and stable. The system used a laser-reflection-point-based AOI method for solar wafer chemical stain inspection. Based on the fuzzy theory, the image binarization algorithm could efficiently filter irrelevant image information, and the back-propagation method was also utilized to determine if the image was stained. The inspection algorithm integrated fuzzy theory and the back-propagation method in order to shorten the comparison time and quickly find the target. The experiment proved that the validity of the proposed method could achieve a recognition rate of 98% from among 1000 images.

Keywords:

• Solar wafer
• Laser-reflection-point based AOI method
• Chemical stain inspection
• Fuzzy theory
• Back-propagation
• Image binarization algorithm
• Stain recognition

Acknowledgements

This work was sponsored by the National Science Council under grant number NSC 101-2221-E-035 -039 -MY2 and the help of Mosel Vitelic Inc.