Wafer test system touted

HUMAN FACTOR REMOVED::The process of quality control for IC systems could reduce testing costs by 30 to 50 percent and shorten testing time to 20 minutes

By Chen Wei-han  /  Staff reporter

Wed, Sep 23, 2015 - Page 4

The National Applied Research Laboratories (NARL) said it has developed a fully automatic optical inspection system to test integrated circuits and wafers to replace human technicians on production lines, with the system potentially to open up a new technology roadmap for the semiconductor industry.

Traditional IC testing uses a chip sorter to test electrical conductivity and sort out non-passing circuits, but the backs of wafers and wafer scribe lines could only be inspected for defects manually by technicians using microscopes, Instrument Technology Research Center director Yeh Che-liang (葉哲良) said.

However, the inspection process is time consuming and can be blighted by misjudgements due to fatigue, while flipping a wafer to examine the back for defects and manually removing defective segments risks mishaps due to human error, Yeh said.

In coordination with Epistar Corp, Taiwan’s No. 1 LED chipmaker, and semiconductor advanced packaging company Gallant Micro Machining Corp, NARL developed the optical system, which uses pattern recognition algorithms and linear array technology capable of producing a complete wafer map to analyze every circuit in one go, he said.

The system integrates software and a robotic arm to pick out defective sectors anywhere on a wafer, while searching for possible errors arising from the manufacturing process, he said.

By replacing technicians with automation, the system could reduce testing costs by 30 to 50 percent and shorten testing time to 20 minutes, a 50 to 70 percent improvement, he said, adding that the system could boost the precision rate from 90 percent to more than 99 percent compared with existing optical inspection systems.

“The system was developed locally and could improve the autonomy of the semiconductor industry, as Japanese optical devices have traditionally been preferred to test IC products,” Yeh said.

Previous systems could only take a single image at a time at a set interval, which would delay the manufacturing process and required technicians to re-examine each wafer, he said.

Gallant Micro Machining general manager Hsu Hung-ming (許鴻銘) said a fully automated system would become standard in the industry and could possibly change the entire manufacturing process, paving the way to restructure the industry’s operation model.

The system has been adopted by domestic and South Korean companies, Hsu said.