SUMMARY:
UCLA researchers in the Department of Electrical and Computer Engineering have developed a method that utilizes a hybrid dispersion laser scanner for fast quality control of particles on silicon wafers to reduce wafer manufacturing cost.
BACKGROUND:
Web inspection, also known as surface inspection, is a method widely used for evaluation of products during manufacturing. Surface inspection applications include quality control, defect detection, and dimensional metrology in the production of thin films for electronic devices. Organic light-emitting diodes (OLED) and thin film transistors (TFT), for example, heavily rely on highly uniform, nano-scale films for proper functionality. To maintain pace with the demand for production of thinner films for electronic devices high-speed quality control methods are required. Current surface inspection methods utilize a line scan camera with a white light source and a laser scan with a single -pixel photodetector. However, the scan for dust or other defects occurs via continuous line scan and is thus not capable of fast object inspection. Therefore, there is a need for a method that will speed up inspection of manufactured thin films to keep up with the strong market demand of electronics and other devices.
INNOVATION:
UCLA researchers in the Department of Electrical and Computer Engineering have developed a method for rapid surface inspection of thin films by using a hybrid dispersion laser scanner (HDLS). The HDLS combined spatially and temporally dispersive elements with a broadband mode-locked laser. The method allowed ultrafast laser scanning of impurities 1000 times faster than currently employed technologies. The method was deployed by inspection of dust particles in real time on silicon wafers that ranged from 40-400 µm. The developed method could help to meet the market needs for new electronics that require thin films.
POTENTIAL APPLICATIONS:
• Silicon wafer inspection
• Liquid crystal display panel inspection
• Fabric and paper inspection
• Thin film inspection
ADVANTAGES
• Ultrafast scanning of imperfections
• Broadband mode-locked laser
• Hybrid dispersion laser scanner usage
• Wide range of scanning
DEVELOPMENT TO DATE:
First successful demonstration by detection of dust particles and defects in silicon wafers.
RELATED PAPERS:
Chen, H.; Wang, C.; Yazaki, A.; Kim, C.; Goda, K.; Jalali, B. “Ultrafast web inspection with hybrid dispersion laser scanner”. Applied Optics. (2013) 52, 4072-4076.