Debris Reduction in GaAs Wafer Dicing Process
Keyword: Debris, Cutting fluid, Plasma
Lots of debris is usually generated during the GaAs wafer dicing process leading to chip defects and scum on the chip and ultimately, low wafer yield. In this study we combine the cutting fluid with an appropriate water pressure to make the GaAs debris easy to be carried away from the chip surface. Furthermore, we increase the DI water cleaning time after a sawing process to ensure the chip cleanness. An oxygen plasma process after DI water cleaning is also implemented to further clean any remaining amount of debris from GaAs chips. The wafer re-work rates are significantly reduced from 60 – 70% to 1 - 3%, resulting in high wafer yield and shortened backend processing time.