Disco speeds up SiC wafer slicing
Disco Corporation, based in Japan, has developed a laser ingot slicing method called Kabra ( Key Amorphous-Black Repetitive Absorption) for high-speed production of SiC wafers.
The existing methods for slicing wafers from a SiC ingot typically use diamond wire saws. The processing time is long due to the high rigidity of SiC. Moreover, the number of wafers produced is small due to the amount of material lost in the slicing sections.
The Kabra process forms a flat light-absorbing separation layer at a specified depth by irradiating a continuous, vertical laser from the upper surface of the SiC and creating wafers.
According to Disco, this laser slicing method relies on the fact that SiC can be decomposed by a focused laser and separated into amorphous silicon and carbon; and that the light absorption coefficient of the black amorphous material is approximately 100,000 times larger than that of SiC.
Existing processes require around two hours to slice a wafer from a 4-inch SiC ingot (two to three days for one ingot). In contrast, the Kabra process requires only 25 minutes to slice a wafer (around 18 hours for one ingot). In addition, this process only takes around 30 minutes to slice a wafer from a 6-inch SiC ingot even though the existing process requires over three hours.
