High quality and high speed cutting of 4H-SiC JFET wafers including PCM structures by using Thermal Laser Separation

Abstract

The silicon carbide (SiC) market is gaining momentum hence productivity in device manufacturing has to be improved. The current transition from 100 mm SiC-wafers to 150 mm SiC-wafers requires novel processes in the front-end as well as the back-end of SiC-chip production. Dicing of fully processed SiC-wafers is becoming a bottleneck process since current state-of-the-art mechanical blade dicing faces heavy tool wear and achieves low throughput due to low feed rates in the range of only a few mm/s. This paper presents latest results of the novel dicing technology Thermal Laser Separation (TLS) applied for separating SiC-JFETs. We demonstrate for the first time that TLS is capable of dicing fully processed 4H-SiC wafers, including back side metal layer stacks, process control monitoring (PCM), and metal structures inside the dicing streets with feed rates up to 200 mm/s. TLS thus paves the way to efficient dicing of 150 mm SiC-wafers.