Wafer thinning has been used for many years in the microelectronic industry for a wide range of applications. In the last years, wafer thinning process has become more critical than ever due to the demand of ultra-thin and high-performance components, and consequently requiring better process control solutions. This is even more critical for power semiconductor devices such as MOSFET or IGBT where the backside of the die play an active role.
Back grinding is the most popular process method used to reduce the wafer thickness as it is a low cost and high speed technic. However, the mechanical stress and heat applied during this process can generate some damages. These damages need to be carefully understood and control as they impact the fab manufacturing yield as well as the performance and reliability of the final device.
UnitySC developed new inspection technics compliant with high volume manufacturing allowing to perform the full wafer characterization after back grinding and after wafer metallization. The 4See Series with a combination of Deflector module and Edge module. The article will focus on two complimentary technics compliant with high volume manufacturing: