Comprehensive study to enable successful probing of GaN wafer technology

Abstract

The power MOSFET wafers which base on silicon substrates are almost reaching end of road, lacking on both performance and cost. It was widely predicted in the industry that next generation wafers should come from Gallium Nitride (GaN) substrate. This new material is expected to be the dominant technology due to its competitive in almost all aspects. Many high power device providers are making deep dive efforts, hopefully to penetrate market earlier than all other competitors. The challenges in achieving that target include facing some of the strangest issues. One of the issues faced in GaN HEMT wafer is not able to perform proper testing as it is a normally-on device. A lot of efforts were invested into developing breakthrough probing process in order to determine quality of device before going into assembly packaging. In the process to develop robust probing methodology, there were many quality occurrences and concerns. Multiple rounds of evaluations were executed and finally obtained few robust options. Upon actual verifications, a new improved probing methodology was selected. It could provide reasonable and reliable measuring performance while concluding new circuits should be redesigned at wafer level. With this new probing method, time to market could reach extremely good performance, enabling competitive advantage in market penetration.