SiC semiconductor power devices have become the subject of great interest in recent years as the most promising technology to substitute the Silicon (Si) based devices used presently in high power and high temperature microelectronic applications. The benefits to SiC include high temperature capability, faster switching speeds and improved efficiency (due to lower specific on-resistance and lower switching energy as a wide band-gap device). Due to high costs of SiC, the size of the chips are typically much smaller compared to Si devices of the same voltage level.
Subsequently, the SiC chips have higher power density and require better heat dissipation and cooling design to better handle higher local current densities. With these requirements the demand for better test and inspection methods is also challenged. One proven test method used for inspecting these types of packages is Acoustic Micro Imaging (AMI). AMI is a nondestructive inspection technique that utilizes high frequency ultrasound to detect a wide variety of defects or “air-gap” type flaws such as cracks, voids, dis-bonds and/or de-laminations within materials.
In applications when heat transfer is critical, the ability to detect “air-gap” type flaws can be crucial since an air gap often means less bond and/or surface area for heat dissipation and thus further cause for potential failure. This presentation will review the basic concept of semiconductor power device package design and the requirement for inspecting those type packages for dis-bonds and/or de-laminations using AMI.