Delamination Improvement for High Voltage Power Devices

Rapid growth in power and automotive application have led to higher quality requirements in semiconductor devices, and specifically for Automotive, passing AEC-Q101 life test is expected. It is well known that improved delamination will lead to a robust product, especially on high voltage and high moisture sensitive products. When these products are in a high humidity environment with bias voltage applied, such as Highly Accelerated Stress Test (HAST) / High Temperature Reverse Bias (HTRB) environment, delaminated devices will allow moisture and contamination to penetrate through the separation between mold compound and copper surface at the package entry point and propagate to the die top, allowing the ingress of contamination to die, causing accelerated leakage on life test. Therefore, good adhesion is required to prevent contamination either from external or internal sources. The target for this paper is to develop a solution for good adhesion between mold compound with copper surface and die top layer after time zero and pre-conditioning which is crucial for high voltage products. With the combined factor from lead frame design, surface roughening and improved adhesive mold compound, a package free from delamination at all interfaces at zero hours and preconditioning has been demonstrated. With its superb delamination performance, the high voltage MOSFET’s have had success in passing all the stringent moisture life tests especially (HAST and HTRB).