Effective Approach to Achieve Zero Interfacial Delamination on High-Power Automotive Devices After Reliability Test

The demands of high-power devices for automotive applications are rising rapidly, especially with the booming sales of electric vehicles in recent years. Nevertheless, the interfacial delamination of devices under stringent reliability stresses is often an issue to the manufacturers. To address this issue, lead frame roughening technology is usually employed to improve the interfacial adhesions through mechanical interlocking mechanisms. While this method is generally applicable, it incurs sizeable equipment footprints during mass production with processes including pre-cleaning, roughening, and post-cleaning of the lead frames. Additionally, the usage of hazardous chemicals in the lead frame roughening technology may pose environmental and safety concerns. In this study, a simple yet economical adhesion promoter coating approach is proposed to improve the interfacial adhesion for high-power silicon carbide (SiC) automotive devices. Unlike the roughening technology which only focuses on lead frame surfaces, the adhesion promoter is coated on all molding surfaces including lead frame, wire, solder and die surfaces. This total molding surface coating inclusiveness is essential to eliminate the seed of delamination to grow from all possible interfaces. As a result, the coated automotive devices can achieve zero delamination after the stringent IPC/JEDEC moisture sensitivity level (MSL) 1 conditioning.