Using Ag Sinter Paste to Improve the Luminous Flux and Reliability of InGaN-Based LED Package for Commercial Vehicle Daytime Running Light

Abstract

We investigated the effect of different types of die attach adhesives on the performance and reliability of InGaN-based LED packages. At 260 °C, the average shear strength was 10.00 and 22.30 MPa for Ag epoxy and Ag sinter paste samples, respectively. LED packages with the Ag sinter paste produced lower thermal resistance than the Ag epoxy paste sample. The Ag epoxy and sinter paste samples gave the thermal resistance (from junction to PCB) of 9.82 and 9.27 K W−1, respectively. The chip temperature of the Ag epoxy and sinter paste samples was 122.1 °C and 121.5 °C, respectively. The Ag sinter paste contained smaller Ag flake and less resin than the Ag epoxy paste sample. The luminance flux at 700 mA of LED packages with the Ag sinter and epoxy pastes was 177.5 lm and 176.8 lm at 85 °C. Unlike the Ag sinter paste samples, 60% of the Ag epoxy paste samples were cracked at 300 °C. The luminous flux maintenance of the Ag epoxy and sinter paste samples was 97.36% and 99.54%, respectively. Unlike the Ag epoxy paste samples, the Ag sinter paste samples exhibited higher stability against delamination (cracking) and higher lumen maintenance than the Ag epoxy paste samples.