Development of conductive fusion technology : Advanced die attach materials for high power applications

High power semiconductor applications such as RF and microwave applications, GaN and SiC power devices and High Brightness LEDs (HBLED), require a die attach material with high thermal conductivity to efficiently release the heat generated from these devices. In these types of applications, the main path for heat dissipation is from the device through the die attach material. In order to provide an effective thermal path, it is important for the die attach material to maintain good interfacial contact with backside of the die and substrate. In addition to meeting the necessary thermal performance, die attach materials are required to offer high reliability, ready for high volume manufacturing (HVM), and be readily available while meeting RoHS compliance requirements. Current die attach solutions such as eutectic solders (e.g. AuSn and lead (Pb) solders) have been industry standards offering good reliability and effective thermal conductivity, however both have their drawbacks. High thermal conductive silver epoxies and sintered silver adhesives have provided an attractive alternative to solders, but may fall short in performance for high temperature or high stress applications. Recent developments in sintered silver die attach pastes offer the latest solutions to replacing solders in the semiconductor market, providing a RoHS compliant material with unmatched thermal performance and high reliability. This presentation will focus on development of a reinforced sintered silver die attach solution for high power semiconductor applications with focus on a pressure-less, low temperature sintering technology that offers high reliability for high temperature (250°C) applications.