At the same temperature, the thermal conductivity of adhesive with epoxy was higher. However, the common material of thermal conductive adhesive was silicone in the industry. There was very little introduction to the application of thermal conductivity adhesives for epoxy and silicone. The purpose of this study was to explore high-efficiency thermal adhesive solutions and meet the heat dissipation requirements of high-end electronic components.
Heat dissipation was one of the core problems in system in package (SiP). It directly determined the application environment of SiP. In this paper, the authors built a data processing of SiP and a temperature measuring point was set up inside the chip, which could observe the maximum working temperature. The heat of SiP transferred outward through the following components in turn: chip, heat sink, thermal conductive adhesive and metal plate. There were two materials of thermal conductivity adhesive: silicone and epoxy.
Adhesives did not play an obvious role in SiP, and this related to its thermal conductivity and thickness. Interestingly, the operating temperature of SiP had a linear relationship with the substrate temperature and current. Silicone-based thermal conductive adhesive demonstrated excellent heat dissipation performance. After replacing glue with solder paste, the working temperature of SiP dropped by 17°C, and the metal interconnection effectively improved the heat dissipation efficiency.
Although epoxy had a high thermal conductivity, the adhesive detached at high temperature. The simulation results showed that at an ambient temperature of 90°C, the SiP’s temperature of adhesive-free, epoxy and silicone were 121°C, 119°C and 117°C, respectively. The maximum error between actual temperature and simulation result was 4.2%.
