“Magic” Material Tames Thermal Problems

Thermal management in electronic circuits can be challenging, especially when taking into account the many different materials in those circuits—each with its own temperature coefficients. But a new silicone elastomer developed by materials wizard NuSil Technology LLC, EPM1-2493, can be used to adhere materials with different coefficients of thermal expansion (CTE) as a stress remover. EPM1-2493 features a nominal thermal conductivity of 1 W/m/K and can be formed into bond lines as thin as 5 {LC MU}m. It does not have the typical paste-like consistency of most thermally conductive silicones; rather, it is a pourable, conformable liquid that is ideal for potting and filling recessed areas and spaces between package parts. It can even be used to prevent contamination of electronic components exposed to high heat, such as during solder-reflow processes or in hostile operating environments. The elastomer adheres well to aluminum; its adhesive strength can be improved with a primer, achieving average lap shear values to 120 psi (0.8 MPa).

According to Michelle Velderrain, Senior Technologist at Nusil, “The conformal quality of EPM1-2493 enables it to work well with complex geometries and where thin bond lines are required for lower thermal resistance. It can be used as an adhesive or coating in virtually any application requiring a thermally conductive, electrically insulative, self-leveling material.” The elastomer is ideal for attaching packaged devices, integrated circuits (ICs), and heat sinks to improve the thermal path. It is supplied in a 1:1 mix ratio and can be loaded into syringes for ease of application.