Gap fillers are thermal interface materials (TIMs) that move heat away from sensitive components in electronic assemblies. They’re usually made of silicone rubber and contain a ceramic filler. Like other types of TIMs, gap fillers are designed to fill the tiny air gaps between a heat source and a heat sink. Most gap fillers are inherently tacky and have a doughy consistency, but engineers can also choose materials with a non-tack surface for manual assembly.
Gap fillers provide greater stability than phase change materials (PCMs) that melt or solidify at certain temperatures. They’re also easier to install than thermal greases or pastes. For fast, precise, cost-effective fabrication, gap pads are die cut from sheet materials into specially-shaped parts called pads. These die cut products are available with release liners and pressure-sensitive adhesives (PSAs). For heat management in electronic assemblies, gap fillers with specific features may be required.