This thin bondline material accepts a higher contact resistance and slightly thicker bondline.
Gap Filling Pads
Thick bondline materials are designed to conduct the heat over a longer distance while still offering thermal resistance and withstand a significant degree of deflection. By being soft and compliant, gap-filling thermal pads deflect, flow and conform to surfaces very well. Pads come in a vast variety of material types with different conductivities, pressure/deflection responses, harnesses, tackinesses, electrical insulations, thicknesses, etc.
This type of filler comes in a two-part cure-in-place filler and a one-part non-curing filler (known as gels). The two-part cure-in-place filler is dispensed in a liquid state but subsequently freezes upon curing to a precise fit. The one-part thermal gel fillers do not cure after dispensing but remain in a viscous state indefinitely.
Both are entirely viscous during assembly and can be deflected to their minimum thickness. This makes it possible to optimize the design for a much thinner bondline than with pads, even when tolerance spans are large.
This material is a carrier membrane coated with a thermally conductive rubber compound. They are applied under direct pressure between the heat sink and heat source just like the thin bond like materials but are thicker and do not wet surfaces. They do flow slightly under pressure.
Effective heat transfer is vital to creating efficient and reliable products. Although great gains are being made in reducing the amount of heat that is produced, there is still a need to transfer heat in order to increase longevity. By choosing the correct Thermal Interface Material (TIM), reliability increases while failures decrease.