Gels evolve to meet heat dissipation challenges

18th November 2014

Mick Elliott

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As high performance electronics spreads across a wide range of applications, it has stimulated a growing need to provide new innovative thermal materials that can effectively manage the heat dissipation challenges. To meet this need Parker Chomerics is constantly evolving its range of THERM-A-GAP thermally conductive dispensing gels in order that customers can maintain both system performance and reliability.

The company has recently extended its range of gels to offer thermal conductivity up to 6 W/m-k and typical applications include high performance devices requiring minimal thermal resistance, ranging from automotive electronic control units (ECUs), power supplies and semiconductors, through to memory/power modules, microprocessors/graphics processors, flat panel displays and consumer electronics.

Heat generated by high performance devices must be removed to the ambient environment to maintain the junction temperature of components within safe operating limits. Often this heat removal process involves conduction from a package surface to a heat spreader that can more efficiently transfer the heat away. The spreader has to be joined carefully to the package to minimise the thermal resistance of this newly formed thermal joint.

Typical thermal interface materials include THERM-A-GAP gels, which are supplied as pre-cured, single component compounds that can be dispensed over the heat generating package or component. These materials are silicone-based formulations loaded with conductive fillers, which are cross-linked to form a low modulus gel.

The latest additions to the THERM-A-GAP family need only ultra-low compression force to conform over irregular interfaces and can be applied to single devices with minimum bond-line thickness as well as to multiple devices with variable Z-axis tolerances. The gel structure provides superior long-term thermal stability and reliable performance over conventional greases, which suffer from pump-out and dry-out issues.

Offering low thermal impedance and high bulk thermal conductivity, further advantages of the new gels include the elimination of a cure cycle and the ability to be readily reworked, thus offering a highly attractive performance-to-price ratio. They require no refrigeration, no mixing and have no ﬁller settling issues. THERM-A-GAP also eliminates time consuming hand assembly, and reduces installation costs and customer manufacturing and purchasing (logistical) complexity.