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Author(s): Kathleen A. Gilbert, Nicolas D. Huffman, Sara N. Paisner, Timothy D. Fornes

Keywords: c-mode scanning acoustic microscope, fillers, humidity testing, jesd22-a102-c accelerated moisture resistance test method, laser flash lfa 447 nanoflash apparatus, stencil printability, thermal adhesives, thermal conductivity, thermal diffusivity, thermal gels, thermal greases, thermal interface materials, tims, transient plane source technique, x-ray

Abstract: The development of higher power chips in the electronics industry has led to the requirement of high performance thermal interface materials (TIMs) due to the increased heat output by these chips. Desirable features of a high performance TIM include that the material be highly thermally conductive, and that it should have a relatively low viscosity. Companies can spend long periods of time trying to find the amount of filler content in a given TIM that will optimize the viscosity and thermal conductivity. This article presents a mathematical method of determining the filler content that will produce the most efficient packing of particles which results in a material of relatively low viscosity. The article shows that the method was capable of predicting the filler content that produces close to the minimum viscosity for  thermal greases, thermal gels, and thermal adhesives. These greases, gels, and adhesives were then tested for thermal conductivity.

Reference: 24th Annual IEEE Semiconductor Thermal Measurement and Management Symposium (2008) 90-94

DOI: 10.1109/STHERM.2008.4509372