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A Comparative Study of Heat Transfer Mechanisms from a VLSI Integrated Circuit Die with and without a Heat Spreader
V. Lakshminarayanan and N. Sriraam

Heat generation occurs in all electronic components. The combination of high operating speeds, shrinking die sizes, billions of transistors and other devices go into the construction of a very large scale integrated circuit such as a microprocessor.This leads to larger component density per unit area of the die, higher power density per unit area, and such factors have increased the tendency of the die temperature of the VLSI devices to be high. Higher temperature affects the reliability of all electronic components. Ways and means have to be found to efficiently dispose of the heat generated during operation into the ambient. This paper presents the basic assessment of the amount of heat generated and heat transferred from a silicon die using various methods, based on the fundamental principles of heat transfer mechanisms.The effect of attaching a copper heat spreader to the top of an IC die through a conductive epoxy adhesive on the heat transfer and resulting temperature is calculated.

Keywords: VLSI, die, copper plate, reliability, Fourier’s law, Newton’s law of cooling, Stefan – Boltzmann law, heat transfer, conduction, convection, radiation, thermally conductive epoxy, ceramic substrate.

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