Thermal Management of Electronic Equipment: A Review of Technology and Research Topics

Abstract

Increasing miniaturization of microcircuits on chips of increasing size and new schemes of electrical connection, such as flip-chip bonding and surface mounting, are setting more demanding criteria regarding the thermal field within electronic equipment. While the search for a solution to meet a set of prescribed design criteria is becoming more complex, the body of available data needed to perform such a search is quite small. This article describes the two primary functions to be implemented by electronic heat transfer research: the definition of thermal design criteria and the establishment of a thermal packaging database. Examples of actual designs of packages are drawn from recent publications to illustrate the points of technical importance. The examples are packages of DRAM chips, flat-leaded packages of logic chips, and modules with dismountable heat sinks. These examples are used to address thermal stress problems, the problems of fin design, and thermal interface management, respectively. In the section on natural convection cooling, the effects of various factors on the uncertainties pertaining to heat transfer coefficient are assessed in light of the correlations proposed in the current literature. The section on forced convection cooling deals with the problem of heat transfer from an array of packages in a parallel-plate channel. The final section is devoted to the research topics of nucleate boiling heat transfer enhancement, from the surface of a small component, and microchannel cooling.