Timothy Jensen and Ronald Lasky, Ph.D, PE.
Modern electronics require an extremely large number of circuits to perform their many impressive feats. For example, a modern smartphone can have several billion logic circuits in the main microprocessor. This circuit density creates a significant amount of heat that must be dissipated. If the heat is not adequately dissipated, the life expectancy and performance of the circuits are significantly reduced. A revolution in thermal interface materials (TIMs) and designs has been a result of this necessary heat transfer. This paper will discuss the progress in this important field.
Today, however, significant differentiation in application requirements has driven the need for the development of multiple types of TIM materials. As a result, a TIM classification system is useful for guiding selections of materials to meet specific application requirements. In addition, testing and evaluation of TIMs is critical to proper selection for a specific application. It is also important to recognize that thermal conductivity alone is not the sole criteria for the selection of a TIM. The following sections will discuss these classifications and applications.
Metal TIMs can enable high heat dissipation and have a long life cycle, as they are not subject to pump-out. Many metal TIMs are available to meet a wide variety of demanding applications. Advancements in metal patterning have improved the effectiveness of metal TIMs by improving their compressibility. In other applications, combining liquid and solid metal TIMs has enabled TIMs to be used on surfaces that were typically not solderable.
Initially Published in the SMTA Proceedings