Heat Transfer in Electronic Packages

摘要: It was thought that the invention of transistor, with its relatively low power requirements, would greatly minimize, if not totally eliminate, all cooling concerns. Such thoughts, however, were short lived, as engineers sought to improve performance, cost, and reliability by packaging greater numbers circuits in an ever-smaller space. In fact, densities at component level have increased dramatically over years. mainframe computers, chips may be found dissipations ranging between 20 40 W, dissipation excess 10 W many PC workstation applications. Considering one example from a computer, 7 × 7-mm chip dissipating 30 results heat flux more than 6 105 W/m2. As shown Figure 4-1, this is only about two orders magnitude less on surface sun [1]. But sun’s temperature 6000°C, compared maximum operating range 100°C for typical semiconductor chip.