The IHS spreads heat from the chip to a wider area and minimizes on-chip temperature gradient caused by asymmetric power distribution. The package features an integrated heat spreader (IHS) that is attached adhesively to the chip with a first-level thermal interface material (TIM-1) the TIM-1 couples the chip and IHS thermally and mechanically. ДЄ typical structure of the high performance processor package is shown schematically in Figure 1, illustrated with a picture of CPU processor package of the Fujitsu high-end server PRIMEPOWER2500. Cooling capability at the package level is becoming critical for the processor architecture and design, and is considered a major focus of research and development efforts by the server manufacturers. Local ambient temperature is increased due to high-density packaging, and decreased junction temperature is desired to ensure high reliability and suppress leakage current in the processor. In addition, shrinking temperature budget is bringing about challenges to thermal management of the high-performance processor package. These hot spots result in locally elevated temperatures and large temperature gradients across the chip, adversely impacting the processor performance and reliability, as well as reducing the cooling efficiency. Furthermore, advancements in miniaturization and design complexity are also causing highly asymmetric power distribution in the processor, so that in some local areas, the power density is much higher than that of the on-chip average, producing what is called a hot spot. Power dissipation of high performance microprocessors (CPUs) is increasing continuously. Along with high-speed and large-scale transmission performance, the servers are required to have high reliability, high efficiency, and environmental compatibility features, such as low-power consumption, compactness, low noise, etc. High-performance computer servers are widely used in leading-edge research, development, and service fields, where significant data processing and computing capabilities are required.

Procssor heat level