Intel Xeon processor LV Thermal Design Guide

Dual-Core Intel
®
Xeon
®
processor LV and ULV
August 2006 Thermal Design Guide
311374-002 29
Reference Thermal Solutions
6.5 Thermal Interface Material (TIM)
The thermal interface material provides improved conductivity between the die and
heatsink. It is important to understand and consider the impact of the interface
between the die and heatsink base to the overall thermal solution. Specifically, the
bond line thickness, interface material area, and interface material thermal conductivity
must be selected to optimize the thermal solution.
It is important to minimize the thickness of the thermal interface material (TIM),
commonly referred to as the bond line thickness. A large gap between the heatsink
base and the die yields a greater thermal resistance. The thickness of the gap is
determined by the flatness of both the heatsink base and the die, plus the thickness of
the thermal interface material, and the clamping force applied by the heatsink
attachment method. To ensure proper and consistent thermal performance, the TIM
and application process must be properly designed.
The processor reference thermal solution uses Honeywell* PCM45F. Alternative
materials can be used at your discretion. Regardless, the entire heatsink assembly,
including the heatsink, and TIM (including attach method), must be validated together
for specific applications.
Figure 17. 1U Reference Heatsink Thermal Performance versus Volumetric Airflow Rate