Intel 5000 Extruded Heatsink Profiles, Mechanical Interface Material, Thermal Interface Material

Reference Thermal Solution

6.5.2Extruded Heatsink Profiles

The reference thermal solution uses an extruded heatsink for cooling the chipset MCH. Figure 6-6shows the heatsink profile. Appendix A, “Thermal Solution Component Suppliers” lists a supplier for this extruded heatsink. Other heatsinks with similar dimensions and increased thermal performance may be available. Full mechanical drawing of this heatsink is provided in Appendix B, “Mechanical Drawings.”

6.5.3Mechanical Interface Material

There is no mechanical interface material associated with this reference solution.

6.5.4Thermal Interface Material

A thermal interface material (TIM) provides improved conductivity between the IHS and heat sink. The reference thermal solution uses Honeywell PCM45 F, 0.25 mm (0.010 in.) thick, 25 mm x 25 mm (0.984 in. x 0.984 in.) square.

Note: Unflowed or “dry” Honeywell PCM45 F has a material thickness of 0.010 inch. The flowed or “wet” Honeywell PCM45 F has a material thickness of ~0.003 inch after it reaches its phase change temperature.

6.5.4.1Effect of Pressure on TIM Performance

As mechanical pressure increases on the TIM, the thermal resistance of the TIM decreases. This phenomenon is due to the decrease of the bond line thickness (BLT). BLT is the final settled thickness of the thermal interface material after installation of heatsink. The effect of pressure on the thermal resistance of the Honeywell PCM45 F TIM is shown in Table 6-1.

Intel provides both End of Line and End of Life TIM thermal resistance values of Honeywell PCM45F. End of Line and End of Life TIM thermal resistance values are obtained through measurement on a Test Vehicle similar to Intel 5000 Series chipset’s physical attributes using an extruded aluminum heatsink. The End of Line value represents the TIM performance post heatsink assembly while the End of Life value is the predicted TIM performance when the product and TIM reaches the end of its life. The heatsink clip provides enough pressure for the TIM to achieve End of Line thermal resistance of 0.345°C inch2/W and End of Life thermal resistance of 0.459°C inch2/W.

Table 6-1. Honeywell PCM45 F TIM Performance as a Function of Attach Pressure

	Thermal Resistance (°C × in2)/W
Pressure on IHS(psi)
	End of Line	End of Life
2.18	0.391	0.551
4.35	0.345	0.459

6.5.5Heatsink Clip

The reference solution uses a wire clip with hooked ends. The hooks attach to wire anchors to fasten the clip to the board. See Appendix B, “Mechanical Drawings” for a mechanical drawing of the clip.

Intel® 631xESB/632xESB I/O Controller Hub Thermal Mechanical Design Guide 31