Intel Pentium 4 Processor with 512-KB L2 Cache on 0.13 Micron Process Thermal Design Guidelines

Thermal Specifications

24 Intel

Pentium

4 Processor Thermal Design Guide

3.3.3.2 Heatsink Preparation – Rectangular (Cartesian) Geometry

To measure the case temperature, a heatsink must be mounted on the processor or TTV to

dissipate the heat to the environment. The heatsink base must be grooved to allow a thermocouple

to be routed from the center of the heatsink without altering the IHS for heatsink attachment. The

groove in the heatsink has two features. The first is a 4.5 mm (0.180 inch) diameter relief for the

thermocouple bead and surrounding epoxy. The second feature is a 1.0 mm (0.040 inch) wide

groove that allows the thermocouple wire to be routed to the edge of the IHS/heatsink assembly.

The relief and wire routing groove should be shallow enough to avoid significant impact on

heatsink performance, while minimizing interference between thermocouple and the heatsink base.

Groove depth should be 0.6 to 1.0 mm maximum (0.025 to 0.040 inches). Notice the center of the

thermocouple bead relief is located 1.3 mm (0.050 inches) from the centerline of the heatsink. An

example of a grooved heatsink base is shown in Figure 8. It must be noted that the center of the

circle area needs to be located 1.3 mm (0.05 inches) off center from the location corresponding to

the thermocouple bead at the center of the IHS. This offset accommodates the bead of epoxy that

covers both the thermocouple and thermocouple wires.

Figure 8. Grooved Heatsink Bottom