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

Thermal Specifications

22 Intel

Pentium

4 Processor Thermal Design Guide

3.3.3.1 Thermocouple Attachment

Thermocouples are often used to measure T

. Before any temperature measurements are made, the

thermocouples must be calibrated. This section describes the procedure for attaching a

thermocouple to the IHS for the case temperature (T

) measurement.

1. Obtain the necessary items needed for the quantity of thermocouple attaches desired:

• Fine point tweezers

• Exacto* knife (#11 blade)

• Thermocouples (Type K, 36 gauge, 36 inch, Teflon* insulation). Ensure that the

thermocouple has been properly calibrated

• 3M* Kapton* tape (or equivalent) cut into strips (1/8 inch X ½ inch)

• Epoxy (Omegabond* 101 or equivalent)

• Curing oven or equivalent.

2. Use a scribe to mark at the center of the package (IHS side) where the bead of the

thermocouple will be placed. Determine the center of the package by drawing two diagonal

lines across the length of the package. The intersection of the two lines is the package center.

(See Figure 5).

Figure 5. Desired Thermocouple Location

3. After the marks are scribed, clean the desired thermocouple attach location with a mild

solvent and a lint-free wipe or cloth. Alcohol or acetone should suffice. Cleanliness of the part

is critical for a strong epoxy bond after curing.

4. With thermocouple (T/C) in hand, locate the junction and straighten the wire by hand so that

the first 4–6 inches are reasonably straight. Use the fine point tweezers to ensure that the bead

and the two protruding wires are straight and untwisted. Ensure the second layer of

thermocouple insulation, sometimes clear, is not covering the bead.

5. Place a slight downward bend (~30°) in the protruding wires approximately 1/16 inch from

junction using the tweezers. This aids the user in ensuring the thermocouple junction contacts

the heat spreader surface.

6. Place the thermocouple on the surface of the part so the bead is contacting the IHS at the

desired location. Hold the T/C with one hand and use a pair of tweezers to apply a cut piece

of Kapton*

tape across the wire approximately about ¼ inch back from the bead. Apply

pressure to the tape to ensure a good bond. Apply additional Kapton tape along the length of

the wire to ensure a good temporary bond to the part. (See following Figure 6). Check for

electrical continuity between the thermocouple and the IHS using a multimeter. If there

is no electrical continuity between the thermocouple and the IHS, remove the thermocouple

and repeat Steps 4–6.