Filter
Top Products
Thermal Metrology
Thermal and Mechanical Design Guidelines 15
3 Thermal Metrology
The system designer must measure temperatures to accurately determine the thermal
performance of the system. Intel has established guidelines for proper techniques of
measuring (G)MCH component case temperatures.
3.1 Case Temperature Measurements
To ensure functionality and reliability, the (G)MCH is specified for proper operation
when T
C
is maintained at or below the maximum temperature listed in Table 2. The
surface temperature at the geometric center of the die corresponds to T
C
. Measuring
T
C
requires special care to ensure an accurate temperature reading.
Temperature differences between the temperature of a surface and the surrounding
local ambient air can introduce error in the measurements. The measurement errors
could be due to a poor thermal contact between the thermocouple junction and the
surface of the package, heat loss by radiation and/or convection, conduction through
thermocouple leads, or contact between the thermocouple cement and the heatsink
base (if a heatsink is used). To minimize these measurement errors a thermocouple
attach with a zero-degree methodology is recommended.
3.1.1 Thermocouple Attach Methodology
1. Mill a 3.3 mm [0.13 in] diameter hole centered on bottom of the heatsink base.
The milled hole should be approximately 1.5 mm [0.06 in] deep.
2. Mill a 1.3 mm [0.05 in] wide slot, 0.5 mm [0.02 in] deep, from the centered hole
to one edge of the heatsink. The slot should be in the direction parallel to the
heatsink fins (see
Figure 3).
3. Attach thermal interface material (TIM) to the bottom of the heatsink base.
4. Cut out portions of the TIM to make room for the thermocouple wire and bead.
The cutouts should match the slot and hole milled into the heatsink base.
5. Attach a 36 gauge or smaller calibrated K-type thermocouple bead or junction to
the center of the top surface of the die using a high thermal conductivity cement.
During this step, make sure no contact is present between the thermocouple
cement and the heatsink base because any contact will affect the thermocouple
reading. It is critical that the thermocouple bead makes contact with the
die (see
Figure 2).
6. Attach heatsink assembly to the (G)MCH and route thermocouple wires out
through the milled slot.