Application Note 653 17
Intel740™ Graphics Accelerator Thermal Design Considerations
NOTE: Approximately 70% of the ultimate adhesion bond strength is achieved with initial application, 80-90% of
the ultimate adhesion bond is achieved within 15 minutes and ultimate adhesion strength is achieved
within 36 hours.
4.2.3.4 Reliability
As every motherboard, system, heat sink and attach-process combination may introduce variance
in attach strength, it is generally recommended that the user carefully evaluate the reliability of the
completed assembly prior to use in high volume. Some Test recommendations can be shown in
Table 4.
NOTES:
1. The above tests should be performed on a sample size of at least 12 assemblies from 3 lots of material.
2. Additional Pass/Fail Criteria may be added at the discretion of the user.
4.3 Thermal Interface Management for Heat Sink Solutions
For solutions where a heat sink is preferred, to optimize the heat sink design for Intel740 graphics
accelerator, it is important to understand the impact of factors related to the interface between the
mold-cap and the heat sink base. Specifically, the bond line thickness, interface material area and
interface material thermal conductivity should be managed to realize the most effective heat-sink
solution.
Table 3. Tape Attach Application Temperature/Pressure Option
Pressure Temperature Time
10 psi (0.069 mPa) 22°C 15 seconds
30 psi (0.207 mPa) 22°C 5 seconds
10 psi (0.069 mPa) 50-65°C 5 seconds
30 psi (0.207 mPa) 50-65°C 3 seconds
Table 4. Reliability Validation
Test
1
Requirement Pass/Fail Criteria
2
Mechanical Shock
50G, board level
11 msec, 3 shocks/direction
Visual Check
Random Vibration
7.3 G, board level
45 minutes/axis, 50 to 2000 Hz
Visual Check
Temperature Life
85°C, 2000 hours total, checkpoints occur at 168, 500,
1000 and 2000 hours
Visual Check
Thermal Cycling
-5°C to +70°C
500 Cycles
Visual Check
Humidity
85% relative humidity
55°C, 1000 hours
Visual Check
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