During the initial bring-up and debug stages of the design, removal of the heatsink is not an uncommon practice. Care should be taken so that device damage does not occur and that the device and heatsink are properly cleansed to allow proper reassembly without compromising the thermal integrity of the system. The thermal attachment should be disassembled so as to not create excessive uneven pressure to the device. This should only be used early in the prototyping and assembly stages, but not during operation. Often this is opposite to the steps that should be taken during assembly. The TIM often forms a bond that remains after the attachment is removed that can cause device damage if the heatsink is directly lifted. It is suggested to remove the thermal solution with a twisting motion as a means to break this bond. Sometimes it becomes necessary to heat the heatsink to further soften the TIM material so that excessive extracting force is not exerted on the device.
The TIM material should be cleaned from the device and heatsink and new TIM applied prior to reapplying the thermal solution. Follow the guidelines provided by the TIM provider for proper methods of TIM removal. Some consideration to the solvents used during the cleaning process should be taken to ensure corrosion or damage does not occur to the device or thermal solution. Some solvents that Xilinx has had success with include:
- Best – Toluene
- Better – Acetone
- Better – Isoparaffinic hydrocarbon (Isopar and Soltrol)
- Okay – Isopropyl alcohol