EDN’s Technical Editor, Paul Rako, has run a couple of articles touching on heatsink flatness and evaluating heat sinks. Here at ATS we applaud that public discussion as it is missing in heatsink selection.
The heatsink flatness article particularly caught our eye since Guy Dagan, of Cool Innovations, makes some excellent points on this topic. The key message though is that:
- Flat heatsinks attach surfaces are critical to getting the best thermal performance
- Flat semiconductors are an important part of the solution
At ATS we’ve experienced the same issues as they have at Cool Innovations. While we’ve approached the flatness issue for our maxiFLOW and other heatsinks differently than Guy has, the semiconductor lid flatness issue has vexed us.  At ATS we tend to favor phase change thermal interface material when we can use it as it does a nice job of filling in the gaps that Guy mentions in his article. But at one point our team got so concerned about lid flatness on semiconductors we actually invented our own IC package!
The package is known as maxiPACKAGE and it essentially provides a package that solves the semiconductor lid flatness issue while allowing for the attachment of heatsinks from ATS, Cool Innovations or anyone the OEM wishes.
Perhaps the best word picture of this issue comes from Tony Koryban and his Grill Cheese Theory (GCS) applied to thermal interface material; we’ve put together a quick three page info pack on this topic here: GCS_Theory