Computer Processing Unit Retention Module
Original Publication Date: 2002-Oct-11
Included in the Prior Art Database: 2003-Jun-21
Until recently, the interface between the heat sink base and the processor heat spreader cap has predominantly been thermal phase change material. When heated, a solid phase change material pad will flow thermally conductive liquid between the CPU and the heat sink base, increasing thermal conduction through the interface. When this liquid cools due to system power-down, re-solidification occurs, causing an air tight, epoxy-like, bond between the heat sink base and the processor heat spreader cap. This bond, and the tendencies of Intel to reduce the processor pull-out force, are the main reasons processors are unintentionally and undesirably pulled from their locked socket, causing potential damage it in the process. Currently, thermal greases, which are the thermal material of choice in servers due to improvements in thermal condictvity, have made slight improvements to this processor pull-out dilemma. The breakout force (processor from socket) of approximately 150 lbs. is exceeded due to suction created in the viscous interface between the processor and the heat sink. The socket retention alone is not enough to prevent this from happening. It is suspected that this industry wide problem can cost the manufacturer hundreds of thousands of dollars each year due to damaged processors. Desktops still utilize phase change materials. The "Computer Processing Unit Retention Module" abolishes processor pull-out by restrictiong upward movement of the processor from its respected socket. This better allows for easy removal of the heat sink for remanufacturabilty and customer rework, as well as elimination of the potential for processor damage. Furthermore, attention that has been devoted to improving heatsink-processor release properties can be directed toward improvements in thermal conductivities. The four images below show how the "Computer Processing Unit Retention Module" is tied to the heat sink retention module to ensure against processor pull-out.