Heat spreader attach: a microprocessor thermal solution

AMD's heat spreader attach process utilizes a thermally conductive silicone adhesive which can be quickly and easily dispensed and cured. The heat spreader attach assembly process eliminates the need for gross leak testing (a.k.a, bubble testing), an expensive and time consuming test and reduces the capital equipment required while increasing production capacity compared to the thermal grease assembly process. A novel feature of adding "corner supports" increases the mechanical and interfacial reliability by preventing the heat spreader from moving and thereby reducing the stresses on the die/adhesive and adhesive/heat spreader interfaces. The paper will discuss the heat spreader's thermal performance advantage over the thermal grease/lid combination. It will also discuss the DOEs to establish a robust assembly process. Fixture force and location were varied to determine the effect on bond line thickness and to determine the process window. Reliability data will be presented which shows that the heat spreader attach process is capable of withstanding all applicable reliability tests.