Advanced Thermal Lid Attach Adhesive for High Performance Computing (HPC) Package

Heat sinks are used to (a) transfer the heat emitted by chips to the external environment through thermal interface materials and (b) protect chips from breaking during collisions. Because heat sinks serve crucial functions in flip chip ball grid array (FCBGA) packages, lid adhesives that bond heat sinks and substrates must be resistant to heat and chemical corrosion to ensure favorable adhesion even after being subject to manufacturing processes. This study compared a mass-produced adhesive with three novel adhesives developed by different manufacturers. To ensure material consistency, the aforementioned adhesives had silicone resin as their main component. The properties of the four adhesives, including their coefficients of thermal expansion (CTE), storage modulus, thermal conductivity, and pull force, were measured. The measured properties were then entered into simulation model to analyze and derive the stress in FCBGA packages, on the basis of which the performance of the materials was determined. Finally, assembly experiments were conducted to verify the feasibility of the novel adhesives in large-body FCBGA packages.