Compatibility Analysis of Liquid Gallium and Common Packaging Metals for Application in Electronic Component Thermal Management

摘要

Low melting point metals (LMPMs) offer a novel solution to the transient cooling needs of high-power density heat sources due to their high thermal and electrical conductivity. Gallium and its alloys are attractive for applications in high power pulsed energy systems due to a high figure of merit compared to other LMPMs as well as a transition temperature near ambient. However, considerations need to be made for gallium compatibility with common electronics packaging metals to avoid compromising thermal and phase change properties. The experimental presented evaluates gold, copper, nickel, platinum, and aluminum compatibility with liquid gallium. The study addresses concern that metals in packaging will migrate into the gallium, effecting its thermal properties.To evaluate the effects of any interdiffusion or intermetallic formation a Differential Scanning Calorimeter (DSC) was used to develop heating and cooling curves for gallium packaged with each of the materials. These test packages consist of DSC crucibles with metal thin-films deposited in material stacks typical of electronic microfabrication and packaging. Gallium is introduced to each crucible and ramped through the heating curve three times. Experimental results evaluate the thermal effects of any compatibility concerns with the selected materials. Samples are further analyzed with X-Ray Photoelectron Spectroscopy (XPS) to determine nickel and platinum suitability as a diffusion barrier and gallium penetration of the thin film stacks. These results will be used to further the investigation of direct-application of LMPMs to electronics for thermal management.