Thermal-Mechanical Considerations during Thermal Solution Assembly of Bare-Die Packages

The demands for thinner bare-die BGA packages for overall stack height reduction and electrical performance improvement has added complexity for thermal solution design, manufacturing and assembly processes associated with microelectronic packages in mobile computer systems. Typically, in the computer system manufacturing process, the thermal solution assembly is typically a manual process. The interaction with the bare-die package component stack during the assembly process is very critical, creating a need for an in-depth characterization to understand the impact of design and manufacturing on product quality and performance. Modeling and experimental methodologies are developed to understand and quantify the complex interactions of thin bare-die package with thermal solution and evaluate potential thermo-mechanical risks as well as potential mitigation options. Areas that are discussed in the paper include assessments of structural integrity at the component and board levels to identify potential fail modes, component thermal performance, impact of commonly used thermal solution options for cold plate designs, retention mechanisms and enabling load distribution and the influence of thermal solution assembly process. Recommendations for improved thermal enabling are also discussed.