The Application of Two-Dimensional X-ray Hot Stage in Flip Chip Package Failure Analysis

Advancement of silicon and packaging technologies toward lower power and higher functionality requires better understanding between materials and process interactions. This paper illustrates the applications of 2-D X-ray metrology incorporated with a hot stage system for the first time in the literature, which allows one to simulate heating profiles of up to 300^°C and observe the behavior of materials in situ within the packages. Three case studies are discussed: 1) segregation of metal particles in the next-generation thermal interface material, leading to corner thermal resistance (Rjc) degradation; (2) first level interconnect (FLI) solder bump bridging during chip attach of a large die server package with high substrate die area warpage in which limits of the die area substrate warpage need to be set in order to avoid FLI solder bump bridging during the chip attach solder reflow process; and 3) second level interconnect solder joint bridging at the surface mounting process of a large die package attached with an integrated heat spreader. By being able to study failures in situ at high temperatures, a new dimension to the package failure analysis is presented in this paper.