233 Thermal Deformation Analysis of Micro IC Composite Structures
Details
Moire interferometry technique was adopted to analyze the thermal deformations of four kinds of flip-chip devices mounted on FR-4 substrate and multi-layer substrate, with and without underfill. A thermal loading was applied by heating the devices from room temperature to an elevated temperature. The experimental results showed that the underfill gave similar curvatures of silicon chip and the substrate. In the flip-chip devices mounted on the multi-layer substrate, thermal expansion coefficient mismatch between the chip and substrate was reduced, and bending deformations were decreased. The deformation of solder balls in the underfilled flip-chip device mounted on the multi-layer substrate was the least in the four kinds of flip-chip devices. The thermal deformations of Stacked-MCP (Multi Chip Package) were also measured by phase-shifting moire interferometry. Digital image processing was introduced to determine the deformations with a sensitivity of nanometer scale.
