C4 bumps provide the means of soldering microchips to the pin package. A grid of very small solder bumps deposited on the silicon face of the chip is aligned to the package, where the chip is fixed in place by them, and they electrical signal continuity and routing. Pitch, uniformity and dimensions of the C4 bumps are all critical to process control.
Monitor Bump Line applications using a HRP series profiler to ensure defect free soldering of all process steps and bump
uniformity across a wafer. Stylus profilometry, using products such as the tabletop stylus profiler P-16+, or the stylus profiler HRP-350 with its automated wafer handling, is the solution for measuring C4 bumps. Applications are available for all stages in the Bump Line process,
including Resist without Solder, Partial Solder Plating, Full Solder Plating, and Solder Plating
stripped Resist wafers.
Stylus profiling uses a very finely pointed and balanced tip, drawn across a surface to measure height variation with extreme precision. C4 bumps involve materials which are of varying hardness and density, making stylus profilometry the most suitable measurement technique.
