3D Inspection on Wafer Solder Bumps Using Binary Grating Projection in Integrated Circuit Manufacturing

For the measurement of the 3D surface of micro-solderballs in IC (Integrated Circuit) manufacturing inspection, a binary grating project lenses of high MTF (Modulation Transfer Function) with tilted project plane is designed in this paper. Using a combination of lenses and a tilted optical layout both on object and image plane, the wave-front aberrations are reduced and the nonlinear image distortion is corrected with nonlinearity compensation, This optical lens allows us to project the structured light pattern to the inspected objects efficiently for clear deformed coded imaging, it could be used to online measure 3D shape of micro-solderballs with high precision and accuracy.