Numerical/experimental Hybrid Approach to Predict Substrate Warpag

A hybrid approach is proposed to enhance warpage predictability of thin advanced substrates. Experimental warpage data of thin advanced substrates is first obtained under various conditions. High sensitivity measurements (a contour interval of 6.25 microns/fringe or equivalent to shadow moire with a grating of 160 lines/mm) without painting the surface becomes possible through the advanced shadow moire method called Shadow Moire with Non-zero Talbot distance (SM-NT) in conjunction with the optical/digital fringe multiplication (O/DFM) method. The measured warpage is combined with an FEA approach called trace mapping to incorporate the effect of the copper trace layouts into the analysis. A hybrid model is created through calibration of the properties most critical to warpage, and the warpage values of the substrates at reflow temperatures are predicted.