Determination of stress distribution in III-V single crystal layers for heterogeneous integration applications

Double crystal X-ray diffraction imaging and a variable temperature stage are employed to determine the stress distribution in heterogeneous wafer bonded layers though the superposition of images produced at different rocking curve angles. The stress distribution in InP layers transferred to a silicon substrate at room temperature exhibits an anticlastic deformation, with different regions of the wafer experiencing different signs of curvature. Measurements at elevated temperatures (≤125 C) reveals that differences in thermal expansion coefficients dominate the stress and that interfacial particulates introduce very high local stress gradients that increase with increased temperature. For thinned GaAs substrates (100 μm) bonded using patterned metal interlayers to a separate GaAs substrate at ∼200 C, residual stresses are produced at room temperature due to local stress points from metallization contacts and vias and the complex stress patterns can be observed using the diffraction imaging technique. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)