Wafer bonding defects inspection by IR microphotoelasticity in reflection mode

Abstract

It is demonstrated that high quality stress-induced birefringence maps in silicon with a high lateral resolution can be obtained by microphotoelasticity in reflection mode at wavelength of 1.31 μm. This technique was applied to inspection of Si-Si wafer bonding defects with variable magnifications. It is shown that defects with an apparent size as small as 20μm in diameter can be observed with a 2μm lateral resolution.