플래시 메모리 칩의 잔류응력 제거를 위한 IPL 어닐링

Abstract

Recently, ultra-thin chips with thicknesses of under 35 ㎛ have emerged as an option for thinner, high performance electronic devices. For reliable electronic devices and high throughput packaging processes, the mechanical properties of ultra-thin chips need to be accurately understood. Especially, the residual stress occurred due to shear force between the grinding wheel/ polish pad in wafer thinning process occurred in wafer thinning process could be affected the fracture strength of ultra-thin device. In this paper, the optimal condition to reduce the residual stress of the ultra-thin chip was found with respect to the various wafer thinning parameters. The residual stresses distributions along the thickness direction of the ultra-thin flash memory chip before/after IPL annealing were measured using Raman spectroscopy. To validate the IPL annealing, we perform the BOR test to measure the fracture strength of ultra-thin flash memory chip. From the study, the effect of the residual stress and the fracture strength of ultra-thin flash memory chip with respect to IPL annealing were discussed.