Analysis of laser measurement for thin-film stress

Various measurements of thin-film stress are summarized. The basic theory and measuring principle of laser macro deformation analysis (including laser interference measurement and laser beam deflexion measurement) that utilized substrate curvature measurement are analyzed; the precision of different measurements is evaluated. The precision of laser interference measurement nearly reaches 0.92% and the least stress that could be measured is 15.7MPa. Compared to laser interference measurement,the precision of laser beam deflexion measurement is low,it is about 2.12%,the least stress which could be measured is 25.5MPa,and space resolution is low as well,which is approximate 100μm.