Study On Residual Stress Detection And Analysis Method Of Muller Matrix Ellipsometer

Various transparent amorphous and crystalline materials are widely used in precision optical detection systems and semiconductor integrated circuits due to their excellent optoelectronic and mechanical properties.Residual stress will affect the performance and yield of the device.In particular,as the degree of integration becomes higher,the size of the material becomes larger,the thickness becomes thinner,the phenomenon of stress concentration becomes more common,and the cost of material damage becomes higher and higher,the effect of small stress is more prominent.Therefore,the detection of small residual stress is of great significance for process optimization and reducing material damage costs.However,at present,the detection of small residual stresses lacks a means of sufficiently high resolution and sufficient measurement depth.The Muller matrix ellipsometer is an instrument sensitive to material properties.Aiming at the small residual stresses in the annealed and polished transparent samples,this paper studies the method of detecting and analyzing the residual stresses of the Muller matrix ellipsometer in transmission mode.Mainly carried out the following work:(1)The principle of measuring residual stress by the Muller matrix ellipsometer is researched,and the method and steps for measuring the residual stress of the Muller matrix ellipsometer are established.Based on the stress?optical law,the residual stress of the measured points is calculated from the phase difference at the center wavelength of the ellipsometric spectrum of the sample.(2)Discuss and establish the conditions that the sample to be measured and the sample stage must meet when measuring residual stress in the transmission mode of the Muller matrix ellipsometer,using 1/4 wave plate as the phase difference standard and air as the residual stress standard,the accuracy of measuring the phase difference and residual stress by the Muller matrix ellipsometer is preliminary verified.(3)The main factors affecting the residual stress measurement of the ellipsometer are explored,and the dual?frequency laser interferometer is used as a comparison method.The measurement results of the Muller matrix ellipsometer for measuring the quartz glass stress birefringence phase difference are compared and analyzed.The accuracy of the residual stress measurement of the Muller matrix ellipsometer is proved.(4)The residual stress distribution of the isotropic glass has been measured,and the accuracy of the ellipsometer to measure the residual stress of the anisotropic sapphire has been verified by the radial pressure method.The results show that the stress of the glass sample is distributed in a straight line symmetrical with the center of the circle,and the center is almost 0.Under the state of radial pressure,the phase difference at the center point of the sapphire increases linearly with the main stress difference at that point.The absolute value of the phase difference of each point in the diameter direction where the radial pressure is located increases with the principal stress difference,and changes in a quadratic curve;The absolute value of phase difference of each point in the diameter direction perpendicular to it decreases with the increase of the principal stress difference,and it also changes in the quadratic curve rule,which is consistent with the theory of radial compression.The residual stress distribution of polished sapphire in the test area is compressive and uniform.The experiment proves that the residual stress resolution of Muller matrix ellipsometer reaches 1.79 MPa / 0.1 °.