Fast Nondestructive Technique for Analyzing Deflection of Membranes Located on the Substrate

Abstract

We describe a nondestructive technique for automated analysis of deflection of substrate-mounted membrane structures, which are a key element of devices based on microelectromechanical systems (MEMS devices). The technique includes analysis of substrates with an optical profiler operating in a specialized mode and mathematical processing of measurement results. The technique allows determining the magnitude and sign of deflection of membrane structures for each measurement area. The procedure results in grading the value of deflection and detecting the following types of the state of membrane structures, which are important for assessing the yield and reliability of MEMS devices based on these structures: separation or rupture of the structure, its significant deflection, its slight deflection, and lack of a deflection. All results are displayed in map format on the surface of a substrate with membrane structures with the ability to access more detailed data. The developed technique makes it possible to localize regions with a maximum, predetermined, and low yield of suitable crystals of MEMS devices, as well as flawed regions over the entire substrate surface. The use of the technique significantly increases the accuracy and reduces the measurement time for estimating the yield of suitable membrane structures, and also makes it possible to adjust the process route so as to increase the yield of suitable crystals of MEMS devices.