Surface Profile Measurement Of Large Visual Field Based On Infrared Scanning Interference

With the development of semiconductor industry and the growing maturity of ultra-precision machining technology,semiconductor devices are becoming increasingly diverse.Silicon wafers are widely used among them.As one of the important parameters of its quality,surface profile is required to be detected increasingly strict.In this paper,we proposed an infrared wide field surface profile measuring method for the detection of silicon wafers and their related semiconductor devices,which is based on scanning interferometry.It can quickly obtain a wide range surface profile characteristics of the measured object in a single measurement,and provide more effective and accurate means for industrial production detection.The main research contents of this paper are as follows:(1)Compared the characteristics of different three-dimensional profile reconstruction algorithms,and chose the appropriate algorithms for different targets.Meanwhile,applied the super-resolution reconstruction algorithm to the three-dimensional reconstruction,so as to solve the decrease problem of the lateral resolution,which is caused by the enlargement of the field,and improve the lateral accuracy of measurement.(2)Based on the principle of Michelson scanning interference,an infrared wide field surface profile measurement system is designed and built.Select the gauge block as the measuring target,to calibrate the pixel size of the infrared camera in the measuring system.The final measurement field is a circular area with a diameter of 2 inches,and the size of the three-dimensional reconstruction area is 28.3mm×28.3mm.(3)Completed the measurement and surface reconstruction of different targets: The first was to choose the plane mirror as the measurement object,the result was compared with the standard parameters.And the single-point repeatability deviation of the system is less than 30 nm.The second was to measure silicon wafers with different thicknesses,and got the relationship between deformation of silicon wafer and its thickness,also analyzed the influence of clamping devices on the measurement results.Finally was to measure the silicon substrates,which is used in the biomedical field,and its surface and internal structure were reconstructed.