The Research Of Displacement Traceability And Linewidth Measurment Technology On Metrological UV Microscope

Currently,the measured value of UV microscope cannot directly traceable to international SI unit of length reference.For this reason,the National Institute of Metrology,China is developing a metrological 248 nm DUV microscope.In the dissertation,displacement traceability and linewidth measurement technology of this device are researched.The measurement for micro-nano linewidth of this device is accomplished.The measured value can be traced directly to the laser wavelength.Main research contents are as follows.Firstly,the measuring principle of this metrological 248 nm DUV microscope was discussed.Hardware Structure of this device was also introduced.Laser interferometer measurement system with no Abbe error and wavelength compensation module is designed,using laser heterodyne interferometry.Displacement measurement and traceability during the scanning process was achieved.Hardware circuit of interferometer system is designed to achieve measurement data high speed hardware output,data update rate can reach up to 20 MHz.Secondly,PMT selection and the design of light splitter structure was completed,according to the measurement requirements.High-performance hardware circuit is designed achieve the PMT output signal amplification and filtering.Filter circuit employed low-pass MFB architecture with RC added in series with the output,has a high filtering performance and stability.Meanwhile,in order to reduce electromagnetic interference,shielding box was designed.Furthermore,the system of signal acquisition and trigger is designed to completed equal-displacement interval data acquisition in the scanning process.Synchronous triggering accuracy of this system can be achieved 25 ns.System hardware is used PXI architecture,FPGA and high-speed AD acquisition card.Using FPGA High-speed hardware processing capability and synchronous bus provided by PXI,meet the hardware requirements of the system.System software is developed based on LabVIEW2014 and LabVIEW FPGA Module to realize equal-displacement interval trigger and data acquisition.This software also has Interferometer system data real-time display,scan history Recording,Linewidth scanning curve preview,data storage,data analysis and so on.Finally,micro-nano linewidth measurement experiments of this device were carried out.The measurement capability of this device was verified by 2um grid linewidth measurement experiment.The standard uncertainty of this device introduced by measurement repeatability is 2.97 nm.