| With the development of ultra-precision processing technology,high-precision measurement of micro-nano structures has become a research hotspot.Among them,optical microscopic interferometric technology is widely used in the measurement of three-dimensional topography because of its high-precision,non-destructive,fast and other advantages.Different interferometric measurement methods are suitable for different test samples.For example,phase-shifting interferometry is often used for smooth continuous surface measurement,and wavelength scanning interferometry and white light interferometry are more often used for structural surface measurement.In interferometric measurement,external vibration interference will seriously reduce the measurement accuracy and even cause measurement errors.In response to the above needs,this thesis designed and built a Linnik-type multi-mode anti-vibration interferometric system,analyzed the influence of single-frequency vibration on the interferometric measurement,conducted experimental tests on the anti-vibration system,and evaluated the performance indicators of the system.The main work of this thesis is as follows:1.Designed and built a Linnik-type multi-mode anti-vibration interferometric system,compatible with multiple measurement modes such as wavelength modulation interferometry including wavelength scanning interferometry and wavelength tuning interferometry,white light interferometry,etc,could achieve nanometer-level precision measurement in a vibrating environment.2.A method for coarse acquisition of the measurement position was proposed,which could obtain the optical path difference of the current measurement position in real time.The feasibility of the method was verified by simulation,and the comparison experiment with wavelength scanning interferometry absolute distance measurement showed that the method could achieve sub-micron measurement accuracy.3.Active vibration suppression technology based on wavelength modulation interferometry was studied.The simulation and experiment verified the principles of wavelength modulation interferometry and active vibration suppression algorithms;discussed the influence of single-frequency vibration on wavelength modulation interferometry;designed single-frequency vibration suppression experiments with different amplitudes and frequencies,and conducted the system noise level tests.The results showed that the measurement accuracy of the system could reach the nanometer level,and the system noise of the anti-vibration system was better than the result of the system noise placed on the active vibration isolation table.4.Passive vibration suppression technology based on white light interferometry was studied.The simulation verified the principles of white light interferometry and passive vibration suppression algorithms;discussed the influence of single-frequency vibration and the experimental parameters such as scanning rate on white light interferometry;designed single-frequency vibration suppression experiments,and the results showed that the system could achieve nanometer-level measurement accuracy in a vibration environment. |
