A Study On The Technology Of 2-D Measuring System With Nanometer Accuracy

In recent years,more and more attention is paid to the study of nanotechnology. Especially with the rapid development of mechanical,material and electronical industries,nanotechnology has covered a lot of ground. Among them nanometrology is an important branch of nanotechnology. At present ,measurement on nano level has been an important problem demanding prompt solution in the development of industry and science.On the base of detailed study and analysis of current nanotechnology and high accuracy laser displacement measurement technology,a new laser displacement measurement system with nanometric accuracy has been developed. Optical system with 8 times optical path difference is designed. The following materials and methods are utilized:simple,stable and compact optical layout；coupled defferential interferometry；symmetrical optical paths；multiplication optical path difference； Abbe principle.Large-scale super-micromotion constant controllable piezoelectric motor is proposed. The controlling syetem is optimized to make PZT motor movie more reasonable and steady.High accuracy interferometric signal processing system is proposed. A series of techniques such as DC adjustment,filtration,amplification are adopted. The influence on division precision of three errors (quadrature phase shift error,unequal amplitude of two signals and zero offsets) is analysed. Then the three errors are compensated by Heydemann model to achieve two quadrate signals. By division and counting the last result of the interferometric system is obtained.At last, the accuracy of the total measuring system is analyzed. The calculated accuracy of the total system is about ±2.5nm. On the base of accuracy analysis,the test was given by comparing with the capacitive micrometer and obtained the measuring accuracy of 10-12nm.