Fraunhofer回折による超精密加工面粗さの測定評価に関する研究

概要

論文の詳細を見る
A new method based on the Fraunhofer diffraction theory which can estimate RMS roughness of super smooth random surface such as the polished or lapped surface is presented in this paper. The relations between the random surface roughness and the Fraunhofer diffraction pattern are analized theoretically and an equation which can estimate quantitatively the RMS roughness is derived. In order to verify the validity of this proposed method, computer simulations as well as experiments for the silicon wafer with a surface roughness of 1-10 nm R_< : rms> are carried out. In addition, STM is used for checking the surface roughnesses of the workpieces. Consequently, it is found that this method makes it possible to measure the surface roughness within a 10% error from 1 nm to maximum 120 nmR_< : rms>. Moreover, from experiments using an improved measuring system which can evaluate the texture all over the surface of a silicon wafer, this method is found to be useful for measuring quickly and easily the ultra fine surface roughness of the complete surface even if workpiece is set with a tilt and vibrates when the table is moving.
1990-02-05