Application of Fringe Reflection Method for Specular Surface Profile Measurement

Abstract

The main purpose of this study is to measure the specular profile using two different fringe reflection methods as well as exploring the differences between the two methods The two methods performed in this experiment include the vector method and the normal vector method They are used to measure the wafer and the male die as well as the female die respectively Finally the results of these experiments are then compared using the surface roughness meter and displacement sensor The root-mean-square error (henceforth RMSE) of the wafer with 30 μm of range of height is found to be within 1 69 μm The RMSE of the male die and female die with 18 mm of range of height is found to be within 0 22 mm In the experiment it is observed that the larger the pitch of fringe the more visible the wave profile of the specimen In order to avoid the slope of the specimen being too large which may ultimately cause the camera to not be able to clearly observe the image on the screen from the specimen The specimen must be properly tilted When integrating the x-direction of the slope of a female die the female die geometry relationship will cause integrations that occur only in horizontal directions to commit integral errors It should be priorly determined whether or not the geometry of the specimen will cause the slope in the central axis of the integral or the area near it to be absent If the slope is indeed absent the area where the slope exists should be integrated first followed by integrating the area where the slope does not exist It is also necessary to find the adjacent slope point in the direction of such integration then search for the integration result of the surrounding from the slope point Continue the integration until all the slope points have completed their respective integration

Date of Award	2019
Original language	English
Supervisor	Terry Yuan-Fang Chen (Supervisor)