In scanned probe measurements of micrometer- or nanometer-scale lines, it is nearly impossible to maintain the sample in a perfectly level position, and even a small amount of tilt angle can contribute to the accuracy of the result of measurand such as linewidth or step height. The current practice in image processing to deal with this matter is to conduct a line-by-line analysis to find the best fit of the substrate profile and subtraction of this background from all data points, thus describing a 3-D plane turns as a series of lines and processing them in succession in the x and y-directions.In this paper a coordinate transformation method is proposed. The new coordinate system depends on the inclined angle of the sample. The method can mathematically derive, and hence correct all tilts around the x-, y-, and z-axes and produce a leveled image simultaneously. Feature dimensions such as width, height, sidewall angle and pitch were calculated based on simulated images using the coordinate transformation method and other methods. The result shows the advantage of the proposed method.
Citation: Scanning, The Journal of Scanning Microscopies
Pub Type: Journals
coordinate transofmation, image, line, measurement, nanometrology, scanning probe, semiconductor, step, surface metrology