Measurement of texture using backscattered electrons

The design and development of a device to quantitatively measure surface texture using backscattered electrons (BSE) is described. Both theoretical and engineering considerations are discussed. Four BSE detectors,located at the corners of a square,centered on the illuminating beam, are used. The detector geometry and the location of the point of interrogation on the specimen surface are used in determining the partial derivatives. To obtain surface elevations from the extracted partials, integrations in Fourier space are performed, which leads to useful averaging. A scanning electron-microscope-based device was constructed to perform texture measurements. The design and construction of the BSE detection system, using Schottky barrier diodes, and of the detection hardware is presented. Calibration procedures, a means of correcting for scan distortions and the measurement of beam position drift, are also presented. The first application has included the measurement of a roughness standard. The BSE device was shown to possess spatial resolution superior to that of the stylus tracer