Image modeling and restoration for scanning probe microscopy.

Scanning Probe Microscopes (SPMs), which include the Scanning Tunneling Microscope (STM) and the Atomic Force Microscope (AFM), are becoming increasingly popular for three-dimensional (3D) metrology in the semiconductor industry and for high resolution 3D imaging of surfaces in materials science and biology. A serious problem in SPM imaging is that the image is distorted due to the interaction of the topography of the scanning probe with that of the scanned sample. This dissertation presents a computational model of the nonlinear geometric interactions of the scanning probe and the scanned sample in SPM imaging. The model serves as the basis of tools for simulation and visualization of SPM imaging. Such tools are invaluable in designing probe geometries and in selecting a probe geometry for a sample of interest. The model is expressed in terms of gray scale mathematical morphology. Image restoration techniques are formulated to obtain a better estimate of the true surface scanned, given the SPM image and the shape of the probe used for scanning. Measures are developed for indicating the parts of an SPM image that represent reliable data. The image restoration techniques are shown to be a compulsory preprocessing step for SPM images in any application. The dissertation also presents a calibration technique for recovering the three-dimensional shape and orientation of the probe in situ from the image of a calibration pattern. The probe shape recovered in this fashion can be used as an input to the image restoration techniques. The orientations of the sample and the probe are important parameters in SPM imaging. Background plane rotation, rather than background plane subtraction, is shown to be the appropriate technique for compensating an SPM image for sample orientation. It is shown that a better estimate of the true surface can be obtained by imaging the sample at several orientations and combining information from multiple images.PhDComputer Science and EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/104018/1/9423291.pdfDescription of 9423291.pdf : Restricted to UM users only