Patent ID: 8422028
Filing Date: 2013-04-16
Classification: G01B

Abstract:
1. A scanning microscope using an I/Q-interferometer, comprising: an I/Q-interferometer, from which a probe beam is coupled out, to which a reflected beam from a surface or transmitted beam through a sample is coupled back, in which I/Q-demodulation on interference signals are performed, and by which I- and Q-signals are obtained; an XY scanner scanning the sample in two directions perpendicular to a propagation direction of the probe beam; a scanner driver actuating the XY scanner; a precision motion stage controlling the displacement of the sample along the direction parallel to the direction of the probe beam; a motion stage driver actuating the precision motion stage; a focusing device focusing the probe beam from the I/Q interferometer onto a surface or inside of the sample; a collimating device collimating the probe beam reflected from or transmitted through the sample; and a computer transferring control commends to the scanner driver for moving XY scanner from one scanning point to the next scanning point in a direction perpendicular to the propagation direction of the probe beam, receiving, storing, and processing the I- and Q-signals, demodulating phase and amplitude changes induced on the probe beam, wherein the computer measures phase change in each scanning point, calculates an error signal for a feedback control for a constant phase scanning, transfers commends to the motion stage driver for the precision motion stage to compensate for height changes during the constant phase scanning, obtains true morphology of the sample from the error signal, and obtains a map of material inhomogeneity from amplitude measurements, wherein the computer finds out a scanning point, at which an amplitude signal is largest in the scanning result, and connects scanning points which have the same phase as the scanning point with largest amplitude to obtain a contour line or a contour surface.