Patent ID: 8024963
Filing Date: 2011-09-27
Classification: G01Q

Abstract:
1. A method of operating an atomic force microscope which processes a sample, comprising: using a feedback loop to control a distance between a base of a cantilever of the atomic force microscope which has a probe tip, and a surface of the sample to maintain the probe tip of the cantilever in a pre-established relationship with respect to the surface of the sample while scanning the sample by creating relative movement between the probe tip of the cantilever and the sample; exciting a chip of the cantilever at two or more synthesized frequencies that have been summed together by a circuit element; providing each of said synthesized frequencies as a reference signal to a lock-in amplifier; and measuring cantilever values, including the amplitude and phase of the cantilever at the different excitation frequencies; and using the measured cantilever values to provide information indicative of a surface of the sample.