Patent ID: 8860946
Filing Date: 2014-10-14
Classification: G01B

Abstract:
1. A method for measuring the surface of a specimen, including the steps of: positioning a measuring area of said specimen under a probe, the probe being affixed to an actuator; positioning the probe to be in contact with the specimen; increasing a contact force between the probe and the specimen, until the contact force is detected as reaching a predetermined set contact force; separating a light beam from a light source into a first light beam and a second light beam; irradiating said first light beam onto a target mirror attached on said actuator, thereby generating a light beam reflected from said target mirror attached on said actuator; synthesizing said second light beam with said light beam reflected from said actuator; dividing the synthesized light beam into a plurality of light beams; phase shifting at least one of the plurality of light beams, by use of a plurality of phase shift elements, thereby producing interfered light beams, wherein the plurality of phase shift elements include: a first phase shift element divided into an upper part and a lower part having different crystal orientations respectively, and a second phase shift element divided into a left part and a right part having different crystal orientations respectively; and detecting the movement amount of said actuator based on said interfered light beams.