Method for accurately detecting substrate surface removal thickness

The invention discloses a method for accurately detecting the removal thickness of the surface of a substrate, and belongs to the technical field of semiconductor materials. The detection method comprises the following steps: selecting a reference point on the surface of a substrate, and carrying out vertical marking by taking the reference point as a center to obtain a reference extension line; a test point is selected on the surface of the substrate, oblique marking is carried out with the test point as the center, a test extension line is obtained, and the plane containing the test extension line coincides with or is parallel to the plane containing the reference extension line; and measuring the horizontal displacement of the test extension line on the surface of the substrate before and after the substrate thickness removal process, and calculating the removal thickness of the surface of the substrate according to the horizontal displacement and the included angle between the test extension line and the