公开(公告)号：DE3136887A1

公开(公告)日：1983-03-31

申请号：DE3136887

申请日：1981-09-17

Applicant: IBM DEUTSCHLAND

Inventor： BAYER THOMAS ,  KAUS GERHARD ,  KEMPF JUERGEN DIPL PHYS DR ,  SCHMID GERHARD DIPL PHYS DR

IPC: G01B11/06

Abstract: For the purpose of interferometric measurement of the thickness of a varying layer (10) made from opaque material, use is made of a reference beam (J2) which is reflected at a point of the opaque material which is protected against etching by a transparent layer (11). This reference beam is polarised in the plane of incidence, and is directed onto the transparent layer at the Brewster angle ( theta b). The measuring beam (J1) is polarised at right angles to the plane of incidence and is directed alternately onto the etched part of the opaque material and onto a point of the transparent layer, in order to determine the instantaneous thickness (tm) of the transparent layer (11), which is likewise etched. The instantaneous etched depth (ts) of the opaque material can be determined from the results of the two measuring steps.