公开(公告)号：EP0742895A4

公开(公告)日：1999-09-29

申请号：EP95942393

申请日：1995-11-03

Applicant: TENCOR INSTRUMENTS

Inventor： GROSS KENNETH P

IPC: G01N21/88 ,  G01N21/95 ,  G01N21/956 ,  G01N21/00

CPC classification number: G01N21/9501 ,  G01N21/8806

Abstract: An apparatus and method for inspecting a substrate (14), such as a semiconductor wafer, includes crossed cylindrical optical elements (44) that form an elliptical beam (40) that is caused to scan in parallel fashion at an oblique angle to the substrate (14). Preferably, the smaller dimension of the elliptical beam (40) is perpendicular to the direction of the scan of the beam across the wafer. A reflector (38) converts an angularly varying beam to a telecentrically scanning beam and also provides focusing only in the direction parallel to the telecentric scan.