公开(公告)号：WO1993023734A1

公开(公告)日：1993-11-25

申请号：PCT/US1993004153

申请日：1993-05-03

Applicant: TENCOR INSTRUMENTS

Inventor： TENCOR INSTRUMENTS ,  GALBRAITH, Lee, K. ,  VAUGHT, John, L. ,  WOLF, Ralph, C. ,  LESLIE, Brian ,  NEUKERMANS, Armand, P.

IPC: G01N21/00

CPC classification number: G02F1/134309 ,  G01N21/95623 ,  G01N2201/067 ,  G02B27/46

Abstract: An inspection apparatus for a light diffracting surface (w) employs a planar array of individually addressable light valves (69; 82; 84) for use as a spatial filter in an imaged Fourier plane of a diffraction pattern, with valves having stripe geometry (91; 93; 95) corresponding to positions of members (81; 83; 85) of the diffraction pattern, blocking light from those members. The remaining valve stripes, i.e. those not blocking light from diffraction order members, are open for transmission of light. Light (13; 31) directed onto the surface (w), such as a semiconductor wafer, forms elongated curved diffraction orders (65) from repetitive patterns of circuit features. The curved diffraction orders are transformed to linear orders by a Fourier transform lens (35a; 35b). The linear diffraction orders from repetitive patterns of circuit features are blocked, while light from non-repetitive features, such as dirt particles or defects, is allowed to pass through the light valves to a detector (47).