公开(公告)号：US5155372A

公开(公告)日：1992-10-13

申请号：US797877

申请日：1991-11-26

申请人： Arlen J. Bowen ,  David L. Erickson ,  Daniel W. Jewell ,  Venkat R. Koka

发明人： Arlen J. Bowen ,  David L. Erickson ,  Daniel W. Jewell ,  Venkat R. Koka

IPC分类号： G02B27/46 ,  G01N21/93 ,  G01N21/94 ,  G01N21/95 ,  G01N21/956

CPC分类号： G01N21/95623

摘要： The present invention includes a system for monitoring surface structures on a planar surface utilizing a radiation source emitting a beam. The planar surface has various surface structure types, including a plurality of grooves therein which intersect at various angles which are equal to or less than a predetermined maximum angle. The system includes an apparatus for directing the beam to the planar surface along an optical axis perpendicular to the planar surface resulting in radiation being scattered from the planar surface and a reference beam being specularly reflected from the planar surface. The system also includes detector responsive to radiation scattered from the planar surface. This detector produces a first signal representative thereof. Also provided is a spatial filter for filtering radiation scattered from the planar surface to allow only radiation from at least selected one of the plurality of surface structure types to reach the detector responsive to radiation scattered from the planar surface. The system may also include a detector responsive to the reference beam, producing a second signal in response to the reference beam and a circuit for producing a final signal from the first signal and the second signal.

摘要翻译： 本发明包括一种利用发射光束的辐射源监测平面上的表面结构的系统。 该平坦表面具有各种表面结构类型，其中包括多个凹槽，该多个凹槽以等于或小于预定最大角度的各种角度相交。 该系统包括用于沿着垂直于平面表面的光轴将光束引导到平面表面的装置，导致从平面表面散射的辐射和从平面表面镜面反射的参考光束。 该系统还包括响应于从平面表面散射的辐射的检测器。 该检测器产生代表其的第一信号。 还提供了一种空间滤波器，用于对从平面表面散射的辐射进行滤波，以允许来自多个表面结构类型中的至少一个的至少一个的辐射响应于从平面表面散射的辐射而到达检测器。 系统还可以包括响应于参考光束的检测器，响应于参考光束产生第二信号，以及用于从第一信号和第二信号产生最终信号的电路。