System and method for inspecting a wafer

Abstract

An inspection system for inspecting a semiconductor wafer. The inspection system comprises an illumination setup for supplying broadband illumination. The broadband illumination can be of different contrasts, for example brightfield and darkfield broadband illumination. The inspection system further comprises a first image capture device and a second image capture device, each configured for receiving broadband illumination to capture images of the semiconductor wafer while the semiconductor wafer is in motion. The system comprises a number of tube lenses for enabling collimation of the broadband illumination. The system also comprises a stabilizing mechanism and an objective lens assembly. The system further comprises a thin line illumination emitter and a third image capture device for receiving thin line illumination to thereby capture three-dimensional images of the semiconductor wafer. The system comprises a reflector assembly for enabling the third image capture device to receive illumination reflected from the semiconductor wafer in multiple directions.

1 . An inspection system comprising:
 an illuminator configured for supplying incident illumination to an inspection position on a surface of an article under inspection;   a plurality of optical elements comprising a first reflector assembly configured for capturing dispersed illumination reflected in multiple directions from the surface of the article under inspection and the first reflector assembly being further configured for directing the captured dispersed illumination along a plurality of optical paths to provide a plurality of views of the surface of the article under inspection; and   an image capture device configured to receive the captured dispersed illumination that provides the plurality of views of the surface of the article under inspection as a single exposure.   
     
     
         2 . The system of  claim 1 , wherein the illumination incident on the surface of the article under inspection is directed thereto by a second reflector assembly, the second reflector assembly comprising at least one reflector. 
     
     
         3 . The system of  claim 1 , wherein the first reflector assembly comprises at least one of a beam splitter, mirror, a prism and a reflective surface. 
     
     
         4 . The system of  claim 1 , wherein the first reflector assembly comprises a first reflecting structure and a second reflecting structure arranged for capturing dispersed illumination reflected from the surface of the article under inspection and directing the captured dispersed illumination along a first optical path and a second optical path respectively. 
     
     
         5 . The system of  claim 1 , wherein the plurality of optical elements further includes at least one objective lens configured for collimating the illumination directed along the plurality of optical paths. 
     
     
         6 . The system of  claim 1 , wherein the plurality of optical elements further includes at least one tube lens configured for focusing the captured dispersed illumination directed along the plurality of optical paths onto the image capture device. 
     
     
         7 . The system of  claim 6 , wherein the tube lens facilitates introduction of additional optical components into the system. 
     
     
         8 . The system of  claim 1 , wherein the illuminator comprises a thin line illuminator. 
     
     
         9 . The system of  claim 8 , wherein the thin line illuminator comprises a laser. 
     
     
         10 . The system of  claim 1 , wherein the plurality of views of the surface of the article under inspection provides or corresponds to a 3D profile of the surface of the article under inspection at the inspection position. 
     
     
         11 . The system of  claim 1 , wherein the image capture device is configured for converting the single exposure of the plurality of views of the surface of the article under inspection to image signals, and where the system further comprises a processing unit configured for receiving and processing the image signals. 
     
     
         12 . The system of  claim 11 , wherein processing the image signals facilitates a 3D inspection process performed upon the surface of the article under inspection. 
     
     
         13 . The system of  claim 1 , wherein the image capture device is configured for capturing as a single exposure the plurality of views of the surface of the article under inspection while the article under inspection is in motion. 
     
     
         14 . The system of  claim 1 , wherein the image capture device comprises a 3D profile camera. 
     
     
         15 . A method of inspection comprising:
 supplying incident illumination to an inspection position on a surface of an article under inspection by an illuminator;   transmitting dispersed illumination reflected in multiple directions from the surface of the article under inspection along a plurality of optical paths to provide a plurality of views of the surface of the article under inspection, the transmitting facilitated by a plurality of optical elements; and   capturing as a single exposure the plurality of views of the surface of the article under inspection by an image capture device.   
     
     
         16 . The method of inspection as in  claim 15 , wherein transmitting dispersed illumination reflected in multiple directions from the surface of the article under inspection along a plurality of optical paths to provide a plurality of views of the surface of the article under inspection comprises:
 capturing dispersed illumination reflected in multiple directions from the surface of the article under inspection by the plurality of optical elements; and   directing the captured dispersed illumination along the plurality of optical paths to provide the plurality of views of the surface of the article under inspection by the plurality of optical elements.   
     
     
         17 . The method of inspection as in  claim 15 , wherein the plurality of optical elements comprises a first reflector assembly and wherein the first reflector assembly comprises at least one of a beam splitter, mirror, a prism and a reflective surface. 
     
     
         18 . The method of inspection as in  claim 15 , wherein transmitting the dispersed illumination reflected in multiple directions from the surface of the article under inspection along the plurality of optical paths comprises transmitting the dispersed illumination reflected in multiple directions from the surface of the article under inspection along a first optical path and a second optical path. 
     
     
         19 . The method of inspection as in  claim 18 , wherein
 the plurality of optical elements comprises an objective lens; and   transmitting the dispersed illumination reflected in multiple directions from the surface of the article under inspection along the first optical path and the second optical path comprises collimating the dispersed illumination reflected along the first optical path and the second optical path by the objective lens.   
     
     
         20 . The method of inspection as in  claim 18 , wherein
 the plurality of optical elements comprises a tube lens; and   transmitting the dispersed illumination reflected in multiple directions from the surface of the article under inspection along the first optical path and the second optical path comprises focusing the dispersed illumination reflected along the first optical path and the second optical path by the tube lens.   
     
     
         21 . The method of inspection as in  claim 15 , wherein supplying incident illumination to the inspection position on the surface of the article under inspection by the illuminator comprises supplying incident illumination to the inspection position on the surface of the article under inspection by a thin line illuminator. 
     
     
         22 . The method of inspection as in  claim 21 , wherein supplying incident illumination to the inspection position on the surface of the article under inspection by a thin line illuminator comprises supplying incident illumination to the inspection position on the surface of the article under inspection by a laser. 
     
     
         23 . The method of inspection as in  claim 15 , wherein capturing as a single exposure the plurality of views of the surface of the article under inspection by the image capture device comprises capturing as a single exposure a 3D profile of the surface of the article under inspection by the image capture device. 
     
     
         24 . The method of inspection as in  claim 15 , further comprising:
 converting the single exposure of the plurality of views to image signals by the image capture device.   
     
     
         25 . The method of inspection as in  claim 24 , further comprising:
 receiving and processing the image signals by a processing unit.   
     
     
         26 . The method of inspection as in  claim 15 , wherein capturing the plurality of the views of the surface of the article under inspection as a single exposure by the image capture device is performed when the article under inspection is in motion.