TDI Sensor in a Darkfield System

An wafer inspection apparatus comprising:

• an illumination system configured to illuminate a field of a moving wafer;
• an image collection system configured to collect light from the moving wafer;
• a beam splitter configured to split the collected light into a first image stream and a second image stream;
• a first time-delay integration device configured to receive and delay the first image stream by a duration corresponding to a linear speed of the moving wafer;
• a second time-delay integration device configured to receive and delay the second image stream by a duration corresponding to a linear speed of the moving wafer;
• and
• an image processing element configured to produce a first wafer image from the first delayed image stream and a second wafer image from the second delayed image stream.

A wafer imaging device comprising:

• an illumination means for illuminating a moving wafer;
• an image collection means for collecting scattered light from the moving wafer;
• a beam splitting means for splitting the collected scattered light into a first image stream and a second image stream;
• a first time-delay imaging means for receiving and delaying the first image stream by a duration corresponding to a linear speed of the moving wafer;
• a second time-delay imaging means for receiving and delaying the second image stream by a duration corresponding to a linear speed of the moving wafer;
• and
• an image processing means for producing a first wafer image base on the first delayed image stream and a second wafer image based on the second delayed image stream.