Patent Document ID: 9863889
Application ID: 12657089
Patent Status: 1

Claim One:
1. A method for capturing images of a wafer while the wafer is displaced along a scan motion path that positions the wafer relative to an inspection position beneath an objective lens such that each of a plurality of predetermined areas of the wafer is sequentially positioned within an inspection area, the method comprising: positioning a first area within the plurality of predetermined areas of the wafer within the inspection area as the wafer is displaced along the scan motion path; performing a wafer scanning process while the first area of the wafer remains within the inspection area during displacement of the wafer along the scan motion path, the wafer scanning process comprising: during a first time interval: (i) initiating exposure of a first image capture device, (ii) capturing a first image of the first area of a wafer at a first image capture position within the inspection area using the first image capture device, under a first contrast illumination supplied by way of a first flash or strobe, (iii) generating first image data using the first image capture device, and (iv) terminating exposure of the first image capture device after capture of the first image thereby terminating the first time interval; during a second time interval that begins immediately upon termination of the first time interval: (v) initiating exposure of a second image capture device, (vi) capturing a second image of the first area of the wafer at a second image capture position within the inspection area using the second image capture device, under a second contrast illumination supplied by way of a second flash or strobe, the second image having an image offset from the first image due to the wafer being spatially displaced by a predetermined distance between the capture of the first image and the capture of the second image, (vii) generating second image data using the second image capture device, and (viii) terminating exposure of the second image capture device after capture of the second image thereby terminating the second time interval; and correlating the first image and the second image by determining the image offset between the first image and the second image, positioning a second area within the plurality of predetermined areas of the wafer within the inspection area as the wafer is displaced along the scan motion path; repeating the wafer scanning process with respect to the second area of the wafer while the second area of the wafer remains within the inspection area during displacement of the wafer along the scan motion path, to thereby capture: a first image of the second area of the wafer at the first image capture position within the inspection area using the first image capture device under the first contrast illumination; and a second image of the second area of the wafer at the second image capture position within the inspection area using the second image capture device under the second contrast illumination, wherein a time difference between (a) positioning the first area of the wafer within the inspection area for capturing the first image of the first area of the wafer, and (b) positioning the second area of the wafer within the inspection area for capturing the first image of the second area of the wafer equals (i) a time required for exposing the first image capture device and capturing the first image of the first area of the wafer, plus (ii) a time required for converting the first image of the first area of the wafer into first image signals and transferring the first image signals to a database of storage memory, wherein the first and second image capture devices have an identical field of view within the inspection area for capturing the first and second images thereby, respectively.