CAMERA LINEARITY TEST STRUCTURE
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2002-Jan-15
Some defect/particle detection systems designed for semiconductor applications arc based on a combination of a vision sub-system (video camera with lens), an accu- rate x-y translation sub-system (stage) that steps the semi- conductor wafer beneath the camera and a computer system which controls the equipment and stores meas- urement information. Particle detection is accomplished by measuring optical scattering of laser light from parti- cles that rest on the surface of the wafer. Digitization of the video camera image offers the ability to obtain locational information on the position of the defects within the field of view of the camera. Proper calibration of the vision system combined with accurate locational data from the x-y stage allows the determination of x-y coor- dinates for each particle detected on the wafer being examined with reference to a coordinate system arbi- trarily defined on the wafer, typically near the wafer cen- ter. Tbis particle coordinate locational data, along with the wafer, is then transferable to other analysis equip- ment for further characterization of the physical and chemical nature of the defects.