Angle Systems' Wafer Thickness Measurement System is designed to rapidly measure thickness on an array of wafers. This is accomplished by differential measurement with two laser triangulation sensors. The system uses interchangeable trays so that wafers of variable diameters can be measured. Programmable recipes are used such that wafers with different dimensions and measurement parameters can be inspected. The system takes multiple measurements at various location points in order to determine the thickness of the wafer. The number of points can be varied by changing the number of scan lines. The numerical results are displayed alongside a map that identifies wafers to be in or out of tolerances. Individual wafer plots showing curvature can be used to identify and correct problems that might be occurring in the manufacturing process.
