Additionally, WAFERMAP allows for the selection of the measurement value at one of 5 predefined points on the wafer. These points may be actual measurement sites, or they can be an interpolated location. This WAFERMAP option allows for the comparison of the same site for all loaded wafers (e.g. the site in the center of the wafer).
The user can also choose the sorting criterion. This criterion can be a numerical value or some of the non-numerical values (e.g. the "Fab name" or the "Equipment info" from the wafer remarks). One use of this technique is to sort the data by tool characteristics.
The upper and lower control limits (UCL, LCL), and the sigma ranges (±1, ±2, ±3 sigma) are shown as horizontal lines on the plot if they are located within the plotted range.
On the right side of the plot area, the statistical analysis of the displayed value (Special Measure Statistics) is given in the form of a histogram. If for example, the displayed criterion is the mean, the histogram will show the distribution of the mean values of all selected wafers.
Single clicking on any marker of a displayed wafer brings up the Single Wafer Statistics for this wafer on the left side of the screen.
