Response surface prediction from a spatial montoring process

We present an approach that selects a sub-grid from an in monitoring map according to the criterion\r\nof spatial optimal coverage of the wafer surface (see also Walvoort,\r\n2010). This approach may also include expert knowledge about those\r\nareas where production is less precise because of unavoidable technical\r\nreasons and hence may indicate where a higher sampling density must\r\nbe assured. If sampling measures are available, a validation procedure\r\ncan be used to select the best sub-map based for instance on the prediction\r\nerror, by comparing the results obtained using the full and the\r\nreduced grid.