Prior Scientific ProScan III Manual page 87

ProScan® III Manual
IST is a system where the stage movement is analysed during the production process and
errors in metric accuracy recorded. Metric errors in stages tend to be linear in form, so
the metric error is mapped to a straight line. The description of the straight line, the
gradient and offset is stored on a chip on the stage itself. This is done for both axes
creating four numbers, hence the common description 4 point mapping. Prior products
are Plug and Play, i.e., any product can be attached to any controller and the information
about the stage is loaded into the controller. This makes Prior systems very flexible, and
easy to set up.
Stage Mapping takes the IST one step further and does not assume that any errors in the
stage are linear. The mapping is in 1mm square grid pattern, i.e., it generates 4 numbers
for each 1mm square of the stage. The significantly enhances metric accuracy.
© Prior Scientific Instruments Ltd Version 1.12 June 2017 Page 85