Positioning the wafer stage using white light interferometers

The white light interferoMETER IMS5600 from Micro-Epsilon is used for position monitoring of the wafer stage. It measures the XYZ movements of the stage with extremely high accelerations. The high-precision optical measuring system achieves a resolution in the nanometre range and ensures that the wafer is positioned to nanometre accuracy for exposure. Thanks to vacuum-suitable measuring heads, the measuring system can be used in a vacuum and is insensitive to strong magnetic fields.