Surface position detecting system and method

A surface position detecting system for detecting a surface position of a substrate, said system comprising:

• a plurality of sensors for measuring surface position at plural locations on the substrate, while relatively scanning the substrate;
• discriminating means for discriminating and memorizing, beforehand, effectiveness/ineffectiveness of each sensor at each measurement point during scanning measurement, on the basis of information related to the substrate processing;
• and
• calculating means for selecting, during scan measurement, one or those of the sensors of effective measured value on the basis of the discrimination information and for calculating the surface information of the substrate on the basis of measurement output of the one or those sensors.

A surface position detecting method wherein a plurality of sensors for measuring surface position of a substrate at plural locations while relatively scanning the substrate are used to detect a surface position corresponding to the measurement locations on the substrate, said method comprising the steps of:

• discriminating, beforehand, effectiveness/ineffectiveness of a measured value at each measurement location by a corresponding sensor during the scan measurement, on the basis of information related to the substrate processing;
• switching, during the scan measurement, sensors to be used for the measurement, dynamically, on the basis of the information of discrimination;
• and
• calculating the surface information of the substrate on the basis of measurement output of the switched sensor or sensors.

An exposure method wherein a pattern of an original and a slit are projected on to a substrate through a projection optical system, wherein the original and the substrate are relatively scanned relative to the projection optical system in a direction perpendicular to a lengthwise direction of the slit whereby the pattern of the original is transferred on to the substrate, and wherein a plurality of sensors for measuring surface position of the substrate at plural locations are used to detect surface position corresponding to the measurement locations on the substrate, said method comprising the steps of:

• discriminating, beforehand, effectiveness/ineffectiveness of a measured value of each of the measurement points of the sensors during the scan measurement, on the basis of information related to the substrate processing;
• switching, during the scan measurement, sensors to be used for the measurement, on the basis of the information of discrimination;
• calculating the surface information of the substrate on the basis of a measured output of the switched sensor or sensors;
• and
• determining, on the basis of the information of discrimination, the order of shot processing so that, with regard to a shot with respect to which the number of effective sensors changes along the scan direction within that shot, the scan is done in a direction from a larger effective sensor number side to a smaller effective sensor number side.