Exposure control method and apparatus compensating for detection of offset from a measured value

An exposure apparatus for printing a pattern of an original onto a workpiece, said apparatus comprising:

• a light source for repeatedly providing pulsewise emission of light;
• an illumination optical system for illuminating the original with light emitted from said light source, to expose the workpiece to light passing through the original;
• a photoelectric converter for receiving at least a portion of the light emitted from said light source and passing through at least a portion of said illumination optical system, to produce an output based on photoelectric conversion of the received light, the output containing an offset from a measured value;
• and
• control means, comprising means for computing a difference between a first quantity corresponding to the offset of said converter and a second quantity corresponding to the offset-containing output produced by said converter, and comprising means for controlling the amount of exposure of the workpiece on the basis of the computed difference.

An exposure control method for use with an exposure apparatus including a pulsewise emission type light source for emitting light and a photoelectric converter for receiving light emitted from the light source, said method comprising the steps of:

• illuminating an original having a pattern thereon with light emitted from the light source to expose a workpiece, onto which the pattern of the original is to be printed, to light passing through the original;
• receiving, through the photoelectric converter, at least a portion of the light emitted from the light source, such that the photoelectric converter produces an output based on photoelectric conversion of the received light;
• detecting offset from a measured value contained in the output produced by the photoelectric converter;
• computing a difference between a first quantity corresponding to the offset of the photoelectric converter and a second quantity corresponding to the offset-containing output produced by the photoelectric converter;
• and
• controlling the amount of exposure time of the workpiece on the basis of the computed difference.

A method of exposing a mask and a wafer in the manufacture of semiconductor devices to light emitted from a pulsewise emission type light source, said method comprising the steps of:

• detecting light emitted from the light source using a photodetector and producing a photodetector output;
• detecting offset from a measured value contained in the photodetector output;
• detecting a difference between a first quantity corresponding to the offset of the photodetector and a second quantity corresponding to the offset-containing output of the photodetector;
• and
• exposing the mask and the wafer to the light emitted from the light source, while controlling the exposure on the basis of the detected difference.