Shape measuring method, shape measuring apparatus, program, recording medium, method of manufacturing optical element, and optical element

A shape measuring apparatus for measuring a shape of an object surface of an object, comprising:

• a light source for irradiating a measuring beam onto an object surface of an object;
• a first stage that scans the object with respect to the measuring beam;
• a second stage that moves the object in a direction that is different to a drive direction of the first stage;
• a detecting unit that detects a wavefront of reflected light from the object surface;
• and
• a controlling unit configured to control the first stage and the second stage to measure a shape of the object surface, wherein
• the object surface is moved along a trajectory that is previously set, the light source irradiates a measuring beam sequentially onto a plurality of partial regions of the object surface, the detecting unit detects wavefronts of reflected light from each of the plurality of partial regions by a detecting unit;
• and the controlling unit calculates partial shape data of the plurality of partial regions based on the wavefronts and stitch the partial shape data,
• the controlling unit controls the first stage to move the object surface to at least two positions along the drive direction that are less than a number of a plurality of measurement positions along the drive directions to which the object surface is moved when detecting a wavefront of reflected light of each of the plurality of partial regions by means of the detecting unit,
• the controlling unit actually measures respective placement errors with respect to the trajectory of the object surface at the at least two positions based on wavefronts detected by the detecting unit in states in which the first stage is controlled to each of the at least two positions,
• the controlling unit estimates respective placement errors with respect to the trajectory of the object surface with regard to positions of the first stage other than the at least two positions among the plurality of measurement positions based on the placement errors that are actually measured by the actual measuring, and,
• before each detection at a time of detecting respective wavefronts of reflected light from the plurality of partial regions by means of the detecting unit for calculating the partial shape data, the controlling unit controls the first stage to the measurement position and controls the second stage to a position that cancels out a placement error at the measurement position, to thereby align the object surface.

A non-transitory computer-readable recording medium storing a readable program for operating a computer to execute a shape measuring method for measuring a shape of an object surface of an object by:

• controlling, by means of a controlling unit, a first stage that scans the object having the object surface in a drive direction and a second stage that moves the object in a direction that is different from the drive direction of the first stage, to thereby move the object surface along a trajectory that is previously set;
• irradiating a measuring beam sequentially onto a plurality of partial regions of the object surface;
• detecting wavefronts of reflected light from each of the plurality of partial regions by a detecting unit;
• and using the controlling unit to calculate partial shape data of the plurality of partial regions based on the wavefronts, and stitch the partial shape data;
• the shape measuring method comprising:
• moving in which the controlling unit controls the first stage to move the object surface to at least two positions along the drive direction that are less than a number of a plurality of measurement positions along the drive directions to which the object surface is moved when detecting a wavefront of reflected light of each of the plurality of partial regions by means of the detecting unit;
• actual measuring in which the controlling unit actually measures respective placement errors with respect to the trajectory of the object surface at the at least two positions based on wavefronts detected by the detecting unit in states in which the first stage is controlled to each of the at least two positions;
• estimating in which the controlling unit estimates respective placement errors with respect to the trajectory of the object surface with regard to positions of the first stage other than the at least two positions among the plurality of measurement positions based on the placement errors that are actually measured by the actual measuring;
• and
• aligning in which, before each detection at a time of detecting respective wavefronts of reflected light from the plurality of partial regions by means of the detecting unit for calculating the partial shape data, the controlling unit controls the first stage to the measurement position and controls the second stage to a position that cancels out a placement error at the measurement position, to thereby align the object surface.

A manufacturing method of an optical element comprising:

• forming a shape of an optical element;
• and
• examining the optical element, based on a result of measuring a shape of the optical element, wherein the measuring the shape of the optical element is performed by:
• controlling, by means of a controlling unit, a first stage that scans the optical element having the optical element surface in a drive direction and a second stage that moves the object in a direction that is different from the drive direction of the first stage, to thereby move the object surface along a trajectory that is previously set;
• irradiating a measuring beam sequentially onto a plurality of partial regions of the optical element surface;
• detecting wavefronts of reflected light from each of the plurality of partial regions by a detecting unit;
• and using the controlling unit to calculate partial shape data of the plurality of partial regions based on the wavefronts, and stitch the partial shape data;
• the shape measuring method comprising:
• moving in which the controlling unit controls the first stage to move the optical element surface to at least two positions along the drive direction that are less than a number of a plurality of measurement positions along the drive directions to which the optical element surface is moved when detecting a wavefront of reflected light of each of the plurality of partial regions by means of the detecting unit;
• actual measuring in which the controlling unit actually measures respective placement errors with respect to the trajectory of the object surface at the at least two positions based on wavefronts detected by the detecting unit in states in which the first stage is controlled to each of the at least two positions;
• estimating in which the controlling unit estimates respective placement errors with respect to the trajectory of the optical element surface with regard to positions of the first stage other than the at least two positions among the plurality of measurement positions based on the placement errors that are actually measured by the actual measuring;
• and
• aligning in which, before each detection at a time of detecting respective wavefronts of reflected light from the plurality of partial regions by means of the detecting unit for calculating the partial shape data, the controlling unit controls the first stage to the measurement position and controls the second stage to a position that cancels out a placement error at the measurement position, to thereby align the object surface.

A an optical element manufactured according to a manufacturing method comprising:

• forming a shape of an optical element;
• and
• examining the optical element, based on a result of measuring a shape of the optical element, wherein the measuring the shape of the optical element is performed by:
• controlling, by means of a controlling unit, a first stage that scans the optical element having the optical element surface in a drive direction and a second stage that moves the object in a direction that is different from the drive direction of the first stage, to thereby move the object surface along a trajectory that is previously set;
• irradiating a measuring beam sequentially onto a plurality of partial regions of the optical element surface;
• detecting wavefronts of reflected light from each of the plurality of partial regions by a detecting unit;
• and using the controlling unit to calculate partial shape data of the plurality of partial regions based on the wavefronts, and stitch the partial shape data;
• the shape measuring method comprising:
• moving in which the controlling unit controls the first stage to move the optical element surface to at least two positions along the drive direction that are less than a number of a plurality of measurement positions along the drive directions to which the optical element surface is moved when detecting a wavefront of reflected light of each of the plurality of partial regions by means of the detecting unit;
• actual measuring in which the controlling unit actually measures respective placement errors with respect to the trajectory of the object surface at the at least two positions based on wavefronts detected by the detecting unit in states in which the first stage is controlled to each of the at least two positions;
• estimating in which the controlling unit estimates respective placement errors with respect to the trajectory of the optical element surface with regard to positions of the first stage other than the at least two positions among the plurality of measurement positions based on the placement errors that are actually measured by the actual measuring;
• and
• aligning in which, before each detection at a time of detecting respective wavefronts of reflected light from the plurality of partial regions by means of the detecting unit for calculating the partial shape data, the controlling unit controls the first stage to the measurement position and controls the second stage to a position that cancels out a placement error at the measurement position, to thereby align the object surface.