Measurement apparatus to calculate wavefront aberration of optical system using shearing interference fringes, exposure apparatus, and method of manufacturing device

An exposure apparatus for projecting a pattern of a reticle onto a substrate via a projection optical system to expose the substrate, the apparatus comprising:

• a measurement apparatus for measuring a wavefront aberration of an optical system to be measured, the measurement apparatus comprising:
• a light source;
• a first optical system arranged in an optical path from said light source to the optical system to be measured, and configured to reflect a certain component of a light beam emitted by said light source by a final surface thereof and transmit a remaining component of the light beam emitted by said light source through the final surface;
• a reflecting surface configured to reflect a light beam including the remaining component transmitted through said first optical system and the optical system to be measured;
• a diffraction grating configured to:
• generate first laterally shifted wavefronts from the certain component reflected by the final surface and generate a first shearing interference fringe by interfering the first laterally shifted wavefronts, each of the first laterally shifted wavefronts having an aberration of the first optical system;
• and
• generate second laterally shifted wavefronts from the remaining component reflected by the reflecting surface and generate a second shearing interference fringe by interfering the second laterally shifted wavefronts, each of the second laterally shifted wavefronts having an aberration of the first optical system and the optical system to be measured;
• a changing mechanism configured to change a tilt of the final surface or a tilt of said reflecting surface for shifting a first phase of the certain component reflected by the final surface;
• a driving mechanism configured to drive the diffraction grating for shifting the first phase and a second phase of the remaining component reflected by said reflecting surface at the same velocity;
• a controller configured to control said changing mechanism and said driving mechanism so that the first phase and the second phase are each shifted at a different velocity;
• an image sensing unit configured to sense both the first shearing interference fringe and the second shearing interference fringe generated by said diffraction grating while shifting the first phase and the second phase each at the different velocity;
• and
• an arithmetic unit configured to calculate, a wavefront aberration of said first optical system and a wavefront aberration of both said first optical system and the optical system to be measured, using data on both the first shearing interference fringe and the second shearing interference fringe sensed by said image sensing unit, and calculate a wavefront aberration of the optical system to be measured based on the two calculated wavefront aberrations.

A method of manufacturing a device, the method comprising the steps of:

• exposing a substrate to radiant energy using an exposure apparatus;
• developing the exposed substrate;
• and
• processing the developed substrate to manufacture the device,
• wherein the exposure apparatus comprises a measurement apparatus configured to measure a wavefront aberration of a projection optical system as an optical system to be measured, and
• wherein the measurement apparatus comprises:
• a light source;
• a first optical system arranged in an optical path from the light source to the optical system to be measured, and configured to reflect a certain component of a light beam emitted by the light source by a final surface thereof and transmit a remaining component of the light beam emitted by the light source through the final surface;
• a reflecting surface configured to reflect a light beam including the remaining component transmitted through the first optical system and the optical system to be measured;
• a diffraction grating configured to:
• generate first laterally shifted wavefronts from the certain component reflected by the final surface and generate a first shearing interference fringe by interfering the first laterally shifted wavefronts, each of the first laterally shifted wavefronts having an aberration of the first optical system;
• and
• generate second laterally shifted wavefronts from the remaining component reflected by the reflecting surface and generate a second shearing interference fringe by interfering the second laterally shifted wavefronts, each of the second laterally shifted wavefronts having an aberration of the first optical system and the optical system to be measured;
• a changing mechanism configured to change a tilt of the final surface or a tilt of said reflecting surface for shifting a first phase of the certain component reflected by the final surface;
• a driving mechanism configured to drive the diffraction grating for shifting the first phase and a second phase of the remaining component reflected by said reflecting surface at the same velocity;
• a controller configured to control said changing mechanism and said driving mechanism so that the first phase and the second phase are each shifted at a different velocity;
• an image sensing unit configured to sense both the first shearing interference fringe and the second shearing interference fringe generated by the diffraction grating while shifting the first phase and the second phase each at the different velocity;
• and
• an arithmetic unit configured to calculate, a wavefront aberration of the first optical system and a wavefront aberration of both the first optical system and the optical system to be measured, using data on both the first shearing interference fringe and the second shearing interference fringe sensed by the image sensing unit, and calculate a wavefront aberration of the optical system to be measured based on the two calculated wavefront aberrations.

A measurement apparatus for measuring a wavefront aberration of an optical system to be measured, the apparatus comprising:

• an optical member configured to:
• generate first laterally shifted wavefronts from the certain component reflected by the final surface and generate a first shearing interference fringe by interfering the first laterally shifted wavefronts, each of the first laterally shifted wavefronts having an aberration of the first optical system;
• and
• generate second laterally shifted wavefronts from the remaining component reflected by said reflecting surface and generate a second shearing interference fringe by interfering the second laterally shifted wavefronts, each of the second laterally shifted wavefronts having an aberration of the first optical system and the optical system to be measured;
• a changing mechanism configured to change a tilt of the final surface or a tilt of said reflecting surface for shifting a first phase of the certain component reflected by the final surface;
• a driving mechanism configured to drive the optical member for shifting the first phase and a second phase of the remaining component reflected by said reflecting surface at the same velocity;
• a controller configured to control said changing mechanism and said driving mechanism so that the first phase and the second phase are each shifted at a different velocity;
• an image sensing unit configured to sense both the first shearing interference fringe and the second shearing interference fringe generated by said optical member while shifting the first phase and the second phase each at the different velocity;
• and
• an arithmetic unit configured to calculate, a wavefront aberration of said first optical system and a wavefront aberration of both said first optical system and the optical system to be measured, using data on both the first shearing interference fringe and the second shearing interference fringe sensed by said image sensing unit, and calculate a wavefront aberration of the optical system to be measured based on the two calculated wavefront aberrations.