Method of measuring aberration of a projection system of a lithographic apparatus, device manufacturing method, and device manufactured thereby
AssigneeASML Netherlands B.V.
InventorHans Van Der Laan
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Abstract
A method of determining aberration of a projection system according to one embodiment of the invention includes using a test pattern to pattern a projection beam of radiation, using the projection system to project the patterned beam, and directly measuring an aerial image of the test pattern as formed by the projection system. The test pattern includes a two-dimensional lattice comprising a plurality of unit cells, each unit cell including at least three isolated areas. At least one of a transmissivity, a reflectivity, and a phase-shifting property of the isolated areas is substantially different from that of a remainder of the area of the unit cell.
Claims22
A method of determining aberration of a projection system, said method comprising:
- supplying a projection beam of radiation;
- using a test pattern to pattern the projection beam;
- using the projection system to project the patterned beam;
- at each of a plurality of different illumination settings, directly measuring an aerial image of the test pattern as formed by the projection system to obtain a corresponding value of each of at least one parameter;
- and
- based on the corresponding values, calculating at least one coefficient relating to aberration of the projection system,
- wherein the test pattern includes a two-dimensional lattice comprising a plurality of unit cells, each unit cell including at least three isolated areas, and
- wherein at least one of a transmissivity, a reflectivity, and a phase-shifting property of the isolated areas is substantially different from that of a remainder of the area of the unit cell.
A method of manufacturing a device, said method comprising:
- supplying a projection beam of radiation;
- using a test pattern to pattern the projection beam;
- using the projection system to project the beam patterned using the test pattern;
- at each of a plurality of different illumination settings, directly measuring an aerial image of the test pattern as formed by the projection system to obtain a corresponding value of each of at least one parameter;
- based on the corresponding values, calculating at least one coefficient relating to aberration of the projection system;
- using a patterning structure to pattern the projection beam;
- and
- using a projection system to project the beam patterned using the patterning structure onto a target portion of a layer of radiation-sensitive material that at least partially covers a substrate,
- wherein said using a projection system to project the beam patterned using the patterning structure includes, based on the at least one coefficient, correcting for aberration of the projection system, and
- wherein the test pattern includes a two-dimensional lattice comprising a plurality of unit cells, each unit cell including at least three isolated areas, and
- wherein at least one of a transmissivity, a reflectivity, and a phase-shifting property of the isolated areas is substantially different from that of a remainder of the area of the unit cell.
A method of determining aberration of a projection system, said method comprising:
- supplying a projection beam of radiation;
- using a test pattern to pattern the projection beam;
- using the projection system to project the patterned beam;
- directly measuring an aerial image of the test pattern as formed by the projection system to obtain a corresponding value of each of at least one parameter;
- and
- based on the at least one corresponding value, calculating at least one coefficient relating to aberration of the projection system,
- wherein the test pattern includes a two-dimensional lattice comprising a plurality of unit cells, each unit cell including at least three isolated areas, and
- wherein at least one of a transmissivity, a reflectivity, and a phase-shifting property of the isolated areas is substantially different from that of a remainder of the area of the unit cell.
Dependencies are inferred from the claim text.