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US6787789B2
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Method of measuring aberration of a projection system of a lithographic apparatus, device manufacturing method, and device manufactured thereby
Assignee: ASML Netherlands BV
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Filing: 2002-08-22
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Granted: 2004-09-07
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Expires: 2022-08-22
Abstract
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.
Inventors
- 👤 Hans Van Der Laan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 06:38
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70483; G03F7/70591; G03F7/706; H; H10; H10P; H10P76/00
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
146 words
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.
Claim 2
Independent Claim
146 words
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.
Claim 3
Dependent Claim
47 words
The method of determining aberration of a projection system according to claim 1 , wherein each unit cell has the shape of a hexagon and includes six isolated areas, each isolated area being positioned at or near a corresponding one of the six corners of the hexagon.
Claim 4
Dependent Claim
34 words
The method of determining aberration of a projection system according to claim 1 , wherein each unit cell has a shape selected from the group consisting of a triangle, a quadrangle, and a hexagon.
Claim 5
Dependent Claim
63 words
The method of determining aberration of a projection system according to claim 1 , wherein the at least one parameter includes a difference between a value of a characteristic of an image of an isolated area of a unit cell and a value of the same characteristic of an image of each of at least one other isolated area of the unit cell.
Claim 6
Dependent Claim
59 words
The method of determining aberration of a projection system according to claim 4 , wherein the characteristic is selected from the group consisting of peak intensity, spatially integrated intensity, spatial intensity distribution, a shape of a cross section of the image of the isolated area, and a size of a cross section of the image of the isolated area.
Claim 7
Dependent Claim
41 words
The method of determining aberration of a projection system according to claim 1 , wherein said directly measuring is performed using radiation detection means comprising a plurality of radiation apertures, wherein the radiation apertures are arrayed in a two-dimensional matrix pattern.
Claim 8
Dependent Claim
29 words
The method of determining aberration of a projection system according to claim 1 , wherein said plurality of different illumination settings includes a plurality of different numerical aperture settings.
Claim 9
Dependent Claim
47 words
The method of determining aberration of a projection system according to claim 1 , wherein said plurality of different illumination settings includes a plurality of different settings of at least one of the outer and the inner radial extent of the intensity distribution of the projection beam.
Claim 10
Dependent Claim
42 words
The method of determining aberration of a projection system according to claim 1 , wherein said plurality of different illumination settings includes a plurality of different illumination modes selected from the group consisting of disc-shaped, annular, quadrupolar, dipolar and soft-multipolar illumination mode.
Claim 11
Dependent Claim
52 words
The method of determining aberration of a projection system according to claim 1 , wherein said at least one parameter includes at least one of (1) a position of best focus of the aerial image of the test pattern and (2) a lateral position of the aerial image of the test pattern.
Claim 12
Dependent Claim
45 words
The method of determining aberration of a projection system according to claim 1 , further comprising calculating a variation of at least one of the at least one parameter as a function of a change in at least one of the at least one coefficient.
Claim 13
Dependent Claim
39 words
The method of determining aberration of a projection system according to claim 1 , wherein said calculating at least one coefficient includes using at least one of multiple regression and a least-square fit of a set of simultaneous equations.
Claim 14
Dependent Claim
24 words
The method of determining aberration of a projection system according to claim 1 , wherein the at least one coefficient is a Zernike coefficient.
Claim 15
Dependent Claim
34 words
The method of determining aberration of a projection system according to claim 1 , wherein the test pattern further includes at least one supplementary test pattern having a structure different than the two-dimensional lattice.
Claim 16
Dependent Claim
54 words
The method of determining aberration of a projection system according to claim 14 , wherein the at least one supplementary test pattern is selected from the group of two-dimensional pattern structures consisting of (1) a segment of a grating with periodic lines and spaces and (2) a repeating structure of parallel, line-shaped isolated areas.
Claim 17
Independent Claim
217 words
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.
Claim 18
Independent Claim
217 words
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.
Claim 19
Dependent Claim
31 words
The method of manufacturing a device according to claim 16 , wherein each unit cell has a shape selected from the group consisting of a triangle, a quadrangle, and a hexagon.
Claim 20
Dependent Claim
38 words
The method of manufacturing a device according to claim 16 , wherein said directly measuring is performed using radiation detection means comprising a plurality of radiation apertures, wherein the radiation apertures are arrayed in a two-dimensional matrix pattern.
Claim 21
Dependent Claim
12 words
A device manufactured in accordance with the method of claim 16 .
Claim 22
Independent Claim
140 words
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.
Claim 23
Independent Claim
140 words
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.
Claim 24
Dependent Claim
34 words
The method of determining aberration of a projection system according to claim 20 , wherein each unit cell has a shape selected from the group consisting of a triangle, a quadrangle, and a hexagon.
Claim 25
Dependent Claim
41 words
The method of determining aberration of a projection system according to claim 20 , wherein said directly measuring is performed using radiation detection means comprising a plurality of radiation apertures, wherein the radiation apertures are arrayed in a two-dimensional matrix pattern.
References Cited (Backward Citations)
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