Lithographic apparatus and method for optimizing illumination using a photolithographic simulation

Claim 3

The method of claim 1 , wherein the maximum or minimum value is within a selected range of variation of the lithographic response.

Claim 4

The method of claim 2 , wherein the lithographic response is CD variation and the range is about +/−5%.

Claim 5

The method of claim 1 , wherein the lithographic response is CD variation, CD uniformity, MEEF, depth of focus, exposure latitude or E1:1.

Claim 6

The method of claim 1 , wherein the calculating includes calculating the metric that represents a variation of a lithographic response of the printed pattern over a plurality of process variation ranges, and wherein the metric is a quadratic sum of CD variations that are each induced by one of the plurality of process ranges.

Claim 7

The method of claim 5 , wherein the plurality of process ranges include a focus range, a patterning device error range and a dose range.

Claim 8

The method of claim 1 , wherein the varying and the calculating are done by computer simulation.

Claim 9

The method of claim 1 , wherein the varying and the calculating further comprises using a parameter representing a polarization state of radiation within an illumination system of the lithographic apparatus.

Claim 10

The method of claim 1 , wherein the determining includes determining an intermediate focus variation range by varying an initial focus variation range using a calibrated model until the calculated image of the pattern printed on the substrate is within predetermined specification, the focus variation range being applied during exposure of the substrate by the lithographic apparatus; wherein the calculating includes calculating a metric that represents a variation of a lithographic response of the printed pattern over a process range, where the pattern would be imaged with the intermediate illumination arrangement and patterning device parameters over the process range and the intermediate focus variation range, and wherein the varying and calculating include, depending on a result of the metric, iteratively (a) varying the initial patterning device and illumination arrangement parameters and the initial focus variation range and (b) calculating the metric until a substantially maximum or minimum value of the lithographic response is obtained.

Claim 11

The method of claim 1 , wherein the predetermined specification includes a variation of a critical dimension of the pattern in a range of about +/−5%.

Claim 12

The method of claim 1 , wherein the intermediate and initial illumination arrangement parameters include a radius, an opening angle, a radial width or an intensity of an illumination arrangement in a pupil plane of an illumination system of the lithographic apparatus.

Claim 13

The method of claim 1 , wherein the intermediate and initial patterning device parameters include a critical dimension of the pattern, a dimension between two adjacent features of the pattern or a critical dimension of an optical proximity correction feature arranged in the pattern.

Claim 14

A lithographic apparatus, comprising an illumination system configured to condition a beam of radiation; a substrate table configured to hold a substrate; a projection system configured to project a beam of radiation patterned by a patterning device onto a surface of the substrate; and a processor to perform a method of configuring a transfer of an image of a patterning device pattern onto the substrate, the method comprising: determining an intermediate illumination arrangement parameter and an intermediate patterning device parameter by varying an initial illumination arrangement parameter and an initial patterning device parameter using a calibrated model until the calculated image of the pattern on the substrate is within predetermined specification; calculating a metric that represents a variation of a lithographic response of the printed pattern over a process range, where the pattern would be imaged with the intermediate illumination arrangement and patterning device parameters over a process range, and depending on a result of the metric, iteratively (a) varying the initial patterning device and illumination arrangement parameters and (b) calculating the metric until a substantially maximum or minimum value of the lithographic response is obtained.

Claim 15

A lithographic apparatus, comprising an illumination system configured to condition a beam of radiation; a substrate table configured to hold a substrate; a projection system configured to project a beam of radiation patterned by a patterning device onto a surface of the substrate; and a processor to perform a method of configuring a transfer of an image of a patterning device pattern onto the substrate, the method comprising: determining an intermediate illumination arrangement parameter and an intermediate patterning device parameter by varying an initial illumination arrangement parameter and an initial patterning device parameter using a calibrated model until the calculated image of the pattern on the substrate is within predetermined specification; calculating a metric that represents a variation of a lithographic response of the printed pattern over a process range, where the pattern would be imaged with the intermediate illumination arrangement and patterning device parameters over a process range, and depending on a result of the metric, iteratively (a) varying the initial patterning device and illumination arrangement parameters and (b) calculating the metric until a substantially maximum or minimum value of the lithographic response is obtained.

Claim 16

The lithographic apparatus of claim 13 , wherein if the result of the metric is within a threshold, the apparatus is configured to adjust a setting of the illumination system in accordance with the intermediate illumination arrangement parameter.

Claim 17

The lithographic apparatus of claim 13 , further comprising a selectably variable beam controller that is adapted to modify a cross-sectional intensity distribution in the beam of radiation exiting the illumination system in accordance with the adjusted illumination arrangement parameter.

Claim 18

The apparatus of claim 15 , wherein the lithographic response is CD variation and the threshold is a range of about +/−5%.

Claim 19

The apparatus of claim 13 , wherein the lithographic response is CD variation, CD uniformity, MEEF, depth of focus, exposure latitude or E1:1.

Claim 20

The apparatus of claim 13 , wherein the varying and calculating includes using a parameter representing a polarization state of radiation within the illumination system, and wherein the apparatus is configured to adjust the polarization state of the illumination system based on the result of the metric.

Claim 21

The apparatus of claim 13 , wherein the varying and calculating includes using a parameter representing a focus variation that is applied during exposure of the substrate by the lithographic apparatus, and wherein the apparatus is configured to adjust the focus variation based on the result of the metric.

Claim 22

A computer product, embodied in a computer-readable medium, having machine executable instructions, the instructions being executable by a machine to perform a method of configuring a transfer of an image of a patterning device pattern onto a substrate with a lithographic apparatus, the method comprising: determining an intermediate illumination arrangement parameter and an intermediate patterning device parameter by varying an initial illumination arrangement parameter and an initial patterning device parameter using a calibrated model until the calculated image of the pattern printed on the substrate is within predetermined specification; calculating a metric that represents a variation of a lithographic response of the printed pattern over a process range, where the pattern would be imaged with the intermediate illumination arrangement and patterning device parameters over the process range, and depending on a result of the metric, iteratively (a) varying the initial patterning device and illumination arrangement parameters and (b) calculating the metric until a substantially maximum or minimum value of the lithographic response is obtained.

Claim 23

A computer product, embodied in a computer-readable medium, having machine executable instructions, the instructions being executable by a machine to perform a method of configuring a transfer of an image of a patterning device pattern onto a substrate with a lithographic apparatus, the method comprising: determining an intermediate illumination arrangement parameter and an intermediate patterning device parameter by varying an initial illumination arrangement parameter and an initial patterning device parameter using a calibrated model until the calculated image of the pattern printed on the substrate is within predetermined specification; calculating a metric that represents a variation of a lithographic response of the printed pattern over a process range, where the pattern would be imaged with the intermediate illumination arrangement and patterning device parameters over the process range, and depending on a result of the metric, iteratively (a) varying the initial patterning device and illumination arrangement parameters and (b) calculating the metric until a substantially maximum or minimum value of the lithographic response is obtained.

Claim 24

The computer product of claim 20 , wherein the maximum or minimum value is within a selected range of variation of the lithographic response.

Claim 25

The computer product of claim 21 , wherein the lithographic response is CD variation and the range is about +/−5%.

Claim 26

The computer product of claim 20 , wherein the lithographic response is CD variation, CD uniformity, MEEF, depth of focus, exposure latitude or E1:1.

Claim 27

The computer product of claim 20 , wherein the calculating includes calculating the metric that represents a variation of a lithographic response of the printed pattern over a plurality of process variation ranges, and wherein the metric is a quadratic sum of CD variations that are each induced by one of the plurality of process ranges.

Claim 28

The computer product of claim 24 , wherein the plurality of process ranges include a focus range, a patterning device error range and a dose range.

Claim 29

The computer product of claim 20 , wherein the varying and the calculating are done by computer simulation.

Claim 30

The computer product of claim 20 , wherein the determining includes determining an intermediate polarization state of radiation within an illumination system of the lithographic apparatus by varying an initial polarization state, wherein the calculating includes calculating a metric that represents a variation of a lithographic response of the printed pattern over a process range, where the pattern would be imaged with the intermediate illumination arrangement and patterning device parameters over the process range and the intermediate polarization state, and wherein the varying and calculating include, depending on a result of the metric, iteratively (a) varying the initial patterning device and illumination arrangement parameters and the initial polarization state and (b) calculating the metric until a substantially maximum or minimum value of the lithographic response is obtained.

Claim 31

The computer product of claim 20 , the determining includes determining an intermediate focus variation range by varying an initial focus variation range using a calibrated model until the calculated image of the pattern could be substantially printed on the substrate is within predetermined specification, the focus variation range being applied during exposure of the substrate by the lithographic apparatus; wherein the calculating includes calculating a metric that represents a variation of a lithographic response of the printed pattern over a process range, where the pattern would be imaged with the intermediate illumination arrangement and patterning device parameters over the process range and the intermediate focus variation range, and wherein the varying and calculating include, depending on a result of the metric, iteratively (a) varying the initial patterning device and illumination arrangement parameters and the initial focus variation range and (b) calculating the metric until a substantially maximum or minimum value of the lithographic response is obtained.

Claim 34

The method of claim 29 , wherein the plurality of initial intermediate parameters include an illumination arrangement parameter, an intermediate patterning device parameter, and a polarization state of radiation within an illumination system of the lithographic apparatus and/or a focus variation range, and/or a projection system parameter.