CN1570585A - Field measurement method for aberration of imaging optical system - Google Patents
Field measurement method for aberration of imaging optical system Download PDFInfo
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Abstract
This invention relates to an on-site method to measure spherical aberration, coma aberration and at least one optical aberration of astigmatism of the photo-etching machine image-forming optical system through measuring the system image-forming aberration. According to the aberration datum measured in conditions of different data aperture and partly coherent factor, we can figure out spherical aberration, coma aberration and at least one optical aberration of astigmatism. The measuring precision can be increased through changing the light intensity distribution of the said image-forming optical system.
Description
Technical field:
The present invention relates to the on-site measurement method of imaging optical system aberration, particularly relate to the on-site measurement method of the aberration of imaging optical system of photoetching.
Background technology:
In the prior art, with the pattern that is formed on the various masks, with exposure light illumination, the middle exposure device that aforementioned pattern is copied on the substrates such as the wafer that is coated with photoresist, glass substrate via imaging optical system is known.
In recent years, semiconductor element is more and more highly integrated, requires the further miniaturization of its circuit patterns.Along with diminishing of lithographic feature size, the especially use of off-axis illumination and phase shifting mask, aberration becomes more and more outstanding to the influence of photoetching quality.Therefore the in-site measurement technology of litho machine projection imaging optical system is indispensable.
The measurement of imaging optical system aberration is carried out usually as follows.Below be example with the projection objective system.That is, aberration measurement is placed on the object plane with mask, images on the last aforesaid base plate of the picture of projection objective system, imaging is developed forming regulation pattern on the mask.Utilize scanning electron microscope (SEM) that the picture that has developed is measured then, obtain the aberration of aforementioned projection objective lens optical system according to measurement result.(formerly technology 1,16.Peter Dirksen, Casper A.Juffermans, Ruud J.Pellens, Mireille Maenhoudt, PeterDebisschop. " Novel aberration monitor for optical lithography. " Proc.SPIE 1999,3679,77-86.)
But in the method for aforementioned techniques, because the photoresist crawling is even, the inhomogeneous treatment process error that waits of developing makes the measuring accuracy of aforementioned aberration fully not guarantee.And before utilizing SEM to observe, need carry out pre-treatment to silicon chip, as developing process, therefore the mensuration for aberration needs long time.
For fear of these problems, people have proposed the method for utilizing transmission-type image-position sensor (TIS) that aforementioned projection objective wave aberration is measured.(formerly technology 2, Van der Laan, Hans, Dierichs, Marcel, van Greevenbroek, Henk, McCoo, Elaine, Stoffels, Fred, Pongers, Richard, Willekers, Rob. " Aerial imagemeasurement methods for fast aberration set-up and illumination pupil verification. " Proc.SPIE 2001,4346,394-407.) TIS is made of two kinds of detectors: isolated line and a square hole of a cover submicron order, independently photodiode is all placed in isolated line and square hole below.Wherein isolated line comprises two kinds of the isolated lines of the isolated line of directions X and Y direction, and the isolated line of different directions is respectively applied for the image space of measuring the different directions lines.Square hole is used for the light-intensity variation of compensating illumination light source.TIS can measured X direction lines image space (Y, Zy), Y direction lines image space (Y, Zy).
Aberration mensuration is placed on the mask platform with binary mask, has shape to be similar to the mark of TIS on this mask.The intensive lines that the mark of measuring the coma employing is are isolated lines and measure the spherical aberration employing.Make on the TIS scanning mask mark through the projection objective imaging by the travelling workpiece platform, (zx zy), and obtains imaging offset (Δ X, Δ Y, Δ Zx, Δ Zy) with ideal position after relatively for x, y can to obtain the image space of mark.At the image space of measuring each mark on the mask under different NA and the σ, obtain the imaging offset at diverse location place in the visual field under the different lighting conditions, obtain corresponding Z ernike coefficient Z2, Z3, Z4, Z5, Z7 after utilizing mathematical model to calculate then, Z8, Z14, Z15, Z9, Z16, Z12, Z21.But along with the development of photoetching technique, the requirement of aberration measurement precision is also improved constantly, this measuring technique can not satisfy requirement on the precision just gradually.
Summary of the invention:
The present invention does at the problem of above-mentioned prior art existence, the object of the present invention is to provide the method for at least a aberration in a kind of high-precision in-site measurement imaging optical system spherical aberration, coma, the astigmatism.
The invention provides a kind of on-site measurement method of imaging optical system aberration, the employed system of described method comprises: the light source that produces projected light beam; Be used to adjust the light distribution of the light beam that described light source sends and the illuminator of partial coherence factor; The imaging optical system that mask pattern imaging and its numerical aperture can be able to be regulated; Can carry described mask and pinpoint mask platform; Can carry silicon chip and pinpoint work stage; Be installed in the image-position sensor of the measurement markers image space on the described work stage, said method comprising the steps of: the sensitivity matrix of demarcating described imaging optical system; The light beam that described light source is sent shines in described mask after adjusting through described illuminator; Described mask optionally sees through a part of light; The described imaging optical system of light process that sees through like this is with the pattern imaging on the mask; Near with the pattern image space on the described image-position sensor measurement mask the three-dimensional light distribution of aerial image can obtain image space axially drift and image space lateral drift; Numerical aperture by changing described imaging optical system and by adjusting described illuminator to change the partial coherence factor of light beam, measure the described image space drift value of many groups, then use described sensitivity matrix to calculate at least a aberration in spherical aberration, coma, the astigmatism, its characteristics are, improve the precision of described measurement by the light distribution that changes described imaging optical system emergent pupil face place.
The on-site measurement method of described imaging optical system aberration, be preferably, by using phase shifting mask as described mask, or the mask of mark that comprises the different characteristic size and shape by use is as described mask, or to the light of described imaging optical system emergent pupil face carry out pupil filtering with the light intensity that changes different space frequency light or/carry out the change of the light distribution at described imaging optical system emergent pupil face place with at least a method in three kinds of methods mutually.
The on-site measurement method of described imaging optical system aberration is preferably, and described phase shifting mask is any one in attenuated phase-shifting mask, alternating phase-shift mask, chromium-less phase shifting mask, the edge enhancement mode phase shifting mask.
The on-site measurement method of described imaging optical system aberration is preferably, and comprises that by use the mask of the mark of different characteristic size and shape carries out the change of the light distribution at described imaging optical system emergent pupil face place as described mask.
The on-site measurement method of described imaging optical system aberration is preferably, and described characteristic dimension comprises size, the spacing of each ingredient in the mark.
The on-site measurement method of described imaging optical system aberration is preferably, and described light source is ultraviolet, deep ultraviolet, extreme ultraviolet light sources such as mercury lamp or excimer laser.
By changing over the light distribution at image optical system emergent pupil face place, the sensitivity that can improve sensitivity matrix, thereby the measuring accuracy of raising aberration.
Description of drawings:
Fig. 1 is the structural representation according to the exposure device of the embodiment of the invention.
Fig. 2 a is the synoptic diagram of the used mark of invention.
Fig. 2 b is the sectional view of Wx along the planimetric map on XZ plane and Wy along the YZ plane among Fig. 2 a.
Fig. 3 a and Fig. 3 b are for being zero at other Zernike coefficient, under the big or small certain condition of Z7 and NA, compared use phase shifting mask (Fig. 3 b) and do not use phase shifting mask (under Fig. 3 situation a), the internal and external parts coherence factor that draws by simulation software and the graph of a relation of image space transversal displacement.
Fig. 4 is for being zero at other Zernike coefficient, under the certain condition of Z7, numerical aperture, outer partial coherence factor size, and the graph of a relation of marker characteristic size, interior partial coherence factor and the image space transversal displacement that draws by simulation software.
Fig. 5 a and Fig. 5 b are for being zero at other Zernike coefficient, under the big or small certain condition of Z7 and NA, compared use pupil filtering (Fig. 5 b) and do not use pupil filtering (under Fig. 5 situation a), the internal and external parts coherence factor that draws by simulation software and the graph of a relation of image space transversal displacement.
Embodiment:
The system that is carried out to image optical system aberration in-site measurement comprises light source, adjust the illuminator of the light that described light source sends, with the mask platform of the adjusted light-struck mask of described illuminator, the described mask of placement, be used for imaging optical system, the work stage of described mask imaging and be placed in transmission-type image-position sensor on the described work stage.
After the light that described light source (mercury lamp or excimer laser) sends directly enters described illuminator, or illuminator as described in entering after the process certain way adjustment (as expanding bundle).Have in the described illuminator and can change the illuminating bundle light distribution, thereby adjust the element of internal and external parts coherence factor.Usually also have other a large amount of elements such as integrating rod etc. in the described illuminator.The light of illumination on described mask has the spatial frequency distribution and the more satisfactory homogeneity of expection like this.
Light beam is through being radiated on the described mask after the described illuminator.Described mask is positioned on the described mask platform.Described mask optionally sees through a part of light, and this part light is through focusing on the target location on the silicon chip behind the described imaging optical system.Described silicon slice placed places on the work stage.Under the location of interferometer, described work stage can accurately move.Simultaneously by some alignment methods can so that described work stage and described mask platform with the optical axis alignment of imaging optical system.Like this, the pattern on the described mask just can accurately be replicated in the described target area on the described silicon chip.In addition, described transmission-type image-position sensor is installed on the described work stage, is used to measure the position of similar label space picture on the described mask.
Embodiment 1
Fig. 1 is the structural representation according to the exposure device of the embodiment of the invention.As shown in Figure 1, the laser that laser instrument LS (excimer laser) sends directly enters illuminator IL, or through entering illuminator after the certain way adjustment (as expanding bundle).Have among the illuminator IL and can change the illuminating bundle light distribution, thereby adjust the element of internal and external parts coherence factor.Usually also have other a large amount of elements such as integrating rod etc. in the illuminator.The light of illumination on mask R has the spatial frequency distribution and the more satisfactory homogeneity of expection like this.
On the mask R of light beam through shining after the illuminator.Mask R is positioned on the mask platform RS.Mask R optionally sees through a part of light, and this part light focuses on the target location on the silicon chip W after having the projection objective PL that adjusts the numerical aperture function.Silicon chip W is positioned on the work stage WS.Under the location of interferometer IF, work stage WS can move accurately.Simultaneously by some alignment methods can so that work stage WS and mask platform RS with the optical axis alignment of imaging optical system.Like this, the pattern on the mask R just can be replicated in the target area of W on the silicon chip accurately.In addition, transmission-type image-position sensor TIS is installed on the work stage WS, it can be used for measuring the position of similar label space picture on the mask, about further describing referring to United States Patent (USP) 4,540,277 of TIS.
The projection objective aberration can be described as the wave aberration on the object lens emergent pupil face, i.e. actual wavefront departing from respect to desirable wavefront.Wave aberration can be decomposed into the polynomial form of Zernike, sees (1) formula.ρ and θ are normalized polar coordinates on the emergent pupil face in the formula.Wherein, Z2 and Z3 item characterize the inclination of image planes.The Z4 item characterizes defocusing amount, and Z5 and Z6 characterize three rank astigmatisms of different directions.Other items that contain cos θ, sin θ correspond respectively to three rank, Pyatyi and the every senior coma on meridian and the sagitta of arc direction.Other items that do not contain θ are corresponding to axial three rank, Pyatyi and high-order spherical aberration, and the aberration form of concrete various Zernike coefficient correspondences sees the following form:
| Aberration (Aberration) | Low order Zernikes | High-order Zernikes | ||
| ?m | Title (Name) | Function (Function) | Item (Term) | Item (Term) |
| ?0 | Spherical aberration (Spherical) | ??6r 4-6r 2+1 | ?Z9 | Z16，Z25，Z36，Z37 |
| ?1 | X-coma (X-Coma) | ??(3r 3-2r)cos(θ) | ?Z7 | Z14，Z23，Z34 |
| ?1 | Y-coma (Y-Coma) | ??(3r 3-2r)sin(θ) | ?Z8 | Z15，Z24，Z35 |
| ?2 | Astigmatism (Astigmatism) | ??r 2cos(2θ) | ?Z5 | Z12，Z21，Z32 |
| ?2 | 45 ° of astigmatisms (45 ° of Astigmatism) | ??r 2sin(2θ) | ?Z6 | Z13，Z22，Z33 |
| ?3 | X-three ripples are poor | ??r 2cos(2θ) | ?Z10 | Z19，Z30 |
| ?3 | Y-three ripples are poor | ??r 2sin(2θ) | ?Z11 | Z20，Z31 |
w(ρ，θ)???????????????+Z
12·(4ρ
4-3ρ
2)cos2θ
＝Z
1???????????????????+Z
13·(4ρ
4-3ρ
2)sin2θ
+Z
2·ρcosθ????????????????????????+Z
14·(10ρ
5-12ρ
3+3ρ)cosθ
+Z
3·ρsinθ????????????????????????+Z
15·(10ρ
5-12ρ
3+3ρ)sinθ
+Z
4·(2ρ
2-1)?????????+Z
16·(20ρ
6-30ρ
4+12ρ
2-1)
+Z
5·ρ
2cos2θ??????????????????+Z
17·ρ
4cos4θ
+Z
6·ρ
2sin2θ??????????????????+Z
18·ρ
4sin4θ
+Z
7·(3ρ
3-2ρ)cosθ??????+Z
19·(5ρ
5-4ρ
3)cos3θ
+Z
8·(3ρ
3-2ρ)sinθ??????+Z
20·(5ρ
5-4ρ
3)sin3θ
+Z
9·(6ρ
4-6ρ
2+1)???+Z
21·(15ρ
6-20ρ
4+6ρ
2)cos2θ
+Z
10·ρ
3cosθ???????????????????+Z
22·(15ρ
6-20ρ
4+6ρ
2)sin2θ
+Z
11·ρ
3sinθ???????????????????+Λ????????????????????????????????(1)
The influence to imaging of departing from of wavefront shows as actual imaging departing from and be out of shape for desirable Gaussian image.Under the telecentric light situation, can define two class aberrations: idol difference and strange aberration according to a kind of like this form of expression.The idol difference is meant that it is symmetrical that wavefront departs from respect to optical axis, for example spherical aberration, astigmatism, and it makes paraxial rays and marginal ray that different picture points be arranged, image space has just produced axial drift like this.On the contrary, it is asymmetric that the wavefront of strange aberration departs from respect to optical axis, coma for example, and it makes image space generation lateral excursion.Change numerical aperture of objective NA and partial coherence factor σ, then the axial drift value of object lens imaging position and lateral drift amount can change, and its variable quantity is the function of numerical aperture NA and partial coherence factor σ.
The present invention detects axial drift value of image space and image space lateral drift amount under different numerical aperture NA and the different piece coherence factor σ by the transmission image-position sensor, calculates corresponding Z ernike coefficient then.Promptly, obtain imaging offset (Δ X, the Δ Y at diverse location place in the visual field under the different lighting conditions in the aerial image position of measuring each mark on the mask under different NA and the σ, Δ Z), obtain the Zernike coefficient Z2 at diverse location place in the visual field after utilizing mathematical model to analyze then, Z3, Z7, Z8, Z14, Z15, Z4, Z5, Z9, Z16, Z12, Z21.
The meridian coma is the directions X skew that the coma of directions X can cause image space, and side-play amount is except outside the Pass having with the coma size, and is also relevant with partial coherence factor and numerical aperture.Side-play amount can be expressed as
X (NA wherein, σ) be the detected image space directions X of transmission image-position sensor drift value under given numerical aperture and partial coherence factor, Z2, Z7, Z14 is the Zernike coefficient that will calculate, represent respectively wavetilt, X to three rank comas, X to the Pyatyi coma.For different NA and σ, calculate Δ X respectively to Z2, Z7, the partial derivative of Z14 can obtain following matrix equation group:
System of equations (3) can be abbreviated as
Wherein M is that the detected image space X of transmission image-position sensor is to drift value under different N A, σ, and S is a sensitivity matrix, and Z is the Zernike coefficient vector that will find the solution.Like this, the image space X that measures under different N A and the σ situation by the transmission image-position sensor can calculate corresponding to X to the Zernike of coma coefficient (Z2, Z7, Z14) to drift value.In like manner, the image space Y that measures under different N A and the σ situation by the transmission image-position sensor can calculate corresponding to Y to the Zernike of coma coefficient (Z3, Z8, Z15) to drift value.The different directions lines image space Z that measures under different N A and the σ situation by the transmission image-position sensor can calculate the Zernike coefficient (Z4, Z9, Z16) corresponding to spherical aberration to the mean value (Δ Zs=(Δ Zx+ Δ Zy)/2) of drift value.Different directions lines image space Z to drift value difference (Δ Za=(Δ Zx+ Δ Zy)/2) can calculate Zernike coefficient (Z5, Z12, Z21) corresponding to astigmatism.
Sensitivity matrix S can use lithography simulation software to calculate.As to get Zernike coefficient Z7 be that 1nm and other Zernike coefficients are zero, utilizes the lithography simulation computed in software to go out the X of this moment, then can be with the X of this moment as the partial derivative of X to Z7, and it is defined as sensitivity s, that is:
Therefore the degree of accuracy of sensitivity matrix and the height of sensitivity are the key factors of the measuring accuracy of every Zernike coefficient.
Fig. 2 a is for adopting the synoptic diagram of mark in the invention.Among Fig. 2 a Wx be used to measure the corresponding largest light intensity of Y direction lines position (X, Zx), Wy be used for the corresponding largest light intensity of measured X direction lines position (Y, Zy).The sectional view of Wx along the sectional view on XZ plane and Wy along the YZ plane is all shown in Fig. 2 b.Among Fig. 2 b, 1 is mask substrate, is generally quartzy.2 is suprabasil lighttight coating, is generally chromium.3 for mask placement environment, is generally air.F is the characteristic dimension of mark.Adjacent two printing opacity position thickness differences are d, d=λ/2 Δ n.Wherein λ is an exposure wavelength, and Δ n is 1 and 3 refringence.
After using above-mentioned mark, the imaging offset that obtains under the NA situation identical with σ (Δ X, Δ Y, Δ Zs, Δ Za) can change.When using phase shifting mask, its effect is that 0 rank diffraction light is weakened, and other level time diffraction light strengthens, and that is to say that the light distribution meeting on the pupil plane changes.When object lens had aberration, the optical path difference of each point was inequality on the pupil plane.Therefore, imaging offset will change.
When using phase shifting mask, its effect is that 0 rank diffraction light is weakened, and other level time diffraction light strengthens.Appropriate use phase shifting mask can make the light distribution on the pupil plane very concentrated.Can strengthen the light intensity of different space frequency this moment by changing different lighting conditions.For Z7, Z8, Z9, Z12 in the Zernike coefficient, the imaging offset that is incident on the light of the image space deviation of light at the edge of pupil plane and center differs maximum.For Z14, Z15, Z16, Z21 in the Zernike coefficient is that the image space deviation that is incident near the image space deviation of the light at pupil plane edge and the light of center differs maximum.Therefore use phase shifting mask, will increase the variation range of image space deviation.
Fig. 3 is zero at other Zernike coefficient, under Z7 and the certain condition of NA size, has compared use phase shifting mask (Fig. 3 b) and do not used phase shifting mask that (under Fig. 3 situation a), the Δ X that is drawn by simulation software is with the situation of internal and external parts coherence factor variation.As seen from Figure 3, use phase shifting mask to make under Z7 one stable condition, the variation range of Δ X increases under the different piece coherence factor condition.Similarly, when partial coherence factor one timing, the use of phase shifting mask also makes the variation range of Δ X increase.By (4) formula as can be seen, the variation range increase of Δ X makes the variation range of sensitivity S z7 increase.
For all other Zernike coefficients, use phase shifting mask equally also to make the corresponding change of sensitivity scope of this Zernike coefficient increase.This that is to say that after having used phase shifting mask, every sensitivity increases with the variation range of NA and σ.As the mark of the formation of the intensive lines of 250nm, adopt phase shifting mask after, the change of sensitivity scope will increase by 21.9%.Can predict suitable selection NA and σ, the sensitivity that can improve sensitivity matrix S.
Owing to use phase shifting mask can increase contrast, that is to say that largest light intensity and minimum intensity of light difference will increase, so under the certain situation of TIS measurement light intensity precision and work stage interferometer measurement precision, the measurement of imaging offset will be more accurate.
Use phase shifting mask can improve the sensitivity of sensitivity matrix and the measuring accuracy of imaging offset simultaneously.Use phase shifting mask can improve measuring accuracy tens percent magnitudes of aberration.
Embodiment 2
Except changing NA and σ, equally also can change the spatial frequency distribution of diffraction light by the characteristic dimension that changes mark, promptly change the light distribution at described imaging optical system emergent pupil face place, thereby sensitivity matrix is changed.Fig. 4 has shown that at other Zernike coefficient be zero, under Z7, numerical aperture, the big or small certain condition of outer partial coherence factor, and the relation of marker characteristic size, interior partial coherence factor and imaging offset Δ X.As seen from Figure 4, under the different interior partial coherence factor conditions, use the mark of different characteristic size that the variation range of Δ X will be increased.Similarly, certain or internal and external parts coherence factor one regularly uses the mark of different characteristic size that the variation range of Δ X will be increased when interior partial coherence factor and numerical aperture.By (4) formula as can be seen, the variation range increase of Δ X makes the variation range of sensitivity S z7 increase.
For all other Zernike coefficients, use the mark of different characteristic size equally also to make the corresponding change of sensitivity scope of this Zernike coefficient increase.This that is to say that behind the mark that has used the different characteristic size, every sensitivity increases with the variation range of NA and σ.
Therefore the characteristic dimension of making mark on mask simultaneously will make sensitivity matrix more sensitive, thereby improve measuring accuracy.This moment sensitivity matrix become NA, σ and characteristic dimension f function S (NA, σ, f).
Embodiment 3
Except changing NA and σ, by pupil filtering set can be suitable selection from the light of emergent pupil outgoing, promptly change the light distribution at described imaging optical system emergent pupil face place, thereby change the spatial frequency distribution of light, thereby sensitivity matrix is changed.Set the emergent ray that to select pupil to take up an official post anticipate the position owing to change pupil filtering, so this method makes that the variable quantity of imaging offset is bigger.
Fig. 5 is zero at other Zernike coefficient, under the certain condition of Z7, numerical aperture size, compared use pupil filtering (Fig. 5 b) and do not use pupil filtering (under Fig. 5 situation a), the relation of partial coherence factor and imaging offset Δ X.As seen from Figure 5, under the big or small certain condition of numerical aperture, use pupil filtering that the variation range of Δ X will be increased.Similarly, interior partial coherence factor or outer partial coherence factor one regularly use the pupil filtering setting that the variation range of Δ X will be increased.By (4) formula as can be seen, the variation range increase of Δ X makes the variation range of sensitivity S z7 increase.
For all other Zernike coefficients, use different pupil filterings to set and equally also make the corresponding change of sensitivity scope of this Zernike coefficient increase.This that is to say that after having used different pupil filterings to set, every sensitivity increases with the scope that NA and σ change.
Therefore change pupil filtering and set, will make sensitivity matrix more sensitive, thereby improve measuring accuracy.
In the above-described embodiment, the light source that uses is ultraviolets such as mercury lamp or excimer laser, deep ultraviolet, extreme ultraviolet light source.The imaging optical system that uses is projection objective, but also can measure equally for other imaging optical system.In addition, use mask, the pupil filtering method to set up of phase shifting mask, use various features size can use use also capable of being combined separately.
Claims (5)
1, a kind of on-site measurement method of imaging optical system aberration, the employed system of described method comprises: the light source that produces projected light beam; Be used to adjust the light distribution of the light beam that described light source sends and the illuminator of partial coherence factor; The imaging optical system that mask pattern imaging and its numerical aperture can be able to be regulated; Can carry described mask and pinpoint mask platform; Can carry silicon chip and pinpoint work stage; Be installed in the image-position sensor of the measurement markers image space on the described work stage,
Said method comprising the steps of: the sensitivity matrix of demarcating described imaging optical system; The light beam that described light source is sent shines in described mask after adjusting through described illuminator; Described mask optionally sees through a part of light; The described imaging optical system of light process that sees through like this is with the pattern imaging on the mask; Near with the pattern image space on the described image-position sensor measurement mask the three-dimensional light distribution of aerial image can obtain imaging offset; Numerical aperture by changing described imaging optical system and/or by adjusting described illuminator to change partial coherence factor, measure the described imaging offset of many groups, then use described sensitivity matrix to calculate at least a aberration in spherical aberration, coma, the astigmatism
It is characterized in that, improve the precision of described measurement by the light distribution that changes described imaging optical system emergent pupil face place.
2, according to the on-site measurement method of the described imaging optical system aberration of claim 1, it is characterized in that, by using phase shifting mask as described mask, or the mask of mark that comprises the different characteristic size and shape by use is as described mask, or to the light of described imaging optical system emergent pupil face carry out pupil filtering with the light intensity that changes different space frequency light or/with mutually, at least a method in three kinds of methods is used for carrying out the change of described imaging optical system emergent pupil face place's light distribution.
According to the on-site measurement method of the described imaging optical system aberration of claim 2, it is characterized in that 3, described phase shifting mask is any one in attenuated phase-shifting mask, alternating phase-shift mask, chromium-less phase shifting mask, the edge enhancement mode phase shifting mask.
According to the on-site measurement method of the described imaging optical system aberration of claim 2, it is characterized in that 4, described characteristic dimension comprises size, the spacing of each ingredient in the mark.
According to the on-site measurement method of each described imaging optical system aberration among the claim 1-4, it is characterized in that 5, described light source is ultraviolet, deep ultraviolet, extreme ultraviolet light sources such as mercury lamp or excimer laser.
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| CNB200410018034XA CN1312464C (en) | 2004-04-29 | 2004-04-29 | Field measurement method for aberration of imaging optical system |
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| WO2007112625A1 (en) * | 2006-04-04 | 2007-10-11 | Shanghai Micro Electronics Equipment Co., Ltd. | Method for in-situ aberration measurement of optical imaging system in lithographic tools |
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| JP3348419B2 (en) * | 1999-09-24 | 2002-11-20 | 株式会社東芝 | Aberration measurement method, aberration measurement system, and aberration measurement mask |
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