CN104777718B - A kind of large-numerical aperture wave aberration of photo-etching machine projection objective detection method - Google Patents
A kind of large-numerical aperture wave aberration of photo-etching machine projection objective detection method Download PDFInfo
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Abstract
A kind of large-numerical aperture wave aberration of photo-etching machine projection objective detection method, the present invention is divided into the modelling phase and aberration extracts the stage, modelling phase first sets the parameters such as the polarization state of light, the Polarization aberration of projection objective and numerical aperture, simulation space picture, principal component analysis and multiple linear regression analysis are carried out to simulation space picture, obtain corresponding principal component and regression matrix, the detection model that foundation is matched with large-numerical aperture litho machine；Aberration extracts phase acquisition actual measurement aerial image, and carrying out principal component fitting to actual measurement aerial image obtains principal component coefficient, and the Zernike polynomials fitting that least square fitting obtains surveying aerial image is carried out to principal component coefficient using regression matrix.The present invention realizes the Zernike polynomials fitting Z of large-numerical aperture projection lens of lithography machine5~Z37High precision test.
Description
Technical field
The present invention relates to projection lens of lithography machine, particularly a kind of large-numerical aperture wave aberration of photo-etching machine projection objective detection
Method.
Background technology
Litho machine is one of nucleus equipment of great scale integrated circuit manufacture.Projection objective is most important point of litho machine
One of system.The wave aberration of projection objective influences the image quality of litho machine, causes image contrast to reduce, process window contracting
It is small.As photoetching technique is developed to immersion from dry type, the tolerance for aberration of projection lens of lithography machine becomes more and more harsh, to ripple
The requirement of aberration accuracy of detection also more and more higher.Therefore, required to meet the alignment precision and resolution ratio etc. of litho machine, research and development one
Plant high-precision large-numerical aperture wave aberration of photo-etching machine projection objective detection technique significant.
2011, Lifeng Duan et al. proposed a kind of projection lens of lithography machine based on principal component of space image analysis
Wave aberration detection technique is (referring to first technology 1, Lifeng Duan, Xiangzhao Wang, Anatoly Y.Bourov, et
al.,“In situ aberration measurement technique based on principal component
analysis of aerial image,”Opt.Express 19(19),18080-18090(2011)).The technology uses water
The detection mark of gentle vertical both direction, under a kind of light illumination mode, detects that photoetching is thrown by gathering aerial image light distribution
Shadow objective wave aberration.The technology for detection high precision, speed is fast；But because mask detection mark only has both direction, it is only used for
Detection low order aberration (Z5,Z7~Z9,Z14~Z16), it is impossible to detect higher order Zernike polynomials fitting.
On the basis of above-mentioned technology, Duan Lifeng etc. has also been proposed a kind of projection objective wave aberration based on aerial image detection
In-situ measuring method is (referring to first technology 2, Duan Lifeng, Wang Xiangchao, Xu Dongbo, " the projection objective ripple picture based on aerial image detection
Difference in-situ measuring method ", the patent No.：ZL201210115759.5).The method is realized using the mask detection mark in 6 directions
Measurement (the Z of 33 rank Zernike polynomials fittings5~Z37), the method detects that mark realizes high-order Zernike polynomials fitting by increasing mask
Detection, but due to use scalar imaging model, may be only available for numerical aperture of projection objective less than/be equal to 0.75 situation,
Large-numerical aperture wave aberration of photo-etching machine projection objective cannot be detected.
The content of the invention
It is an object of the invention to provide a kind of large-numerical aperture projection lens of lithography machine ripple picture based on aerial image detection
Difference detection method, can accurately detect the wave aberration of large-numerical aperture projection lens of lithography machine.
Technical solution of the invention is as follows：
A kind of large-numerical aperture wave aberration of photo-etching machine projection objective detection method, the measuring system that the method is used includes using
In producing the light source of laser beam, illuminator, for bearing test mask and possess the mask platform of precise positioning ability, be used for
Detection on mask graph is marked the projection objective system being imaged onto on silicon chip, can carry silicon chip and has 3-D scanning ability
Work stage with precise positioning ability, the aerial image sensor in the work stage and it is connected with aerial image sensor
Data handling machine.
Described light source can be traditional lighting, ring illumination, the illumination of two poles, quadrupole illuminating and free lighting source, pass
The partial coherence factor of system lighting source is σ；The partial coherence factor of ring illumination light source is [σout,σin], σoutRepresent outside
Coherence factor, σinRepresent internal coherence factor；The partial coherence factor of two poles illumination is [σout,σin], σoutRepresent externally coherent
The factor, σinInternal coherence factor is represented, pole subtended angle is θ；The partial coherence factor of quadrupole illuminating is [σout,σin], σoutRepresent outer
Portion's coherence factor, σinInternal coherence factor is represented, pole subtended angle is θ.
Described illuminator is used to adjust light distribution and the polarization state of the illumination light field that the light source is produced.
Described detection mark by 6 there is the isolated sky that different directions are orientated to constitute, 6 different direction orientation difference
It is 0 °, 30 °, 45 °, 90 °, 120 °, 135 °.
The method includes that modelling phase and aberration extract the stage.
Modelling phase includes following 2 steps：
A. the establishment that simulation space image set is closed
33 rank Zernike polynomials fitting Z are set using Box-Behnken Design statistical sampling modes5~Z37Combination ZU, and
One group of Polarization aberration PT of large-numerical aperture projection lens of lithography machine is set at random；
Selection lithography simulation parameter：The lighting system and its partial coherence factor of illuminator, lighting system are shone for polarization
Bright, the polarization state of illumination light can be polarized completely, partial polarization and completely unpolarized, photo-etching machine exposal wavelength X, projection objective
Numerical aperture NA, the span for setting NA is NA >=0.93；
Test mask is placed in mask platform, the test badge on the test mask is isolated idle pattern；
Aerial image acquisition range：X-direction acquisition range is [- L, L], set the span of L as 300nm≤L≤
3000nm, Z-direction acquisition range is [- F, F], and the span for setting F is 2000nm≤F≤6000nm；Aerial image collection point
Number：X-direction collection points are M, and the span for set M be M >=20, and it is N that Z-direction collection is counted, set the span of N as
N≥13；By above-mentioned parameter and Zernike polynomials fitting combination ZU input computers, using the 1. shown vector imaging formula of formula, adopt
Emulated with photoetching simulation software, obtain simulation space image set and close AIU.
①
Wherein, nimageIt is the refractive index of image space,It is normalized efficient light sources intensity distribution,
It is pupil function,It is the diffraction spectra of mask,It is 3 × 2 transmission matrix, E0For Jones of incident light swears
Amount,*Represent conjugate transposition,WithWithRespectively normalized image coordinates, pupil areal coordinate, normalization formula is such as
Under：
②
Wherein, NA is the numerical aperture of projection objective, and λ is photo-etching machine exposal wavelength, and x and y, f and g are respectively image planes seat
Mark, pupil areal coordinate.
B. the demarcation of linear regression matrix
Closing AIU to simulation space image set carries out principal component analysis, obtains the principal component of simulation space picture and corresponding master
Composition coefficient, formula is as follows：
AIU=PCV is 3.
Wherein, PC is the principal component that simulation space image set is closed, and V is corresponding principal component coefficient.
Described principal component coefficient V and described Zernike polynomials fitting are combined into ZU as given data, using least square
Method approximating method calculates linear regression matrix RM, and formula is as follows：
V=ZURM is 4.
The aberration extraction stage includes following 2 steps：
A. the collection of aerial image is surveyed
Parameter setting is carried out to litho machine to be detected, parameter is identical with modelling phase step a.；
Start litho machine, the illumination light that light source sends after illuminator adjustment by obtaining corresponding to modelling phase step a.
Lighting system, be irradiated to the test mask in mask platform, utilization space as sensor measure through projection objective converge it is multi-party
To the corresponding aerial image of test badge, obtain surveying aerial image, and be input into the computer stored.
B. the solution of Zernike polynomials fitting
Principal component fitting is carried out to actual measurement aerial image using computer, obtains surveying the principal component coefficient of aerial image, then
It is fitted according to least square method with described linear regression matrix RM, obtains the Ze Nike pictures of surveyed projection lens of lithography machine
Difference.
Compared with first technology, the present invention has advantages below：
The present invention is by using polarized illumination mode and vector imaging model, it is contemplated that large-numerical aperture litho machine is projected
The Polarization aberration of object lens, the accurate characterization aerial image of large-numerical aperture litho machine realizes the projection of large-numerical aperture litho machine
Object lens Zernike polynomials fitting Z5~Z37High precision test.
Brief description of the drawings
Fig. 1 detecting system structure charts of the present invention.
Fig. 2 lighting system structural representations of the present invention.
Fig. 3 mask mark structure schematic diagrames of the present invention.
The large-numerical aperture wave aberration of photo-etching machine projection objective precision figure that Fig. 4 is obtained using present invention measurement.
Specific embodiment
With reference to embodiment and accompanying drawing, the invention will be further described, but should not limit the present invention with this embodiment
Protection domain.
Fig. 1 is the detecting system structural representation that the present invention is used.Produce light source 1, illuminator 2, the use of laser beam
In bearing test mask 3 and possess the mask platform 4 of precise positioning ability, for the detection mark 5 on mask graph to be imaged onto
Projection objective system 6 on silicon chip, the work stage 7 that silicon chip can be carried and there is 3-D scanning ability and precise positioning ability, peace
Aerial image sensor 8 in the work stage 7 and the data handling machine 9 being connected with aerial image sensor 8.
The method includes that modelling phase and aberration extract the stage.
Modelling phase includes following 2 steps：
A. the establishment that simulation space image set is closed
The 33 ranks pool of [- 0.02 λ, 0.02 λ] amplitude range is set using Box-Behnken Design statistical sampling modes
Buddhist nun gram aberration Z5~Z37Combination ZU and set one group of Polarization aberration PT of large-numerical aperture projection lens of lithography machine at random；
Selected lithography simulation parameter：The lighting system of illuminator chooses ring illumination, and its partial coherence factor is [σout,
σin]=[0.9,0.7], the polarization state of illumination light chooses linearly polarized light, direction of vibration and the X-axis side of the linearly polarized light light vector
To parallel, as shown in Fig. 2 photo-etching machine exposal wavelength X=193nm, the numerical aperture NA=1.35 of projection objective；
Test mask is placed in mask platform, the test badge on the test mask is isolated idle pattern, the combination there are 6
Isolated sky with different directions orientation, 6 described respectively 0 ° of direction orientations for isolating sky, 30 °, 45 °, 90 °, 120 °,
135 °, as shown in Figure 3；
Aerial image acquisition range：X-direction acquisition range be [- 900nm, 900nm ,] Z-direction acquisition range for [- 2000,
2000；] aerial image collection points：X-direction collection points are 61, and Z-direction collection points are 57；By above-mentioned parameter design and damp Buddhist nun
Gram aberration combination ZU input computers, using the 1. shown vector imaging formula of formula, are emulated using lithography simulation software,
Obtain simulation space image set and close AIU.
①
Wherein, nimageIt is the refractive index of image space,It is normalized efficient light sources intensity distribution,
It is pupil function,It is the diffraction spectra of mask,It is 3 × 2 transmission matrix, E0For Jones of incident light swears
Amount,*Represent conjugate transposition,WithWithRespectively normalized image coordinates, pupil areal coordinate, normalization formula is such as
Under：
②
Wherein, NA is the numerical aperture of projection objective, and λ is photo-etching machine exposal wavelength, and x and y, f and g are respectively image planes seat
Mark, pupil areal coordinate.
B. the demarcation of linear regression matrix
Closing AIU to simulation space image set carries out principal component analysis, obtains the principal component of simulation space picture and corresponding master
Composition coefficient, formula is as follows：
AIU=PCV is 3.
Wherein, PC is the principal component that simulation space image set is closed, and V is corresponding principal component coefficient.
Described principal component coefficient V and described Zernike polynomials fitting are combined into ZU as given data, using least square
Method approximating method calculates linear regression matrix RM, and formula is as follows：
V=ZURM is 4.
The aberration extraction stage includes following 2 steps：
A. the collection of aerial image is surveyed
Parameter setting is carried out to litho machine to be detected, parameter is identical with modelling phase step a.；
Start litho machine, the illumination light that light source sends after illuminator adjustment by obtaining corresponding to modelling phase step a.
Lighting system, be irradiated to the test mask in mask platform, utilization space as sensor measure through projection objective converge it is multi-party
To the corresponding aerial image of test badge, obtain surveying aerial image, and be input into the computer stored.
B. the solution of Zernike polynomials fitting
Principal component fitting is carried out to actual measurement aerial image using computer, obtains surveying the principal component coefficient of aerial image, then
It is fitted according to least square method with described linear regression matrix RM, obtains the Ze Nike pictures of surveyed projection lens of lithography machine
Difference, as shown in Figure 4.The mean error and standard deviation of the Zernike polynomials fitting that detection is obtained are in below 0.07nm.
Relative to first technology, this method is by using polarized illumination mode and vector imaging model, it is contemplated that big number
It is worth the Polarization aberration of aperture projection lens of lithography machine, the accurate characterization aerial image of large-numerical aperture litho machine realizes big number
Value aperture projection lens of lithography machine Zernike polynomials fitting Z5~Z37High precision test.
Principle that embodiment of above is intended to be merely illustrative of the present and the illustrative embodiments that use, but this hair
It is bright to be not limited thereto.For those skilled in the art, the feelings of spirit and substance of the present invention are not being departed from
Under condition, various changes and modifications can be made therein, therefore all equivalent technical schemes fall within scope of the invention, of the invention
Scope of patent protection should be defined by the claims.
Claims (4)
1. a kind of large-numerical aperture wave aberration of photo-etching machine projection objective detection method, the measuring system that the method is used includes being used for
Produce the light source (1) of laser beam, illuminator (2), for bearing test mask (3) and possess the mask of precise positioning ability
Platform (4), for by mask graph detection mark (5) be imaged onto on silicon chip projection objective system (6), silicon chip can be carried simultaneously
Work stage (7) with 3-D scanning ability and precise positioning ability, the aerial image sensor in the work stage (7)
(8) data handling machine (9) and with aerial image sensor (8) being connected；The method uses polarized illumination mode and arrow
Amount imaging model, it is characterised in that extract the stage including modelling phase and aberration；
The described modelling phase includes following 2 steps：
A. the establishment that simulation space image set is closed
33 rank Zernike polynomials fitting Z are set using Box-Behnken Design statistical sampling methodses5~Z37Combination ZU, and at random
Set one group of Polarization aberration PT；
Selection lithography simulation parameter：The lighting system and its partial coherence factor of illuminator, photo-etching machine exposal wavelength X, projection
The numerical aperture NA of object lens；
Test mask is placed in mask platform, the test badge on the test mask is isolated idle pattern；
Installation space is as acquisition range：X-direction acquisition range is [- L, L], and Z-direction acquisition range is [- F, F]；Aerial image is gathered
Points：X-direction collection points are M, and Z-direction collection points are N；
By above-mentioned parameter and Zernike polynomials fitting combination ZU input computers, emulated using lithography simulation software, emulated
Aerial image set AIU；
B. the demarcation of linear regression matrix
Closing AIU to simulation space image set carries out principal component analysis, obtains the principal component and corresponding principal component of simulation space picture
Coefficient, formula is as follows:
AIU=PCV is 1.
Wherein, PC is the principal component that simulation space image set is closed, and V is corresponding principal component coefficient；
Described principal component coefficient V and described Zernike polynomials fitting are combined into ZU as given data, is intended using least square method
Conjunction method calculates linear regression matrix RM, and formula is as follows：
V=ZURM is 2.
The described aberration extraction stage includes following 2 steps：
A. the collection of aerial image is surveyed
Parameter setting is carried out to litho machine to be detected, parameter is identical with modelling phase step a.；
Start litho machine, the illumination light that light source sends after illuminator adjustment by obtaining shine corresponding with modelling phase step a.
Bright mode, is irradiated to the test mask in mask platform, and utilization space measures the multi-direction survey converged through projection objective as sensor
Corresponding aerial image is remembered in test-object, obtains surveying aerial image, and be input into the computer stored；
B. the solution of Zernike polynomials fitting
Principal component fitting is carried out to actual measurement aerial image using computer, obtains surveying the principal component coefficient of aerial image, then with institute
The linear regression matrix RM for stating is fitted according to least square method, obtains the Zernike polynomials fitting of surveyed projection lens of lithography machine；
Described light source is traditional lighting, ring illumination, the illumination of two poles, quadrupole illuminating or free lighting source, traditional lighting light
The partial coherence factor in source is σ；The partial coherence factor of ring illumination light source is [σout,σin], σoutThe externally coherent factor is represented,
σinRepresent internal coherence factor；The partial coherence factor of two poles illumination is [σout,σin], σoutRepresent the externally coherent factor, σinTable
Show internal coherence factor, pole subtended angle is θ；The partial coherence factor of quadrupole illuminating is [σout,σin], σoutRepresent externally coherent because
Son, σinInternal coherence factor is represented, pole subtended angle is θ；
Described illuminator is used to adjust light distribution and the polarization state of the illumination light field that the light source is produced；
Described detection mark by 6 there is the isolated sky that different directions are orientated to constitute, and 6 different direction orientations are respectively
0 °, 30 °, 45 °, 90 °, 120 ° and 135 °.
2. large-numerical aperture wave aberration of photo-etching machine projection objective detection method according to claim 1, it is characterised in that institute
The polarization state of the light stated is to polarize completely, partial polarization or completely unpolarized.
3. large-numerical aperture wave aberration of photo-etching machine projection objective detection method according to claim 1, it is characterised in that institute
The span of the X-direction acquisition range L for stating is 300nm≤L≤3000nm；The span of Z-direction acquisition range F is
2000nm≤F≤6000nm；The span of X-direction collection points M is M >=20, and the span of Z-direction collection points N is N
≥13。
4. large-numerical aperture wave aberration of photo-etching machine projection objective detection method according to claim 1, it is characterised in that institute
Numerical aperture NA >=0.93 of the projection objective stated.
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| CN105372948B (en) * | 2015-11-09 | 2017-09-12 | 中国科学院上海光学精密机械研究所 | Large-numerical aperture wave aberration of photoetching projection objective detection method based on rapid modeling |
| CN105301752B (en) * | 2015-11-18 | 2018-02-02 | 山西大学 | A kind of near-infrared long reach monochrome microcobjective of NA=0.4 |
| CN105629677A (en) * | 2016-01-18 | 2016-06-01 | 中国科学院上海光学精密机械研究所 | Higher-order wave aberration detection mark and detection method of photoetching projection objective lens |
| CN108170006B (en) * | 2017-12-12 | 2019-10-18 | 中国科学院上海光学精密机械研究所 | Litho machine matching process |
| CN108020400A (en) * | 2017-12-12 | 2018-05-11 | 中国科学院上海光学精密机械研究所 | Photoetching projection objective lens high-rank wavefront aberration detection method based on more polarization illuminations |
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| CN102346368A (en) * | 2010-07-23 | 2012-02-08 | 中芯国际集成电路制造(上海)有限公司 | Method for manufacturing double pattern exposure mask and double pattern exposure method |
| CN102411267A (en) * | 2011-11-30 | 2012-04-11 | 上海华力微电子有限公司 | Exposure method adopting lithography machine |
| CN102681358A (en) * | 2012-04-18 | 2012-09-19 | 中国科学院上海光学精密机械研究所 | Space image detection-based projection objective wave aberration in-situ measurement method |
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| JP5428671B2 (en) * | 2009-09-08 | 2014-02-26 | 株式会社ニコン | Exposure method, device manufacturing method, and exposure system |
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| CN102346368A (en) * | 2010-07-23 | 2012-02-08 | 中芯国际集成电路制造(上海)有限公司 | Method for manufacturing double pattern exposure mask and double pattern exposure method |
| CN102411267A (en) * | 2011-11-30 | 2012-04-11 | 上海华力微电子有限公司 | Exposure method adopting lithography machine |
| CN102681358A (en) * | 2012-04-18 | 2012-09-19 | 中国科学院上海光学精密机械研究所 | Space image detection-based projection objective wave aberration in-situ measurement method |
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