WO2018064827A1 - 一种可标定系统误差的系统波像差检测方法 - Google Patents

一种可标定系统误差的系统波像差检测方法 Download PDF

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WO2018064827A1
WO2018064827A1 PCT/CN2016/101556 CN2016101556W WO2018064827A1 WO 2018064827 A1 WO2018064827 A1 WO 2018064827A1 CN 2016101556 W CN2016101556 W CN 2016101556W WO 2018064827 A1 WO2018064827 A1 WO 2018064827A1
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grating
sub
projection objective
spatial filter
phase shift
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PCT/CN2016/101556
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English (en)
French (fr)
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于长淞
高松涛
彭石军
苗二龙
隋永新
杨怀江
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中国科学院长春光学精密机械与物理研究所
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Priority to PCT/CN2016/101556 priority Critical patent/WO2018064827A1/zh
Publication of WO2018064827A1 publication Critical patent/WO2018064827A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G01M11/02—Testing optical properties
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/20—Exposure; Apparatus therefor

Definitions

  • the invention relates to the technical field of optical detection, in particular to a system wave aberration detection method capable of calibrating system errors.
  • Optical projection lithography is an optical exposure process that uses an optical projection imaging principle to transfer a high-resolution IC pattern on a reticle onto a coated silicon wafer. This is the most widely used in the manufacturing process of VLSI. Wide and technologically advanced lithography technology. The lithography process directly determines the feature size of large-scale integrated circuits, and is the key process for large-scale integrated circuit manufacturing. The lithography machine projection objective lens is the core component of the lithography process and the most difficult sub-system.
  • the exposure wavelength of the lithography machine has been developed from 436 nm (g line), 365 nm (i line), 248 nm (KrF) to 193 nm (ArF), and the numerical aperture of the projection objective lens is increased by continuously reducing the exposure wavelength. And reduce the lithography process factor to achieve smaller feature sizes.
  • the immersion technique is used to make the numerical aperture of the projection objective of the lithography machine reach 1.3 or higher.
  • the feature size of the chip which can be realized by the lithography process using the ArF light source extends to the node below 45 nm.
  • the lithographic projection objective system wave aberration is one of the landmark indicators for evaluating the performance of the lithography machine. It directly affects the key indicators such as lithography machine imaging quality, lithography resolution and feature size uniformity.
  • the wavefront aberration should be better than 10 m ⁇ (2 nm). This requires the development and possession of sub-nanometer precision system wave aberration detection technology and equipment to accurately measure the system wave of the projection objective.
  • Aberration evaluate the feature line width that it can achieve, and provide a guiding quantitative basis for further ultra-precision assembly and grinding of the projection objective, and then put forward higher requirements for the wave aberration detection method.
  • the device for detecting the wave aberration of the projection objective system of the lithography machine includes a Point Diffraction Interferometer, a Line Diffraction Interferometer, a Lateral Shearing Interferometer, and the like.
  • the transverse shear interferometer with Ronchi is an effective method for evaluating and measuring the image difference of lithographic projections. It has been proven to perform well in lithography detection in the 193 nm deep ultraviolet band.
  • the transverse shear interferometer is easier to adjust and align with respect to the point diffraction interferometer and has higher streaks Contrast, which can be used for measurement of large numerical aperture lithography objectives, with high detection accuracy.
  • the patent CN102368139B uses a grating interferometer based on a grating diffraction to measure the wave aberration of the projection objective, and by rotating the absolute calibration method of the projection objective to be measured, plus two off-axis points. Measure and calibrate the systematic error of the interferometer measurement system.
  • the method has strict requirements on the technical indexes such as eccentricity and tilt during the rotation of the projection objective to be tested, so that not only a rotating mechanism with strong bearing capacity is required, but also the rotation mechanism requires extremely high positioning accuracy and repeatability. This is very difficult to implement in the project.
  • the method of separating systematic errors by rotating the projection objective to be measured has great limitations for high NA projection objectives using mirrors and off-axis optics.
  • the object of the present invention is to provide a system wavefront aberration detecting method capable of calibrating system errors, so as to solve the problem of system error affecting system wave aberration detection accuracy.
  • the invention provides a system wavefront aberration detecting method capable of calibrating system errors, comprising: Step A: detecting a projection objective lens by using a shear interference detecting system, and obtaining a system wave aberration of the measured projection objective,
  • the system wave aberration includes the actual wave aberration of the projection objective to be measured and the systematic error of the detection system; step B: removing the projection objective to be measured to obtain a systematic error of the shear interference detection system; and step C: by the measured
  • the system wave aberration of the projection objective and the systematic error of the shear interference detection system obtain the actual wave aberration of the projection objective to be measured.
  • the shear interference detecting system comprises: a test beam generating subsystem and a sensor module 12; the test beam generating subsystem comprises: a second converging lens 7; the projection objective 8 to be measured is located at the second converging lens 7 and the sensor Between the modules 12, the object focal plane of the measured projection objective coincides with the image focal plane of the second converging lens; the test beam emitted by the second converging lens enters the projection objective 8 to be measured, the measured projection The outgoing beam of the objective lens is incident on the sensor module 12; in step B, the projected objective lens 8 is measured from the second converging lens 7 and the sensor module Remove between 12 to obtain systematic errors in the shear interference detection system.
  • the sensor module 12 includes a spatial filter 202; the step B includes: sub-step B1: removing the measured objective lens 8 and moving the sensor module 12 under the second converging lens 7
  • the spatial filter 202 coincides with the image focal plane of the second converging lens; sub-step B2: obtaining a first set of phase-shifting interference fringe patterns and a second set of phase-shifting interference fringe patterns; sub-step B3: for the first group
  • the phase shift interference fringe pattern and the second set of phase shift interference fringe patterns are processed to obtain the systematic error of the shear interference detection system.
  • the sensor module 12 further includes: a beam splitting device 201, an image sensor 11, a phase shifting device 9 that moves the two-dimensional direction of the beam splitting device, and a fine-motion stage 10 that carries the spatial filter in a two-dimensional direction.
  • the beam splitting device 201 includes a first grating 201a and a second grating 201b whose scribe directions are orthogonal to each other;
  • the sub-step B2 includes sub-step B2a: causing the phase shifting device 9 to drive the beam splitting device 201 vertically Moving in the reticle direction of the first grating 201a, introducing an ordered phase shift in the diffracted light, causing the micro-motion stage 10 to drive the spatial filter 202 to follow the position of the beam splitting device 201 to match the first grating, and obtain a vertical a first set of phase shift interference fringe patterns in the reticle direction of the first grating 201a; sub-step B2b: causing the phase shifting device 9 to drive the beam splitting device 201 to move in a direction perpendicular to the reticle of the second grating 201b, in the diffracted light An ordered phase shift is introduced to cause the micro-motion stage 10 to drive the spatial filter 202 to follow the position where the beam splitting device 201 is moved
  • the test beam forms diffracted light after passing through the first grating 201a; in the sub-step B2b, the test beam forms diffracted light after passing through the second grating 201b;
  • the zero-order and high-order diffracted lights are cut off by the spatial filter 202, and the ⁇ 1 order diffracted light passes through the two windows of the spatial filter and is incident on the image sensor.
  • the sub-step B3 includes: performing phase extraction and phase unwrapping on the first set of phase shift interference fringe patterns and the second set of phase shift interference fringe patterns, and performing wavefront fitting using a differential Zernike polynomial to obtain 36 items of Zernike The systematic error W system represented by the coefficient.
  • the step A includes: sub-step A1: obtaining a third set of phase-shifting interference fringe patterns and a fourth set of phase-shifting interference fringe patterns; sub-step A2: performing a third set of phase-shifting interference fringe patterns and fourth The phase shift interference fringe pattern is processed to obtain the system wave aberration of the projection objective to be measured.
  • the sensor module 12 includes: a beam splitting device 201, a spatial filter 202, an image sensor 11, a phase shifting device 9 that carries the beam splitting device to move in a two-dimensional direction, and a micro-carrier moving in a two-dimensional direction.
  • the splitting device 201 includes a first grating 201a and a second grating 201b whose scribe directions are orthogonal to each other; the sub-step A1 includes: sub-step A1a: causing the phase shifting device 9 to drive the splitting The device 201 moves in a direction perpendicular to the reticle of the first grating 201a, introducing an ordered phase shift in the diffracted light, causing the micro-motion stage 10 to drive the spatial filter 202 to follow the position of the beam splitting device 201 to match the first grating.
  • phase shifting device 9 to drive the beam splitting device 201 to move in a direction perpendicular to the reticle of the second grating 201b, Introducing an ordered phase shift in the diffracted light, causing the micro-motion stage 10 to drive the spatial filter 202 to follow the position where the beam splitting device 201 is moved to match the second grating to obtain a fourth direction perpendicular to the reticle direction of the second grating 201b.
  • the outgoing beam of the projection objective to be measured forms diffracted light after passing through the first grating 201a; in the sub-step A1b, the outgoing beam of the projection objective to be measured is The second grating 201b is followed by diffracted light; and, in the sub-step A1a and the sub-step A1b, the zero-order and higher-order diffracted lights are cut off by the spatial filter 202, and the ⁇ 1 order diffracted light is spatially filtered.
  • the window of the device is incident on the image sensor 11.
  • the sub-step A2 includes: performing phase extraction and phase unwrapping on the third set of phase shift interference fringe patterns and the fourth set of phase shift interference fringe patterns, and performing wavefront fitting using a differential Zernike polynomial to obtain 36 items of Zernike The system wave aberration W 1 of the measured projection objective represented by the polynomial coefficient.
  • W real represents the actual wave aberration of the projection objective being measured
  • W system represents the systematic error of the shear interference detection system
  • the step C comprises: subtracting the system wave aberration of the measured projection objective from the systematic error of the shear interference detecting system to obtain the actual wave aberration of the measured projection objective.
  • the test beam generating subsystem further includes, in order of the propagation direction of the test beam, a light source 1, an illumination system 2, a first converging lens 3, a small aperture spatial filter 4, a collimating mirror 5, and a mirror 6;
  • the illumination beam emitted by the light source 1 sequentially passes through the coaxially disposed illumination system 2, the first converging lens 3, the aperture spatial filter 4, and the collimating mirror 5, and is rotated by the mirror 6 to 90. After that, it is transmitted through the second converging lens 7 to generate a test beam.
  • the small-pore spatial filter used in the invention can play the role of filtering, can eliminate the aberration caused by the illumination system and the first converging lens, and improve the detection precision of the system wave aberration;
  • the spatial filter allows only ⁇ 1 order diffracted light to pass through the window in the spatial filter, and the zero-order and higher-order diffracted light is cut off by the spatial filter, thereby reducing noise and improving measurement accuracy;
  • FIG. 1 is a flow chart of a system wavefront aberration detecting method capable of calibrating system errors according to an embodiment of the present invention
  • FIG. 2 is a schematic diagram of a shear interference detecting system for detecting a wave aberration of a system according to an embodiment of the present invention
  • FIG. 3 is a schematic diagram of a shear interference detection system for detecting system errors according to an embodiment of the present invention
  • FIG. 4 is a schematic diagram of a beam splitting device according to an embodiment of the present invention.
  • 1-light source 2-illumination system; 3-first convergent lens; 4-hole spatial filter; 5-collimator; 6-mirror; 7-second convergent lens; 8--projection objective; - phase shifting device; 10 - micro-motion table; 11 - image sensor; 12 - sensor module;
  • 201-beam splitting device 201a - first grating; 201b - second grating; 202 - spatial filter.
  • the present invention proposes a system wave aberration detection method that can calibrate system errors.
  • FIG. 1 is a flow chart showing a system wavefront aberration detecting method for calibrating system errors according to an embodiment of the present invention.
  • the system wave aberration detection method includes:
  • Step A Using the shear interference detection system to detect the projection objective to be measured, and obtain the system wave aberration of the projection objective to be measured, the system wave aberration includes the actual wave aberration of the projection objective to be measured and the systematic error of the detection system.
  • the detecting system includes: a test beam generating subsystem and a sensor module 12;
  • the test beam generating subsystem includes: a light source 1, an illumination system 2, and a first converging lens 3 , a small aperture spatial filter 4, a collimating mirror 5, a mirror 6 and a second converging lens 7.
  • the projection objective 8 to be measured is located between the second converging lens 7 and the sensor module 12, and the projection objective 8 to be measured can be removed from the shear interference detecting system.
  • the light source 1 generates an illumination beam
  • the light source 1, the illumination system 2, the first converging lens 3, the small-pore spatial filter 4, and the collimating mirror 5 are sequentially disposed coaxially, and the mirror 6 is disposed at an angle of 45 degrees with the optical axis.
  • the second converging lens 7, the projection objective 8 to be measured, and the sensor module 12 are sequentially disposed on the optical axis at which the mirror 6 is deflected by 90 degrees.
  • the sensor module 12 includes a beam splitting device 201, a spatial filter 202, a phase shifting device 9, a fine motion stage 10, and an image sensor 11.
  • the light source 1 may be an ArF excimer laser, a KrF excimer laser or a visible light band laser;
  • the illumination system 2 is a beam expander lens group or a beam shaper;
  • the first converging lens 3 and the collimator lens 5 are made of fused silica and plated with The optical antireflection film;
  • the image plane of the first converging lens 3 coincides with the object plane of the collimating mirror 5, and the small hole spatial filter 4 is located at the focus of the first converging lens 3 and the collimating mirror 5,
  • the small hole spatial filter 4 can be prepared by electron beam exposure or reactive ion beam etching method, the pinhole diameter of the small hole spatial filter 4 is smaller than the diffraction limit resolution of the illumination beam to play the role of filtering, eliminating the illumination system 2 and the first converging lens 3 caused aberrations to improve the detection accuracy of system wave aberrations.
  • the mirror 6 is placed at 45° in the horizontal direction (optical axis) and plated with an anti-reflection film;
  • the second converging lens 7 adopts an object-side telecentric structure, and the image focal plane of the second converging lens 7 and the projection objective 8 to be measured
  • the object focal planes coincide, the second converging lens 7 is made of fused silica and coated with an anti-reflection film;
  • the projection objective is a full transmissive projection objective, a refraction projection objective or a total reflection projection objective.
  • the beam splitting device 201 uses a binary amplitude grating or a binary phase grating, due to system wave aberration detection
  • the measurement method adopts the principle of shear interference, and the wave aberration of the projection objective system needs to be measured twice in the orthogonal direction. Therefore, the beam splitting device 201 is composed of two gratings whose orthogonal directions, the period and the duty ratio are exactly the same -
  • the first grating 201a and the second grating 201b are composed, the reticle of the first grating 201a is in a first direction (as in the x direction in FIG. 4), and the reticle of the second grating 201b is in a second direction perpendicular to the first direction ( As shown in the y direction in Figure 4).
  • the orthogonally placed spatial filter 202 is composed of two windows whose window size and center distance are such that when the diffracted light passes through the spatial filter, only ⁇ 1 order diffracted light can pass through the window in the spatial filter 202, zero order and more.
  • the higher order diffracted light is cut off by the spatial filter 202, so that the noise is reduced and the measurement accuracy is improved.
  • the widths of the two windows are equal and satisfy the formula (1):
  • ⁇ is the wavelength of the light source
  • NA i is the image square numerical aperture of the projection objective 8 to be measured
  • f is the spatial frequency of the chopped aberration of the projection objective 8 to be measured.
  • the base material of the spatial filter 202 is silicon or fused silica, etc., and an anti-ultraviolet layer material such as chromium, nickel or ruthenium is deposited on the base material, and a desired square window is prepared by electron beam exposure or reactive ion beam etching.
  • the phase shifting device 9 employs a piezoelectric ceramic micro-displacement stage capable of carrying the beam splitting device 201 to accurately move in a two-dimensional direction, by pushing the beam splitting device 201 along a line perpendicular to the first grating 201a and perpendicular to the second grating 201b. The direction moves to introduce a phase shift between the diffracted lights.
  • step A first, the light source 1 emits an illumination beam.
  • the illumination system 2 adjusts the intensity distribution and the illumination mode.
  • the exit beam of the illumination system passes through the first converging lens 3 and is incident on the small hole spatial filter.
  • the object 4 is diffracted by the small-space spatial filter 4 to generate an ideal spherical wavefront.
  • the spherical wavefront is expanded into a parallel beam by the collimating objective lens 5, and is incident on the mirror 6.
  • the parallel beam is deflected by the mirror 6 and then rotated 90.
  • the second converging lens 7 is incident on the degree.
  • the parallel beam passes through the second converging lens 7 and enters the projection objective 8 to be measured and fills the entire field of view of the projection objective 8 to be measured.
  • the outgoing beam of the projection objective 8 to be measured carries system wave aberration information.
  • the outgoing beam of the projection objective 8 to be measured is incident on the sensor module 12, and after the beam splitting device 201 and the spatial filter 202 of the sensor module 12, the phase-shifted ⁇ 1 order diffracted light interferes to form a perpendicular to the first grating.
  • the third set of phase shift interference fringes and sag in 201a reticle direction A fourth set of phase shift interference fringe patterns straight to the reticle direction of the second grating 201b.
  • the steps of forming the third set of phase shift interference fringe patterns perpendicular to the reticle direction of the first grating 201a and the fourth set of phase shift interference fringe patterns perpendicular to the reticle direction of the second grating 201b include:
  • the outgoing beam is incident on the first grating 201a to form diffracted light, so that the phase shifting device 9 drives the beam splitting device 201 to move in a direction perpendicular to the first grating 201a, thereby introducing an ordered phase shift in the diffracted light, so that the micro-motion stage
  • the 10-driven spatial filter 202 follows the beam splitting device 201 to a position matching the first grating 201a such that the zero-order and higher-order diffracted lights are cut off by the spatial filter 202, and only the ⁇ 1 order diffracted light can pass through the spatial filter 202.
  • two windows are incident on the image sensor 11, forming a third set of phase shift interference fringe patterns perpendicular to the reticle direction (Y direction) of the first grating 201a;
  • the exiting beam is incident on the second grating 201b to form diffracted light
  • the phase shifting device 9 drives the beam splitting device 201 to move in a direction perpendicular to the reticle of the second grating 201b, thereby introducing an ordered phase shift in the diffracted light, so that the micro-motion stage 10
  • the spatial filter 202 is driven to follow the position where the beam splitting device 201 is moved to match the second grating 201b such that the zero-order and higher-order diffracted light is cut off by the spatial filter 202, and only the ⁇ 1 order diffracted light can pass through the spatial filter 202.
  • the two windows are incident on the image sensor 11 to form a fourth set of phase shift interference fringe patterns perpendicular to the reticle direction (X direction) of the second grating 201b.
  • the third set of phase shift interference fringe pattern and the fourth set of phase shift interference fringe pattern are processed to obtain the system wave aberration of the measured projection objective.
  • the third phase shift interference fringe pattern perpendicular to the reticle direction of the first grating 201a and the fourth phase shift interference fringe pattern perpendicular to the reticle direction of the second grating 201b may be phase-extracted and phase-expanded by a computer.
  • the wavefront fitting is performed by differential Zernike polynomial, and the system wave aberration W 1 of the measured projection objective represented by 36 Zernike polynomial coefficients is obtained.
  • W 1 W real +W system
  • W real represents the actual wave aberration of the projection objective being measured
  • W system represents the systematic error of the shear interference detection system, which includes the systematic error introduced by the illumination system and the convergence lens. Ill and the system error W sensor introduced by the sensor module.
  • Step B Remove the projection objective to be measured, and obtain the systematic error of the shear interference detection system.
  • the structure of the shear interference detecting system of step B is as shown in FIG. 3, which is different from the structure shown in FIG. 2 in that the detecting system removes the projection objective 8 to be measured, and the spatial filter 202 of the sensor module is combined with the second.
  • the image focal planes of the lenses 7 coincide.
  • step B the projection objective 8 to be measured is preferably removed, and the sensor module 12 is moved below the second converging lens 7 such that the spatial filter 202 of the sensor module coincides with the image focal plane of the second converging lens 7.
  • the light source 1 emits an illumination beam.
  • the illumination system 2 adjusts the intensity distribution and the illumination mode.
  • the exit beam of the illumination system passes through the first converging lens 3 and is incident on the aperture spatial filter 4, which is small.
  • the hole spatial filter 4 is diffracted to generate an ideal spherical wavefront
  • the spherical wavefront is expanded into a parallel beam by the collimating objective lens 5, and is incident on the mirror 6.
  • the parallel beam is rotated by the mirror 6 and then rotated 90 degrees to the second.
  • the outgoing beam of the second converging lens 7 is incident on the sensor module 12, and after the beam splitting device 201 and the spatial filter 202 of the sensor module 12, the phase-shifted ⁇ 1 order diffracted light interferes to form a perpendicular to the first grating.
  • substep A3 The specific process of forming the first set of phase shift interference fringe patterns perpendicular to the reticle direction of the first grating 201a and the second set of phase shift interference fringe patterns perpendicular to the reticle direction of the second grating 201b is similar to substep A3, specifically include:
  • the outgoing beam is incident on the first grating 201a to form diffracted light, so that the phase shifting device 9 drives the beam splitting device 201 to move in a direction perpendicular to the first grating 201a, thereby introducing an ordered phase shift in the diffracted light, so that the micro-motion stage
  • the 10-driven spatial filter 202 follows the beam splitting device 201 to a position matching the first grating 201a such that the zero-order and higher-order diffracted lights are cut off by the spatial filter 202, and only the ⁇ 1 order diffracted light can pass through the spatial filter 202.
  • the two windows are incident on the image sensor 11 to form a first set of phase shift interference fringe patterns perpendicular to the reticle direction (Y direction) of the first grating 201a;
  • the outgoing beam is incident on the second grating 201b to form diffracted light, so that the phase shifting device 9 drives the beam splitting device 201 to move in a direction perpendicular to the reticle of the second grating 201b, thereby introducing an ordered phase shift in the diffracted light, so that the micro-motion stage
  • the 10-driven spatial filter 202 follows the position where the beam splitting device 201 is moved to match the second grating 201b such that the zero-order and higher-order diffracted lights are cut off by the spatial filter 202, and only the ⁇ 1 order diffracted light can pass through the spatial filter 202.
  • the two windows are incident on the image sensor 11 to form a second set of phase shift interference fringe patterns perpendicular to the reticle direction (X direction) of the second grating 201b.
  • the first phase shift interference fringe pattern perpendicular to the reticle direction of the first grating 201a and the second set of phase shift interference fringe pattern perpendicular to the reticle direction of the second grating 201b are phase-extracted and phase-expanded by using a computer.
  • the differential Zernike polynomial performs wavefront fitting, and the systematic error W 2 represented by 36 Zernike coefficients is obtained.
  • the measurement result W 2 includes only the illumination system, the systematic error Will introduced by the convergent lens, and the system error W sensor introduced by the sensor module, so after removing the projection objective to be measured
  • the obtained measurement result W 2 can be expressed as a systematic error W system , thereby obtaining a systematic error W system represented by the Zernike coefficient and stored in a computer.
  • Step C The system wave aberration of the measured projection objective obtained in step A is subtracted from the systematic error of the shear interference detecting system obtained in step B, and the actual wave aberration of the projected objective lens is obtained.
  • the system wave aberration W 1 of the projection objective to be measured is subtracted from the systematic error W system of the shear interference detection system, and the actual wave aberration W real of the projection objective to be measured is obtained, thereby eliminating the influence of systematic errors, thereby improving the measurement. Accuracy, ultimately obtaining systematic wave aberrations of a highly accurate projection objective.
  • the system for detecting the projection objective is detected by the shear interference detection system, the system wave aberration of the projection objective to be measured is obtained, and the projection objective lens is removed to obtain the system of the shear interference detection system.
  • the order of the above two steps may be interchanged, that is, the present invention may also first measure the shear interference detection system, obtain the systematic error of the shear interference detection system, and then measure The projection objective is placed between the second converging lens and the sensor module, so that the object focal plane of the projection objective to be measured coincides with the image focal plane of the second converging lens, and the projection objective is detected by the shear interference detection system.
  • the actual wave aberration of the projection objective to be measured can also be obtained, and the shear interference detection system is first measured. After obtaining the systematic error of the shear interference detection system, the systematic error can be obtained.
  • the projection objective lens of different types and different parameters can be calibrated, which has wide applicability and convenient operation.
  • optical component in the optical path can also take other forms as long as the same function can be achieved

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Abstract

一种可标定系统误差的系统波像差检测方法，将被测投影物镜（8）的系统波像差与剪切干涉检测系统的系统误差相减，获得被测投影物镜（8）实际波像差，消除了系统误差的影响，提高了测量精度；采用的小孔空间滤波器（4）可以起到滤波的作用，可以消除照明系统（2）及第一汇聚透镜（3）所导致的像差，提高了系统波像差的检测精度；空间滤波器（202）使得只有±1级衍射光才能通过空间滤波器（202）中的窗口，零级以及更高级次的衍射光都被空间滤波器（202）截止，从而使得噪声减小并且测量精度获得改善。

Description

一种可标定系统误差的系统波像差检测方法 技术领域
本发明涉及光学检测技术领域，尤其涉及一种可标定系统误差的系统波像差检测方法。
背景技术
光学投影光刻是利用光学投影成像的原理，将掩模版上高分辨力的IC图形以曝光的方式转移到涂胶硅片上的光学曝光过程，是当今在超大规模集成电路制造过程中应用最广、技术进步最快的光刻技术。光刻工艺直接决定了大规模集成电路的特征尺寸，是大规模集成电路制造的关键工艺，而光刻机投影物镜则是光刻工艺的核心部件，也是难度最大的分系统。
经过多年的发展光刻机的曝光波长已经从436nm(g线)、365nm(i线)、248nm(KrF)发展到193nm(ArF)，通过不断减小曝光波长，增大投影物镜的数值孔径，并降低光刻工艺因子，以获得更小的特征尺寸。采用浸没式技术使光刻机投影物镜的数值孔径达到1.3以上，配合其他分辨率增强技术使得采用ArF光源的光刻工艺能够实现的芯片特征尺寸向45nm以下节点延伸。
光刻投影物镜系统波像差是评价光刻机性能的标志性指标之一，它直接影响到光刻机成像质量、光刻分辨率以及特征尺寸均匀性等关键指标。对于工作波长为193nm的高NA投影物镜其波像差应优于10mλ(2nm)，这就要求发展和拥有亚纳米级精度的系统波像差检测技术和装备，精确地测量投影物镜的系统波像差，评估其可能实现的特征线宽，并为投影物镜的进一步超精密装配和修磨提供指导性定量依据，进而对波像差检测方法提出了更高的要求。
目前可用于光刻机投影物镜系统波像差检测的装置包括点衍射干涉仪(Point Diffraction Interferometer)、狭缝衍射干涉仪(Line Diffraction Interferometer)、剪切干涉仪(Lateral Shearing Interferometer)等。带有郎奇光栅(Ronchi)的横向剪切干涉仪是评价和测量光刻投影物镜像差的有效方法已被证明在193nm深紫外波段的光刻检测领域具有良好的表现。横向剪切干涉仪相对于点衍射干涉仪更易于装调及对准并且具有较高的条纹 对比度，可用于大数值孔径光刻物镜的测量，具有很高的检测精度。
由于采用了基于光栅衍射的剪切干涉原理，其特殊的光路结果使得探测器倾斜所导致的像散误差，横向剪切的光路结构所导致的几何慧差以及光栅衍射引入的像差等系统误差对测量精度具有很大的影响，影响了测量的精度。
现有技术虽然也有对系统误差进行标定的方法，例如专利CN102368139B采用了基于光栅衍射的剪切干涉仪测量投影物镜的波像差，通过旋转被测投影物镜的绝对标定方法外加两次轴外点测量，标定干涉仪测量系统的系统误差。但该方法对被测投影物镜在旋转过程中对偏心和倾斜等技术指标都有严格的要求，因此不仅需要承重能力很强的旋转机构，并且该旋转机构还要求极高的定位精度与重复性，这在工程中实现起来十分困难。并且通过旋转被测投影物镜分离系统误差的方法对于使用反射镜和离轴光学元件的高NA投影物镜带有很大的局限性。
发明内容
(一)要解决的技术问题
本发明的目的是提供一种可标定系统误差的系统波像差检测方法，以解决系统误差对系统波像差检测精度的影响问题。
(二)技术方案
本发明提供了一种可标定系统误差的系统波像差检测方法，包括：步骤A：利用剪切干涉检测系统对被测投影物镜进行检测，获得被测投影物镜的系统波像差，所述系统波像差包括被测投影物镜的实际波像差和检测系统的系统误差；步骤B：移除被测投影物镜，获得剪切干涉检测系统的系统误差；以及步骤C：由所述被测投影物镜的系统波像差和剪切干涉检测系统的系统误差，得到被测投影物镜的实际波像差。
优选地，所述剪切干涉检测系统包括：测试光束生成子系统和传感器模块12；所述测试光束生成子系统包括：第二汇聚透镜7；被测投影物镜8位于第二汇聚透镜7和传感器模块12之间，所述被测投影物镜的物方焦平面与第二汇聚透镜的像方焦平面重合；所述第二汇聚透镜发出的测试光束进入被测投影物镜8，所述被测投影物镜的出射光束入射至传感器模块12；在步骤B中，将所述被测投影物镜8从第二汇聚透镜7和传感器模块 12之间移除，以获得剪切干涉检测系统的系统误差。
优选地，所述传感器模块12包括空间滤波器202；所述步骤B包括：子步骤B1：移除所述被测投影物镜8，将所述传感器模块12移动到第二汇聚透镜7下方，所述空间滤波器202与第二汇聚透镜的像方焦平面重合；子步骤B2：获得第一组相移干涉条纹图和第二组相移干涉条纹图；子步骤B3：对所述第一组相移干涉条纹图和第二组相移干涉条纹图进行处理，获得剪切干涉检测系统的系统误差。
优选地，所述传感器模块12还包括：分束装置201、图像传感器11、承载分束装置在二维方向移动的移相装置9和承载空间滤波器在二维方向移动的微动台10，所述分束装置201包括刻线方向相互正交的第一光栅201a和第二光栅201b；所述子步骤B2包括：子分步骤B2a：令所述移相装置9带动分束装置201沿垂直于第一光栅201a刻线方向移动，在衍射光中引入有序相移，令所述微动台10带动空间滤波器202跟随分束装置201移动至与第一光栅匹配的位置，获得垂直于第一光栅201a刻线方向的第一组相移干涉条纹图；子分步骤B2b：令所述移相装置9带动分束装置201沿垂直于第二光栅201b刻线方向移动，在衍射光中引入有序相移，令所述微动台10带动空间滤波器202跟随分束装置201移动至与第二光栅匹配的位置，获得垂直于第二光栅201b刻线方向的第二组相移干涉条纹图。
优选地，在所述子分步骤B2a中，所述测试光束经第一光栅201a后形成衍射光；在所述子分步骤B2b中，所述测试光束经第二光栅201b后形成衍射光；并且，在所述子分步骤B2a和所述子分步骤B2b中，零级以及高级次的衍射光被空间滤波器202截至，±1级衍射光通过空间滤波器的两个窗口并入射至图像传感器11。
优选地，所述子步骤B3包括：对所述第一组相移干涉条纹图和第二组相移干涉条纹图进行位相提取及相位展开，采用微分Zernike多项式进行波面拟合，得到36项Zernike系数表示的系统误差Wsystem。
优选地，所述步骤A包括：子步骤A1：获得第三组相移干涉条纹图和第四组相移干涉条纹图；子步骤A2：对所述第三组相移干涉条纹图和第四组相移干涉条纹图进行处理，获得被测投影物镜的系统波像差。
优选地，所述传感器模块12包括：分束装置201、空间滤波器202、图像传感器11、承载分束装置在二维方向移动的移相装置9和承载空间滤波器在二维方向移动的微动台10，所述分束装置201包括刻线方向相互正交的第一光栅201a和第二光栅201b；所述子步骤A1包括：子分步骤A1a：令所述移相装置9带动分束装置201沿垂直于第一光栅201a刻线方向移动，在衍射光中引入有序相移，令所述微动台10带动空间滤波器202跟随分束装置201移动至与第一光栅匹配的位置，获得垂直于第一光栅201a刻线方向的第三组相移干涉条纹图；子分步骤A1b：令所述移相装置9带动分束装置201沿垂直于第二光栅201b刻线方向移动，在衍射光中引入有序相移，令所述微动台10带动空间滤波器202跟随分束装置201移动至与第二光栅匹配的位置，获得垂直于第二光栅201b刻线方向的第四组相移干涉条纹图。
优选地，在所述子分步骤A1a中，所述被测投影物镜的出射光束经第一光栅201a后形成衍射光；在所述子分步骤A1b中，所述被测投影物镜的出射光束经第二光栅201b后形成衍射光；并且，在所述子分步骤A1a和所述子分步骤A1b中，零级以及高级次的衍射光被空间滤波器202截至，±1级衍射光通过空间滤波器的窗口并入射至图像传感器11。
优选地，所述子步骤A2包括：对所述第三组相移干涉条纹图和第四组相移干涉条纹图进行位相提取及相位展开，采用微分Zernike多项式进行波面拟合，得到36项Zernike多项式系数表示的被测投影物镜的系统波像差W1。
优选地，采用以下公式计算所述系统波像差W1：W1＝Wreal+Wsystem
其中，Wreal表示被测投影物镜的实际波像差，Wsystem表示剪切干涉检测系统的系统误差。
优选地，所述步骤C包括：将所述被测投影物镜的系统波像差与剪切干涉检测系统的系统误差相减，获得被测投影物镜实际波像差。
优选地，所述测试光束生成子系统沿测试光束的传播方向还依次包括：光源1、照明系统2、第一汇聚透镜3、小孔空间滤波器4、准直镜5和反射镜6；其中，所述光源1发射的照明光束依次经过同轴设置的照明系统2、第一汇聚透镜3、小孔空间滤波器4和准直镜5，经反射镜6折转90 度后经第二汇聚透镜7透射生成测试光束。
(三)有益效果
从以上技术方案可以看出，本发明的可标定系统误差的系统波像差检测方法具有下列有益效果：
1)本发明采用的小孔空间滤波器可以起到滤波的作用，可以消除照明系统及第一汇聚透镜所导致的像差，提高了系统波像差的检测精度；
2)空间滤波器使得只有±1级衍射光才能通过空间滤波器中的窗口，零级以及更高级次的衍射光都被空间滤波器截至，从而使得噪声减小并且测量精度获得改善；
3)将被测投影物镜的系统波像差与剪切干涉检测系统的系统误差相减，获得被测投影物镜实际波像差，由于消除了系统误差的影响，从而提高了测量精度，最终获得高精度的投影物镜的系统波像差。
附图说明
附图是用来提供对本发明的进一步理解，并且构成说明书的一部分，与下面的具体实施方式一起用于解释本发明，但并不构成对本发明的限制。在附图中：
图1为本发明实施例的可标定系统误差的系统波像差检测方法的流程图；
图2为本发明实施例检测系统波像差的剪切干涉检测系统示意图；
图3为本发明实施例检测系统误差的剪切干涉检测系统示意图；
图4为本发明实施例分束装置的示意图。
符号说明
1-光源；2-照明系统；3-第一汇聚透镜；4-小孔空间滤波器；5-准直镜；6-反射镜；7-第二汇聚透镜；8-被测投影物镜；9-移相装置；10-微动台；11-图像传感器；12-传感器模块；
201-分束装置；201a-第一光栅；201b-第二光栅；202-空间滤波器。
具体实施方式
为了解决现有干涉测量方法导致测量结果中存在系统误差，影响检测精度的问题，本发明提出一种可标定系统误差的系统波像差检测方法。
为使本发明的目的、技术方案和优点更加清楚明白，以下结合具体实施例，并参照附图，对本发明进一步详细说明。
参见图1，图1示出了本发明实施例的可标定系统误差的系统波像差检测方法的流程图。该系统波像差检测方法包括：
步骤A：利用剪切干涉检测系统对被测投影物镜进行检测，获得被测投影物镜的系统波像差，该系统波像差包括被测投影物镜的实际波像差和检测系统的系统误差。
步骤A中剪切干涉检测系统的结构如图2所示，该检测系统包括：测试光束生成子系统和传感器模块12；测试光束生成子系统包括：光源1、照明系统2、第一汇聚透镜3、小孔空间滤波器4、准直镜5、反射镜6和第二汇聚透镜7。其中，被测投影物镜8位于第二汇聚透镜7和传感器模块12之间，且被测投影物镜8可从所述剪切干涉检测系统中移除。
其中，光源1产生照明光束，光源1、照明系统2、第一汇聚透镜3、小孔空间滤波器4和准直镜5依次同轴设置，反射镜6与光轴呈45度角设置，经反射镜6偏转90度的光轴上依次设置第二汇聚透镜7、被测投影物镜8和传感器模块12。其中，传感器模块12包括分束装置201、空间滤波器202、移相装置9、微动台10和图像传感器11。
光源1可以为ArF准分子激光器、KrF准分子激光器或可见光波段的激光器；照明系统2为扩束透镜组或光束整形器；第一汇聚透镜3与准直镜5的材料为熔石英并镀有光学增透膜；第一汇聚透镜3的像平面与准直镜5的物平面相重合，小孔空间滤波器4位于第一汇聚透镜3和准直镜5的焦点上，小孔空间滤波器4可通过电子束曝光或反应离子束刻蚀方法制备，小孔空间滤波器4的针孔直径小于照明光束的衍射极限分辨率，以起到滤波的作用，消除照明系统2及第一汇聚透镜3所导致的像差，以提高系统波像差的检测精度。
反射镜6与水平方向(光轴)成45°放置并镀有增反膜；第二汇聚透镜7采用物方远心结构，且第二汇聚透镜7的像方焦平面与被测投影物镜8的物方焦平面重合，第二汇聚透镜7的材料为熔石英并镀有增透膜；投影物镜为全透射式投影物镜、折返式投影物镜或者全反射式投影物镜等。
分束装置201采用二元振幅光栅或二元位相光栅，由于系统波像差检 测方法采用剪切干涉原理，获得投影物镜系统波像差需要正交方向上的两次测量，因此分束装置201由刻线方向相互正交、周期以及占空比完全相同的两个光栅-第一光栅201a和第二光栅201b组成，第一光栅201a的刻线沿第一方向(如图4中的x方向)，第二光栅201b的刻线沿与第一方向垂直的第二方向(如图4中的y方向)。
正交放置的空间滤波器202由两个窗口组成，其窗口尺寸与中心距使得当衍射光经过空间滤波器后，只有±1级衍射光才能通过空间滤波器202中的窗口，零级以及更高级次的衍射光都被空间滤波器202截至，从而使得噪声减小并且测量精度获得改善。两个窗口的宽度相等并且满足式(1)：
Figure PCTCN2016101556-appb-000001
式中λ为光源的波长，NAi为被测投影物镜8的像方数值孔径，f为被测投影物镜8出瞳波像差空间频率。
空间滤波器202基底材料为硅或融石英等，在基底材料上沉积铬、镍、钽等抗紫外层材料，并通过电子束曝光或反应离子束刻蚀方法制备所需方形窗口。
移相装置9采用压电陶瓷微位移台，能承载分束装置201在二维方向精确移动，通过推动分束装置201沿垂直于第一光栅201a刻线方向和垂直于第二光栅201b刻线方向移动，从而在衍射光之间引入相移。
在步骤A中，首先，光源1发射照明光束，照明光束进入照明系统2后由照明系统2调节光强分布和照明方式，照明系统的出射光束经第一汇聚透镜3后入射到小孔空间滤波器4，经小孔空间滤波器4后衍射产生理想球面波前，球面波前经准直物镜5后扩束为平行光束入射到反射镜6，平行光束经反射镜6后传播方向折转90度入射到的第二汇聚透镜7。
然后，平行光束经第二汇聚透镜7后入射进被测投影物镜8并充满被测投影物镜8的整个视场，被测投影物镜8的出射光束带有系统波像差信息。
接着，被测投影物镜8的出射光束入射到传感器模块12，经传感器模块12的分束装置201和空间滤波器202后，包含相移的±1级衍射光发生干涉，形成垂直于第一光栅201a刻线方向的第三组相移干涉条纹图和垂 直于第二光栅201b刻线方向的第四组相移干涉条纹图。
上述形成垂直于第一光栅201a刻线方向的第三组相移干涉条纹图和垂直于第二光栅201b刻线方向的第四组相移干涉条纹图的步骤包括：
出射光束入射至第一光栅201a，形成衍射光，令移相装置9带动分束装置201沿垂直于第一光栅201a刻线方向移动，从而在衍射光中引入有序相移，令微动台10带动空间滤波器202跟随分束装置201移动至与第一光栅201a匹配的位置，使得零级以及高级次的衍射光被空间滤波器202截至，只有±1级衍射光能够通过空间滤波器202的的两个窗口并入射至图像传感器11，形成垂直于第一光栅201a刻线方向(Y方向)的第三组相移干涉条纹图；以及
出射光束入射至第二光栅201b，形成衍射光，移相装置9带动分束装置201沿垂直于第二光栅201b刻线方向移动，从而在衍射光中引入有序相移，令微动台10带动空间滤波器202跟随分束装置201移动至与第二光栅201b匹配的位置，使得零级以及高级次的衍射光被空间滤波器202截至，只有±1级衍射光能够通过空间滤波器202的两个窗口并入射至图像传感器11，形成垂直于第二光栅201b刻线方向(X方向)的第四组相移干涉条纹图。
最后，对第三组相移干涉条纹图和第四组相移干涉条纹图进行处理，获得被测投影物镜的系统波像差。
其中，可以利用计算机对垂直于第一光栅201a刻线方向的第三组相移干涉条纹图和垂直于第二光栅201b刻线方向的第四组相移干涉条纹图进行位相提取及相位展开，采用微分Zernike多项式进行波面拟合，得到36项Zernike多项式系数表示的被测投影物镜的系统波像差W1。
其中W1＝Wreal+Wsystem，Wreal表示被测投影物镜的实际波像差，Wsystem表示剪切干涉检测系统的系统误差，该系统误差包括照明系统、汇聚透镜所引入的系统误差Will以及传感器模块所引入的系统误差Wsensor。
步骤B：移除被测投影物镜，获得剪切干涉检测系统的系统误差。
步骤B的剪切干涉检测系统结构如图3所示，其与图2所示结构的区别在于，该检测系统将被测投影物镜8移除，并且传感器模块的空间滤波器202与第二汇聚透镜7的像方焦平面重合。
在步骤B中，首选，移除被测投影物镜8，将传感器模块12运动到第二汇聚透镜7下方，使传感器模块的空间滤波器202与第二汇聚透镜7的像方焦平面重合。
接着，光源1发射照明光束，照明光束进入照明系统2后由照明系统2调节光强分布和照明方式，照明系统的出射光束经第一汇聚透镜3后入射到小孔空间滤波器4，经小孔空间滤波器4后衍射产生理想球面波前，球面波前经准直物镜5后扩束为平行光束入射到反射镜6，平行光束经反射镜6后传播方向折转90度入射到第二汇聚透镜7。
然后，第二汇聚透镜7的出射光束入射到传感器模块12，经传感器模块12的分束装置201和空间滤波器202后，包含相移的±1级衍射光发生干涉，形成垂直于第一光栅201a刻线方向的第一组相移干涉条纹图和垂直于第二光栅201b刻线方向的第二组相移干涉条纹图。
其中，形成垂直于第一光栅201a刻线方向的第一组相移干涉条纹图和垂直于第二光栅201b刻线方向的第二组相移干涉条纹图的具体过程与子步骤A3类似，具体包括：
出射光束入射至第一光栅201a，形成衍射光，令移相装置9带动分束装置201沿垂直于第一光栅201a刻线方向移动，从而在衍射光中引入有序相移，令微动台10带动空间滤波器202跟随分束装置201移动至与第一光栅201a匹配的位置，使得零级以及高级次的衍射光被空间滤波器202截至，只有±1级衍射光能够通过空间滤波器202的两个窗口并入射至图像传感器11，形成垂直于第一光栅201a刻线方向(Y方向)的第一组相移干涉条纹图；以及
出射光束入射至第二光栅201b，形成衍射光，令移相装置9带动分束装置201沿垂直于第二光栅201b刻线方向移动，从而在衍射光中引入有序相移，令微动台10带动空间滤波器202跟随分束装置201移动至与第二光栅201b匹配的位置，使得零级以及高级次的衍射光被空间滤波器202截至，只有±1级衍射光能够通过空间滤波器202的两个窗口并入射至图像传感器11，形成垂直于第二光栅201b刻线方向(X方向)的第二组相移干涉条纹图。
最后，对第一组相移干涉条纹图和第二组相移干涉条纹图进行处理， 获得剪切干涉检测系统的系统误差。
其中，利用计算机对垂直于第一光栅201a刻线方向的第一组相移干涉条纹图和垂直于第二光栅201b刻线方向的第二组相移干涉条纹图进行位相提取及相位展开，采用微分Zernike多项式进行波面拟合，得到36项Zernike系数表示的系统误差W2。由于移除了被测投影物镜8，使得测量结果W2中仅包含照明系统、汇聚透镜所引入的系统误差Will以及传感器模块所引入的系统误差Wsensor，所以移除被测投影物镜后所获得的测量结果W2即可表示为系统误差Wsystem，从而得到由Zernike系数表示的系统误差Wsystem并存储在计算机中。
步骤C：步骤A获得的被测投影物镜的系统波像差减去步骤B获得的剪切干涉检测系统的系统误差，得到被测投影物镜的实际波像差。
将被测投影物镜的系统波像差W1与剪切干涉检测系统的系统误差Wsystem相减，获得被测投影物镜实际波像差Wreal，由于消除了系统误差的影响，从而提高了测量精度，最终获得高精度的投影物镜的系统波像差。
虽然在上述实施例中，先利用剪切干涉检测系统对被测投影物镜进行检测，获得被测投影物镜的系统波像差，再将移除被测投影物镜，获得剪切干涉检测系统的系统误差，但是本发明并不限于此，上述两个步骤的先后顺序可以互换，即本发明也可以先对剪切干涉检测系统进行测量，获得剪切干涉检测系统的系统误差，再将被测投影物镜放置于第二汇聚透镜和传感器模块之间，使被测投影物镜的物方焦平面与第二汇聚透镜的像方焦平面重合，利用剪切干涉检测系统对被测投影物镜进行检测，获得被测投影物镜的系统波像差，同样可以得到被测投影物镜的实际波像差，并且首先对剪切干涉检测系统进行测量，获得剪切干涉检测系统的系统误差后，可以将系统误差作为参数保存，可以对不同类型不同参数的投影物镜进行标定，适用性广，操作方便。
需要说明的是，上述对各元件的定义并不仅限于实施方式中提到的各种具体结构或形状，本领域的普通技术人员可对其进行简单地熟知地替换，例如：
(1)光路中的光学元件还可以采用其他形式，只要可以实现相同功能即可；
以上所述的具体实施例，对本发明的目的、技术方案和有益效果进行了进一步详细说明，所应理解的是，以上所述仅为本发明的具体实施例而已，并不用于限制本发明，凡在本发明的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (13)

  1. 一种可标定系统误差的系统波像差检测方法，其特征在于，包括：
    步骤A：利用剪切干涉检测系统对被测投影物镜进行检测，获得被测投影物镜的系统波像差，所述系统波像差包括被测投影物镜的实际波像差和检测系统的系统误差；
    步骤B：移除被测投影物镜，获得剪切干涉检测系统的系统误差；以及
    步骤C：由所述被测投影物镜的系统波像差和剪切干涉检测系统的系统误差，得到被测投影物镜的实际波像差。
  2. 如权利要求1所述的系统波像差检测方法，其特征在于，所述剪切干涉检测系统包括：测试光束生成子系统和传感器模块(12)；所述测试光束生成子系统包括：第二汇聚透镜(7)；被测投影物镜(8)位于第二汇聚透镜(7)和传感器模块(12)之间，所述被测投影物镜的物方焦平面与第二汇聚透镜的像方焦平面重合；
    所述第二汇聚透镜发出的测试光束进入被测投影物镜(8)，所述被测投影物镜的出射光束入射至传感器模块(12)；
    在步骤B中，将所述被测投影物镜(8)从第二汇聚透镜(7)和传感器模块(12)之间移除，以获得剪切干涉检测系统的系统误差。
  3. 如权利要求2所述的系统波像差检测方法，其特征在于，所述传感器模块(12)包括空间滤波器(202)；
    所述步骤B包括：
    子步骤B1：移除所述被测投影物镜(8)，将所述传感器模块(12)移动到第二汇聚透镜(7)下方，所述空间滤波器(202)与第二汇聚透镜的像方焦平面重合；
    子步骤B2：获得第一组相移干涉条纹图和第二组相移干涉条纹图；
    子步骤B3：对所述第一组相移干涉条纹图和第二组相移干涉条纹图进行处理，获得剪切干涉检测系统的系统误差。
  4. 如权利要求3所述的系统波像差检测方法，其特征在于，所述传感器模块(12)还包括：分束装置(201)、图像传感器(11)、承载分束 装置在二维方向移动的移相装置(9)和承载空间滤波器在二维方向移动的微动台(10)，所述分束装置(201)包括刻线方向相互正交的第一光栅(201a)和第二光栅(201b)；
    所述子步骤B2包括：
    子分步骤B2a：令所述移相装置(9)带动分束装置(201)沿垂直于第一光栅(201a)刻线方向移动，在衍射光中引入有序相移，令所述微动台(10)带动空间滤波器(202)跟随分束装置(201)移动至与第一光栅匹配的位置，获得垂直于第一光栅(201a)刻线方向的第一组相移干涉条纹图；
    子分步骤B2b：令所述移相装置(9)带动分束装置(201)沿垂直于第二光栅(201b)刻线方向移动，在衍射光中引入有序相移，令所述微动台(10)带动空间滤波器(202)跟随分束装置(201)移动至与第二光栅匹配的位置，获得垂直于第二光栅(201b)刻线方向的第二组相移干涉条纹图。
  5. 如权利要求4所述的系统波像差检测方法，其特征在于，在所述子分步骤B2a中，所述测试光束经第一光栅(201a)后形成衍射光；在所述子分步骤B2b中，所述测试光束经第二光栅(201b)后形成衍射光；
    并且，在所述子分步骤B2a和所述子分步骤B2b中，零级以及高级次的衍射光被空间滤波器202截至，±1级衍射光通过空间滤波器的两个窗口并入射至图像传感器(11)。
  6. 如权利要求3所述的系统波像差检测方法，其特征在于，所述子步骤B3包括：
    对所述第一组相移干涉条纹图和第二组相移干涉条纹图进行位相提取及相位展开，采用微分Zernike多项式进行波面拟合，得到36项Zernike系数表示的系统误差Wsystem。
  7. 如权利要求2所述的系统波像差检测方法，其特征在于，所述步骤A包括：
    子步骤A1：获得第三组相移干涉条纹图和第四组相移干涉条纹图；
    子步骤A2：对所述第三组相移干涉条纹图和第四组相移干涉条纹图进行处理，获得被测投影物镜的系统波像差。
  8. 如权利要求7所述的系统波像差检测方法，其特征在于，所述传感器模块(12)包括：分束装置(201)、空间滤波器(202)、图像传感器(11)、承载分束装置在二维方向移动的移相装置(9)和承载空间滤波器在二维方向移动的微动台(10)，所述分束装置(201)包括刻线方向相互正交的第一光栅(201a)和第二光栅(201b)；
    所述子步骤A1包括：
    子分步骤A1a：令所述移相装置(9)带动分束装置(201)沿垂直于第一光栅(201a)刻线方向移动，在衍射光中引入有序相移，令所述微动台(10)带动空间滤波器(202)跟随分束装置(201)移动至与第一光栅匹配的位置，获得垂直于第一光栅(201a)刻线方向的第三组相移干涉条纹图；
    子分步骤A1b：令所述移相装置(9)带动分束装置(201)沿垂直于第二光栅(201b)刻线方向移动，在衍射光中引入有序相移，令所述微动台(10)带动空间滤波器(202)跟随分束装置(201)移动至与第二光栅匹配的位置，获得垂直于第二光栅(201b)刻线方向的第四组相移干涉条纹图。
  9. 如权利要求8所述的系统波像差检测方法，其特征在于，在所述子分步骤A1a中，所述被测投影物镜的出射光束经第一光栅(201a)后形成衍射光；在所述子分步骤A1b中，所述被测投影物镜的出射光束经第二光栅(201b)后形成衍射光；
    并且，在所述子分步骤A1a和所述子分步骤A1b中，零级以及高级次的衍射光被空间滤波器(202)截至，±1级衍射光通过空间滤波器的窗口并入射至图像传感器(11)。
  10. 如权利要求7所述的系统波像差检测方法，其特征在于，所述子步骤A2包括：
    对所述第三组相移干涉条纹图和第四组相移干涉条纹图进行位相提取及相位展开，采用微分Zernike多项式进行波面拟合，得到36项Zernike多项式系数表示的被测投影物镜的系统波像差W1。
  11. 如权利要求10所述的系统波像差检测方法，其特征在于，采用以下公式计算所述系统波像差W1：
    W1＝Wreal+Wsystem
    其中，Wreal表示被测投影物镜的实际波像差，Wsystem表示剪切干涉检测系统的系统误差。
  12. 如权利要求1所述的系统波像差检测方法，其特征在于，所述步骤C包括：将所述被测投影物镜的系统波像差与剪切干涉检测系统的系统误差相减，获得被测投影物镜实际波像差。
  13. 如权利要求2所述的系统波像差检测方法，其特征在于，所述测试光束生成子系统沿测试光束的传播方向还依次包括：光源(1)、照明系统(2)、第一汇聚透镜(3)、小孔空间滤波器(4)、准直镜(5)和反射镜(6)；
    其中，所述光源(1)发射的照明光束依次经过同轴设置的照明系统(2)、第一汇聚透镜(3)、小孔空间滤波器(4)和准直镜(5)，经反射镜(6)折转90度后经第二汇聚透镜(7)透射生成测试光束。
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