WO2023216545A1 - 光刻机光栅六自由度位移测量系统 - Google Patents

光刻机光栅六自由度位移测量系统 Download PDF

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WO2023216545A1
WO2023216545A1 PCT/CN2022/132836 CN2022132836W WO2023216545A1 WO 2023216545 A1 WO2023216545 A1 WO 2023216545A1 CN 2022132836 W CN2022132836 W CN 2022132836W WO 2023216545 A1 WO2023216545 A1 WO 2023216545A1
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grating
mounting plate
degree
measurement
detector
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PCT/CN2022/132836
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English (en)
French (fr)
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王磊杰
朱煜
张晏福
张鸣
叶伟楠
成荣
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清华大学
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/03—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness by measuring coordinates of points

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  • the invention belongs to the technical field of lithography machines, and specifically relates to a six-degree-of-freedom displacement measurement system for gratings in lithography machines.
  • Ultra-precision displacement measurement technology is the basis of modern ultra-precision machining, which determines the processing accuracy and manufacturing level of products. It occupies an important position in many engineering fields, such as in the field of IC equipment manufacturing.
  • Grating measurement is one of the few optical precision displacement measurement methods that can achieve nanoscale micro-displacement measurement. It is also the most widely used displacement measurement technology in precision displacement measurement systems.
  • using a grating with a certain smaller grating pitch can achieve nanometer-level measurement accuracy.
  • Using a grating with a certain large size can achieve a large measurement range.
  • high-dimensional precision can be achieved. Measure the effect.
  • the grating measurement method uses the grating pitch as the measurement benchmark. It has the advantages of high precision, not susceptible to environmental interference, small size, and low cost. Its value is increasingly highlighted in modern precision measurement technology.
  • the laser interferometer uses a laser interferometer to measure the relative displacement information of the projection objective lens/alignment sensor in the lithography machine.
  • the laser interferometer is sensitive to environmental temperature, environmental humidity and other factors. When the environmental temperature or humidity changes, When used, it will have a serious impact on the wavelength and refractive index of the laser light source.
  • the laser interferometer uses the wavelength of the laser as the measurement benchmark, which will seriously affect the measurement accuracy. Therefore, using a laser interferometer as a measuring instrument cannot meet the required measurement accuracy requirements;
  • a grating interferometer is used to measure the relative displacement information of the projection objective lens/alignment sensor of the lithography machine, but it only realizes the displacement measurement function of the two degrees of freedom of the alignment sensor of the lithography machine and the three freedoms of the projection objective lens of the lithography machine.
  • the requirements for the measurement accuracy of lithography machines are getting higher and higher. Displacement measurement with a low degree of freedom is difficult to meet the needs of lithography machine measurement technology.
  • the present invention provides a six-degree-of-freedom displacement measurement system for the grating of the lithography machine.
  • the specific technical solution is as follows:
  • a six-degree-of-freedom displacement measurement system for photolithography machine gratings including a preprocessing position measurement subsystem and an exposure position measurement subsystem.
  • the preprocessing position measurement subsystem includes a preprocessing position grating mounting plate
  • the exposure position measurement subsystem includes an exposure position grating. mounting plate, and the preprocessing position grating mounting plate and the exposure position grating mounting plate are spaced apart below the main substrate in a direction parallel to the surface of the main substrate, and the preprocessing position grating mounting plate, the exposure position grating mounting plate and the lithography machine Rack fixed connection,
  • the pretreatment position grating installation plate and the exposure position grating installation plate are provided with layout holes.
  • Both the pretreatment position measurement subsystem and the exposure position measurement subsystem include at least three detectors, and the at least three detectors are spaced apart
  • the measurement points are set in the layout holes, and the two-degree-of-freedom displacement of each measurement point is obtained through the detector to form a six-degree-of-freedom solution equation, so as to obtain the six-degree-of-freedom of the pre-processing position grating mounting plate and the exposure position grating mounting plate respectively. Displacement.
  • the upper surface of the plate body is provided with a groove, and the arrangement hole penetrates the plate body in the groove.
  • the arrangement hole is a square hole.
  • Each detector includes a reading head and a scale grating, and the preprocessing position In the measurement subsystem, the reading head and the scale grating are installed on the preprocessing position grating mounting plate and the alignment sensor respectively, and all scale grating planes are arranged along one of the diagonal direction and the side length direction of the layout hole. ;
  • the reading head and the scale grating are respectively installed on the exposure position grating mounting plate and the projection objective lens, and all scale grating planes are arranged along one of the diagonal direction and the side length direction of the arrangement hole. .
  • the reading head and the scale grating are installed on the preprocessing position grating installation plate with the groove bottom plane as the installation reference;
  • the reading head and scale grating are installed on the exposure position grating mounting plate with the bottom plane of the groove as the installation reference.
  • it also includes a laser source, a fiber optic beam splitter and an optical fiber.
  • the optical fiber is connected between the laser source and the fiber optic beam splitter, between the fiber optic beam splitter and the detector, and between the detector and the electronic counting module. time, and single-mode optical fiber is used for transmission between the laser source and the detector, and multi-mode optical fiber is used for transmission between the detector and the electronic counting module.
  • the laser source is a dual-frequency laser, used to emit two laser beams with frequency differences.
  • the two laser beams are decomposed into 6 laser beams through a fiber beam splitter, and each two laser beams are transmitted to a detector through optical fibers. .
  • the detector is a grating interferometer or a grating encoder, and its scale grating is a plane reflection/diffraction two-dimensional grating.
  • the preprocessing position grating mounting plate and the exposure position grating mounting plate are respectively connected to the main substrate through flexible blocks.
  • the measurement points are three corner points of the holes.
  • the laser also emits a laser signal with the same frequency as the frequency difference and transmits it to the phase card component of the electronic counting module as an external reference signal.
  • Each two-channel laser serves as reference light and measurement light and transmits it to the reading head of a detector for measurement.
  • the diffracted light is combined with the reference light to generate a measurement signal.
  • the measurement signal is transmitted to the phase card component through the optical fiber.
  • the phase card component solves the phase difference between the measurement signal and the external reference signal, and we will get The phase difference information is input to the solution card for displacement calculation and the displacement measurement value is obtained.
  • the main substrate has a through hole corresponding to the projection objective lens and the alignment sensor, the projection objective lens is fixed above the corresponding through hole, and the alignment sensor is fixed at the center of the corresponding through hole.
  • the lithography machine grating six-degree-of-freedom displacement measurement system of the present invention can conveniently set up two sets of detectors by arranging the layout holes of the grating mounting plate at the preprocessing position and the grating mounting plate at the exposure position.
  • the displacement measurement system can detect the change in posture information, and then respond accordingly in other subsystems of the lithography machine for position compensation, thereby effectively suppressing or mitigating the vibration of the lithography machine, etc. Factors causing the problem of changes in the spatial posture of the projection objective relative to the grating mounting plate.
  • Figure 1 is a schematic diagram of the general assembly of a grating six-degree-of-freedom displacement measurement system for a photolithography machine provided by an embodiment of the present invention
  • Figure 2 is a schematic diagram of the pre-processing position grating mounting plate and the exposure position grating mounting plate of the lithography machine grating six-degree-of-freedom displacement measurement system provided by the embodiment of the present invention
  • Figure 3 is a schematic diagram of the spatial positions of the grating mounting plate and the main substrate of the grating six-degree-of-freedom displacement measurement system of the photolithography machine provided by the embodiment of the present invention
  • FIG. 4 is a schematic diagram of the spatial positions of the projection objective lens, alignment sensor and main substrate of the grating six-degree-of-freedom displacement measurement system of the lithography machine provided by an embodiment of the present invention.
  • Figure 5-1 is a schematic diagram showing the distribution of the preprocessing bit measurement subsystem on the horizontal plane of the preprocessing bit grating mounting plate of the lithography machine grating six-degree-of-freedom displacement measurement system provided by the embodiment of the present invention
  • Figure 5-2 is a schematic diagram of the spatial distribution of the relative alignment sensor displacement measurement system of the grating mounting plate of the lithography machine grating six-degree-of-freedom displacement measurement system provided by the embodiment of the present invention
  • Figure 6 is a schematic diagram of the detector composition and measurement direction of the six-degree-of-freedom displacement measurement system for gratings in lithography machines provided by an embodiment of the present invention
  • Figure 7 is a schematic diagram of the detector distribution in which the plane direction of the scale grating is 90 degrees to the x-axis direction of the six-degree-of-freedom displacement measurement system for gratings of a lithography machine provided by an embodiment of the present invention
  • Figure 8 is a schematic diagram of the detector distribution in which the scale grating plane direction and the y-axis direction are 90 degrees in the six-degree-of-freedom displacement measurement system of the photolithography machine grating provided by the embodiment of the present invention
  • Figure 9 is a schematic diagram of the spatial distribution of the grating mounting plate relative to the projection objective lens displacement measurement system of the lithography machine grating six-degree-of-freedom displacement measurement system provided by the embodiment of the present invention.
  • Icon 110-pretreatment position grating mounting plate; 1101-circular groove; 1102-arrangement hole; 120-exposure position grating mounting plate; 201-detector; 300-main substrate; 410-alignment sensor; 420-projection Objective lens; 500-scale grating; 501-laser source; 502-fiber beam splitter; 503-fiber; 504-electronic counting module.
  • the six-degree-of-freedom displacement measurement system of the lithography machine grating in this embodiment can use two sets of detectors to measure six sets of displacement parameters of the lithography machine grating mounting plate relative to the projection objective lens/alignment sensor, and then perform six-degree-of-freedom displacement calculations.
  • the spatial posture of the grating mounting plate relative to the projection objective/alignment sensor is obtained, which can be used to suppress or alleviate the impact of the vibration of the lithography machine platform on the relative posture of the grating mounting plate relative to the projection objective/alignment sensor.
  • the lithography machine grating six-degree-of-freedom displacement measurement system includes a laser source 501, a fiber splitter 502, an optical fiber 503, a preprocessing position measurement subsystem, an exposure position measurement subsystem, and an electronic counting module 504.
  • optical fibers 503 are connected between them.
  • the laser source 501 is used to provide input light with a specific wavelength and specific power.
  • the optical fiber beam splitter 502 is used to divide the single input light emitted by the laser source into multiple input lights.
  • the optical fiber splitter divides the input light into multiple input lights and then inputs the preprocessing position measurement subsystem and the exposure position measurement subsystem.
  • Both the preprocessing position measurement subsystem and the exposure position measurement subsystem include multiple detectors 201 .
  • the optical fiber 503 is used to input multi-channel input light to the reading head of each detector 201 and transmit the return light signal to the electronic counting module 504.
  • the pretreatment position measurement subsystem includes a pretreatment position grating installation plate 110
  • the exposure position measurement subsystem includes an exposure position grating installation plate 120
  • the pretreatment position grating installation plate 110, the exposure position grating installation plate 110, and the exposure position grating installation plate 120 are spaced apart below the main substrate 300 along a first direction (that is, in a direction parallel to the board surface of the main substrate 300).
  • the first direction corresponds to the x-axis in FIG. 3 .
  • the main substrate 300, the pre-processing position grating mounting plate 110 and the exposure position grating mounting plate 120 are spaced apart along a second direction (that is, a direction perpendicular to the surface of the main substrate).
  • the second direction corresponds to the drawing.
  • the first direction and the second direction are perpendicular to each other.
  • the pre-processing position grating mounting plate 110 and the exposure position grating mounting plate 120 may be respectively connected to the main substrate 300 through flexible blocks (not shown in the figure).
  • the projection objective lens 420 of the lithography machine is fixed directly above the exposure position grating mounting plate 120 and is spaced apart from the exposure position grating mounting plate 120 along the second direction.
  • the alignment sensor 410 of the lithography machine is fixed on the preprocessing position. at the center of the grating mounting plate 110 .
  • the main substrate 300 has a through hole for the projection objective lens 420 and the alignment sensor 410 to transmit signals.
  • the preprocessing position grating mounting plate 110 and the exposure position grating mounting plate 120 are installed on the lithography machine frame.
  • This application is to measure the displacement of the grating mounting plate 110 at the preprocessing position relative to the alignment sensor 410 and the displacement of the grating mounting plate 120 at the exposure position relative to the projection objective lens 420 under the influence of vibration caused by the operation of the lithography machine.
  • the preprocessing position measurement subsystem and the exposure position measurement subsystem are respectively installed on the exposure position grating installation plate and the preprocessing position grating installation plate.
  • Each measurement subsystem includes three detectors 201, and each detector All have the measurement function of two degrees of freedom, which are the plane displacement parallel to the upper surface of the grating mounting plate and the displacement perpendicular to the upper surface direction of the grating mounting plate. Of course, it may not be vertical.
  • the preprocessing position grating installation plate 110 and the exposure position grating installation plate 12 have the same structure. Only the preprocessing position grating installation plate 110 will be described below. As shown in Figure 2, the preprocessing position grating installation plate 110 is the plate body, and the preprocessing position grating installation plate 110 is the plate body. At the center of the grating installation plate 110, there is a circular groove 1101 on the plate facing the alignment sensor 410, and there is a layout hole 1102 penetrating the plate in the circular groove 1101. This spatial structure is conducive to the detector. arrangement, and the bottom plane of the circular groove can provide an installation reference for the detector.
  • the six-degree-of-freedom displacement measurement system of the relative alignment sensor 410 of the preprocessing bit grating mounting plate 110 includes three detectors, and the three detectors are spaced apart in the preprocessing position.
  • the processing position grating installation plate 110 is arranged at three diagonal corners of the arrangement hole (but is not limited to the diagonal corners of the arrangement hole, and the detector can be arranged at any position within the arrangement hole under space requirements).
  • any detector can be a grating interferometer or a grating encoder, including a reading head and a scale grating.
  • the reading head and the scale grating are respectively installed on the preprocessing bit grating mounting plate and the alignment sensor.
  • the reading head and the scale grating are installed on the exposure position grating mounting plate and the projection objective lens respectively.
  • the meaning of separate installation means that the reading head is installed on the preprocessing position grating installation plate, then the scale grating is installed on the alignment sensor, and the reading head is installed on the alignment sensor, then the scale grating is installed on Preprocessing bit grating mounting plate.
  • the reading head of the detector is fixed on the pre-processing position grating mounting plate 110 through the reading head mounting base, and the bottom plane of the circular groove of the pre-processing position grating mounting plate 110 is used as the installation reference.
  • the detector's scale grating is fixedly connected to the alignment sensor through the scale grating mounting seat, the scale grating plane is vertical to the bottom plane of the circular groove, and the scale grating plane is at an angle of 45 degrees to the first direction (i.e., the x-axis direction) , which cooperates with the detector readhead to provide a measurement reference.
  • the scale grating plane of one detector and the scale grating planes of the other two detectors are respectively at an angle of plus or minus 45 degrees with the first direction.
  • the scale grating plane of one detector and the scale grating plane of the other two detectors are along different diagonal directions of the arrangement holes. This is just an example, and the degree of freedom measurement can be achieved if the scale grating plane is at other angles to the first direction.
  • the installation positions of the scale grating and the reading head of the detector in the present invention can also be interchanged, that is, the scale grating of the detector is fixed on the pre-processing position grating installation plate 110 through the scale mounting seat, so that the pre-processing position grating installation plate 110 is circular
  • the bottom plane of the groove is the installation datum.
  • the plane of the scale grating is perpendicular to the bottom plane of the groove.
  • the plane of the scale grating is at an angle of 45 degrees to the first direction (i.e., the x-axis direction).
  • the reading head of the detector is connected to the opposite side through the reading head mounting base.
  • the quasi-sensor is fixed and cooperates with the detector scale grating to provide a measurement reference.
  • the plane displacement of the upper surface of the grating mounting plate refers to the displacement measurement perpendicular to the scale grating plane, that is, the measurement direction 1 that is at an angle of 45 degrees to the positive x-axis coordinate.
  • the displacement perpendicular to the surface direction of the grating mounting plate refers to the displacement measurement parallel to the grating plane and perpendicular to the grating line, that is, the measurement direction 2 that coincides with the z-axis coordinate.
  • each set of detectors can obtain six displacement measurements, form a six-degree-of-freedom solution equation, and then solve the six-degree-of-freedom displacement, and obtain the projection objective lens or alignment sensor
  • the spatial posture relative to the grating mounting plate can also be realized by forming any other angle between the detector scale grating plane and the first direction (x-axis direction), and is not limited to the embodiments provided by the present invention.
  • the read head may include a lens group that generates an interference signal and an incident/return light signal receiver.
  • the optical lens group is used to generate laser interference signals
  • the incident light/return light signal receiver is used to provide input signals and receive output interference signals.
  • the scale grating is a plane reflection/diffraction two-dimensional grating, which is the measurement reference of a grating interferometer or a grating encoder.
  • the reading head receives the incident light signal transmitted by the optical fiber 503 through the incident light signal receiver.
  • the incident light signal passes through the lens group of the reading head and the scale grating 500 to generate a return light signal containing displacement information, and uses the optical fiber 503 to transmit the return light signal. to electronic counting module 504.
  • the electronic counting module 504 is used to process the light return signal containing displacement information.
  • the six-degree-of-freedom displacement measurement system of the exposure position grating mounting plate 120 relative to the projection objective 420 also includes three detectors, and the three detectors are spaced apart on the exposure position grating mounting plate. 120 layout holes in three diagonal corners.
  • the reading head of the detector is fixed on the exposure grating mounting plate 120 through the reading head mounting base.
  • the bottom plane of the circular groove of the exposure grating mounting plate 120 is used as the installation reference.
  • the scale grating of the detector passes through the scale.
  • the grating mounting base is fixedly connected to the projection objective lens 420.
  • the scale grating plane remains perpendicular to the bottom plane of the circular groove and the scale grating plane forms an angle of 45 degrees with the first direction, that is, the x-axis direction, and cooperates with the detector reading head to provide measurement benchmark.
  • the installation positions of the scale grating and the reading head of the detector in the present invention can also be interchanged, that is, the scale grating of the detector is fixed on the exposure position grating mounting plate 120 through the scale mounting seat, and the exposure position grating mounting plate 120 has a circular groove.
  • the bottom plane is the installation datum.
  • the scale grating plane is perpendicular to the groove bottom plane and the scale grating plane forms an angle of 45 degrees with the first direction, that is, the x-axis direction.
  • the reading head of the detector is fixed to the projection objective lens 420 through the reading head mounting base. Connected, it cooperates with the detector scale grating to provide a measurement reference.
  • the laser source can be a dual-frequency laser, providing two laser beams with a stable frequency difference to the measurement subsystem.
  • the two lasers pass through the optical fiber 503 and the optical fiber splitter 502 and are divided into 6 lasers equally.
  • Each two lasers are used as reference light and measurement light and are transmitted to the reading head of a detector.
  • the measurement light passes through the measurement path and is incident on the grating to form
  • the diffracted light is combined with the reference light to generate a measurement signal. Because there is relative displacement between the grating and the detector reading head, the grating Doppler effect will occur, and the frequency and phase of the measurement signal will change accordingly.
  • the light of the reference path does not pass through the grating, and the phase and frequency do not change.
  • the laser also emits an optical signal with the same frequency as the frequency difference and transmits it to the phase card component of the electronic counting module as an external reference signal.
  • the measurement signal from the detector reading head is transmitted to the phase card component through multi-mode optical fiber.
  • the phase card component solves the phase difference between the measurement signal and the reference signal, and inputs the obtained phase difference information into the solution card for displacement calculation and conversion. is the displacement measurement value.
  • the displacement measurement system can detect the change in posture information, and then respond accordingly in other subsystems of the lithography machine for position compensation, thus Effectively suppress or alleviate the problem of changes in the spatial posture of the projection objective lens relative to the grating mounting plate caused by factors such as vibration of the lithography machine.

Abstract

一种光刻机光栅六自由度位移测量系统，用于测量光栅安装板（110、120）相对于光刻机投影物镜（420）和对准传感器（410）的空间位姿，包括两个位移测量分系统，每个测量分系统包含三个探测器（201）并且每个探测器（201）具备二自由度的测量功能。通过设置预处理位光栅安装板（110）、曝光位光栅安装板（120）的布置孔（1102），可以便利的设置两组探测器（201），能够准确快捷的获得六自由度位移，可以解决因光刻机振动、环境影响等因素引起光栅安装板（110、120）相对投影物镜（420）和对准传感器（410）的空间位姿变化的难题。

Description

光刻机光栅六自由度位移测量系统
本申请要求于2022年05月10日提交中国专利局、申请号为202210502276.4，发明名称为“光刻机光栅六自由度位移测量系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明属于光刻机技术领域，具体说，涉及光刻机光栅六自由度位移测量系统。
背景技术
超精密位移测量技术是现代超精密加工的基础，决定着产品的加工精度和制造水平，在许多工程领域中占据着重要地位，比如在IC装备制造领域。光栅测量是少数能达到纳米级微位移测量的光学精密位移测量方法，同时也是在精密位移测量系统中应用最广泛的一种位移测量技术。在光栅位移测量系统中，使用一定较小栅距的光栅可以达到纳米级别的测量精度，使用一定大尺寸的光栅可以实现大量程的测量范围，通过相互配合不同维度的光栅可以实现高维度的精密测量效果。光栅测量法以光栅的栅距作为测量基准，具有精度高、不易受环境干扰、体积小、成本较低等优点，在现代精密测量技术中愈加凸显其价值。
现有技术中有利用激光干涉仪测量光刻机内投影物镜/对准传感器的相对位移信息的测量系统，但激光干涉仪对环境温度、环境湿度等因素比较敏感，当环境的温度或湿度变化时，会对激光光源的波长和折射率产生严重影响，激光干涉仪以激光的波长作为测量基准，进而严重影响测量精度。因此，采用激光干涉仪作为测量仪达不到所需的测量精度要求；
在现有技术中存在利用光栅干涉仪测量光刻机投影物镜/对准传感器的相对位移信息，但仅实现光刻机对准传感器二自由度的位移测量功能以及光 刻机投影物镜的三自由度的空间位置测量功能，随着光刻技术的发展，对光刻机测量精度要求越来越高，低自由度的位移测量难以满足光刻机测量技术需求。
发明内容
为抑制或缓解光刻机振动对光栅安装板相对投影物镜/对准传感器相对位姿的影响，本发明提供一种光刻机光栅六自由度位移测量系统，具体技术方案如下：
一种光刻机光栅六自由度位移测量系统，包括预处理位测量分系统和曝光位测量分系统，预处理位测量分系统包括预处理位光栅安装板，曝光位测量分系统包括曝光位光栅安装板，并且预处理位光栅安装板、曝光位光栅安装板沿平行于主基板板面的方向间隔布置在主基板下方，所述预处理位光栅安装板、曝光位光栅安装板与光刻机机架固定连接，
预处理位光栅安装板、曝光位光栅安装板的板体上都设置有布置孔，预处理位测量分系统和曝光位测量分系统都包括至少三个探测器，所述至少三个探测器间隔设置在布置孔内的测量点，通过探测器获得各测量点的二自由度位移组建六自由度解算方程，从而分别解算获得预处理位光栅安装板、曝光位光栅安装板的六自由度位移。
可选的，板体的上表面设置有凹槽，布置孔在所述凹槽内穿透板体，所述布置孔为方形孔，每一探测器都包含读数头和标尺光栅，预处理位测量分系统中，所述读数头和标尺光栅分别安装在预处理位光栅安装板和对准传感器上，且所有标尺光栅平面都沿布置孔对角线方向和边长方向中的一种方向设置；
曝光位测量分系统中，所述读数头和标尺光栅分别安装在曝光位光栅安装板和投影物镜上，且所有标尺光栅平面都沿布置孔对角线方向和边长方向中的一种方向设置。
可选的，预处理位测量分系统中，读数头和标尺光栅都是以凹槽底平面为安装基准的形式安装在预处理位光栅安装板上；
曝光位测量分系统中，读数头和标尺光栅都是以凹槽底平面为安装基准的形式安装在曝光位光栅安装板上。
可选的，还包括；激光源、光纤分束器和光纤，所述光纤连接于激光源与光纤分束器之间，光纤分束器与探测器之间，以及探测器与电子计数模块之间，并且，激光源到探测器之间采用单模光纤传输，探测器到电子计数模块之间采用多模光纤传输。
可选的，所述激光源为双频激光器，用于发出具有频差的两束激光，两束激光经过光纤分束器都分解为6路激光，每两路激光通过光纤传输至一个探测器。
可选的，所述探测器为光栅干涉仪或者光栅编码器，其标尺光栅是平面反射/衍射型二维光栅。
可选的，预处理位光栅安装板和曝光位光栅安装板是分别通过柔性块与主基板相连。
可选的，所述测量点为布置孔的三个角点处。
可选的，激光器还发射一路与频差相等频率的激光信号传输至电子计数模块的相位卡部件作为外部参考信号，每两路激光作为参考光和测量光传输至一个探测器的读数头，测量光经过测量路会入射标尺光栅形成衍射光，衍 射光与参考光合束产生测量信号，测量信号经光纤传输至相位卡部件，相位卡部件求解测量信号与外部参考信号之间的相位差，将得到的相位差信息输入到解算卡进行位移解算，获得位移测量值。
可选的，所述主基板具有与投影物镜、对准传感器对应的通孔，所述投影物镜固定在对应通孔上方，所述对准传感器固定在对应通孔中心。
本发明的光刻机光栅六自由度位移测量系统，通过设置预处理位光栅安装板、曝光位光栅安装板的布置孔，可以便利的设置两组探测器，当光栅安装板相对投影物镜/对准传感器发生任何微小的空间位姿变化，该位移测量系统都能检测到位姿信息变化，进而在光刻机其他分系统中可以作出相应反应进行位置补偿，从而有效抑制或缓解光刻机振动等因素引起投影物镜相对光栅安装板的空间位姿变化的难题。
附图说明
图1为本发明实施例提供的光刻机光栅六自由度位移测量系统的总装示意图；
图2为本发明实施例提供的光刻机光栅六自由度位移测量系统的预处理位光栅安装板和曝光位光栅安装板示意图；
图3为本发明实施例提供的光刻机光栅六自由度位移测量系统的光栅安装板与主基板的空间位置示意图；
图4为本发明实施例提供的光刻机光栅六自由度位移测量系统的投影物镜和对准传感器与主基板的空间位置示意图。
图5-1为本发明实施例提供的光刻机光栅六自由度位移测量系统的预处理位测量分系统在预处理位光栅安装板水平面分布示意图；
图5-2为本发明实施例提供的光刻机光栅六自由度位移测量系统的光栅安装板相对对准传感器位移测量系统空间分布示意图；
图6为本发明实施例提供的光刻机光栅六自由度位移测量系统的探测器组成及测量方向示意图；
图7为本发明实施例提供的光刻机光栅六自由度位移测量系统的标尺光栅平面方向与x轴方向呈90度的探测器分布示意图；
图8为本发明实施例提供的光刻机光栅六自由度位移测量系统的标尺光栅平面方向与y轴方向呈90度的探测器分布示意图；
图9为本发明实施例提供的光刻机光栅六自由度位移测量系统的光栅安装板相对投影物镜位移测量系统空间分布示意图；
图标：110-预处理位光栅安装板；1101-圆形凹槽；1102-布置孔；120-曝光位光栅安装板；201-探测器；300-主基板；410-对准传感器；420-投影物镜；500-标尺光栅；501-激光源；502-光纤分束器；503-光纤；504-电子计数模块。
具体实施方式
下面将结合附图对本发明的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本实施例的光刻机光栅六自由度位移测量系统，利用两组探测器能够测量光刻机光栅安装板分别相对投影物镜/对准传感器的六组位移参数，进而进行六自由度位移解算求得光栅安装板相对投影物镜/对准传感器的空间位姿，从而可以用于抑制或缓解光刻机平台振动对光栅安装板相对投影物镜/对准传感器相对位姿的影响。
如图1所示，该光刻机光栅六自由度位移测量系统，包括激光源501、光纤分束器502、光纤503、预处理位测量分系统和曝光位测量分系统、电子计数模块504。
激光源501与光纤分束器502之间，光纤分束器502与预处理位测量分系统和曝光位测量分系统之间，预处理位测量分系统、曝光位测量分系统与电子计数模块504之间都连接有光纤503。
其中，激光源501用于提供特定波长特定功率的输入光。
其中，光纤分束器502用于将激光源发出的单路输入光分成多路输入光，经光纤分束器分为多路输入光后输入预处理位测量分系统和曝光位测量分系统。预处理位测量分系统和曝光位测量分系统都包含有多个探测器201。
其中，光纤503用于将多路输入光输入到各探测器201的读数头，并将回光信号传输至电子计数模块504。
如图2、图3所示，预处理位测量分系统包括预处理位光栅安装板110，曝光位测量分系统包括曝光位光栅安装板120，并且预处理位光栅安装板110、曝光位光栅安装板120沿第一方向(即沿平行于主基板300板面的方向)间隔分布在主基板300下方，所述第一方向对应附图3中x轴。所述主基板300与所述预处理位光栅安装板110和曝光位光栅安装板120都是沿第二方向(即垂直于主基板板面的方向)间隔分布，所述第二方向对应附图3中的z轴方向，第一方向和第二方向相互垂直。预处理位光栅安装板110和曝光位光栅安装板120可以是分别通过柔性块(图中未示出)与主基板300相连。
如图4所示，光刻机的投影物镜420固定在曝光位光栅安装板120正上方，与曝光位光栅安装板120沿第二方向间隔设置，光刻机的对准传感器410固定在预处理位光栅安装板110的中心位置处。所述主基板300具有供投影物镜420、对准传感器410发射信号穿过的通孔。预处理位光栅安装板110、曝光位光栅安装板120安装在光刻机机架上。本申请就是测量在在光刻机运行中带来振动的影响下，预处理位光栅安装板110相对于对准传感器410的位移，曝光位光栅安装板120相对于投影物镜420的位移。
所述预处理位测量分系统和曝光位测量分系统分别对应设置在曝光位光栅安装板和预处理位光栅安装板上，每个测量分系统都包含有三个探测器201，并且每个探测器都具备二自由度的测量功能，分别为平行于所述光栅安装板上表面的平面位移和垂直于所述光栅安装板上表面方向的位移，当然也可以不是垂直的。
预处理位光栅安装板110、曝光位光栅安装板12的结构相同，下面仅以预处理位光栅安装板110说明，如图2所示，预处理位光栅安装板110为板体，预处理位光栅安装板110中心处，在面向对准传感器410的板面上有一 个圆形凹槽1101，且圆形凹槽1101内有一个穿透板面的布置孔1102，该空间结构有利于探测器的布置，并且圆形凹槽底平面能够为探测器提供安装基准。
如图5-1,5-2所示，本实施例中预处理位光栅安装板110相对对准传感器410的六自由度位移测量系统中包括三个探测器，三个探测器间隔设置在预处理位光栅安装板110布置孔的三个对角处(但不局限在布置孔的对角处，在空间需求下探测器可以布置在布置孔内的任意位置)。
在本发明实施例中，任一探测器可以为光栅干涉仪或光栅编码器，包含读数头和标尺光栅，读数头和标尺光栅分别安装在预处理位光栅安装板和对准传感器上，所述读数头和标尺光栅分别安装在曝光位光栅安装板和投影物镜上。预处理位光栅安装板为例，分别安装的含义是指读数头安装在预处理位光栅安装板，则标尺光栅安装在对准传感器上，读数头安装在对准传感器上，则标尺光栅安装在预处理位光栅安装板上。
如图5-1,5-2所示，探测器的读数头通过读数头安装座固定在预处理位光栅安装板110上，以预处理位光栅安装板110圆形凹槽底平面为安装基准，探测器的标尺光栅通过标尺光栅安装座与对准传感器固连，标尺光栅平面与圆形凹槽底平面保持垂直，并且标尺光栅平面与第一方向(即x轴方向)呈45度夹角，与探测器读数头相互配合以提供测量基准。具体的，一个探测器的标尺光栅平面与另两个探测器的标尺光栅平面分别与第一方向呈正负45度夹角。或者说，一个探测器的标尺光栅平面与另两个探测器的标尺光栅平面分别沿布置孔不同的对角线方向。这只是示例性的，标尺光栅平面与第一方向呈其他角度一样可以实现自由度测量。
本发明中的探测器的标尺光栅和读数头安装位置还可以互换，即探测器的标尺光栅通过标尺安装座固定在预处理位光栅安装板110上，以预处理位光栅安装板110圆形凹槽底平面为安装基准，标尺光栅平面与凹槽底平面保持垂直并且标尺光栅平面与第一方向(即x轴方向)呈45度夹角，探测器的读数头通过读数头安装座与对准传感器固连，与探测器标尺光栅相互配合以提供测量基准。
在这种安装角度下，如图6所示，光栅安装板上表面的平面位移是指垂直于所述标尺光栅平面的位移测量，即与正向x轴坐标呈45度夹角的测量方向1；所述垂直于光栅安装板上表面方向的位移是指平行于光栅平面且垂直栅线的位移测量，即与z轴坐标重合的测量方向2。
不过，除上述的探测器在光栅安装板空间分布方案，还可以是如图7和图8所示，探测器的标尺光栅平面(图中粗线条)与第一方向(x轴方向)呈90度夹角或0度夹角(即平行)，每组探测器都能获得六个位移测量，将其组建六自由度解算方程，进而解算出六自由度位移，得出投影物镜或对准传感器相对光栅安装板的空间位姿。类似的，探测器标尺光栅平面与第一方向(x轴方向)呈其他任意夹角亦可以实现测量功能，并不局限于本发明提供的实施例。
更具体地，如图6所示，所述读数头可以包括产生干涉信号的镜组和入光/回光信号接收器。所述光学镜组用于产生激光干涉信号，所述入光/回光信号接收器用于提供输入信号及接收输出干涉信号。所述标尺光栅为平面反射/衍射型二维光栅，是光栅干涉仪或光栅编码器的测量基准。读数头通过入光信号接收器接收到由光纤503传输的入光信号，入光信号经过读数头的镜组及标尺光栅500产生包含位移信息的回光信号，并利用光纤503将回光信号输送到电子计数模块504。电子计数模块504用于处理包含位移信息的回光信号。类似的，如图8-9所示，在曝光位光栅安装板120相对投影物镜420的六自由度位移测量系统中，也包括三个探测器，三个探测器间隔设置在曝光位光栅安装板120布置孔其中的三个对角处。如图9所示，探测器的读数头通过读数头安装座固定在曝光位光栅安装板120上，以曝光位光栅安装板120圆形凹槽底平面为安装基准，探测器的标尺光栅通过标尺光栅安装座与投影物镜420固连，标尺光栅平面与圆形凹槽底平面保持垂直并且标尺光栅平面与第一方向即x轴方向呈45度夹角，与探测器读数头相互配合以提供测量基准。本发明中的探测器的标尺光栅和读数头安装位置还可以互换，即探测器的标尺光栅通过标尺安装座固定在曝光位光栅安装板120上，以曝光位光栅安装板120圆形凹槽底平面为安装基准，标尺光栅平面与凹槽底平面保持 垂直并且标尺光栅平面与第一方向即x轴方向呈45度夹角，探测器的读数头通过读数头安装座与对投影物镜420固连，与探测器标尺光栅相互配合以提供测量基准。
所述激光源可以为双频激光器，给测量分系统提供带有稳定频差的两束激光，
这两路激光经过光纤503及光纤分束器502，分别被平均分成6路激光，每两路激光作为参考光和测量光传输至一个探测器的读数头，测量光经过测量路会入射光栅形成衍射光，衍射光与参考光合束产生测量信号。因为光栅与探测器读数头之间有相对位移，会产生光栅多普勒效应，测量信号的频率与相位会发生相应的变化。参考路的光不经过光栅，相位及频率不发生变化。另外激光器还发射一路与频差相等频率的光信号传输至电子计数模块的相位卡部件作为外部参考信号。探测器读数头出来的测量信号经过多模光纤传输至相位卡部件，相位卡部件求解测量信号与参考信号之间的相位差，将得到的相位差信息输入到解算卡进行位移解算，转换为位移测量值。
提取出六组位移信息后组建六自由度解算方程，并进行六自由度位移解算，最终得到光栅安装板相对投影物镜/对准传感器的空间位姿。当光栅安装板相对投影物镜/对准传感器发生任何微小的空间位姿变化，该位移测量系统都能检测到位姿信息变化，进而在光刻机其他分系统中可以作出相应反应进行位置补偿，从而有效抑制或缓解光刻机振动等因素引起投影物镜相对光栅安装板的空间位姿变化的难题。
当然，本发明还可有其它多种实施例，在不背离本发明精神及其实质的情况下，本领域技术人员可根据本发明做出各种相应的改变和变形，但这些相应的改变和变形都属于本发明的权利要求的保护范围。

Claims (10)

  1. 一种光刻机光栅六自由度位移测量系统，其特征在于，包括预处理位测量分系统和曝光位测量分系统，预处理位测量分系统包括预处理位光栅安装板，曝光位测量分系统包括曝光位光栅安装板，并且预处理位光栅安装板、曝光位光栅安装板沿平行于主基板板面的方向间隔布置在主基板下方，所述预处理位光栅安装板、曝光位光栅安装板与光刻机机架固定连接，
    预处理位光栅安装板、曝光位光栅安装板的板体上都设置有布置孔，预处理位测量分系统和曝光位测量分系统都包括至少三个探测器，所述至少三个探测器间隔设置在布置孔内的测量点，通过探测器获得各测量点的二自由度位移组建六自由度解算方程，从而分别解算获得预处理位光栅安装板、曝光位光栅安装板的六自由度位移。
  2. 根据权利要求1所述的光刻机光栅六自由度位移测量系统，其特征在于，所述板体的上表面设置有凹槽，布置孔在所述凹槽内穿透板体，所述布置孔为方形孔，每一探测器都包含读数头和标尺光栅，预处理位测量分系统中，所述读数头和标尺光栅分别安装在预处理位光栅安装板和对准传感器上，且所有标尺光栅平面都沿布置孔对角线方向和边长方向中的一种方向设置；
    曝光位测量分系统中，所述读数头和标尺光栅分别安装在曝光位光栅安装板和投影物镜上，且所有标尺光栅平面都沿布置孔对角线方向和边长方向中的一种方向设置。
  3. 根据权利要求2所述的光刻机光栅六自由度位移测量系统，其特征在于，预处理位测量分系统中，读数头和标尺光栅都是以凹槽底平面为安装基准的形式安装在预处理位光栅安装板上；
    曝光位测量分系统中，读数头和标尺光栅都是以凹槽底平面为安装基准的形式安装在曝光位光栅安装板上。
  4. 根据权利要求1所述的光刻机光栅六自由度位移测量系统，其特征在于，还包括；激光源、光纤分束器和光纤，所述光纤连接于激光源与光纤分束器之间，光纤分束器与探测器之间，以及探测器与电子计数模块之间，并且，激光源到探测器之间采用单模光纤传输，探测器到电子计数模块之间采用多模光纤传输。
  5. 根据权利要求4所述的光刻机光栅六自由度位移测量系统，其特征在于，所述激光源为双频激光器，用于发出具有频差的两束激光，两束激光经过光纤分束器都分解为6路激光，每两路激光通过光纤传输至一个探测器。
  6. 根据权利要求2所述的光刻机光栅六自由度位移测量系统，其特征在于，所述探测器为光栅干涉仪或者光栅编码器，其标尺光栅是平面反射/衍射型二维光栅。
  7. 根据权利要求1所述的光刻机光栅六自由度位移测量系统，其特征在于，预处理位光栅安装板和曝光位光栅安装板是分别通过柔性块与主基板相连。
  8. 根据权利要求1所述的光刻机光栅六自由度位移测量系统，其特征在于，所述测量点为布置孔的三个角点处。
  9. 根据权利要求4所述的光刻机光栅六自由度位移测量系统，其特征在于，激光器还发射一路与频差相等频率的激光信号传输至电子计数模块的相位卡部件作为外部参考信号，每两路激光作为参考光和测量光传输至一个探测器的读数头，测量光经过测量路会入射标尺光栅形成衍射光，衍射光与参 考光合束产生测量信号，测量信号经光纤传输至相位卡部件，相位卡部件求解测量信号与外部参考信号之间的相位差，将得到的相位差信息输入到解算卡进行位移解算，获得位移测量值。
  10. 根据权利要求2所述的光刻机光栅六自由度位移测量系统，其特征在于，
    所述主基板具有与投影物镜、对准传感器对应的通孔，所述投影物镜固定在对应通孔上方，所述对准传感器固定在对应通孔中心。
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