CN107664482A - grating measuring device - Google Patents
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- CN107664482A CN107664482A CN201610616981.1A CN201610616981A CN107664482A CN 107664482 A CN107664482 A CN 107664482A CN 201610616981 A CN201610616981 A CN 201610616981A CN 107664482 A CN107664482 A CN 107664482A
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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
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Abstract
The invention discloses a kind of grating measuring device, including：Light source module, the two light beams different for producing frequency；Grating；Signal processing module and grating measuring probe, enter optical module including double frequency, it is horizontal to detecting module, with reference to detecting module and two symmetrically arranged retroreflector, double frequency enters optical module and is used to receive two light beams and projects it onto grating surface and with reference to detecting module, two light beams project to be interfered to be formed with reference to interference signal with reference to detecting module, in grating surface diffraction occurs for two light beams, diffraction light is projected to corresponding retroreflector respectively, re-diffraction occurs through retroreflector retroeflection to grating surface, the convergence of re-diffraction light projects level and interferes to form level to displacement interferometer signal to detecting module；Signal processing module detection it is horizontal to displacement interferometer signal and it is described refer to interference signal, and calculate the level of grating to displacement.The present invention can be directed to same measurement point, realize horizontal plane X, Y-direction two dimension and meanwhile detect.
Description
Technical field
The present invention relates to IC manufacturing field, more particularly to a kind of grating measuring device.
Background technology
Nano measurement technology is the basis in the fields such as nanoprocessing, nanometer manipulation, nano material.IC industries, precision optical machinery,
MEMS etc. is required for high-resolution, high-precision displacement transducer, to reach nano-precision positioning.With integrated circuit
Developed by leaps and bounds towards extensive, high integration direction, the alignment precision of litho machine requires also more and more higher, correspondingly, obtains
Work stage, the precision of the six-degree of freedom position information of mask platform is taken also to improve therewith.
Interferometer has higher measurement accuracy, up to nanometer scale, in a lithography system, be employed for measuring work stage,
The position of mask platform.However, the measurement accuracy of interferometer nearly reaches the limit at present, while interferometer measurement precision is by ring around
Border has a great influence, and measurement repeatable accuracy is not high, even if environment is fine, error can also exceed 1nm, therefore, the measurement of conventional dry interferometer
System is difficult the requirement for meeting further to improve alignment precision, so the micromicron measurement scheme of high accuracy, high stability compels to be essential
Will.
Optical grating measuring system is affected by environment smaller at work, there is preferable repeatable accuracy, in New Generation Optical etching system
In have started to gradually substitute interferometer, undertake high accuracy, high stability micromicron precision measure task.Publication No. US7389595
United States Patent (USP) propose it is a kind of based on optical fiber transmission two-dimensional grating measuring system, light source and detectable signal light use optical fiber
Transmission.In the patent formula, light source is semiconductor laser, and the position between grating and read head is measured using zero-difference detection mode
Move.But the mode antijamming capability of zero-difference detection is weaker, position data is easily dry by external stray light, electromagnetic field and vibration
The influence disturbed.Application No. CN201210449244 Chinese patent proposes a kind of double frequency heterodyne optical grating measuring system, and this is
System can effectively improve measurement accuracy.But it only has detectable signal to be transmitted by optical fiber, LASER Light Source is placed on one with grating reading head
Rise, volume is big, is not suitable for the usage scenario of spaces compact；In addition, when grating is relative to having Rx, Ry angular deflection between read head
When, measuring system interference performance can reduce, and cause measuring system to fail, and the resetting difficulty of grating and read head is too big in the invention,
Install and use inconvenience.
Publication No. US8300233B2 United States Patent (USP) proposes a kind of optical grating ruler measurement system, and it uses beam orthogonal
Incident grating, prism of corner cube obtain two-dimensional position data horizontally and vertically after returning to diffracted beam.Due to level
To during measurement, the measurement point of X-direction is different with the position of Y-direction measurement point, causes measurement error larger, and needed for grating scale
Light pass surface size is big, and cost is high.
The content of the invention
The present invention provides a kind of grating measuring device, to realize to the horizontal to displacement measurement of grating.
In order to solve the above technical problems, the present invention provides a kind of grating measuring device, including：Light source module, for producing
The different two light beams of frequency；Grating；Signal processing module；And grating measuring probe, including double frequency enter optical module, it is horizontal to
Detecting module, with reference to detecting module and two symmetrically arranged retroreflector, wherein, the double frequency enter optical module be used to receiving it is described
Two light beams, and the two light beams are projected into the grating surface and projected with reference to detecting module, the two light beams
Described to interfere to be formed with reference to interference signal with reference to detecting module, in the grating surface diffraction occurs for the two light beams,
Diffraction light is projected to corresponding retroreflector respectively, and re-diffraction, two beams occur through the retroreflector retroeflection to the grating surface
The convergence of re-diffraction light projects the level and interferes to form level to displacement interferometer signal to detecting module；The signal
Processing module detection it is described it is horizontal to displacement interferometer signal and it is described refer to interference signal, and calculate the level of the grating to position
Move.
Preferably, the grating measuring probe also includes：Vertical measurement module and vertical detecting module, through the double frequency
The light beam entered in the two light beams of optical module outgoing is projected to the grating surface through the vertical measurement module, through described
The diffraction light of grating surface diffraction is projected to the vertical detecting module with another light beams in the two light beams and occurs to do
Relating to form vertical deviation interference signal, the signal processing module receives the vertical deviation interference signal, and with reference to the ginseng
Examine the vertical deviation that interference signal calculates the grating.
Preferably, the optional prism of corner cube of retroreflector.
Preferably, the light source module includes：Laser, isolator, optical splitter, frequency shifter, the first coupler and
Two couplers；The light beam that the laser is sent is two beams by optical splitter light splitting, respectively enters the frequency after isolator
Move device and produce the different two light beams of frequency, the two light beams are sent to after the coupling of first, second coupler respectively
The grating measuring probe.
Preferably, the laser uses gas laser.
Preferably, the frequency shifter is Zeeman frequency divider, birefringence element or two acousto-optic frequency shifters.
Preferably, the grating is one-dimensional grating or two-dimensional grating.
It is preferably, described horizontal to detecting module includes optical splitter, X measures coupler, warp to measurement coupler and Y-direction
Two light beams after the optical grating diffraction are surveyed by the X to measurement coupler and the Y-direction respectively after being divided by the optical splitter
Measure coupler coupling.
Preferably, the optional polarization splitting prism of optical splitter.
Preferably, the light splitting direction of the polarization splitting prism is identical with the pitch direction of the grating.
Preferably, the double frequency, which enters optical module, includes the first beam splitter and the second beam splitter, in the two light beams
It is a branch of be incident to respectively after the first beam splitter beam splitting the grating and it is described refer to detecting module, in the two light beams
Another Shu Jing described in the grating be incident to after the second beam splitter beam splitting respectively and described refer to detecting module.
Preferably, the double frequency, which enters optical module, includes the first beam splitter, the second beam splitter and the 3rd beam splitter, it is described to hang down
Include vertical measurement coupler to detecting module, the light beam in the two light beams is by after the first beam splitter beam splitting points
Be not incident to the vertical measurement module and it is described refer to detecting module, another light beams in the two-beam book are by described
Be incident to respectively after two beam splitter beam splitting the 3rd beam splitter and it is described refer to detecting module, the 3rd beam splitter will receive
Beam splitter after be incident to the vertical measurement module and the grating surface respectively, the vertical measurement coupler will be through institute
The light beam for stating vertical measurement module outgoing closes beam.
Preferably, the vertical detecting module also includes the 4th beam splitter, the 3rd beam splitter is by the light beam of reception
The 4th beam splitter and the grating surface are incident to after beam splitting respectively, is incident to the light beam of the 4th beam splitter and through institute
Coupled after stating the light beam conjunction beam of vertical measurement module outgoing by the vertical measurement coupler.
Include preferably, the double frequency enters optical module：First collimator, the second collimater and angle of wedge piece pair, wherein, institute
State first collimator and the second collimater collimates to the two light beams respectively, appointing in the two light beams after collimation
Anticipate it is a branch of be incident to the angle of wedge piece to carry out angle control.
Preferably, also include being used for the mirror assembly for realizing that light beam turns to.
Preferably, signal transmission is realized by polarization maintaining optical fibre between the light source module and grating measuring probe.
Preferably, the X is transmitted signal by multimode fibre to measurement coupler and Y-direction measurement coupler
To the signal processing module.
Preferably, the vertical measurement module includes：Second polarization splitting prism, the second prism of corner cube and Polarization Control
Device, vertical measuring light beam first transmit through second polarization splitting prism, by Polarization Controller rotatory polarization direction, projection
A diffraction occurs on to grating, the zero order diffracted light of a diffraction enters behind the Polarization Controller rotatory polarization direction again
Second polarization splitting prism is incident upon, is returned to after second polarization splitting prism reflexes to second prism of corner cube
Second polarization splitting prism, is again incident on the grating and re-diffraction occurs afterwards, the zero level in re-diffraction light
Diffraction light projects the vertical detecting module after second polarization splitting prism.
Preferably, the tilt controller uses Faraday rotator or half wave plate.
Preferably, polarization direction and the institute of the light beam of second polarization splitting prism are incident in the two light beams
The placement of the first angle, correspondingly second polarization splitting prism be present in the polarization direction for stating another light beams in two light beams
Direction rotates the first angle, and the polarization direction for the light beam being emitted after the Polarization Controller also rotates the first angle.
Preferably, first angle is 45 degree.
Preferably, the grid direction for being incident on the polarization direction of the light beam of the grating surface and the grating has the
Two angles.
Preferably, second angle is 45+k*90 degree, wherein k is natural number.
Preferably, signal is passed to the signal processing module by the vertical detecting module by multimode fibre.
Preferably, described pass to the signal processing module by multimode fibre with reference to detecting module by signal.
Compared with prior art, the present invention has advantages below：
1st, the achievable all -fiber transmission of the present invention, have strong antijamming capability, measurement accuracy are high, duplicate measurements precision is high,
Without error influences, is simple in construction and install and use the characteristics of convenient, is extremely applicable to the micromicron essence of high-stability requirement
Spend multidimensional measure field.
2nd, the leveling module in grating measuring device of the invention can control two light beams realization level to displacement
Measurement, it is horizontal to detect level to displacement signal and reference optical signal to detecting module, realize that horizontal direction (X/Y) two dimension is visited
Survey, the measurement of X-direction can be made identical with the measurement point of Y-direction, effectively reduce the measurement error come by measured point different band；
The light pass surface size needed for grating is also significantly reduced, reduces grating cost.In addition the present invention can also make grating measuring pop one's head in
Size it is compacter, compress installing space.
3rd, the present invention is directly measured using the zero order light reflected of grating, and vertical measurement distance will not be by spot size
Limitation, it is possible to achieve the vertical measurement of any distance.
4th, the present invention effectively can also merge horizontal direction (X/Y) and vertical (Z) measurement scheme, realize that multiaxis is surveyed
Amount.And use the zero order light reflected that can't be used during horizontal direction (X/Y) measurement to realize during vertical (Z) measurement,
Improve the capacity usage ratio of optical grating ruler measurement system.In the case where not increasing incident beam power, the measurement number of axle is added.
5th, the present invention can produce integrated level very high three axles or multiaxis reading head, suitable for being wanted to space and size
Ask very high, while measurement accuracy and repeatability are required in high sports platform multiaxis Measurement and Control System.
6th, the double frequency heterodyne grating measuring based on all -fiber transmission can be achieved in the present invention.
7th, the present invention is grown using gas laser as light source, coherence length, it is ensured that is popped one's head in grating and grating measuring
Inclination or deflection it is larger when, also can effectively interfere.
8th, the present invention can also realize the separation of LASER Light Source and grating reading head, read head small volume, it is tight be applicable to space
The usage scenario gathered.
9th, the present invention uses double frequency optical detection, and stability is higher, antijamming capability is stronger, and measurement accuracy and repeatability are more
It is excellent.
Brief description of the drawings
Fig. 1 is the structural representation of grating measuring device in the embodiment of the present invention 1；
Fig. 2 is the hot spot distribution schematic diagram on grating in the embodiment of the present invention 1；
Fig. 3 is the structural representation of grating measuring device in the embodiment of the present invention 2；
Fig. 4 is the polarization state change schematic diagram that light beam passes through vertical measurement module in the embodiment of the present invention 2；
Fig. 5 is the structural representation of grating measuring device in the embodiment of the present invention 3.
Shown in figure：
100- grating measurings probe,
110- double frequencies enter optical module, 111- first collimators, the collimaters of 112- second, 113- angle of wedge pieces pair；
The vertical measurement modules of 120-, 121- polarization splitting prisms, 122- prism of corner cubes, 123- Polarization Controllers；
The vertical detecting modules of 130-, the beam splitters of 1301- the 4th, the beam splitters of 1302- the 5th, the remote couplings devices of 1303- the 4th；
140- levels are to measurement module, 141, the prism of corner cubes of 142- first；
150- levels are to detecting module, the beam splitters of 151- first, the beam splitters of 152- second, 153- the first polarization spectro ribs
Mirror, the first remote couplings of 154- device, 155- the second remote couplings devices；The remote couplings devices of 156- the 3rd, 157- speculums, 158-
Three beam splitters；
200- gratings；
300- light source modules, 301- lasers, 302- isolators, 303- beam splitters, 304- speculums, the frequency displacements of 305- first
Device, the frequency shifters of 306- second, the couplers of 307- first, the couplers of 308- second；
701~703- measurement points；
Embodiment
In order to facilitate the understanding of the purposes, features and advantages of the present invention, below in conjunction with the accompanying drawings to the present invention
Embodiment be described in detail.It should be noted that accompanying drawing of the present invention uses using simplified form and non-essence
Accurate ratio, only for the purpose of facilitating and clarifying the purpose of the embodiments of the invention.
Embodiment 1
As shown in figure 1, the grating measuring device of the present embodiment includes：
Light source module 300, the two light beams different for producing frequency；
Grating 200；
Multiple detector (not shown),
Signal processor (not shown)；
And
Grating measuring probe 100, including double frequency enter optical module, level to detecting module, it is right with reference to detecting module and two
Claiming the retroreflector set, in the present embodiment, the retroreflector is preferably prism of corner cube 141,142, wherein, double frequency enters optical module use
In the reception two light beams, and the two light beams are projected into the surface of grating 200 and with reference to detecting module, two-beam
On the surface of grating 200 diffraction occurs for beam, and diffracted ray projects corresponding retroreflector, through the retroreflector retroeflection to grating
Re-diffraction occurs for 200 surfaces, and the convergence of two beam re-diffraction light projects the level and interfered to detecting module, forms water
Detected after putting down to displacement interferometer signal by detector, the two light beams project the detecting module that refers to and interfered, shape
Detected into reference to after interference signal by detector, the signal processor is according to described horizontal to displacement interferometer signal and the ginseng
Examine interference signal and calculate the horizontal to displacement of the grating 200.It is long-range including the 3rd with reference to detecting module described in the present embodiment
Coupler 156, connected between the 3rd remote couplings device 156 and detector by multimode fibre.
Specifically, laser 301, isolator 302, optical splitter, frequency displacement are included with continued reference to Fig. 1, the light source module 300
Device and coupler, optical splitter include beam splitter 303 and speculum 304.
The laser 301 is using any wavelength between 400~1500nm, such as 633nm, 780nm, 980nm.Enter one
Step, wavelength monitor system is additionally provided with the laser 301, for the situation of change to the wavelength of monitoring laser 301, and
Implementation compensation is carried out to wavelength.Further, the laser 301 can directly use gas laser, such as He-Ne Lasers
Device, there is the characteristics of line width is extremely narrow, frequency stabilization performance is good.The laser 301 is used to produce laser beam, the laser beam
For linearly polarized light, polarization direction can be P polarization or S-polarization.
The isolator 302 is arranged on the exit of the laser 301 to stop echo reflection；The isolator 302
It can also be substituted by the optic fibre end with inclined surface, can equally reduce echo reflection influence, be installed on laser 301
Isolator 302 or optic fibre end with inclined surface can improve the stability of laser 301.
The frequency shifter uses acousto-optic frequency shifters, electric light frequency shifter, Zeeman frequency divider or birefringence element, in the present embodiment
Frequency shifter and coupler be two groups, frequency shifter uses acousto-optic frequency shifters, to show that difference is referred to as first, second frequency displacement
Device 305,306 and first, second coupler 307,308.The light beam that laser 301 is sent is divided to for two beams through the beam splitter 303,
A branch of to be projected after first frequency shifter 305 produces certain frequency shift amount through the first coupler 307, another light beam is through speculum
304 enter second frequency shifter 306 and are projected after producing the frequency shift amount different from previous light beam through the second coupler 308.
Further, the two beams frequency is different, has the light beam of certain frequency difference, using polarization maintaining optical fibre remote transmission to grating
Measuring probe 100.
With continued reference to Fig. 1, the double frequency, which enters optical module, to be included：First collimator 111, the second collimater 112 and angle of wedge piece
To 113, wherein, the first collimator 111 and angle of wedge piece are used to collimate a wherein incident beam to 113 and angle control
System, second collimater 112 are used to collimate another incident beam, and the angle of wedge piece is to the 113 control two-beams
The relative depth of parallelism of beam.The double frequency enter optical module also include the first beam splitter 151, the second beam splitter 152, speculum 157 with
And the 3rd beam splitter 158；
For convenience of description, measuring beam will be referred to as to the light beam of 113 outgoing through angle of wedge piece, be emitted through the second collimater 112
Light beam be referred to as reference beam；
Measuring beam is divided to through first beam splitter 151 measures beam splitting for two, wherein a measurement beam splitting projects grating 200
Surface, another measure are transmitted through the 3rd remote couplings device 156 after beam splitting is reflected by speculum 157 through the 3rd beam splitter 158；
Reference beam is divided to through second beam splitter 152 refers to beam splitting for two, wherein one projects grating 200 with reference to beam splitting
Surface, it is another to reflex to the 3rd remote couplings device 156 through the 3rd beam splitter 158 with reference to beam splitting.
With continued reference to Fig. 1, the two light beams after optical module adjustment are entered by double frequency, is respectively perpendicular and projects on grating 200,
Projected respectively on corresponding prism of corner cube 141,142 after diffraction occurs on grating 200, after the reflection of prism of corner cube 141,142
Project again on grating 200, again after the diffraction of grating 200, the convergence of two light beams projects described horizontal to detecting module.
The level includes to detecting module：First polarization splitting prism 153, the first remote couplings device 154 and second are remote
Journey coupler 155, it is remote that the two light beams after re-diffraction respectively enter first after the beam splitting of the first polarization splitting prism 153
The remote couplings device 155 of journey coupler 154 and second is coupled, and coupled signal is transferred into detector by multimode fibre afterwards.
As shown in Fig. 2 hot spot caused by grating measuring probe 100, distribution arrangement above grating 200 relative to
The pitch direction cant angle theta angle of grating 200, wherein θ can be any angle of 0 to 360 degree and 0 to 360 degree multiple.Such as Fig. 2
It is shown, measure the 2-d position measurement of horizontal direction, you can so that X, Y-direction displacement are integrated together into detection so that grating is surveyed
Amount probe 100 it is compact-sized, and X to the measurement point 701~703 with Y-direction in same point, can avoid because of X, Y-direction
Measurement point differs the error brought, and can also make hot spot distribution on grating 200 compact, the reduction detection area of grating 200, improve light
The surface utilisation of grid 200, reduces cost.
Incident beam on grating 200 can be same polarization direction, and first, second remote couplings device 154,155 can be straight
Detection is connect, is not required to increase polarizer, the power attenuation of whole system can be reduced, improve the efficiency of light energy utilization.
The present invention uses double frequency optical detection, and stability is higher, antijamming capability is stronger, and measurement accuracy and repeatability are more excellent.
Preferably, first, second, third beam splitter 151,152,158 can be substituted using grating, light beam is realized
Separation.
Reference picture 1, the following detailed description of in embodiment grating measuring device it is horizontal to measurement implementation process：
It is f that He-Ne laser in light source module 300, which sends frequency,0Helium neon laser beam, after isolator 302, by
Optical splitter is divided into two-way, respectively incident first frequency shifter 305 and the second frequency shifter 306, wherein, the frequency displacement of the first frequency shifter 305
Measure as Δ f1, by the helium neon laser beam of the first frequency shifter 305, frequency is changed into f0+Δf1；The frequency shift amount of second frequency shifter 306 is
Δf2, by the helium neon laser beam of the second frequency shifter 306, frequency is changed into f0+Δf2；This two light beams is respectively with the first coupler
307 and second coupler 308 be coupled to polarization maintaining optical fibre, remote transmission to grating measuring probe 100.
As depicted in figs. 1 and 2, frequency f0+Δf1And f0+Δf2Two beam laser beams, respectively by first collimator 111
Collimated with the second collimater 112, and make two laser parallel the relative depth of parallelism of 113 control two lasers with angle of wedge piece.For side
Just describe, be f by frequency0+Δf1Laser beam be referred to as measuring beam, be f by frequency0+Δf2Laser beam be referred to as reference light
Beam.
The measuring beam by the first beam splitter 151 be divided to for two measurement beam splitting, one measurement beam splitting polarization direction relative to
The pitch direction cant angle theta angle of grating 200, and vertical incidence grating 200, hot spot 701 as shown in Figure 2, take -1 order diffraction light simultaneously
With in the retroeflection of prism of corner cube 141 to grating 200, hot spot 703 as shown in Figure 2, the first polarization is emitted to after diffraction occurs again
Amici prism 153, the light splitting direction of first polarization splitting prism 153 are identical with the pitch direction of grating 200.Another measurement
Beam splitting is projected in the 3rd remote couplings device 156, and detector is remotely projected by the 3rd remote couplings device 156, as with reference to letter
Number.
The reference beam is divided to by the second beam splitter 152 refers to beam splitting for two, wherein one is relative with reference to beam splitting polarization direction
In the pitch direction cant angle theta angle of grating 200, and vertical incidence grating 200, hot spot 702 as shown in Figure 2, take+1 order diffraction light
And with the retroeflection of prism of corner cube 142 to grating 200, hot spot 703 as shown in Figure 2, it is inclined to be emitted to first after generation diffraction again
Shake Amici prism 153.It is another to be projected with reference to beam splitting in the 3rd remote couplings device 156, remotely thrown by the 3rd remote couplings device 156
Detector is mapped to, as reference signal.
For above-mentioned ± 1 order diffraction light after the first polarization splitting prism 153, a part of transmission-polarizing light is long-range by second
Coupler 155 couples, remote transmission to detector, detects double-frequency interference signal；Another part polarization by reflection light is remote by first
Journey coupler 154 couples, remote transmission to detector, detects double-frequency interference signal.
When grating 200 is along X to when moving Δ X, detects the interference containing tested displacement through the first remote couplings device 154 and believe
Number, its fringe number is N1：
N1=[(f0+Δf2)T1+2ΔX/d]-[(f0+Δf1)T1- 2 Δ X/d]=(Δ f2-Δf1)T1+4ΔX/d (1)
Wherein, T1For the time used in motion Δ X displacements, d is the pitch of grating 200.Frequency is f0+Δf1Light beam exist
Diffraction, the Δ of phase place change -2 X/d occur twice for -1 order diffraction light direction of grating 200；Frequency is f0+Δf2Light beam in grating
Diffraction, the Δ of phase place change+2 X/d occur twice for 200+1 order diffraction light direction.
The reference signal without tested displacement is detected from the 3rd remote couplings device 156, its fringe number is N2：
N2=(f0+Δf2)T1-(f0+Δf1)T1=(Δ f2-Δf1)T1 (2)
The fringe number that two detectors detect is subtracted each other, can obtain grating 200 relative to grating measuring probe 100 in X
To the displacement X of motion：
Δ X=d (N1-N2)/4 (3)
When grating 200 moves Δ Y along Y-direction, the interference containing tested displacement that is detected from the second remote couplings device 156
Signal, its fringe number are N3：
N3=[(f0+Δf2)T2+2ΔY/d]-[(f0+Δf1)T2- 2 Δ Y/d]=(Δ f2-Δf1)T2+4ΔY/d (4)
Wherein, T2For the time used in motion Δ Y displacements, d is the pitch of grating 200.Frequency is f0+Δf1Light beam exist
Diffraction, the Δ of phase place change -2 Y/d occur twice for -1 order diffraction light direction of grating 200；Frequency is f0+Δf2Light beam in grating
Diffraction, the Δ of phase place change+2 Y/d occur twice for 200+1 order diffraction light direction.
Its fringe number detected with reference signal detector is subtracted each other, you can obtain grating 200 relative to grating measuring
Displacement Y of the probe 100 in Y-direction motion：
Δ Y=d (N3-N2)/4 (5)
It should be noted that in grating measuring probe 100 hot spot distribution arrangement relative to grating 200 pitch direction
Cant angle theta angle, θ can be any angle of 0 to 360 degree and 0 to 360 degree multiple, for realizing that X and/or Y-direction position are surveyed
Amount.When the angle is 0,90,180,360 degree and 90 degree of multiple, X or Y position are may detect, realizes the water of grating 200
Square to one-dimensional position measure.When the angle for angle 0 more than, in addition to 90,180,360 degree and 90 degree of multiple when,
X and/or Y position are may detect, realizes grating scale horizontal direction 2-d position measurement.Particularly, when the angle be 45 degree,
135 degree and during 45+k*90 degree (k is natural number), groove of the grating measuring probe 100 in X and Y-direction relative to grating 200
Direction is symmetrical, and the light signal energy of X and Y-direction is evenly distributed, and can preferably realize the 2-d position measurement of horizontal direction.
Embodiment 2
The present embodiment and the difference of embodiment 1 are：The present embodiment can be realized vertical and horizontal to displacement measurement simultaneously.
As shown in figure 3, the present embodiment adds relative to embodiment 1：Double frequency is arranged on to enter between optical module and grating 200
Light path on vertical measurement module, and the vertical detecting module being correspondingly arranged with the vertical measurement module.
With continued reference to Fig. 3, the vertical measurement module includes：Second polarization splitting prism 121, the second prism of corner cube 122
With Polarization Controller 123, the measuring beam that double frequency enters optical module outgoing first transmits through the second polarization splitting prism 121, by polarizing
The rotatory polarization direction of controller 123, projects and diffraction occurs on grating 200, and -1 order diffraction light in diffraction light is incident to pyramid
Prism 141, the zero order diffracted light in diffraction light is reflected back Polarization Controller 123, again through the rotatory polarization side of Polarization Controller 123
To light beam is returning to second by being reflected during the second polarization splitting prism 121, and by the second prism of corner cube 122
Polarization splitting prism 121, it is again incident on grating 200 and returns to zero order diffracted light, be finally projected to vertical detecting module.
The vertical detecting module includes the 4th remote couplings device 1303 and the 4th beam splitter 1301, and the double frequency enters optical mode
Block also includes：5th beam splitter 1302.
The present embodiment is realized vertical and horizontal as follows to displacement measurement detailed process：Measuring beam is by the first beam splitter 151
It is divided into two beams, the surface of grating 200 that a measurement beam splitting projects through the vertical measurement module, spreads out on the surface of grating 200
Penetrate, -1 order diffraction light projection in diffraction light to prism of corner cube 141 is used for level to measurement, and zero order diffracted light is through vertical measurement mould
Block is reflexed to after re-diffraction occurs for grating 200 and reflexes to the 4th beam splitter 1301 again, and institute is transmitted to through the 4th beam splitter 1301
State the 4th remote couplings device 1303 and be used for vertical measurement；Another measurement beam splitting is successively through the speculum 157, the 3rd beam splitter
Projected after 158 the 3rd remote couplings device 156 be used for formed refer to interference signal；
Reference beam is first divided to by the second beam splitter 152 refers to beam splitting for two, wherein a reference beam splitting is by the 5th beam splitting
Mirror 1302 is again split into two beams, and a part, which is projected directly on grating 200, is used for level to measurement, and another part is through the 4th beam splitting
Mirror 1301 projects the 4th remote couplings device 1303 and is used for vertical measurement.Another reference beam splitting is through the 3rd beam splitter
158 project the 3rd remote couplings device 156 be used for formed refer to interference signal.
Specifically, the light source module 300 sends the f that frequency is respectively0+Δf1、f0+Δf2Two-beam, to show area
Not, it is f by frequency0+Δf1Light beam be referred to as measuring beam, be f by frequency0+Δf2Light beam be referred to as reference beam.Its
In, measuring beam is as shown in Figure 4 by polarization state situation of change during vertical measurement module.The polarization direction of measuring beam is relative
There is angle α in the polarization direction of reference beam.The placement direction of second polarization splitting prism 121 also corresponding rotation alpha angle.Measure light
After beam the second polarization splitting prism 121 of incidence, polarization direction is constant, after Polarization Controller 123, polarization direction rotation alpha angle, this
When measuring beam polarization direction it is identical with the polarization direction of reference beam, be in θ angles all with the grid direction of grating 200, when
The right measuring beam and reference beam impinge perpendicularly on the surface of grating 200.In the present embodiment, angle α is 45 degree.
Further, the light splitting direction of first polarization splitting prism 153 is identical with the pitch direction of grating 200.
When grating 200 relative to grating measuring probe 100 when Z-direction is vertical mobile, projected from vertical measurement module
F is included in the 0 order diffraction light gone out0+Δf1+ Δ Z displacement information, after it closes beam with one with reference to beam splitting, the 4th remote couplings device
1303 pairs its couple, formed (Δ f2-Δf1- Δ Z) interference signal, and detector is sent to by multimode fibre.Signal transacting
Module calculates (Δ f2-Δf1- Δ Z) interference signal with detecting the reference without tested displacement from the 3rd remote couplings device 156
The difference of interference signal it is known that grating 200 relative to grating measuring probe 100 in Z-direction displacement, it is vertical so as to realize
To measurement.
Embodiment 3
The present embodiment and the difference of embodiment 2 are：Vertical detecting module in the present embodiment does not include the 4th beam splitter
1301, by the measuring beam with vertical deviation information that grating returns using other manner and through the beam splitting of the 5th beam splitter 1302
Reference beam afterwards is synthetically formed interference signal a1, realizes vertical measurement.(it is used for as shown in Figure 5 not shown in figure horizontal to survey
The part of amount), reference beam reflects by the 5th beam splitter 1302, into the second polarization splitting prism 121, and with vertical position
Output is coupled by the 4th remote couplings device 1303 after the measuring beam conjunction beam of confidence number.
The scheme for being used to synthesize light beam shown in the present apparatus, specific implementation can use various ways, can be embodiment 2
In by the 4th beam splitter 1301 realize closing light measurement or by the 5th beam splitter 1302 and the second polarization splitting prism
121 combinations realize that closing light measures.Light combination method is not limited to described above, can also use other optical elements, such as half
Wave plate, quarter-wave plate and other servicing units are realized.The structure of grating measuring probe 100 can according to demand not
Together, increase a number of polarization splitting prism and/or speculum, foldover design is carried out to light path, to adapt to different spaces
Size requirements.
Obviously, those skilled in the art can carry out the spirit of various changes and modification without departing from the present invention to invention
And scope.So, if these modifications and variations of the present invention belong to the claims in the present invention and its equivalent technologies scope it
Interior, then the present invention is also intended to including these changes and modification.
Claims (25)
- A kind of 1. grating measuring device, it is characterised in that including：Light source module, the two light beams different for producing frequency；Grating；Signal processing module；And grating measuring probe, including double frequency enters optical module, level is symmetrically set to detecting module, with reference to detecting module and two The retroreflector put, wherein, the double frequency enters optical module and is used to receive the two light beams, and the two light beams are projected into institute State grating surface and with reference to detecting module, the two light beams project the detecting module that refers to and interfere to be formed with reference to dry Signal is related to, in the grating surface diffraction occurs for the two light beams, and diffraction light is projected to corresponding retroreflector respectively, through described To the grating surface re-diffraction occurs for retroreflector retroeflection, and the convergence of two beam re-diffraction light projects described horizontal to detection mould Block interferes to form level to displacement interferometer signal；Signal processing module detection it is described it is horizontal to displacement interferometer signal and it is described refer to interference signal, and calculate the light Grid it is horizontal to displacement.
- 2. grating measuring device as claimed in claim 1, it is characterised in that the grating measuring probe also includes：Vertical survey Module and vertical detecting module are measured, the light beam in the two light beams of optical module outgoing is entered through the double frequency through the vertical survey Module projects are measured to the grating surface, the diffraction light through the grating surface diffraction and the another light beam in the two light beams Beam is projected to the vertical detecting module and interferes to form vertical deviation interference signal, described in the signal processing module reception Vertical deviation interference signal, and with reference to the vertical deviation that the grating is calculated with reference to interference signal.
- 3. grating measuring device as claimed in claim 1, it is characterised in that the optional prism of corner cube of retroreflector.
- 4. grating measuring device as claimed in claim 1, it is characterised in that the light source module includes：Laser, isolation Device, optical splitter, frequency shifter, the first coupler and the second coupler；The light beam that the laser is sent is after isolator, by described Optical splitter light splitting is two beams, respectively enters the frequency shifter and produces the different two light beams of frequency, the two light beams point The grating measuring probe is not sent to after the coupling of first, second coupler.
- 5. grating measuring device as claimed in claim 4, it is characterised in that the laser uses gas laser.
- 6. grating measuring device as claimed in claim 4, it is characterised in that the frequency shifter is Zeeman frequency divider, birefringence Element or two acousto-optic frequency shifters.
- 7. grating measuring device as claimed in claim 1, it is characterised in that the grating is one-dimensional grating or two-dimentional light Grid.
- 8. grating measuring device as claimed in claim 1, it is characterised in that the level includes optical splitter, X to detecting module Distinguish to measurement coupler and Y-direction measurement coupler, the two light beams after the optical grating diffraction after being divided by the optical splitter Coupled by the X to measurement coupler and Y-direction measurement coupler.
- 9. grating measuring device as claimed in claim 8, it is characterised in that the optional polarization splitting prism of optical splitter.
- 10. grating measuring device as claimed in claim 9, it is characterised in that the light splitting direction of the polarization splitting prism with The pitch direction of the grating is identical.
- 11. grating measuring device as claimed in claim 1, it is characterised in that the double frequency, which enters optical module, includes the first beam splitting Mirror and the second beam splitter, a branch of in the two light beams be incident to respectively after the first beam splitter beam splitting the grating and It is described to refer to detecting module, the light is incident to respectively after the second beam splitter beam splitting described in another Shu Jing in the two light beams Grid and described refer to detecting module.
- 12. grating measuring device as claimed in claim 2, it is characterised in that the double frequency, which enters optical module, includes the first beam splitting Mirror, the second beam splitter and the 3rd beam splitter, the vertical detecting module include vertical measurement coupler, in the two light beams Light beam by being incident to the vertical measurement module and described referring to detecting module, institute respectively after the first beam splitter beam splitting Another light beams in two-beam book are stated by being incident to the 3rd beam splitter and described after the second beam splitter beam splitting respectively With reference to detecting module, the 3rd beam splitter will be incident to the vertical measurement module and described respectively after the beam splitter of reception Light beam through the vertical measurement module outgoing is closed beam by grating surface, the vertical measurement coupler.
- 13. grating measuring device as claimed in claim 12, it is characterised in that the vertical detecting module also includes the 4th point Shu Jing, the 3rd beam splitter will be incident to the 4th beam splitter and the grating surface respectively after the beam splitter of reception, It is incident to the light beam of the 4th beam splitter and after the light beam of the vertical measurement module outgoing closes beam by the vertical measurement Coupler couples.
- 14. the grating measuring device as described in claim 1,11,12 or 13, it is characterised in that the double frequency enters optical module bag Include：First collimator, the second collimater and angle of wedge piece pair, wherein, the first collimator and the second collimater are respectively to described Two light beams are collimated, in the two light beams after collimation it is any it is a branch of be incident to the angle of wedge piece to carry out angle control System.
- 15. the grating measuring device as described in claim 11,12 or 13, it is characterised in that also include being used to realize that light beam turns To mirror assembly.
- 16. grating measuring device as claimed in claim 1, it is characterised in that the light source module is visited with the grating measuring Signal transmission is realized by polarization maintaining optical fibre between head.
- 17. grating measuring device as claimed in claim 8, it is characterised in that the X surveys to measurement coupler and the Y-direction Signal is passed to the signal processing module by amount coupler by multimode fibre.
- 18. grating measuring device as claimed in claim 2, it is characterised in that the vertical measurement module includes：Second polarization Amici prism, the second prism of corner cube and Polarization Controller, vertical measuring light beam are first saturating through second polarization splitting prism Penetrate, by Polarization Controller rotatory polarization direction, project and a diffraction occurs on grating, the zero order diffracted light of a diffraction is again Second polarization splitting prism is incident to behind the Polarization Controller rotatory polarization direction, through the second polarization spectro rib Mirror returns to second polarization splitting prism after reflexing to second prism of corner cube, is again incident on afterwards on the grating Generation re-diffraction, the zero order diffracted light in re-diffraction light project the vertical spy after second polarization splitting prism Survey module.
- 19. grating measuring device as claimed in claim 18, it is characterised in that the tilt controller uses Faraday rotation Device or half wave plate.
- 20. grating measuring device as claimed in claim 18, it is characterised in that described second is incident in the two light beams The first angle be present in the polarization direction of the light beam of polarization splitting prism and the polarization direction of another light beams in the two light beams, Correspondingly the placement direction of second polarization splitting prism rotates the first angle, the light beam being emitted after the Polarization Controller Polarization direction also rotate the first angle.
- 21. grating measuring device as claimed in claim 20, it is characterised in that first angle is 45 degree.
- 22. grating measuring device as claimed in claim 1, it is characterised in that be incident on the inclined of the light beam of the grating surface The second angle be present in the shake grid direction of direction and the grating.
- 23. grating measuring device as claimed in claim 22, it is characterised in that second angle is 45+k*90 degree, wherein K is natural number.
- 24. grating measuring device as claimed in claim 2, it is characterised in that the vertical detecting module passes through multimode fibre Signal is passed into the signal processing module.
- 25. grating measuring device as claimed in claim 1, it is characterised in that described to pass through multimode fibre with reference to detecting module Signal is passed into the signal processing module.
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Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102906545A (en) * | 2010-03-30 | 2013-01-30 | 齐戈股份有限公司 | Interferometric encoder systems |
| CN102944176A (en) * | 2012-11-09 | 2013-02-27 | 清华大学 | Displacement measuring system of heterodyne grating interferometer |
| US20130250307A1 (en) * | 2011-10-26 | 2013-09-26 | Mori Seiki Co., Ltd. | Displacement Detecting Device |
| CN103604376A (en) * | 2013-11-19 | 2014-02-26 | 哈尔滨工业大学 | Double frequency laser grating interference three-dimensional measurement method and system with optical aliasing resistance |
| CN104949616A (en) * | 2014-03-25 | 2015-09-30 | 上海微电子装备有限公司 | Retro-reflection grating scale measurement system and application thereof |
-
2016
- 2016-07-29 CN CN201610616981.1A patent/CN107664482B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102906545A (en) * | 2010-03-30 | 2013-01-30 | 齐戈股份有限公司 | Interferometric encoder systems |
| US20130250307A1 (en) * | 2011-10-26 | 2013-09-26 | Mori Seiki Co., Ltd. | Displacement Detecting Device |
| CN102944176A (en) * | 2012-11-09 | 2013-02-27 | 清华大学 | Displacement measuring system of heterodyne grating interferometer |
| CN103604376A (en) * | 2013-11-19 | 2014-02-26 | 哈尔滨工业大学 | Double frequency laser grating interference three-dimensional measurement method and system with optical aliasing resistance |
| CN104949616A (en) * | 2014-03-25 | 2015-09-30 | 上海微电子装备有限公司 | Retro-reflection grating scale measurement system and application thereof |
Non-Patent Citations (2)
| Title |
|---|
| 张志平: "加速度对激光双频干涉仪测量误差的影响", 《中国激光》 * |
| 池峰: "双频激光干涉测量中的环境补偿技术", 《中国激光》 * |
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| WO2020216325A1 (en) * | 2019-04-26 | 2020-10-29 | 上海微电子装备（集团）股份有限公司 | Displacement measuring apparatus, displacement measuring method and photolithography device |
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