CN101216290A - High precision six-axis laser measurement device and measurement method - Google Patents

Abstract

The invention relates to a high-precision six-axis laser measurement device and a method thereof. The device comprises a laser interferometer system, a workbench and a motor execution system. The laser interferometer system comprises three laser interferometers vertically arranged along x-axis and used for measuring the displacement of the workbench along three vertical three axes (Z, Theta x, Theta y), two laser interferometers arranged along x-axis and used for measuring the displacement X of the workbench along x-axis and a rotor rotation angle Theta z, a laser interferometer arranged along y-axis and used for measuring the displacement Y of the workbench along y-axis. The workbench is connected with the motor execution system via a washer and driven by the motor execution system to perform spatial six-axis displacement. The invention has the advantages of high measurement precision, low error, and strong generality; and is suitable for calibration of non-contact type and contact type displacement sensors, and calibration of the displacement accuracy of the multi-axis motor executor.

Description

High precision six-axis laser measurement device and measuring method

Technical field

The invention belongs to the high-acruracy survey field, especially about a kind of high precision six-axis laser interferometric measuring means and measuring method thereof.

Background technology

Laser interferometry has been widely used in the high precision position measurement at present, and it has the precision height, good reliability, and error is disturbed little characteristics.Especially being applied to etching system and silicon chip in IC industry aims at.Ripe laser measuring device for measuring generally uses one-parameter to measure, but a lot of high-acruracy survey occasions is arranged, and needs definite parameter a lot, can't satisfy application demand, so need use the multiaxis measuring system.

Six measuring systems can be measured three line position amounts of exercise and three amounts of spin of testee in real time, and its measuring method and technical research are the technical barriers that people attempt to solve always.Existing high-accuracy multiple-degree-of-freedom measurement mechanism is to realize by the transformation to laser optical path, its light path arrangement more complicated, processing and manufacturing precision and installation accuracy to optical device have all proposed very high requirement, and measuring accuracy is subjected to the interference of environmental factor bigger.Simultaneously, because laser interferometry requires it to measure mask higher reflectivity and smooth finish are arranged, the versatility of its measurement mechanism has been subjected to very big restriction.

Summary of the invention

The present invention provides a kind of high precision six-axis laser measurement device and measuring method thereof for overcoming the above problems, and device comprises laser interferometry system, worktable, motion executive system;

Laser interferometry system comprises six single shaft laser interferometer: vertical three laser interferometer of arranging along the z axle are responsible for measuring vertical three (Z, θ x, θ y) amount of exercise, level is responsible for measurement of x to amount of exercise X and rotational angle theta z to two laser interferometer of arranging along the x axle, is responsible for measuring y to amount of exercise Y along the laser interferometer that the y axle is arranged.

Worktable is provided with compression ring, leans on fixedly measured object of absorption affinity, connects the motion executive system by pad; The motion executive system comprises vertical three-axis moving actuator and level to the motion platform, can drive worktable and do six motions in space.

Be provided with a mounting bracket, when surveying instrument is calibrated, can be installed on this support, drive working table movement by the motion executive system with being calibrated instrument, and with the working table movement amount as measuring basis, can reduce because of the material long term thermal caused systematic error of drifting about.

High precision six-axis laser measuring method of the present invention, its method step is as follows:

(1) determines a reference field for laser interferometer, set up space coordinates, and make true origin O be positioned at the center of three vertical laser interferometer measurement point A, B, C;

(2), determine the x of 3 of A, B, C, the y coordinate according to the position of three vertical laser interferometer relative coordinate systems; Determine 3 z coordinate according to the height value h of three measurement points that vertical laser interferometer is surveyed;

(3) fit out the plane equation ax+by+cz=1 on its plane, place according to the coordinate figure of 3 of A, B, C;

(4) calculate vertical three Z, the amount of exercise of θ x, θ y according to the geometric relationship of known plane and space coordinates.

(5) in the surface level x to 2 of two the laser interferometer measurement D, the E that arrange along the axial amount of exercise of x, according to geometric relationship between measurement result and DE, the evaluation work platform along z Shaft angle θ z, and considers that θ z is to influence that X produced along x direction of principal axis amount of exercise X and worktable.

(6) y and considers that rotational angle theta z is to influence that Y produced to the amount of exercise Y of the laser interferometer measurement worktable of arranging along the y axle in the surface level.

High precision six-axis laser measurement device of the present invention has following characteristics:

Apparatus structure is flexible, is combined by measuring system and motion executive system, is convenient to dismounting, and vertical measurement and level are separate to measuring.The measuring accuracy height, error is little, and highly versatile is applicable to contactless and calibration tangent displacement sensor, can be used for simultaneously the kinematic accuracy of multiaxial motion actuator is demarcated.

Description of drawings

Fig. 1 is the installation drawing of high precision six-axis measurement mechanism of the present invention;

Fig. 2 is the layout of laser interferometer of the present invention;

Fig. 3 is the coordinate system figure that measuring method of the present invention is set up;

Synoptic diagram was calculated at interferometer measurement face inclination angle when Fig. 4 was vertical measurement;

The perspective view of interferometer measurement face normal vector on xoy face when Fig. 5 is vertical measurement;

Fig. 6 is that X, Y and θ z measure the calculating synoptic diagram;

Fig. 7 is the worktable synoptic diagram of band compression ring.

Embodiment

Introduce measurement mechanism of the present invention and measuring method in detail below in conjunction with Figure of description:

A specific embodiment of the present invention, apparatus structure as shown in Figure 1, comprising laser interferometry system (1), worktable (2) and motion executive system, the motion executive system is made up of catenary motion actuator (4) and tangential movement actuator (5).Laser interferometry system is made up of to three single shaft laser interferometer of arranging three the single shaft laser interferometer and the level of vertical layout.Worktable (2) be a kind of surface smoothness and smooth finish all than higher optical device, form by little smart glass processing, upper surface and adjacent side can be used as the measurement face of laser interferometer, as shown in Figure 7 through polishing, plated film.Worktable upper surface has the compression ring (201) of different-diameter, each corresponding pore (203) of each compression ring, and pore links to each other with vacuum pipe by operation valve.When the surveying instrument that is calibrated has particular requirement to measurement face, upward select the compression ring of suitable dimension to adsorb at worktable (2) to measuring thing according to measuring the object plane shape.Six vertebra shape fixed orifices (202) are arranged on the worktable (2), fix by the absorption affinity and the motion executive system of six vertebra shape magnet.In order to alleviate own wt, worktable (2) adopts hollow structure.Accompany one deck pad (3) between the catenary motion controller (4) of worktable (2) and motion executive system, pad (3) adopts the bigger metal material processing of deformation coefficient to form, can absorb motion actuators owing to be heated for a long time or stressed caused microdeformation, in order to avoid damage worktable (2).Have the fixed orifice of multiple model on the pad (3), so that connect the catenary motion actuator (4) of worktable (2) and motion executive system.

Measuring system is made up of six high-precision laser interferometers, and its layout as shown in Figure 2.Vertical three (Z and θ x, θ y) amount of exercise is responsible for measuring in the laser interferometer of vertical layout (101), (102) and (103), and level is used for measured X and θ z to laser interferometer (104), (105) arranged, and y is finished by interferometer (106) to measuring.

Vertical three (Z and θ x, θ y) amount of exercise is according to three laser interferometer (101) of vertically arranging, measurement result h1, h2, the h3 of (102) and (103), reaches that relative position relation calculates between three interferometers.At first determine a reference field for laser interferometer, set up coordinate system as shown in Figure 3 then, make true origin O be positioned at the center of three interferometer measurement points, x axle and y axle are on reference field.When vertical interferometer measurement face and reference field coincidence, with interferometer (101), (102) and (103) zero clearing.If should measurement face place plane equation be ax+by+cz=1, the coordinate of three measurement points of interferometer be A (x ₁, y ₁, z ₁), B (x ₂, y ₂, z ₂) and C (x ₃, y ₃, z ₃), wherein, x that A, B, C are ordered and y coordinate can calculate with respect to the position of coordinate system relation according to three interferometers, and the z measured height value h that is interferometer.Coordinate figure according to 3 of A, B, C can calculate a, b, c, and then determines interferometer measurement face place plane equation.If the interferometer measurement face is θ with respect to the reference field angle, as shown in Figure 4,

Be the normal vector of measurement face by true origin O, then { { 0,0, the angle of 1} is θ to this normal vector for c} and z axle for a, b.Perpendicular to being decomposed into θ x and θ y on x axle and the y direction of principal axis, then θ x and θ y are the corner of wafer-supporting platform upper surface with respect to zero plane with edge, θ angle.If the P point is projected as P on the xoy face ₀,

With x axle clamp angle be φ, as Fig. 5.

Because θ x and θ y are very little, so have following approximation relation:

The θ angle is a vector $\stackrel{\&RightArrow;}{\mathrm{OP}}=\{a,b,c,\}$ With the z axle 0,0, the angle of 1}, $\cos \mathrm{\&theta;}=\frac{c}{\sqrt{a^2+{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="S2007101737227E00011.png"\; state="\{\{state\}\}">b</figure-callout>}}^2+{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="S2007101737227E00011.png"\; state="\{\{state\}\}">c</figure-callout>}}^2}}$

The φ angle is a vector $\stackrel{\&RightArrow;}{{\mathrm{OP}}_0}=\{a,b,0\}$ With the x axle 1,0,0) and angle,

So:

Make x=0, y=0, get final product 0 height value $Z=\frac{1}{c}.$ That is:

$\left\{\begin{array}{c}Z=\frac{1}{c}\\ \mathrm{\&theta;x}=\frac{b}{\sqrt{a^2+b^2+c^2}}\\ \mathrm{\&theta;y}=-\frac{a}{\sqrt{a^2+b^2+{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="S2007101737227E00011.png"\; state="\{\{state\}\}">c</figure-callout>}}^2}}\end{array}\right.$

Worktable is recorded by two laser interferometer that are arranged in parallel along directions X (104), (105) to the x displacement to corner and level along z, supposes that (104) and (105) measurement result is respectively h4 and h5, then $\mathrm{\&theta;z}\&ap;\frac{h5-h4}{\left|\stackrel{\&OverBar;}{\mathrm{DE}}\right|}.$ Worktable along Z to corner influence x to measurement result, as shown in Figure 6 because θ z makes x to having produced increment If

Distance is d, then

Distance is

Promptly

Distance is

X to amount of exercise is $X=\frac{1}{2}(h4+h5)-d(\frac{1}{\cos \mathrm{\&theta;z}}-1).$ Level is responsible for measuring y to amount of exercise to the interferometer of arranging (106), as shown in Figure 6, supposes that (106) measurement result is h6, and in like manner, θ z influences y to measurement result, and promptly y to amount of exercise is $Y=h6-d(\frac{1}{\cos \mathrm{\&theta;z}}-1).$ Then:

$\left\{\begin{array}{cc}& X=\frac{1}{2}(h4+h5)-d(\frac{1}{\cos \mathrm{\&theta;z}}-1)\\ & Y=h6-d(\frac{1}{\cos \mathrm{\&theta;z}}-1)\\ & \mathrm{\&theta;z}=\frac{h5-h4}{\left|\stackrel{\&OverBar;}{\mathrm{DE}}\right|}\end{array}\right.$

That more than introduces only is based on a preferred embodiment of the present invention, can not limit scope of the present invention with this.Any mechanism of the present invention is done replacement, the combination, discrete of parts well know in the art, and the invention process step is done well know in the art being equal to change or replace and all do not exceed exposure of the present invention and protection domain.

Claims (6)

1. a high precision six-axis laser measurement device is used for surveying instrument is carried out calibrate, it is characterized in that comprising: laser interferometry system, worktable and motion executive system;

Described laser interferometry system comprises six single shaft laser interferometer: vertical three laser interferometer of arranging along the z axle, be responsible for measuring vertical three (Z, θ x, θ y) amount of exercise, three horizontally disposed laser interferometer be responsible for the horizontal x of measurement to amount of exercise X, y to amount of exercise Y and gyration θ z;

Described worktable connects the motion executive system by pad, and is driven by the motion executive system, can do six motions in space, and tested material is adsorbed on the worktable, and moves with worktable.

2. high precision six-axis laser measurement device as claimed in claim 1, it is characterized in that described laser interferometry system, determine that a reference field sets up space coordinates, vertically three single shaft laser interferometer are set along the z axle, level is provided with a single shaft laser interferometer to two single shaft laser interferometer are set along the x axle along the y axle.

3. high precision six-axis laser measurement device as claimed in claim 1 is characterized in that described motion executive system comprises that vertical three-axis moving actuator and level are to the motion platform.

4. high precision six-axis laser measurement device as claimed in claim 1 is characterized in that also being provided with on the described worktable compression ring, leans on fixedly tested material of vacuum suction.

5. high precision six-axis laser measurement device as claimed in claim 1 is characterized in that also being provided with on the mounting bracket, is used for fixing the surveying instrument that is calibrated.

6. high precision six-axis laser measuring method, it is as follows to be used for that surveying instrument is carried out its method step of calibrate:

(1) determines a reference field for laser interferometer, set up space coordinates, and make true origin O be positioned at the center of three vertical laser interferometer measurement point A, B, C;

(2), determine the x of 3 of A, B, C, the y coordinate according to the position of three vertical laser interferometer relative coordinate systems; Determine 3 z coordinate according to the height value h of three measurement points that vertical laser interferometer is surveyed;

(3) determine the plane equation ax+by+cz=1 on its plane, place according to the coordinate figure of 3 of A, B, C;

(4) calculate vertical three Z, the amount of exercise of θ x, θ y according to the geometric relationship of known plane and space coordinates.

(5) level 2 amounts of exercise of D, E on two laser interferometer measurement worktable of x axle along the x axle, according to measured some amount of exercise and DE pitch geometry, the evaluation work platform is along the amount of exercise X of x axle with along the rotational angle theta z of z axle, and considers that θ z is to influence that X produced.

(6) the F point is along the amount of exercise of y axle on laser interferometer measurement worktable of y axle for level, and according to F point amount of exercise and rotational angle theta z, the evaluation work platform is along y axle amount of exercise Y, and considers that θ z is to influence that Y produced.

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