JPH08114429A - Device and method for detecting rotational deviation of object using cyclic pattern - Google Patents

Abstract

PURPOSE: To measure the rotational deviation of an object in high accuracy by directing a laser light onto a cyclic pattern prepared on the object. CONSTITUTION: An object 1 to be tested is placed on a sample table 10 and the pitch direction of diffraction grid 2 prepared on the object 1 is aligned with a reference direction x, then the table 10 is shifted by using x and y stages 14 and 12 so that a light beam 3 may be directed to a grid 2. ±n-th diffracted lights 5 and 6 of the grid 2 irradiated by the beam 3 are made incident into the point symmetry points 8 and 9 on the surface that is vertical against a 0-th diffracted light 4 of light detecting means 17 and 18. A straight line connecting both positions 8 and 9 is parallel to the direction x when an angle ωz of rotational deviation against z-axis is zero. When the object 1 generates the deviated angle ωz, the lights 5 and 6 are turned into diffracted lights 5' and 6' according to rotational angle, which are made into positions 8' and 9'. The means 17 and 18 output electric signals according to the incident position, and differences Sn and S-n between the positions 8' and 9' and the positions 8 and 9 are measured in high resolution by an arithmetic means 19. Thus, the rotational deviation of an object can be detected in high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation deviation detecting method and a rotation deviation detecting device using the same, and provides a periodic pattern on a part of an object to be inspected, and utilizes diffracted light from the periodic pattern. , For example, a microscope sample table for detecting the rotational deviation of the object to be inspected, a hologram setting EB drawing device, an exposure device,
The present invention relates to a rotation deviation detection device suitable for an overlay evaluation device, a rotary encoder, and a yawing inspection device.

[0002]

2. Description of the Related Art Conventionally, for example, an object to be inspected is placed on a sample stand of a microscope, and a feeding direction and a rotation deviation of the sample stand when successively observing a minute area of the inspected object are detected, and the object is placed at a regular position. Various correction devices have been proposed. In this case, generally, the rotational deviation is corrected while observing the patterns on both ends in the feeding direction of the test object.

An apparatus for detecting a rotational displacement of an object by image-processing a predetermined pattern is disclosed in, for example, Japanese Patent Laid-Open No. 60-
It is proposed in Japanese Patent No. 77273. A rotary encoder is proposed as a device for detecting the rotational deviation of the object to be inspected with high accuracy, for example, in Japanese Patent Laid-Open No. 61-66926.

In addition to the above, as a method for measuring the positional deviation of the object to be inspected, firstly, there is a method in which a pattern for measurement is printed and the deviation between the patterns is measured by a pattern line width measuring device.

Secondly, there is a vernier system in which gratings having different pitches are printed on an integrated circuit and the portions of the gratings that exactly overlap are read. Thirdly, there is a method of forming a long thin resistor and an electrode on an integrated circuit so as to overlap each other and comparing respective values of the resistor.

Fourthly, the applicant of the present invention is disclosed in Japanese Patent Laid-Open No. 4-2120.
There is a method of printing a diffraction grating on an integrated circuit and measuring the amount of deviation of the pattern by the phase difference of the diffracted light as proposed in Japanese Patent Laid-Open No.

Next, a fourth method among the above-mentioned methods for reference will be described.

FIG. 23 is an explanatory view showing the detection principle of the positional deviation detecting device proposed in the publication.

In FIG. 23, two linear gratings (gratings) A'and B ', which are provided on the object and are on the same plane and adjacent to each other, are considered. Here 'equally, the mutual grating shifted in the arrow direction (x direction) (Δx = x _B' pitch of the two gratings together P -x
_A ') has occurred.

[0010] If the one of the grating A ', the other end B' and (X _A ', X _B' is, x-direction deviation from the same reference position of each grating A ', B').

Here, the frequency is slightly different (ω _f1 ,
omega _f2), the initial phase, respectively _φ 0f1, 2 two optical 109 and 110 phi _0F2 is to incident on the grating A ', B'. At this time, the complex amplitudes E _f1 and E _f2 of the two lights 109 and 110 are E _f1 = A ₀ exp {i (ω _f1 t + φ _of1 )} (1) E _f2 = B ₀ exp {i (ω _f2 t + φ) _of2 )} ... (2) The two lights 109 and 110 are applied to the entire surfaces of the two gratings.

For example, the light 109 is emitted from the left and the light 110 is emitted from the right at the incident angles of the same absolute value. At this time,
The + 1st-order diffracted lights of the light 109 with respect to the gratings A ′ and B ′ are 111 and 112, and the −first-order diffracted lights of the light 110 with respect to the gratings A ′ and B ′ are 113 and 114.
And

[0013] and each the light and complex amplitude displays the complex amplitude of the light 111,113,112,114 each _{E 'AF1 (+1), E} ' AF2 (-1), E 'Bf1 (+
1) and E ′ _Bf2 (−1), E ′ _AF1 (+1) = A _f1 exp {i (ω _f1 t + φ _of1 + φ _A ′)} (3) E ′ _AF2 (−1) = A _f2 exp { i (ω _f2 t + φ _of2 + φ _A ′)} (4) E ′ _Bf1 (+1) = B _f1 exp {i (ω _f1 t + φ _of1 + φ _B ′)} (5) E ′ _Bf2 (−1) = B _f2 exp {i (ω _f2 t + φ _of2 + φ _B ′)} (6)

Here, φ _A ′ = 2π × _A ′ / P, φ _B ′
= 2πx _B ′ / P, and the shift amounts of the gratings A ′ and B ′ in the x direction are expressed as phase amounts.

Diffracted light 1 from the grating A '
When the diffracted lights 11 and 113 and the diffracted lights 112 and 114 from the grating B ′ are caused to interfere with each other, the respective interference light intensity changes I _A and I _B are as follows.

I_A = | E '_Af1 (+1) + E '_Af2 (-1) |² = A² _f1+ A² _f2+ 2A_f1A_f2・ Cos {2π (f₂ -F₁ ) T + (φ_of2 −φ _of1 ) -2φ_A ′}… (7) I_B = | E '_Bf1 (+1) + E '_BF2 (-1) |² = B² _f1+ B² _f2+ 2B_f1B_f2・ Cos {2π (f₂ -F₁ ) T + (φ_of2 −φ _of1 ) -2φ_B ′}… (8) where f₁ = Ω_f1/ 2π, f₂ = Ω_f2/ 2π, A² _f1 +
A² _f2 , B² _f1 + B² _f2 Is the DC component, 2A_f1A_f22B
_f1B_f2Is the amplitude. Equations (7) and (8) are f₂ -F₁ 
Signal with the beat frequency component of_of2 
−φ_of1 And the individual shift amounts of the gratings A'and B '
φ_A ′, Φ_B ′ Becomes a form that is phase-modulated in time.
ing.

Therefore, the initial phase of the light can be erased by detecting two time lags with one of the signals represented by the equations (7) and (8) as the reference signal and the other as the signal under measurement. Highly accurate phase detection is possible as so-called heterodyne interferometry.

(Δφ = 2 (φ _B ′ −φ _A ′) = (4π / P ′) Δx)

As described above, the optical heterodyne interferometry has two
Since the phase shift between two signals is detected as time, even if there is a difference in DC component or a change in amplitude between signals, it does not affect the measurement.

Here, as shown in FIG. 24, the reference signal 11
5. Let ΔT be the time shift of the signal under measurement 116, then Δ
The phase difference can be measured with high accuracy by detecting T with high accuracy using, for example, lock-in.

Since the phase difference detected as described above has a value of the phase difference Δφ indicating the shift amount Δx between the gratings, the shift amount Δx between the gratings can be obtained from P ′ × (Δφ / 4π).

Therefore, if the shift amount Δx between the grating pattern printed in the first time and the grating pattern printed in the second time is calculated based on the above-described principle, for example, the alignment accuracy of the semiconductor exposure apparatus, that is, the first time It is possible to detect the amount of deviation between the actual element patterns formed by the second printing.

[0023]

Among the conventional rotation deviation detecting devices, the method of observing the pattern at both ends of the object to be inspected in the feeding direction is complicated by repeating trial and error. Further, the method based on image processing requires image processing calculation and requires a large apparatus, and is not suitable for highly accurate detection of a minute rotation deviation in terms of processing time and accuracy.

Further, the method using the rotary encoder is complicated because it is necessary to determine the rotation axis in advance, and the rotation axis must be adjusted with high accuracy for high-accuracy measurement.

When the rotation axis is not generally fixed,
For example, when the sample for evaluation is placed on the sample table or when the mask θ alignment system of the semiconductor printing apparatus is used, it cannot be sufficiently dealt with.

Further, according to the method using the first pattern line width measuring device among the methods for detecting the positional deviation of the object to be inspected,
Normally, the accuracy of such an apparatus is only about 0.01 μm. In addition, the second vernier method has a problem in that only accuracy of about 0.04 μm can be obtained.

Further, although the third resistance measuring method can obtain accuracy, it has a problem that it requires a considerably complicated processing step for measuring.

On the other hand, the fourth method is a relatively simple and inexpensive method in consideration of the first and third problems. In the fourth method, as shown in FIGS. 25 and 26, incident light beams 109 and 11 to the measured patterns (diffraction gratings) 53 and 54 are measured.
Of the relative relationship between 0 and the pattern, the following may occur with respect to the fluctuation of the in-plane rotation amount of the wafer 55 and the phase difference Δφ.

FIG. 25 shows a state in which a light beam enters the patterns (diffraction gratings) 53 and 54 for the inspection of FIGS. 25, 26 and 23. The distance between the centers of the patterns 53 and 54 is d, the center point of the pattern 53 is P ₁ , and the center point of the pattern 54 is P ₂
25, the case where the incident angles to the patterns 53 and 54 deviate by θ _Z as shown in FIG.

At this time, as shown in FIG. 26, if the intersection point of the heavy lines from the point P ₁ to the ray entering the point P ₂ is H, and the ray 109 is a plane wave, the positions H and P
₁ is included in the equiphase surface. The ray of light beam 2 entering point P ₁ is 67, and the ray of light beam ₂ entering point P ₂ is 68. Ray 6
If the direction cosine of the traveling direction of 7, 68 is (α, β, γ),

[0031]

[Outside 1] Becomes

Further, in the light flux 110, the ray entering the point P ₁ is 70 and the ray entering the point P ₂ is 71. The complex amplitude display of the first-order diffracted light of the ray 67 is Ea '(f ₁ ) = Aexp {i (ω ₁ t + φ ₁ + φa)} (10) Similarly, the diffracted light of the ray 70, the ray 68, and the ray 71 is displayed in complex amplitude. the _{Ea '(f 2) = Bexp} {i (ω 2 t + φ 2 -φa)} ... (11) Eb' (f 1) = Aexp {i (ω 1 t + φ 1 + φ b + (2π / λ) · βd) } ... (12) Eb '( f 2) = Bexp {i (ω 2 t + φ 2 -φ b - (2π / λ) · βd)} ... (13) here, φ _1, φ ₂ are initial phases, phi _a, phi _b is the position deviation corresponding phase.

Due to the interference of Ea '(f ₁ ) and Ea' (f ₂ ), Ia '= | Ea' (f ₁ ) + Ea '(f ₂ ) | ² = A ² + B ² + 2 · A · Bco s {ω ₁₋ ω ₂ ) t + (φ ₁ −φ ₂ ) + 2φa} (14) Due to the interference of Eb ′ (f ₁ ) and Eb ′ (f ₂ ), Ib ′ = A ² + B ² + 2 · A · B cos {ω ₁ −ω ₂ ) t + (φ ₁ −φ ₂ ) +2 φb−2 · (2π / λ) · βd} (15)

Therefore, according to the equations (14) and (15), θ _z ≠ 0
If θ _z = 0, that is, if the y component β = 0 of the direction cosine of the incident light 67, 68, the phase changes by (4π / λ) · βd (when β ≠ 0) It will be.

As a result, assuming that the error corresponding to the deviation between the grid patterns 53 and 54 is Δx ′, Δx ′ = 2βd (16), the value corresponding to Δx ′ = 5 nm is β = Δx when d = 100 μm. ′ / (2d) = 5 nm / (2 × 100) μm =
2.5 × 10 ⁻⁵ θ _Z = 90 ° −cos ⁻¹ β = 5.1 ″.

That is, when the value of θ _Z fluctuates by 5.1 ″, the deviation detection value between the grating patterns 53 and 54 changes by 5 nm. This means that the detection optical system and the wafer 55 rotate in the plane of the wafer. 5 nm if there is a corresponding relative variation of 5.1 "
Therefore, it becomes difficult to detect the deviation with high accuracy.

Usually, in an exposure apparatus for manufacturing semiconductor devices, a wafer stage sends a 6-inch or 8-inch wafer. In this case, complicated monitor functions and controls are required to prevent rotation of the second order, and rotation of the second order, that is, yawing, occurs when attempting to achieve stage feed with a simple configuration. It becomes difficult to avoid the deviation detection error between the patterns.

Further, it is difficult to avoid a detection error caused by a local in-plane rotational deviation due to the position of the wafer, which occurs during drawing of the grating pattern, during exposure and during the process.

In view of the above problems, an object of the present invention is to provide a rotation deviation device and method capable of measuring the rotation deviation of an object with high accuracy, and in an apparatus in which the performance of the device is deteriorated by the rotation deviation of the object. An object of the present invention is to provide an apparatus provided with the rotation deviation device.

[0040]

According to one embodiment of an object rotation deviation detecting apparatus of the present invention for achieving the above object, a pattern having periodicity formed on the object, a laser light source, and an incident light beam are provided. And a light beam from the laser light source is incident on the pattern to guide at least two diffracted light beams from the pattern to the detection surface, and a beam waist of the laser light source to the pattern. And an optical system for forming an image between the detection surfaces, based on the incident position of the plurality of diffracted light on the detection surface,
Means for determining a rotational deviation of the object from a predetermined axis.

In particular, the optical system is characterized in that the beam waist is imaged on the pattern.

In particular, the optical system is characterized in that the beam waist is imaged on the detection surface.

In particular, the pattern is a diffraction grating.

In particular, the pattern is a circuit pattern.

Further, the present invention is characterized by further comprising a holding table for holding and rotating the object, and a control means for rotating and moving the holding table based on the rotational deviation obtained by the determining means.

According to one mode of the rotation deviation detecting method for detecting the rotation deviation of the object of the present invention, the step of forming a pattern having a periodicity on the object, and making a light beam from a laser light source incident on the pattern, Guiding at least two diffracted lights from the pattern to the detection surface and forming a beam waist of the laser light source between the pattern and the detection surface; and a step of forming the plurality of diffracted lights on the detection surface. Determining a rotational deviation of the object from a predetermined axis based on the incident position.

In particular, the beam waist is imaged on the pattern.

In particular, the beam waist is imaged on the detection surface.

In particular, the pattern is a diffraction grating.

In particular, the pattern is a circuit pattern.

Further, the method is characterized by further comprising the step of rotationally moving the object based on the rotational shift obtained in the determining step.

[0052]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a basic conceptual diagram for detecting rotation deviation information in a rotation deviation detecting device of the present invention.

In the figure, reference numeral 1 is an object to be detected for detecting rotational deviation information.

In FIG. 1A, a light beam 3 is emitted from a light source means (not shown) to a diffraction grating 2 provided on an object 1. At this time, the diffraction grating 2 produces 0th-order diffracted light 4, nth-order diffracted light 5, and -nth-order diffracted light 6.

Now, as shown in FIG. 1 (A), the coordinate system is such that the normal direction of the diffraction grating 2 on the object 1 is z, the rotation deviation angle with respect to the z axis is ω _z , and the reference direction of the rotation deviation is the direction. x is defined as y, and a direction orthogonal to both is defined as y.

As the diffraction grating 2, a straight grating having an equal pitch is arranged so that the pitch direction is x, the incident surface is set to be the yz plane, and the light beam 3 is irradiated onto the diffraction grating 2. Of the diffracted light from the diffraction grating 2, the 0th-order diffracted light 4 is y−
Specular reflection is performed symmetrically in the z plane with respect to the z axis.

Consider a virtual plane IP (normally a detection surface) that is separated from the center of the diffraction grating 2 by a predetermined distance L and is perpendicular to the 0th-order diffracted light 4. The point 7 is the center point of incidence of the 0th-order diffracted light 4 on the virtual plane IP. Then, the n-th order diffracted light 5 and the −n-th order diffracted light 6 diffracted from the diffraction grating 2 are 0 on the virtual plane IP.
The second diffracted light 4 is present (incident) at positions 8 and 9 which are point-symmetrical at an equal distance R from the incident center point 7.

When there is no rotational deviation, that is, when ω _Z = 0, the straight line connecting points 8 and 9 is parallel to the reference direction x.
Of course, the reference direction may be predetermined. Object 1
Causes a rotational deviation ω _Z , the diffracted lights 5 and 6 become diffracted lights 5 ′ and 6 ′ according to the rotation angle (proportionally), and the diffracted lights 5 and 6 are rotated about the incident point 7 of the 0th-order diffracted light 4 and are respectively point 8 ', 9'
Come to the position.

When the rotational deviation ω _Z is not so large,
The moving direction is orthogonal to the direction connecting the 0th-order diffracted light 4 and the reference-time diffracted lights 5 and 6, and if the moving amounts are S _n and S _-n , respectively, the following equation (17) ω _Z = (S _n − S _−n ) / (2R) ... (17)

Here, the movement amounts S _n and S _−n move in opposite directions according to the rotation deviation. If the distance R is set to be large and the movement amounts S _n and S _n-1 are measured with high resolution, a minute rotation deviation ω _Z of the object 1 can be detected.

If the pitch of the diffraction grating 2 is P, then the relational expression Psin θ ′ = nλ ... (18) tan θ ′ = R / L (19) holds based on the diffraction principle of the diffraction grating.

From equations (18) and (19), R = Ltan θ ′ = Ltan {sin ⁻¹ (nλ / P)} (20), and the distance L to the evaluation surface, irradiation wavelength λ, diffraction order n
Also, it becomes possible to arbitrarily set R by the pitch P of the diffraction grating.

On the other hand, the influence on the movement of the object 1 other than the rotation deviation ω _Z is canceled as described below, and does not result in the detection error of the rotation deviation ω _Z. First, each axis x, y,
The displacement of the object 1 in the z direction will be described.

(A) When the object 1 is displaced by x'in the x-axis direction When the irradiation area of the irradiation beam 3 on the diffraction grating 2 in the x direction is smaller than the diffraction grating 2, the incident point 8 of the diffraction beams 5 and 6 is set. , 9 does not change. When the irradiation area is larger than the diffraction grating 2, the incident points of the diffracted beams 5 and 6 move in the x direction by the same amount. Since it is a direction orthogonal to the detection direction of the rotation deviation ω _z , it does not cause a rotation deviation measurement error.

(B) When the object 1 is displaced by y'in the y-axis direction When the irradiation area of the diffraction grating 2 of the irradiation beam 3 in the y direction is smaller than the diffraction grating 2, the incident points 8 and 9 of the diffraction beams 5 and 6 are obtained.
Does not change. When the irradiation area is larger than the diffraction grating 2, the same amount S proportional to y ′ is detected in the detection direction of the rotation shift ω _Z.
y'move. The rotation deviation detection amount ω _Z is ω _z = {S _n + Sy ′ − (S _−n + S _y ′)} / (2R) = (S _n −S _−n ) / (2R), which is a measurement error of the rotation deviation. Don't

(C) When the object 1 is displaced by z'in the z direction: Regardless of the sizes of the irradiation beam 3 and the diffraction grating 2, the incident points 8 and 9 of the diffracted beams 5 and 6 are detected as the rotational displacement ω _z . Each move in the direction by an amount S _Z ′ proportional to z ′. The rotational deviation detection amount ω _z is ω _z = {S _n + S _Z ′-(S _−n + S _Z ′)} / (2R) = (S _n −S _−n ) / (2R), which is the measurement error of the rotational deviation. Does not mean

Next, the influence of the tilt of the object 1 will be described.

(D) When there is a tilt ω _x ′ corresponding to rotation about the x-axis Regardless of the sizes of the irradiation beam 3 and the diffraction grating 2, the incident points 8 and 9 of the diffraction beams 5 and 6 are The rotation shift ω _{z is} moved in the detection direction by an amount Sω _x ′ proportional to ω _x ′.

The rotational displacement detection amount ω _z is ω _z = {S _n + Sω _x ′ − (S _−n + Sω _x ′)} / (2
R) = (S _n −S _−n ) / (2R), which is not a measurement error of the rotation deviation.

(E) When the tilt ω _y ′ corresponding to the rotation around the y-axis exists, the incident points 8 and 9 of the diffracted beams 5 and 6 are rotated regardless of the sizes of the irradiation beam 3 and the diffraction grating 2. Shift ω _z Moves by the same amount in the direction orthogonal to the detection direction. Rotational deviation ω _z
Since the deviation is orthogonal to the detection direction, it does not cause a rotation deviation measurement error.

In the above, the rotational displacement detection amount ω _z is ± n
It was calculated from the amount of movement of the incident position of the next light on the virtual plane from the reference line.

As shown in FIG. 1B, diffracted lights of other diffraction orders are also incident on the virtual plane, and each diffracted light is incident on a straight line at intervals determined by the pitch of the pattern.

Therefore, even if the ± n-order light is not used, if the movement amount is obtained from the reference line of the incident position of at least two diffracted lights among the diffracted lights located on the straight line, the rotation deviation detection amount ω _z can be obtained. It can be easily seen from FIG. 1 (B).

FIG. 2 is a schematic view of the essential parts of the first embodiment when the rotation deviation detecting device of the present invention is applied to a sample evaluation device.

In this embodiment, the sample stage 1 with a rotary stage is used.
0 sample (wafer, object) 1 is a microscope system evaluation means 2
The case of evaluation from 0 is shown.

In FIG. 2, 2 is a diffraction grating provided on the sample 1, 11 is a rotation control system of the sample stage 10, 12 is a y stage for moving the sample stage in the y direction, and 13 is control of the y stage 12. System, x is for moving the sample table in the x direction
A stage, 15 is a control system of the x stage 14.

Reference numeral 16 is a light irradiating means for a rotation deviation detection system, and 1
Reference numerals 7 and 18 denote detection means (light receiving means) for detecting the incident positions of the light flux (diffracted light), and 19 calculates the rotation deviation of the sample 1 based on the signals from the detection means 17 and 18, and calculates the rotation deviation amount. It is a calculation means for transmitting the rotation control system 11.

Next, a flow of correcting the rotational deviation ω _z of the sample 1 in the above-described configuration and sequentially evaluating the minute area of the sample arranged on the sample 1 by the evaluation means 20 will be described with reference to the flowchart of FIG.

As shown in FIG. 2, first, the reference of the rotation direction is adjusted to the stage feed direction x (this can be done only once during assembly using the microscope system 20 or the like).

Next, the sample 1 is set on the sample table 14. At this time, the in-plane rotational deviation ω _z of the sample 1 exists due to the set error. This rotation deviation amount ω _z is evaluated using the rotation deviation detection system shown below. The light beam 3 emitted from the light irradiation means 16 irradiates the sample 1 through the condenser lens 40.

Next, the sample stage 10 is moved to the stage 1 so that the light beam 3 irradiates the diffraction grating 2 provided on the sample 1.
Use 2 and 14 to move. Irradiation beam 3 and diffraction grating 2
Need only be roughly, and normally, the stages 12 and 14 may be moved to a predetermined position excluding the set error.

Fine adjustment is not necessary, but the detection means 1
The amount of light detected in 7 and 18 is used, and the microscope system 20
It may be adjusted depending on the observation system.

Next, the irradiation beam 3 is diffracted by the diffraction grating 2 to generate m-th order (m is an integer) diffracted light. this house,
The incident positions 8 ', 9'of the two ± n-order diffracted lights 5', 6'having the same absolute value and different signs on the detection means 17, 18 are detected.

The detecting means 17 and 18 are composed of a light position detecting sensor (for example, a two-divided sensor or PSD), and output an electric signal according to the incident position of the light beam.
At this time, the means 17 for detecting the ± n-order diffracted lights 5 ′ and 6 ′,
The computing means 19 finds the differences S _n and S _−n between the incident positions 8 ′ and 9 ′ on the 18 surface and the reference positions 8 and 9 of the light beam to the detecting means 17 and 18.

Differences S _n and S _-n obtained by the calculating means 19
As described above, the rotation deviation correction amount is obtained from ω _z = (S _n −S _−n ) / (2R). A value corresponding to this rotation deviation amount is sent to the rotation control system 11. The rotation control system 11 rotates the sample table 10 based on this value and corrects the rotation deviation of the sample 1.

In this way, the sample rotation deviation is corrected. After this, the evaluation area on the sample 1 is successively evaluated by the evaluation means 20.
The sample is evaluated by setting the stage 12 and 14 so that the sample is evaluated. When the evaluation of the entire Sample 1 is completed, replace the evaluated sample with the sample to be evaluated next,
Evaluation is performed according to the above flow.

In this embodiment, the diffraction grating 2 is set to have a pitch of 2 μm and the projection light beam 3 has a wavelength of 830 nm so as to receive ± 2nd order diffracted light. The diffraction angle at this time is ± 56 °, and the distance L to the evaluation surface of the light receiving system is L = 7.
It is 4.2 mm, and when R = 110 mm, the rotational displacement ω _z detection sensitivity (rotation angle per 1 μm on the sensor surface) is ω _z ′ = 1 / (2 × 110 × 10 ³ ) = 4.5 × 10 ⁻⁶ Since rad = 0.5 ″, the rotation deviation is detected on the order of seconds.

The image forming relationship between the irradiation beam 3, the diffraction grating 2 and the detecting means 17 and 18 is preferably as follows.

The intensity distribution of the beam 3 projected from the light irradiation means 16 is generally in the form of a Kaussian beam, and the beam shape condensed by the lens system 40 is given as follows. The beam radius at the beam waist position is ω _o ,
Assuming that the coordinate of the light traveling direction is u (deviation from the beam waist) and the wavelength is λ, the beam radius ω at the position of u is

[0090]

[Outside 2] When the diffraction grating 2 can be made large enough, the optical position detecting sensors 17 and 18 are placed at the beam waist position as shown in FIG.
Is preferably arranged to minimize the beam diameter on the sensor surface.

In this case, when the distance l ₁ between the grating 2 and the beam waist is set to be a beam waist radius ω ₂₁ , the beam radius ω ₁₁ on the grating surface 2 is

[0092]

[Outside 3] Becomes

In this embodiment, the distance from the actual diffraction grating 2 to the optical position sensors 17 and 18 is l ₁ = 7.
4.2mm, beam waist radius ω ₂₁ = 100μ
If m, then ω ₁₁ = 364 μm.

When the size of the diffraction grating 2 cannot be made too large due to the size of the object, etc., the diffraction grating 2 is arranged at the beam waist position as shown in FIG. _It is preferable to set ₂ appropriately so that the beam on the sensor surface does not spread so much (a range that does not spill from the sensor surface within the detection range). The beam radius ω ₂₂ on the sensor surface at this time is

[0095]

[Outside 4] Becomes

Further, if the size of the diffraction grating 2 cannot be increased so much, but the beam diameters on the optical position sensors 17 and 18 are not desired to be increased too much, the intermediate arrangement between FIG. 4 and FIG. The beam waist position may be set between the diffraction grating 2 and the optical position sensors 17 and 18 as shown in FIG.

FIG. 7 shows a relay lens system 4 in addition to the detection system of FIG.
2, 43 are provided.

As for the image formation relationship, as shown in FIG. 8, the detection surface of the optical position sensor in the image formation relationship of FIG.
It is shifted to a conjugate position by 2 or 43. The relay lens system forms an image at the same size, and the rotation deviation sensitivity and the beam diameter on the sensor surface are equivalent to those in the case of FIG.

9 and 10 show a diffraction grating 2 provided on a sample plate 1 instead of the sample 1 shown in FIG.

In FIG. 9, the diffraction grating 2 is provided at a position away from the position 41 on which the sample is placed.

In FIG. 10, the position 41 on which the sample is placed and the diffraction grating 2 are in the same region. In this case, the diffraction grating 2 has a mesh shape. It is also possible to partition the region on which the sample (sample) is placed into a mesh shape, and also serve as a grid for rotation detection.

FIG. 11 is a schematic view of the essential portions of a second embodiment in which the rotation deviation detecting device of the present invention is applied to an exposure apparatus for manufacturing semiconductor elements.

In this embodiment, the case where the chip rotation of the exposure apparatus is evaluated is shown, and the structures of the light emitting / receiving system, the sample holder system, the arithmetic processing system and the like are the same as those in the first embodiment of the present invention.

FIG. 12 is a flow chart of this embodiment.

In this embodiment, there is no need for initial setting as in the flow chart shown in FIG. A plurality of shots (3 in FIG. 11) were formed on the sample 1 by an exposure device (not shown).
(Shot is shown by dotted line) A, B, C are exposed,
Diffraction gratings 2A, 2B, and 2C are exposed in each shot. These diffraction gratings 2A, 2B,
2C has the same pitch of 2 μm.

The sample 1 is set on the sample table 10, and the stages 12 and 14 are moved so that the diffraction grating 2A shown by shot A comes to the rotation deviation evaluation position.

The light beam 3 from the light irradiation means 16 is condensed through the condenser lens 40 and diffracted by the diffraction grating 2A, and the ± nth order diffracted lights 5 and 6 travel toward the detection means 17 and 18. Then, the ± nth order diffracted lights are incident on the positions 8A and 9A on the surfaces of the detecting means 17 and 18.

In the first shot detection, the position is stored in the arithmetic unit 19, and after the second shot, the shift amount ω _zB from the first position is calculated and converted into the relative rotation shift angle from the shot A. And save. Rotation offset amount omega _zB at this time is _{ω zB = (S nB -S -nB} ) / (2R).

When the rotation deviation measurement is completed for all shots, the relative rotation deviation between the shots of the sample is put together, the sample is made into the chip rotation, the next sample is exchanged, and the same measurement is repeated.

FIG. 13 shows an example of an IC circuit showing a source-drain diffusion pattern layout of a unit cell type MOS-LSI. As is clear from this figure, it is understood that the wiring patterns are arranged in a periodic structure. .

It is also possible to irradiate a beam on such a periodic circuit pattern and perform rotation detection based on the obtained beam position of the ± nth order diffracted light.

FIG. 14 is also an example of an IC circuit, which is an example of a high power transistor having a stripe structure with an increased number of emitters. In the figure, E is the emitter, Ba is the base, and C
o is a collector. Even in such a dot-shaped grating, if there is a periodic structure, ± n-order diffracted light corresponding to the period is generated, so that it can be used.

FIGS. 15 and 16 show the structure of the optical position sensor 17 suitable for detecting the diffracted light of such a circuit pattern and detecting the rotation.

FIG. 15 shows one-dimensional position detectors arranged side by side, and detectors for receiving light are selected according to the cycle of the circuit. The optical position sensor 18 side is also arranged in the same manner, and the corresponding detector detects the diffracted light.

FIG. 16 uses a two-dimensional sensor,
According to the cycle of the circuit, rotation detection is obtained from the beam position in the S direction and rotation detection.

Similar to the detector 17, the detector 18 can also take the corresponding signal and obtain the rotation amount from the two signals.

FIG. 17 is a schematic view of the essential parts of the third embodiment, and FIG. 18 is an enlarged view of the hologram used in the third embodiment.

This embodiment is applied to a Twyman-Green interferometer for aspherical surface inspection using computer holography.

The beam emitted from the laser 80 is expanded by the lenses 81a and 81b and split by the beam splitter 83. One of them is transmitted, further transmitted through the beam splitter 84, once condensed by the lens 85, further becomes divergent light, is guided to the test surface 86, is reflected by the test surface 86, passes through the lens 85 again, and then the beam splitter 84.
Is reflected by and is condensed by the lens 89. The other light split by the beam splitter 83 is reflected by the beam splitter 83, and is irradiated onto the hologram pattern portion 45 of the hologram 44 via the mirrors 87 and 88. The reference wavefront generated here passes through the beam splitter 84,
The light is condensed by the lens 89, unnecessary light is removed by the spatial filter 90, and is guided to the observation surface 91 together with the beam from the test surface to form interference fringes.

This is used when evaluating an aspherical surface having a relatively large amount of aspherical surface.

At this time, when setting the hologram 44, the rotation of the hologram becomes a problem, and it is essential to detect the rotation amount with high accuracy.

In this embodiment, as shown in FIG.
The diffraction grating 2 for rotation detection is arranged in the hologram 44,
This is used to accurately set the hologram.

The rotation detection system irradiates the beam emitted from the light source 16 to the diffraction grating 2 on the hologram 44 by the lenses 40a and 40b, and detects the ± n-order diffracted light generated by the optical position sensors 17 and 18.

The rotation amount detecting method is the same as that shown in the first embodiment.

The fourth embodiment according to the present invention is applied to filtering by a Fourier transform hologram and is also applied to image processing, matched filtering and the like.

In the case of Fourier transform holography,
U, V, and W are given by the Fourier transform of the objects u, v, and w, respectively, and the output image r (x _i , y) of the filtering is given.
_i ) is the Fourier transform of the filter transmitted light T '(x, y).

R (x _i , y _i ) = F [T ′ (x, y) = F [k ₀ W + k ₁ W (| U | ² + | V | ² )] + F [k ₁ WU ^* V] + F [K ₁ WUV ^* ] The second and third terms form ± 1st order output images r ₊₁ and r _-1 ★ and *
Where r ₊₁ (x _i , y _i ) = F [k ₁ WU ^* V] = const
・ {(U ^* ★ w) * v} r ₋₁ (x _i , y _i ) = F [k ₁ WUV ^* ] = const
There is a relationship of {(u * (w ★ * v ^* )}, where r ₊₁ represents the mutual relationship between u ^* and w and the convolution of v, and r ₋₁ represents the mutual correlation between v ^* and w. u
Represents the convolution with.

As a special case, if u is a reference point light source on the axis as shown in FIG. 19 and there is an object v centered at a point distant from b in the x ₀ direction, u (x ₀ , y ₀ ) = δ
(X ₀ , y ₀ ), v ′ (x ₀ , y ₀ ) = v (x ₀ −b,
y ₀ ), U (x, y) = 1, V ′ (x, y) = V (x,
y) exp (-ibx), the amplitude transmittance of the hologram is T (x, y) = k ₀ + k ₁ + k ₁ | V | ² + k ₁ Vex
_{p (-ibx) + k 1 V} * exp (ibx) which is the Fourier transform hologram of an object V. FIG.
As shown in Fig.3, in filtering, if this hologram is used as a filter and ω is given as an input object on the axis, the + 1st-order and -1st-order output images by the hologram are the convolution of w and v and the cross-correlation of w and v ^* . Becomes

R ₊₁ (x _i , y _i ) = F [k ₁ WV] = c
onst · {w (x _i , y _i ) * v (x _i −b ,, y
_i )} r ₋₁ (x _i , y _i ) = F [k ₁ WV ^* ] = const ·
{W (x _i , y _i ) ★ v ^* (x _i + b ,, y _i )} Therefore, if w is the same as v, self-convolution and auto-correlation of v are obtained on the output image plane. It is applied to image processing, matched filtering, etc.

At this time, it is necessary to set the hologram 44 with no setting error, particularly with no rotation error.

In this embodiment, the rotation detection system is provided as in the first embodiment.

The light beam from the light source 16 is converted into the hologram 44.
Directly irradiate the obtained diffracted light to the optical position sensor 17,
Detect at 18.

As shown in FIG. 21, the hologram 44 has minute rectangular apertures arranged periodically in a matrix. As shown in FIG. 22, the areas (cells) divided into each matrix correspond to the amplitude and phase of each cell with the size of the window and the distance ε of the window from the cell center. In FIG. 21, rectangular openings having an equal pitch are formed in the vertical direction. Therefore, it suffices to generate diffracted light of ± nth order at a diffraction angle matched to this period and detect them.

The determination of the rotation angle is the same as in the first embodiment.
A hologram (not shown) is created based on the calculated rotation shift amount.
By correcting the rotation control system, the hologram 44 can be set without rotation error.

FIG. 27 is a schematic view of the essential portions of Embodiment 5 of the rotation deviation detecting device of the present invention.

The present embodiment shows a case where the relative positional deviation amount of the two diffraction gratings printed on the wafer is detected with high accuracy and the relative alignment between the mask and the wafer is performed.

In FIG. 27, an x stage 233, ay stage 234 and a θ stage 235 are installed on a surface plate 231, and a wafer 236 is placed on the θ stage 235. As shown in FIG. 28, the wafer 236 is provided with a plurality of overlay error measurement marks, each pair including two adjacent diffraction gratings 253 and 254. Above the surface plate 231, there is a surface plate 232 supported by columns.
An optical system 2 for measuring an overlay error is placed on the surface plate 232.
38 (hereinafter, optical system 238) is arranged.

FIG. 29 is a schematic diagram of the positional deviation detecting portion of the optical system 238 of FIG.

In FIG. 29, the optical system 238 is the phase difference system 2.
62 and the arithmetic unit 263.

In FIG. 29, a mirror 25 is provided in the emitting direction of a light beam from a light source 250 composed of a dual frequency linearly polarized laser.
1, a collimator lens 252 and a prism 227 are arranged. A wafer 255 having two diffraction gratings 253 and 254 as shown in FIG. 28 is placed in the outgoing direction of the prism 227. A mirror 256, a lens 257, a Glan-Thompson prism 258, and a glass portion 259a as shown in FIG. 30 are arranged in the reflection direction of the light flux from the wafer 255.
And an edge mirror 259 having a mirror portion 259b, a lens 260, and a photodetector 261 are arranged.
Is output to the calculator 263 through the phase difference meter 262. Further, the lens 2 is arranged in the reflection direction of the edge mirror 259.
64 and the photodetector 265 are arranged, and the output of the photodetector 265 is connected to the phase difference meter 262.

Light Source 25 Consisting of Dual Frequency Linearly Polarized Laser
The s-polarized light of frequency f ₁ and the p-polarized light of frequency f ₂ emitted from 0 are reflected by the mirror 251, and enter the prism 227 via the collimator lens 252.

The s-polarized light beam having the frequency f ₁ is reflected by the polarization beam splitter 227a of the prism 227, and the p-polarized light beam having the frequency f ₂ is transmitted.
It is reflected by b and 227c, is emitted from the prism 227, and is incident on the diffraction gratings 253 and 254 on the wafer 255.
Then, it is diffracted by the diffraction gratings 253 and 254 to become diffracted light.

Diffraction gratings 253 and 254 on the wafer 255.
Are two adjacent equidistant linear diffraction gratings formed separately on the wafer 255 through the baking process, and their pitches are both equal to p.

As shown in FIG. 28, a positional deviation Δx at the time of printing occurs in the x direction between the diffraction gratings 253 and 254. At this time, first-order diffraction light Ea left incident light of a frequency f ₁ by the diffraction grating 253 (f ₁₎ and the right incident light frequency f ₂ -1 order diffraction light Ea (f ₂₎ complex amplitude display the next (21 ) And (22).

Ea (f ₁ ) = Aexp {i (ω ₁ t + φ ₁ + φa)} ... (21) Ea (f ₂ ) = B exp {i (ω ₂ t + φ ₂ −φa)} ... (22)

Here, A and B are amplitudes, ω ₁ and ω ₂ are angular frequencies, φ ₁ and φ ₂ are initial phases of the light flux emitted from the light source 250, φa = 2πxa / P, and xa is from the reference phase. The amount of displacement of the diffraction grating 253 in the x direction is shown.

Further, the complex amplitude display of the first-order diffracted light Eb (f ₁ ) of the left-side incident light of the frequency f1 and the −1st-order diffracted light Eb (f ₂ ) of the right-side incident light of the frequency f ₂ by the diffraction grating 254 is as follows. ) And (24).

Eb (f ₁ ) = Aexp {i (ω ₁ t + φ ₁ + φb)} ... (23) Eb (f ₂ ) = Bexp {i (ω ₂ t + φ ₂ −φb)} ... (24)

Here, φb = 2πxb / p, and xb
Represents the amount of deviation of the diffraction grating 254 from the reference position in the x direction.

The light beams diffracted by the diffraction gratings 253 and 254 are reflected by the mirror 256, pass through the lens 257 and the Glan-Thompson prism 258, the polarization planes of the diffracted light are aligned by the Glan-Thompson prism 258, and the heterodyne interference occurs. Each heterodyne interference light Ea (f ₁ )
And Ea (f ₂ ) and Eb (f ₁ ) and Eb (f ₂ ) change in light intensity Ia, Ib, that is, the beat signal is the following (25),
It becomes like the formula (26).

Ia = A ² + B ² + 2A · Bcos {(ω ₁ −ω ₂ ) t + (φ ₁ −φ ₂ ) +2 φa} ... (25) Ib = A ² + B ² + 2A · B cos {(ω ₁ −ω ₂ ) t + (φ ₁ −φ ₂ ) +2 φb} (26) The two diffraction interference lights may be separated as follows. That is, since the two diffracted interference lights are slightly separated spatially, the boundary line Ta between the glass portion 259a and the mirror portion 259b shown in FIG. The diffraction light from the diffraction grating 253 is set so as to reach the center of the edge mirror 2.
59 and reflected through lens 264 to photodetector 265
And the diffracted light from the other diffraction grating 254 passes through the edge mirror 259 and passes through the lens 260 to the photodetector 2.
Lead to 61.

The beat signals detected by the photodetectors 265 and 261 are introduced into the phase difference meter 262 to detect the phase difference. When the phase difference is Δφ, Δφ is given by the following equation (27).

Δφ = 2 (φa−φb) = 4π (xa−xb) / p (27) That is, the relative shift amount Δx of the diffraction gratings 253 and 254 in the x direction.
Becomes the following expression (28).

Δx = xa−xb = Δφ · p / 4π (28) Therefore, the output Δφ of the phase difference meter 262 is introduced into the calculator 263 to perform the calculation of the formula (28), and thus the diffraction grating 2
The relative shift amount of 53, 254 can be obtained.

In this way, the alignment amount of the semiconductor exposure apparatus, that is, the first and second exposures, is obtained by determining the amount of deviation between the first and second exposures. The amount of deviation between the actual element patterns formed by baking is detected.

FIG. 31 is a schematic diagram of a rotation deviation correction unit of the optical system 238 of FIG.

This embodiment is different from Embodiment 1 of FIG. 2 in that the diffraction grating 2a on the surface of the wafer 1 is printed by the nth exposure and the diffraction grating 2 is printed by the (n + 1) th exposure.
b is used as a detection pattern of the overlay deviation amount, and the microscope 20 is removed, and an image processing alignment system 225, a television monitor 226, and a system control system 300 are newly provided in place of the microscope 20. The other configurations are the same.

In this embodiment, the flow from setting the wafer 1 on the sample table 10 to detecting the in-plane rotational deviation and correcting the deviation, and the measuring system are the same as in the first embodiment.

The present embodiment is characterized in that the image processing method is used as the overlay deviation evaluation.

The diffraction grating patterns 2a and 2b for overlay shift verification are imaged by the image processing alignment system 225 on the light receiving surface as images 2a 'and 2b' as shown in FIG. Converted to system control system 3
Sent to 00.

Image processing is performed in the system control system 300, and the diffraction grating pattern image 2 for each overlay deviation test is performed.
The center position of each of a'and 2b 'in the x direction is obtained, and the overlay deviation amount is obtained from the difference Δx.

When obtaining the centers of the diffraction grating pattern images 2a 'and 2b', first remove the ones at both ends of the diffraction grating, find the position of each diffraction grating fringe, and calculate the amount of deviation from the reference position of each fringe. It is calculated by taking out and averaging.

As described above, in the fifth embodiment, the diffraction grating pattern on the wafer is irradiated with the light beam, and the diffracted light generated from the diffracted light of the ± nth order (n is a positive integer) is directed onto the predetermined surface. The beam position at the time of incidence is detected, the in-plane rotation amount is detected from this position, and based on this, the in-plane rotation displacement is controlled so that the overlay displacement is measured.

As a result, the error due to the in-plane rotational deviation is removed, and the overlay deviation is measured with high accuracy. Further, since the pattern itself for measuring the overlay deviation is used without adding a pattern for performing in-plane rotation correction, there is an effect that a narrow pattern area can be effectively used.

[0165]

As described above, according to the present invention, it is possible to detect at least two diffracted lights from a pattern by merely providing a pattern having one periodicity on the target object. It is possible to achieve a rotation deviation detection device that can detect rotation deviation with high accuracy.

[Brief description of drawings]

FIG. 1 is a basic conceptual diagram of rotation deviation detection according to the present invention.

FIG. 2 is a schematic view of a main part of the first embodiment of the rotation deviation detecting device of the present invention.

FIG. 3 is a flowchart of the first embodiment of the present invention.

FIG. 4 is a diagram showing a positional relationship between a laser beam waist and a detection sensor.

FIG. 5 is a diagram showing a positional relationship between a laser beam waist and a diffraction grating.

FIG. 6 is a diagram showing a positional relationship among a laser beam waist, a detection sensor, and a diffraction grating.

FIG. 7 is a schematic diagram of a main part showing a modified example of the first embodiment.

FIG. 8 is a diagram showing the image formation relationship of FIG. 7;

FIG. 9 is a diagram showing a diffraction grating provided on a sample.

FIG. 10 is a diagram showing a diffraction grating provided in the same region as a sample.

FIG. 11 is a schematic view of the essential portions of Embodiment 3 of the rotation deviation detecting device of the present invention.

FIG. 12 is a flowchart of Embodiment 3 of the rotation deviation detecting device of the present invention.

FIG. 13 is a diagram showing an IC circuit.

FIG. 14 is a diagram showing an IC circuit.

FIG. 15 is a diagram showing an optical position sensor for detecting diffracted light of a circuit pattern.

FIG. 16 is a diagram showing an optical position sensor for detecting diffracted light of a circuit pattern.

FIG. 17 is a schematic view of a main part of the third embodiment.

18 is a hologram used in Example 3. FIG.

FIG. 19 is a diagram showing a method of creating a hologram.

FIG. 20 is a diagram showing that auto-correlation is obtained on the output image plane.

21 is a diagram showing the hologram 44 of FIG. 20. FIG.

FIG. 22 is a diagram showing a positional relationship between cells and windows.

FIG. 23 is an explanatory diagram on an object plane according to a conventional misregistration detection device.

FIG. 24 is an explanatory diagram of an output signal from the light receiving unit according to the conventional positional deviation detecting device.

FIG. 25 is an explanatory diagram showing a relationship between a diffraction grating and a light flux according to a conventional positional deviation detecting device.

FIG. 26 is an explanatory diagram showing a relationship between a diffraction grating and a light flux according to a conventional positional deviation detecting device.

FIG. 27 is a schematic view of the essential portions of Embodiment 5 of the misalignment detection device of the present invention.

28 is an enlarged explanatory view of a part of FIG. 27. FIG.

FIG. 29 is an explanatory diagram of a part of FIG. 27.

FIG. 30 is an explanatory diagram of a part of FIG. 29.

31 is an explanatory diagram of a part of FIG. 14. FIG.

32 is an enlarged explanatory view of a part of FIG. 18. FIG.

[Explanation of symbols]

 1 Object to be inspected 2 Diffraction grating 3 Light beam 4 0th-order diffracted light 5 nth-order diffracted light 7-nth-order diffracted light 7 Position of 0th-order diffracted light 9- Position of n-th-order diffracted light 10 Sample stage 11 Rotating stage 12 y Stage 13 y Stage drive system 14 x Stage 15 x Stage drive system 16,250 Light projecting means 17, 18 Light detecting means 19 Computing means 20 Evaluation means 21, 22, 253, 254 Diffraction grating 23 Mask 24 IC circuit 25 Diffraction grating 26 Rotation stage 27 Mask holder 28 Wafer 29 Wafer stage 30 Control system 31 Projection means 32, 33 Detection means 34 Calculation means 35 Light beam 36, 37 Diffracted light 38, 39 Position of diffracted light 40a, 40b Lens 44 Hologram 45 Hologram pattern part 80 laser 81a, 81b, 85 lens 83, 4 the beam splitter 86 the test surface 90 a spatial filter 91 observation plane

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G01B 11/00 G G06T 7/00 H01L 21/027 21/68 F H01L 21/30 525 A 541 K

Claims (12)

[Claims] 1. A rotation deviation detecting device for detecting a rotation deviation of an object, comprising: a pattern having periodicity formed on the object; a laser light source; detecting means for detecting a position of an incident light beam; and the laser light source. An optical system that causes a light beam from the laser beam to enter the pattern, guides at least two diffracted lights from the pattern to the detection surface, and forms a beam waist of the laser light source between the pattern and the detection surface. ;
Means for determining a rotational deviation of the object from a predetermined axis based on the incident positions of the plurality of diffracted lights on the detection surface. 2. The rotation deviation detecting device according to claim 1, wherein the optical system forms an image of the beam waist on the pattern. 3. The rotation deviation detecting device according to claim 1, wherein the optical system forms an image of the beam waist on the detection surface. 4. The rotation deviation detecting device according to claim 1, wherein the pattern is a diffraction grating. 5. The rotation deviation detecting device according to claim 1, wherein the pattern is a circuit pattern. 6. A holding base for holding and rotating the object, and a control means for rotating and moving the holding base on the basis of the rotational deviation obtained by the determining means. Item 1. A rotation deviation detection device according to item 1. 7. A rotation deviation detecting method for detecting a rotation deviation of an object, the method comprising: forming a pattern having periodicity on the object; causing a light flux from a laser light source to enter the pattern.
Guiding at least two diffracted lights from the pattern to a detection surface and focusing the beam waist of the laser light source between the pattern and the detection surface; and on the detection surface of the plurality of diffracted lights. Based on the incident position of
And a step of determining a rotational deviation of the object from a predetermined axis. 8. The method according to claim 7, wherein the beam waist is imaged on the pattern. 9. The method according to claim 7, wherein the beam waist is imaged on the detection surface. 10. The rotation deviation detecting method according to claim 7, wherein the pattern is a diffraction grating. 11. The rotation deviation detecting method according to claim 7, wherein the pattern is a circuit pattern. 12. The rotation deviation detecting method according to claim 7, further comprising the step of rotating the object based on the rotation deviation obtained in the determining step.