JP3493329B2 - Planar shape measuring device, planar shape measuring method, and storage medium storing program for executing the method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar shape measuring apparatus, a planar shape measuring method, and a storage medium storing a program for executing the method, and more particularly to measuring the planar shape of an object to be measured using a phase shift method. The present invention relates to a planar shape measuring device, a planar shape measuring method, and a storage medium that stores a program for executing the method.

[0002]

2. Description of the Related Art Conventionally, as a method for measuring the plane shape of an object to be measured, there is a method of measuring the plane shape of the object to be measured by a non-contact method using a phase shift method. In this phase shift method, a part of the light emitted from the light source is reflected by the reference surface, and the other part of the light is reflected by the surface to be measured of the object to be measured, and the reflected image from the reference surface and the object to be measured Interference with the reflection image from the surface to be inspected causes interference fringes, and then the imaging device performs at least three interference fringe images from the surface to be inspected while performing phase shift by a predetermined phase shift amount. It is to get information.

The interference fringe image information is the light intensity of the interference fringes.
It can be represented by I (x, y). Specifically, x, y are x-y coordinates of the surface to be inspected, φ (x, y) is a phase, and δ _i is a phase shift amount. I _i (x, y) = I _B (x, y) + I _A (x, y) cos [φ (x, y) + δ _i ], and the interference fringe image information is the phase shift amount δ _i Changes sinusoidally with respect to. Here, assuming that the phase shift is performed only for α and β with respect to the initial position (δ ₁ = 0), substituting δ ₁ = 0, δ ₂ = α, δ ₃ = β for δ _i in the above equation , I ₁ (x, y) = I _B (x, y) + I _A (x, y) cos [φ (x, y)] I ₂ (x, y) = I _B (x, y) + I _A (x, y) cos [φ (x, y) + α] I ₃ (x, y) = I _B (x, y) + I _A (x, y) cos [φ (x, y) + β ] Is obtained. At this time, the phase φ (x, y) is

[0004]

[Equation 1]

It is represented by

The plane shape of the object to be measured is at least three pieces of interference fringe image information I ₁ (x, y), I ₂ (x, y), and I ₃ (x, which are obtained by the phase shift method as described above. It is calculated by analyzing y) using a known plane shape analysis method.

As a method of performing the above phase shift, 1)
Optical path length variable method for physically changing the optical path length by a minute amount by moving the reference surface, 2) Wavelength variable method for minutely changing the wavelength of the light source while keeping the optical path length constant, 3) Imaging system using a plurality of imaging devices There are multiple spectroscopic methods etc. in which phase shift means is provided in the optical path of the optical path. Phase shift error due to various physical factors δ _i
Δφ tends to occur. In either case, due to these phase shift errors Δφ, desired accuracy cannot be obtained when measuring the planar shape.

Specifically, the phase shift error Δφ with respect to the phase shift amount δ _i is approximately Δφ = a + b · cos (2φ, where a and b are constants according to the algorithm and the amount of phase shift error. ) Is known ("Linear approximation fo
r measurement errorsin phase shifting interferomet
ry "Johannes van Wingerden et al., Applied Optics,
30, 2728-2729 (1991)). In this way, the phase shift error Δφ that fluctuates with the cycle of 1/2 and the amplitude b is the phase shift amount.
It is added to δ _i as an analysis error.

[0009] The phase shift error Δφ, as shown in FIG. 6, when the I _i (x, y) phase shift [delta] _i in formula is an amount necessary for analysis, phase shift [delta] _i is α , 2
Phase shift error ε, 2ε, 3 as α, 3α increases
It increases proportionally like ε.

Thus, the phase shift amount δ _i to be substituted in the equation of the interference fringe image information I _i (x, y) in the phase shift method.
Is a preset fixed value such as 0, α, and β, so that the value is between the actual phase shift amount due to the unstable wavelength of the light source or the occurrence of temperature drift. An error occurs, which causes the phase shift error Δφ to occur as a result.

[0011]

However, conventionally, dedicated hardware is used to acquire the phase shift amount δ _i , and the phase shift amount δ _i measured by the hardware is desirable. It did not have accuracy. The dedicated hardware referred to here is, for example, 1) in the optical path length variable phase shift method, a voltage measuring device that measures the voltage applied to the reference mirror micro displacement mechanism by the displacement mechanism control device of the reference mirror (reference plane), 2) In the wavelength tunable phase shift method, a voltage device that measures the voltage applied to the light source by the wavelength control device. 3) In the multiple spectroscopic phase shift method, the light from the light source passes through individual optical paths by multiple spectroscopic optical systems. It is a phase difference detection device that obtains a relative phase difference in each optical path.

An object of the present invention is to provide a plane shape measuring apparatus, a plane shape measuring method, and a plane shape measuring apparatus capable of accurately measuring a plane shape by accurately acquiring a phase shift amount in a phase shift method without using dedicated hardware. It is to provide a storage medium storing a program of the method.

[0013]

[0014]

[0015]

[0016]

[0017]

In order to achieve the above object, the plane shape measuring apparatus according to claim 1 has a first optical reflection image from the observation surface of the object to be measured and a second optical reflection image from the reference surface. An interference optical system that interferes with the optical reflection image, a phase shift unit that performs a phase shift of the optical phase of the interference fringe image generated by the interference with at least three phase shift amounts, and the at least three phase shift amounts. an interference fringe image acquiring means for acquiring at least three interference fringe images whose phase is shifted, the interference fringe image acquired by the acquisition means the least three interference Shimaga image or al calculation means for calculating the shape of the observation surface in planar shape measuring apparatus including bets, said calculating means comprises first measuring means for measuring the phase of one cycle of the phase of (2 [pi) from one of the acquired interference fringe image, at least Second for measuring a first relative movement amount between one another one of the acquired interference fringe image
Measuring means, and at least third measuring means for measuring a second relative movement amount between one of the acquired interference fringe images and the other one, and at least the acquired interference fringes. First calculating means for calculating a phase shift amount between one of the images and another one from the phase of one cycle (2π) of the measured phase and the measured first relative movement amount. And at least a phase shift amount between one of the acquired interference fringe images and another one of the acquired interference fringe images and a phase of one cycle (2π) of the measured phase and the second measured value.
And a second calculating means for calculating the relative movement amount of the second moving amount.

According to the planar shape measuring apparatus of the first aspect, at least three interference fringe images having different phase shift amounts are acquired, and one cycle (2π) of the phase is acquired from one of the acquired interference fringe images. , And at least a first amount of relative movement between one of the acquired fringe images and one of the other, and at least between one of the acquired fringe images and one of the other. a second relative movement amount is measured, small
At least, the phase shift amount between one of the obtained interference fringe images and the other one is calculated from the phase of one cycle (2π) of the measured phase and the first relative movement amount, and at least ,
Since the phase shift amount between one of the obtained interference fringe images and the other one is calculated from the phase of one cycle (2π) of the measured phase and the second relative movement amount, The planar shape can be accurately measured by acquiring the phase shift amount in the phase shift method with high accuracy without using hardware.

The planar shape measuring apparatus according to claim 2 wherein the claim in the planar shape measuring apparatus according 1, wherein the relative movement amount of the measured <br/> first and second relative to the measured Transfer
Each momentum, a plurality of transfer which are respectively acquired at a plurality of observation positions on Watarushima that interference put on the obtained interference fringe image
Characterized in that it consists of the mean value of the rotation amount.

According to the planar shape measuring apparatus according to claim 2, wherein each of the first relative movement amount and the second relative movement amount is more on Watarushima interference that put the acquired interference fringe image The interference fringe images obtained are not parallel to each other because they consist of the average value of multiple movements obtained at each observation position.
Even in such a case, the predetermined phase shift amount can be acquired accurately.

According to a third aspect of the present invention, there is provided a planar shape measuring method, which comprises an interference step of causing a first optical reflection image from an observation surface of an object to be measured and a second optical reflection image from a reference surface to interfere with each other. Phase shift step of performing phase shift of the optical phase of the interference fringe image caused by interference with at least three phase shift amounts, and interference for obtaining at least three interference fringe images phase-shifted with the at least three phase shift amounts. a fringe image acquiring step, the planar shape measuring method and a calculation step of calculating the interference fringe image corresponding acquired by the acquiring step at least three interference Shimaga image or et shape of the observation surface, the calculating step, A first measurement step of measuring a phase of one cycle (2π) of a phase from one of the acquired interference fringe images, and at least one of the acquired interference fringe images.
Second measuring step of measuring a first relative movement amount between the one and another one, and at least a second relative step between one of the acquired interference fringe images and still another one. A third measurement step of measuring a movement amount, and at least a phase shift amount between one of the acquired interference fringe images and another one of the measured phase and a phase of one cycle (2π) of the measured phase. A first calculation step of calculating from the measured first relative movement amount, and at least 1 of the acquired interference fringe image
A second calculation step of calculating a phase shift amount between one and another one from the phase of one cycle (2π) of the measured phase and the measured second relative movement amount. It is characterized by being provided.

According to the plane shape measuring method of the third aspect , the same effect as that of the plane shape measuring apparatus of the first aspect can be obtained.

A planar shape measuring method according to a fourth aspect is the planar shape measuring method according to the third aspect , wherein the measured first relative movement amount and the measured second relative amount. Transfer
Each momentum, a plurality of transfer which are respectively acquired at a plurality of observation positions on Watarushima that interference put on the obtained interference fringe image
Characterized in that it consists of the mean value of the rotation amount.

According to the plane shape measuring method of the fourth aspect , the same effect as that of the plane shape measuring apparatus of the second aspect can be obtained.

A storage medium according to a fifth aspect is a mechanically readable storage medium that stores a program for executing the planar shape measuring method, and the planar shape measuring method comprises:
A mechanically readable storage medium storing a program for executing a planar shape measuring method, wherein the planar shape measuring method comprises a first optical reflection image from an observation surface of an object to be measured and a reference surface. An interference step of causing the second optical reflection image to interfere with each other, a phase shift step of performing a phase shift of the optical phase of the interference fringe image generated by the interference by at least three phase shift amounts, and the at least three phase shifts calculating an interference fringe image acquiring step of acquiring at least three interference fringe images whose phase is shifted, the interference fringe image acquiring step by acquired the at least three interference Shimaga image or et shape of the observation surface in an amount A first measurement step for measuring the phase of one cycle (2π) of the phase from one of the acquired interference fringe images. And flop, at least a second measurement step of measuring a first relative movement amount between one another one of the acquired interference fringe image, at least, the obtained interference fringe image 1 A third measurement step of measuring a second relative movement amount between one and the other one;
At least one of the acquired interference fringe images and the other one
A first calculation step of calculating a phase shift amount between the bracts and a phase as a first relative movement amount the measured for one period of the measured phase (2 [pi), at least, is the acquisition The amount of phase shift between one of the interference fringe images and the other one is determined by one period (2
The second calculation step of calculating from the phase of π) and the measured second relative movement amount.

According to the storage device of claim 5 ,
The same effect as that of the planar shape measuring device described in 1 can be obtained.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a planar shape measuring apparatus according to a first embodiment of the present invention, which uses an optical path as a phase shift method.
It is a block diagram which shows schematic structure of the planar shape measuring device using a length variable system .

In FIG. 1, a planar shape measuring apparatus 10 according to the present embodiment mainly comprises a light source 11 composed of a red semiconductor laser, a beam splitter 12, and a reference mirror 1.
3, a reference mirror micro-displacement mechanism 14 that supports the reference mirror 13 and includes a piezo element, a displacement mechanism control device 15 connected to the displacement mechanism 14, and an imaging device 16.

The laser light emitted from the light source 11 enters the beam splitter 12 via the objective lens 17.
The light that has passed through the beam splitter 12 is collimated by the collimator lens 18 and illuminates the reference mirror 13. Part of the light is reflected on the surface of the reference mirror 13, and the light that has passed through the reference mirror 13 is , Is reflected by the surface to be measured (observation surface) of the object to be measured 19.

As a result, the light reflected by the surface of the reference mirror 13 and the light reflected by the surface to be measured of the object to be measured 19 are superimposed again by the reference mirror 13 to form interference light. Then, it is guided again downward in the figure by the beam splitter 12 via the collimator lens 18. This light is imaged on the light receiving surface of the imaging device 16 by the imaging lens 20.

The image pickup result of the image pickup device 16 is sent to the image processing device 22 provided in the control computer 21,
It can be visually observed by the monitor 23.

Further, the displacement mechanism control device 15 applies a desired voltage to the reference mirror micro displacement mechanism 14, and the reference mirror micro displacement mechanism 14 displaces the reference mirror 13 according to the voltage applied to the piezo element. By doing so, the phase shift is performed.

The plane shape measuring process by the plane shape measuring apparatus according to the first embodiment of the present invention having the above-mentioned structure will be described below.

The plane shape of the object to be measured is calculated by analyzing at least three pieces of interference fringe image information I _i (x, y) using a known plane shape analysis method.

The interference fringe image information is the light intensity of the interference fringes.
It can be represented by I (x, y). Specifically, x, y are x-y coordinates of the surface to be inspected, φ (x, y) is a phase, and δ _i is a phase shift amount. I _i (x, y) = I _B (x, y) + I _A (x, y) cos [φ (x, y) + δ _i ] ... (1) It changes sinusoidally with respect to the shift amount δ _i .

In the equation (1), δ ₁ =
0, δ ₂ = α, by substituting _{δ 3 = β, I 1 (} x, y) = I B (x, y) + I A (x, y) cos [φ (x, y)] I 2 ( x, y) = I _B (x, y) + I _A (x, y) cos [φ (x, y) + α] (2) I ₃ (x, y) = I _B (x, y) _{+ I A (x, y)} cos [φ (x, y) + β] is obtained. At this time, the phase φ (x, y) is

[0038]

[Equation 2]

It is represented by

FIG. 2 is a flowchart of the plane shape measuring process by the plane shape measuring apparatus according to the embodiment of the present invention.

In FIG. 2, first, an interference fringe image I ₁ is picked up at a phase of 0 ° (step S1), and the phase a for one cycle (2π) of the phase is measured (FIG. 3 (a)) (step S2). ).

Then, after performing a small amount of phase shift (step S3), the interference fringe image I ₂ is picked up (step S3).
4) The relative movement amount b between the interference fringe image I ₁ and the interference fringe image I ₂ is measured (FIG. 3B) (step S5). In this step, when the interference fringe image I ₁ and the interference fringe image I ₂ are not parallel to each other, the relative movement amount b is measured at a plurality of observation positions on the interference fringe, and an average value thereof is taken. Is preferred.

In the following step S6, the phase shift is made small.
Do the amount. After that, the interference fringe image I₃(Step S
7), interference fringe image I₁And interference fringe image I₃Relative movement amount to
c is measured (FIG. 3C) (step S8). Book
Interference fringe image I ₁And interference fringe image I₃And each other
If it is not parallel to the
Then, the relative movement amount c is measured, and the average value thereof is calculated.
Is preferred.

In step S9, the phase shift amount α is calculated by α = 2πb / a, and then step S
At 10, the phase shift amount β is calculated by β = 2πc / a, and these α value and β
Substituting the value into equation (2), the three interference fringe image information I ₁ (x,
y), I ₂ (x, y), and I ₃ (x, y) are calculated (step S11).

In step S12, the three pieces of interference fringe image information I ₁ (x, y), I ₂ (x, y), and I ₃ (x, y) are publicly known such as phase connection processing and phase-plane conversion processing. The plane shape is calculated by the plane shape analysis method.

According to the processing of FIG. 2, the phase a for one cycle (2π) of the phase is measured from the interference fringe image I ₁ at the phase 0 ° (step S2), and then the phase shift is performed by a small amount ( The relative movement amount b between the interference fringe image I ₁ and the interference fringe image I ₂ is measured based on the interference fringe image I ₂ at the time of step S3) (step S5), and the phase shift is further minutely performed (step S6). ) relative moving amount c of the interference fringe image I ₁ on the basis of the interference fringe image I ₃ and the interference fringe image I ₃ is measured at the time (step S8), and calculates the amount of phase shift alpha by α = 2πb / a (Step S9), then β = 2πc / a
Since the phase shift amount β is calculated by (step S10), the phase shift amount in the phase shift method can be acquired with high accuracy and the planar shape can be accurately measured without using dedicated hardware.

FIG. 4 is a block diagram showing a schematic configuration of a planar shape measuring apparatus according to the second embodiment of the present invention, which uses a wavelength variable system as a phase shift method.

This apparatus is replaced with the reference mirror micro-displacement mechanism 14 and the displacement mechanism controller 15 in the apparatus shown in FIG.
A wavelength variable light source 31 and a wavelength variable device 32 are provided, and the rest of the configuration is the same as the device of FIG.

In FIG. 4, a planar shape measuring apparatus 30 according to the present embodiment mainly includes a light source 31 composed of a wavelength tunable red semiconductor laser, a wavelength control device 32 connected to the light source 31, and a beam splitter 12. , Reference mirror 1
3 and the image pickup device 16.

In the apparatus of FIG. 4, similarly to the apparatus of FIG. 1, the light reflected on the surface of the reference mirror 13 and the DUT 1 are measured.
The light reflected by the test surface (observation surface) 9 is the reference mirror 1
The interference light formed by being superposed again by 3 is imaged on the light receiving surface of the imaging device 16 by the imaging lens 20, the imaging result by the imaging device 16 is sent to the image processing device 22, and is visually observed by the monitor 23. be able to.

In the apparatus shown in FIG. 4, the wavelength tunable controller 32 applies a desired voltage to the light source 31 to change the wavelength of the light source 31, thereby performing the phase shift.

Since the planar shape measuring process by the apparatus of FIG. 4 is executed in the same manner as the process of FIG. 2 in the first embodiment of the present invention described above, its explanation is omitted.

FIG. 5 is a block diagram showing a schematic configuration of a planar shape measuring apparatus according to a third embodiment of the present invention, which uses a trispectral method as a phase shift method.

In FIG. 5, the planar shape measuring apparatus 40 according to the present embodiment mainly comprises a light source 41 composed of a red semiconductor laser, a beam splitter 42, and a reference mirror 4.
3, a λ / 4 wave plate 44, a first spectroscopic optical system 45,
It comprises a second spectroscopic optical system 46 and a third spectroscopic optical system 47.

The first spectroscopic optical system 45 includes a non-polarizing beam splitter 45a, a λ / 4 wavelength plate 45b, and a polarizing plate 45.
c, an attenuation plate 45d, and an image pickup device 45e, the second spectroscopic optical system 46 includes a non-polarization beam splitter 46a.
, The non-polarizing beam splitter 46a, and the λ / 2 wave plate 4
6b, a polarizing plate 46c, an attenuating plate 46d, and the imaging device 4
The third spectroscopic optical system 47 includes a non-polarizing beam splitter 47a, a polarizing plate 47b, and an imaging device 47.
It consists of c and.

The laser light emitted from the light source 41 is incident on the beam splitter 42 via the objective lens 48.
The light transmitted through the beam splitter 42 is collimated by the collimator lens 49, illuminates the reference mirror 43, a part of the light is reflected on the surface of the reference mirror 43, and the light transmitted through the reference mirror 43 is , Λ / 4 wave plate 44
Is reflected by the surface of the object to be measured 19 via.

As a result, the light reflected by the surface of the reference mirror 43 and the light reflected by the surface to be measured of the object to be measured 19 and passing through the λ / 4 wave plate 44 are re-superposed by the reference mirror 43 and interfered with each other. To form. Then, it is guided again downward in the figure by the beam splitter 42 via the collimator lens 49. This light passes through the first spectroscopic optical system 45, the light receiving surface of the imaging device 45 e, the second spectroscopic optical system 46, the light receiving surface of the imaging device 46 e, and the third spectroscopic optical system 47, the imaging device. Images are formed on the light receiving surfaces of 47c.

The image pickup results of the image pickup devices 45e, 46e, 47c are sent to the image processing device 52 provided in the control computer 51, and can be visually observed by the monitor 53.

In the plane shape measuring process by the apparatus of FIG. 5, the interference fringe images I ₁ , I ₂ , and I ₃ which are mutually phase-shifted by the three-spectral phase shift method are simultaneously acquired, and then the steps S2 and S5 of FIG. , S8, the phase a and the relative movement amounts b and c are measured, and then steps S9 to S12 in FIG.
The process of is executed. In this case, the interference fringe images I ₁ , I ₂ , I
₃ may be acquired sequentially instead of simultaneously.

In the above embodiment, the planar shape measuring process using the phase shift method has been described. However, this process is programmed and written in a storage medium, and the program is read from the storage medium and executed by a known device. However, the above-described processing can be executed. The storage medium is a floppy (registered trademark) disk, hard disk, or CD-R.
Various types such as OM and MO are conceivable, but it is not limited to a specific type as long as the above program can be stored.

[0061]

[0062]

[0063]

As described in detail above, according to the plane shape measuring apparatus of the first aspect, at least three interference fringe images having different phase shift amounts are acquired, and one of the acquired interference fringe images is acquired. From one to one phase (2π), and at least one of the acquired interference fringe images and the other one.
A first relative movement amount between the bracts, at least, the second measures the relative amount of movement between one still another one of the acquired interference fringe image, at least, have been acquired interference The phase shift amount between one of the fringe images and the other one is calculated from the phase of one cycle (2π) of the measured phase and the first relative movement amount, and at least the acquired interference fringe image Of one of the measured phase and the second relative movement amount, the phase shift amount between one of the two and the other one is calculated without using dedicated hardware. It is possible to acquire the phase shift amount in the phase shift method with high accuracy and accurately measure the planar shape.

[0064] According to the planar shape measuring apparatus according to claim 2, wherein each of the first relative movement amount and the second relative movement amount is more on Watarushima interference that put the acquired interference fringe image The interference fringe images obtained are not parallel to each other because they consist of the average value of multiple movements obtained at each observation position.
Even in such a case, the predetermined phase shift amount can be acquired accurately.

According to the plane shape measuring method of the third aspect , the same effect as that of the plane shape measuring apparatus of the first aspect can be obtained.

According to the plane shape measuring method of the fourth aspect , the same effect as that of the plane shape measuring apparatus of the second aspect can be obtained.

According to the storage medium of claim 5 ,
The same effect as that of the planar shape measuring device described in 1 can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a schematic configuration of a planar shape measuring apparatus according to a first embodiment of the present invention, which uses a variable optical path length method as a phase shift method.

FIG. 2 is a flowchart of a plane shape measuring process by the plane shape measuring apparatus according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a relative movement amount of interference fringes, (a)
In the case of the interference fringe image I ₁ , (b) is the case of the interference fringe image I ₂ , and (c) is the case of the interference fringe image I ₃ .

FIG. 4 is a configuration diagram showing a schematic configuration of a planar shape measuring apparatus according to a second embodiment of the present invention, which uses a wavelength variable system as a phase shift method.

FIG. 5 is a configuration diagram showing a schematic configuration of a planar shape measuring apparatus according to an embodiment of the present invention, which uses a trispectral method as a phase shift method.

FIG. 6 is an explanatory diagram of a linear phase shift error.

[Explanation of symbols]

10, 30, 40 Plane shape measuring device 11,31 light source 12, 42 Beam splitter 13, 43 Reference mirror 14 Reference mirror micro displacement mechanism 15 Displacement mechanism controller 16 Imaging device 19 Object to be measured 21,51 control computer 22,52 Image processing device 32 wavelength control device 44 λ / 4 wave plate 45 First Spectroscopic Optical System 46 Second Spectroscopic Optical System 47 Third Spectroscopic Optical System

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-7-306006 (JP, A) JP-A-9-250907 (JP, A) JP-A-11-173808 (JP, A) JP-A 2000-275007 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01B 9/00-11/30 102

Claims (5)

(57) [Claims] 1. An interference optical system that causes a first optical reflection image from an observation surface of an object to be measured and a second optical reflection image from a reference surface to interfere with each other, and an interference fringe image generated by the interference. Phase shift means for performing phase shift of the optical phase by at least three phase shift amounts, interference fringe image acquisition means for obtaining at least three interference fringe images phase-shifted by the at least three phase shift amounts, and the interference in planar shape measuring apparatus comprising a calculation unit configured to calculated the at least three interference Shimaga image or <br/> et shape of the observation surface acquired by fringe image acquiring means, said calculation means has been the acquisition First measuring means for measuring the phase of one phase (2π) of the phase from one of the interference fringe images, and at least one of the acquired interference fringe images and the other one.
Second measuring means for measuring a first relative movement amount between the two and at least a second relative movement amount between one of the acquired interference fringe images and the other one. And a third measuring means for performing at least one of the acquired interference fringe images and the other one.
At least the first calculation means for calculating the amount of phase shift between the two from the phase for one cycle (2π) of the measured phase and the measured first relative movement amount. Calculating a phase shift amount between one of the interference fringe images and the other one from the phase of one cycle (2π) of the measured phase and the measured second relative movement amount. 2. A plane shape measuring apparatus comprising: two calculating means. 2. Each of the measured first relative movement amount and the measured second relative movement amount at a plurality of observation positions on an interference fringe in the acquired interference fringe image, respectively. The planar shape measuring apparatus according to claim 2, wherein the planar shape measuring apparatus comprises an average value of a plurality of acquired movement amounts. 3. An interference step of causing a first optical reflection image from an observation surface of an object to be measured and a second optical reflection image from a reference surface to interfere with each other, and an optics of an interference fringe image generated by the interference. Phase shift step of performing the phase shift of the target phase by at least three phase shift amounts, an interference fringe image acquisition step of acquiring at least three interference fringe images phase-shifted by the at least three phase shift amounts, and the interference fringes in planar shape measuring method and a calculation step of calculating the acquired said at least three interference Shimaga image or et shape of the observation surface by the image acquisition step, the calculating step, 1 of the acquired interference fringe image A first measurement step of measuring the phase of one cycle (2π) of the phase, and at least one of the acquired interference fringe images and the other one.
A second measurement step of measuring a first relative movement amount between the two and at least a second relative movement amount between one of the acquired interference fringe images and the other one. The third measurement step, and at least one of the acquired interference fringe images and another
A first calculation step of calculating a phase shift amount between the bracts and a phase as a first relative movement amount the measured for one period of the measured phase (2 [pi), at least, is the acquisition Calculating a phase shift amount between one of the interference fringe images and the other one from the phase of one cycle (2π) of the measured phase and the measured second relative movement amount. 2. A plane shape measuring method, comprising: 4. The measured first relative movement amount and the measured second relative movement amount are respectively measured at a plurality of observation positions on an interference fringe in the acquired interference fringe image. 4. The planar shape measuring method according to claim 3, comprising an average value of a plurality of acquired movement amounts. 5. A mechanically readable storage medium storing a program for executing a planar shape measuring method,
The plane shape measuring method is the first method from the observation surface of the measured object.
Interference step of causing the optical reflection image of the second optical reflection image from the second optical reflection image from the reference surface, and a phase shift of the optical phase of the interference fringe image generated by the interference with at least three phase shift amounts. A shift step and at least 3 phase-shifted by the at least 3 phase shift amounts.
Interference fringe image acquisition step of acquiring one interference fringe image,
And a calculation step of calculating the interference fringe image corresponding acquired by the acquiring step at least three interference Shimaga image or et shape of the observation surface, the calculating step, from one of the acquired interference fringe image A first measurement step of measuring a phase for one cycle (2π) of the phase, and at least one of the acquired interference fringe images and another one.
A second measurement step of measuring a first relative movement amount between the two and at least a second relative movement amount between one of the acquired interference fringe images and the other one. And a third measurement step for performing at least one of the acquired interference fringe images and the other one.
A first calculation step of calculating a phase shift amount between the bracts and a phase as a first relative movement amount the measured for one period of the measured phase (2 [pi), at least, is the acquisition Calculating a phase shift amount between one of the interference fringe images and the other one from the phase of one cycle (2π) of the measured phase and the measured second relative movement amount. 2. A storage medium comprising: two calculation steps.