JP2001296104A - Interference fringe detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate and detect interference fringes by automatically focusing an interference fringe detecting apparatus and adjusting the inclination of the apparatus. SOLUTION: The interference fringe detecting apparatus is provided with an interference fringe generating means, which generates interference fringes by branching the light emitted from a light source to the surface of an object to be measured and a reference surface and putting reflected light rays from the surfaces upon another and detects the interference fringes formed of the light having a first specific wavelength, an inclined angle measuring means which obtains information on the inclination of the surface of the object from the optical axis of an objective lens, by detecting a second specific wavelength component of the reflected light rays of the luminous flux projected upon the surface of the object, and a focal position measuring means which obtains the information on the deviation amount of the surface of the object from the focal point of the objective lens by detecting a third specific wavelength component of the patterned reflected light rays of the luminous flux projected upon the surface of object and transmitted through a pattern. The detecting device is also provided with a control means which calculates the inclination deviation amount of the surface from a prescribed angle or the position deviation amount of the surface from the focal point based on the detected information from the measuring means and issues a command that controls the attitude or position of the object.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an interference fringe detecting apparatus for measuring the surface shape of an object to be measured using interference fringes.

[0002]

2. Description of the Related Art As an apparatus for measuring the shape of a mirror-finished surface with high accuracy, for example, a magazine "Optical Technology Contact",
As described in Vol. 31, 1993, No. 12, pp. 713 to 719, a two-beam interference microscope is applied, and a surface shape is calculated from generated interference fringes by using a phase shift method or the like. Two-beam interference microscope
An interference microscope utilizing the light interference phenomenon, in which light emitted from a light source is split by a half mirror in two directions, that is, a surface of an object to be measured and a reference mirror, and light reflected from each is overlapped. Since the brightness is maximized in a portion where the distance to the surface is completely equal, and the brightness is minimized in a portion having a difference of λ / 2 (where λ is the wavelength of light), an interference fringe is generated. Is a microscope that enables observation with an eyepiece.

However, in order to generate interference fringes with an interference microscope, the distance between the surface of the object to be measured and the surface of the reference mirror must be adjusted (normally, the surface of the object to be measured is focused or focused to focus on the objective lens). Not only), but also the inclination must be adjusted with high accuracy. Objective lens magnification,
Depending on the bandwidth of the wavelength of the light source, for focusing, for example, when the magnification of the objective lens is 5 times, and when the light source uses light having a wavelength with a half width of 20 nm, a position adjustment of about 20 μm is necessary. is there. The adjustment of the inclination is, for example, 2 m
In order to make several interference fringes appear in the field of view of m, it is necessary to adjust the accuracy with an accuracy within 0.04 degrees.

In order to measure the surface shape of industrially produced parts, it is necessary to generate interference fringes quickly in order to achieve high productivity, and it is desired to automatically perform focusing and tilt adjustment. I have. As an automatic focusing method in an interference fringe microscope, for example, a magazine Appl.Opt., 31, No.
31 (1992) 6684-6689 (known example 1). This utilizes the fact that the luminance is maximized in the zero-order interference fringes, scans the interference objective lens in the depth of focus direction while measuring the amount of reflected light with a point detector,
The position at which the output value of the point detector becomes maximum is set as the focusing position. As a microscope autofocus system, a system in which an autofocus stripe pattern is arranged at a position of a field stop of a microscope, an image of the stripe pattern is formed on the surface of an object to be measured, and the image is detected by a line sensor is commercially available. (Chuo Seiki Co., Ltd .: Microscope autofocus system) (known example 2).

Further, the three-dimensional shape measuring device in Japanese Patent Publication No. 6-52168 irradiates condensed light toward the object,
A focusing discrimination optical system for discriminating a relative positional relationship between the condensing position of the condensed light and the object and an inclination angle measuring optical system for measuring an inclination angle of the object at the condensing position are shown (known in the art). Example 3). To determine the focusing state, light from the focusing light source is made incident on only the upper half of the objective lens, collected on the surface of the object to be measured, reflected from the object to be measured, and passed through the lower half of the objective lens. Is detected by a sensor provided behind the objective lens, and when the distance between the objective lens and the surface of the DUT changes, the reflection position of the condensed light changes and the optical path of the reflected light through the objective lens is changed. It takes advantage of the fact that it changes and the position that reaches the sensor changes. In the tilt angle measurement, the light from the tilt angle light source is made incident parallel to the optical axis of the objective lens.
The light condensed on the object to be measured on the optical axis, reflected from the object to be measured, and passed through the objective lens is detected by another sensor provided behind the objective lens to perform the measurement. This is based on the fact that if the surface is inclined, the direction of the reflected light changes and the position at which the light reaches the sensor changes.

[0006]

However, in the known example 1, it is not confirmed until the object to be measured or the objective lens is moved to the point where the focus is passed until the zero-order interference fringe is confirmed. It is necessary to move by more than the variation range of the surface position, and there is a problem that measurement of an object having large dimensional variation requires time. In addition, the narrower the bandwidth of the wavelength of the light source is, the smaller the change in the luminance of the interference fringes becomes. Therefore, there is a problem that the focusing cannot be performed with high accuracy when using light of a narrow band. Known example 2 has a problem in that when it is used for an interference microscope, it is not possible to distinguish between projection fringes for focusing and interference fringes generated on the surface. Known example 3 is a measuring device for measuring the distance and the inclination between the objective lens and the object, and does not have means for generating and detecting interference fringes. The present invention automatically performs focusing and tilt adjustment to generate and detect interference fringes even when an operation for generating interference fringes is required each time when the dimensions of the object to be measured vary and the measured fringes are measured. An object of the present invention is to provide an interference fringe detection device useful for measuring the shape of an object surface in a short time.

[0007]

An interference fringe detecting device according to the present invention divides light emitted from a light source into a surface of an object to be measured and a reference surface, and superimposes light reflected from each to generate interference fringes. Interference fringe generating means for detecting an interference fringe formed by light of a first specific wavelength, and detecting and measuring a second specific wavelength component of reflected light of a light beam applied to the surface of the object to be measured Tilt angle measuring means for obtaining information relating to the tilt between the object surface and the optical axis of the objective lens; and detecting a third specific wavelength component transmitted through the pattern from reflected light of the pattern projected on the surface of the object to be measured. A focus position measuring means for obtaining information relating to a shift amount from the focus of the objective lens, and a tilt shift amount from a predetermined angle and a focus shift amount based on detection information from the tilt angle measuring means and the focus position measuring means. A finger that calculates the displacement and controls the posture and position of the DUT It is characterized in that it has a control means for outputting. Further, in the interference fringe detecting device of the present invention, the interference fringe generating means includes: a sensor for detecting the interference fringe; a filter mounted on the front surface of the sensor and transmitting light of a first specific wavelength; A stage on which an object to be measured that can control the position and inclination of the surface in the direction of the optical axis and the direction perpendicular to the optical axis is mounted, the inclination angle measuring means includes a light beam irradiating means for inclination angle measurement, and a surface A sensor for detecting the reflected light position of the light beam for measuring the tilt angle applied to the sensor, and a filter mounted on the front surface of the sensor and transmitting a second specific wavelength different from the first specific wavelength. The focal position measuring means may be a third position different from the first and second specific wavelengths.
A sensor that detects light from the surface of the DUT onto which a pattern having a portion transmitting a specific wavelength is projected at a different position, and a filter mounted on the front surface of the sensor and transmitting a third specific wavelength. It is good to prepare.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of the interference fringe detection device according to the present invention. Interference fringe generating means 1 based on an interference microscope structure, tilt angle measuring means 2 for measuring the inclination between the surface of the object to be measured and the optical axis of the objective lens, and measurement of the amount of deviation of the surface of the object from the focus of the objective lens. Based on the measurement information from the focal position measuring means 3 and the inclination angle measuring means and the focusing position measuring means, the amount of inclination deviation from a predetermined angle and the amount of positional deviation from the focal point are calculated, and the posture and the posture of the object to be measured are calculated. Control means (not shown) for outputting a command for controlling the position is provided.

The interference fringe generating means 1 includes a lens barrel 5 in which main optical elements related to interference fringes are incorporated, and an illumination optical unit 6.
And a stage 7 for controlling the position and orientation of the device under test. The lens barrel unit 5 includes, in the first lens barrel 8, optical elements related to an interference objective lens system, an illumination optical system, a tilt angle measurement system, a focus measurement system, and an interference fringe measurement system, which will be described later. They are aligned and assembled in order from the bottom. The optical element of the interference objective lens system is an objective lens 18.
And a half prism 19 installed under the half prism 19, and a smooth surface provided at a side of the half prism 19 in a direction orthogonal to the optical axis of the objective lens 18, at an optical path length position equal to the focal length of the objective lens 18. A reference mirror 21 disposed;
For example, the bandpass filter 20 provided on the front surface of the reference mirror 21 and transmitting only light of a specific wavelength.

The optical element of the illumination optical system includes an objective lens 18
Is a half prism 17 aligned above. A second lens barrel 9 forming an outer shell of the illumination optical unit 6 is attached to the first lens barrel 8 on the side where the half prism 17 is disposed, and illumination light from the illumination optical unit 6 The light is reflected by the half prism 17 and irradiated toward the objective lens 18.

The illumination optical unit 6 includes a light source 10, a lens 11,
An aperture stop 12, a lens 13, a parallel plate 14 having a pattern formed by stripes transmitting only a specific wavelength, a field stop 15, and a projection lens 16 are arranged and arranged in the second lens barrel 9 in this order. Is sequentially passed through the optical element and reaches the half prism 17.

As an optical element for measuring a tilt angle, a half prism 32 is provided on the upper part of the half prism 17 of the lens barrel 5 so as to be aligned. Half prism 32
The tilt angle measuring means 2 is attached to the first lens barrel 8 on the side where is disposed, and the light from the light source of the tilt angle measuring means 2 is reflected by the half prism 32 and the objective lens 1
Irradiated toward 8.

The inclination angle measuring means 2 includes a half prism 32
A half prism 31 arranged on the outer shell provided on the side surface of the half prism 32 so that the reflection surface is parallel to the reflection surface of the half prism 32
And a band-pass filter 3 that transmits only light of a specific wavelength
3 and a two-dimensional sensor 34 are provided in order in a straight line, and the light source 30 is provided above the reflection surface of the half prism 31. As the light source 30, for example, a light source such as a laser that emits light (hereinafter, referred to as a light beam) having a high directivity and traveling straight in a light beam shape is used. Light source 30 and half prism 31
Are arranged so that the center of the light beam reflected by the half prism 32 coincides with the optical axis of the objective lens 18.

Above the half prism 32 of the lens barrel 5,
An imaging lens 45 and a half prism 44 as a focusing measurement system optical element are provided in order aligned. The focus position measuring means 3 is attached to the first lens barrel 8 on the side where the half prism 44 is arranged,
The light transmitted through the imaging lens 45 is reflected by the half prism 44 and is emitted toward the detection sensor of the focus position measuring unit 3.

The focus position measuring means 3 includes a half prism 4
And a half prism 42 disposed adjacent to the side surface of the half prism 44 such that the reflection surface is parallel to the reflection surface of the half prism 44.
A front pin detection sensor 41 provided above the reflection surface of the half prism 42, a rear pin detection sensor 40 provided on the transmitted light side of the half prism 42, and a specific pin provided between the half prism 44 and the half prism 42. A sharp cut filter 43 that transmits only light having a wavelength or more is provided. The front-pin detection sensor 41 and the rear-pin detection sensor 40 are arranged near a light path length position equal to the focal length of the imaging lens 45 so as to be a predetermined position described later.

Above the half prism 44 of the lens barrel 5,
As an optical element related to the interference fringe measurement system, a band-pass filter 51 that transmits only light of a specific wavelength and a two-dimensional sensor 50 are provided in alignment with each other. The two-dimensional sensor 50 is disposed so that the detection surface is orthogonal to the optical axis and at the focal position of the imaging lens 45. Information on the interference fringes from the two-dimensional sensor 50 is sent to a surface shape measuring unit (not shown), and the surface shape can be measured by a phase shift method or the like.

An object 60 to be measured is located below the lens barrel 5.
Is mounted on the stage 7. Stage 7
Has moving means having a known structure capable of controlling the position of the objective lens 18 along the optical axis direction, and moving means having a known structure capable of two-dimensionally controlling the inclination of a plane orthogonal to the optical axis. ing. Each moving means is electrically connected to a control means to which information from the inclination angle measuring means 2 and the in-focus position measuring means 3 is inputted, and controls the position and the inclination of the stage 7 by a command from the controlling means. can do.

The lens barrel 5 and the illumination optical unit 6 have an infinity corrected microscope structure. That is, in the lens barrel 5, the reflected light from the measured object 60 does not form an image with the objective lens 18, enters the imaging lens 45 as a parallel light beam at infinity, and forms an image with the imaging lens 45. In the illumination optical unit 6, light emitted from the light source 10 is transmitted through the lens 11 and collected, the degree of convergence of the light is controlled by the aperture stop 12, and transmitted through the lens 13 to become substantially parallel light. The state of the luminous flux is controlled, and the light passing through the field stop 15 and passing through the lens 16 becomes parallel light. Therefore, the light reflected by the half prism 17 enters the objective lens 18 as parallel light.

Thus, the stripe pattern of the parallel plate 14 is
The light enters the objective lens 18 as a parallel light beam at infinity by the lens 16, and is imaged at the focal position by the objective lens 18. In the infinity-corrected microscope, the in-focus state is established when the surface of the measured object 60 is at the focal position of the objective lens 18. When in the focused state, the light is divided by the half prism 19 and is directed to the reference mirror 21 and the object 60 to be measured.
The light reflected and returned interferes with each other, and has a stripe pattern (hereinafter, referred to as interference fringes) corresponding to the unevenness of the surface of the measured object 60.
To form

In this embodiment, the parallel flat plate 14 is 70
Light having a wavelength of 0 nm or more (hereinafter, referred to as focus determination wavelength light)
A stripe pattern was formed with a film that transmits only the light. Based on this, each filter had the following specifications. The band-pass filter 20 disposed in front of the reference mirror 21 has a specific wavelength equal to or less than the wavelength of the focus determination wavelength light, for example, 500 nm.
(Hereinafter referred to as interference wavelength light). The band-pass filter 33 of the tilt angle measuring means 2 transmits only light having a wavelength equal to or less than the wavelength of the focus determination wavelength light and different from the interference wavelength light, for example, a wavelength of 600 nm (hereinafter referred to as tilt angle wavelength light). Let it. The sharp cut filter 43 of the focus position measuring means 3 outputs the focus determination wavelength light (700
nm or more). The band-pass filter 51 disposed on the front of the two-dimensional sensor 50 transmits the interference wavelength light (500
nm).

Next, a method of measuring the tilt angle in the tilt angle measuring means 2 will be described. A light beam A having a high directivity emitted from the light source 30 is reflected by the half prism 31 at 90 degrees, enters the lens barrel 5, is reflected by the half prism 32, and is parallel with the optical axis of the lens barrel 5 as a center. Objective lens 1 as light flux
8, a spot having a center on the optical axis is formed on the surface of the measured object 60. The light flux B reflected from the spot passes through the half prism 19 and the objective lens 18, is reflected by the half prism 32, returns from the lens barrel 5 to the tilt angle measuring means 2, and passes through the bandpass filter 33. And reaches the two-dimensional sensor 34. Although the light transmitted through the half prism 31 includes the interference wavelength light (500 nm) reflected from the reference mirror 21, the band-pass filter 33 transmits only the tilt angle wavelength light (600 nm). The light reaching 34 is only light reflected from the surface of the device under test 60.

FIG. 2 shows the relationship between the inclination of the surface of the object 60 to be measured and the position of the light beam reaching the two-dimensional sensor 34, for the sake of simplicity, in the case where the inclination is in the horizontal direction on the paper. Was. Assuming that the surface of the device under test 60 is inclined by an angle α with respect to a plane orthogonal to the optical axis, the reflected light beam B from the spot enters the objective lens 18 at an angle 2α with respect to the optical axis. Since the spot at this time is at the focal position of the objective lens, the light beam incident on the objective lens 18 travels in parallel with the optical axis, and the center of the light beam is separated from the optical axis by H obtained by the following equation. . H = F × tan (2α) (F is known by the focal length of the objective lens 18)

The reflected light beam B reflected by the half prism 32 reaches the two-dimensional sensor 34 by being shifted from the incident light beam A by H. The reflected light flux B when the device under test 60 is not tilted is
The light path coincides with the incident light flux A, and the reflected light flux B at this time
The position on the two-dimensional sensor 34 can be detected in advance. If the position detected in advance is used as a reference, H can be obtained from the detected value of the reflected light beam B by the two-dimensional sensor 34, so that the inclination angle can be calculated by the above-described equation.

Next, a method of measuring the focus position will be described. A stripe pattern is formed on the parallel plate 14 of the illumination optical unit 6 with a film that transmits only the focus discrimination wavelength light (wavelength of 700 nm or more), and light of all wavelengths passes through the portion without the film. Light emitted from the light source 10 and transmitted through the parallel flat plate 14 is converted into a parallel light flux at infinity by the lens 16, reflected by the half prism 17, and imaged on the surface of the measured object 60 by the objective lens 18. By observing this image with light having a wavelength for determining focus, a stripe pattern of the parallel flat plate 14 (hereinafter, referred to as a projection stripe) can be seen on the surface of the measured object 60. This projection fringe is again converted into a parallel light beam by the objective lens 18, narrowed down by the image forming lens 45, passes through the half prism 44, the sharp cut filter 43, and the half prism 42, and is applied to the front focus detection sensor 41 and the rear focus detection sensor 40. Form an image. Sharp cut filter 43
Is a filter that transmits only the focus determination wavelength light,
Since the interference wavelength light (500 nm) is cut, only projection fringes appear on the front-pin detection sensor 41 and the rear-pin detection sensor 40, and no interference fringes appear.

As shown in FIG. 3, the front focus detection sensor 41
Is a sensor fixed so that a projection fringe forms an image on the sensor surface when the surface of the device under test 60 is located at a position closer to the focal position of the objective lens 18. Rear pin detection sensor 40
Is a sensor fixed such that projection fringes form an image on the sensor surface when the surface of the device under test 60 is located at a position farther than the focal position of the objective lens 18. That is, when the surface of the device under test 60 is exactly at the focal position of the objective lens 18 (the position B in the figure), the projection fringe is located at a position before the sensor surface on the front focus detection sensor 41 side (see FIG. An image is formed at the position (b 'in FIG. 2), and on the side of the rear focus detection sensor 40, an image is formed behind the sensor surface (the position of "b" in the drawing). When it is located at a predetermined position closer to the focal position (position A in the figure), the projection stripe forms an image on the sensor surface (position A 'in the figure) on the front focus detection sensor 41 side, and On the pin detection sensor 40 side, an image is formed behind the sensor surface (position "a" in the figure), and the surface of the measured object 60 is located at a predetermined position farther than the focal position of the objective lens 18 (c in the figure). Is located at a position before the sensor surface on the front focus detection sensor 41 side (see FIG. , At the position) of the C ', rear focus detection sensor 40
On the side, an image is formed on the sensor surface (the position indicated by C in the figure).

FIG. 4 shows the relationship between the difference in the image formation position of the projection fringes and the sensor output. As for the output waveform of the sensor, an image with the highest contrast is obtained when the projection fringes are formed on the sensor surface, and the contrast decreases as the projection fringes move away from the sensor surface. The output waveform of the front focus detection sensor is shown in FIG.
As shown in (a), the contrast of the waveform is the highest at the position A where the projection stripe exists on the sensor surface, and the contrast decreases as the projection stripe moves away from the sensor surface from B to C. Conversely, the output waveform of the rear focus detection sensor is shown in FIG.
As shown in (b), the contrast is highest in the case of C and the lowest in the case of A.

FIG. 5 shows a contrast value calculated by C = Σ | i−I | (where i is the luminance value of the projection fringes and I is the average value) of the front pin detection sensor and the rear pin detection sensor. When,
The relationship with the focal direction (Z direction) position of the measured surface is shown. FIG. 5A shows a front focus detection sensor contrast value characteristic curve 41 a and a rear focus detection sensor contrast value characteristic curve 4.
0a. When the surface of the device under test 60 is at the in-focus position b, the positions of the two sensors are adjusted in advance so that the contrast value of the front focus detection sensor and the contrast value of the rear focus detection sensor match. When the difference is calculated, as shown in FIG. 5 (b), a characteristic curve in which the contrast value is centered around the zero value can be obtained. Therefore, by calculating the contrast value from each of the front focus detection sensor 41 and the rear focus detection sensor 40 and calculating the difference, it is possible to calculate how far the surface of the measured object is away from the in-focus position. .

Next, the measurement of interference fringes will be described. The amount of inclination deviation from the reference and the amount of deviation from the focus are calculated by the control unit based on the detection information from the inclination angle measurement unit 2 and the focus position measurement unit 3. When the shift amount is calculated, a stage control amount that eliminates the shift amount is calculated, sent to the stage position / posture control means, and the stage position / posture is controlled. Thus, the surface of the DUT 60 mounted on the stage is corrected so as to be at the focal position of the objective lens 18 and perpendicular to the optical axis.

The light reflected from the DUT 60 and the reference mirror 21 by the light emitted from the light source 10 and the light source 30 causes an interference phenomenon to form an interference fringe. Is the interference wavelength light (500n
Since the bandpass filter 20 that transmits only m) is arranged, the interference fringes are formed only of the interference wavelength light. The light transmitted through the objective lens 18 and the imaging lens 45 forms an image on the two-dimensional sensor 50. However, other light is transmitted by the band-pass filter 51 provided on the way to transmit only the light of the interference wavelength light. The tilt angle wavelength light and the focus determination wavelength light are cut off, and only the interference fringes are imaged on the two-dimensional sensor 50. The interference fringes can be converted into a distance image by, for example, a phase shift method, and the surface shape can be measured.

As the two-dimensional sensor 34 of the inclination angle measuring means 2 and the two-dimensional sensor 50 of the interference fringe generating means 1, it is preferable to use a two-dimensional camera or a position sensor. The front-pin detection sensor 41 and the rear-pin detection sensor 40 of the focus position measuring means 3 may be two-dimensional sensors such as the two-dimensional camera and the position sensor.
When the pattern to be formed is a parallel stripe pattern, a one-dimensional line sensor may be used.

The greatest feature of the present invention is that the apparatus is a combination of a focus position measuring means, a tilt angle measuring means, an interference fringe generating means, and a control device electrically connected thereto. Of course, it is needless to say that the present invention is not limited to the configuration example described in the embodiment. For example, since the operations of the focus position measuring means, the tilt angle measuring means, and the interference fringe generating means do not need to be performed simultaneously, the tilt angle measuring means 2 and the illumination optical means 6 are alternately moved with respect to the lens barrel 5. It is also possible to adopt a configuration in which it is mounted so as to be movable and one of the half prisms 17 and 32 is unnecessary.

[0032]

As described above, the present invention has the following effects. 1) Since interference fringes can be generated when focusing and tilt adjustment are performed, the surface shape can be measured quickly. 2) Since the focusing and the tilt adjustment can be automatically performed, interference fringes can be efficiently generated even for an object to be measured having a large dimensional variation. 3) Since it is a method for preventing erroneous determination using lights of different wavelengths for focusing determination, tilt angle measurement, and interference fringe generation,
Optical elements could be shared, and a compact device could be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an interference fringe detection device of the present invention.

FIG. 2 is a diagram for explaining a tilt angle measuring method.

FIG. 3 is a diagram for explaining a focusing position measuring method;

FIG. 4 is a diagram showing a difference in output of a focus position detection sensor depending on an image formation position of a projection fringe.

FIG. 5 is a diagram showing a difference in contrast value between a front focus detection sensor and a rear focus detection sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Interference fringe generation means, 2 ... Inclination angle measurement means, 3 ... In-focus position measurement means, 5 ... Barrel part, 6 ... Illumination optical part, 7
... stage, 8 ... first lens barrel, 9 ... second lens barrel, 1
0, 30 ... light source, 14 ... parallel plate with pattern,
Reference numeral 16: Projection lens, 18: Objective lens, 21: Reference mirror, 45: Imaging lens, 60: Object to be measured, 17,
19, 31, 32, 42, 44: half prism, 2
0, 33, 51 ... band pass filter, 43 sharp cut filter, 34, 50 ... two-dimensional sensor, 40 ...
Rear pin detection sensor, 41 ... front pin detection sensor,

Continued on the front page F-term (reference) 2F064 AA09 CC04 FF00 GG12 GG13 GG22 GG42 GG58 HH03 JJ01 KK04 2F065 AA54 BB02 DD03 DD09 FF51 FF65 FF67 GG01 HH04 HH13 JJ03 JJ09 JJ26 LL00 QA12Q12 LL12 LL12 BA72 CB05 CB13 CB22 CC03 CC14 EB20 2H052 AA04 AD09 AF04

Claims (2)

[Claims] A light emitted from a light source is split into a surface of an object to be measured and a reference surface, and light reflected from each is superimposed to generate an interference fringe, and an interference formed by light of a first specific wavelength is generated. Interference fringe generating means for detecting fringes; information relating to the inclination between the surface of the object to be measured and the optical axis of the objective lens by detecting a second specific wavelength component of the reflected light of the light beam irradiated on the surface of the object to be measured And a third specific wavelength component transmitted through the pattern from among the reflected light of the pattern projected on the surface of the object to be obtained to obtain information relating to the amount of deviation from the objective lens focal point. Based on the focus position measurement means and the detection information from the tilt angle measurement means and the focus position measurement means, calculate the amount of tilt deviation from a predetermined angle and the amount of position deviation from the focal point, Control means for outputting a command for controlling the position. Fringe detection apparatus according to claim. 2. The interference fringe detecting device, wherein the interference fringe generating means includes a sensor for detecting the interference fringe, a filter mounted on a front surface of the sensor and transmitting light of a first specific wavelength, and an object to be measured. A stage for mounting an object to be measured, the surface of which can control the position and inclination of the surface in the direction of the optical axis and the direction perpendicular to the optical axis; the inclination angle measuring means; A sensor for detecting the reflected light position of the light beam for measuring the tilt angle applied to the sensor, and a filter mounted on the front surface of the sensor and transmitting a second specific wavelength different from the first specific wavelength. A focus position measuring means for detecting, at different positions, light from the surface of the DUT onto which a pattern having a portion transmitting a third specific wavelength different from the first and second specific wavelengths is projected; , A third identification attached to the front of this sensor 2. The interference fringe detecting device according to claim 1, further comprising: a filter that transmits the wavelength.