JPH10176906A - Measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the observation image and the inclination angle of a measuring target quickly and efficiently with a simple configuration. SOLUTION: The measuring device has a lighting unit 30 that can emit observation light for observing a measuring point 28a of a measuring target 28 and measuring light for measuring the inclination angle of the measuring target (measuring point) simultaneously, an image-forming unit 32 for forming measuring image light from the measuring target (measuring point) where observation image light and measuring light from the measuring target (measuring point) where the observation light is cast on a specific image-forming position, and a measuring unit 34 for simultaneously measuring the observation image and the inclination angle of the measuring target (measuring point) based on the observation image light and the measuring image light formed at the image- forming position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device used for inspecting an object to be measured such as a semiconductor component or an optical component.

[0002]

2. Description of the Related Art Conventionally, as this type of measuring device, for example, a measuring microscope device (hereinafter referred to as a prior art) disclosed in Japanese Patent Application Laid-Open No. 8-61914 is known. FIG.
As shown in FIG. 1A, in this conventional technique, the image light from the measuring object 2 is transmitted to the microscope main body 6 by the objective lens 4.
After being taken into the camera, the light is guided to the imaging device 12 and the eyepiece 14 via the imaging lens 8 and the prism 10. At this time, the stage 16 or the microscope main body 6 is relatively moved, and the measurement location 2a of the measurement target 2 (see FIG. 2B).
Is positioned within the observation field of view (focal position) of the objective lens 4, it is possible to visually observe the measurement location 2 a via the eyepiece 8, and at the same time, the measurement location 2 a is displayed on the monitor 18 by the image pickup device 12. Is displayed.

[0003]

However, in the above-mentioned prior art, any three points P specified on the surface of the object 2 are measured.
The inclination angle of the measurement point 2a is measured based on the positional relationship between P1, P2, and P3 (see FIG. 7B) (three-point measurement method).

[0004] However, this three-point measuring method takes a long measuring time, so that it is difficult to improve the measuring efficiency and has the following problems. That is, as shown in FIG. 7 (b), even if an inclined portion such as unevenness is present on the surface of the measurement object 2, the three points P1, P2, and P3 specified at the measurement point 2a.
Are positioned on the same plane H, the measurement object 2 is determined based on the positional relationship between these three points P1, P2, and P3.
There is a problem that (or the measurement point 2a) is determined to have a flat shape without an inclined portion.

On the other hand, for example, Japanese Patent Application Laid-Open No. 6-281408 discloses a measuring method using an autocollimator so that the actual inclination angle of the object 2 (or the measuring point 2a) can be measured. An apparatus is disclosed (FIG. 7).
(C)).

As shown in FIG. 7C, in an autocollimator, light from a light source 20 is disposed at a focal position of an objective lens 22 and has a crosshair 24a (see FIG. 7D).
Is transmitted through the focusing plate 24 engraved with the half mirror 26.
Is irradiated. The light reflected from the half mirror 26 is converted into parallel light by the objective lens 22 and applied to the measurement location 2 a of the measurement target 2. It is assumed that the surface of the measurement point 2a is polished flat. Measurement point 2
The reflected light reflected from a forms an image at a position S conjugate with the reticle 24 via the objective lens 22 and the half mirror 26. At this time, since the cross line 24a of the focusing screen 24 is formed at the conjugate position S, the measurement object 2 (or the target object 2 (or the target object 2) is detected by detecting the movement amount of the cross line image with respect to a reference point (not shown). , The inclination angle of the measuring point 2a) can be measured.

However, since the autocollimator has only a function of detecting the tilt angle, there is a problem that an observation image of the measurement object 2 (or the measurement location 2a) cannot be obtained.

An object of the present invention is to solve such a problem, and an object of the present invention is to measure an observation image and an inclination angle of a measurement object in a short time and efficiently with a simple configuration. It is to provide a possible measuring device.

[0009]

In order to achieve the above object, a measuring apparatus according to the present invention comprises an observation light for observing an object to be measured and a measurement for measuring an inclination angle of the object to be measured. A lighting unit capable of simultaneously emitting light, and a measurement image light from the measurement target irradiated with the observation light and the measurement light irradiated from the measurement target irradiated with the observation light at a predetermined imaging position. Based on the imaging unit to form an image, the observation image light and the measurement image light formed at the image formation position,
A measurement unit capable of measuring an observation image and an inclination angle of the measurement object.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a measuring device according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the measuring apparatus according to the present embodiment measures an observation light for observing a measurement location 28 a of the measurement target 28 and an inclination angle of the measurement target 28 (the measurement location 28 a). Unit 30 capable of simultaneously emitting measurement light for measurement, and measurement object 28 irradiated with observation light
An imaging unit 32 for imaging the observation image light from the (measurement location 28a) and the measurement image light from the measurement object 28 (measurement location 28a) irradiated with the measurement light at a predetermined imaging location; Based on the observation image light and the measurement image light formed on the
A measurement unit 34 is provided which can simultaneously measure an observation image and an inclination angle of the measurement object 28 (measurement point 28a).

The illumination unit 30 includes a measuring object 28 disposed at a focal position of a collimator lens 44 described later.
An observation light source 36 (for example, a halogen lamp) that emits observation light for observing the (measurement point 28a) and a measurement light source that emits measurement light for measuring an inclination angle of the measurement object 28 (the measurement point 28a). 38 (for example, a point light source such as an infrared laser) and a wavelength filter 40 capable of simultaneously emitting observation light and measurement light.

In this embodiment, as an example, a case where a halogen lamp is used as the observation light source 36 and an infrared laser is used as the measurement light source 38 will be described. In this case, the observation light becomes visible light and the measurement light becomes infrared light. As the wavelength filter 40, a dichroic mirror that transmits visible light in a specific wavelength band and reflects infrared light (hereinafter, referred to as a dichroic mirror 40 for illumination) is used.

The measuring device includes a half mirror 42 for reflecting observation light and measurement light emitted simultaneously from the illumination unit 30, and observation light (visible light) and measurement light (infrared light) reflected from the half mirror 42. ) Is measured object 2 at the same time
Collimator lens 44 for irradiating the measurement point 28a of No. 8
Are provided. In this case, the observation light and the measurement light simultaneously emitted from the illumination unit 30 are
Then, the light is converted into a parallel light beam via the collimator lens 44 and is emitted to the measurement location 28a. At this time, the observation light and the measurement light reflected from the measurement location 28a are collected in the imaging unit 32 via the collimator lens 44 and the half mirror 42.

The imaging unit 32 has an observation light (visible light)
A separation optical system for separating the measurement light (infrared light) from the measurement light, an observation light imaging optical system for forming the observation light at the image formation position I of the measurement unit 34, and a measurement light at the image formation position I. An imaging optical system for measuring light to be imaged, and a coupling optical system for coupling observation light and measurement light guided through the imaging optical systems for observation light and measurement light are provided.

The separation optical system includes a dichroic mirror 46 that transmits observation light and reflects measurement light (hereinafter, referred to as separation dichroic mirror 46). The observation light imaging optical system is used for observation light that defines the measurement object 28 (measurement point 28 a) and the imaging position I of the measurement unit 34 in an optically conjugate positional relationship by combining with the collimator lens 44. An imaging lens 48 is provided.

The measuring light imaging optical system, when combined with the collimator lens 44, defines the measuring light source 38 (infrared laser) and the image forming position I of the measuring unit 34 in an optically conjugate positional relationship. Imaging lens 50 for measuring light
And a pair of total reflection mirrors 5 for guiding the measurement light separated by the separation dichroic mirror 46 to the coupling optical system.
2 and 54.

The coupling optical system includes a dichroic mirror 56 that transmits observation light and reflects measurement light (hereinafter, coupling dichroic mirror 56). An imaging device 58 (for example, a CCD camera) having a light receiving element 58a positioned at the image forming position I is provided in the measurement unit 34.
And a monitor 60 for displaying an observation image of the measurement object 28 (measurement point 28 a) based on the image signal output from the image pickup device 58, and performing predetermined arithmetic processing on the image signal from the image pickup device 58. , Measurement object 28 (measurement point 28a)
And an angle calculator 62 for calculating the inclination angle of the vehicle. The light receiving element 58a is controlled so as to output an electric signal (image signal) having a value corresponding to the amount of received light.

The measuring object 28 is set on a stage 64 that can move in XYZ directions orthogonal to each other. The illumination dichroic mirror 40, the separation dichroic mirror 46, and the coupling dichroic mirror 56 all have the same optical characteristics.

Next, the operation of this embodiment will be described with reference to FIG.
This will be described with reference to FIG. FIG. 1 shows an image measurement operation using observation light (visible light), and FIG. 2 shows an inclination angle measurement operation using measurement light (infrared light). In addition, during the measurement operation, the observation light and the measurement light always travel in the optical path at the same time, but in the following description, the image measurement operation and the tilt angle measurement operation will be described with reference to different drawings.

As shown in FIG. 1, as the observation light (visible light) emitted from the observation light source (halogen lamp) 36 at a spread angle θ, only visible light in a specific wavelength band is selected by the dichroic mirror 40 for illumination. Later, lighting unit 3
Emitted from 0.

The observation light (visible light) emitted from the illumination unit 30 is applied to a measurement location 28a of the measurement object 28 via a half mirror 42 and a collimator lens 44. At this time, the measurement object 28 (measurement point 28
a) Specularly reflected light and scattered light (diffraction light) are generated from each point above. In the image measurement operation, description will be added focusing on scattered light (diffraction light).

The scattered light (diffracted light) generated from each point on the measurement object 28 (measurement point 28a) is captured by the collimator lens 44, and then becomes parallel light and passes through the half mirror 42 to be coupled. The light is guided into the image unit 32.

The scattered light (diffracted light) guided to the imaging unit 32 passes through the dichroic mirror 46 for separation, and then passes through the imaging lens 48 for observation light and the dichroic mirror 56 for coupling, and passes through the imaging device 58. Is formed on the light receiving element 58a.

At this time, an image signal corresponding to the amount of light received by the light receiving element 58a is output from the imaging device 58 to the monitor 60, and an observation image of the measurement object 28 (measurement point 28a) is displayed on the monitor 60. Will be.

As shown in FIG. 2A, measurement light (infrared light) emitted from a measurement light source (infrared light laser) 38 at a spread angle θ ′ is reflected from a dichroic mirror 40 for illumination. The light is emitted from the lighting unit 30. Note that the spread angle θ ′ of the measurement light is much smaller than the spread angle θ of the observation light (see FIG. 1).

The measurement light (infrared light) emitted from the illumination unit 30 is applied to the measurement location 28a of the measurement object 28 via the half mirror 42 and the collimator lens 44. At this time, the measurement object 28 (measurement point 28
a) Specularly reflected light and scattered light (diffraction light) are generated from each point above. In the tilt angle measuring operation, description will be given focusing on specularly reflected light.

The specularly reflected light generated from the measurement object 28 (measurement point 28a) is taken into the collimator lens 44, becomes convergent light, passes through the half mirror 42, and is guided into the image forming unit 32. Is done.

The specularly reflected light guided to the image forming unit 32 is reflected from the separating dichroic mirror 46,
A beam waist is formed at the focal position T of the collimator lens 44. Subsequently, the specularly reflected light is a total reflection mirror 52,
After being guided through the measuring light imaging lens 50 and the total reflection mirror 54, the light is reflected from the coupling dichroic mirror 56 and is imaged on the light receiving element 58 a of the imaging device 58. In this state, a spot of infrared light is formed on the light receiving element 58a.

At this time, an image signal corresponding to the amount of light received by the light receiving element 58a is output from the image pickup device 58 to the monitor 60, and a spot image of infrared light is displayed on the monitor 60. During the actual measurement operation, an observation image and a spot image of the measurement object 28 (measurement point 28a) are simultaneously displayed on the monitor 60.

An image signal from the image pickup device 58 is input to an angle calculator 62, where a predetermined calculation is performed. The angle calculator 62 calculates the tilt angle of the measurement target 28 (measurement point 28a) based on the image signal from the imaging device 58.

Next, a method of calculating the inclination angle will be described with reference to FIG.
This will be described with reference to FIG. First, the inclination angle of the measurement object 28 (measurement point 28a) is ω, ω = 0 (measurement object 2
8 (the state where the measurement point 28a is not inclined at all), the spot coordinates on the light receiving element 58a are (X0, Y
0), ω = α (a state in which the measurement object 28 (measurement point 28a) is inclined by the predetermined angle α), and the spot coordinates on the light receiving element 58a are (Xα, Yα).

The distance δ between the two coordinates is δ = {(Xα−X0) ² + (Yα−Y0) ² } ^1/2 .

When the focal length of the collimator lens 44 is f and the magnification of the measuring light imaging lens 50 is M, the reflection angle of the reflected light is 2ω with respect to the inclination angle ω. As a result, the inclination angle ω can be derived from the relational expression of ω = δ / 2Mf.

Further, the inclination direction β of the inclination angle ω can be derived from a relational expression of β = tan ⁻¹ {(Yα−Y0) / (Xα−X0)}.

As described above, according to the measuring apparatus of the present embodiment, it is possible to provide a measuring apparatus capable of simultaneously and efficiently measuring an observation image and an inclination angle of a measuring object with a simple configuration. Becomes Further, since the spot diameter of the infrared light can be extremely small, the measurement object 28
It is possible to locally measure the inclination angle of the (measurement point 28a). In this case, the measurement light source (infrared laser) 3
By arranging a light amount restricting means such as a diaphragm immediately before 8, for example, it is possible to improve measurement accuracy.

Next, a measuring apparatus according to a second embodiment of the present invention will be described with reference to FIGS. In the description of the present embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIGS. 3 and 4, the illumination unit 30 applied to the present embodiment has a light source 66 (for example, a light source 66 that emits randomly polarized light disposed at the front focal position of the collimator lens 44). (Halogen lamp), a polarizer 68 that transmits only light of a predetermined linear polarization component, and a λ / 2 plate 70 having a small opening 70a formed at the center.

The polarizer 68 is configured to transmit only light having a linearly polarized light component in a direction perpendicular to the plane of the drawing of the drawing, out of random polarized light. The λ / 2 plate 70 has a crystal axis (not shown) of 45 ° with respect to the polarization direction of the polarizer 68.
It is positioned so as to be inclined.

In such an illumination unit 30, the light having a random polarization component emitted from the light source 66 at the spread angle θ is formed into a light having a linear polarization component in the vertical direction by the polarizer 68. Irradiation is performed on the λ / 2 plate 70 having 70a.

At this time, the light transmitted through the portion other than the minute aperture 70a, that is, the light transmitted through the λ / 2 plate 70 is converted into a light having a linearly polarized light component in a direction parallel to the paper of FIG. (See FIG. 3). On the other hand, the light that has passed through the small aperture 70a is not affected by the action of the λ / 2 plate 70, so that linearly polarized light perpendicular to the plane of the drawing is maintained (see FIG. 4).

In the present embodiment, of the light emitted from the illumination unit 30 through the λ / 2 plate 70, the minute aperture 7
0a is used as light for measuring the tilt angle (measurement light), while a portion other than the minute aperture 70a, that is, the λ / 2 plate 70
Is used as light for image measurement (observation light).
In this case, the divergence angle θ ′ of the measurement light is much smaller than the divergence angle (θ−θ ′) of the observation light.

The separation optical system applied to the present embodiment transmits observation light having a linear polarization component in a direction parallel to the plane of the drawing and transmits measurement light having a linear polarization component in a direction perpendicular to the plane of the drawing. The reflected polarizing beam splitter 72 (hereinafter, referred to as a polarizing beam splitter 72)
A polarization beam splitter 72 for separation).

The coupling optical system applied to the present embodiment transmits observation light having a linear polarization component in a direction parallel to the plane of the drawing and transmits measurement light having a linear polarization component in a direction perpendicular to the plane of the drawing. The reflected polarizing beam splitter 74 (hereinafter, referred to as
A polarization beam splitter 74 for coupling).

The other constructions other than those described above are the same as those of the first embodiment, and the description thereof will be omitted. Next, the operation of the present embodiment will be described with reference to FIGS. FIG. 3 shows an image measurement operation using the observation light, and FIG. 4 shows an inclination angle measurement operation using the measurement light. In addition, during the measurement operation, the observation light and the measurement light always travel in the optical path at the same time, but in the following description, the image measurement operation and the tilt angle measurement operation will be described with reference to different drawings.

As shown in FIG. 3, the observation light of the divergence angle (θ−θ ′) emitted from the illumination unit 30 is transmitted through the half mirror 42 and the collimator lens 44 to the measurement spot 28 a of the measurement object 28. Is irradiated. At this time, specularly reflected light and scattered light (diffraction light) are generated from each point on the measurement object 28 (measurement point 28a). In the image measurement operation, description will be added focusing on scattered light (diffraction light).

The scattered light (diffracted light) generated from each point on the measurement object 28 (measurement point 28a) is captured by the collimator lens 44, becomes parallel light, passes through the half mirror 42, and is coupled. The light is guided into the image unit 32.

The scattered light (diffracted light) guided to the imaging unit 32 passes through the polarization beam splitter 72 for separation, and then passes through the imaging lens 48 for observation light and the polarization beam splitter 74 for coupling to capture an image. The image is formed on the light receiving element 58a of the device 58.

At this time, an image signal corresponding to the amount of light received by the light receiving element 58a is output from the image pickup device 58 to the monitor 60, and an observation image of the measurement object 28 (measurement point 28a) is displayed on the monitor 60. Will be.

As shown in FIG. 4, the measurement light having the spread angle θ ′ emitted from the illumination unit 30 is
And the measurement object 28 via the collimator lens 44
Is irradiated to the measurement point 28a. At this time, specularly reflected light and scattered light (diffraction light) are generated from each point on the measurement object 28 (measurement point 28a). In the tilt angle measuring operation, description will be given focusing on specularly reflected light.

The specularly reflected light generated from the measurement object 28 (measurement point 28a) is taken into the collimator lens 44, becomes convergent light, passes through the half mirror 42, and is guided into the image forming unit 32. Is done.

The specularly reflected light guided to the imaging unit 32 is reflected from the separating polarizing beam splitter 72,
The light is guided through a total reflection mirror 52, a measurement light imaging lens 50, and a total reflection mirror 54. Then, the specular reflection light
After being reflected from the coupling dichroic mirror 56, an image is formed on the light receiving element 58a of the image pickup device 58. In this state, a minute spot corresponding to the size of the minute opening 70a is formed on the light receiving element 58a.

At this time, an image signal corresponding to the amount of light received by the light receiving element 58a is output from the image pickup device 58 to the monitor 60, and a minute spot image is displayed on the monitor 60. During the actual measurement operation, the monitor 60
An observation image of the measurement object 28 (measurement point 28a) and a minute spot image are simultaneously displayed.

However, in this embodiment, since the same light source 66 is used as the light source for the observation light and the measurement light,
The observation image and the minute spot image have the same color. Therefore, the angle calculator 62 applied to the present embodiment calculates the intensity difference between the light amount of the scattered light (diffracted light) focused on the light receiving element 58a and the light amount of the minute spot formed on the light receiving element 58a. Based on the control, control is performed so as to discriminate the observation image and the minute spot image. Note that the method of calculating the inclination angle is the same as that of the first embodiment, and a description thereof will be omitted.

As described above, according to the measuring apparatus of the present embodiment, the image pickup device 58 which does not require two light sources having different wavelength bands and has a wavelength sensitivity band in the visible light range can be prepared. It is possible to realize compactness and low cost. Note that the other effects are the same as those of the first embodiment, and a description thereof will be omitted.

As a modification of the present embodiment, in the optical path between the half mirror 42 and the collimator lens 44, the crystal axis is positioned at 45 degrees with respect to the polarization directions of the observation light and the measurement light.
It is also preferable that a λ / 4 plate is arranged so as to be inclined at an angle, and additionally, the polarizer 68 is rotated by 90 °. That is, the λ / 4 plate is arranged so as to be freely inserted and removed, and the polarization direction of the polarizer 68 is variably configured accordingly. This is for matching the components of the light reflected and transmitted by the polarization beam splitter 72 in the present embodiment. In this case, the measurement object 28 (measurement point 28a) can be illuminated with light having a circularly polarized light component. As a result, the image measurement operation and the tilt angle measurement operation can be performed without being affected by the polarization characteristics of the measurement object 28 (measurement point 28a). Further, improvement of measurement accuracy can be expected only by adding a simple configuration change to the basic configuration of the present embodiment.

Further, as a modified example of the present embodiment, in the optical path of the measurement light (for example, the minute aperture 70a of the λ / 2 plate 70).
It is also preferable to insert a color filter in (in). In this case, the minute spot image and the observation image can be displayed in different colors.

As shown in FIGS. 5 and 6, as a modification of the present embodiment, a slider 76 having an imaging optical system for observation light and an imaging optical system for measurement light is attached to an imaging unit 32.
May be provided.

The slider 76 is slidably controlled in a direction orthogonal to the optical axes of the observation light and the measurement light, and is provided with an observation light imaging optical system or a measurement light imaging optical system depending on the measurement purpose. It is configured so that it can be positioned on the optical axis.

The imaging optical system for observation light, when combined with the collimator lens 44, defines the measurement object 28 (measurement location 28a) and the imaging position I of the measurement unit 34 in an optically conjugate positional relationship. Observation light imaging lens 4
8 and an analyzer 78 (hereinafter, referred to as an observation light analyzer 78) that can transmit only observation light having a linear polarization component in a direction parallel to the sheet of the drawing.

The measuring light image forming optical system, when combined with the collimator lens 44, defines the light source 66 and the image forming position I of the measuring unit 34 in an optically conjugate positional relationship. And an analyzer 80 (hereinafter, referred to as an analyzer for measurement light 80) that can transmit only measurement light having a linear polarization component in a direction perpendicular to the plane of the drawing.

In the measuring apparatus of this modified example, the observation light is focused on the light receiving element 5
8a (see FIG. 5). Also, by driving and controlling the slider 76 and positioning the measurement light imaging optical system in the optical path, the measurement light can be spot-irradiated to the light receiving element 58a of the image pickup device 58 (see FIG. 6).

According to this modification, since there is no need to form an observation optical path and a measurement optical path in the apparatus, adjustment between optical systems (optical axis alignment) can be simplified. Further, since the configuration of the optical system is simplified, the manufacturing cost of the device can be reduced. In addition, since the observation image and the minute spot image can be measured separately, the observation image can be measured without being affected by the optical effect of the minute spot image, and the observation image can be affected by the optical effect. It is possible to measure a minute spot image without any problem. As a result, measurement accuracy can be improved and image processing can be facilitated.

[0063]

According to the present invention, it is possible to provide a measuring device capable of measuring an observation image and an inclination angle of a measurement object in a short time and efficiently with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a measuring device according to a first embodiment of the present invention, and is a diagram for explaining an image measuring operation using observation light.

FIG. 2A is a diagram showing a configuration of a measuring apparatus according to the first embodiment of the present invention, and is a diagram for explaining an inclination angle measuring operation using measuring light, and FIG. FIG. 4 is a diagram for explaining a method of calculating an inclination angle.

FIG. 3 is a diagram showing a configuration of a measuring device according to a second embodiment of the present invention, and is a diagram for explaining an image measuring operation using observation light.

FIG. 4 is a diagram showing a configuration of a measuring device according to a second embodiment of the present invention, and is a diagram for explaining an inclination angle measuring operation using measuring light.

FIG. 5 is a diagram showing a configuration of a measuring device according to a modification of the second embodiment, and is a diagram for explaining an image measuring operation using observation light.

FIG. 6 is a diagram showing a configuration of a measuring device according to a modification of the second embodiment, and is a diagram for explaining an inclination angle measuring operation using measuring light.

FIG. 7A is a diagram showing a configuration of a conventional measuring device,
(B) is a diagram for explaining a method of measuring an inclination angle using a three-point measurement method, (c) is a diagram showing a configuration of an autocollimator, and (d) is a focus used in the autocollimator. The top view of a board.

[Explanation of symbols]

 28 Measurement object 28a Measurement point 30 Illumination unit 32 Imaging unit 34 Measurement unit

Claims (3)

[Claims] An illumination unit capable of simultaneously emitting observation light for observing a measurement object and measurement light for measuring an inclination angle of the measurement object, and the measurement object irradiated with the observation light An imaging unit that forms an observation image light from the measurement image light from the measurement object irradiated with the measurement light at a predetermined imaging position; and an observation image light that is formed at the imaging position. A measuring apparatus comprising: a measuring unit capable of measuring an observation image and an inclination angle of the measurement object based on measurement image light. 2. The imaging unit, comprising: an observation light imaging optical system configured to form the observation light at the imaging position of the measurement unit; and a measurement light configured to form the measurement light at the imaging position. The measurement apparatus according to claim 1, further comprising an imaging optical system for use. 3. The imaging optical system for observation light includes a lens capable of defining an optically conjugated positional relationship between the object to be measured and the imaging position, and the imaging optical system for measurement light. The measuring apparatus according to claim 2, wherein the system includes a lens capable of defining the illumination unit and the imaging position in an optically conjugate positional relationship.