JPH0936036A - Method and apparatus for detecting tilt or height of optical multilayer object - Google Patents

Abstract

(57) [Abstract] (Correction) [Problem] The inclination or height of an optical multi-layer object that can accurately measure the inclination or height of an object having a layered structure such as a semiconductor wafer regardless of the structure or optical characteristics of the object to be measured. A height detection method and apparatus are provided. SOLUTION: Light having high directivity is incident on a surface of an object to be measured having a multilayer structure such as a wafer, and an incident angle of its chief ray is 85 °.
Irradiate obliquely as described above. When the incident angle is 85 ° or more, most of the light is reflected by the surface, and the incident light inside becomes small, so that the information on the surface of the measured object can be accurately obtained. Further, when the irradiation light is S-polarized, the surface reflection is further increased, which enables more accurate measurement. Further, since the direction of regular reflection of the irradiation light incident on the object to be measured is 2α with respect to the inclination α of the object to be measured, this regular reflected light is reflected almost perpendicularly and returned to the original optical path, and the object to be measured is again measured. Then, the specularly reflected light becomes 4α, and the inclination of the object to be measured can be detected with a sensitivity of 4 times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for optically detecting the inclination or height of an optical multilayer object such as a wafer.

[0002]

2. Description of the Related Art A conventional tilt detecting apparatus for an optical multi-layer structure object such as a semiconductor wafer is a first known example.
As described in Japanese Patent No. 170605, the light emitted from the laser diode 2 shown in FIG. 8 is converted into a directional beam by the lens 14 and irradiated onto the wafer 4 from above, and the reflected light is detected by the two-dimensional position detector 20. .

Further, the measuring object is not limited to the optical multi-layer structure object, but a general object distance (height) and inclination measuring device is disclosed in Japanese Patent Laid-Open No. 62-218802 of FIG. 9 which is a second known example. ing. In this known example, the tilt is incident vertically, and is obtained by the second light receiver as in the first known example. The distance (direction perpendicular to the surface of the DUT 6) is determined by the first optical path 9 at an incident angle of 60. The spot irradiated at about ° is imaged on the first detector, and the image formation position is obtained.

[0004]

When the above-mentioned prior art is applied to a pattern formed in a thin film structure on the surface of a wafer such as a semiconductor wafer, or a photoresist coated thereon with a thickness of 1 to several .mu.m. The irradiation light not only reflects on the surface of the DUT but also refracts and enters the inside of the layer structure, and the light reflected by the underlying layer passes through the surface again and is superimposed on the light reflected on the top surface above. To be done. At this time, the light reflected by the uppermost surface and the light reflected by the base surface interfere with each other, and the interference intensity greatly changes with a minute change in the thickness of the film and the incident angle of the irradiation light. When the light is obliquely irradiated as in the distance detecting system of FIGS. 8 and 9, the distribution of the reflected light from the measured object becomes different from the distribution at the time of incidence (for example, Gaussian distribution) as shown in FIG.
Moreover, the distribution varies depending on the layer structure of the object to be measured and the optical constants of the substances forming the object. As a result, an offset occurs in the measurement data each time the object to be measured changes, making accurate absolute value measurement difficult. Further, although the irradiation is performed vertically in the tilt detection of FIG. 9, if the tilt and height detections are applied to the semiconductor exposure apparatus and the semiconductor pattern inspection apparatus, the exposure optical system and the detection optical system overlap with the irradiation optical system, The configuration of the optical system becomes difficult.

The occurrence of a measurement error due to the interference of the above-mentioned optical multi-layered objects becomes a serious problem particularly when the inclination or height of the surface of the object to be measured is measured by the interference method. In the case of the interference method, the slope and phase of the wavefront of the reflected light are obtained from the interference fringes generated by the light reflected on the surface of the object and the reference light, and this represents the inclination and height of the object. However, in the case of a multi-layer structure, as shown in FIG. 4, when the light is incident on the DUT at a normal incident angle of about 0 to 85 °, the light reflected on the surface of the multi-layer structure object or each of the layers inside the layer interferes, and The amplitude and phase of light immediately after the reflection of an object are greatly changed by the thickness of each layer and the change depending on the place. As a result, the interference fringes obtained by superimposing the reference light do not have an accurate sine waveform, and a large error occurs.

The object of the present invention is to solve the above-mentioned conventional problems,
The inclination or height of an optical multi-layered object that enables accurate measurement of at least one of the inclination and height of an object having a layered structure such as a semiconductor wafer regardless of the structure and optical characteristics of the measured object. It is to provide a detection method and an apparatus thereof.

Another object of the present invention is to facilitate mounting on an exposure apparatus and an inspection apparatus.

[0008]

In order to achieve the above object, according to the present invention, light having a relatively high directivity is incident on the surface of an object to be measured having a multi-layer structure such as a wafer, in which the angle of incidence of its chief ray is large. Irradiate at an angle of 85 ° or more. When the incident angle is 85 ° or more, the ratio of the amplitude of the reflected light to the amplitude of the incident light becomes small as shown in FIGS. 5 and 6, most of the light is reflected on the surface, and the incident light inside becomes small. Further, if the amplitude of the light to be radiated is S-polarized, the reflection on the surface will become larger and larger.

The direction of specular reflection of the irradiation light incident on the object to be measured is 2α with respect to the inclination α of the object to be measured. When the specularly reflected light is reflected almost vertically, returned to the original optical path, and then made incident on the object to be measured again, the specularly reflected light becomes 4α as shown in FIG. That is, the specularly reflected light is inclined four times as much as the inclination of the object to be measured.

Further, in the present invention, when interference is used as a method for detecting the inclination and height, the amplitude and phase of the specularly reflected light are increased by increasing the reflection on the surface, in contrast to the conventional problem of using the above-mentioned interference method. It almost represents the information on the surface and is not affected by the thickness of the inner layer or the pattern step.

The amplitude of the light incident on the object to be measured is S-polarized,
Assuming A _S and A _P for P-polarized light, the amplitudes R _S , R _P and D _S , D _P of light reflected and refracted on the surface of an object having a refractive index n are the incident angle θ and the refraction angle ψ (sin ψ = sin θ). / N) is given by the following equation.

[0012]

[Equation 1]

[0013]

[Equation 2]

[0014]

(Equation 3)

[0015]

(Equation 4)

For S-polarized light, the incident light is 0 ° to 60 °, and for P-polarized light, the transmitted light is larger than the surface-reflected light from about 0 ° to 75 °, and the surface-reflected light is reflected from the reflected light from the boundary of the underlying multilayer structure. A large amplitude interference occurs with the light. The amplitude of the surface-reflected light becomes larger when the incident angle is about 85 ° from the above value, but this is an insufficient condition for accurate measurement. The reasons are as follows.

As shown in FIG. 3, the light having the amplitude A incident at the incident angle θ is refracted at the refraction angle ψ and the amplitude D, and is reflected by the amplitude reflectance R _b on the base, the amplitude of the reflected light is D · R. _b .
Here, assuming that the amplitude of the incident light A is 1, D is the amplitude transmittance. Therefore, when the light reflected by the base passes through the surface, its amplitude becomes R _b D ₂ . On the other hand, light incident with an amplitude A (= 1) is reflected by the surface and its amplitude becomes R. Here, R and D are expressed by R _S , D _S and R _P , D _P depending on whether the polarization of incident light is S or P, and the above (Formula 1) to (Formula 4) are established. The light R ₀ reflected on the surface and the light R ₁ reflected on the base layer overlap when the layer thickness d is small, and as a result, light having a complex amplitude A _R shown by the following equation is obtained.

[0018]

(Equation 5)

Here, λ is the wavelength of light used for measurement. It can be seen that the phase of A _R changes from (Equation 5) even if the film thickness d shown in FIG. 3 changes slightly (change in length one digit below the wavelength). Therefore, the relationship between the incident angle θ and R and D is S
5 and 6 for P-polarized light and P-polarized light, respectively, and the amplitude ratio R _b · D ² of the second term to the first term of (Equation 5) becomes a noise component for easier understanding from this graph.
If / R is obtained, the degree of error on the measurement can be evaluated. Then, considering the case of R _b = 1 as the worst case, FIG. 7 shows D ² / R obtained for the incident angle θ and for two polarized lights. Since D ² / R becomes a noise (error) component in various detection methods, this value is set to 5
It can be seen that it is necessary to set the incident angle to 85 ° or more in order to keep the ratio below%. Further, it can be seen from FIG. 7 that if the light enters in the S-polarized state, the noise is further reduced, and in order to keep the above value at 5% or less, 82 ° or more is sufficient.

The method of reflecting twice on the surface of the object to be measured improves the detection sensitivity of the inclination and height as described above, and enables highly accurate measurement.

Further, in the detection by the interferometric method, the reflected light from the base surface is superimposed on the interference pattern and disturbs the pitcher phase of the interference fringes, but when the incident light is 85 ° or more and the S-polarized light is further used, this influence is almost caused as described above. Can be eliminated, and highly accurate detection becomes possible. Furthermore, by making the optical path of the reference light used for this interferometric measurement almost the same as the measuring light, stable and highly accurate measurement that is hardly affected by the measurement environment such as air fluctuation is realized.

When the above-described tilt and height measuring method is applied to the semiconductor exposure apparatus, there is no spatial interference with the exposure optical system,
Moreover, since it is possible to detect the tilt and height of the exposed portion of the wafer with high accuracy as described above, the tilt and height of the wafer can be controlled from this detected value, and the wafer surface can be set as the exposure image plane. It can be precisely matched, and the submicron pattern can be accurately printed over the entire exposed area.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention is shown in FIG. FIG. 1 is for detecting the inclination of the exposure area of the wafer in the exposure state of the semiconductor exposure apparatus. 81 is an exposure illumination system, 9 is a reticle, 8 is a reduction exposure lens,
The pattern of the reticle 9 is exposed on the wafer 4. At this time, the surface of the photoresist applied to the surface of the wafer is not necessarily flat due to the waviness of the wafer, uneven thickness, and flatness of the wafer chuck. Then, the laser light emitted from the first semiconductor laser is made into a thin parallel beam by the collimator lens 11 and is incident on the resist surface of the wafer and the exposure region at an incident angle of 85 ° or more through the mirror 13. The reflected light is condensed by the mirror 210 and the condenser lens 20 on the optical position detector 3 ', and the condensed position is detected. If the exposure area is inclined by α, the specularly reflected light is inclined by 2α, so that the focal spot of the optical position detector is displaced by 2αf when the focal length of the condenser lens is f. Therefore, the detected signal is sent to the processing circuit 5 ', and the tilt mechanism equipped with the wafer chuck is driven to control so that the photoresist surface on the wafer coincides with the reticle pattern image surface. At this time, if the semiconductor laser is arranged so that the semiconductor laser emission light 161 'is incident on the wafer surface as S-polarized light, more accurate tilt detection can be performed as described above. In the embodiment of FIG. 1, the optical position detector 3 '
Is a type that detects both x and y directions, and tilts in two directions can be obtained with one detection system.

A second detection system may be provided in the direction perpendicular to the paper surface of FIG. 1 to detect the tilts in the x and y directions separately. The light source is not limited to the semiconductor laser as long as it can irradiate the wafer with light having relatively high directivity.

FIG. 2 shows an embodiment of the present invention, and the same reference numerals as those in FIG. 1 represent the same items. The light emitted from the semiconductor laser 1 is incident on the wafer at an incident angle of 85 ° or more, and a light source image is formed in the exposure area on the wafer by the condenser lens 11 '. The reflected light is condensed on the optical position detector 3 ″ by the mirror 210 and the lenses 21 and 22. If the wafer surface is in the image forming position of the resist pattern of the exposure optical system, the center of the optical position detector 3 ″ is displaced, and if the wafer surface is vertically displaced, the center of the optical position detector 3 ″ is displaced laterally. By sending the 3 ″ detection signal to the processing circuit 5 ′ and driving and controlling the wafer upper and lower tables, correct focusing is always possible. If the polarization of the laser light is made to enter the wafer surface as S-polarized light, the height of the photoresist surface can be obtained more accurately.

FIG. 10 shows an embodiment of the present invention, and the same part numbers as in FIG. 1 represent the same parts. The parallel light obtained by the collimating lens 11 is a beam splitter 19 '.
And enters the photoresist surface of the wafer at an incident angle of 85 ° or more, for example, 87 °. The specularly reflected light is a plane mirror 14.
Is incident on the photoresist surface regularly, is reflected by the photoresist surface again, is reflected by the beam splitter 19 ', is condensed by the condenser lens 20 on the optical position detector 3', and the position of the condensed spot is detected. To be done. When the incident angle on the wafer is 87 ° and the S-polarized light is 16 _S as shown in FIG. 11, D _S ² / R _S is 0.0065, that is, 0.6 as shown in FIG.
Light 162, which is 5% and almost enters the photoresist
1 is negligible, and even if the underlayer is uneven as shown in FIG. 11, it is hardly affected by the unevenness and specular reflection is performed as parallel light. Therefore, a sharp spot light having a high light condensing degree is obtained at the light position detector 3 '. Further, in this embodiment, as shown in FIG. 12, the light is reflected vertically by the plane mirror 14 and is incident on the wafer again. Therefore, when the wafer is inclined from 4 to 4 ′ by α, the light finally returned to the optical position detector. Is inclined by 4α, and the light position can be detected with a sensitivity twice as high as that of the embodiment of FIG. As a result, it becomes possible to detect an inclination that is very excellent in both S / N and sensitivity.

FIG. 13 shows an embodiment of the present invention, and the same reference numerals as those in FIG. 2 represent the same items. The condensed beam obtained by the condenser lens 11 'is substantially condensed at the irradiation position A on the wafer. The incident angle is 85 ° or more. The specularly reflected light is collimated by the collimator lens 141 and is incident on the plane mirror 14 substantially vertically. The reflected light passes through almost the same optical path as the outward path, is substantially condensed on the wafer, is reflected again, passes through the beam splitter 12, and is condensed on the optical position detector 3 ″ by the condenser lens 22. FIG. 14 illustrates the position of the focusing point near the wafer when the surface (reflection surface Σ) 4 of the wafer shown by the solid line changes to 4 '(reflection surface Σ) shown by the dotted line. Consider the case where light is condensed at point A when the reflection surface is Σ for both the forward path and the return path. When the reflection surface is Σ ', the Σ' surface becomes a mirror surface, and point A on the outward path forms a mirror image at point A '. The light emitted from the point A'is condensed by the plane mirror 14 of the lens 141 to A "in the returning path. At this condensing point, Σ'becomes a mirror surface, and a mirror image of the point A "is made on A"". Therefore, from the return path, the light enters the condenser lens 22 as if the light emitted from A ″ ″, and the light is focused on the image position A ″ ″ on the optical position detector 3 ″. Let Δh be the distance between Σ and Σ ′, that is, the vertical movement of the wafer.

[0028]

(Equation 6)

Then, the light emitting point position on the return path is shifted by 4 times (4Δh) the displacement amount of the wafer (see FIG. 14). As a result, a displacement amount twice as large as that in the embodiment of FIG. 2 is detected by the optical position detector 3 ″. As a result, it is possible to detect height with high sensitivity and high S / N.

FIG. 15 shows an embodiment of the present invention. FIG.
The same number as represents the same item. The light emitted from the coherent light source 1 such as a laser becomes parallel light 15 by the collimator lens 11 and enters the prism 10. The prism 10 splits the incident light 15 into two parallel beams 16 and 17.
The two parallel beams have a constant angle θ ₀ −θ ₁ with each other so that they overlap at 0 point. One of the parallel beams 16 is incident on the wafer at an incident angle θ ₁ , and the other is a reference beam, which advances without irradiating the wafer at an angle of θ ₀ (> 90 °) with respect to a vertical line standing on the wafer. The parallel beam 16 reflected by the wafer enters the plane mirror 14 almost perpendicularly, enters the wafer again, travels in the reverse direction, is reflected by the beam splitter 12, becomes a parallel beam after passing through the lenses 21 and 22, and is a one-dimensional sensor. Three
Incident on. On the other hand, the reference light is directly incident on the plane mirror 14 from the point 0 substantially perpendicularly, and after being reflected, is traced backward in the forward path, is also incident on the one-dimensional sensor 3, and generates an interference fringe with one beam reflected by the wafer. To do. A pinhole 23 and a wedge glass 26 are arranged on the return path of the light reflected by the wafer. The pinhole 23 is also in the reference optical path and plays a role of removing noise light reflected on the back surface of the optical component.
On the other hand, the wedge glass 26 refracts the light reflected by the wafer, thereby forming an image of the wafer irradiation position on the one-dimensional sensor and overlapping the reference light. On the one-dimensional sensor, interference fringes having an intensity as shown by the solid line in FIG. 16 with respect to the sensor array direction X are detected. When the wafer is inclined by Δθ about the wafer irradiation position (X = 0) as shown by the dotted line, the detected interference fringes are as shown by the dotted line in FIG. That is, the intensity at X = 0 hardly changes, but it changes from the stripe pitch P to P ′. That is, since the intensity I (X) of the interference fringe is given by (Equation 7), the relationship between the pitch P and the inclination Δθ can be obtained by this equation (Equation 8).

[0031]

(Equation 7)

[0032]

(Equation 8)

In the above (Equation 7), M is a magnification for forming an image of the irradiation position on the wafer on the one-dimensional sensor, but for the sake of simplicity, it is assumed that the wedge angle of the wedge glass is 0 degree (wedge). Without glass).

The second term in the cosine of (Equation 7) represents the change in the interference fringes when the wafer surface changes by ΔZ,
As shown in FIG. 17, when the wafer surface changes by ΔZ, the pitch of the interference fringes does not change and the phase shifts. Therefore, in the present embodiment, the interference fringes obtained by the one-dimensional sensor 3 are sent to the processing circuit 5, where the interference fringe pitch and phase can be obtained.
The height and inclination of the wafer surface are required at the same time.
Further, in the present embodiment, it is possible to set the incident angle θ ₁ to 87 to 89 degrees, and if S polarized light is used for the irradiation light, as is apparent from FIG. And the height can be accurately obtained. Further, in the present embodiment, the reference light passes through almost the same optical path as the wafer irradiation light, and the optical components used are all common except for the reflection on the wafer surface, so that they are hardly affected by air fluctuations. It can realize stable measurement.

[0035]

As described above, according to the present invention, the inclination or height of an optical multi-layer object such as a wafer having various multi-layer structures during the semiconductor circuit manufacturing process can be accurately measured without being influenced by the multi-layer structure. It becomes possible to accurately perform tilt control for focusing and aligning the wafer surface with the image plane in the semiconductor exposure apparatus.
A high NAi line reduction exposure apparatus used for exposure of a line width circuit pattern of 0.8 μm or less, particularly 0.5 μm or less,
For the reduction of the exposure focus margin due to the shallow depth of focus expected to occur in the excimer laser reduction exposure apparatus,
It has a very remarkable effect.

[Brief description of drawings]

FIG. 1 is a device configuration diagram showing an embodiment of the present invention.

FIG. 2 is a device configuration diagram showing an embodiment of the present invention.

FIG. 3 is a diagram for explaining the principle of the present invention.

FIG. 4 is a diagram illustrating a conventional problem.

FIG. 5 is a characteristic diagram illustrating the principle and effect of the present invention.

FIG. 7 is a characteristic diagram illustrating the principle and effect of the present invention.

FIG. 8 is a diagram for explaining a conventional technique.

FIG. 9 is a diagram for explaining a conventional technique.

FIG. 10 is a configuration diagram showing another embodiment of the present invention.

FIG. 11 is a diagram for explaining the embodiment of FIG.

FIG. 12 is a diagram for explaining the embodiment of FIG.

FIG. 13 is a block diagram showing another embodiment of the present invention.

FIG. 14 is a diagram for explaining the embodiment shown in FIG.

FIG. 15 is a block diagram showing another embodiment of the present invention.

16 is a diagram for explaining the embodiment shown in FIG.

FIG. 17 is a diagram for explaining the embodiment shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light source, 11 ... Collimating lens, 11 '... Condensing lens, 20 ... Condensing lens, 21, 22 ... Lens, 13, 14, 210 ... Mirror, 16, 19 ... Half mirror, 3 ... One-dimensional sensor, 3 ′, 3 ′ ′ ... Optical position detector, 4 ... Wafer, 5, 5 ′ ... Processing circuit, 7 ... Stage, 8 ... Reduction exposure lens, 81 ... Illumination, 9 ... Reticle.

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[Procedure amendment]

[Submission date] July 24, 1996

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of drawings]

FIG. 1 is a device configuration diagram showing an embodiment of the present invention.

FIG. 2 is a device configuration diagram showing an embodiment of the present invention.

FIG. 3 is a diagram for explaining the principle of the present invention.

FIG. 4 is a diagram illustrating a conventional problem.

FIG. 5 is a characteristic diagram illustrating the principle and effect of the present invention.

FIG. 6 is a characteristic diagram illustrating the principle and effect of the present invention.

FIG. 7 is a characteristic diagram illustrating the principle and effect of the present invention.

FIG. 8 is a diagram for explaining a conventional technique.

FIG. 9 is a diagram for explaining a conventional technique.

FIG. 10 is a configuration diagram showing another embodiment of the present invention.

FIG. 11 is a diagram for explaining the embodiment of FIG.

FIG. 12 is a diagram for explaining the embodiment of FIG.

FIG. 13 is a block diagram showing another embodiment of the present invention.

FIG. 14 is a diagram for explaining the embodiment shown in FIG.

FIG. 15 is a block diagram showing another embodiment of the present invention.

16 is a diagram for explaining the embodiment shown in FIG.

FIG. 17 is a diagram for explaining the embodiment shown in FIG.

[Description of Reference Signs] 1 ... Light source, 11 ... Collimating lens, 11 ′ ... Condensing lens, 20 ... Condensing lens, 21, 22 ... Lens, 13, 14, 210 ... Mirror, 16, 19 ... Half mirror, 3 ... One-dimensional sensor, 3 ′, 3 ″ ... Optical position detector, 4 ... Wafer, 5, 5 ′ ... Processing circuit, 7 ... Stage, 8 ... Reduction exposure lens, 81 ... Illumination, 9 ... Reticle.

Claims (10)

[Claims] 1. A tilt of an optical multi-layered object, characterized in that an incident angle of the irradiating light is set to 85 degrees or more in a method of detecting a tilt or a height from information of reflected light of light irradiated on an object to be measured. Or how to detect height. 2. The method for detecting the inclination or height of an optical multi-layered object according to claim 1, wherein the irradiation light is linearly polarized light composed only of S-polarized light components. 3. The specularly reflected light is reflected almost vertically by a fixed plane mirror, is irradiated again to the object to be measured, and only the specularly reflected light is taken out to detect the tilt or height of the object to be measured. The method for detecting the inclination or height of an optical object according to claim 1, characterized in that: 4. The specular reflection light is caused to interfere with a fixed reference light that is coherent with the specular reflection, and the inclination is detected from the pitch of the interference information, and the height information is detected from the pitch and the phase. A method for detecting the inclination or height of an optical multilayer object. 5. The inclination of the optical multi-layered object according to claim 4, wherein the reference light passes through substantially the same optical path as the irradiation light and the specular reflection light that interfere with the reference light. Height detection method. 6. A light source, an irradiating means for making the light emitted from the light source incident on the surface of the object to be measured having an optically multi-layered structure at an incident angle of the chief ray of 85 ° or more, and a positive object to be measured. Inclination of an optical multi-layered object, comprising detection means for detecting information of reflected light and a processing circuit for deriving the inclination or height of the object to be measured from the signal obtained by the detection means. Or height detector. 7. The tilt or height detecting device for an optical multilayer object according to claim 6, wherein said light source or irradiating means is provided with S-polarizing means for irradiating the light to be measured with S-polarized light. . 8. A light source, an irradiating means for making the light emitted from the light source incident on the surface of the object to be measured having an optically multi-layered structure at an incident angle of the chief ray of 85 ° or more, and a positive object to be measured. Reflecting and irradiating means for reflecting the reflected light almost vertically and irradiating the object to be measured again, detecting means for detecting the information of the light specularly reflected again by the object to be measured, and detecting from the signal obtained by the detecting means. An inclination or height detection device for an optical multi-layered object, comprising: a processing circuit for deriving the inclination or height of a measurement object. 9. A reference light generating means for generating a fixed reference light that is coherent with the regular reflected light, the regular reflected light and the reference light being detected by the detecting means in the form of interference fringes, 7. An optical multilayer object inclination or height detection device according to claim 6, further comprising a processing circuit for deriving an inclination or height from the obtained pitch and phase of the interference signal. 10. The reference light generated by the reference light generating means is configured so as to pass through substantially the same optical path as the irradiation light and the specular reflection light that interfere with the reference light, except that the reference light is not reflected by the surface of the object to be measured. 10. The method according to claim 9, wherein
A device for detecting the inclination or height of an optical multilayer object as described above.