JP3075243B2 - Optical characteristic measuring unit, transmission characteristic measuring device, reflection characteristic measuring device, ellipsometer, transmission characteristic measuring method and reflection characteristic measuring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical characteristic measuring unit suitable for measuring optical characteristics of an optical element,
The present invention relates to an optical characteristic measuring device using this unit and a method for measuring optical characteristics using this unit. In addition,
Here, the optical characteristics include, for example, transmittance, reflectance,
And a characteristic selected from a phase change of light in transmission or reflection.

[0002]

2. Description of the Related Art As typical examples of optical characteristics of an optical element, there are a transmittance and a reflectance. In addition, the transmittance and the reflectance include a relative transmittance and a relative reflectance represented by a relative value with respect to a reference object that is previously priced, and an absolute transmittance and an absolute reflectance obtained from the element itself. Further, changes in transmittance and reflectance depending on wavelength are called spectral transmittance and spectral reflectance, respectively.

When measuring the transmittance and the reflectance, the above-mentioned spectral transmittance and the spectral reflectance are most commonly measured.
When measuring the transmittance and the reflectance, the transmittance and the reflectance with respect to the change in the incident angle of light are often measured.

Further, as other examples of the optical characteristics of the optical element, there are a refractive index of a member constituting the optical element and an optical constant of a thin film. Usually, the refractive index and the optical constant depend on the incident angle dependence of the phase change of light (hereinafter, referred to as “the phase change of light in transmission”) due to the transmission of light through the object or the object to be measured. It can be obtained by measuring the incident angle dependence of a change in the phase of light due to reflection of light (hereinafter, referred to as “phase change of light in reflection”) and analyzing the measurement result.

[0005] The measurement of transmittance and reflectance is usually performed using a commercially available spectrophotometer and a dedicated optical system attached to the spectrophotometer. The phase change of light in transmission or reflection is usually performed using an ellipsometer. Hereinafter, those conventional examples will be described.

[0006] As a conventional apparatus for measuring the transmittance of an optical element using a spectrophotometer and also taking into account the dependence on the incident angle of light, there is the following apparatus. FIG. 18 is an explanatory diagram thereof. However, details of the spectrophotometer (monochromator section, light receiving section, etc.) are not shown.

In this conventional device, the device under test 11 is fixed to the goniometer 13. The DUT 11 is rotated by a goniometer 13 to a predetermined angle. Therefore, the amount of light transmitted through the object 11 (the amount of light to be measured) can be measured while changing the incident angle θ. Further, the light amount (reference light amount) in a state where the DUT 11 is not installed in the measurement system is measured. From these test light amounts and reference light amounts, the dependence of the transmittance on the incident angle can be measured.

As a conventional apparatus for measuring the absolute reflectance of an optical element, for example, Japanese Industrial Standard (JIS K0115)
An apparatus using a method called a VN method defined in US Pat. FIGS. 19A and 19B are explanatory diagrams thereof.

In this VN method, three mirrors M1 to M3
Is used. Then, as a first state, these mirrors M1 to M3 are arranged so that the optical path is V-shaped (FIG. 19A). The light amount (reference light amount) output from the optical system is measured by a light receiving unit (not shown). This reference light amount is represented by Ir = Io × R1 × R2 × R3. Here, Io is the amount of incident light, and R1 to R3 are mirrors M
It is the reflectance of each of 1 to M3.

Next, as shown in FIG. 19B, the DUT 11 is inserted into the optical path. However, these mirrors M
The mirrors M2 and M3 are moved or rotated so that an N-shaped optical path is formed by 1 to M3 and the DUT 11.
Then, the light quantity (test light quantity) output from the optical system is measured by the light receiving unit. The amount of light to be detected is Is = Io × R
It is represented by 1 × R2 × R3 × Rs. Here, Rs is the absolute reflectance of the surface to be measured of the DUT 11.

The light quantity to be measured is the sum of the reference light quantity and the absolute reflectance of the surface to be measured.
Is determined by Rs = Is / Ir.

Usually, when the above-described transmittance measurement and reflectance measurement are performed, the double beam method is employed to improve the measurement accuracy. That is, the light of the light source is divided into light traveling on a path including the object to be measured and light traveling on another path toward the light receiving unit. Then, the light passing through the other path is monitored to obtain information such as the intensity fluctuation of the light source. The measurement result of the device under test is corrected based on the information obtained in this manner, thereby improving the measurement accuracy.

Further, as a conventional apparatus for measuring the relative reflectance, there is the following apparatus. FIG. 20 (A) and (B)
FIG.

In the case of this device, the mirrors M1 and M2 are arranged in a C shape. However, mirrors M1 and M2 are
The respective reflection surfaces are arranged so as to be opposite to each other, not to the other mirror. C-shaped mirror M1,
The reference object 15 (see FIG. 20A) or the DUT 11 (see FIG. 20B) is placed above M2. After the measurement light is incident on the mirror M1, the light passes through the reference object 15 (or the DUT 11) and the mirror M2, and is received by a light receiving unit (not shown).
Leads to. The light amount Ir when the reference object 15 is placed above the C-shape and the light amount Is when the object 11 is placed are measured. Relative reflectance is R, similar to the absolute reflectance.
It is determined by s = Is / Ir.

When performing ellipsometry using an ellipsometer, it is necessary to irradiate the object to be measured at an arbitrary angle and receive the reflected light at this time. Be taken. FIG. 21 is an explanatory diagram thereof.

The device under test 11 is placed on a gonio stage 17. The light source 19 is fixed so that its position does not change. The light source unit 19 includes, for example, a light source 19a,
Wavelength filter 19b, condensing optical system 19c, and polarizer 1
9d. The light receiving section 21 is fixed to a stage 23 that rotates coaxially in synchronization with the rotation of the gonio stage 17. The light receiving unit 21 is, for example, an analyzer 21
a, a condenser optical system 21b and a light receiving element 21c. The angle of incidence of the DUT 11 on the test surface 11 a is changed by rotating the goniometer 17. When the incident angle is θ, the stage 23 to which the light receiving unit 21 is fixed rotates by 2θ and receives light from the DUT 11. Therefore, photometry can be performed while changing the incident angle.

In order to calculate the phase change of light from information measured using an ellipsometer, a calculation theory and a method unique to ellipsometry are used. This is described in, for example, Reference 1 (Optical Measurement Handbook, supervised by Toshiharu Tayuki, Asakura Shoten), but is not directly related to the description of the present application.
Here, the description is omitted.

[0018]

Conventionally, there has been the above-mentioned apparatus as an optical characteristic measuring apparatus.
There were the following problems.

First, in the case of the absolute reflectance measuring apparatus described with reference to FIG. 19, the reflectance cannot be measured by changing the incident angle. In order to realize this, it is necessary to prepare a VN optical system for each incident angle. Also,
Even if a VN optical system having a different incident angle is prepared, it is possible to measure only a predetermined discrete incident angle. That is, it is impossible to measure the reflectance at an arbitrary incident angle and the reflectance while continuously changing the incident angle.

Also, in the case of the relative reflectance measuring device described with reference to FIG. 20, the reflectance cannot be measured by changing the incident angle. In order to realize this, it is necessary to prepare a C-shaped optical system for each incident angle.
Further, even if a C-shaped optical system having a different incident angle is prepared, it is only possible to measure a discrete incident angle that is planned in advance. That is, it is impossible to measure the reflectance at an arbitrary incident angle and the reflectance while continuously changing the incident angle.

In each of the apparatus described with reference to FIG. 19 and the apparatus described with reference to FIG. 20, every time the measurement is performed while changing the incident angle, the VN optical system or the C-shaped It is necessary to replace the optical system and adjust the replaced optical system. In addition, since the optical system is replaced, strictly, optical characteristics such as an optical path difference, an aberration, a focal length, and a light amount change every time.

In the case of using an ellipsometer, a structure for moving the light receiving section while moving the object to be measured is required, so that the measurement becomes unstable due to mechanical causes. In addition, since the light receiving unit is moved to a different position, it is difficult to improve the measurement accuracy because it is affected by, for example, the magnetic field distribution. In addition, due to the structure, the installation area of the device also increases.

Also, the ellipsometer cannot basically perform double beam photometry. Therefore, it is not possible to compensate for the intensity fluctuation and the polarization fluctuation of the light source during the measurement. Therefore, it is difficult to increase the measurement accuracy.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and accordingly, it is an object of the present invention to provide an optical system which does not change the optical characteristics or the position of the light receiving unit, and changes the transmittance while arbitrarily changing the incident angle. It is an object of the present invention to provide an optical characteristic measuring unit capable of easily measuring at least one of light, reflectance, and phase change of light in transmission or reflection as compared with the related art.

[0025]

(A) Therefore, an optical characteristic measuring unit according to the present invention has the following configuration. The description will be made with reference to FIG. Note that FIG.
FIG. 1 is a diagram showing a basic configuration of an optical characteristic measuring unit 30 of the present invention.

The optical characteristic measuring unit 30 includes first to fourth reflecting surfaces M1 to M4 for sequentially reflecting incident light,
A reflection surface rotating device 31 for rotating the reflection surface M1 and the fourth reflection surface M4, and an object to be measured 33 (including a reference object) are inserted between the second reflection surface M2 and the third reflection surface M3. And an object moving device 35 for putting out. Further, a reflection surface moving device 37 (details will be described later) is provided.

The first to fourth reflecting surfaces M1 to M4
In such a manner that the optical path passing through these reflecting surfaces M1 to M4 is N-shaped, and the incident light L incident on the first reflecting surface M1 is
The first light and the light L2 emitted from the fourth reflection surface M4 are arranged coaxially. However, the N-shape also includes a substantially N-shape. In the example of FIG. 1, the optical path is N-shaped when viewed from the back of the drawing.

Further, the first and fourth reflecting surfaces M1, M
4 are arranged such that the reflection surface is perpendicular to a plane including the N-shaped optical path.

Further, a line segment connecting the incident point A of the incident light L1 on the first reflecting surface M1 and the emission point D of the emitted light L2;
When the intersection of the light beam trajectory BC traveling from the second reflecting surface M2 to the third reflecting surface M3 is defined as the center O of the optical system, the second reflecting surface M2 is defined by the center O of the optical system and the first reflecting surface. It is constituted by a first spheroid having a focal point at the incident point A of the incident light L1 on the surface.

Further, the third reflecting surface M3 is constituted by a second spheroidal surface whose focal point is the center O of the optical system and the emission point D of the emitted light L2.

Further, the reflecting surface rotating device 31 is moved at the respective positions (specifically, points A and D in FIG. 1) of the first and fourth reflecting surfaces M1 and M4, respectively. The first and fourth reflecting surfaces are rotated in association with each other about an axis perpendicular to a plane including the optical path (an axis perpendicular to the plane of FIG. 1).

The first and fourth reflecting surfaces M1, M4
The direction and amount of rotation are determined so that the incident light L1 and the reflected light L2 can be made coaxial. Therefore, the directions of rotation of the two reflecting surfaces M1 and M4 can be either the same or opposite. Further, both reflecting surfaces M1,
The rotation amount of M4 may be the same or different. Further, the rotation in conjunction with the rotation may be either synchronous rotation or non-rotation. However, typically, they rotate synchronously.

Further, the object moving device 35 is connected to the DUT 3
The object 33 is placed on the second and third reflecting surfaces M2 and M3 such that the third surface 33a of the third object is located at a position including the center O of the optical system.
This is an apparatus for selectively forming an inserted state inserted between them and a non-inserted state not inserted.

(B) In the optical characteristic measuring apparatus of the present invention,
The following operation is obtained.

Consider a line segment OH orthogonal to the line segment AD connecting the incident point A and the output point D at the center O of the optical system. This line segment OH and the second reflecting surface M2 to the third reflecting surface M3
The angle between the trajectory BC of the light traveling toward and is θ. In the present invention, the measured surface 33a of the measured object 33 is located at the center O of the optical system.
The first state in which the device under test 33 is inserted between the second and third reflecting surfaces can be formed so as to be a position including. Then, in this first state, the angle θ is
This is the angle of incidence of light on a.

In the apparatus of the present invention, the first reflecting surface M1 can be rotated about the above-mentioned predetermined rotation axis, and the second reflecting surface M2 is formed of a predetermined spheroid. Therefore, by rotating the first reflecting surface M1, the incident angle θ of the light with respect to the object to be measured can be arbitrarily changed (including the case of being continuous). about this,
The details will be described below.

FIG. 2 shows that the DUT 33 is connected to the second and third
When the optical system is inserted between the reflective surfaces M2 and M3 as described above, the optical system is configured by the first reflective surface M1, the DUT 33, and the second reflective surface M2 configured by a spheroid. FIG. However, here, an elliptical model is considered as the second reflection surface M2. That is, the spheroid is actually a reflection surface formed by a locus obtained by rotating the ellipse in FIG. 2 by a necessary angle around the x-axis in FIG.
Here, an elliptical model is considered. FIG. 2 corresponds to a diagram in which a part of FIG. 1 is shown upside down.

The first reflecting surface M by the reflecting surface rotating device 31
The angle when 1 is rotated is φ. Then, the angle φ and the incident angle θ of light to the DUT 33 have the following relationship.

Assuming that the angle between the light incident on the object 33 and the line segment AO is ψ, ψ = π / 2-θ. Ellipse M
2 is the eccentricity, and the coordinates of the focal point of the ellipse M2 are (−
c, 0) and (c, 0). Then, the tangent of φ and ψ is expressed by the following equations (1) and (2), respectively.

Tan φ = y / (c + x) (1) tanψ = y / (c−x) (2) From these expressions, x and y are represented by using φ and ψ, respectively. Equations (3) and (4) are obtained.

X = c (tanφ−tanψ) / (tanφ + tanψ) (3) y = 2c (tanφtanψ) / (tanφ + tanψ) (4) Here, the elliptic equation and parameters are as follows. Place.

(X / a) ² + (y / b) ² = 1 (5) e ² = (a ² + b ² ) / a ² (6) c ² = a ² + b ^2. (7) By substituting equations (3) and (4) into equation (5) and further solving tan ｔ using the relationship of equations (6) and (7), the following equation is obtained. Can be

Tanψ = {(1-e ² ) ² tan φ ± {2 · e (1-e ² ) tan ² φ} / (1-e ² ) ² -4e ² tan φ} (8) 8) using the relationship of tanψ = cotφ,
Solving for φ gives the following equation:

Θ = arctan {(1-e ² ) ² −4e ² tan φ} / {(1-e ² ) ² tan φ ± {2 · e (1-e ² ) tan ² φ} (9) As can be seen from the equation (9), the incident angle θ of light to the measured surface 33a can be changed by the angle φ at which the first reflecting surface M1 is rotated. Of course, since the incident point A and the center O of the optical system are located at the focal point of the ellipse M2, the center O of the optical system does not move even if φ is changed due to the nature of the ellipse, and the length of the optical path ABO is long. No change. This means that even if the first reflection surface M1 is rotated, the optical system preserves the optical path length, the focal length, the aberration, and the like. Therefore, without changing the optical path length, the focal length, the aberration, and the like, the optical characteristics such as the transmittance and the reflectance in consideration of the incident angle dependency can be measured.

Further, in the optical characteristic measuring unit of the present invention, the first reflecting surface M1 and the fourth reflecting surface M4 can be moved in conjunction with each other, so that the following effects can be obtained. This description will be made again with reference to FIG.

When the first reflecting surface M1 is rotated by an angle φ,
As described above, the incident angle θ of light on the surface to be measured (the center O of the optical system) of the object to be measured 33 changes according to the above equation (9). The light passing through the center O of the optical system is reflected by the third reflecting surface M
After being reflected by 3, the light reaches the fourth reflection surface M4.
The fourth reflecting surface M4 is formed by the reflecting surface rotating device 31.
It can be rotated by an arbitrary angle in conjunction with the first reflection surface M1. Therefore, the incident light L1 and the output light L2 can be made coaxial. This is a light receiving unit (not shown)
Can be fixedly arranged at a subsequent stage of the fourth reflection surface M4 and on an extension of the line segment AD.

Further, the first and fourth reflecting surfaces M1 and M4
By simply rotating, it is possible to measure the optical characteristics while changing the incident angle. Therefore, the replacement of the optical system and the adjustment of the replaced optical system, which are problems in the conventional apparatus, need not be performed in the apparatus of the present invention.

In the optical characteristic measuring unit according to the present invention, the object 33 can be moved in and out by the object moving device 35. Therefore, although details will be described later, various optical characteristics such as transmittance, reflectance, and phase change of light in transmission and reflection can be measured.

(C) By using the optical characteristic measuring unit of the present invention as follows, for example, the transmittance and / or phase change in transmission of an object to be measured can be measured while changing the incident angle. FIGS. 3A and 3B are explanatory diagrams thereof.

First, a state in which the object to be measured is not inserted into the optical system is formed by the object moving device 35 (FIG. 3A).
Then, the intensity of the emitted light L2 is measured while appropriately rotating the first and fourth reflection surfaces M1 and M4 by the reflection surface rotating device 31. This process is referred to as a first process. In addition,
While appropriately rotating the two reflecting surfaces M1 and M4, the first reflecting surface M1 is rotated, and the incident light L1 and the outgoing light are changed so that the angle of incidence on the DUT 33 can be changed as desired. This means that the fourth reflection surface M4 is rotated so that L2 is coaxial (the same applies hereinafter).

Next, the object to be measured is moved by the object moving device 35 so that the surface to be measured 33a of the object to be measured 33 is located at a position including the optical system center O (hereinafter, this position is also referred to as a "predetermined position"). The object 33 is moved to the second and third reflecting surfaces M2 and M3.
The state inserted between them is formed (FIG. 3B). And
The first and fourth reflecting surfaces M by the reflecting surface rotating device 31
1, while appropriately rotating M4, the intensity of the emitted light L2 is measured. This process is referred to as a second process.

However, any of the first processing and the second processing may be performed first.

Next, the transmittance of the object and / or the phase change of the light in the transmission are measured based on the intensity of the emitted light measured in each of the first processing and the second processing.

This will be described in more detail. FIG.
Assuming that the light amount of the emitted light L2 depending on the incident angle θ obtained in the first processing shown in FIG.
(Θ) is represented by the following equation.

Ir (θ) = Io × R1 (θ) × R2 (θ) × R3 (θ) × R4 (θ) (10) where Io is the amount of incident light, and R1 (θ) to R4 (θ). ) Is the reflectance of each reflecting surface at an angle θ.

Further, the light quantity of the outgoing light L2 depending on the incident angle θ obtained in the second processing shown in FIG.
Assuming that (θ), Is (θ) can be expressed by the following equation.

Is (θ) = Io × R1 (θ) × R2 (θ) × R3 (θ) × R4 (θ) × Rs (θ) (11) where Rs (θ) is the angle θ Is the transmittance of the object 33 to be measured.

In the light quantity Is (θ) measured in the second process, a component (ie, Rs
The components other than (θ)) are the same as the components measured in the first processing. Therefore, assuming that the transmittance of the measured object in consideration of the incident angle θ is Ts (θ), Ts (θ) is obtained by the following equation (12).

Ts (θ) = Is (θ) / Ir (θ) (12) When calculating a phase change in transmission, first, the phase characteristic Φ1 (θ) in the above-described first processing is obtained. And the second
And the phase characteristic Φ2 (θ) in the above processing are obtained.

These phase characteristics Φ1 (θ), Φ2 (θ)
Can be measured, for example, as follows.

First, the light source unit 19 described with reference to FIG. 21 is prepared as a light source, and the light receiving unit 21 described with reference to FIG. 21 is prepared as a light receiving unit. This light source unit 1
9 is disposed in front of the first reflection surface M1,
1 is arranged after the fourth reflection surface M4. This light source unit 1
9 from the optical characteristic measuring unit 30 of the present invention.
At a time as incident light L1. And the first
From the light intensity measured by the light receiving unit 21 in each of the processing and the second processing, and a known calculation theory specific to ellipsometry,
The phase characteristics Φ1 (θ) and Φ2 (θ) are calculated. Using these calculated Φ1 (θ) and Φ2 (θ), the phase change in transmission of the measured object 33 is obtained by Φs = Φ2 (θ) -Φ1 (θ) (13)

(D) In practicing the invention of the optical characteristic measuring unit 30 of the present invention, preferably, the third
The reflection surface M3 and the fourth reflection surface M4 are arranged for the N-shape, and the line segment AD corresponds to the N state.
It is preferable to further include a reflecting surface moving device 37 for selectively forming a state in which the arrangement is rotated by 180 degrees with respect to the rotation axis (this state is referred to as a non-N state).

In the case of an apparatus provided with such a reflecting surface moving device 37, by using the device as described below, for example, the reflectance (absolute reflectance) of the DUT 33 and / or the phase change in the reflection can be obtained. Can be measured while changing the incident angle. 4A to 4D are explanatory diagrams thereof.

First, a state where the object 33 is not inserted into a predetermined position by the object moving device 35 is formed. Of course, the third and fourth reflecting surfaces M
3, M4 is arranged for N-shape (FIG. 4 (A)).
Then, while appropriately rotating the first and fourth reflecting surfaces M1 and M4 by the reflecting surface rotating device 31, the intensity (for example, the light amount Ir (θ)) of the emitted light L2 is measured (FIG. 4).
(B)). This process is referred to as a first process.

Next, a state where the measured object 33 is inserted into a predetermined position by the object moving device 35 is formed. Of course, the third and fourth reflecting surfaces M3 and M3 are provided by the reflecting surface moving device 37.
M4 is arranged to be rotated from the N-shaped position by 180 degrees around the line segment AD (FIG. 4C). Then, while appropriately rotating the first and fourth reflecting surfaces M1 and M4 by the reflecting surface rotating device 31, the intensity of the emitted light L2 (for example, the light amount Is
(Θ)) (FIG. 4 (D)). This process is referred to as a second process.

However, any of the first processing and the second processing may be performed first.

When the first processing and the second processing are performed, respectively, the third and fourth reflecting surfaces M3 and M3 are obtained.
M4 is moved by the reflecting surface moving device 37 so as to be in the N state or the non-N state. However, in the present invention, since the configuration and arrangement of the third and fourth reflecting surfaces are devised as described above, even if M3 and M4 are moved in this manner, the optical system before and after M3 and M4 are moved. The optical path length at
Optical characteristics such as focal length and aberration do not change. That is, the optical properties are preserved.

Next, based on the emitted light intensity measured in each of the above-described first processing and second processing, the reflectance Rs (θ) of the measured object 33 in consideration of the incident angle θ is obtained. This Rs (θ) is obtained by the following formula: Rs (θ) = Is (θ) / Ir (θ) (14) The principle is the same as in the case of the transmittance measurement described above.

The phase change Φ (θ) in reflection is
The phase change in transmission can be obtained by a method according to the method for obtaining the phase change. That is, except for the fact that the phase characteristic Φ2 (θ) obtained in the second processing is the phase characteristic in reflection, the phase change in reflection can be obtained by the following equation (15). Φs = Φ1 (θ) −Φ2 (θ) (15).

(E) In the case of the optical characteristic measuring unit 30 of the preferred embodiment including the reflecting surface moving device 37, the reflectance of the object to be measured with respect to the reflectance of the reference object (that is, the reflectance of the reference object) is used as follows. Relative reflectance) and / or a phase change in the reflection of the measured object with respect to a phase change in the reflection of the reference object (hereinafter, referred to as “relative phase change in reflection”)
Can be measured. FIGS. 5A and 5B are explanatory diagrams thereof.

First, the third and fourth reflecting surfaces M3 and M4 are brought into a non-N-shaped state by the reflecting surface moving device 37. Of course,
The reference object 39 is inserted into the predetermined position between the second and third reflecting surfaces M2 and M3 (the position where the object 33 is inserted) by the object moving device 35 (FIG. 5A). Then, while appropriately rotating the first and fourth reflecting surfaces M1 and M4 by the reflecting surface rotating device 31, the intensity (for example, the light amount Ir (θ)) of the emitted light L2 is measured (FIG. 5A).
This process is referred to as a first process.

Next, the measured object 33 is replaced with the reference object 39.
5A, the intensity of the emitted light L2 (for example, the light amount Is
(Θ)) (FIG. 5 (B)). This process is referred to as a second process.

Next, based on the emitted light intensity measured in each of the first and second processes, the relative reflectance and / or the relative phase change of the measured object 33 with respect to the reference object 39 are measured. However, in this case, Ir (θ) and Φ1
(Θ) is for the reference object. Except for using these, the relative reflectance can be obtained by the above equation (14), and the relative phase change can be obtained by the above equation (15).

When a configuration is provided with a reflecting surface moving device, as shown in FIG. 6, only the fourth reflecting surface M4 is in the N state (see FIG. 6A). A reflecting surface moving device 37a for selectively changing to the non-N state (see FIG. 6B) is provided, and the third reflecting surface M3 is moved to a position corresponding to the case where the third reflecting surface M3 is set to the non-N state. And a fifth reflecting surface M5 corresponding to the reflecting surface described above.

In this case, since the third reflecting surface M3 does not need to be moved, the structure of the reflecting surface moving device 37a can be simplified. However, in this case, the third reflection surface M3 and the fifth reflection surface M5 are susceptible to individual differences. Therefore, when it is desired to further preserve optical characteristics, the fifth reflection surface M5 may be provided without providing the fifth reflection surface M5. A configuration in which the third and fourth reflecting surfaces M3 and M4 are moved (the configuration described with reference to FIG. 4) is more preferable.

(F) In the optical characteristic measuring unit of the present invention, when the light having a small beam diameter is used as the incident light, when the F-number of the incident light is large, or when the entire optical system is small, the optical path length is short. In such cases, the second and third
Instead of configuring each of the reflecting surfaces M2 and M3 of a spheroidal surface, an elliptical cylindrical surface having no curvature in a direction perpendicular to a plane including the N-shaped optical path, or a shape similar to the spheroidal surface Or a cylindrical surface having a shape similar to the spheroid. For example, when the beam diameter is small, the light reflected by the first reflecting surface M1 is incident somewhere on the line of the elliptical model in FIG. 2 even if the incident angle is changed. That is, the spread of light in the direction perpendicular to the plane of FIG. 2 is small. Therefore, the second and third reflecting surfaces M2, M
3 may be constituted by a spherical or cylindrical surface as described above,
An optical system equivalent to the case where M2 and M3 are constituted by spheroids can be realized. Nevertheless, the above spherical and cylindrical surfaces are
All of them are easier to manufacture than spheroids, so that, for example, the cost of the optical property measuring unit can be reduced.

(G) In practicing the invention of the optical characteristic measuring unit of the present invention, instead of the reflecting surface rotating device 31, as shown in FIG. Is a line segment A connecting the incident point A and the output point D.
Reflection surface rotation device 4 that rotates in conjunction with D as a rotation axis
1 (hereinafter, also referred to as a second reflection surface rotating device 41).

Using this second reflecting surface rotating device 41,
When the first reflecting surface M1 is rotated by an angle α (FIG. 7B) about the line segment AD as a rotation axis, the incident angle θ of light to the measured surface 33a can be expressed by the following equation (16). .

Θ = arccos {cosθocosα} (16) The reason why θ is given as described above will be described with reference to FIG. However, in FIG. 8, N is the measured surface 33a.
So is the vector of the light ray incident on the measured surface 33a when α = 0 (the initial state of the first reflecting surface M1),
S is a vector of a light ray incident on the surface to be measured 33a when the first reflection surface M1 is rotated by an angle α using the line segment AD as a rotation axis. It is assumed that all three vectors are unit vectors. Θo is the measured surface 33 at α = 0.
The angle of incidence on a. In FIG. 8, in order to simplify the calculation, the direction of the vector So is defined as the z-axis, and the y-axis is defined so that the plane on which the vector S moves is yz. At this time, the normal vector N is automatically in the xz plane.

The component of the vector N is given by the following equation (17), and the component of the vector So is given by the following equation (18)
It is as the formula.

N = (sin θo, 0, cos θo) (17) S = (0, sin α, cos α) (18) The incident angle θ is obtained by using the inner product of the above vectors as follows: 19) It can be expressed like the equation.

N · S = | N || So | cosθ (19) where | N || So | = cosθocosα, | N |
= 1 and | So | = 1, so these are substituted into the expression (19), and when the expression is modified, the above expression (16) is obtained.

If θo = 10 degrees, the first reflecting surface M1
By changing the rotation angle α in the range of 0 to 90 degrees, the incident angle θ can be arbitrarily changed in the range of 10 to 90 degrees.

The use of the second reflecting surface rotating device 41 makes it possible to design an optical characteristic measuring unit different from the case where the reflecting surface rotating device 31 is used. Therefore, the degree of freedom in designing the optical characteristic measuring unit is improved.

In the case of using the second reflecting surface rotating device 41, the first reflecting surface M2 is a spheroidal surface having the incident point A and the center O of the optical system as focal points. Even if the reflecting surface M1 is rotated, the first and second reflecting surfaces M
The reflected light passing through 1 and M2 always passes through the center O of the optical system. Of course, the optical path length from the point A to the center O of the optical system via the point B does not change even if the first reflection surface M1 is rotated. Also, in the case of the second reflecting surface rotating device 41, the fourth reflecting surface M4 can be rotated in conjunction with the rotation of the first reflecting surface M1. The direction and amount of rotation of the fourth reflecting surface M4 may be set such that the light L4 emitted from the fourth reflecting surface M4 is coaxial with the light incident on the first reflecting surface M1. it can.

Thus, the optical characteristics such as the optical path length, the focal length, and the aberration can be preserved even in the case of the configuration using the second reflecting surface rotating device 41.

(H) In the case of the optical characteristic measuring unit having the second reflecting surface rotating device 41, the first and fourth reflecting surfaces M1 and M4 are rotated by the reflecting surface rotating device 31.
The transmittance, phase change in transmission, reflectance of the object to be measured are the same as in the case of the optical property measurement unit including the reflecting surface rotation device 31 except that the optical property measurement unit is provided with , The phase change in reflection can be measured. Hereinafter, a brief description will be given.

FIGS. 7A and 7B are explanatory diagrams of a case where an optical characteristic measuring unit provided with the second reflecting surface rotating device 41 measures a transmittance and / or a phase change in transmission. The intensity of the outgoing light L2 is measured without inserting an object to be measured between the second and third reflecting surfaces M2 and M3 (FIG. 7A). With the measured object 33 inserted at a predetermined position between the second and third reflecting surfaces M2 and M3, the emitted light L2
Is measured (FIG. 7 (B)). The principle of obtaining the transmittance and / or the phase change in the transmission from the information obtained by these measurements is the same as that of the optical property measuring unit provided with the reflecting surface rotating device 31, so that the description is omitted.

FIGS. 9A and 9B are explanatory diagrams of a case where an optical reflectance measuring unit provided with the second reflecting surface rotating device 41 measures an absolute reflectance and / or a phase change in reflection. The intensity of the outgoing light L2 is measured without inserting the object to be measured between the second and third reflecting surfaces M2 and M3 (FIG. 9A). Second and third reflecting surfaces M2, M3
In a state where the DUT 33 is inserted at a predetermined position between
FIG. 9 shows the third and fourth reflecting surfaces centered on the AD line.
The output light L2 is rotated 180 degrees from the state of FIG.
Is measured (FIG. 9B). The principle of obtaining the absolute reflectance and / or the phase change in reflection from the information obtained by these measurements is the same as that of the optical property measuring unit provided with the reflecting surface rotating device 31, so that the description is omitted.

FIGS. 10A and 10B are explanatory diagrams of a case where an optical characteristic measuring unit provided with the second reflecting surface rotating device 41 measures a relative reflectance and / or a relative phase change.

The third and fourth reflecting surfaces M3 and M4 are
It is not a position forming a character shape, but a line segment AD
Is moved by a reflection surface rotating device 31 (see FIG. 1) to a position (non-N-shaped position) rotated by 180 degrees with respect to. Then, the reference object 39 is placed at a predetermined position (FIG. 1).
0 (A)). Then, the intensity of the emitted light L2 is measured in this state. Next, the measured object 33 is placed at a predetermined position instead of the reference object. Then, in this state, the intensity of the emitted light L2 is measured (FIG. 10B). The principle of obtaining the relative reflectivity and / or the relative phase change in reflection from the information obtained by these measurements is the same as in the case of the optical property measuring unit provided with the reflecting surface rotating device 31, and the description thereof is omitted.

(I) In the case of the optical characteristic measuring unit having the second reflecting surface rotating device 41, when the beam diameter of the incident light is small, when the F value of the incident light is large, or when the entire optical system is used. In the case where the optical path length is short due to the small distance, the second and third reflecting surfaces M2 and M3 may be constituted by a predetermined cylindrical surface described later instead of being constituted by a spheroidal surface. This will be described in detail with reference to FIG.

When the second reflecting surface rotating device 41 is used,
When the first reflecting surface M1 is rotated, the trajectory of the light incident point on the second reflecting surface M2 is, as shown by a halftone dot pattern in FIG. It will be along. Of course,
As shown in FIG. 11B, the spheroidal surface follows the portion having the least elliptical component. That is, FIG.
As shown in FIG. 3C, the light is applied along a surface having a spherical component. Therefore, when the beam system of the light beam entering M2 is small or the like, as shown in FIG. 11D, the second and third reflecting surfaces M2 and M
Even when each of the three is configured, the operation and effect of the present invention can be obtained.

[0094]

Embodiments of the present invention will be described below with reference to the drawings. However, the drawings used in the description are only schematically shown to the extent that the present invention can be understood. In the drawings used in the following description, the same components are denoted by the same reference numerals. In addition, redundant description of similar components may be omitted.

1. First Embodiment FIG. 12 is a perspective view illustrating an optical property measuring unit according to a first embodiment.

In this optical characteristic measuring unit, the substrate 51
Above, the first to fourth reflecting surfaces M1 to M4 are arranged such that the optical path passing through these reflecting surfaces is N-shaped.

Each of the first and fourth reflecting surfaces M1 and M4 is constituted by a plane mirror. Further, the second reflection surface M2
Is constituted by a part of the spheroidal surface having the focal point at the incident point A and the center O of the optical system. Further, the third reflecting surface M3 is constituted by a part of a spheroidal surface having the optical system center O and the emission point D as focal points.

Further, the second and third reflecting surfaces M2, M3
Each is fixed to the substrate 51. On the contrary,
Each of the first and fourth reflecting surfaces M1 and M4 is
Not fixed to 1.

The first reflecting surface M1 is connected to the first rotating shaft 53
Is connected to one end. This first rotating shaft 53 is
One through hole 51 a reaches the back surface of the substrate 51.
The other end of the first rotating shaft 53 is connected to a first pulley 55.

Further, the fourth reflecting surface M4 is connected to the second rotating shaft 5
7 is connected to one end. The second rotation shaft 57 reaches the back surface of the substrate 51 through the through hole 51b of the substrate 51. The other end of the second rotation shaft 57 is connected to a second pulley 59.

The optical characteristic measuring unit includes a motor 61 as a rotating means. A third pulley 63 and a fourth pulley 65 are connected to a shaft 61a of the motor 61. As the motor, for example, a stepping motor can be used.

The third pulley 63 and the first pulley 55 are connected by a belt 67. Fourth pulley 65
And the second pulley 59 are connected by a belt 69.

In the first embodiment, the rotating shaft 53,
57, each pulley 55, 59, 63, 65, and the motor 6
1 constitutes the reflection surface rotating device 31.

The optical characteristic measuring unit includes an object moving device 35. The object moving device 35 puts a measured object (including a reference object) into and out of a predetermined position according to the present invention. The object moving device 35 is constituted by an arbitrary moving mechanism.

In the case of the first embodiment, the motor 61
Is rotated, the rotation is transmitted to the first and fourth reflecting surfaces M1 and M4 by the respective pulleys and the rotation shaft. Therefore, in the case of this example, the first and fourth reflecting surfaces M1, M
4 can be rotated in the same direction and by the same angle.

If the spheroid forming the second reflecting surface M2 and the spheroid forming the third reflecting surface M3 have the same shape, the first reflecting surface M1 is rotated by φ. The rotation angle and the rotation direction of the fourth reflecting surface M4 corresponding to the above may be the same as those of the first reflecting surface M1. If the shapes of M2 and M3 are different, the fourth
It is necessary to determine the driving condition of the reflection surface M4.

In the case of the optical characteristic measuring unit of the embodiment shown in FIG. 12, each processing described with reference to FIGS. 3A and 3B is possible. Therefore, it is possible to measure the transmittance and / or the phase change in the transmission of the DUT.

2. Second Embodiment FIG. 13 is a perspective view illustrating an optical characteristic measuring unit according to a second embodiment.

In the first embodiment, the first and fourth reflecting surfaces M1 and M4 are finally connected to the common motor 61. On the other hand, in the second embodiment, the first and second reflecting surfaces M1 and M4 are connected to separate motors 71 and 73, respectively.

In the case of the second embodiment, the motor 7
1, 73 and the rotating shafts 53, 57, the reflecting surface rotating device 31
Is composed.

In the case of this example, since the motors 71 and 73 can be driven separately, the rotation direction and the rotation amount of the first and fourth reflection surfaces M1 and M4 can be arbitrarily controlled.

In this case, the motor 73 and the rotating shaft 57
The portion consisting of also serves as a reflection surface moving device 37 for moving the fourth reflection surface M4 by 180 degrees around the line segment AD.

In the first embodiment, the third reflecting surface M3 is fixed to the substrate 51, but in the second embodiment, the third reflecting surface M3 is fixed to the substrate 51. Not. Needless to say, the third reflecting surface M3 is configured to be able to rotate 180 degrees around the line segment AD by the reflecting surface moving device 37.

The reflecting surface moving device 37 for moving the third reflecting surface M3 is constituted by any suitable moving mechanism.

In the case of the optical characteristic measuring unit according to the second embodiment, since each processing described with reference to FIGS. 4A to 4D can be performed, the absolute reflectance and / or reflection of the object to be measured can be reduced. Phase change can be measured.

Further, in the case of the optical characteristic measuring unit according to the second embodiment, since the respective processes described with reference to FIGS. 5A and 5B can be performed, the relative reflectance of the object to be measured and / or The relative phase change in reflection can be measured.

Further, in the case of the optical characteristic measuring unit of the second embodiment, if the reflecting surface moving device 37 is not used, as in the first embodiment, the transmittance of the object and / or The phase change in transmission can be measured.

Therefore, according to the optical characteristic measuring unit of the second embodiment, a phase change in the absolute reflectance and / or reflection of the object, a relative phase change in the relative reflectance and / or reflection of the object, The transmittance and / or the phase change in transmission of the object can be measured.

3. Third Embodiment FIG. 14 is a view for explaining an example in which the optical property measurement unit of the present invention is applied to an ellipsometer.

The ellipsometer includes the optical characteristic measuring unit 30 according to the present invention, a light source unit 81, and a light receiving unit 83.

The light source section 81 can be composed of, for example, a light source (for example, a monochromator) 81a for outputting light of an arbitrary wavelength and a polarizer 81b. The light receiving section 83 can be composed of, for example, an analyzer 83a and a light receiving element 83b.

The light from the light source 81 is incident on the first reflection surface M1 as incident light L1. The light receiving section 83 is located on the AD line, at the subsequent stage of the fourth reflection surface M4.

In the case of the ellipsometer shown in FIG. 14, an ellipsometer having a structure in which the light source unit 81, the optical characteristic measuring unit 30, and the light receiving unit 83 are linearly arranged can be realized. Of course, an ellipsometer can be realized without using a gonio stage or the like.

[0124] 4. Fourth Embodiment FIG. 15 is a diagram illustrating an example in which the optical property measurement unit of the present invention is combined with a commercially available spectrophotometer 90.

The spectrophotometer 90 includes a light source unit 91 and a measuring unit 93. The measuring section 93 has a reference optical path and a sample optical path. The light source unit 91 outputs light alternately to the reference optical path and the sample optical path. These lights are referred to as reference light Lr and sample light Ls for explanation.

The optical characteristic measuring device 30 according to the present invention is arranged in the sample optical path. The light receiving section 95 receives the reference light Lr and the sample light Ls alternately.

According to this embodiment, a commercially available spectrophotometer and the optical characteristic measuring unit of the present invention can be used to measure the absolute reflectance and / or the phase change in reflection of an object to be measured.
The relative reflectance and / or relative phase change in reflection of the device under test, and the transmittance and / or phase change in transmission of the device under test can be measured. Moreover, in any of these measurements, the intended measurement can be performed without replacing or adjusting the optical system.

5. Fifth Embodiment FIG. 16 is a diagram illustrating an example in which the optical property measurement unit of the present invention is applied to an ellipsometer, and also illustrates an example in which a double beam method is applied.

In the apparatus of this embodiment, a reference light path 101 and a sample light path 103 are formed between the light source 81 and the light receiving section 83. Then, for each of the reference optical path 101 and the sample optical path 103,
The optical characteristic measuring unit 30 of the present invention is inserted.

The light emitted from the light source 81 is temporally distributed by the first chopper mirror 105. Then, the light beam travels along the reference light path 101 and the sample light path 103.

The second chopper mirror 1 is provided before the light receiving section 83.
07 is provided. This second chopper mirror 107
Reference light that has passed through the reference light path 101;
The sample light that has passed through the sample optical path 103 is selectively input to the light receiving unit 83.

According to the apparatus of this embodiment, an ellipsometer capable of performing photometry by the double beam method is realized. Therefore, it is possible to realize an ellipsometer having higher measurement accuracy than a conventional ellipsometer.

6. Sixth Embodiment In the optical characteristic measuring unit of the present invention, the second and third optical characteristic measuring units are used.
It has been described that the reflection surface is constituted by a spheroidal surface, a predetermined spherical surface, an elliptic cylindrical surface, or a cylindrical surface (hereinafter, these are referred to as spheroidal surfaces and the like). However, in the present invention, the case where a plane mirror or a spherical mirror is moved and used so as to correspond to a spheroid or the like is also included in the spheroid or the like referred to in the present invention. This will be described with reference to FIG.

In FIG. 17, the second reflecting surface M2 and the third reflecting surface M2
Are each configured by a plane mirror or a spherical mirror. Then, the first mirror or the spherical mirror M2 receives the light beam from the first reflecting surface M1 when the first reflecting surface M1 is rotated, and emits the received light to the center O of the optical system. And moves in synchronization with the rotation of the reflection surface M1. On the other hand, this plane mirror or spherical mirror M3
Moves in synchronization with the movement of the second reflecting surface M2, and
It is configured to be able to receive light rays from the second reflection surface M2 and to move the received light to a point D on the fourth reflection surface.

In the case of the sixth embodiment, each of the second and third reflecting surfaces M2 and M3 can be constituted by a plane mirror or a spherical mirror.
The second and third reflecting surfaces themselves can be made small and inexpensive.
However, in this case, a mechanism for driving a plane mirror or a spherical mirror is required so as to follow the light beam.

[0136]

As is apparent from the above description, according to the optical characteristic measuring unit of the present invention, the first to fourth reflecting surfaces having a predetermined arrangement and a predetermined structure for sequentially reflecting incident light, A reflecting surface rotating device for rotating the reflecting surface and the fourth reflecting surface, and an object moving device for moving an object to be measured between the second reflecting surface and the third reflecting surface. Therefore, the transmittance and / or the phase change of light in transmission can be measured while changing the incident angle without changing the optical system.

Further, according to the optical characteristic measuring unit of the preferred embodiment of the present invention, a predetermined reflecting surface moving device for moving the third and fourth reflecting surfaces is further provided. For this reason,
Without changing the optics, change the optical phase change in transmittance and / or transmission, the phase change of light in reflectivity and / or reflection, the relative reflectivity and / or any optical properties of the relative phase change while changing the angle of incidence. Can be measured.

Therefore, according to the optical characteristic measuring unit of the present invention, the transmittance, the reflectance, and the light transmission in the transmission and reflection can be changed without changing the optical characteristics of the optical system and the position of the light receiving portion while arbitrarily changing the incident angle. The phase change can be measured more easily than before.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an optical characteristic measurement unit according to the present invention.

FIG. 2 is a diagram illustrating the reason why the angle of incidence on an object to be measured can be changed by the optical property measuring unit of the present invention.

FIG. 3 is an explanatory diagram in a case where a transmittance and / or a phase change of light in transmission is measured using the optical property measurement unit of the present invention.

FIG. 4 is an explanatory diagram in the case of measuring the absolute reflectance and / or the phase change of light in reflection using the optical property measurement unit of the present invention.

FIG. 5 is an explanatory diagram of a case where a relative reflectance and / or a change in relative phase of light in reflection is measured using the optical property measurement unit of the present invention.

FIG. 6 is an explanatory view of a modified example of the optical characteristic measuring unit of the present invention.

FIG. 7 is an explanatory diagram of another modified example of the optical characteristic measuring unit of the present invention. Needless to say, it is an explanatory diagram in the case of measuring a transmittance and / or a phase change of light in transmission using an optical property measurement unit provided with a second reflecting surface rotating device 41.

FIG. 8 is a diagram illustrating the operation of the second reflecting surface rotation device 41.

FIG. 9 is an explanatory diagram in the case of measuring an absolute reflectance and / or a phase change of light in reflection using an optical property measurement unit provided with a second reflecting surface rotating device 41;

FIG. 10 is an explanatory diagram of a case where a relative reflectance and / or a change in relative phase of light in reflection is measured using an optical property measurement unit including a second reflecting surface rotating device 41.

FIG. 11 is an explanatory view of a modification of the second and third reflecting surfaces used in the present invention.

FIG. 12 is an explanatory diagram of the first embodiment.

FIG. 13 is an explanatory diagram of the second embodiment.

FIG. 14 is an explanatory diagram of the third embodiment.

FIG. 15 is an explanatory diagram of the fourth embodiment.

FIG. 16 is an explanatory diagram of the fifth embodiment.

FIG. 17 is an explanatory diagram of the sixth embodiment.

FIG. 18 is an explanatory diagram of a conventional transmittance measuring device.

FIG. 19 is an explanatory diagram of a conventional absolute reflectance measuring device.

FIG. 20 is an explanatory view of a conventional relative reflectance measuring device.

FIG. 21 is an explanatory diagram of a conventional ellipsometer.

[Explanation of symbols]

 M1: first reflecting surface M2: second reflecting surface M3: third reflecting surface M4: fourth reflecting surface M5: fifth reflecting surface A: incident point D: emission point O: optical system center 30: Optical property measurement unit 31: Reflection surface rotation device 33: DUT 33a: Measurement target surface 35: Object movement device 37, 37a: Reflection surface movement device 39: Reference object 41: Reflection surface rotation device (second reflection surface rotation) Apparatus) 51: Substrate 51a, 51b: Through hole 53: First rotating shaft 55: First pulley 57: Second rotating shaft 59: Second pulley 61, 71, 73: Rotating means (for example, motor) 61a: Shaft 63: Third pulley 65: fourth pulley 67, 69: belt 81: light source unit 81a: light source 81b: polarizer 83: light receiving unit 83a: analyzer 83b: light receiving element 90: spectrophotometer 91: light source unit 93: measuring unit 95 ： Light receiving part 10 1: Reference optical path 103: Sample optical path 105: First chopper mirror 107: Second chopper mirror

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 21/00-21/61 G01J 4/00-4/04 G01M 11/00 G01J 3/00-3 / 52

Claims (12)

(57) [Claims] A first reflecting surface for sequentially reflecting incident light; a reflecting surface rotating device for rotating the first reflecting surface and the fourth reflecting surface; And an object moving device that moves between the reflecting surface and the third reflecting surface. The optical path passing through the first to fourth reflecting surfaces becomes N-shaped through the first to fourth reflecting surfaces. And the incident light incident on the first reflection surface and the emission light exiting from the fourth reflection surface are arranged coaxially. Each of the reflection surfaces is a reflection surface arranged perpendicular to a plane including the N-shaped optical path, and an incident point of the incident light on the first reflection surface and emission of the incident light on the fourth reflection surface The intersection of the line connecting the points and the trajectory of the light beam traveling from the second reflecting surface to the third reflecting surface is defined as the center of the optical system. When defined, the second reflecting surface is constituted by a first spheroidal surface having a focal point at the center of the optical system and the incident point of the incident light on the first reflecting surface, 3. The reflecting surface of No. 3 is constituted by a second spheroidal surface having a focal point at the center of the optical system and the emission point of the outgoing light on the fourth reflecting surface. A device for rotating the first and fourth reflection surfaces in association with each other at respective arrangement positions of the first and fourth reflection surfaces about axes orthogonal to a plane including the N-shaped optical path, The object moving device is inserted between the second and third reflection surfaces so that the measured surface of the measured object is located at a position including the center of the optical system, and the object moving device is not inserted. Light as a device for selectively forming a non-inserted state Characteristic measuring unit. 2. The optical characteristic measuring unit according to claim 1, wherein each of the second and third reflecting surfaces is perpendicular to a plane including the N-shaped optical path instead of being constituted by the spheroidal surface. An ellipsoidal cylindrical surface having no curvature in various directions, or a spherical surface having a shape approximate to the spheroidal surface, or a cylindrical surface having a shape approximate to the spheroidal surface. Characteristic measurement unit. 3. A first to fourth reflecting surface for sequentially reflecting incident light; a reflecting surface rotating device for rotating the first and fourth reflecting surfaces; And an object moving device that moves between the reflecting surface and the third reflecting surface. The optical path passing through the first to fourth reflecting surfaces becomes N-shaped through the first to fourth reflecting surfaces. The incident light incident on the first reflecting surface and the outgoing light emitted from the fourth reflecting surface are arranged coaxially. The intersection of the line segment connecting the incident point on the reflecting surface and the emitting point on the fourth reflecting surface with the trajectory of the light beam traveling from the second reflecting surface to the third reflecting surface is defined as the center of the optical system. When the second reflecting surface is defined as a focal point, the second reflecting surface is focused on the center of the optical system and the incident point of the incident light on the first reflecting surface. Wherein the third reflecting surface is constituted by a second spheroidal surface having a focal point at the center of the optical system and the emission point of the outgoing light on the fourth reflecting surface. The reflection surface rotation device is a reflection surface rotation device that rotates the first and fourth reflection surfaces in conjunction with the line segment connecting the incident point and the emission point as a rotation axis, The object moving device is inserted between the second and third reflection surfaces such that the measured surface of the measured object is located at a position including the center of the optical system. An optical characteristic measuring unit, which is a device for selectively forming an inserted state. 4. The optical characteristic measuring unit according to claim 3, wherein each of the second and third reflecting surfaces is formed by a line segment connecting the incident point and the emitting point, instead of being configured by the spheroidal surface. An optical characteristic measuring unit comprising a cylindrical surface having no curvature in a direction along the same. 5. A transmission characteristic measuring device comprising the optical characteristic measuring unit according to claim 1. Description: 6. The optical characteristic measuring unit according to claim 1, wherein the non-inserted state is formed by the object moving device, and the first and fourth optical surfaces are rotated by the reflecting surface rotating device. A first process for measuring the intensity of the emitted light while rotating the reflecting surface, and forming the first and fourth reflecting surfaces by the reflecting surface rotating device in a state where the insertion state is formed by the object moving device. A second process of measuring the emitted light intensity while rotating, and a transmittance of light and / or a transmittance of the measured object based on the emitted light intensity measured in each of the first process and the second process. A transmission characteristic measuring method including a third process of measuring a phase change (however, the order of the first process and the second process is arbitrary). 7. The optical characteristic measuring unit according to claim 1, wherein the third reflecting surface and the fourth reflecting surface are arranged in an N-shape. State and a non-N arrangement in which the arrangement is rotated by 180 degrees with the line segment as a rotation axis with respect to the N state.
An optical characteristic measuring unit, further comprising a reflecting surface moving device for selectively forming a state. 8. The optical characteristic measuring unit according to claim 7, wherein instead of the reflection surface moving device, only the fourth reflection surface is selectively changed to the N state and the non-N state. An optical characteristic measurement unit comprising: a device; and a fifth reflection surface corresponding to the third reflection surface at a position corresponding to the case where the third reflection surface is set to the non-N state. 9. A reflection characteristic measuring device comprising the optical characteristic measuring unit according to claim 7. 10. An ellipsometer comprising the optical property measuring unit according to claim 7. Description: 11. The optical characteristic measuring unit according to claim 7, wherein the non-inserted state is formed by the object moving device, and the N state is formed by the reflecting surface moving device. A first process of measuring the intensity of the emitted light while rotating the first and fourth reflecting surfaces by a surface rotating device; and forming the insertion state by the object moving device; and
A second process of measuring the emitted light intensity while rotating the first and fourth reflecting surfaces by the reflecting surface rotating device in a state where the non-N state is formed by the reflecting surface moving device; A third process of measuring a reflectance of the object and / or a phase change of light in the reflection based on the intensity of the emitted light measured in each of the first process and the second process. Method (however, the order of the first processing and the second processing is arbitrary). 12. The optical property measurement unit according to claim 7, wherein the reference object is set in the inserted state by the object moving device, and the non-N is set by the reflecting surface moving device.
In a state where the state is formed, a first process of measuring the output light intensity while rotating the first and fourth reflection surfaces by the reflection surface rotating device, A second method of measuring the intensity of the emitted light while rotating the first and fourth reflecting surfaces by the reflecting surface rotating device in a state where the non-N state is formed by the reflecting surface moving device in the inserted state and the reflecting surface moving device. And a third process of measuring a reflectance of the object and / or a phase change of light in the reflection based on the output light intensity measured in each of the first process and the second process. Characteristic reflection characteristic measuring method (however, the order of the first processing and the second processing is arbitrary).