WO2021039900A1 - Sample measurement device and sample measurement method - Google Patents

Abstract

A sample measurement device having a light source 1, a light-receiving element 2 for receiving light emitted from the light source 1, and an optical element 3 which is positioned farther toward the light source 1 than the light-receiving element 2 and which selectively extracts a light component that is polarized in a specific direction from among incident light, wherein the sample measurement device includes at least one specific-polarization element 5 from among (1) and (2) below. (1) Both of a specific-polarization element 5 which is positioned farther toward the light source 1 than a sample 4 to be measured and which transmits or reflects light emitted from the light source 1, and a specific-polarization element 5 which is positioned farther toward the light-receiving element 2 than the sample 4 to be measured and which transmits or reflects light that is transmitted or reflected by the sample 4 to be measured. (2) A specific-polarization element 5 which is positioned farther toward the light source 1 than the sample 4 to be measured and farther toward the light-receiving element 2 than the sample 4 to be measured, and which transmits or reflects light emitted from the light source 1 and transmits or reflects light that is reflected from the sample 4 to be measured.

Description

Sample measuring device and sample measuring method

The present invention relates to an apparatus and a sample measuring method for measuring the physical characteristics of a sample by detecting the traveling direction distribution of incident light in the sample to be measured.

Confocal detection method, light lever method, dark field illumination method, interference, polarization space conversion element, and other methods are known as methods for detecting slight differences in the optical path.

1. 1. Spatial transmittance conversion element This is a method of detecting the difference in the optical path by providing a conversion element having a spatial distribution of transmittance in the detection optical system. Annulus illumination and aperture control of a microscope are methods that selectively shield high-frequency components and low-frequency components of the Fourier plane in the imaging system, and change the optical path (optical path shift) due to the spatial periodic structure of the sample. This is a detection method. In addition, dark-field illumination illuminates the measurement target from outside the field of view, and only when there is an object that induces an optical path shift such as light scattering, it enters the field of view and is detected. The confocal optical system is often used in microscopes, and a space conversion element such as a pinhole is placed at a position where light emitted from a point light source (a laser beam can also be classified as a point light source) is refocused. Since light rays whose optical paths are deviated due to multiple scattering or refraction cannot pass through pinholes, the change can be measured as an optical path shift. Schlieren detection is also interpreted as the same as confocal in principle.

2. 2. This method is used for microscopes with a light lever cantilever probe. The cantilever is irradiated with a laser beam, and the angle of the reflected light (displacement in the distal direction) is detected. By setting the detection position far from the cantilever, a slight deflection of the cantilever is amplified as an optical path shift of the beam. A split detector or image sensor is used for detection.

3. 3. Interference optical system In hologram measurement, the optical path shift can be visualized by using the interference of two luminous fluxes. A slight displacement of the detected light with respect to the reference light is reflected in the interference fringes, and the optical path shift amount can be obtained by analyzing the fringes.

4. Polarized space conversion element The polarized space conversion element is, for example, a polarized space conversion element (polarization space filter) having a spatial distribution as described in Patent Document 1. The polarization characteristics in this conversion element are not constant, and the conversion element has different characteristics depending on the location. Conventionally, linearly polarized lighters, phasers, birefringent phasers and the like having high uniformity have been generally used, but on the contrary, they are polarizing elements in which the polarization characteristics are spatially distributed.

JP-A-2018-87885

Each of the above optical detection methods has its own merits, but there is room for further improvement in order to provide a popular type detection device that makes the detection more accurate and the detection device itself is not too expensive. ..

The present invention provides a measuring device and a measuring method capable of detecting inclination, waviness, minute steps, scratches, etc. of a reflecting surface by performing spatial polarization filtering on both incident light and reflected light. Is the purpose.

The technology for spatially controlling the polarization distribution of the beam can be implemented in optical equipment using the above-mentioned polarization space conversion element. In particular, a beam called an axisymmetric beam, which is polarized and whose phase is axisymmetric with respect to the main ray of the beam, pays attention to the peculiar property of the focusing point, and controls the orbital angle momentum and the focal electric field distribution. And so on, it has been developed as a method for generating a focal shape required for focus engineering as in Non-Patent Document 1. On the other hand, the polarizing element used as an optical element for focus control can also be used as a detection conversion element that selectively transmits a specific polarization distribution. For example, when observing the light emitted from a point light source on the pupil surface of a condensing lens, the intensity, phase, and polarization of the light may be distributed depending on the radiation direction. For example, it is used for detecting three-dimensional molecular orientation. (Non-Patent Document 2). As described above, in the field of optical measurement, it is possible to add a new function to the optical system by inserting a polarizing space conversion element in both the incident light and the reflected light on the sample.

The sample measuring device according to the present invention that has solved the above problems is
[1] A light source, a light receiving element that receives light emitted from the light source, and optics that are arranged on the light source side of the light receiving element and selectively extract light of a polarization component in a specific direction from the incident light. It is a sample measuring device having an element, and further includes at least one specific polarizing element of the following (1) and (2).
(1) A specific polarizing element that is arranged on the light source side of the measurement target sample and transmits or reflects light emitted from the light source, and a measurement target that is arranged on the light receiving element side of the measurement target sample. Both specific polarizing elements that transmit or reflect light that has passed or reflected the sample.
(2) It is arranged on the light source side of the measurement target sample and on the light receiving element side of the measurement target sample, transmits or reflects the light emitted from the light source, and reflects from the measurement target sample. A specific polarizing element that transmits or reflects the emitted light.
[Specific polarizing element]
A transmissive or reflective polarizing element having an in-plane x-axis direction and a y-axis direction orthogonal to the x-axis direction, in which the Jones matrix differs depending on the in-plane position.

In the present invention, a relatively simple optical system is obtained by selectively extracting light of a polarizing component in a specific direction from light transmitted through a polarizing element whose Jones matrix differs depending on the position in the plane and detecting the amount of light. Can be used to detect the inclination, waviness, minute steps, scratches, etc. of the reflective surface of the sample. In addition, the present invention can be more preferably carried out by using a more specific sample measuring device or a specific measuring method as listed below.

[2] The sample according to [1], which has both of the specific polarizing elements specified by (1) of the above [1], and both of the specific polarizing elements are arranged on one side of the sample to be measured. measuring device.

[3] When the light incident on the region Rin in the xy plane of the specific polarizing element is incident on the region Rout at the position of the central axis of the specific polarizing element with respect to the region Rin, the region Rout is transmitted. The sample measuring device according to [1] or [2], wherein the Jones vector of the light obtained is the same as the Jones vector of the light incident on the region Rin.

[4] The specific polarizing element has M regions (R1 to RM) in the xy plane, and is located at a position of the region Ri and a central axis target of the specific polarizing element with respect to the region Ri. The sample measuring device according to any one of [1] to [3], which has a region Rj and a region Rk adjacent to the region Rj and satisfies the following conditions A and B.
[Condition A]
When the light whose Jones vector is Jxy is incident on the region Ri and the transmitted light is further incident on the region Rj, the Jones vector of the light transmitted through the region Rj is the same as that of Jxy.
[Condition B]
The Jones matrix of region Rk is different from the Jones matrix of region Rj. However, the above i, j, k, and M are natural numbers, respectively.

[5] In the specific polarizing element, the magnitude of the angle α formed by the x-axis direction and the optical axis direction at a position separated by a distance r in the direction forming an angle θ degree with respect to the x-axis direction from the center is determined. The sample measuring apparatus according to any one of [1] to [4], which is increased or decreased as θ increases.

[6] The sample measuring device according to any one of [1] to [5], wherein the specific polarizing element has a Jones matrix different depending on the position in the radial direction.

[7] The sample measuring device according to any one of [4] to [6], wherein the magnitude of the angle α is (θ / 2) · n. However, n is an arbitrary constant.

[8] The sample measuring device according to [7], wherein n is 1.0 or less.

[9] The sample measuring device according to any one of [4] to [8], wherein the magnitude of the angle α is (θ / 2) · n. However, n is an integer.

[10] The sample measuring device according to any one of [4] to [9], wherein the magnitude of the angle α gradually increases or decreases as θ increases.

[11] When the angle θ is within a predetermined range, the α is constant, and the magnitude of the angle α increases or decreases stepwise as θ increases. [4] to [9] The sample measuring device according to item 1.

[12] The sample measuring device according to any one of [1] to [11], wherein an objective lens is arranged between the specific polarizing element and the sample to be measured.

[13] The light receiving element is composed of a first light receiving element and a second light receiving element, the optical element is a polarizing beam splitter, and the light reflected by the polarizing beam splitter is transferred by the first light receiving element. The sample measuring apparatus according to any one of [1] to [12], which receives light and receives light transmitted by the polarizing beam splitter by a second light receiving element.

[14] The specific polarizing element imparts a phase difference that is an integral multiple of a quarter wavelength between a polarization component parallel to the optical axis and a polarization component perpendicular to the optical axis [1]. The sample measuring apparatus according to any one of [13].

[15] The sample measuring device according to any one of [1] to [14], wherein the light receiving surface of the light receiving element is a Fourier surface of the sample to be measured.

[16] A light source, a light receiving element that receives light emitted from the light source, and optics that are arranged on the light source side of the light receiving element and selectively extract light of a polarization component in a specific direction from the incident light. A step of preparing an element and a sample measuring device including at least one of the following (1) and (2) specific polarizing elements, and
The step of emitting light from the light source and
The step of detecting the light passing through the sample to be measured by the light receiving element, and
Measurement method having.
(1) A specific polarizing element that is arranged on the light source side of the measurement target sample and transmits or reflects light emitted from the light source, and a measurement target that is arranged on the light receiving element side of the measurement target sample. Both specific polarizing elements that transmit or reflect light transmitted or reflected by the sample.
(2) It is arranged on the light source side of the measurement target sample and on the light receiving element side of the measurement target sample, transmits or reflects the light emitted from the light source, and reflects from the measurement target sample. A specific polarizing element that transmits or reflects the emitted light.
[Specific polarizing element]
A transmissive or reflective polarizing element having an in-plane x-axis direction and a y-axis direction orthogonal to the x-axis direction, in which the Jones matrix differs depending on the in-plane position.

[17] The measurement according to [16], wherein the specific polarizing element is divided into a plurality of regions in a plane, some of the plurality of regions are optical rotations, and the other plurality of regions are not optical rotations. Method.

[18] The specific polarizing element is a polarizing element in which the direction of the optical axis differs depending on the position in the plane, and x at a position separated by a distance r from the center in a direction forming an angle θ degree with respect to the x-axis direction. The measuring method according to [16] or [17], wherein the magnitude of the angle α formed by the axial direction and the optical axial direction increases or decreases as θ increases.

[19] In the sample measuring device,
(A) The light receiving element is composed of a first light receiving element and a second light receiving element, and the optical element is a polarizing beam splitter.
(B) The light reflected by the polarization beam splitter is received by the first light receiving element, and the light transmitted by the polarization beam splitter is received by the second light receiving element.
Any of [16] to [18] further comprising a step of calculating the ratio or difference between the light intensity detected by the first light receiving element and the light intensity detected by the second light receiving element. The measurement method described in item 1.

[20] When the light incident on the region Rin of the specific polarizing element is incident on the region Rout located at the position of the central axis of the specific polarizing element with respect to the region Rin, Jones of the light transmitted through the region Rout. The measuring method according to any one of [16] to [19], wherein the vector is the same as the Jones vector of light incident on the region Rin.

[21] The specific polarizing element has M regions (R1 to RM) in the xy plane, and is located at a position of the region Ri and a central axis target of the specific polarizing element with respect to the region Ri. The measuring method according to any one of [16] to [20], which has a region Rj and a region Rk adjacent to the region Rj and satisfies the following conditions A and B.
[Condition A]
When the light whose Jones vector is Jxy is incident on the region Ri and the transmitted light is further incident on the region Rj, the Jones vector of the light transmitted through the region Rj is the same as that of Jxy.
[Condition B]
The Jones matrix of region Rk is different from the Jones matrix of region Rj. However, i, j, k, and M are natural numbers, respectively.

In the present invention, it is relatively simple to detect the amount of light by selectively extracting the light of the polarization component in a specific direction from the light transmitted or reflected by the polarizing element having a different Jones matrix depending on the position in the plane. The optical system can be used to detect the inclination, waviness, minute steps and scratches of the reflecting surface of the sample.

(A) is a diagram showing the optical system of the sample measuring device according to the first embodiment of the present invention, and (b) is a diagram for explaining the reflection of light in the vicinity of the sample. It is a figure which shows the optical system of the sample measuring apparatus which concerns on Embodiment 2 of this invention. (A) is a diagram showing a specific polarizing element of the sample measuring device according to the second embodiment of the present invention, and (b) is an incident light when the specific polarizing element is viewed from the optical axis direction and from a sample. It is a figure which shows the position of the return light. It is a figure which shows the intensity of the return light from a sample in the specific polarization element of the sample measuring apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the intensity of the return light from a sample in the specific polarization element of the sample measuring apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the intensity of the return light from a sample in the specific polarization element of the sample measuring apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the intensity of the return light from a sample in the specific polarization element of the sample measuring apparatus which concerns on Embodiment 2 of this invention. (A) and (b) are graphs showing the relationship between the tilt angle of a sample and the intensity of return light in the sample measuring device according to the second embodiment of the present invention. Both (a) and (b) are graphs showing the Ir intensity when the amount of R / r is taken on the horizontal axis. It is a figure which shows the optical system of the sample measuring apparatus which concerns on Embodiment 3 of this invention. It is a figure which shows the deformation optical system of the sample measuring apparatus which concerns on Embodiments 1 to 3 of this invention. It is a figure which shows the optical system of the sample measuring apparatus which concerns on Embodiment 4 of this invention. It is a figure which shows the optical system of the sample measuring apparatus which concerns on Embodiment 4 of this invention. It is a figure which shows the optical system of the sample measuring apparatus which concerns on other embodiment.

Hereinafter, the present invention will be described in more detail based on the embodiments, but the present invention is not limited by the following embodiments as well as the present invention, and appropriate modifications are made to the extent that it can be adapted to the purpose of the above and the following. Of course, it is also possible to carry out the above, and all of them are included in the technical scope of the present invention.

The sample measuring device of the present invention includes a light source, a light receiving element that receives light emitted from the light source, and light of a polarizing component in a specific direction among incident light that is arranged on the light source side of the light receiving element. It is a sample measuring device having an optical element for selectively taking out, and further includes at least one specific polarizing element of the following (1) and (2).

(1) A specific polarizing element that is arranged on the light source side of the measurement target sample and receives light emitted from the light source, and a measurement target sample that is arranged on the light receiving element side of the measurement target sample. Both specific polarizing elements that receive transmitted or reflected light.
(2) It is arranged on the light source side of the measurement target sample and on the light receiving element side of the measurement target sample, receives the light emitted from the light source, and is reflected from the measurement target sample. A specific polarizing element that receives light.

In the present invention, the specific polarizing element is a transmission type or reflection type polarizing element having an in-plane x-axis direction and a y-axis direction orthogonal to the x-axis direction, and the Jones matrix differs depending on the in-plane position.

The measurement method according to the present invention that has solved the above problems is that a light source, a light receiving element that receives light emitted from the light source, and a light receiving element that is arranged closer to the light source side than the light receiving element and can be specified among incident light. A step of preparing an optical element that selectively extracts light of a polarization component in a direction, a sample measuring device including at least one of the above-mentioned (1) and (2) specific polarization elements, and a step of emitting light from the light source. It also has a step of detecting the light passing through the sample to be measured by the light receiving element.

In the sample measuring apparatus of the present invention and the measuring method of the present invention, (1) the light transmitted through the sample or (2) the light transmitted through the sample is the surface inclination, waviness, and waviness existing in the sample. In a place affected by a minute step or a scratch, the traveling direction of light changes according to the degree of the influence. The light whose traveling direction has changed is incident on the specific polarizing element. Since the specific polarizing element has a different Jones matrix depending on the position in the plane as described above, the light transmitted through the specific polarizing element has a different polarization state depending on the difference in the Jones matrix at the transmission point. .. Therefore, by detecting the polarization state of the light transmitted through the specific polarizing element, it is possible to specify at which position of the specific polarizing element the transmitted light is the light transmitted. Therefore, the specific polarizing element needs to know how the Jones matrix differs depending on the position. In order to detect the polarization state of the light transmitted through the specific polarizing element, the intensity of the light is finally measured by the light receiving element through the optical element that selectively extracts the light of the polarization component in the specific direction. Hereinafter, Embodiments 1 to 4 also serve as description of both the sample measuring device in the present invention and the measuring method of the present invention.

(Embodiment 1)
Hereinafter, the sample measuring device according to the first embodiment of the present invention and the measuring method using the device will be described with reference to FIG. FIG. 1A is a diagram showing an optical system of the sample measuring device according to the first embodiment of the present invention, and FIG. 1B is a diagram illustrating reflection of light in the vicinity of the sample. The sample measuring device according to the first embodiment is arranged on the light source 1, the light receiving element 2 that receives the light emitted from the light source 1, and the light source 1 side of the light receiving element 2, and is arranged in a specific direction among the incident light. It is a sample measuring apparatus having an optical element (polarizing beam splitter 3) for selectively extracting light of a polarizing component, and further includes a specific polarizing element described in (2) below. In the present invention, when the term "optical element B side of optical element A" is generally used, it is not only "a place closer to optical element B than optical element A" which is a mere spatial arrangement place, but also "a place closer to optical element B than optical element A". It also includes the meaning of "a place near the optical element B".

(2) It is arranged on the light source 1 side of the measurement target sample 4 and on the light receiving element 2 side of the measurement target sample 4, transmits the light emitted from the light source 1, and is from the measurement target sample 4. A specific polarizing element 5 that transmits the reflected light. That is, the light source 1, the light receiving element 2, and the specific polarizing element 5 are all present on one surface (reflection surface) side of the sample 4 to be measured.

Explaining by tracing the propagation path of the light emitted from the light source 1 in order, the light is first linearly polarized light that vibrates only in the y-axis direction by the linear polarizing plate 6. The light transmitted through the specific polarizing element 5 in the linearly polarized state is collected by the objective lens 7 and reflected on the surface of the sample 4 to be measured. The return light reflected from the sample 4 to be measured passes through the specific polarizing element 5 again. Here, the return light reflected from the measurement target sample 4 includes 0th-order reflected light, +1-order reflected light, or -1st-order reflected light mirror-reflected on the flat surface of the measurement target sample 4. The +1st-order reflected light, the 0th-order reflected light, and the -1st-order reflected light pass through the compartments 5a, 5b, and 5c of the specific polarizing element 5, respectively. The Jones matrices of compartments 5a, 5b, and 5c are different, and in the example of FIG. 1A, the + 1st-order reflected light is linearly polarized light that is rotated 90 degrees by the compartment 5a and vibrates only in the x-axis direction. The 0th-order reflected light is transmitted as linearly polarized light that continues to vibrate only in the y-axis direction without being subjected to the optical rotation action by the compartment 5b, and the -1st-order reflected light is rotated 45 degrees by the compartment 5c and is rotated in the x-axis direction and the y-axis direction. It becomes linearly polarized light having both vibration components and passes through the specific polarizing element 5.

When the light transmitted through the specific polarizing element 5 is incident on the polarizing beam splitter 3, the polarization component in the y-axis direction travels straight and is incident on the light receiving element 2T. Since there is no vibration in the y-axis direction for the + 1st-order reflected light, it does not reach the light receiving element 2T and the intensity is not observed. Since the 0th-order reflected light oscillates in the y-axis direction, it reaches the light receiving element 2T and is detected as strong light. Regarding the -1st-order reflected light, only the vibration component in the y-axis direction reaches the light receiving element 2T, and it is detected that the light is not as strong as the 0th-order reflected light.
The light can be detected only by using the light receiving element 2T, but it can also be detected by the component of light that is reflected by the polarizing beam splitter 3 and reaches the light receiving element 2R.

As described above, if the sample has a structure that induces a directional shift of the reflected light, such as an inclination or a minute step, the reflected light deviates from the assumed optical path and causes an optical path shift. As a result, as a result of passing through different parts of the specific polarizing element 5, the polarization direction of the return light from the sample is modulated. Therefore, the deviation of the optical path is converted into a change in polarization, and the reflected light is converted into the specific polarizing element 5 by detecting the light intensity of the portion where the deviation of the optical path is induced by detecting it through, for example, a polarization beam splitter 3. It is possible to identify which part of the throat (compartment 5a, compartment 5b, compartment 5c) has passed.

In the first embodiment, the polarization beam splitter 3 is used, but the present invention is not limited to this, and if an optical element that selectively extracts the light of the polarization component in a specific direction from the incident light is used, the reflection of the portion that induces the deviation of the optical path is used. Only light can be selectively detected. When the polarizing beam splitter 3 is used, the ratio or difference between the intensity received by the light receiving element 2T and the intensity received by the light receiving element 2R is obtained to obtain, for example, a portion having low reflectance in the sample 4 to be measured. It is also possible to cancel the decrease in the intensity received by the light receiving element 2T and the intensity received by the light receiving element 2R, and it is possible to perform detection with less error.

Although the first embodiment has been described using an optical system that detects the reflected light from the sample, it is also possible to measure the presence of foreign matter and air bubbles inside the sample by using the transmitted light of the sample. In this case, the specific polarizing element described by the following (1) is used.

(1) A specific polarizing element that is arranged on the light source side of the measurement target sample and transmits light emitted from the light source, and a measurement target sample that is arranged on the light receiving element side of the measurement target sample. Both specific polarizing elements that transmit transmitted light.

The specific polarizing element 5 preferably further has the following features. That is, the specific polarizing element 5 has M regions (R1 to RM) in the xy plane (not shown), and the specific polarization with respect to the region Ri (section 5d in FIG. 1) and this region Ri. It has a region Rj (compartment 5b) at a position targeted by the central axis (5ax) of the element 5 and a region Rk ( compartment 5a or 5c) adjacent to this region Rj, and has the following conditions A and B. Meet. However, i, j, k, and M are natural numbers, respectively.
[Condition A]
When the light whose Jones vector is Jxy is incident on the region Ri (section 5d) and the transmitted light is further incident on the region Rj (section 5b), the Jones vector of the light transmitted through the region Rj (section 5b) is Same as Jxy.
[Condition B]
The Jones matrix in region Rk ( partition 5a or 5c) is different from the Jones matrix in region Rj (partition 5b).

By satisfying the above condition A, when the incident light transmitted through the compartment 5d is specularly reflected in the sample 4 to be measured and re-entered into the compartment 5b, the polarization state of the light becomes the same as before the light was incident on the specific polarizing element 5. .. As a result, in the example of FIG. 1, the 0th-order light travels straight through the polarizing beam splitter 3 and is incident on the light receiving element 2T. The same applies when the sample 4 to be measured is a transparent material.

On the other hand, as in the above condition B, the Jones matrix of the region Rk ( section 5a or 5c) is different from the Jones matrix of the region Rj (section 5b), so that the ± primary light transmitted through the compartment 5a or 5c is Since the ratio of the x-direction vibration component and the y-direction vibration component of the light is different from that of the 0th-order light, a predetermined amount is incident on the light receiving element 2R as shown in FIG. This makes it possible to distinguish between the difference in the reflection angle of light on the surface of the sample 4 to be measured and the direction of the light transmitted through the sample 4 to be measured.

In condition B, only a part of the region Rk may form a Jones matrix different from the region Rj, but if all of the region Rk constitutes a Jones matrix different from the region Rj, the light is reflected by the mirror surface. On the other hand, the reflected light shift in any direction can be detected. It is more preferable that the region Rj and all the regions Rk adjacent to the region Rj form a Jones matrix different from each other.

By configuring the M regions (R1 to RM) with a large number of regions that are more finely divided, even a slight difference in the reflection direction of the reflected light can be detected. That is, although the number of Ms can be set as many as possible without an upper limit, the Jones matrix in each region changes continuously in the xy plane of the specific polarizing element 5, and individual regions cannot be defined. The case can be explained as follows.

That is, the light incident on the region Rin (not shown) in the xy plane of the specific polarizing element 5 is directed to the region Rout (not shown) at the position targeted by the central axis (5ax) of the specific polarizing element with respect to the region Rin. The Jones vector of the light transmitted through the region Rout when incident on the region Rin is the same as the Jones vector of the light incident on the region Rin. Such a specific polarizing element 5 can be manufactured, for example, by forming a predetermined light intensity distribution in a photochromic organic material that causes a change in the refractive index according to the intensity of incident light.

(Embodiment 2)
Hereinafter, the sample measuring apparatus according to the second embodiment of the present invention will be described with reference to FIGS. 2 to 8. FIG. 2 is a diagram showing an optical system of the sample measuring device according to the second embodiment of the present invention. The sample measuring device according to the second embodiment of the present invention is arranged on the light source 1, the light receiving element 2 that receives the light flux emitted from the light source 1, and the light source 1 side of the light receiving element 2, and is of the incident light. It is a sample measuring apparatus having an optical element (polarization beam splitter 3) that selectively extracts light of a polarization component in a specific direction, and further includes a specific polarization element described in (2) below.

(2) It is arranged on the light source 1 side of the measurement target sample 4 and on the light receiving element 2 side of the measurement target sample 4, transmits the bundled light emitted from the light source 1, and is the measurement target sample 4. A specific polarizing element 5 that transmits a light beam reflected from the light source. That is, the light source 1, the light receiving element 2, and the specific polarizing element 5 are all present on one surface (reflection surface) side of the sample 4 to be measured.

Explaining by tracing the propagation path of the luminous flux emitted from the light source 1 in order, the luminous flux is first linearly polarized light that vibrates only in the y-axis direction by the linear polarizing plate 6. The light flux transmitted through the specific polarizing element 5 in the state of linearly polarized light is focused by the objective lens 7 and reflected on the surface of the sample 4 to be measured. The return light reflected from the sample 4 to be measured passes through the specific polarizing element 5 again. Here, the return light reflected from the sample 4 to be measured includes the reflected light at various angles as described in the first embodiment. Each reflected light passes through another section of the specific polarizing element 5. The Jones matrix for each compartment is different.

The light transmitted through the specific polarizing element 5 is incident on the polarizing beam splitter 3, so that the polarization component in the y-axis direction travels straight and is incident on the light receiving element 2T or the light receiving element 2R. As already described in the first embodiment, the light can be detected by using only the light receiving element 2T, but it is detected by the component of the light that is reflected by the polarizing beam splitter 3 and reaches the light receiving element 2R. It is also possible.

FIG. 3A is a perspective view showing a specific polarizing element 5 of the sample measuring device according to the second embodiment of the present invention, and FIG. 3B is an incident view of the specific polarizing element 5 when viewed from the optical axis direction. It is a figure which shows the position of the light flux, and the position of the light flux of the return light from a sample 4.

As shown in FIG. 3A, the specific polarizing element 5 has compartments (for example, compartments 5d, 5e, 5f) divided by lines in the radial direction passing through the center, and the optical axis direction in each compartment is thick. Indicated by arrows, each compartment is, for example, a λ / 2 plate. As shown in FIG. 3A, the optical axis direction changes by a certain angle when the specific polarizing element 5 is moved by one section in the circumferential direction, and the optical axis direction changes by 90 degrees when the specific polarizing element 5 is rotated halfway. The optical axis direction is configured to change by 180 degrees when the polarizing element 5 goes around once. In the example of FIG. 3A, the section of the specific polarizing element 5 is divided into 16 equal parts all around, but it may be divided into any number of equal parts.

FIG. 3B is a diagram showing the position of the luminous flux of the incident light and the position of the luminous flux of the return light from the sample 4 when the specific polarizing element 5 is viewed from the optical axis direction. The number of compartments is larger than that of the example (16 compartments) in FIG. 3A, and there are 36 compartments, but the optic axis may change steplessly.

As shown in FIG. 3B, in the xy coordinate system in which the radius of the incident beam is r and the center of the incident beam is the origin O, and the coordinate system O'in the center of the return light beam is the xy'coordinate system. Represent. Let R be the amount of beam shift (distance between the center O of the incident beam and the center O'of the return light beam), and the shift direction of the beam, that is, the center O of the return light seen from the center O of the incident beam. Let Θ be the rotation angle of'. The optical axis of the specific polarizing element 5 is the same as the thick arrow shown in FIG. 3 (a), and the optical axis is gradually twisted as the specific polarizing element 5 changes in the circumferential direction. It shows a structure that twists by an angle that is an integral multiple of 180 degrees in the circumference (hereinafter, may be referred to as "rotational twist symmetry"). The specific polarizing element 5 may be used by being rotated in the θ direction. In FIGS. 3A and 3B, the function is to generate radial polarized light from light incident on horizontally polarized light.

As shown in FIG. 3 (b), when focusing on the light beam incident on the incident beam through the point I (r, θ) in the incident beam, the return light after reflection passes through the point E (however, the former r in parentheses is It indicates the distance from the origin O, and the latter θ indicates the angle formed with the x-axis). The point E is (x, X) in the xy coordinate system. Similarly, the former x in parentheses indicates the distance from the origin O, and the latter X indicates the angle formed with the x-axis. At this time, points I and E are defined as equations (1) and (2), respectively.

θ'and r'are described as in equations (3) and (4).

At this time, the direction of the optical axis of the specific polarizing element 5 is θ / 2 at the point I and X / 2 at the point E. When the change in the polarization state of light at this time is described in Jones notation, it becomes as shown in equation (5).

However, Ein and Eout represent the polarization of the incident light and the emitted light to the specific polarizing element 5, and M (θ) indicates the action of the λ / 2 plate rotated by θ in the azimuth direction. Further, S represents the action due to the reflection of the sample 4 to be measured, and the relationship of the equation (6) generally holds.

In equation (6), r0 represents the synergistic average of the reflectances of horizontally polarized light and vertically polarized light, and tanχ (rx / ry) is the ratio of the reflectances of the horizontally polarized light component and the vertically polarized light component (| rs | / | rp |. rs is the reflectance of s-polarized light, rp is the reflectance of p-polarized light), and Δ represents the phase difference that occurs between horizontally polarized light and vertically polarized light. These parameters have a large effect on the Jones vector when the incident angle is large, but as will be described later, in beam shift measurement, low NA applications with a small incident angle are suitable for obtaining high sensitivity. Can be thought of as the following equation (7).

From equation (5), it can be seen that the change in polarized light occurs when a light beam passing through an arbitrary point in the incident beam becomes return light. In FIG. 2, the same polarization component as the incident polarized light is separated and detected on the light receiving element 2R side, and the orthogonal component is separated and detected on the light receiving element 2T side via the polarizing beam splitter 3. Therefore, if R = 0 from the equation (1), X = Since π + θ and Ein and Eout have the same polarization direction, all the return light is detected on the light receiving element 2R side. On the other hand, if R ≠ 0, this relationship may not be established, so that the amount of light detected as the light receiving intensity IT of the light receiving element 2T increases, and instead, the light receiving intensity IR of the light receiving element 2T decreases. When a beam shift occurs in the horizontal direction, when the ratio of the beam shift distance R divided by the beam diameter r (R / r) = 0, when R / r = 0.5, and when R / r = 1, FIGS. 4 to 7 show the results of expressing the light intensity IR detected on the light receiving element 2R side by the light intensity distribution on the specific polarizing element 5 when R / r = 8. It can be seen that as the R / r increases, the intensity distribution changes and the total amount of the detected intensity IR of the light receiving element 2R decreases. All the decrease is detected on the IT side. Therefore, it can be considered that the distribution of IT is detected by reversing the intensity of IR.

IR and IT are obtained by dividing equation (5) by surface integral in the beam cross section. The result of the integration is shown in FIG. 8 (a) (the sample is tilted within a range of ± 4 degrees with respect to the case where the optical axis of the incident light and the sample surface are perpendicular to each other). As shown in FIG. 8A, when −0.8 ≦ (sample tilt angle: β) ≦ 0.8, the difference between IR and IT can be distinguished, but the larger the absolute value of β, the more IR. It becomes difficult to distinguish between IT and IT. It is preferably −0.7 ≦ β ≦ 0.7, more preferably −0.6 ≦ β ≦ 0.6, and even more preferably −0.5 ≦ β ≦ 0.5. 8 (b) is a standardization of the vertical axis of FIG. 8 (a) and a schematic representation of the horizontal axis in the range of 0 ≦ β ≦ 2. However, this experiment was performed with the working distance of the objective lens set to 125 mm, the beam diameter set to 8 mm, and the NA set to 0.031.

When the specific polarizing element 5 has rotational twist symmetry, for example, it may generate an axisymmetric polarized beam. This is an optical element in which the optical axes of the λ / 2 plate are distributed so as to be rotationally twisted and symmetrical, and has a function of converting linearly polarized light into an axisymmetric beam such as radial polarized light and azimuth polarized light.

As shown in FIG. 3, the specific polarizing element 5 has an angle α formed by the x-axis direction and the optical axis direction at a position separated by a distance r in a direction forming an angle θ degree with respect to the x-axis direction from the center (FIG. 3). It is preferable that the size of (not shown) increases or decreases as θ increases.

In FIG. 3, the specific polarizing element 5 is illustrated to be composed of compartments having different optical axes in the circumferential direction and a single optical axis in the radial direction, but the radiation of the specific polarizing element 5 is illustrated. It may be composed of a plurality of compartments having different optical axes in the direction. That is, it is preferable that the specific polarizing element 5 has a different Jones matrix depending on the position in the radial direction.

The size of the angle α is preferably (θ / 2) · n. However, n may be an arbitrary constant or a natural number.

A polarizing element generally called a q plate is an optical element in which the direction of the optical axis of the λ / 2 plate changes monotonically and constantly depending on its position in the circumferential direction. When the optic axis makes q rotations when it makes one rotation in the circumferential direction, the value is called the q value. When generating radial polarized light and azimuth polarized light from linearly polarized light, the q value is 1/2. In the present embodiment, a calculation is performed to confirm how the sensitivity of the measuring device changes when the q value changes. When the magnitude of the angle α representing the direction of the optical axis is (θ / 2) · n (n = 1), when the position θ in the circumferential direction of the polarizing element is 360 degrees (1 circumference), α changes by 180 degrees. Therefore, when n = 1, it corresponds to the q value being 1/2.

FIG. 9A assumes that the sample 4 to be measured has a smooth surface with 100% reflection, and R / is the amount by which the optical axis of the return light beam deviates from the optical axis of the incident light beam due to the inclination of the reflection surface. It is a graph which took r on the horizontal axis. The vertical axis is the intensity of Ir, which is the relative intensity when there is no deviation of the optical axis, that is, when the intensity when R / r = 0 is 1. From FIG. 9A, it can be seen that when the q value is less than 1/2, the sensitivity decreases, while the dynamic range increases. On the contrary, when the q value exceeds 1/2, the sensitivity in the low R / r region is improved. However, once Ir has decreased completely, it starts to increase again and an overshoot occurs. Therefore, although the sensitivity is high, vibrational sensitivity characteristics are generated, and Ir and R / r do not have a one-to-one correspondence, so that it is not suitable for specifying R / r. Therefore, in the sensitivity region in this case, the q value before vibration appears is preferably 1/2 or less. That is, it is preferable that n ≦ 1.

The specific polarizing element 5 may impart a phase difference that is an integral multiple of a quarter wavelength between the polarization component parallel to the optical axis and the polarization component perpendicular to the optical axis.

From FIG. 9A, it was found that Ir has the highest sensitivity when q = 1/2 under the condition that it does not show vibration behavior. Therefore, the birefringence phase difference of the q plate is limited to the case of q = 1/2. The sensitivity characteristics when the above was changed were evaluated. Not limited to the q plate, the birefringent polarizing element is affected by the wavelength dispersion, and the birefringence phase difference differs depending on the wavelength even for the same element. This means that when a white light source is used as the light source, the performance deteriorates with respect to light other than the design wavelength of the q plate. It is also an important point of view when considering how much performance can be expected when using a light source such as a monochromatic LED that is not white but has a narrow band. Since the actual wavelength dispersion differs depending on the product, in this embodiment, in addition to the original λ / 2 (phase difference π) of the q plate, λ / 4 (phase difference π / 2) and λ / 8 (phase difference) The sensitivity characteristics when π / 4) and 3λ / 4 (phase difference 3π / 2) were used were compared.

In FIG. 9B, the horizontal axis is R / r and the vertical axis is Ir, as in FIG. 9A. The result of 3λ / 4 is exactly the same as that of λ / 4, so it is omitted.

From FIG. 9B, when the birefringence phase amount is λ / 2, the sensitivity is saturated when R / r reaches 1, but in the case of λ / 4 and λ / 8, R / r is larger than 1. Has sensitivity even in the area. The reason for this is that R / r = 1 is the moment when the optical axis of the reflected beam shifts out of the incident beam, and after that, the light of the light intensity IR detected on the light receiving element 2R side shown in FIGS. 4 to 7. The intensity distribution becomes a radial stripe-like intensity distribution, and there is no significant change in geometry. Therefore, the change in the area ratio between the bright part and the dark part disappears, but the intensity of the dark part continues to decrease except when the birefringence phase amount is λ / 2. Further, the detection characteristics are different when R / r = 1 or less and more, and discontinuous sensitivity characteristics can be seen. This is because the sensitivity characteristics differ between the geometrical change in the intensity distribution and the subsequent intensity change in the dark area. This problem can be solved by adjusting the intensity distribution of the incident beam to obtain continuous sensitivity characteristics.

The magnitude of the angle α may be (a) gradually increased or decreased as θ increases, and (b) when the angle θ is within a predetermined range, α is constant and gradually increases as θ increases. May increase or decrease.

(Embodiment 3)
Next, the sample measuring device according to the third embodiment of the present invention will be described with reference to FIG. 10, which exemplifies the optical system on the light source side of the sample measuring device according to the first and second embodiments. Therefore, the same components are designated by the same reference numerals and the description thereof will be omitted. The characteristic of the third embodiment is the lighting system.

For an optical system that involves simultaneous irradiation of a plurality of beams, for example, the optical system is as shown in FIG. Specifically, camera image measurement by incoherent light source illumination is a typical example, and the number of beams in this case is considered to be infinite. Most camera image measurements fall into this category. In this case, the beam diameter is limited by using the aperture diaphragm in the illumination system. The diameter of all beams can be limited by applying a spatial transform element with a circular aperture to the Fourier plane where all beams are spatially coincident. Moreover, not only the sensitivity but also the sensitivity characteristics can be adjusted. Since it has a low sensitivity and high dynamic range in the high NA region and a high sensitivity and low dynamic range in the low NA region, it is necessary to add linearity to the sensitivity characteristics by adjusting the sensitivity characteristics by adjusting the transmittance in each region. You can also.

Therefore, the sample measuring device according to the embodiment of the present invention can be usefully applied to an optical system having a large working distance (small NA). Further, unlike a conventional interferometer, it is not necessary to make special preparations before observation, and such a simple optical system has not existed in the past. The NA value is preferably 0.3 or less, more preferably 0.2 or less, still more preferably 0.1 or less.

Also, the same thing can be done by adjusting the pattern of the polarization space conversion element. The pattern of the conversion element corresponds to M (r, θ) in the equation (5), but the pattern only needs to maintain rotational torsional symmetry, that is, torsional symmetry with respect to the radial direction θ. The symmetry order may be arbitrary, and the detection capability is exhibited even with the symmetry order 2. In this case, it is mirror-symmetrical and the shift detection direction is limited to the symmetrical plane direction, so that it can also be used for detecting the beam shift direction. There may also be a distribution that depends on the radial direction r, which can be used to adjust the characteristics of the sensitivity curve for beam shift detection.

Although the optical systems of FIGS. 2 and 6 are all described as reflection illumination systems, they can also be applied to transmission illumination optical systems by mirror-inverting the illumination optical system with respect to the sample surface.

In this way, the sensitivity can be adjusted by both the incident beam and the specific polarizing element 5, but the specific sensitivity setting is to determine the dynamic range with NA and adjust the sensitivity by adjusting the specific polarizing element 5. This method is effective when the observation target is fixed to some extent. Further, when the specific polarizing element 5 is not a non-variable optical element as shown in FIG. 1 but a variable optical element such as a liquid crystal is used, the generation of a pattern optimized for any observation target is dynamically generated. It can be carried out. When the specific polarizing element 5 is a reflection type, LCOS (LIQUID CRYSTAL ON SILICON) can be used.

FIG. 11 is a modification of the first to third embodiments, and is an example of an optical system in which the specific polarizing element 5 is a reflective type instead of a transmissive type.

In addition, although many polarizing elements are wavelength-dependent, this usage method works even under white light. However, it exhibits the highest sensitivity at the design wavelength.

Another feature of the sample measuring device according to the third embodiment is that it includes a polarizing beam splitter 3R for incident light on the light receiving element 2R and a polarizing beam splitter 3T for incident light on the light receiving element 2T. is there. In this case, the intensity of the light that can be received by the light receiving element 2R is half the intensity of the light that can be received by the light receiving element 2T. Therefore, even if a signal obtained by doubling the intensity of the light that can be received by the light receiving element 2R is used. good.

(Embodiment 4)
Next, the sample measuring device according to the fourth embodiment of the present invention will be described with reference to FIGS. 12 and 13, but the same optical elements as those of the sample measuring devices of the first to third embodiments will be described with the same reference numerals. Is omitted. The characteristic of the fourth embodiment is that the sample measuring device has an incident side specific polarizing element 51 and a reflection side specific polarizing element 52, and each specific polarizing element is one side (one side) of the sample 4 to be measured. ), And that the incident light and the reflected light on the measurement target sample 4 are not coaxial and both are oblique with respect to the normal direction of the measurement target sample 4. When the two specific polarizing elements 51 and 52 are arranged on one side of the measurement target sample 4 in this way, the aspect ratio of the obtained image is distorted because the observation image of the measurement target sample 4 faces from an oblique direction. However, depending on the surface shape of the sample 4 to be measured, the surface shape such as a step may be reflected in the image with good contrast when light is incident from an oblique direction. Further, if a plurality of observation images from different directions are obtained at the same location of the measurement target sample 4, the surface shape of the measurement target sample 4 can be observed with higher accuracy. For example, 360-degree image information can be obtained by rotating the measurement target sample 4 once in the normal axis direction around the point where the measurement target sample 4 and the optical axis of the sample measurement device intersect, and based on this information. A high-definition observation image can be obtained by a computer tomography method or the like. Further, since the incident light and the reflected light to the measurement target sample 4 are not parallel to each other, it is not necessary to separate the incident light from the reflected light by the beam splitter 3a. Therefore, the SN ratio of the reflected light is improved.

When the incident angle of light with respect to the measurement target sample 4 is shallow as shown in FIG. 12, it is preferable to individually arrange the incident side objective lens 71 on the incident side and the reflective objective lens 72 on the reflective side. On the other hand, when the angle of incidence on the sample 4 to be measured is deep as shown in FIG. 13, both the incident light and the reflected light can be incident on one objective lens 7.

(Other optional additional forms)
In FIGS. 4 to 7, the light intensity pattern changes even if the beam shift R / r exceeds 1, but as shown in FIG. 8, the change is saturated in the total light intensity obtained by integrating the changes. Be careful. You should choose which information to extract according to the optical system to be incorporated, the required sensitivity, and the dynamic range. Further, by acquiring the ratio of IT and IR, the measurement can be performed by canceling the difference in reflectance on the surface of the sample 4 to be measured. When observing on the specific polarizing element 5 with the light receiving element 2, if the light receiving element 2 is an array element, the above integral calculation is required for calculating IT and IR, but the light receiving element 2 is a single unit. A light receiving element having a light receiving unit does not need to perform integration processing, and is preferable for high-speed measurement.

The detection sensitivity of the sample measuring device can be adjusted by changing the size of the diameter 2r of the beam incident on the specific polarizing element 5. If the size of the specific polarizing element 5 has a sufficient margin, since the incident light is a single luminous flux in FIG. 2, the sensitivity can be adjusted by expanding or contracting the diameter of the incident beam. Further, the sensitivity can be adjusted by the NA of the objective lens. Such an optical system corresponds to laser scan image measurement and sensor measurement other than image measurement.

As the specific polarizing element 5, a liquid crystal element having a plurality of pixels can be used.

When a uniform polarization element is applied to a high NA objective lens, the polarization of the return light is not uniform and has a distribution depending on the incident angle. In this case, by measuring the distribution of IT and IR on the Fourier plane on which the polarization space filter is placed, it is possible to analyze the polarization characteristics including the incident angle as a parameter, thereby ellipsometry with high spatial resolution. It can be performed. The Fourier plane does not have to be a Fourier plane in a strict sense, and ellipsometry with a certain degree of spatial resolution can be performed by measuring the distribution of IT and IR on the plane defocused from the image plane. it can.

The additional configurations and effects of the embodiments will be described by the following (1) to (8).

(1) Quality stability Since the beam shift is determined by the light intensity ratio or difference measured by the two detectors ( light receiving elements 2T and 2R), it is not affected by the difference in reflectance and transmittance of the sample. In addition, since the illumination light is used for all measurements except absorption and eclipse in the optical system, a high-quality signal can be obtained even with an inexpensive detector, which is advantageous for high-speed measurement.

(2) Multi-beam application It can be applied to an optical system in which multiple beams are overlapped at the same time, and can be applied to wide-field observation corresponding to an infinite number of multi-beam measurements.

(3) Measurement limit It is possible to measure the minute inclination of the measurement area of the interferometer from the large inclination that cannot be measured by the interferometer. As a trial calculation, the measurement limit of the interference fringe pitch is 25 μm (1000 LPI). Assuming that the wavelength is 532 nm, the inclination at this time is 0.6 degrees. On the other hand, in an optical system in which an objective lens having an NA of 0.03 (F value 16 and a resolution of 15 μm) is inserted in FIG. 9 and a specific polarizing element 5 is inserted, as shown in FIG. 8, the region where IT / IR changes. Is 0.9 degrees or less, the sensitivity center is 0.45 degrees, and it can be seen that it is within the sensitivity range of the interferometer. By making the specific polarizing element 5 and NA variable, it is possible to extend the measurement to a larger inclination and exceed the measurement range of the interferometer.

(4) Specular reflection removal When observing a smooth glossy surface perpendicular to the optical axis, the brightness of the entire observation surface is extremely increased if the object side is a telecentric optical system, and the brightness of the center of the observation surface is extremely increased otherwise, especially in the latter case. The high-intensity part causes halation, which makes it difficult to observe the entire sample. By using the specific polarizing element 5, vertical reflection can be selectively removed, so that visibility can be improved. In addition, the removal characteristics can be adjusted by designing the specific polarizing element 5.

(5) Defect detection, step detection, and roughness detection As already described in the first embodiment, when a minute step is generated on the sample surface, a phase discontinuity corresponding to the height difference occurs, and the discontinuity occurs. A light wave with a beam shift is generated to compensate for this. It is possible to visualize spot-like and linear defects such as scratches, contamination, and minute steps created in the semiconductor process. Since the dark field measurement is performed when the measurement is performed on the light receiving element 2T side, it is possible to measure even a minute step by increasing the detector sensitivity. Further, if it is within the detection limit, it is possible to develop into step measurement by calibration with the IT / IR ratio. The detection range depends on the design of the specific polarizing element 5.

(6) Tilt measurement and waviness detection As already described in FIG. 2, it can be used for measuring the tilt of the sample 4 to be measured by the sample measuring device according to the embodiment. It is also possible to measure the swell of a seemingly flat surface by spatially integrating the tilt information. Since the swell is measured at a very low angle, it is easy to separate it from high-frequency components such as defects, roughness, and steps.

(7) Focus detection (wide-field confocal imaging)
When the sample surface is out of the focus of the observation optical system, the optical path of the reflected light changes as shown in FIG. 14, so focusing can be realized by measuring the beam shift. For example, an observation system using a telecentric optical system is constructed on the object side with an objective lens having a focal length f. At this time, the optical path shift amount Δx on the specific polarizing element 5 when the focus is deviated by Δf is expressed by the equation (8).

Here, x is the distance of the light beam from the main line of the optical system. As a result, a larger optical path shift can be obtained as the light beam passes through the optical path on the high NA side. Therefore, the optical path passing through the edge of the open pupil of the objective lens is focused by using, for example, the optical path of dark field illumination. The system is more effective. This is in symmetry with the fact that the central part has higher sensitivity than the peripheral part in beam shift detection, and three-dimensional measurement is performed by using the pupil of the objective lens in two parts. be able to.

(8) Cases to be observed The sample measuring device according to the first embodiment of the present invention is effective for the following cases to be observed.
1. 1. Surface observation
(A) Measurement of tilt and swell
(B) Contamination measurement of defects, particles, etc.
(C) Small steps formed by micro-patterning, etc.
(D) Roughness 2. Defect observation in bulk
(A) Observation of air bubbles in glass
(B) Detection of non-uniform refractive index due to distortion, etc.

This application claims the benefit of priority based on Japanese Patent Application No. 2019-156108 filed on August 28, 2019. The entire contents of the specification of Japanese Patent Application No. 2019-156108 filed on August 28, 2019 are incorporated herein by reference.

1 Light source 2 Light receiving element 3 Polarized beam splitter 3a Beam splitter 4 Sample to be measured 5 Specific polarized element 5a Section (region k)
5b section (area j)
5c section (area k)
5d compartment (area i)
5ax central axis 51 incident side specific polarizing element 52 reflective side specific polarizing element 6 linear polarizing plate 7 objective lens 71 incident side objective lens 72 reflection side objective lens 8 imaging lens

Claims (21)

1. A light source, a light receiving element that receives light emitted from the light source, and an optical element that is arranged on the light source side of the light source and selectively extracts light having a polarization component in a specific direction from the incident light. A sample measuring device having a sample measuring device, further comprising at least one of the following specific polarizing elements (1) and (2).
   (1) A specific polarizing element that is arranged on the light source side of the measurement target sample and transmits or reflects light emitted from the light source, and a measurement target that is arranged on the light receiving element side of the measurement target sample. Both specific polarizing elements that transmit or reflect light that has passed or reflected the sample.
   (2) It is arranged on the light source side of the measurement target sample and on the light receiving element side of the measurement target sample, transmits or reflects the light emitted from the light source, and reflects from the measurement target sample. A specific polarizing element that transmits or reflects the emitted light.
   [Specific polarizing element]
   A transmissive or reflective polarizing element having an in-plane x-axis direction and a y-axis direction orthogonal to the x-axis direction, in which the Jones matrix differs depending on the in-plane position.
2. The sample measuring device according to claim 1, which has both of the specific polarizing elements specified by (1) of claim 1, and both of the specific polarizing elements are arranged on one side of the sample to be measured.
3. When the light incident on the region Rin in the xy plane of the specific polarizing element is incident on the region Rout located at the position of the central axis of the specific polarizing element with respect to the region Rin, the light transmitted through the region Rout The sample measuring device according to claim 1 or 2, wherein the Jones vector is the same as the Jones vector of light incident on the region Rin.
4. The specific polarizing element has M regions (R1 to RM) in the xy plane, and the region Ri and the region Rj located at a position symmetrical with respect to the central axis of the specific polarizing element with respect to the region Ri. The sample measuring device according to any one of claims 1 to 3, which has a region Rk adjacent to the region Rj and satisfies the following conditions A and B.
   [Condition A]
   When the light whose Jones vector is Jxy is incident on the region Ri and the transmitted light is further incident on the region Rj, the Jones vector of the light transmitted through the region Rj is the same as that of Jxy.
   [Condition B]
   The Jones matrix of region Rk is different from the Jones matrix of region Rj.
   However, the above i, j, k, and M are natural numbers, respectively.
5. In the specific polarizing element, the magnitude of the angle α formed by the x-axis direction and the optical axis direction at a position separated by a distance r in the direction forming an angle θ degree with respect to the x-axis direction from the center increases by θ. The sample measuring apparatus according to any one of claims 1 to 4, which is increasing or decreasing in accordance with the above.
6. The sample measuring device according to any one of claims 1 to 5, wherein the specific polarizing element has a Jones matrix different depending on the position in the radial direction.
7. The sample measuring device according to any one of claims 4 to 6, wherein the magnitude of the angle α is (θ / 2) · n. However, n is an arbitrary constant.
8. The sample measuring device according to claim 7, wherein n is 1.0 or less.
9. The sample measuring device according to any one of claims 4 to 8, wherein the magnitude of the angle α is (θ / 2) · n. However, n is an integer.
10. The sample measuring device according to any one of claims 4 to 9, wherein the magnitude of the angle α gradually increases or decreases as θ increases.
11. The item according to any one of claims 4 to 9, wherein the α is constant when the angle θ is within a predetermined range, and the magnitude of the angle α gradually increases or decreases as θ increases. Sample measuring device.
12. The sample measuring device according to any one of claims 1 to 11, wherein an objective lens is arranged between the specific polarizing element and the sample to be measured.
13. The light receiving element is composed of a first light receiving element and a second light receiving element. The optical element is a polarizing beam splitter, and the light reflected by the polarizing beam splitter is received by the first light receiving element. The sample measuring apparatus according to any one of claims 1 to 12, wherein the light transmitted through the polarizing beam splitter is received by the second light receiving element.
14. The specific polarizing element gives a phase difference that is an integral multiple of a quarter wavelength between a polarization component parallel to the optical axis and a polarization component perpendicular to the optical axis, according to claims 1 to 13. The sample measuring apparatus according to any one item.
15. The sample measuring device according to any one of claims 1 to 14, wherein the light receiving surface of the light receiving element is a Fourier surface of the sample to be measured.
16. A light source, a light receiving element that receives light emitted from the light source, and an optical element that is arranged on the light source side of the light receiving element and selectively extracts light having a polarization component in a specific direction from the incident light. The step of preparing a sample measuring device including at least one of the following (1) and (2) specific polarizing elements, and
    The step of emitting light from the light source and
    The step of detecting the light passing through the sample to be measured by the light receiving element, and
    Measurement method having.
    (1) A specific polarizing element that is arranged on the light source side of the measurement target sample and transmits or reflects light emitted from the light source, and a measurement target that is arranged on the light receiving element side of the measurement target sample. Both specific polarizing elements that transmit or reflect light transmitted or reflected by the sample.
    (2) It is arranged on the light source side of the measurement target sample and on the light receiving element side of the measurement target sample, transmits or reflects the light emitted from the light source, and reflects from the measurement target sample. A specific polarizing element that transmits or reflects the emitted light.
    [Specific polarizing element]
    A transmissive or reflective polarizing element having an in-plane x-axis direction and a y-axis direction orthogonal to the x-axis direction, in which the Jones matrix differs depending on the in-plane position.
17. The measuring method according to claim 16, wherein the specific polarizing element is divided into a plurality of regions in a plane, some of the plurality of regions are optical rotations, and the other plurality of regions are not optical rotations.
18. The specific polarizing element is a polarizing element in which the direction of the optical axis differs depending on the position in the plane, and is the x-axis direction at a position separated by a distance r from the center in a direction forming an angle θ degree with respect to the x-axis direction. The measuring method according to any one of claims 15 to 17, wherein the magnitude of the angle α formed with the optical axis direction increases or decreases as θ increases.
19. In the sample measuring device
    (A) The light receiving element is composed of a first light receiving element and a second light receiving element, and the optical element is a polarizing beam splitter.
    (B) The light reflected by the polarization beam splitter is received by the first light receiving element, and the light transmitted by the polarization beam splitter is received by the second light receiving element.
    Any one of claims 15 to 18, further comprising a step of calculating the ratio or difference between the light intensity detected by the first light receiving element and the light intensity detected by the second light receiving element. The measurement method described in.
20. When the light incident on the region Rin of the specific polarizing element is incident on the region Rout located at the position of the central axis of the specific polarizing element with respect to the region Rin, the Jones vector of the light transmitted through the region Rout is: The measuring method according to any one of claims 15 to 19, which is the same as the Jones vector of light incident on the region Rin.
21. The specific polarizing element has M regions (R1 to RM) in the xy plane, and the region Ri and the region Rj located at a position symmetrical with respect to the central axis of the specific polarizing element with respect to the region Ri. The measuring method according to any one of claims 15 to 20, which has a region Rk adjacent to the region Rj and satisfies the following conditions A and B.
    [Condition A]
    When the light whose Jones vector is Jxy is incident on the region Ri and the transmitted light is further incident on the region Rj, the Jones vector of the light transmitted through the region Rj is the same as that of Jxy.
    [Condition B]
    The Jones matrix of region Rk is different from the Jones matrix of region Rj.
    However, i, j, k, and M are natural numbers, respectively.

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