KR101280335B1 - Method and apparatus for measuring optical aeolotropic parameter - Google Patents

Abstract

The present invention provides a method and apparatus for measuring the direction, size, and thickness of an optical axis of an optically anisotropic thin film at high speed and with high accuracy, and for enabling distribution measurement by a two-dimensional light receiving element.

The monochromatic light of P-polarized light is irradiated at a predetermined incidence angle from a plurality of incidence directions set at predetermined angular intervals centered on the normal line Z standing at the measuring point M, and the reflected light intensity of the S-polarized light included in the reflected light is incident direction Is detected according to the measured incidence direction ν ₁ based on the incident value ν ₁ , which is detected according to the minimum value V ₁ sandwiched between two local maximum values Λ ₁ and Λ ₂ , which become maximum peaks among the incident directions representing the minimum values of the reflected light intensity. The azimuth direction (Φ _A ) of the optical axis OX in the s) is determined, and the minimum value V ₃ embedded in the maximum value Λ ₁ as the maximum peak and the maximum value Λ ₃ as the intermediate peak adjacent thereto is measured. The polar angle direction θ was determined based on the incident direction.

Polar angle, azimuth angle, local maximum, local minimum, peak, anisotropy, parameter, optical, thin film, polarized light, normal, light emitting optical system, light receiving optical system

Description

Optical anisotropy parameter measuring method and measuring device {METHOD AND APPARATUS FOR MEASURING OPTICAL AEOLOTROPIC PARAMETER}

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows an example of the optically anisotropic parameter measuring apparatus which concerns on this invention.

2 is a conceptual diagram showing the relationship between the azimuth direction and the polar angle direction of the optical axis.

3 is a graph showing the measurement results.

4 is an explanatory diagram showing another optically anisotropic parameter measuring apparatus.

5 is an explanatory diagram showing the positional transition of each measuring point according to the rotation of the thin film sample.

6 is an explanatory diagram showing a polar angle distribution.

7 is an explanatory diagram showing still another optically anisotropic parameter measuring apparatus.

8 is a graph showing the measurement results.

9 is a graph showing the measurement results.

[Description of Symbols]

1, 31, 41: optically anisotropic parameter measuring device

2: stage 3: thin film sample

OX: optical axis Φ _A : azimuth direction

θ: polar angle M: measuring point

Z: normal 4: luminescence optical system

5: light receiving optical system 6: arithmetic processing unit

This invention relates to the optical anisotropy parameter measuring method and measuring apparatus which measure the anisotropy of the optical axis of a thin film sample, and is especially suitable for using for the inspection of a liquid crystal aligning film, etc.

A liquid crystal display has a rear glass substrate laminated with a transparent electrode and an alignment film on the surface, and a front glass substrate laminated with a color filter, transparent electrode and an alignment film formed on the surface so that the alignment films face each other with spacers therebetween, and between the alignment films. It is sealed in the state which enclosed the liquid crystal, and the polarizing filter was laminated | stacked on both sides before and behind.

Here, in order for the liquid crystal display to operate normally, the liquid crystal molecules need to be uniformly arranged in the same direction, and the alignment film determines the orientation of the liquid crystal molecules.

This alignment film can align the liquid crystal molecules because it has uniaxial optical anisotropy, and if the alignment film has uniform uniaxial optical anisotropy over its entire surface, it is difficult to cause defects in the liquid crystal display. The presence of non-uniform optical anisotropy disturbs the direction of the liquid crystal molecules, resulting in a defective liquid crystal display.

That is, the quality of the alignment film affects the quality of the liquid crystal display as it is. If the defect is in the alignment film, the orientation of the liquid crystal molecules is disturbed, which causes defects in the liquid crystal display.

Therefore, when assembling the liquid crystal display, if the alignment film is inspected for defects in advance and only the alignment film with stable quality is used, the yield of the liquid crystal display is improved and the production efficiency is improved.

Accordingly, a method of inspecting defects by conventionally measuring azimuth direction, polar angle direction, thickness, etc. of the optical axis serving as anisotropic parameters with respect to the alignment film and evaluating optical anisotropy of the alignment film has been proposed.

The most common method is to use an ellipsometer to measure fairly accurately, but the measurement time per measurement point is as long as 2 minutes, and when evaluating the anisotropy of one alignment layer, only a total work of 100 × 100 If the point is to be measured, it takes about two weeks by simple calculation, so it is impossible to carry out a full inspection on the production line.

This is irradiated monochromatic light of P-polarized light or S-polarized light with respect to the measuring point at a predetermined incident angle from a plurality of incidence directions set at predetermined angular intervals centered on the normal line established at the measuring point of the thin film sample, and among the polarization components included in the reflected light. By measuring the reflected light intensity of the polarization component orthogonal to the polarization direction of the irradiation light, the azimuth direction, polar angle direction and thickness serving as parameters of the optically anisotropic thin film are detected by detecting the change in the reflected light intensity according to the incident direction.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2001-272308

However, according to this, in order to obtain the parameters of the optically anisotropic thin film, this method requires a measurement in all orientations, so there is a problem that it takes time.

In addition, since the measurement requires an absolute amount of reflected light intensity, the measurement precision is influenced by external factors such as the linearity and dynamic range of the sensitivity of the light receiving element, and the error is likely to be large. There is a problem that improvement is difficult.

In addition, the nonlinear least-squares method needs to simultaneously calculate six or more parameters of the direction and magnitude of the main dielectric constant, the thickness of the film, and the standardization constant, which may lead to a solution that converges to a local minimum. In addition, there is a problem that a large amount of time is required for calculation.

Therefore, it is a technical subject of this invention to provide the method and apparatus which can measure the direction and inclination of the optical axis of an optically anisotropic thin film at high speed and high precision, and also enable distribution measurement by a two-dimensional light receiving element.

In order to solve this problem, the present invention is an optical anisotropy parameter measuring method for measuring the azimuth direction and the polar direction of the optical axis as anisotropic parameters of a thin film sample, and is set at predetermined angular intervals centered on a normal line established at a measuring point on the thin film sample. The monochromatic light of P-polarized light or S-polarized light is irradiated with respect to the said measuring point from a some incidence direction, and the reflected light intensity of the polarization component orthogonal to the polarization direction of irradiation light among the polarization components contained in the reflected light according to the incident direction The azimuth angle of the optical axis at the point of measurement based on the incident direction of detection and based on the incident direction in which the minimum value interspersed between the two maximums at the maximum peak among the incident directions representing the minimum value of the reflected light intensity or the two maximums at the middle peak is measured Determine the direction, the reflected light The minimum value interposed between the maximum value at which the maximum peak becomes the maximum value and the maximum value being the intermediate peak adjacent thereto determines that the polar angle direction of the optical axis at the measuring point is determined based on the measured incidence direction or the maximum value maximum incident peak value is measured. It features.

(Example)

In order to achieve the object of measuring the direction and inclination of the optical axis of an optically anisotropic thin film at high speed and with high accuracy, the present invention relates to the measurement points from a plurality of incidence directions set at predetermined angular intervals centered on normals established at measurement points on a thin film sample. The monochromatic light of P polarization or S polarization is irradiated at a predetermined incident angle, and the reflected light intensity of the polarization component orthogonal to the polarization direction of the irradiation light among the polarization components included in the reflected light is detected along the incidence direction, and the minimum value of the reflected light intensity is detected. The minimum value interposed between two local maximum values among the maximum incident incidence directions is determined based on the measured incident direction to determine the azimuth direction of the optical axis at the measurement point, and the maximum value at which the reflected light intensity becomes the maximum peak and the intermediate peak adjacent thereto. The local minimum between the maximum local values On the basis of this, the polar angle direction of the optical axis at the measuring point was determined.

1 is an explanatory diagram showing an example of an optical anisotropy parameter measuring apparatus according to the present invention, FIG. 2 is a conceptual diagram showing the relationship between the incident direction indicating the minimum value of the reflected light intensity and the azimuth direction and the polar angle direction of the optical axis, and FIG. 4 is an explanatory diagram showing another optical anisotropy parameter measuring apparatus, FIG. 5 is an explanatory diagram showing the positional transition of each measuring point according to the rotation of the thin film sample, and FIG. 6 is an explanatory diagram showing the measurement result of the inclination angle distribution. Fig. 7 is an explanatory diagram showing still another optically anisotropic parameter measuring apparatus, and Figs. 8 and 9 are graphs showing the measurement results.

≪ Example 1 >

The optically anisotropic parameter measuring apparatus 1 shown in FIGS. 1 and 2 has an azimuth direction Φ _A of the optical axis OX serving as an anisotropic parameter of the thin film sample 3 mounted on the stage 2 and a polar angle direction θ. ), P polarized light or S polarized light with respect to the measuring point M from a plurality of incidence directions set at predetermined angular intervals centered on a normal line Z set at the measuring point M on the thin film sample 3. A light emitting optical system 4 for irradiating monochromatic light at a predetermined incident angle, and a light receiving optical system 5 for detecting the reflected light intensity of a polarization component orthogonal to the polarization direction of the irradiation light among the polarization components included in the reflected light according to the incidence direction; and The arithmetic processing unit 6 which determines the polar angle direction of the optical axis in the measuring point M based on the measurement result is provided.

The stage 2 includes an elevating table 12 for elevating the stage 2 on the base 11, a rotary table 13 for rotating the stage 2, and the stage 2 of the rotating table 13. The XY table 14 which horizontally moves to the XY direction with respect to the rotation center Z, and the tilt adjustment table 15 which adjusts the tilt of the stage 2 at the time of rotation of the rotation table 13 are provided.

Moreover, above the stage 2, the auto collimator 7 which optically measures the tilt amount of the stage 2 is arrange | positioned, and the tilt amount is adjusted based on the measurement result.

The light-emitting optical system 4 has an angle of incidence near the Brewster's angle where the He-Ne laser 21 having a wavelength of 632.8 nm and a light intensity of 25 mW is directed toward the rotation center Z of the rotation table 13 with better measurement accuracy. In this example, the polarizers 22 and 22, which are arranged to be 60 °, and are made of two Glan-Thompson prisms (extinction ratios 10 ^-6 ), which transmit P polarization along the irradiation optical axis L _IR , In this way, only pure P polarization can be irradiated.

The light receiving optical system 5 includes a pinhole slit 23 for canceling light due to back reflection from the sample 3 along the reflected optical axis L _RF irradiated from the laser 21 and reflected from the thin film sample 3. And an analyzer (24, 24) composed of two Glenthomson prisms (extinction ratio 10 ^-6 ) that transmit S polarized light, and a wavelength selective filter (25) and a photomultiplier (26). The detection signal of the pipe 26 is output to the arithmetic processing unit 6.

In addition, by using two analyzers 24, only pure S polarization can be detected by the photomultiplier 26. As shown in FIG.

The arithmetic processing unit 6 inputs a detection signal output from the photomultiplier tube 26 each time the rotation table 13 is rotated by a predetermined angle, and stores the relationship between the rotation angle (incidence direction) and the reflected light intensity.

The change in the reflected light intensity detected when the incidence direction is changed from 0 to 360 ° with respect to the thin film sample 3 having optical anisotropy is generally the maximum peak as shown in the graph G ₁ of FIG. 3. It becomes a waveform which has four local values Λ ₁ , Λ ₂ , two local maximums Λ ₃ , Λ ₄ serving as intermediate peaks, and four local values V _{1 to} V ₄ between each of them.

That is, as shown in FIG. 2, when viewed from the longitudinal direction of the optical axis OX in a plan view, the minimum values V ₁ and V ₂ are measured, and the longitudinal axis including the optical axis OX is measured on the optical axis. The minimum values (V ₃ , V ₄ ) are measured when incident from the direction orthogonal to the angle.

The minimum value V ₁ sandwiched between two local maximum values Λ ₁ and Λ ₂ , which are the maximum peaks among the incident directions ν ₁ to ν ₄ representing the minimum values of the reflected light intensity, is based on the measured incident direction ν ₁ . The azimuth direction Φ _A of the optical axis at the measuring point is determined. In other words, the incidence direction ν ₁ is defined as the azimuth direction Φ _A = 0.

Then, the reflected light intensity is maximum value (Λ ₁₎ and its maximum value is in the middle of the peak adjacent to (Λ ₃₎ a minimum value (V ₃₎ is measured incident direction (ν _3), the reflected light intensity fitted to be the maximum peak to the maximum peak that maximum value (Λ ₂₎ and its maximum value is in the middle of the peak adjacent extreme values are in (Λ ₄₎ a minimum value (V ₄₎ incident direction (ν ₄₎ or a maximum peak is measured sandwiched (Λ ₁ or Λ ₂₎ measurement The polar angle direction [theta] of the optical axis at the measurement point is determined based on the incident direction [lambda] ₁ or [lambda] ₂ .

In such a case, when calculating based on Formula (2),

Φ _B = ν ₃ -ν ₁ = ν ₄ -ν ₁

When calculating based on Formula (3)

| Φ _C | = | Φ _D | = | λ ₁ -λ ₂ | / 2 = | λ ₃ -λ ₄ | / 2

.

The above is an example of a structure of the apparatus of the present invention, and the method of the present invention is described next.

Then, since the azimuth direction Φ _A and the polar angle direction θ of the optical axis OX of the thin film sample 3 are already known, the measurement is performed by using an ellipsometer or reflectometer from any two directions. The magnitude and thickness of the main dielectric constant of the sample can be obtained.

As a thin film sample 3, a polyamic acid (PI-C manufactured by NISSAN CHEMICAL INDUSTRIES, LTD) was spin-coated on a glass substrate 8 by a spin coater, and then calcined at 260 ° C., followed by rubbing with a buff cloth. It was.

It was thickness (T = 80 nm) and dielectric constant ((epsilon = 3.00)) of the thin film before rubbing.

The sample 3 after rubbing was previously measured by a conventionally known method. When the rubbing direction was 0 °, the azimuth direction (ν ₁ = 0.7 °) of the optical axis OX, and the polar angle direction (θ = 24.2 °) , The normal light permittivity (ε ₀ = 2.83), the abnormal light permittivity (ε _e = 3.43), and the thickness of the anisotropic layer (t = 12 nm). The measurement time at this time was about 60 seconds at one measurement point.

The thin film sample 3 was placed on the stage 2, and the tilt amount of the sample was detected by the auto collimator 7, and the sample 3 was adjusted to be horizontal in the tilt adjustment table 15. In addition, the height of the sample 3 was optimized by the lifting table 12 so that the reflected light from the sample 3 enters the light receiving element.

After the tilt and height adjustment of the sample 3, the rotating table 13 was rotated, and the reflected light intensity of the S-polarized light with respect to the incident direction was measured.

The rubbed thin film sample 3 can be expected that the azimuth direction Φ _A is approximately parallel to its rubbing direction (X direction), and it can be expected that the polar angle direction θ is at a position substantially orthogonal to it. In the example, the reflected light intensity was measured at a 2 ° interval in a range of ± 20 ° about the rubbing direction and ± 20 ° about the direction perpendicular to the rubbing direction (Y direction).

In addition, this measurement range may be set to arbitrary angle ranges, such as +/- 45 degrees and +/- 30 degrees, considering the difference between the predicted azimuth direction of the optical axis and the actual azimuth direction measured empirically.

3 are enlarged graphs G ₂ and G ₃ of the reflected light intensity change in each measurement range around the X and Y directions.

From this measurement data, the azimuth direction Φ _A and the polar angle direction θ of the optical axis OX were obtained.

When the inclination angle θ was obtained, the normal light dielectric constant of formula (2) was set to the dielectric constant (ε ₀ = 3.00) of the polyimide film before rubbing.

Was made performs a fitting calculation with respect to the measurement result of the graph (G _2), calculates the orientation (ν ₁₎ a light receiving intensity that is a minimum, it was ν ₁ = 0.4 °. Therefore, it can be seen that the azimuth direction Φ _A of the optical axis OX is inclined at 0.4 ° from the Y axis.

In addition, fitting calculations are performed on the measurement results of the graph G ₃ , the orientation ν ₃ at which the received light intensity is minimized is calculated, Φ _B = ν ₃ −ν ₁ , and the normal optical permittivity (ε _O = 3.00) ( The inclination angle θ was calculated based on the formula (2) as the permittivity of the polyimide film before rubbing), and θ was 22.5 °.

In addition, the measurement time of one measuring point at this time was about 2 seconds.

As a result deoni the background to have done the measurement by the ellipsometer in both the direction of the optical axis of the sample azimuth direction and the direction perpendicular to this, steady light dielectric constant (ε _O = 2.79), or more optical dielectric constant (ε _e = 3.44), anisotropically The thickness of the layer (t = 11 nm). It was 24.5 degrees when the inclination angle (theta) was recalculated from the value of this normal optical permittivity (epsilon _O ).

At this time, even if the time measured by an ellipsometer was added, the measurement time was about 4 seconds per measurement point, and the result equivalent to the conventional method could be measured at high speed.

<Example 2>

FIG. 4 shows another embodiment of the optically anisotropic parameter measuring apparatus. Parts common to those of FIG. 1 are denoted by the same reference numerals and detailed description thereof will be omitted.

In the optically anisotropic parameter measuring device 31 of the present example, the light emitting optical system 4 is arranged with a xenon lamp 32, and the pinhole slit 34 at the condensing point of the reflecting mirror 33 along its irradiation light axis L _IR , The collimating lens 35 which makes transmitted light parallel, the interference filter 36, and the polarizer 22 which transmits P polarization is arrange | positioned.

At this time, the interference filter 35 is selected with a center wavelength of 450 nm and a full-width at half-maximum (FWHM) of 2 nm, the beam diameter irradiated to the thin film sample 3 is 10 mm ² , and the incidence angle is the Brewster angle. It set so that it might become near 60 degrees.

In the light receiving optical system 5, an analyzer 24, a wavelength selective filter 37, and a two-dimensional CCD camera 38 for transmitting S-polarized light are arranged along the reflection optical axis L _RF .

Thereby, the reflected light intensity from the some measurement point Mij contained in the 10 mm <^2> measurement area | region A irradiated to the sample 3 can be measured simultaneously.

Sample 3 was prepared by spin coating a polyamic acid (PI-C manufactured by NISSAN CHEMICAL INDUSTRIES, LTD.) On a Si substrate, firing at 260 ° C., and rubbing with a buff cloth. At the time of rubbing, rubbing was performed on the right side of the sample 3 so as to increase the rubbing strength.

When the inclination angle θ of this sample 3 was measured by 10 × 10 = 100 points by a conventional method, the distribution was 30 to 34 degrees on the right side and 27 to 29 degrees on the left side.

In addition, the measurement time was about 100 minutes at 100 points.

After the sample 3 was installed in the stage 2, the tilt and height were adjusted, the rotating table 13 was rotated, and the two-dimensional distribution measurement of the reflected light intensity with respect to the incident direction was performed.

Fig. 5A shows the measuring point Mij (i, j = 1 to 10) in the measuring area A before rotation.

FIG. 5 (b) shows an image rotated according to the rotation of the turntable 13. When each measurement point Mij is represented by polar coordinates (Mij = (r _n , α _m )), the turntable 13 is The position of Mij when rotated by the angle γ is represented by Mij = (r _n , α _m + γ).

Therefore, the reflected light intensity may be measured in the pixel region of the CCD camera 39 corresponding to Mij = (r _n , α _m + γ).

Thus, for each measuring point (Mij) of 100 points in total, in the same manner as in Example 1, the range of ± 20 ° about the rubbing direction (X direction) and ± 20 ° about the direction orthogonal to this (Y direction) The reflected light intensity was measured at 2 ° intervals at, and the distribution of the inclination angle (θ) was obtained using Equation (7). The measurement time of the measuring point of 100 points at this time was 2 seconds.

Based on this result, the measurement is performed with an ellipsometer in two directions of the azimuth direction Φ _A of the optical axis OX and a direction orthogonal to each measurement point Mij of the sample, and the normal optical permittivity ε _O , The ideal optical dielectric constant (ε _e ) and the thickness t of the anisotropic layer were measured.

FIG. 6 shows the distribution of the inclination angle θ recalculated from the measured value of the normal photo permittivity ε _O.

According to this, the distribution of 30-34 degrees on the right side and 27-29 degrees on the left side obtained the same result as the conventional method measured.

At this time, even if the time measured by an ellipsometer was added, the measurement time with respect to the measuring point of 100 points was about 6 seconds, and the result equivalent to the conventional method was able to be measured very quickly.

<Example 3>

FIG. 7 shows another embodiment of the optically anisotropic parameter measuring apparatus, and parts common to those of FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

The optically anisotropic parameter measuring device 41 of this example measures the optically anisotropic parameter without rotating the sample 3.

The emission optical system 4 measures the measurement point M at an angle of incidence near the Brewster angle (60 ° in this example) in a range of ± 20 ° about the rubbing direction (X direction) and ± 20 ° about the Y direction perpendicular to it. A plurality of irradiation optical axes L _IR for irradiating light toward the light beams are set at 5 ° intervals.

On each irradiation optical axis L _IR , a semiconductor laser 42 having a wavelength of 780 nm and an optical intensity of 20 mW, and a polarizer 22 for transmitting P polarized light are arranged.

The light receiving optical system 5 is irradiated from each laser 42 and pinhole slit 23 for canceling light due to back reflection from the sample 3 along each of the reflected optical axes L _RF reflected from the thin film sample 3. ), A analyzer 24 for transmitting S polarized light, a wavelength selective filter 25 and a photomultiplier tube 26 are arranged, and the detection signal of each photomultiplier tube 26 is output to the arithmetic processing unit 6. It is supposed to be.

The sample 3 was spin-coated a polyamic acid (PI-C manufactured by NISSAN CHEMICAL INDUSTRIES, LTD) on a glass substrate (white plate glass) by a spin coater, and then fired at 260 ° C., followed by rubbing with a buff cloth. It was.

It was thickness (T = 93 nm) and dielectric constant (ε = 2.98) of the thin film before rubbing.

The sample 3 after rubbing was previously measured by a conventionally known method. When the rubbing direction was 0 °, the azimuth direction (ν ₁ = 1.5 °) and the polar angle direction (θ = 20.4 °) of the optical axis OX were obtained. , The normal optical dielectric constant (ε ₀ = 2.78), the abnormal optical dielectric constant (ε _e = 3.32), and the thickness of the anisotropic layer (t = 12 nm). The measurement time at this time was about 60 seconds at one measurement point.

After adjusting the tilt and height of the thin film sample 3, the reflected light intensity of the light output from each laser 42 was measured.

8 and 9 are measurement data in an angular range of ± 20 ° about the X direction (180 °) and the Y direction (90 °), respectively.

Fitting calculations were performed with respect to the measurement results in FIG. 8, and the direction ν ₁ at which the received light intensity was minimized was calculated, and ν ₁ = 1.8 °. Therefore, it can be seen that the azimuth direction Φ _A of the optical axis OX is inclined 1.8 ° from the Y axis.

In addition, fitting calculations are performed on the measurement results in FIG. 9 to calculate a direction (ν ₃ ) in which the received light intensity is minimized, Φ _B = ν ₃ -ν ₁ , and the normal optical permittivity (ε _O = 2.98) (poly is before rubbing. The inclination angle θ was calculated based on the formula (2) as the dielectric constant of the mid film), and θ was 19.0 °.

In addition, the measurement time of one measuring point at this time was about 0.5 second.

Based on these results, measurements were made with an ellipsometer in two directions, the azimuth direction of the optical axis of the sample and the direction orthogonal to the specimen, and showed a normal optical permittivity (ε _O = 2.76), an abnormal light permittivity (ε _e = 3.38), The thickness of the layer (t = 16 nm). It was 20.5 degrees when the inclination angle (theta) was recalculated from the value of this normal optical dielectric constant (epsilon _O ).

At this time, even if the time measured by an ellipsometer was added, the measurement time was about 2 seconds per measurement point, and the result equivalent to the conventional method was able to be measured at high speed.

According to the present invention, first, the monochromatic light of P-polarized light or S-polarized light is irradiated with respect to the measuring point at a predetermined incidence angle from a plurality of incidence directions set at predetermined angular intervals centered on the normal line established at the measuring point on the thin film sample, The change of the reflected light intensity according to the incident direction is detected by measuring the reflected light intensity of the polarization component orthogonal to the polarization direction of irradiation light among the polarization components included.

When the incident direction was changed between 0 and 360 °, the measured value of the reflected light intensity of the thin film sample having optical anisotropy was adjacent to the two local maximum peaks while the two local maximum peaks were adjacent to each other. And a waveform having four local minimums between the local maximums.

Here, the angle of the azimuth direction of the optical axis of the thin film sample, that is, the direction of the optical axis in the measurement plane is the same as the measured value of the local minimum between the two maximum values that become the maximum peak, so that the direction is determined as the azimuth direction, The angle is placed in the azimuth direction (Φ _A = 0) at the measuring point.

This direction can also be specified in the direction in which the local minimum between the two local maximum peaks is 180 ° away from the direction in which it is measured, so that the local minimum between the local maximum peaks is measured.

Next, the angle of the polar angle direction of the optical axis of a thin film sample, ie, the inclination angle of the optical axis with respect to a board | substrate plane, can be computed by Formula (2) or Formula (3).

Here, since the variables other than the angle θ in the polar angle direction are all known or measured values in the formulas (2) and (3), the maximum value that becomes the maximum peak and the maximum value that becomes the intermediate peak in Equation (2) It can be calculated by detecting the angle at which the minimum value sandwiched between is measured, and by detecting the angle at which the maximum value, which is the maximum peak, is measured by Equation (3).

Φ _A : Direction of incidence where the minimum value between the two maximum values at the maximum peak is measured (= azimuth direction = 0)

Φ _B : Incident direction in which the minimum value interposed between the maximum value at the maximum peak and the maximum value at the intermediate peak is measured

Φ _C : Incident direction where the maximum value at which the maximum peak is measured is measured

Φ _D : Incident direction where the maximum value at which the maximum peak is measured is measured

θ: angle (inclined angle) in the polar angle direction of the optical axis from the substrate plane

μ: +/- (“+” when the reflection intensity of P-polarized light is incident to S-polarized light, “-” when the reflection intensity of S-polarized light is incident to P-polarized light)

φ ₀ : incident angle of the thin film

φ ₂ : angle of light when entering the substrate

N ₂ : Refractive index of substrate

ε ₀ : normal photo permittivity of thin film sample

Further, the monochromatic light of P-polarized light or S-polarized light is irradiated to a predetermined measurement region on the thin film sample at a predetermined incident angle, and the reflected light intensity distribution of the polarized light component orthogonal to the polarization direction of the irradiated light is polarized among the polarized light components included in the reflected light. By detecting by, the azimuth direction and the polar angle direction can be calculated individually with respect to a some measurement point by detecting the reflected light intensity with respect to each measurement point which exists in a measurement area according to an incident direction.

In addition, when a liquid crystal aligning film is used as a thin film sample, for example, an optical axis is aligned by rubbing, and there exists an extreme value which minimizes the reflected light intensity when it enters from the vicinity of the rubbing direction and the direction orthogonal to this.

In addition, the angle (direction) at which the maximum value at which the reflected light intensity becomes the maximum peak or the middle peak exists depends on the polar angle direction, and when manufacturing the liquid crystal alignment film, the polar angle direction is empirically controlled by the rubbing intensity (pressure). Can be specified from equation (3) based on the polar angle direction.

Therefore, the light is incident in a predetermined angle range, for example, in the rubbing direction and the direction orthogonal to the rubbing direction, or the predetermined angle is determined around the angle (direction) where the maximum value at which the rubbing direction and the reflected light intensity become the maximum peaks is present. The measurement range can be narrowed by injecting light in the angular range.

In addition, such an angular range is sufficient based on a statistical deviation such as the azimuth direction measured empirically in the manufacturing line of the liquid crystal alignment film, etc., and if the deviation is small, a limited range of about ± 20 ° is sufficient, and ± 45 ° when the deviation is large. Just broaden the range.

Thus, knowing only the minimum and maximum incidence directions of the reflected light can determine the azimuth and polar directions of the optical axis, and the values of the anisotropic layer of the thin film sample (t) and the normal light permittivity (ε ₀ ) for the known measuring points. In the case of measuring the abnormal optical dielectric constant ε _e , it is sufficient to perform measurements with an ellipsometer or reflectometer from two to three directions, and these optical anisotropy parameters can be measured accurately in a very short time.

[Industry availability]

Industrial Applicability The present invention can be applied to quality inspection of thin film products having optical anisotropy, in particular, liquid crystal alignment film.

Claims (13)

An optical anisotropy parameter measuring method for measuring azimuth and polar directions of an optical axis serving as anisotropic parameters of a thin film sample, The monochromatic light of P-polarized light or S-polarized light is irradiated with respect to said measuring point at a predetermined incidence angle from a plurality of incidence directions set at predetermined angular intervals centering on a normal line established at a measuring point on a thin film sample, Among the polarization components included in the reflected light of the monochromatic light, the reflected light intensity of the polarization component orthogonal to the polarization direction of the irradiation light is detected according to the incident direction, The azimuth direction Φ _A of the optical axis at the measuring point based on the measured incidence direction is the minimum value interspersed between two maximums of the maximum peaks among the incidence directions indicating the minimum value of the reflected light intensity or the two maximums between two maximums of the intermediate peaks measured. To determine, The minimum value interposed between the maximum value at which the reflected light intensity becomes the maximum peak and the maximum value which is the intermediate peak adjacent to the maximum value is determined by the measured incidence direction Φ _B or the maximum value that becomes the maximum peak is determined by the measured incidence direction. A method for measuring optical anisotropy parameter, characterized in that the polar angle direction θ of the optical axis at the measuring point is determined by equation (2) or (3) based on angles Φ _C and Φ _D.

Φ _B : When Φ _A = 0, the incident direction in which the minimum value interposed between the maximum value at the maximum peak and the maximum value at the intermediate peak was measured. When Φ _C : Φ _A = 0, the incident direction in which the maximum value that becomes the maximum peak is measured When Φ _D : Φ _A = 0, the incident direction in which the maximum value that becomes the maximum peak is measured θ: angle (inclined angle) in the polar angle direction of the optical axis from the substrate plane μ: +/- (“+” when the reflection intensity of P-polarized light is incident to S-polarized light, “-” when the reflection intensity of S-polarized light is incident to P-polarized light) φ ₀ : incident angle of the thin film φ ₂ : angle of light when entering the substrate N ₂ : refractive index of the substrate ε ₀ : normal photo permittivity of thin film sample The method of claim 1, And rotating the sample about the normal line to irradiate monochromatic light of P-polarized light or S-polarized light with respect to the measuring points from a plurality of incidence directions at a predetermined incident angle. The method of claim 1, The monochromatic light of the P-polarized light or the S-polarized light is irradiated from a plurality of light emitting parts arranged at predetermined angular intervals around the normal line. 4. The method according to any one of claims 1 to 3, An optical anisotropy parameter measuring method comprising measuring anisotropy of an optical axis with respect to a plurality of measuring points by moving a thin film sample. The method of claim 1, A first angle at which the minimum value interposed between two maximum values at which the incident direction of monochromatic light of P-polarized light or S-polarized light incident at predetermined angular intervals centers on the normal line is the maximum peak is expected, and the maximum value is the maximum peak. And a plurality of predetermined values are set at predetermined angular intervals each at a predetermined angle range centering on the second angle at which the minimum value interposed between the maximum value and the maximum value at the intermediate peak, the maximum value at the maximum peak, or the maximum value at the intermediate peak is expected to exist. Optical anisotropy parameter measuring method, characterized in that. An optical anisotropy parameter measuring method for measuring azimuth and polar directions of an optical axis serving as anisotropic parameters of a thin film sample, Monochromatic light of P-polarized light or S-polarized light is irradiated to the measurement area at a predetermined incidence angle from a plurality of incidence directions set at predetermined angular intervals centered on a normal line established at the center of the measurement area on the thin film sample, By detecting the reflected light intensity distribution of the polarization component orthogonal to the polarization direction of the irradiation light among the polarization components included in the reflected light of the monochromatic light, the respective reflected light intensities are detected two-dimensionally according to the incidence direction for each measurement point present in the measurement region, For each measuring point, the optical at the measuring point is based on the measured incident direction on which the minimum value interposed between two maximum values of the maximum peak among the incidence directions where the reflected light intensity is the minimum value or the minimum value interspersed between two maximum values of the intermediate peak is measured. Determine the azimuth direction Φ _A of the axis, The minimum value interposed between the maximum value at which the reflected light intensity becomes the maximum peak and the maximum value which is the intermediate peak adjacent to the maximum value is determined by the measured incidence direction Φ _B or the maximum value that becomes the maximum peak is determined by the measured incidence direction. A method for measuring optical anisotropy parameter, characterized in that the polar angle direction θ of the optical axis at the measuring point is determined by equation (2) or (3) based on angles Φ _C and Φ _D.

_B Φ: Φ _A = when 0, the minimum value is sandwiched between the maximum value is a maximum value and the intermediate peak to the maximum peak measured incident direction When Φ _C : Φ _A = 0, the incident direction in which the maximum value that becomes the maximum peak is measured When Φ _D : Φ _A = 0, the incident direction in which the maximum value that becomes the maximum peak is measured θ: angle (inclined angle) in the polar angle direction of the optical axis from the substrate plane μ: +/- (“+” when the reflection intensity of P-polarized light is incident to S-polarized light, “-” when the reflection intensity of S-polarized light is incident to P-polarized light) φ ₀ : incident angle of the thin film φ ₂ : angle of light when entering the substrate N ₂ : refractive index of the substrate ε ₀ : normal photo permittivity of thin film sample The method of claim 1, A method of measuring the optical anisotropy parameter, wherein the main dielectric constant and film thickness of the anisotropic thin film serving as optical anisotropy parameters are obtained by measuring with an ellipsometer or reflectometer from at least two directions based on the determined azimuth direction. An optically anisotropic parameter measuring apparatus for measuring azimuth and polar directions of an optical axis serving as anisotropic parameters of a thin film sample, A light emitting optical system for irradiating monochromatic light of P-polarized light or S-polarized light with respect to the measuring point at a predetermined incident angle from a plurality of incident directions set at predetermined angular intervals centered on a normal line placed on the measuring point on the thin film sample; A light receiving optical system for detecting the reflected light intensity of the polarization component orthogonal to the polarization direction of the irradiation light among the polarization components included in the reflected light of the monochromatic light according to the incident direction; And The azimuth direction Φ of the optical axis at the measurement point based on the incident direction in which the minimum value interspersed between two maximums of the maximum peaks among the incident directions in which the reflected light intensity represents the minimum value or the two maximums between two maximums of the intermediate peak is measured At the same time, _A is determined while the minimum value interposed between the maximum value at which the reflected light intensity becomes the maximum peak and the maximum value which is the intermediate peak adjacent to the maximum value is measured, and the maximum value at which the incident direction Φ _B or the maximum peak is measured is measured. An arithmetic processing device for determining the polar angle direction θ of the optical axis at the measurement point by equation (2) or equation (3) based on angles Φ _C , Φ _D determined by the determined incident direction; Optical anisotropy parameter measuring apparatus comprising a.

_B Φ: Φ _A = when 0, the minimum value is sandwiched between the maximum value is a maximum value and the intermediate peak to the maximum peak measured incident direction When Φ _C : Φ _A = 0, the incident direction in which the maximum value that becomes the maximum peak is measured When Φ _D : Φ _A = 0, the incident direction in which the maximum value that becomes the maximum peak is measured θ: angle (inclined angle) in the polar angle direction of the optical axis from the substrate plane μ: +/- (“+” when the reflection intensity of P-polarized light is incident to S-polarized light, “-” when the reflection intensity of S-polarized light is incident to P-polarized light) φ ₀ : incident angle of the thin film φ ₂ : angle of light when entering the substrate N ₂ : refractive index of the substrate ε ₀ : normal photo permittivity of thin film sample 9. The method of claim 8, Optically anisotropic parameter measuring apparatus characterized in that the sample is disposed rotatably around the normal. 9. The method of claim 8, And a plurality of sets of the light emitting optical system and the light receiving optical system are arranged around the normal line at predetermined angular intervals. 9. The method of claim 8, An optically anisotropic parameter measuring apparatus comprising a table for moving a thin film sample to measure anisotropy of an optical axis with respect to a plurality of measuring points. 9. The method of claim 8, The maximum value at which the incident direction of monochromatic light of P-polarized light or S-polarized light incident at predetermined angular intervals centered on the normal line is the first angle and the maximum peak expected to exist between two maximum values that become maximum peaks. A plurality of settings at predetermined angular intervals, each at a predetermined angle range, centered on a second angle at which any one of the minimum value, the maximum value between the maximum peak, and the maximum value between the intermediate peaks, and the maximum value between the maximum peaks and the intermediate peak, respectively, are expected to exist. Optical anisotropy parameter measuring device, characterized in that made. An optically anisotropic parameter measuring apparatus for measuring azimuth and polar directions of an optical axis serving as anisotropic parameters of a thin film sample, A light-emitting optical system for irradiating monochromatic light of P-polarized light or S-polarized light to a predetermined incident angle from a plurality of incidence directions set at predetermined angular intervals centered on a normal line established at the center of the measured area on the thin film sample at a predetermined incident angle; A two-dimensional light receiving element for detecting the respective reflected light intensity in accordance with the incident direction by measuring the reflected light intensity distribution of the polarization component orthogonal to the polarization direction of the irradiation light of the polarization components included in the reflected light of the monochromatic light according to the incident direction A light receiving optical system having; And For each measuring point, the optical at the measuring point is based on the measured incident direction on which the minimum value interposed between two maximum values of the maximum peak among the incidence directions where the reflected light intensity is the minimum value or the minimum value interspersed between two maximum values of the intermediate peak is measured. While determining the azimuth direction Φ _A of the axis, the minimum value interposed between the maximum value at which the reflected light intensity becomes the maximum peak and the maximum value at the intermediate peak adjacent to the maximum value becomes the measured incident direction Φ _B or the maximum peak. An arithmetic processing apparatus for determining the polar angle direction θ of the optical axis at the measurement point by equation (2) or equation (3) based on angles Φ _C , Φ _D determined by the measured incident direction; Optical anisotropy parameter measuring apparatus comprising a.

_B Φ: Φ _A = when 0, the minimum value is sandwiched between the maximum value is a maximum value and the intermediate peak to the maximum peak measured incident direction When Φ _C : Φ _A = 0, the incident direction in which the maximum value that becomes the maximum peak is measured When Φ _D : Φ _A = 0, the incident direction in which the maximum value that becomes the maximum peak is measured θ: angle (inclined angle) in the polar angle direction of the optical axis from the substrate plane μ: +/- (“+” when the reflection intensity of P-polarized light is incident to S-polarized light, “-” when the reflection intensity of S-polarized light is incident to P-polarized light) φ ₀ : incident angle of the thin film φ ₂ : angle of light when entering the substrate N ₂ : refractive index of the substrate ε ₀ : normal photo permittivity of thin film sample

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