JP2007212330A - Optical anisotropic parameter measuring method and measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and instrument for measuring the direction of an optical axis of an optical anisotropic thin film, and its size and film thickness at a high speed with high accuracy, and further, performing distribution measurement by means of a two-dimensional light receiving element. <P>SOLUTION: While a turn table 6 mounted with light emitting and light receiving optical systems 4 and 5 is turned centering on a normal line R set up at a measurement point M, monochromatic light of P polarization is applied thereto at prescribed incident angles in a plurality of incident directions set at prescribed angular intervals to detect the intensity of reflected light of S polarization included in reflected light of the monochromatic light. An azimuthal angle direction Φ<SB>A</SB>of an optical axis OX at the measurement point M is determined based on an incident direction ν<SB>1</SB>in which a local minimum value V<SB>1</SB>is measured, with the minimum value V<SB>1</SB>interposed between two local maximum values Λ<SB>1</SB>and Λ<SB>2</SB>being maximum peaks among incident directions in which the reflected light intensity shows local minimum values. A polar angle direction θ can be determined, based on an incident direction in which a local minimum value V<SB>3</SB>is measured, with the minimum value V<SB>3</SB>interposed between the local maximum value Λ<SB>1</SB>being a maximum peak and a local maximum value Λ<SB>3</SB>being an intermediate peak adjoining thereto. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical anisotropy parameter measuring method and measuring apparatus for measuring the anisotropy of the optical axis of a thin film sample, and is particularly suitable for use in inspection of a liquid crystal alignment film.

  The liquid crystal display has a back glass substrate with a transparent electrode and alignment film laminated on the surface, and a front glass substrate with a color filter, transparent electrode and alignment film laminated on the surface, with the alignment films facing each other through a spacer, The liquid crystal is sealed in a gap between the alignment films, and a polarizing filter is laminated on both the front and back sides.

Here, in order for the liquid crystal display to operate normally, the liquid crystal molecules must be uniformly arranged in the same direction, and the alignment film determines the directionality of the liquid crystal molecules.
This alignment film can align the liquid crystal molecules because it has uniaxial optical anisotropy, and the alignment film has uniform uniaxial optical anisotropy over the entire surface. If this is the case, defects in the liquid crystal display are unlikely to occur, and if there are non-uniform portions of optical anisotropy, the direction of the liquid crystal molecules is disturbed, resulting in a defective liquid crystal display.
That is, the quality of the alignment film directly affects the quality of the liquid crystal display, and if there is a defect in the alignment film, the directionality of the liquid crystal molecules is disturbed, resulting in a defect 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 having a stable quality is used, the yield of the liquid crystal display is improved and the production efficiency is improved.
For this reason, by measuring the azimuth angle direction, polar angle direction, film thickness, etc. of the optical axis as an anisotropy parameter for the alignment film, and evaluating the optical anisotropy of the alignment film, A method for inspecting the presence or absence has been proposed.

  The most common method is to use an ellipsometer, which can be measured fairly accurately, but the measurement time per measurement point is as long as 2 minutes, and the anisotropy of one alignment film When evaluating a total of 10,000 points of 100 × 100, it takes about two weeks by simple calculation, so it is impossible to put 100% inspection on the production line.

This is because the measurement point is irradiated with P-polarized light or S-polarized monochromatic light at a predetermined incident angle from a plurality of incident directions set at predetermined angular intervals with the normal line set at the measurement point of the thin film sample as the center. By measuring the reflected light intensity of the polarized light component included in the reflected light and orthogonal to the polarization direction of the irradiated light, the change in the reflected light intensity according to the incident direction is detected, thereby detecting an optical difference. The azimuth angle direction, polar angle direction, and film thickness, which are parameters of the isotropic thin film, are to be calculated.
JP 2001-272308 A

However, according to this, in order to obtain the parameters of the optically anisotropic thin film, this method has a problem that it takes time because it is necessary to measure in all directions.
In addition, since the measurement requires an absolute amount of reflected light intensity, the measurement accuracy is affected by the influence of external factors such as the linearity of the sensitivity of the light receiving element and the dynamic range, and the error is likely to increase. There is a problem that it is difficult to improve accuracy.
Furthermore, since it is necessary to calculate more than six parameters of the direction and size of the principal dielectric constant axis, the film thickness, and the normalization constant at the same time by the nonlinear least square method, the solution converged by the local minimum is calculated. There is a problem that not only there is a possibility that the calculation will occur, but a huge amount of time is required for the calculation.

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

  In order to solve this problem, the present invention is an optical anisotropy parameter measuring apparatus for measuring an azimuth direction and a polar angle direction of an optical axis that is an anisotropy parameter of a thin film sample, and is placed on a stage. A light-emitting optical system that irradiates a measurement point on a thin film sample with P-polarized light or S-polarized monochromatic light at a predetermined incident angle, and a polarization component included in the reflected light that is orthogonal to the polarization direction of the irradiated light. A light receiving optical system that detects the reflected light intensity of the polarized light component according to the incident direction, and the light emitting optical system and the light receiving optical system are rotated around a normal line set at a measurement point and set at predetermined angular intervals. A rotary table that irradiates the measurement point with light from a plurality of incident directions, and a minimum value or an intermediate peak that is sandwiched between two maximum values that are the maximum peak among the incident directions in which the reflected light intensity has a minimum value. Pole between two maxima The azimuth direction of the optical axis at the measurement point is determined based on the incident direction in which the value is measured, and the reflected light intensity is sandwiched between the maximum value at which the reflected light intensity reaches the maximum peak and the maximum value at the intermediate peak adjacent thereto. And an arithmetic processing unit that determines the polar angle direction of the optical axis at the measurement point based on the incident direction in which the minimum value is measured or the incident direction in which the maximum value that is the maximum peak is measured. It is said.

According to the present invention, first, a thin film sample is placed on a stage, and is set at predetermined angular intervals while rotating the light-emitting optical system and the light-receiving optical system with a rotary table that rotates around the normal line set at the measurement point. The P-polarized light or S-polarized light is irradiated to the measurement point from a plurality of incident directions at a predetermined incident angle, and the polarization component included in the reflected light is orthogonal to the polarization direction of the irradiated light. By measuring the reflected light intensity of the component, a change in the reflected light intensity corresponding to the incident direction is detected.
When the incident direction is changed between 0 ° and 360 °, the measured value of the reflected light intensity of the thin film sample having optical anisotropy becomes an intermediate peak while the two maximum values that are the maximum peaks are adjacent to each other. Two maximum values are adjacent to each other, and a waveform having four minimum values between the maximum values is obtained.

Here, the angle in 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 direction in which the minimum value sandwiched between the two maximum values having the maximum peak is measured. The direction is determined as the azimuth angle direction, and the angle is set as the azimuth angle direction Φ _A = 0 at the measurement point.
Note that this direction is 180 ° away from the direction in which the minimum value sandwiched between the two maximum values serving as the intermediate peak is measured, so the minimum value sandwiched between the two maximum values serving as the intermediate peak is measured. Can also be identified from the direction.

Φ_Ａ：最大ピークとなる二つの極大値に挟まれた極小値が測定された入射方向（＝方位角方向＝０）
Φ_Ｂ：最大ピークとなる極大値と中間ピークとなる極大値に挟まれた極小値が測定された入射方向
Φ_Ｃ：最大ピークとなる極大値が測定された入射方向
Φ_Ｄ：最大ピークとなる極大値が測定された入射方向
θ ：基板平面からの光学軸の極角方向の角度（傾斜角）
μ ：＋／−（Ｓ偏光入射に対するＰ偏光の反射強度のとき「＋」、Ｐ偏光入射に対するＳ偏光の反射強度のとき「−」）
φ_０：薄膜への入射角度
φ_２：基板へ抜けた時の光の角度
Ｎ_２：基板の屈折率
ε_０：薄膜試料の常光誘電率 Next, the angle of the optical axis of the thin film sample in the polar angle direction, that is, the inclination angle of the optical axis with respect to the substrate plane can be calculated by the formula (2) or the formula (3).
Here, in Equations (2) and (3), variables other than the angle θ in the polar angle direction are all known or measured values. Therefore, according to Equation (2), the maximum value and the intermediate peak that are the maximum peaks It can be calculated by detecting the angle at which the minimum value sandwiched between the maximum values is measured, and by detecting the angle at which the maximum value at which the maximum peak is measured is detected according to Equation (3).

Φ _A : Incident direction (= azimuth direction = 0) in which a minimum value sandwiched between two maximum values having a maximum peak is measured
Φ _B : Incident direction in which a minimum value sandwiched between a maximum value serving as a maximum peak and a maximum value serving as an intermediate peak is measured Φ _C : Incident direction in which a maximum value serving as a maximum peak is measured Φ _D : Maximum peak Incident direction θ in which the maximum value was measured: Angle of the optical axis from the substrate plane in the polar angle direction (tilt angle)
μ: +/− (“+” when the reflection intensity of P-polarized light is incident on S-polarized light, “−” when the reflection intensity of S-polarized light is incident on P-polarized light)
φ ₀ : incident angle to thin film φ ₂ : angle of light when it passes through the substrate N ₂ : refractive index of substrate ε ₀ : ordinary light dielectric constant of thin film sample

  Further, P-polarized light or S-polarized monochromatic light is irradiated at a predetermined incident angle to an arbitrary measurement area on the thin film sample, and the polarization component included in the reflected light is orthogonal to the polarization direction of the irradiated light. By detecting the reflected light intensity distribution of the polarization component two-dimensionally, by detecting the reflected light intensity according to the incident direction at each measurement point in the measurement area, the azimuth angle direction is individually measured for a plurality of measurement points. The polar angle direction can be calculated.

When a liquid crystal alignment film is used as a thin film sample, for example, the optical axis is aligned by rubbing, and the extreme value that minimizes the reflected light intensity when incident from the vicinity of the rubbing direction and the direction orthogonal thereto is obtained. Exists.
In addition, the angle (direction) where the maximum value at which the reflected light intensity becomes the maximum peak or the intermediate peak exists depends on the polar angle direction, and when manufacturing a liquid crystal alignment film, it is empirically approximated by the rubbing intensity (pressure). Since the polar angle direction is controlled, it can be specified from the formula (3) based on the polar angle direction.
Therefore, centering on the angle (direction) where light is incident in a predetermined angle range centering on the rubbing direction and the direction orthogonal to the rubbing direction, or the maximum value where the rubbing direction and reflected light intensity has the maximum peak exists. The measurement range can be narrowed by making light incident on the lens within a predetermined angle range.
Note that this angle range is limited to about ± 20 ° if there is little variation based on empirically measured statistical variation in the azimuthal direction, etc., in the liquid crystal alignment film production line and the like. If the variation is large, the range may be expanded to about ± 45 °.

Thus, the azimuth angle direction and the polar angle direction of the optical axis can be determined as long as the incident direction of the minimum value and maximum value of the reflected light is known, and the thin film sample is measured at the measurement points at which these values are known. When measuring the thickness t of the anisotropic layer, the ordinary light dielectric constant ε ₀ , and the extraordinary light dielectric constant ε _e , it is only necessary to measure in two or three directions with an ellipsometer or a reflectometer. These optical anisotropy parameters can be measured.

  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 places a thin film sample on a stage and sets the normal line set at the measurement point. While rotating the light-emitting optical system and the light-receiving optical system with a rotating table that rotates around, a monochromatic light of P-polarized light or S-polarized light is irradiated to a measurement point at a predetermined incident angle, and among the polarization components included in the reflected light, The reflected light intensity of the polarization component orthogonal to the polarization direction of the irradiated light is detected according to the incident direction, and the minimum value sandwiched between the two maximum values of the maximum peak among the incident directions indicating the minimum value of the reflected light intensity. Determine the azimuth direction of the optical axis at the measurement point based on the incident direction in which the minimum value sandwiched between the two maximum values or the intermediate peak is measured, and the maximum value at which the reflected light intensity becomes the maximum peak The pole that becomes the intermediate peak adjacent to this Incident direction minimum value sandwiched value was measured, or were to determine the polar angle direction of the optical axis at the measurement points based on the direction of incidence maximum value with the maximum peak was determined.

  FIG. 1 is an explanatory view showing an example of an optical anisotropy parameter measuring apparatus according to the present invention, and FIG. 2 shows a relationship between an incident direction showing a minimum value of reflected light intensity, an azimuth angle direction and a polar angle direction of an optical axis. 3 is a conceptual diagram, FIG. 3 is a graph showing the measurement result of reflected light intensity, FIG. 4 is an explanatory diagram showing another optical anisotropy parameter measuring device, and FIG. 5 is a transition of the position of each measurement point with the rotation of the thin film sample. FIG. 6 is an explanatory diagram showing the measurement result of the inclination angle distribution.

The optical anisotropy parameter measuring apparatus 1 of this example is provided integrally with a rubbing apparatus 10 that forms an alignment film (thin film sample) 3 on the surface of a substrate placed on a stage 2, and immediately after the rubbing process is completed. , and to be able to measure the azimuthal direction [Phi _a and polar angle direction θ of the optical axis OX of the optical anisotropy parameter of the alignment film 3.
The rubbing device 10 includes moving frames F ₁ and F ₂ including the measuring device 1 and the rubbing roller 9, and includes the rubbing roller 9 in a state where the moving frame F ₁ including the measuring device ₁ is retracted. while moving the moving frame F ₂ performs rubbing, after rubbing ends, in a state of being retracted to move the frame F ₂ with a rubbing roller 9, is advanced to move frames F ₁ provided with a measuring device 1 to a predetermined position To measure the anisotropic parameter.

  The measuring apparatus 1 includes a light-emitting optical system 4 that irradiates a measurement point M on the alignment film 3 with P-polarized light or S-polarized monochromatic light at a predetermined incident angle, and irradiation of polarization components included in the reflected light. The light-receiving optical system 5 that detects the reflected light intensity of the polarization component orthogonal to the polarization direction of the light according to the incident direction, and the light-emitting optical system 4 and the light-receiving optical system 5 around the normal line R set at the measurement point M A rotating table 6 that rotates and irradiates the measurement point M with light from a plurality of incident directions set at predetermined angular intervals, and an arithmetic processing unit that determines the polar angle direction of the optical axis at the measurement point M based on the measurement result 7.

The optical axis 4x of the light emitting optical system 4 and the optical axis 5x of the light receiving optical system 5 are designed to be equiangularly crossed at the measurement point M and are attached to the rotary table 6 rotated by the motor 11.
The rotary table 6 is arranged so that the rotation axis 6x thereof coincides with the normal line R set at the measurement point M, and the tilt adjustment mechanism 12, the light emitting optical system 4 and the tilt adjustment mechanism 12 for adjusting the inclination of the rotation axis 6x with respect to the normal line R The Z table (height adjustment mechanism) 13 for matching the height of the intersection of the optical axes 4x and 5x of the light receiving optical system 5 with the alignment film 3, the intersection of the optical axes 4x and 5x of the light emitting optical system 4 and the light receiving optical system 5 An XY table (XY moving mechanism) 14 that matches the position with an arbitrary measurement point M is provided.

The light emitting optical system 4 is arranged such that a He—Ne laser 21 having a wavelength of 632.8 nm and a light intensity of 25 mW has an incident angle (60 ° in this example) near the Brewster angle with high measurement accuracy. A polarizer 22 composed of a Glan-Thompson prism (extinction ratio 10 ⁻⁶ ) that transmits P-polarized light is disposed along the axis 4x.

The light receiving optical system 5 includes a pinhole slit 23 for erasing light due to back surface reflection from the alignment film 3 along the optical axis 5x of light irradiated from the laser 21 and reflected by the alignment film 3, and S-polarized light. An analyzer 24 composed of a Glan-Thompson prism (extinction ratio 10 ⁻⁶ ) to be transmitted, a wavelength selection filter 25, and a photomultiplier tube 26 are arranged, and a detection signal of the photomultiplier tube 26 is output to the arithmetic processing unit 7. It has come to be.

Further, at the center of the rotary table 6, a tilt detection imaging device 15 having an optical axis arranged coaxially with the rotary shaft 6x is arranged.
The imaging device 15 includes a light source device (not shown) that coaxially reflects the laser light toward the stage 2 so that the laser light reflected by the alignment film 3 can be imaged.
Thereby, when the rotating shaft 6x of the rotary table 6 is not inclined with respect to the normal line R, the light receiving point of the reflected light does not move even if the rotary table 6 is rotated, so that it can be determined that there is no tilt. Further, when the rotary shaft 6x of the rotary table 6 is inclined with respect to the normal line R, a tilt is generated when the rotary table 6 is rotated, and the light receiving point of the reflected light is not constant and a locus of a closed curve is drawn. Therefore, the tilt amount can be detected from this locus.

The arithmetic processing unit 7 inputs a detection signal output from the photomultiplier tube 26 every time the turntable 6 is rotated by a predetermined angle, and stores the relationship between the rotation angle (incident direction) and the reflected light intensity.
It reflected light intensity is detected when changing the direction of incidence up to 0 to 360 ° for the alignment film 3 having optical anisotropy changes are generally, as shown in the graph G ₁ of FIG. 3, the maximum peak two The waveform has four local maximum values Λ ₁ and Λ ₂ and two local maximum values Λ ₃ and Λ ₄ that are intermediate peaks, and four local minimum values V _{1 to} V ₄ .
That is, as shown in FIG. 2, the minimum values V ₁ and V ₂ are measured when entering from the longitudinal direction of the optical axis OX in a plan view, and are orthogonal to the optical axis in the longitudinal section including the optical axis OX. The minimum values V ₃ and V ₄ are measured when the light enters from the direction in which the light enters.

Of the incident directions ν _{1 to} ν ₄ indicating the minimum value of the reflected light intensity, the minimum value V ₁ sandwiched between the two maximum values Λ ₁ and Λ ₂ , which is the maximum peak, is measured in the incident direction ν ₁ . azimuthal direction [Phi _a of the optical axis are determined at the measurement point based. That is, the incident direction ν _{1 is set} to the azimuth direction Φ _A = 0.
Next, an incident direction ν ₃ in which a minimum value V ₃ sandwiched between a maximum value Λ ₁ at which the reflected light intensity becomes a maximum peak and a maximum value Λ ₃ at an intermediate peak adjacent thereto is measured, and the reflected light intensity has a maximum peak. The incident direction ν ₄ in which the minimum value V ₄ sandwiched between the maximum value Λ ₂ and the maximum value Λ ₄ adjacent to the maximum value Λ ₂ is measured, or the maximum value Λ ₁ or Λ _{2 that} is the maximum peak is Based on the measured incident direction λ ₁ or λ ₂ , the polar angle direction θ of the optical axis at the measurement point is determined.
In this case, when calculating based on Equation (2),
Φ _B = ν ₃ −ν ₁ = ν ₄ −ν ₁
And when calculating based on equation (3):
| Φ _C | = | Φ _D | = | λ ₁ −λ ₂ | / 2 = | λ ₃ −λ ₄ | / 2
And it is sufficient.

Thereafter, since the azimuth direction Φ _A and the polar angle direction θ of the optical axis OX of the alignment film 3 are known, if measurement is performed from any two directions using an ellipsometer or a reflectometer, the main dielectric constant of the thin film sample is increased. Thickness and thickness can be determined.

The above is an example of the configuration of the device of the present invention. Next, the method of the present invention will be described.
As a thin film sample, soluble polyimide was applied on the glass substrate 8 and heated at 200 ° C.
The glass substrate 8 was placed on the stage 2, and the rubbing device 10 was advanced onto the stage 2 with the measuring device 1 retracted from the stage 2, and rubbing was performed with the rubbing roller 9.

After the rubbing is completed, the rubbing device 10 is retracted, the measuring device 1 is advanced, and the Z table 13 and the XY table 14 are set so that the intersection position of the optical axes 4x and 5x coincides with the preset measurement point. Adjustment and XY position adjustment.
Thereafter, the rotary table 6 is rotated, the amount of movement is detected by the imaging device 15, the height adjustment is performed by the tilt adjustment table 11, and then the height is adjusted again by the Z table 13 so that the reflected light intensity becomes maximum. went.

Thereafter, the intensity of reflected light of S-polarized light with respect to the incident direction was measured while rotating the rotary table 6.
Alignment film 3 rubbing, the azimuth angle direction [Phi _A can be expected that the rubbing direction (X direction) and are substantially parallel, it is possible to expect to be in a position where the polar angle direction θ is substantially perpendicular to this, the present embodiment Then, the reflected light intensity was measured at intervals of 2 ° in a range of ± 20 ° centered on the rubbing direction and ± 20 ° centered on the direction orthogonal to the rubbing direction (Y direction).
Note that this measurement range is an arbitrary angle such as ± 45 ° or ± 30 °, taking into account the deviation between the azimuth direction where the optical axis can be predicted and the actual azimuth direction measured empirically. The range may be set.

Enlarged graphs G ₂ and G _{3 in} FIG. 3 are changes in reflected light intensity in respective measurement ranges centered on the X direction and the Y direction.
From this measurement data, the azimuth angle direction Φ _A and the polar angle direction θ of the optical axis OX were obtained.
When obtaining the polar angle direction θ, the ordinary light dielectric constant of the formula (2) was set as the dielectric constant ε ₀ = 3.00 of the polyimide film before rubbing.
Performs fitting calculation with respect to the measurement results of the graph G _2, was calculated azimuth [nu ₁ which received light intensity becomes minimum was ν _{1 =} 0.4 °. Therefore, the azimuth angle direction Φ _A of the optical axis OX is 0 _. It can be seen that it is tilted 4 °.
Further, fitting calculation is performed on the measurement result of the graph G ₃ to calculate the direction ν _{3 at} which the received light intensity becomes the minimum, Φ _B = ν ₃ −ν ₁ , ordinary light dielectric constant ε ₀ = 3.00 (before rubbing) When the polar angle direction θ was calculated based on the formula (2) as the dielectric constant of the polyimide film, θ = 22.5 °.
At this time, the measurement time at one measurement point was about 2 seconds.

Based on this result, an ellipsometer was used to measure in two directions, the azimuth direction of the optical axis of the alignment film 3 and the direction orthogonal thereto, and it was found that the ordinary optical dielectric constant ε ₀ = 2.79 and the extraordinary optical dielectric constant ε. _e = 3.44 and the thickness t of the anisotropic layer was 11 nm. When the polar angle direction θ was recalculated from the value of the ordinary light permittivity ε ₀ , it was 24.5 °.
At this time, even if the time to measure with an ellipsometer was included, the measurement time was about 4 seconds per measurement point, and a result equivalent to the conventional method could be measured at high speed.

FIG. 4 shows another embodiment of the optical anisotropy parameter measuring apparatus, and the parts common to FIG.
In the optical anisotropy parameter measuring device 31 of this example, the light-emitting optical system 4 is provided with a xenon lamp 32, and along the optical axis 4x, a pinhole slit 34 at the condensing point of the reflecting mirror 33, and its transmission. A collimating lens 35 that collimates light, an interference filter 36, and a polarizer 22 that transmits P-polarized light are disposed.
At this time, the interference filter 35 was selected to have a center wavelength of 450 nm and a full width at half maximum of 2 nm, the beam diameter irradiated to the alignment film 3 was set to 10 mm ² , and the incident angle was set to 60 ° near the Brewster angle.

The light receiving optical system 5 includes an analyzer 24 that transmits S-polarized light, a wavelength selection filter 37, and a two-dimensional CCD camera 38 along the optical axis 5x.
Thereby, the reflected light intensity from the plurality of measurement points Mij included in the measurement area A of 10 mm ² irradiated on the alignment film 3 can be measured simultaneously.

In the same manner as in Example 1, rubbing was performed with the rubbing apparatus 10. In this example, the rubbing was performed so that the rubbing strength was higher on the right side than on the left side of the alignment film 3 during rubbing.
The rubbing device 10 is retracted, the measuring device 1 is advanced, the height adjustment and the XY position adjustment are performed with the Z table 13 and the XY table 14, the tilt is adjusted, the rotation table 6 is rotated, and the reflection with respect to the incident direction is performed. Two-dimensional distribution measurement of light intensity was performed.

FIG. 5A shows measurement points Mij (i, j = 1 to 10) in the measurement area A before rotation.
FIG. 5B shows an image rotated with the rotation of the turntable 6. If each measurement point Mij is represented by polar coordinates Mij = (r _n , α _m ), the turntable 6 is rotated by an angle γ. The position of Mij 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).

  In this way, with respect to a total of 100 measurement points Mij, as in Example 1, ± 20 ° centered on the rubbing direction (X direction) and ± 20 ° centered on the direction orthogonal to this (Y direction). The reflected light intensity was measured at intervals of 2 ° in the range, and the distribution in the polar angle direction θ was obtained using the equation (7). At this time, the measurement time of 100 measurement points was 2 seconds.

Based on this result, for each measurement point Mij of the sample, the azimuthal direction [Phi _A of the optical axis OX, in two directions in the direction perpendicular thereto, was measured by an ellipsometer, ordinary dielectric constant epsilon _0, abnormal light dielectric The rate ε _e and the thickness t of the anisotropic layer were measured.
Figure 6 shows a recalculated distribution of polar angle direction θ from the measured ordinary value of the dielectric constant epsilon _0.
According to this, the distribution was 30 to 34 ° on the right side and 27 to 29 ° on the left side.
In addition, when 10 × 10 = 100 points were measured by the conventional method in the same alignment film 3 polar angle direction θ, the distribution on the right side was 30 to 34 ° and the left side was 27 to 29 °, and the measurement time was about 100 points. 100 minutes, and in the present invention, the measurement time for 100 measurement points was about 6 seconds even when the time for measurement with an ellipsometer was included.
Therefore, the result equivalent to the conventional method could be measured at a very high speed.

In the above description, the case where the optical anisotropy parameter measuring apparatus 1 is provided integrally with the rubbing apparatus 10 that forms the alignment film (thin film sample) 3 on the substrate surface placed on the stage 2 has been described. However, the present example is not limited to this, and any device that imparts optical anisotropy to a thin film sample may be provided integrally with a photo-alignment processing device or other optical anisotropy imparting device.
In this case, similarly to the rubbing apparatus 10, the stage 2 of the measuring apparatus 1 may be used also as the stage of the optical anisotropy imparting apparatus.

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

Explanatory drawing which shows an example of the optical anisotropy parameter measuring apparatus which concerns on this invention. The conceptual diagram which shows the relationship between the azimuth | direction angle direction and polar angle direction of an optical axis. The graph which shows the measurement result. Explanatory drawing which shows another optical anisotropy parameter measuring apparatus. Explanatory drawing which shows transition of the position of each measurement point accompanying rotation of a thin film sample. Explanatory drawing which shows polar angle direction distribution.

Explanation of symbols

1, 31 Optical anisotropy parameter measuring device 2 Stage 3 Alignment film (thin film sample)
OX optical axis
Φ _A Azimuth angle direction θ Polar angle direction M Measuring point R Normal 4 Light emitting optical system 5 Light receiving optical system 6 Rotary table 7 Arithmetic processing device

Claims (12)

An optical anisotropy parameter measurement method for measuring an azimuth angle direction and a polar angle direction of an optical axis as an anisotropy parameter of a thin film sample,
A light emitting optical system that irradiates a measurement point on a thin film sample placed on a stage with P-polarized light or S-polarized monochromatic light at a predetermined incident angle, and polarization of irradiated light among polarized components included in the reflected light. The light receiving optical system that detects the reflected light intensity of the polarization component orthogonal to the direction according to the incident direction is set at predetermined angular intervals while rotating on a rotary table that rotates around the normal line set at the measurement point. Detect reflected light intensity for multiple incident directions,
Among the incident directions indicating the minimum value of the reflected light intensity, the minimum value sandwiched between the two maximum values serving as the maximum peak or the minimum value sandwiched between the two maximum values serving as the intermediate peak is measured in the incident direction. Based on the azimuth direction of the optical axis at the measurement point based on,
In the incident direction in which the minimum value sandwiched between the maximum value where the reflected light intensity is the maximum peak and the maximum value which is adjacent to the maximum value is measured, or in the incident direction where the maximum value which is the maximum peak is measured A method for measuring an optical anisotropy parameter, comprising: determining a polar angle direction of an optical axis at the measurement point based on the measurement result.   The optical difference according to claim 1, wherein the rotating table is moved in the X and Y directions so that the irradiation light of the light emitting optical system is sequentially irradiated to a plurality of measurement points, and the anisotropy of the optical axis at each measurement point is measured. Method for measuring isotropic parameters.   2. The optical device according to claim 1, wherein the intersection of the optical axes of the light-emitting optical system and the light-receiving optical system is made to coincide with the height of the thin film sample by raising and lowering the rotary table before detecting the reflected light intensity with respect to each incident direction. Anisotropy parameter measurement method.   The optical anisotropy parameter measurement method according to claim 1, wherein the tilt adjustment of the rotary table is performed before detecting the reflected light intensity with respect to each incident direction.   The first angle at which the incident direction of monochromatic light of P-polarized light or S-polarized light that is incident at a predetermined angular interval centered on the normal line is expected to have a minimum value sandwiched between two maximum values that have the maximum peak. Then, centering on the second angle where there is a local minimum value between the local maximum value that is the maximum peak and the local maximum value that is the intermediate peak, the local maximum value that is the maximum peak, or the local maximum value that is the intermediate peak, The method for measuring an optical anisotropy parameter according to claim 1, wherein a plurality of the predetermined angle ranges are set at predetermined angular intervals. An optical anisotropy parameter measurement method for measuring an azimuth angle direction and a polar angle direction of an optical axis as an anisotropy parameter of a thin film sample,
A light-emitting optical system that irradiates a measurement area on a thin-film sample placed on a stage with P-polarized light or S-polarized monochromatic light at a predetermined incident angle, and polarization of irradiated light among polarized components included in the reflected light Each measurement point existing in the measurement area while rotating the light receiving optical system that detects the reflected light intensity distribution of the polarized light component orthogonal to the direction on the rotating table that rotates around the normal line set at the center of the measurement area Two-dimensionally detecting each reflected light intensity according to a plurality of incident directions set at predetermined angular intervals,
Among the incident directions in which the reflected light intensity shows a minimum value for each measurement point, the minimum value sandwiched between the two maximum values that are the maximum peak or the minimum value sandwiched between the two maximum values that are the intermediate peak is measured. Determine the azimuth direction of the optical axis at the measurement point based on the incident direction,
In the incident direction in which the minimum value sandwiched between the maximum value where the reflected light intensity is the maximum peak and the maximum value which is adjacent to the maximum value is measured, or in the incident direction where the maximum value which is the maximum peak is measured A method for measuring an optical anisotropy parameter, comprising: determining a polar angle direction of an optical axis at the measurement point based on the measurement result.   2. A main dielectric constant and a film thickness of an anisotropic thin film, which are optical anisotropy parameters, are measured by measuring with an ellipsometer or a reflectometer from at least two arbitrary directions based on the determined azimuth angle direction. The optical anisotropy parameter measuring method as described. An optical anisotropy parameter measuring device that measures the azimuth and polar angle directions of an optical axis that is an anisotropy parameter of a thin film sample,
A light-emitting optical system that irradiates P-polarized light or S-polarized monochromatic light at a predetermined incident angle to a measurement point on a thin film sample placed on a stage;
A light receiving optical system for detecting the reflected light intensity of the polarized light component orthogonal to the polarization direction of the irradiated light in the reflected light according to the incident direction;
A rotary table that rotates the light emitting optical system and the light receiving optical system around a normal line set at a measurement point, and irradiates the measurement point with light from a plurality of incident directions set at predetermined angular intervals;
In the incident direction in which the reflected light intensity exhibits a minimum value, the minimum value sandwiched between the two maximum values that are the maximum peak or the minimum value sandwiched between the two maximum values that are the intermediate peak is measured in the incident direction. And determining the azimuthal direction of the optical axis at the measurement point, and measuring the minimum value sandwiched between the maximum value at which the reflected light intensity becomes the maximum peak and the maximum value at the adjacent intermediate peak. An optical anisotropy parameter comprising: an arithmetic processing unit for determining a polar angle direction of an optical axis at a measurement point based on an incident direction in which a maximum value that is a direction or a maximum peak is measured measuring device.   A tilt adjustment mechanism that adjusts the tilt of the rotation axis with respect to the normal line, a height adjustment mechanism that matches the height of the intersection of the optical axes of the light emitting optical system and the light receiving optical system with the thin film sample, a light emitting optical system, and light receiving 9. The optical anisotropy parameter measuring apparatus according to claim 8, further comprising at least one of an XY moving mechanism for matching an intersection position of optical axes of the optical system with an arbitrary measurement point.   The first angle at which the incident direction of monochromatic light of P-polarized light or S-polarized light that is incident at a predetermined angular interval centered on the normal line is expected to have a minimum value sandwiched between two maximum values that have the maximum peak. And the second angle at which there is a local minimum value between the local maximum value that is the maximum peak and the local maximum value that is the intermediate peak, the local maximum value that is the maximum peak, or the local maximum value that is the intermediate peak. 9. The optical anisotropy parameter measuring apparatus according to claim 8, wherein a plurality of centers are set at predetermined angular intervals and at predetermined angular intervals. An optical anisotropy parameter measuring device that measures the azimuth and polar angle directions of an optical axis that is an anisotropy parameter of a thin film sample,
A light-emitting optical system for irradiating P-polarized light or S-polarized monochromatic light at a predetermined incident angle to a measurement area on a thin film sample placed on a stage;
By measuring the reflected light intensity distribution of the polarized light component included in the reflected light and orthogonal to the polarization direction of the irradiated light, the reflected light intensity at each measurement point in the measurement area is changed to the incident direction. A light-receiving optical system having a two-dimensional light-receiving element to detect according to
A rotating table that rotates the light emitting optical system and the light receiving optical system around a normal line set in the measurement area, and irradiates the measurement area with light from a plurality of incident directions set at predetermined angular intervals;
Among the incident directions in which the reflected light intensity shows a minimum value for each measurement point, the minimum value sandwiched between the two maximum values that are the maximum peak or the minimum value sandwiched between the two maximum values that are the intermediate peak is measured. The azimuth angle direction of the optical axis at the measurement point is determined based on the incident direction, and the minimum value sandwiched between the maximum value at which the reflected light intensity becomes the maximum peak and the maximum value at the adjacent intermediate peak is obtained. An optical processing apparatus comprising an arithmetic processing unit for determining a polar angle direction of the optical axis at the measurement point based on the measured incident direction or the incident direction in which the maximum value that is the maximum peak is measured. Isotropic parameter measuring device. The optical anisotropy parameter measurement apparatus according to claim 8 or 11, wherein the stage is a stage of a rubbing apparatus, an optical alignment processing apparatus or other optical anisotropy imparting apparatus that imparts optical anisotropy to a thin film sample.

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