TW201623935A - A system for measuring anisotropy, a method for measuring anisotropy and a calibration method thereof - Google Patents

Abstract

This invention provides a system embodiment for measuring anisotropy, including a radial polarizer transforming polarization directions of an incident light into radial directions; a (non-polarized beam splitter) NPBS having a transflective surface, in which the incident light partially transmits the transflective surface and becomes a partially incident light; an objective lens receiving the partially incident light and focusing the partially incident light onto a test sample and receiving a reflected light reflected from the test sample, in which the reflected light is reflected back to the transflective; an analyzer receiving the reflected light and generating an output light, in which polarization directions of the output light are transforming into transmission axis of the analyzer; an image sensor receiving the output light and generating an intensity distribution diagram of the test sample; and a operational processor obtaining an reflectance curve of the test sample according to the intensity distribution diagram of the test sample and obtaining anisotropy of the test sample by fitting the reflectance curve of the test sample with a modified Jones calculus model.

Description

Anisotropy measurement system, anisotropy measurement method and correction method thereof

The present invention relates to an anisotropic measuring system, method and method of correcting same.

Due to the popularity of high-resolution mobile devices, the current in-plane switching (IPS) panel will gradually adopt optical alignment technology in the array process to improve panel resolution. At present, the alignment method used is the rubbing alignment. Since the thin-film transistor is a hill-like structure, the alignment of the cotton brush is at a high and low undulation, and the alignment result is poor. The contrast is reduced.

The light alignment is performed by using ultraviolet light (UV), which is incident on the alignment film (PI) according to the set linear polarization. The electric field with a specific oscillation direction interrupts the specific direction bonding of the alignment film, and the remaining alignment The membrane molecules exhibit anisotropy, that is, the alignment film exhibits uniaxial crystal characteristics. After the liquid crystal is poured, the attraction of the liquid crystal molecules and the alignment film causes the liquid crystal molecules to be positioned in a specific direction, wherein the anisotropy is evaluated The key parameters of the orientation alignment (anchoring) of the liquid crystal.

The necessity of performing anisotropy measurement in the optical alignment is the improvement of the material of the panel by the panel manufacturer, the parameter adjustment of the exposure apparatus (light intensity, exposure time, etc.), and the surface treatment of the alignment film. To adjust the size of the anisotropy. When the anisotropy is small, the liquid crystal molecules to which the electric field is applied are not pulled back or scattered after the electric field is zeroed. Furthermore, the inconsistency of the anisotropy is another problem, the liquid crystal panel can operate correctly, and the liquid crystal molecules must be aligned in the same direction. Therefore, the single-optical axis anisotropic alignment film plays an important role. When the alignment film has uniform anisotropy, the display effect is good and no defects are generated. However, if the anisotropy is inconsistent, the liquid crystal molecules are arranged in a stray, or If it cannot be returned after being powered on, the display will be defective. At present, the optical alignment technology is a newly introduced technology, and the panel manufacturer has insufficient grasping of the parameters of the alignment film, and the problem of inconsistent anisotropy is highlighted.

The defects generated by the anisotropy cannot be monitored in the front stage (array segment), and it will not be discovered until the latter part of the process (cell segment) (the cell gap is not evenly measured), even the module segment will be It was found that defects occurred, and many material costs (including glass substrates, liquid crystals, polarizing plates, etc.) were wasted. The anisotropic measurement technology proposed by the invention can simplify the complexity of the mechanism, reduce the size of the probe, integrate it easily into the online measuring device, and improve the reliability.

Embodiments of the present invention disclose an anisotropic measurement system, including: a radial polarizer that converts a polarization direction of incident light generated by a light source into Radial; non-polarizing beam splitter having a penetrating reflecting surface, the incident light partially penetrates the reflecting surface to form part of the incident light; the objective lens receives part of the incident light, focuses part of the incident light to the sample to be tested, and receives the reflection from The sample to be tested has an elliptically polarized reflected light and is incident parallel to the penetrating reflecting surface; the analyzer receives the reflected light reflected from the penetrating reflecting surface and generates output light, and the polarization direction of the output light is converted into an analyzer. The direction of the transmission axis; the image detector receives the output light and generates a reflection light intensity distribution map of the sample to be tested with a shape similar to a circle; and an arithmetic processor, and the sample to be tested is obtained according to the reflected light intensity distribution map of the sample to be tested Reflecting the light intensity distribution curve, and fitting the reflected light intensity distribution curve of the sample to be tested by modifying the Jones operation model to obtain the anisotropy of the sample to be tested.

The embodiment of the invention discloses an anisotropic measuring system, comprising: a linear polarizer, converting a polarization direction of incident light generated by a light source into a direction of a first transmission axis of the linear polarizer; and a non-polarization beam splitter , having a penetrating reflecting surface, the incident light partially penetrates the reflecting surface to form part of the incident light; the objective lens receives part of the incident light, focuses part of the incident light to the sample to be tested, and receives the elliptically polarized reflection from the sample to be tested The reflected light is incident parallel to the penetrating reflecting surface; the linear analyzer receives the reflected light reflected from the penetrating reflecting surface and generates an output light, and the polarization direction of the output light is converted into a first of the linear analyzer a transmissive axis direction; an image detector that receives the output light and generates a reflected light intensity distribution map of the sample to be tested with a shape approximately circular; and an arithmetic processor that obtains a map according to the reflected light intensity of the sample to be tested The reflected light intensity distribution curve of the sample to be tested is obtained, and the reflected light intensity distribution curve of the sample to be tested is fitted by a modified Jones operation model to obtain the anisotropy of the sample to be tested.

An embodiment of the present invention discloses an anisotropic measurement method, including: converting a polarization direction of incident light into a direction of a first transmission axis of a polarizer by a polarizer; and making an incident light portion by a non-polarization beam splitter Passing through the non-polarizing beam splitter to form part of the incident light; focusing part of the incident light to the sample to be tested by the objective lens and receiving the reflected light having elliptically polarized reflection from the sample to be tested, and then outputting to the non-polarizing beam splitter in parallel; The polarizer receives the reflected light reflected from the non-polarization beam splitter and generates output light, wherein the polarization direction of the output light is converted into the direction of the second transmission axis of the analyzer; the shape of the output light is approximately a circle to be tested The reflected light intensity distribution map of the sample is used to obtain a reflected light intensity distribution curve of the sample to be tested; and the reflected light intensity distribution curve of the sample to be tested is obtained by modifying the Jones operation model to obtain the anisotropy of the sample to be tested.

The invention discloses a method for correcting an anisotropic measurement method according to the foregoing embodiment, which comprises: obtaining a reflected light intensity distribution map of a standard sample whose shape is approximately a circle; and obtaining a light intensity distribution map according to a standard sample The reflected light intensity distribution curve of the standard sample is obtained; and the reflected light intensity distribution curve of the standard sample is fitted by a Jones calculation model to obtain a correction matrix.

The invention discloses an anisotropic measurement method, comprising: converting a polarization direction of incident light into a first penetration of a polarizer by a linear polarizer In the direction of the axis, the linear polarizer rotates 360 degrees around the first optical axis; the incident light partially penetrates the non-polarizing beam splitter to form part of the incident light by the non-polarizing beam splitter; and the incident light is focused by the objective lens to be tested And receiving the reflected light having elliptically polarized reflection from the sample to be tested and outputting to the non-polarization beam splitter in parallel; receiving the reflected light reflected from the non-polarization beam splitter by the linear analyzer and generating output light, wherein the output light The polarization direction is converted into the direction of the second transmission axis of the analyzer, the linear analyzer rotates 360 degrees around the second optical axis and rotates 360 degrees synchronously with the linear analyzer; the shape of the output light is approximately circular The reflected light intensity distribution map of the sample is obtained to obtain a reflected light intensity distribution curve of the sample to be tested; and the relative size of the anisotropy is determined according to the amplitude of the reflected light intensity distribution curve of the sample to be tested.

An embodiment of the present invention discloses an anisotropic measurement system, including: a linear polarizer that converts a polarization direction of incident light generated by a light source into a direction of a first transmission axis of a linear polarizer, wherein the linear polarizer is wound The first optical axis rotates 360 degrees; the non-polarizing beam splitter has a penetrating reflecting surface, and the incident light partially penetrates the reflecting surface to form part of the incident light; the objective lens receives part of the incident light, and focuses part of the incident light to the sample to be tested And receiving the reflected light having the elliptical polarization reflected from the sample to be tested and then parallelly incident to the penetrating reflecting surface; the linear analyzer receives the reflected light reflected from the penetrating reflecting surface and generates output light, and the polarization direction of the output light is Converting into a second penetration axis direction of the linear analyzer, wherein the linear analyzer rotates 360 degrees around the second optical axis and rotates 360 degrees synchronously with the linear analyzer; the image detector receives the output light and generates The shape is approximated as a circle of the reflected light intensity distribution of the sample to be tested; and the arithmetic processor extracts the reflected light intensity distribution curve of the sample to be tested on the position of the reflected light intensity distribution of the sample to be tested, and according to different The magnitude of the amplitude of the reflected light intensity distribution curve of the sample to be tested is used to determine the relative size of the anisotropy.

100, 200, 300, 400‧‧‧ anisotropy measurement system

10‧‧‧Light source

11‧‧‧ Collimating lens

12a, 12b‧‧‧ Radial polarizer

12c, 12d‧‧‧ linear polarizer

14‧‧‧No polarization beam splitter

16‧‧‧ Objective lens

17‧‧‧Test samples

21‧‧‧Substrate

18a‧‧‧ Tangential analyzer

D‧‧‧thickness

18b, 18c, 18d‧‧‧ linear analyzer

20‧‧‧Image Detector

22‧‧‧Operation processor

Lo‧‧‧ incident light

Lin‧‧‧ Partial incident light

Lreflec‧‧·reflected light

Lout‧‧‧ output light

No‧‧‧normal refractive index

Ne‧‧‧Abnormal refractive index

Θ‧‧‧ The angle between the incident light and the optical axis

Θi‧‧‧ incident angle

Ψ‧‧ Azimuth

O‧‧‧ Center

P1~Pn‧‧‧

C1‧‧‧ inner circle

C2‧‧‧ outer circle

θtilt‧‧‧Tilt angle

C _{std_fit ‧‧‧Standard} sample fitting circle

C _{sample_fit} ‧‧‧Filling sample to fit

a, b, c, d, e‧‧ path

The invention will be described below in conjunction with the drawings.

Figure 1 is a schematic illustration of an anisotropic measurement system of a first embodiment of the present invention.

2a-2c are schematic diagrams illustrating the principles of the anisotropic measurement systems and methods of all embodiments of the present disclosure.

Figure 3a illustrates the principles of the path of partially incident and reflected light and the principles of the anisotropic measuring apparatus and method of the present invention using paths a, b, c, d, e.

Figure 3b shows the positional correspondence of the partially incident light, the reflected light, and the output light on a circle (sample fitting circle) representing the above light, respectively.

4a-4c are diagrams showing polarization states and intensities of partially incident light, reflected light, and output light in the anisotropic measuring systems of the first to third embodiments of the present invention.

Figure 4d is a diagram showing polarization patterns and intensities of partially incident light, reflected light, and output light in a linear polarizer and linear synchronous pivoting in the anisotropic measuring system of the fourth embodiment of the present invention. .

Figure 4e is a diagram showing the same sample to be tested in the fourth embodiment of the present invention. The reflected light intensity distribution curve of the sample to be tested is received by P incidence S (left circle) and S incident S (right circle).

Figure 5 is a schematic illustration of an anisotropic measurement system of a second embodiment of the present invention.

Figure 6 is a schematic illustration of an anisotropic measurement system of a third embodiment of the present invention.

Figure 7 is a schematic illustration of an anisotropic measurement system of a fourth embodiment of the present invention.

Figure 8a is a flow chart illustrating an anisotropic measurement method of a fifth embodiment and a sixth embodiment (including a calibration procedure) according to the present invention.

Fig. 8b is a flow chart for explaining the reflected light intensity distribution curve of the standard sample and the curve of the reflected light intensity of the sample to be tested according to the fifth embodiment of the present invention.

Figure 9a is a standard sample intensity profile obtained by an embodiment of the anisotropic measurement system and method of the present invention.

Figure 9b is a graph showing the intensity distribution of the sample to be tested obtained by the embodiment of the anisotropic measurement system and method of the present invention. The figure below shows the intensity distribution curve of the sample to be tested.

1 is a schematic diagram of an anisotropic measurement system 100 in accordance with a first embodiment of the present invention. The anisotropy measuring device 100 includes a light source 10 and a radial bias A radiator polarizer 12a, a non-polarization beam splitter 14, an objective lens 16, a tangential analyzer 18, an image detector 20, and an arithmetic processor 22. The light source 10 generates incident light Lo, wherein the incident light Lo is a single wavelength and a non-polarized light. In this embodiment, the light source 10 is a light emitting diode (LED) in combination with a bandpass filter such that the wavelength of the incident light Lo is 633 nm, or a laser having a wavelength of 633 nm is used, but not limited thereto. . In all embodiments disclosed, the wavelength of the incident light may depend on the configuration of the anisotropic measuring device.

In the first embodiment, the anisotropic measuring device 100 further includes a collimating lens 11 that limits the beam diameter of the incident light Lo to a desired value, for example, about 4 millimeters (mm), but not Limited.

The radial polarizer 12 converts the polarization direction of the incident light Lo into a radial direction. The incident light Lo having a radial polarization has a polarization direction at each point of the beam toward the center of the beam.

A non-Polarized Beam Splitter (NPBS) 14 has a transflective surface. The NPBS 14 is caused to partially penetrate the reflecting surface to form part of the incident light Lin according to the ratio of the light intensity, for example, 50:50. The polarization direction of the portion of the incident light Lin is not changed by the NPBS 14, so that the polarization direction of the portion of the incident light Lin is still radial.

The objective lens 16 receives a portion of the incident light Lin, focuses a portion of the incident light Lin to the sample 17 to be tested, and receives an ellipse reflected from the sample 17 to be tested. The polarized reflected light Lreflec is then incident parallel to the penetrating reflecting surface.

The tangential analyzer 18a receives the reflected light Lreflec reflected from the penetrating reflecting surface and generates the output light Lout, and the polarization direction of the output light Lout is converted into a tangential direction. The output light Lout having tangential polarization has a polarization direction at each point of the beam in a tangential direction.

The image detector 20 receives the output light Lout and generates a reflected light intensity distribution map of the sample to be tested whose shape is approximately a circle (refer to FIG. 9b). In all embodiments of the present disclosure, the image detector 20 can be a charge coupled device (CCD) array or a complementary metal oxide semiconductor device (CMOS) array having a two-dimensional image capture function.

The arithmetic processor 22 obtains a reflected light intensity distribution curve of the sample to be tested according to the reflected light intensity distribution map of the sample to be tested, and fits the reflected light intensity distribution of the sample to be tested by a modified Jones calculus model The curve is used to determine the anisotropy of the sample to be tested. In all of the embodiments disclosed herein, the arithmetic processor 22 can be an electronic computer or a device having an electronic computer function.

2a-2c are schematic diagrams illustrating the principles of all embodiments of the anisotropy measurement system and method disclosed herein.

In all the embodiments disclosed in the present invention, the sample to be tested 17 may be a uniaxial anisotropic material such as an alignment film or the like, and the substrate 21 may be an isotropic material such as glass or the like. The Refractive Index Ellipsoid is used to illustrate the principles of the anisotropic measurement system and method of the present invention. Suppose the alignment film is a negative uniaxial, i.e., ordinary refractive index (ordinary index) no less than the extraordinary refractive index (extraordinary index) ne, where ne is the extraordinary refractive index axis indicates the optical axis, and the other index ellipsoid is assumed that the azimuth angle [Psi] ( The azimuthal angle is 0 degrees (the optical axis is in the XZ plane) and is inclined at an inclination angle θtilt as shown in the schematic diagram of FIG. The incident light may penetrate the sample 17 to be tested to the substrate 21 and cause reflection at the substrate 21. However, if the substrate 21 is isotropic, the reflection on the substrate 21 is not anisotropic reflection, so the reflection of the substrate 21 can be ignored and the anisotropy of the sample 17 to be tested can be obtained.

Referring to the schematic diagram of Fig. 2a, when the incident partial polarization light Lin is a P wave and the parallel optical axis is incident on the single optical axis material, the P wave senses a refractive index of no, so birefringence does not occur, and the incident angle of the partially polarized light Lin Is θi. Under this condition, the reflected light Lreflec has only P waves. In addition to the reflection of the interface between the sample 17 to be tested and the substrate 21, the reflected wave at the interface between the sample 17 to be tested and the air is also a P wave.

Referring to Fig. 2b, when the incident partial polarized light Lin is a P wave and the vertical optical axis is incident on the single optical axis material, the P wave senses a refractive index of ne, so that birefringence does not occur. Under this condition, the reflected light Lreflec has only P waves.

Referring to the schematic diagram of Fig. 2c, when the incident partially polarized light Lin has a P wave and an S wave, and the single optical axis material is incident at an angle θ with the optical axis, the partial polarized light Lin senses two refractive indices no and ne, which occurs. Birefringence. At this time, the partially polarized light Lin is divided into a vertical principal plane (XZ plane) of the vibration direction and obeys the ordinary light (o-ray, o-light) of Snell's law, and the vibration direction is parallel to the principal plane and is also observed. Anomalous light (e-ray, e-light) from the law of Sinar. o The light and the e-light are reflected by the sample to be tested 17 and then returned to the air with the S wave and the P wave. Under this condition, the reflected light Lreflec has a component of the S wave and a component of the P wave. When the phase difference ΔΦ of the component of the S wave and the component of the P wave satisfies ΔΦ ≠ kπ , k is an integer, the component of the S wave and the component of the P wave interfere to form a reflected light Lreflec having an elliptically polarized light, wherein , λ is the wavelength, d is the thickness of the sample 17 to be tested, and the refractive index difference Δ n = ne - no .

Referring to the schematic diagram of Fig. 3a-3b, part of the incident light Lin is focused by the objective lens 16 to form a cone beam and is incident on the sample to be tested 17. The paths a, b, c, c, d, e of the cone beam are used to illustrate the partial incident light Lin, the reflected light Lreflec and the output light Lout on the sampling circle of the image detector 20 (hereinafter referred to as the sample fitting circle) Position correspondence. For example, a portion of the incident light Lin along the path a is incident on the sample 17 to be tested at an incident angle θi and a parallel optical axis, and is reflected back to the objective lens 16 by a path e of a vertical optical axis, and is reflected by the non-polarizing beam splitter 17 to form an image. A beam of 90 degrees on the circle is fitted to the sample of the reflected light Lreflec and the output light Lout. The path c is incident on the sample 17 to be tested at an incident angle θi and at an angle θ with the optical axis, and is symmetrically reflected back to the objective lens 16 by a symmetrical normal line (Z-axis), and is reflected by the non-polarization beam splitter 17 to form an image for reflected light. The sample of Lreflec and the output light Lout fits a beam of 180 degrees on the circle. The path e is incident on the sample 17 to be tested at an incident angle θi and perpendicular to the optical axis, and is reflected back to the objective lens 16 by a path e of a parallel optical axis, and is reflected by the non-polarizing beam splitter 17 to form an image of the reflected light Lreflec and the output light Lout. The sample fits a beam of 270 degrees on a circle. Yu This type of push will not be repeated.

4a-4d is a schematic diagram illustrating the polarization state and intensity change of the output light Lout before the reflected light Lreflec enters each of the analyzers before the input light Lin enters the objective lens 16. The first to fourth embodiments of the present invention are described below in conjunction with Figs. 4a-4d, respectively.

In the first embodiment of the present invention, the polarizer is a radial polarizer 12a, and the analyzer is a tangential analyzer 18a. Referring to the schematic diagram of Fig. 4a, the left circle represents the beam before the partial input light Lin enters the objective lens 16. The polarization direction of each of the light beams passing through the radial polarizer 12a is converted into a radial direction, so the polarization direction of each position on the left circle is in the radial direction (toward the center of the circle), wherein the double arrow on the left circle The equal lengths indicate that the intensities are equal, and the symbol ae of the left circle indicates that the light at each position on the left circle enters the corresponding path ae of the sample 17 to be tested, as described in the schematic diagram of Fig. 3a.

The middle circle of Fig. 4a indicates the light beam before the reflected light Lreflec enters the tangential analyzer 18a. As shown in the schematic diagram of FIG. 2a, part of the incident light Lin entering the sample to be tested 17 along the path a is a P wave, so that the reflected light Lreflec reflected off the sample 17 along the path e has only a P wave; the entry along the path e Part of the incident light Lin of the sample to be tested 17 is a P wave, so that the reflected light Lreflec reflected off the sample 17 along the path a has only a P wave. Part of the incident light Lin along the path c has a P wave and an S wave and enters the sample 17 to be tested at an angle θ with the optical axis, so the reflected light Lreflec forms an elliptical polarization. The symbol a-e of the middle circle indicates that the light at each position on the middle circle comes from the corresponding path a-e. Part of the incident light Lin along the path a is in the absence The polarization direction before the polarization beam splitter 14 reflects is the X direction, and after being reflected by the non-polarization beam splitter 14 (the reflected light Lreflec), the polarization direction is the Z direction, so the polarization direction of the light at the 0 degree and 180 degree positions on the left circle. In the X direction, the polarization directions of the rays at 90 degrees and 270 degrees on the middle circle (from paths a and e, respectively) are the Z direction. The polarization of the reflected light Lreflec from the path c is converted into an elliptical polarization, so the polarization direction of the light at a position of 180 degrees on the middle circle is marked as elliptically polarized.

The right circle of Fig. 4a indicates the light beam of the output light Lout. Since the tangential analyzer 18a passes only the tangential polarization component, the reflected light Lreflec that exhibits linear polarization along the paths a, e is cut away from passing through the tangential analyzer 18a, along the path b, The tangential polarization component (short axis direction) of c, d and the reflected light Lreflec exhibiting elliptically polarized light may pass through the tangential analyzer 18a. Among them, the paths a and e have no light to pass, so they are minimum values; the tangential polarization component of the path c is the largest, so it is the maximum value; the paths b and d are the values of the minimum value and the maximum value. The intensity of the output light Lout is incremented by the minimum value of path a (90 degrees) via path b to the maximum value of path c (180 degrees), and then decremented by path d to the minimum value of path e (270 degrees). Then, from the axisymmetric characteristic, it can be inferred that the intensity of the output light Lout is increased from the minimum value of the path e (270 degrees) to the maximum value of 360 degrees, and then decremented to the minimum value of the path a. The intensity on the right circle of the light beam representing the output light Lout thus has a periodic intensity distribution, and the periodic intensity distribution of this output light Lout carries information with the anisotropy of the sample 17 to be tested.

Due to the polarization pattern and intensity of each position in the beam of the present invention The degree distribution has an axisymmetric property, and the paths a and c are the minimum and maximum values of the periodic intensity distribution, respectively, and the paths b and d are values between the minimum value and the maximum value, so the ellipse of the paths b and d are equal. And less than the ellipse of path c. Further, in the above description, the long axis of the elliptical polarization is in the radial direction, but there is another possibility that the long axis of the elliptical polarization is perpendicular to the radial direction, and the end depends on the values of no and ne, and the above description only discloses the elliptical polarization. The long axis is radial, but is not intended to limit the invention.

Figure 5 is a schematic illustration of an anisotropic measurement system 200 in accordance with a second embodiment of the present invention, wherein the polarizer is a radial polarizer 12b and the analyzer is a linear analyzer 18b. Referring to the schematic diagram of FIG. 4b, since the polarizer of FIG. 4b and the polarizer of FIG. 4a are both radial polarizers, part of the input light Lin of the second embodiment (left circle of FIG. 4b) and reflected light The polarization pattern and intensity change of Lreflec (the circle in Fig. 4b) are the same as the left circle of Fig. 4a and the right circle of Fig. 4a. Different from the first embodiment, the second embodiment uses the linear analyzer 18b. The transmission axis of the linear analyzer 18b is set in the Y direction, and therefore, the linear analyzer 18b passes only the polarization component in the Y direction of the reflected light Leflec, so it exhibits linear polarization along the paths a, e (Z The reflected light Lreflec of the direction is cut away from passing through the linear analyzer 18b, and the Y-direction polarization component of the reflected light Lreflec along the paths b, c, d and exhibiting elliptically polarized light can pass through the linear analyzer 18b. Among them, the paths a and e have no light to pass, so they are minimum values; the path c has the largest polarization component in the Y direction, so it is the maximum value; the paths b and d are the values between the minimum value and the maximum value.

Figure 6 is a schematic illustration of an anisotropic measurement system 300 in accordance with a third embodiment of the present invention, wherein the polarizer is a linear polarizer 12c and the analyzer is a linear analyzer 18c. Referring to Fig. 4c, the transmission axis of the linear polarizer 12c of the third embodiment is disposed in the X direction, and therefore, the polarization directions of the partial input lights Lin are all in the X direction.

In the same manner as the first and second embodiments, part of the incident light Lin is incident on the sample 17 to be tested along the paths a, e and forms reflected light Lreflec having linear polarization (Z direction) at 90 degrees and 270 degrees. Unlike the first and second embodiments, a portion of the incident light Lin incident on the sample 17 to be tested along the path c has only S waves. Nonetheless, a portion of the incident light Lin incident on the sample to be tested 17 along the path c is not incident on the sample 17 to be tested on the parallel optical axis, so the 180-degree reflected light Lreflec may still be elliptically polarized. The polarization patterns and intensities of the reflected light Lreflec (paths b, d) at other angles are the same as in the first and second embodiments. The elliptical polarization of the third embodiment has a long axis direction in the Y direction.

The transmission axis of the linear analyzer 18c of the third embodiment is disposed in the Y direction, so the linear analyzer 18c passes only the polarization component in the Y direction of the reflected light Leflec, so it exhibits linear polarization along the paths a, e (Z The reflected light Lreflec of the direction is cut away from passing through the linear analyzer 18b, and the Y-direction polarization component of the reflected light Lreflec along the paths b, c, d and exhibiting elliptically polarized light can pass through the linear analyzer 18b. Among them, the paths a and e have no light to pass, so they are minimum values; the path c has the largest polarization component in the Y direction, so it is the maximum value; the paths b and d are the values between the minimum value and the maximum value.

Figure 7 is a schematic illustration of an anisotropic measurement system 400 in accordance with a fourth embodiment of the present invention, wherein the polarizer is a linear polarizer 12d and the analyzer is a linear analyzer 18d. The transmission axis of the linear polarizer 12d is initially set in the X direction and is rotated 360 degrees around the optical axis (Z axis) by a motor (not shown), and the transmission axis of the linear analyzer 18d is initially set in the Y direction. And the motor (not shown) rotates 360 degrees around the optical axis (X axis) in synchronization with the transmission axis of the linear analyzer 12d. Here, the optical axis indicates the direction in which the light travels, and its meaning is different from the optical axis of the aforesaid anisotropic material, and those skilled in the art can know the difference between the two. Synchronous pivoting is simultaneous counterclockwise or simultaneous clockwise rotation and rotates at an equal angular velocity. Fig. 4d is a view showing a polarization state and intensity change of a part of the input light Lin, the reflected light Lreflec, and the output light Lout when the linear polarizer 12d and the linear analyzer 18d are rotated at different angles in the fourth embodiment of the present invention. When rotated by 0 degrees, the polarization patterns and intensity changes of the partial input light Lin, the reflected light Lreflec, and the output light Lout are the same as in the third embodiment. When rotated 90 degrees or 180 degrees, it can be observed that the polarization patterns of each position are rotated by 90 degrees or 180 degrees, respectively. The remaining rotation angles (270 degrees, 360 degrees) can be analogized and will not be described again. We can observe that the intensity of the output light Lout also exhibits a periodic distribution, but the polarization directions are different at different rotation angles.

A variation of the fourth embodiment can compare the relative magnitude of the heterogeneity of different samples to be tested. The components and operation modes of this modification are as described above and will not be described again. Selecting the light intensity at a certain position on the image formed by the image detector 20 (ie, the intensity distribution map of the sample to be tested) may represent that part of the incident light Lin is incident on the P wave. The sample 17 is sampled and the output light Lou is received by the image detector by the S wave (P incident S is received), or part of the incident light Lin is incident on the sample 17 to be tested with the S wave, and the output light Lou is received by the image detector 20 with the P wave. (S incident P reception). Taking the rotation angle of the linear polarizer 12d and the linear analyzer 18d as 0 degrees as an example, the path e represents the case where the P incident S is received. After both rotations of 360 degrees, the reflected light intensity distribution map of the sample to be tested of different samples to be tested at this position will obtain the reflected light intensity distribution curve of the sample to be tested which exhibits periodic intensity changes. In this case, it is not necessary to fit the reflected light intensity distribution curve of the sample to be measured by the Jones matrix to obtain the absolute value of the anisotropy, but to take the sample to be tested at a position on the reflected light intensity distribution map of the sample to be tested. The reflected light intensity distribution curve of the sample to be tested, and the relative size of the anisotropy is determined according to the amplitude of the reflected light intensity distribution curve of the sample to be tested.

The left circle of Fig. 4e shows the reflected light intensity distribution curve of the sample to be tested along the path e (P incident S is received), which exhibits a periodic intensity change at a period of 90 degrees. When different samples to be tested need to compare the relative size of the anisotropy, the relative magnitude of the anisotropy can be judged by the amplitude of the reflected light intensity distribution curve of the sample to be tested. For example, the larger the amplitude, the greater the anisotropy. In the configuration of P incident S reception, the azimuth of the index ellipsoid occurs between the minimum of two large maxima (45 degrees, 315 degrees) or between two smaller maxima (135 degrees, The minimum value of 225 degrees), that is, the azimuth is 0 degrees or 180 degrees (the two representations are equivalent). When the azimuth angle of the sample to be tested 17 is 0 degrees (or 180 degrees), the light is received by the P incident S, and the angle of rotation is 0 degrees, 90 degrees, 180 degrees, 360 degrees, the reflected light intensity distribution of the sample to be tested The curve is a minimum value; when the angle of rotation is 45 degrees, 135 degrees, 225 degrees, and 315 degrees, it is a maximum value, and the maximum values of 45 degrees and 315 degrees are slightly larger than the maximum values of 135 degrees and 225 degrees. The maximum value of the reflectance differs from the minimum value by about 2 × 10 ^-5 .

The right circle of Fig. 4e shows the reflected light intensity distribution curve of the sample to be tested received by S incident S, which exhibits a periodic intensity change at a period of 180 degrees. When different samples to be tested need to compare the relative size of the anisotropy, the relative magnitude of the anisotropy can be judged by the amplitude of the reflected light intensity distribution curve of the sample to be tested. For example, the larger the amplitude, the greater the anisotropy. In the configuration of S-incident S-receiving, the azimuth of the index ellipsoid occurs at a minimum between two maxima (90 degrees, 270 degrees) or a minimum between two polar values (0 degrees, 360 degrees). , that is, the azimuth is 180 degrees or 0 degrees (the two forms are equivalent). When the azimuth angle of the sample to be tested 17 is 180 degrees (or 0 degrees), the light is received by the S incident S, and the angle of rotation is 0 degrees, 180 degrees, 360 degrees, the reflectance is a minimum value; the angle of rotation is At 90 degrees and 270 degrees, it is a maximum value, and the maximum values are equal. The maximum value of the reflectance differs from the minimum value by about 2.25 × 10 ^-3 .

Hereinafter, the anisotropy measurement method according to the fifth embodiment of the present invention will be described with reference to the second embodiment as a case of Jones calculus. The anisotropy measurement method according to the fifth embodiment of the present invention is applicable to the anisotropy measurement systems disclosed in the foregoing first to fourth embodiments. Referring to Fig. 8a, when the unpolarized incident light Lo penetrates the radial polarizer 12b, the polarization direction of the incident light Lo changes to a radial polarization. Assuming that the electric field intensity of the incident light Lo is Eo, and the electric field intensity after penetrating the radial polarizer 12b is Ei, then Where ψ is the azimuthal angle representing the refractive index ellipsoid of the sample to be tested. In all embodiments of the present disclosure, ψ =0. The range of ψ can range from 0 to π ( ψ =0~ π ).

The objective lens 16 receives a portion of the incident light Lin, focuses a portion of the incident light Lin to the sample 17 to be tested, and receives the reflected light Lreflec having an elliptically polarized reflection from the sample 17 to be tested, and then is incident parallel to the penetrating reflecting surface. In the second embodiment, the sample to be tested 17 is an alignment film, and the Jones matrix of the sample to be tested 17 is The four entries of the matrix R _s include three parameters: the abnormal refractive index n _{e of} the sample to be tested 17 , the normal refractive index n _{o ,} and the thickness d. In other words, n _e , n _o and d of the sample to be tested 17 can be obtained by finding the Jones matrix R _s . In all of the embodiments disclosed herein, the numerical aperture (NA) of the objective lens 16 may be 0.9, corresponding to a dimming angle (twice the angle of incidence θi) of about 64 degrees. In the actual measurement, the sample 17 to be tested has ne = 1.6391, no = 1.6150, and d = 0.238 μm, so the anisotropy = d (ne-no) = 5.7358 nm.

The linear analyzer 18b receives the reflected light Lreflec reflected from the penetrating reflecting surface and generates output light Lout. In the second embodiment, the transmission axis of the linear analyzer 18b is in the Y direction, so the Jones matrix of the linear analyzer 18b is . The elliptically polarized reflected light Lreflec whose polarization direction is the same as the direction of the transmission axis of the linear analyzer 18b will be extracted, and the component whose polarization direction is different from the penetration direction cannot pass through the linear analyzer 18b. As described in Figure 4b.

In step S4, the image detector 20 receives the output light Lout and generates a reflected light intensity distribution map of the sample to be tested whose shape is approximately circular (Fig. 9b). In step S5, the arithmetic processor 22 obtains a reflected light intensity distribution curve of the sample to be tested according to the reflected light intensity distribution map of the sample to be tested (Fig. 9b, lower drawing). In step S6, the arithmetic processor 22 fits the reflected light intensity distribution curve of the sample to be tested by a modified Jones calculus model to determine the anisotropy of the sample to be tested.

Hereinafter, the anisotropic measurement method including the correction method according to the sixth embodiment of the present invention will be described with reference to the second embodiment as an example. The anisotropy measurement method including the correction method of the sixth embodiment of the present invention is applicable to the anisotropy measurement systems disclosed in the foregoing first to fourth embodiments. Referring to FIG. 8a, in the sixth embodiment, when the anisotropic measuring device 200 is used for the first time, since the non-polarizing beam splitter 14 and the objective lens 16 change the phase and amplitude of the incident light L0 and the reflected light Lreflec, the measurement accuracy is accurate. Sexuality causes errors, so it is necessary to introduce a correction matrix Tc in the Jones operation to correct the error caused by the NPBS 16 and the objective lens 16. The calibration process is first performed to obtain the correction matrix Tc. In step S0, it is judged whether or not the correction matrix Tc needs to be acquired. When the anisotropy measurement device is used for the first time, the determination is YES, otherwise the determination is NO, and the flow proceeds to step S1.

In step S1, a standard sample reflected light intensity distribution map whose shape of the standard sample is approximately circular is obtained, as shown in Fig. 9a. In the second embodiment The standard sample is an aluminized mirror, and the flow proceeds to step S2.

In step S2, a standard sample reflected light intensity distribution curve (not shown) is obtained from the standard sample reflected light intensity distribution map, and the flow proceeds to step S3.

In step S3, the standard sample reflected light intensity distribution curve is fitted with a Jones operation model to obtain a correction matrix Tc, wherein the Jones operation model is as follows:

Wherein, E _out represents the intensity of the output light Lout received by the image detector 20, and the correction matrix , ε _c and δ _c represent the absorption coefficient of the non-polarizing beam splitter 14 and the objective lens 16 and the phase difference introduced; ; Jones matrix of aluminized mirrors ; coordinate conversion matrix of incident light and reflected light ; , Jones matrix of analyzer 18 . Multiplying Tc twice in the Jones operation model indicates that the light penetrates the reflection non-polarization beam splitter 14 and the objective lens 16 twice.

In step S2, the standard sample reflected light intensity distribution curve is obtained according to the standard sample reflected light intensity distribution map, and further includes steps S1_1 to S1_5, as shown in FIG. 8b.

In step S1_1, on the standard sample reflected light intensity distribution map The center point O is selected (Fig. 9a), and the flow proceeds to step S1_2.

In step S1_2, the inner circle C1 is formed by drawing a circle with the center point O as a center and the first length as a radius, and the outer circle C2 is formed by drawing a circle with the center point O as a center and the second length as a radius. The area between the inner circle C1 and the outer circle C2 is a region of interest (ROI). The flow proceeds to step S1_3.

In step S1_3, the complex lines OP1 to OPn of the points P1 to Pn on the center point O and the outer circle C2 are made, and the flow proceeds to step S1_4.

In step S1_4, when the light intensity indicated on the line OP1~OPn is lower than the critical value from the inside to the outside (for example, 50% of the maximum intensity), the position where the critical value is defined is a complex boundary point (Fig. 9a, cross) Symbol marker). The flow proceeds to step S1_5.

In step S1_5, the boundary points are fitted to obtain a standard sample fitting circle C _{std_fit} . The standard sample reflected light intensity distribution curve is obtained by taking the value of the intensity of the standard sample fitting circle C _{std_fit} along 360 degrees on the circle.

After the correction matrix Tc is known, the measurement procedure of the sample to be tested can be performed, and the flow proceeds to step S4. In step S4, a standard sample reflected light intensity distribution map whose shape of the standard sample is approximately circular is obtained, as shown in Fig. 9b. In the second embodiment, the sample to be tested 17 is an alignment film, and the flow proceeds to step S5.

In step S5, the reflected light intensity distribution curve of the sample to be tested is obtained according to the reflected light intensity distribution map of the sample to be tested (Fig. 9b is lower), and the flow proceeds to step S6.

In step S6, the reflected light intensity distribution curve of the standard sample is fitted with a modified Jones calculus model to determine the anisotropy of the sample to be tested, wherein the modified Jones operation model is as follows:

among them The intensity (already corrected) of the output light Lout received by the image detector 20 is indicated, and the correction matrix Tc in (Formula 2) uses the correction matrix Tc, Rs obtained through the steps S1 to S3 as the Jones matrix of the alignment film. R _φ , R _M , And T _a is the same as that shown in (Formula 1).

In step S5, determining the reflected light intensity distribution curve of the sample to be tested according to the reflected light intensity distribution map of the sample to be tested further includes steps S2_1 to S2_5, as shown in FIG. 8b.

Steps S2_1 to S2_5 are similar to steps S1_1 to S1_5, and in order to simplify the description, only step S2_5 is selected for explanation. In step S2_5, the boundary points are fitted to obtain a sample fitting circle C _{sample_fit to} be tested. In the sample to be tested, the fitting circle C _{sample_fit} takes the intensity of 360 degrees along the circle to obtain the intensity distribution curve of the sample to be tested (Fig. 9 below).

The present invention has been described above with reference to the embodiments and the accompanying drawings. The embodiments disclosed herein are merely illustrative of the embodiments of the anisotropic measuring system, the anisotropic measuring method and the correcting method thereof. However, it is not intended to limit the scope and spirit of the invention. The above assumptions do not lose their generality and do not create self-inconsistency. It is to be understood by those skilled in the art that the scope of the present invention is not limited by the scope and spirit of the invention and the scope of the invention. Can make some changes, additions, deletions and replacements.

100‧‧‧ anisotropy measurement system

10‧‧‧Light source

11‧‧‧ Collimating lens

12a‧‧‧ Radial polarizer

14‧‧‧No polarization beam splitter

16‧‧‧ Objective lens

17‧‧‧Test samples

18a‧‧‧ Tangential analyzer

20‧‧‧Image Detector

21‧‧‧Substrate

22‧‧‧Operation processor

Lo‧‧‧ incident light

Lin‧‧‧ Partial incident light

Lreflec‧‧·reflected light

Lout‧‧‧ output light

Claims (20)

An anisotropic measuring system comprising: a radial polarizer that converts a polarization direction of one incident light into a radial direction; and a non-polarizing beam splitter having a penetrating reflecting surface, the incident light portion Passing through the penetrating reflecting surface to form a part of incident light; an objective lens receiving the part of the incident light, focusing the part of the incident light to a sample to be tested, and receiving the reflected light having one of the elliptical polarizations reflected from the sample to be tested Parallel incidence to the penetrating reflecting surface; an analyzer that receives the reflected light reflected from the penetrating reflecting surface and generates an output light, and the polarization direction of the output light is converted into one of the analyzers The direction of the axis; an image detector receiving the output light and generating a map of the intensity of the reflected light of the sample to be measured in a shape approximated to a circle; and an arithmetic processor, which is obtained according to the reflected light intensity distribution map of the sample to be tested A reflected light intensity distribution curve of the sample to be tested is obtained by fitting a reflected light intensity distribution curve of the sample to be tested by a modified Jones operation model to obtain an anisotropy of the sample to be tested. The anisotropic measuring system according to claim 1, wherein the analyzer is an all-direction analyzer, and the direction of the transmission axis is tangential. The anisotropic measuring system according to claim 1, wherein the analyzer is a linear analyzer, and the direction of the transmission axis is the Y direction. An anisotropic measurement system comprising: a linear polarizer that converts a polarization direction of one of the incident light into a direction of a first transmission axis of the linear polarizer; a non-polarization beam splitter having a penetrating reflection surface, the incident light Partially penetrating the penetrating reflecting surface to form a portion of incident light; an objective lens receiving the portion of the incident light, focusing the portion of the incident light to a sample to be tested, and receiving a reflection of one of the elliptical polarizations reflected from the sample to be tested The light is incident parallel to the penetrating reflecting surface; a linear analyzer receives the reflected light reflected from the penetrating reflecting surface and generates an output light, and the polarization direction of the output light is converted into the linear analyzer a second through-axis direction; an image detector receiving the output light and generating a map of the reflected light intensity of the sample to be measured in a shape approximately circular; and an arithmetic processor for distributing the intensity of the reflected light according to the sample to be tested The figure obtains a reflected light intensity distribution curve of one sample to be tested, and fits the reflected light intensity distribution curve of the sample to be tested by a modified Jones operation model to obtain the anisotropy of the sample to be tested. The anisotropic measuring system of claim 4, wherein the direction of the first transmission axis is the X direction, and the direction of the second transmission axis is the Y direction. The anisotropic measuring system of claim 4, wherein the linear polarizer rotates 360 degrees around a first optical axis, and the linear analyzer rotates 360 degrees around a second optical axis and The linear analyzer rotates 360 degrees synchronously, the first optical axis Z direction and the second optical axis are X directions, and the first The starting direction of a penetrating axis is the X direction, and the starting direction of the second penetrating axis is the Y direction. The anisotropic measurement system of claim 1 or 4, wherein the modified Jones operation model includes a correction matrix to correct the error caused by the non-polarization beam splitter and the objective lens. An anisotropic measuring method comprising: converting a polarization direction of an incident light into a direction of a first transmission axis of the polarizer by a polarizer; and the incident light portion by a non-polarization beam splitter Passing through the non-polarization beam splitter to form a portion of the incident light; focusing the portion of the incident light onto a sample to be tested by an objective lens and receiving the reflected light having one of the elliptically polarized reflections from the sample to be tested, and outputting the parallel light to the a polarization beam splitter; receiving, by an analyzer, the reflected light reflected from the non-polarization beam splitter and generating an output light, wherein a polarization direction of the output light is converted into a second transmission axis of the analyzer The direction of the reflected light intensity of the sample to be tested is obtained according to the reflected light intensity distribution of the sample to be tested, and the reflected light of the sample to be tested is fitted by a modified Jones model The intensity distribution curve is used to determine the anisotropy of the sample to be tested. The anisotropic measurement method according to claim 8, wherein the modified Jones operation model includes a correction matrix to correct the error caused by the non-polarization beam splitter and the objective lens. The method for determining an anisotropic measurement method according to Item 8 of the patent application, wherein the step of determining a reflected light intensity distribution curve of the sample to be tested according to the reflected light intensity distribution map of the sample to be tested further comprises: reflecting light intensity at the sample to be tested Selecting a center point on the distribution map; forming an inner circle on the reflected light intensity distribution map of the sample to be measured by using the center point as a center and a first length as a radius, and the center point is a center and a first The second length is a circle drawn to form an outer circle; the complex line is connected to the point on the outer circle; and when the light intensity indicated by the line is lower than a critical value from the inside to the outside, The position where the critical value is located is a complex boundary point; and fitting the boundary points to obtain a fitted circle of the sample to be tested and a reflected light intensity distribution curve of the sample to be tested. The anisotropic measurement method according to claim 8, wherein the polarizer is a radial polarizer, the analyzer is an all-direction analyzer, and the first penetration axis The direction is radial and the direction of the second transmission axis is tangential. The anisotropic measurement method according to claim 8, wherein the polarizer is a radial polarizer, and the analyzer is a linear analyzer, and The direction of the first transmission axis is radial, and the direction of the second transmission axis is Y direction. The anisotropic measurement method according to claim 8, wherein the polarizer is a linear polarizer, the analyzer is a linear analyzer, and the direction of the first transmission axis is X. Direction, the direction of the second penetration axis is the Y direction. The anisotropic measurement method according to claim 8, wherein the polarizer is a linear polarizer, and the analyzer is a linear analyzer, and the linear polarizer surrounds a first light. The shaft rotates 360 degrees, the linear analyzer rotates 360 degrees around a second optical axis and rotates 360 degrees synchronously with the linear analyzer, wherein the first optical axis is the Z direction and the second optical axis is the X direction. And the starting direction of the first transmission axis is the X direction, and the starting direction of the second transmission axis is the Y direction. An anisotropic measuring method comprising: converting a polarization direction of an incident light into a direction of a first transmission axis of the polarizer by a linear polarizer, the linear polarizer winding around a first light The shaft rotates 360 degrees; the incident light partially penetrates the non-polarization beam splitter to form a portion of the incident light by a non-polarization beam splitter; the incident light is focused by an objective lens to a sample to be tested and received from the object The sample to be tested has one of the elliptically polarized light and is output parallel to the non-polarizing beam splitter; Receiving, by a linear analyzer, the reflected light reflected from the non-polarization beam splitter and generating an output light, wherein a polarization direction of the output light is converted into a direction of a second transmission axis of the analyzer, The linear analyzer rotates 360 degrees around a second optical axis and rotates 360 degrees synchronously with the linear analyzer; and determines a reflected light intensity distribution map of the sample to be tested according to the shape of the output light a reflected light intensity distribution curve of the sample; and determining a relative size of the anisotropy according to different amplitudes of the reflected light intensity distribution curves of the sample to be tested. The anisotropic measurement method according to claim 15, wherein the first optical axis is a Z direction and the second optical axis is an X direction, and a starting direction of the first transmission axis is an X direction. The starting direction of the second transmission axis is the Y direction. A method for correcting an anisotropic measurement method according to claim 8 of the patent application, comprising: obtaining a standard sample reflected light intensity distribution pattern whose shape is approximately a circle; and determining a reflected light intensity distribution according to the standard sample The figure obtains a reflected light intensity distribution curve of a standard sample; and fits the reflected light intensity distribution curve of the standard sample by a Jones operation model to obtain a correction matrix. The method of claim 17, wherein the step of determining the reflected light intensity distribution curve of the standard sample according to the reflected light intensity distribution map of the standard sample further comprises: selecting one of the reflected light intensity distribution maps of the standard sample; a center point; on the reflected light intensity distribution map of the standard sample, a circle is formed by centering the center point and a radius of the first length, and forming an inner circle with the center point as a center and a second length as a radius And forming an outer circle; making a complex line connecting the center point and the point on the outer circle; when the light intensity indicated by the line is lower than a critical value from the inside to the outside, the position where the threshold value is defined is Complex boundary points; and fitting the boundary points to obtain a standard sample fit circle and the standard sample reflected light intensity distribution curve. An anisotropic measuring system comprising: a linear polarizer that converts a polarization direction of an incident light into a direction of a first transmission axis of the linear polarizer, wherein the linear polarizer Rotating 360 degrees around a first optical axis; a non-polarizing beam splitter having a penetrating reflecting surface that partially penetrates the penetrating reflecting surface to form a portion of incident light; an objective lens that receives the portion of the incident light The portion of the incident light is focused to a sample to be tested, and received from the sample having the elliptically polarized light reflected from the sample to be tested and then incident parallel to the penetrating reflecting surface; a linear analyzer that receives the reflected light reflected from the penetrating reflecting surface and generates an output light whose polarization direction is converted into a second transmission axis direction of the linear analyzer, wherein the linearity The analyzer rotates 360 degrees around a second optical axis and rotates 360 degrees synchronously with the linear analyzer; an image detector receives the output light and generates a reflected light intensity distribution of the sample to be measured in a shape similar to a circle And an arithmetic processor that extracts a reflected light intensity distribution curve of the sample to be tested from a position on the reflected light intensity distribution map of the sample to be tested, and according to the different test sample to be tested The magnitude of the amplitude of the reflected light intensity distribution curve of the sample is used to determine the relative size of the anisotropy. The anisotropic measuring system according to claim 19, wherein the first optical axis is a Z direction and the second optical axis is an X direction, and a starting direction of the first transmission axis is an X direction. The starting direction of the second transmission axis is the Y direction.