JP2012243929A - Inspection method and device of polycrystalline silicon thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inspect the state of crystal of a polycrystalline silicon thin film by observing the state of surface of the polycrystalline silicon thin film optically.SOLUTION: The substrate inspection unit in the inspection device of a polycrystalline silicon thin film comprises illumination means for irradiating a substrate having a polycrystalline silicon thin film formed on the surface with light, first imaging means for capturing the optical image of first first-order diffracted light generated in a first direction from the substrate irradiated with light by the illumination means, second imaging means for capturing the optical image of second first-order diffracted light generated in a second direction from the substrate irradiated with light by the illumination means, and signal processing/determination means for determining the state of crystal of a polycrystalline silicon film formed on the substrate by processing a signal obtained by capturing the optical image of first first-order diffracted light by the first imaging means, and a signal obtained by capturing the optical image of second first-order diffracted light by the second imaging means.

Description

The present invention relates to a method and apparatus for inspecting a crystal state of a polycrystalline silicon thin film obtained by polycrystallizing amorphous silicon formed on a substrate by laser annealing.

Thin film transistors (TFTs) used for liquid crystal display elements and organic EL elements are polycrystallized by annealing a part of amorphous silicon formed on a substrate at low temperature with an excimer laser in order to ensure high-speed operation. Is formed.

As described above, when a part of amorphous silicon is annealed at a low temperature with an excimer laser to be polycrystallized, it is required to uniformly polycrystallize. In practice, however, the crystal varies due to the influence of the fluctuation of the laser light source. May occur.

Therefore, as a method of monitoring the occurrence state of the variation of the silicon crystal, Patent Document 1 discloses that the semiconductor film is irradiated with a pulse laser to perform laser annealing and the laser irradiation region is irradiated with inspection light, and the irradiated inspection light is irradiated. It is described that the reflected light from the substrate is detected and the state of crystallization of the semiconductor film is confirmed from the intensity change of the reflected light.

In Patent Document 2, the amorphous silicon before the laser irradiation is irradiated with the inspection light and the reflected light or the transmitted light is detected, and the inspection light is emitted even during the irradiation of the laser to the amorphous silicon. Irradiate and detect the reflected or transmitted light, and return to the intensity of the reflected or transmitted light before the laser irradiation from the time when the difference in intensity between the reflected light or transmitted light before the laser irradiation and during the laser irradiation becomes maximum It is described that the time of the laser annealing is detected to monitor the state of laser annealing.

Further, Patent Document 3 irradiates a region where amorphous silicon formed on a substrate is changed into polycrystalline silicon by excimer laser annealing with visible light from a direction of 10 to 85 degrees with respect to the substrate surface. It is described that reflected light is detected by a camera grounded in the same angle range as that of irradiation, and the arrangement state of protrusions on the crystal surface is inspected from the change of the reflected light.

Further, in Patent Document 4, a polycrystalline silicon thin film formed by irradiating an excimer laser on an amorphous silicon film is irradiated with inspection light, and diffracted light from the polycrystalline silicon thin film is monitored by a diffracted light detector. By utilizing the fact that the intensity of diffracted light generated from a region with a regular fine concavo-convex structure with high crystallinity of a silicon thin film is higher than the intensity of diffracted / scattered light from a region with low crystallinity, a polycrystalline silicon thin film It is described that the state of the test is inspected.

JP 2002-305146 A Japanese Patent Laid-Open No. 10-144621 JP 2006-19408 A JP 2001-308209 A

It is known that the surface of a polycrystalline silicon thin film (polysilicon film) formed by annealing an amorphous silicon thin film by irradiating it with an excimer laser is generated with a period having fine irregularities. These fine protrusions reflect the degree of crystallinity of the polycrystalline silicon thin film, and there are fine irregularities on the surface of the polycrystalline silicon thin film having a uniform crystalline state (with a uniform polycrystalline grain size). It is formed periodically with a certain regularity and the uniformity of the crystalline state is low (
It is known that fine irregularities are irregularly formed on the surface of a polycrystalline silicon thin film (which has an uneven polycrystalline grain size).

As described above, as a method for inspecting the surface state of the polycrystalline silicon thin film in which the crystal state is reflected in the reflected light, Patent Document 1 discloses that the intensity of the reflected light of the light irradiated to the laser annealed region is changed from that of the semiconductor film. It only describes that the state of crystallization is confirmed, but does not describe detecting diffracted light that reflects the state of crystal.

Patent Document 2 monitors the progress of annealing by comparing the reflected light from the laser irradiation region during laser annealing with the reflected light before annealing. There is no description about detecting the diffracted light in which is reflected.

On the other hand, Patent Document 3 describes that the quality of polycrystalline silicon crystal is inspected by the change of light reflected by the arrangement of protrusions on the surface of the polycrystalline silicon thin film formed by laser annealing. There is no description about detecting diffracted light generated by protrusions on the surface of the silicon thin film.

Further, Patent Document 4 describes the detection of diffracted light generated by protrusions on the surface of a polycrystalline silicon thin film formed by laser annealing, but the intensity level of diffracted light detected by a diffracted light detector. Is used to inspect the state of the polycrystalline silicon film, and to detect the image of the surface of the polycrystalline silicon thin film and observe the state of the protrusion on the surface of the polycrystalline silicon thin film. It has not been.

The object of the present invention is to solve the above-mentioned problems of the prior art, detect an image of the surface of the polycrystalline silicon thin film, observe the surface state of the polycrystalline silicon thin film, and determine the crystalline state of the polycrystalline silicon thin film. An object of the present invention is to provide a method and apparatus for inspecting a thin polycrystalline silicon thin film that enables inspection.

  In order to solve the above-described problems, in the present invention, in a polycrystalline silicon thin film inspection apparatus including a substrate loading unit, a substrate inspection unit, a substrate unloading unit, and an overall control unit, The first illuminating means for irradiating the substrate having the polycrystalline silicon thin film with the first wavelength light from the first direction and the first illuminating means on the substrate were irradiated with the first wavelength light. The second illuminating means for irradiating the region with the second wavelength light from the second direction, and the first illuminating means and the second illuminating means are irradiated with the first wavelength light and the second wavelength light. The first imaging means for capturing an optical image of the first first-order diffracted light by the light of the first wavelength generated in the third direction from the formed substrate, and the first illumination means and the second illumination means The second wave generated in the fourth direction from the substrate irradiated with the light of the first wavelength and the light of the second wavelength Second image pickup means for picking up an optical image of the second first-order diffracted light by the first light, a signal obtained by picking up the optical image of the first first-order diffracted light by the first image pickup means, and the second image pickup means And a signal processing / determination means for processing a signal obtained by picking up an optical image of the second first-order diffracted light and determining a crystal state of the polycrystalline silicon film formed on the substrate. .

  In order to solve the above-described problems, in the present invention, in a polycrystalline silicon thin film inspection apparatus including a substrate loading unit, a substrate inspection unit, a substrate unloading unit, and an overall control unit, a substrate inspection unit is provided. Illuminating means for irradiating light onto a substrate having a polycrystalline silicon thin film formed on the surface, and an optical image of the first first-order diffracted light generated in the first direction from the substrate irradiated with light by the illuminating means First imaging means, second imaging means for imaging an optical image of second first-order diffracted light generated in the second direction from the substrate irradiated with light by the illumination means, and first imaging means A signal obtained by picking up an optical image of the first primary diffracted light and a signal obtained by picking up an optical image of the second primary diffracted light by the second image pickup means are processed on the substrate. Signal processing / determination means for determining the crystal state of the crystalline silicon film. It was.

  Furthermore, in order to solve the above-described problems, the present invention provides a method for inspecting a polycrystalline silicon thin film by irradiating a substrate having a polycrystalline silicon thin film on the surface with light having a first wavelength from a first direction. Then, the region of the substrate irradiated with the light of the first wavelength is irradiated with the light of the second wavelength from the second direction, and from the substrate irradiated with the light of the first wavelength and the light of the second wavelength An optical image of the first first-order diffracted light by the light of the first wavelength generated in the third direction is picked up, and the fourth direction from the substrate irradiated with the light of the first wavelength and the light of the second wavelength An optical image of the second first-order diffracted light by the light of the second wavelength generated in the image is captured, and a signal obtained by capturing the optical image of the first first-order diffracted light and the optical image of the second first-order diffracted light are The signal obtained by imaging was processed to determine the crystal state of the polycrystalline silicon film formed on the substrate.

  Furthermore, in order to solve the above-described problems, the present invention provides a method for inspecting a polycrystalline silicon thin film by irradiating light onto a substrate having a polycrystalline silicon thin film formed on the surface, and then irradiating the substrate with the light. An optical image of the first first-order diffracted light generated in the first direction is picked up, an optical image of the second first-order diffracted light generated in the second direction is picked up from the substrate irradiated with the light, and the first Of the polycrystalline silicon film formed on the substrate by processing the signal obtained by imaging the optical image of the first-order diffracted light and the signal obtained by imaging the optical image of the second-order first-order diffracted light Judgment was made.

In order to solve the above-described problems of the prior art, in the present invention, a polycrystalline silicon thin film inspection apparatus is provided on an optically transparent substrate having a polycrystalline silicon thin film formed on one surface. Light irradiating means for irradiating light from the side, and light emitted from one side of the substrate by the light irradiating means through the substrate and the polycrystalline silicon thin film and emitted to the other side of the substrate An imaging unit that captures an image of the first-order diffracted light generated on the other surface side, and an image that inspects the crystal state of the polycrystalline silicon thin film by processing the image of the first-order diffracted light captured by the imaging unit Optically transparent comprising a processing means and an output means for displaying on the screen together with information on the result of inspection of the image of the first-order diffracted light processed by the image processing means, and having a polycrystalline silicon thin film formed on the surface Light from one side of the board to the correct board Irradiation and primary light generated on the other surface side by light emitted from the one surface side of the substrate through the substrate and the polycrystalline silicon thin film and emitted to the other surface side of the substrate The image of the folded light is picked up, the image of the first-order diffracted light obtained by imaging is processed to inspect the crystal state of the polycrystalline silicon thin film, and the processed first-order diffracted light image is inspected on the screen together with information on the result of the inspection. Displayed.

  According to the present invention, the suitability of the energy of the excimer laser irradiated at the time of annealing can be easily determined from the crystal state of the polycrystalline silicon thin film formed by annealing with the excimer laser. Moreover, it became possible to maintain the quality of the glass substrate for liquid crystal display panels highly by controlling irradiation energy based on the determined result.

It is a graph which shows the relationship between the irradiation energy of an excimer laser, and the crystal grain diameter of a polycrystalline silicon thin film. It is the top view of the polycrystalline silicon thin film which showed typically the state of the polycrystalline silicon thin film formed when the irradiation energy of an excimer laser is small. It is the top view of the polycrystalline silicon thin film which showed typically the state of the polycrystalline silicon thin film formed when the irradiation energy of an excimer laser is appropriate. It is the top view of the polycrystalline silicon thin film which showed typically the state of the polycrystalline silicon thin film formed when the irradiation energy of an excimer laser was too large. It is a block diagram which shows the schematic structure of the optical system which irradiates illumination light to the board | substrate with which the polycrystalline-silicon thin film was formed, and detects 1st-order diffracted light. It is a graph which shows the relationship between the irradiation energy of an excimer laser, and the brightness | luminance of the 1st-order diffracted light which generate | occur | produces from a polycrystalline-silicon thin film when irradiated with illumination light. It is a graph which shows the relationship between the irradiation energy of an excimer laser, and the brightness | luminance of the 1st-order diffracted light detected by a different detection angle when irradiated with illumination light. 6 is a graph showing a relationship between EV (x) obtained from two characteristic curves shown in FIG. 5 and excimer laser irradiation energy. It is a block diagram explaining the schematic structure of the whole inspection apparatus. FIG. 3 is a block diagram illustrating a schematic configuration of an inspection unit according to the first embodiment. 3 is a flowchart showing an imaging sequence for imaging a substrate in order to inspect the crystal state of the polycrystalline silicon thin film in Example 1. FIG. It is a flowchart which shows the sequence of the image processing which processes the image acquired in order to test | inspect the state of the crystal | crystallization of the polycrystalline silicon thin film in Example 1, and detects a defective part. It is a front view of the screen which outputs the test result of the test | inspection unit in Example 1. FIG. It is the figure which displayed the irradiation energy intensity distribution of the excimer laser of the whole board | substrate displayed on the board | substrate whole distribution display area 1103 of the screen which outputs the test | inspection result of the test | inspection unit in Example 1 in the matrix form. FIG. 6 is a diagram illustrating an example in which an area exceeding a threshold is displayed among the excimer laser irradiation energy intensity of the entire substrate displayed in the entire substrate distribution display area 1103 of the screen for outputting the inspection result of the inspection unit in the first embodiment. is there. 6 is a block diagram illustrating a schematic configuration of an illumination optical system in Embodiment 2. FIG. FIG. 10 is a block diagram illustrating a schematic configuration of an inspection unit according to a third embodiment.

As an embodiment of the present invention, an example applied to an apparatus for inspecting a polycrystalline silicon thin film formed on a glass substrate for a liquid crystal display panel will be described.

  A glass substrate for a liquid crystal display panel to be inspected (hereinafter referred to as a substrate) has an amorphous silicon thin film formed on the substrate. By irradiating the excimer laser to a part of the thin film of the amorphous silicon and scanning, the portion of the amorphous silicon irradiated with the excimer laser is heated and melted (annealed), and after the excimer laser is scanned, The molten amorphous silicon is gradually cooled to be polycrystallized, and crystals grow in the state of polycrystalline silicon.

  The graph of FIG. 1 shows an approximate relationship between the excimer laser irradiation energy and the crystal grain size of polycrystalline silicon when amorphous silicon is annealed with an excimer laser. When the irradiation energy of the excimer laser during annealing is increased, the crystal grain size of polycrystalline silicon also increases.

  When the irradiation energy of the excimer laser at the time of annealing is weak (range A in FIG. 1), as shown in FIG. 2A, the grain size of the crystal 201 of the polycrystalline silicon film is small and the variation is large. . In such a crystalline state, stable characteristics cannot be obtained as a polycrystalline silicon film.

  On the other hand, when the energy of the excimer laser at the time of annealing is set to an appropriate range (range B in FIG. 1), a polycrystalline silicon film having a relatively uniform grain size of crystals 202 is formed as shown in FIG. 2B. The Thus, when the film is obtained in a state where the crystal grain sizes are uniform, stable characteristics as a polycrystalline silicon film can be obtained.

  When the irradiation energy of the excimer laser at the time of annealing is further increased (range C in FIG. 1), the crystal grain size of polycrystalline silicon becomes larger. However, when the irradiation energy is increased, the variation in the growth rate of crystal grains increases, and as shown in FIG. 2C, the crystal 203 has a large variation in grain size, resulting in stable characteristics as a polycrystalline silicon film. Can't get.

  Accordingly, it is important to stably maintain the energy of the excimer laser irradiated to the amorphous silicon within the range of B in FIG.

  On the other hand, as described in Patent Document 3, it is known that a minute projection is formed at a crystal grain boundary in a polycrystalline silicon film formed by annealing amorphous silicon with an excimer laser.

  When the glass substrate 10 on which such a polycrystalline silicon film 301 is formed is irradiated with light from a light source 310 disposed on the back side as shown in FIG. 3, it is scattered by the minute protrusions 302 at the crystal grain boundaries of the polycrystalline silicon film 301. The diffracted light is generated on the surface side of the glass substrate 10 by the emitted light. The position where the diffracted light is generated varies depending on the wavelength of light emitted from the light source 310 and the pitch of the minute protrusions 302 formed at the crystal grain boundaries of the polycrystalline silicon film 301.

In the configuration shown in FIG. 3, the wavelength of the light that irradiates the substrate 300 is λ, the pitch of the minute protrusions 302 formed at the crystal grain boundaries of the polycrystalline silicon film 301 is P, and the substrate 300 of the light that irradiates the substrate 300. Θi is the angle from the normal direction, and θo is the angle from the normal direction of the substrate 300 of the first-order diffracted light generated from the substrate 300.
sinθi + sinθo = λ / P (Equation 1)
This relationship holds.

  Therefore, it is generated by light having a wavelength λ emitted from the light source 310 and irradiated from the direction of the angle θi in a state where minute protrusions 302 are formed at a predetermined pitch P in the crystal grain boundary of the polycrystalline silicon film 301. By observing the first-order diffracted light with the imaging camera 320 disposed at the angle θo, the first-order diffracted light from the polycrystalline silicon film 301 can be observed.

  On the other hand, the crystal grain size of the polycrystalline silicon film 301 depends on the excimer laser irradiation energy at the time of annealing as shown in FIG. 1, and in the region where the excimer laser irradiation energy of FIG. The crystal grain size increases as the excimer laser irradiation energy increases. Therefore, if the irradiation energy of the excimer laser varies during annealing, the crystal grain size of the polycrystalline silicon film 301 changes and the variation in grain size increases as described with reference to FIGS. 2A to 2C. When light is emitted from the light source 310 to the polycrystalline silicon film 301 in which the crystal grain size has changed and the pitch variation of the minute protrusions 302 has increased, the progression of the first-order diffracted light generated from the polycrystalline silicon film 301 When the direction changes, the intensity mainly decreases, so the luminance of the first-order diffracted light detected by the imaging camera 320 decreases.

  As described above, the phenomenon that the luminance of the first-order diffracted light decreases and the detection intensity of the first-order diffracted light by the imaging camera 320 decreases as shown in FIG. When the crystal grain size of the polycrystalline silicon film 301 increases as a whole, and when the irradiation energy of the excimer laser during annealing fluctuates in a smaller direction, the crystal grain size of the polycrystalline silicon film 301 decreases as a whole. It occurs in the same way.

  Therefore, it is difficult to determine whether the polycrystalline silicon film 301 is in a large or small crystal grain size only by the detection intensity signal of the first-order diffracted light from the imaging camera 320.

  In order to solve this, as shown in FIG. 5, two detection systems having different detection characteristics with respect to the diffracted light from the minute projections 302 of the polycrystalline silicon film 301 are provided, and the outputs of the respective detection systems are provided. It is only necessary to detect the change in the crystal grain size of the polycrystalline silicon film 301 by using it.

That is, as shown in FIG. 5, the irradiation energy of the excimer laser at the time of annealing is set to x, a plurality of actual measurement values are obtained, and the first detection system obtained on the assumption that they have a quadratic function distribution is obtained. The detection characteristic is f (x), the detection characteristic of the second detection system is g (x),
f (x) = a (x−α) ² + b
Here, a and b are constants, and α is an x value when f (x) is maximum.
g (x) = c (x−β) ² + d
Here, c and d are constants, and β is an x value when g (x) is maximum.
Where EV (x) is defined as follows as a synthesis function of f (x) and g (x).
EV (x) = − cf (x) + ag (x)
= -2ac (β-α) x + ac (β ² -α ² ) + c (d−b) (Equation 2)
That is, EV (x) can be expressed as a linear function of x. For example, as shown in FIG. 6, EV (x) is obtained by detecting f (x) and g (x). The irradiation energy x of the excimer laser can be uniquely determined.

In the present invention, an image of diffracted light generated by minute projections on the surface of the film is illuminated by illuminating the polycrystalline silicon thin film, and the image of the diffracted light obtained by processing the image is processed, so that polycrystalline silicon is formed on the substrate. It is an object of the present invention to provide a method and apparatus for evaluating the crystal state of a polycrystalline silicon thin film by examining whether or not the thin film is formed as a normal film having a uniform crystal grain size.
Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 7 shows the overall configuration of a polycrystalline silicon thin film inspection apparatus 700 for a glass substrate for a liquid crystal display panel according to the present invention.

  The polycrystalline silicon thin film inspection apparatus 700 includes a substrate loading unit 710, an inspection unit 720, a substrate unloading unit 730, an inspection unit data processing / control unit 740, and an overall control unit 750.

  A glass substrate (hereinafter referred to as a substrate) 300 for a liquid crystal display panel to be inspected irradiates an excimer laser to an amorphous silicon thin film formed on the glass substrate 303 in a part of the region immediately before this inspection step. Then, the heated region is annealed and crystallized from the amorphous state by scanning and heating, so that the polycrystalline silicon thin film 301 is obtained as shown in FIG. The polycrystalline silicon thin film inspection apparatus 700 images the surface of the substrate 300 and examines whether or not the polycrystalline silicon thin film 301 is normally formed.

  The substrate 300 to be inspected is set on the load unit 710 by a transfer means (not shown). The substrate 300 set on the load unit 710 is transported to the inspection unit 720 by a transport unit (not shown) controlled by the overall control unit 750. The inspection unit is provided with an inspection unit 721, which is controlled by the inspection data processing / control unit 740 to inspect the state of the polycrystalline silicon thin film formed on the surface of the substrate 300. The data detected by the inspection unit 721 is processed by the inspection data processing / control unit 740 to evaluate the state of the polycrystalline silicon thin film 301 formed on the surface of the substrate 300.

  The substrate 300 that has been inspected is transferred from the inspection unit 720 to the unload unit 730 by a transfer unit (not shown) controlled by the overall control unit 750, and taken out from the inspection apparatus 700 by a handling unit (not shown). 7 shows a configuration in which one inspection unit 721 is provided in the inspection unit 720, but it depends on the size of the substrate 300 to be inspected and the area and arrangement of the formed polycrystalline silicon thin film 301. The number may be two or three or more.

The configuration of the inspection unit 721 in the inspection unit 720 is shown in FIG.
The inspection unit 721 includes an illumination optical system 810, an imaging optical system 820, a substrate stage unit 830, and an inspection unit data processing / control unit 840. The inspection unit data processing / control unit 840 is the overall control shown in FIG. Part 750.

  The illumination optical system 810 includes a first light source 811 that emits light having a first wavelength λ1, a first mirror 812 that converts an optical path of light having a first wavelength λ1 emitted from the first light source 811, a first mirror 812, The first cylindrical lens that collects the light of the first wavelength λ 1 whose optical path is converted by one mirror 812, forms the light into a linear light, and irradiates the glass substrate 300 held by the substrate stage unit 830. 813, a second light source 814 that emits light of a second wavelength λ2 that is longer than the light of the first wavelength λ1, and an optical path of light of the second wavelength λ2 emitted from the second light source 814 The second mirror 815 to be converted, and the glass substrate held by the substrate stage unit 830 by condensing the light having the second wavelength λ 2 whose optical path has been converted by the second mirror 815 and forming it into linear light A region irradiated with light having a first wavelength λ1 of 300 is illuminated. And a second cylindrical lens 816 for projecting.

  The light having the first wavelength λ1 and the light having the second wavelength λ2 are light having a wavelength in the range of 300 nm to 700 nm. For the first light source 811 and the second light source 814, for example, laser diodes are used. .

  The first cylindrical lens 813 adjusts the light of the first wavelength λ 1 emitted from the first light source 811 and converted in the optical path by the first mirror 812 to the size of the inspection region on the substrate 300. In order to illuminate efficiently, the illumination light beam is condensed in one direction to form a linear shape having a long cross section in one direction. By irradiating the substrate 300 with light condensed in one direction by the first cylindrical lens 813 from an angle direction θ1 with respect to the normal direction, the amount of illumination light in the inspection region on the substrate 300 is increased, and imaging optics The system 820 can detect images with higher contrast.

  The second cylindrical lens 816 also emits light of the second wavelength λ 2 emitted from the second light source 814 and having its optical path converted by the second mirror 815 by the first cylindrical lens 813 on the substrate 300. The illumination light beam is condensed in one direction so as to efficiently illuminate in accordance with the inspection region irradiated with the light having the wavelength λ1, and the cross-sectional shape is formed into a linear shape that is long in one direction. By irradiating the substrate 300 with the light condensed in one direction by the second cylindrical lens 816 from the angle direction θ2 with respect to the normal direction, the amount of illumination light in the inspection region on the substrate 300 increases, and the imaging optics The system 820 can detect images with higher contrast.

  The imaging optical system 820 is generated from the first wavelength selection filter 821 that selectively transmits light having the first wavelength and the substrate 300 that is generated by the light having the first wavelength that has passed through the first wavelength selection filter 821. A first camera 823 including a first imaging lens system 822 that captures an image by the next diffracted light, a second wavelength selection filter 824 that selectively transmits light of the second wavelength, and a second wavelength selection And a second camera 826 including a second imaging lens system 825 that captures an image of the first-order diffracted light generated from the substrate 300 by the light of the second wavelength that has passed through the filter 824.

  The wavelength selection filter 821 selectively transmits light having the first wavelength among the diffracted light from the substrate 300, and cuts light having a wavelength other than the light having the first wavelength from the substrate 300 and its periphery. be able to.

  The wavelength selection filter 823 also selectively transmits light having the second wavelength out of the diffracted light from the substrate 300, and cuts light having a wavelength other than the light having the second wavelength from the substrate 300 and its periphery. be able to.

  The first camera 823 is installed in an angular direction inclined by θ3 with respect to the normal direction of the substrate 300. The first camera 823 is a crystal grain boundary of the polycrystalline silicon thin film 301 existing in a long region in one direction of the surface of the substrate 300 illuminated with the light of the first wavelength λ 1 formed by the first cylindrical lens 813. An optical image is picked up by the first-order diffracted light from the minute protrusions 302 formed at the pitch P1. The first camera 823 is a one-dimensional CCD (electrically coupled device) image sensor (not shown) or a two-dimensional CCD image sensor arranged in accordance with an image of a long region illuminated in one direction of the substrate 300. (Not shown).

  That is, the tilt angle θ3 of the first camera 823 is determined by the pitch P1 of the microprojections 302 at the grain boundaries of the polycrystalline silicon thin film 301, the wavelength λ1 of the first wavelength light, and the substrate of the first wavelength light. It is determined based on the relationship of Equation 1 by the incident angle θ1 to 300. Determined.

  The second camera 826 is installed in an angle direction inclined by θ4 with respect to the normal direction of the substrate 300. The second camera 826 has a pitch P2 at the grain boundary of the polycrystalline silicon thin film 301 existing in a long region in one direction of the surface of the substrate 300 illuminated with light of the second wavelength λ2 by the second cylindrical lens 816. The optical image by the 1st-order diffracted light from the microprotrusion 302 formed in (1) is taken. The second camera 826 is a one-dimensional CCD (electrically coupled device) image sensor (not shown) or a two-dimensional CCD image sensor (not shown) arranged in accordance with a long illuminated area of the substrate 300. (Not shown).

  In other words, the tilt angle θ4 of the second camera 826 includes the pitch P2 of the microprotrusions 302 at the grain boundaries of the polycrystalline silicon thin film 301, the wavelength λ2 of the second wavelength light, and the substrate of the second wavelength light. It is determined based on the relationship of Equation 1 depending on the incident angle θ <b> 2 to 300.

  At this time, the wavelength λ1 of the first wavelength light is made shorter than the wavelength λ2 of the second wavelength light, the pitch P1 of the microprojections 302 is made smaller than the pitch P2 of the microprojections 302, and the first When the incident angle θ1 of the light having the wavelength on the substrate 300 is set larger than the incident angle θ2 of the light having the second wavelength on the substrate 300, the inclination angle θ3 of the first camera 823 becomes the inclination angle of the second camera 826. It can be set sufficiently smaller than θ4, and the first camera 823 and the second camera 826 can be installed above the substrate stage 831 without interfering with each other.

  In addition, the first camera 823 is installed at a position for detecting the first-order diffracted light from the minute protrusion 302 with the pitch P1, and the second camera 826 is installed at a position for detecting the first-order diffracted light from the minute protrusion 302 with the pitch P2. By doing so, two characteristic curves having different peak positions as shown in FIG. 5 can be obtained from the detection signals of the respective cameras, and the relationship of the linear function EV (x) as shown in FIG. 6 is obtained. be able to.

  The substrate stage unit 830 places and holds the inspection target substrate 300 on the upper surface of the stage 831 that can be moved in the XY plane by the driving means 832. As the drive means 832, for example, a servo motor provided with a stepping motor or a rotary encoder may be used.

The inspection data processing / control unit 840 converts an analog image signal output from the first camera 823 into a digital image signal, and converts the analog image signal output from the second camera 826 into a digital image. A digital image signal A / D converted by the A / D conversion unit 842, A / D conversion unit 841 and A / D conversion unit 842 to be converted into signals is calculated using (Equation 1) on the substrate 300. The calculation unit 843 for calculating the energy of the excimer laser irradiated to the polycrystalline silicon thin film 301 and the processing determination unit 844 for obtaining and imaging the distribution of the irradiation energy of the excimer laser for each region on the substrate 300 by the calculation unit 843. , An input / output unit 845 including a display unit 8451 for displaying a result processed by the processing determination unit 844, a power source unit 846 of the first light source 811 and the second light source 814, and a substrate stage unit. A drive unit control unit 847 that controls the 30 drive units 832; and a control unit 848 that controls the calculation unit 843, the process determination unit 844, the output unit 845, the power supply unit 846, and the drive unit control unit 847. .
The control unit 847 is connected to the overall control unit 750.

  With such a configuration, the illumination optical system 810 illuminates the substrate 300 placed on the substrate stage 831 from the back side, and the imaging optical system 820 captures an image of the first-order diffracted light generated by the light transmitted through the substrate 300. The crystal state of the polycrystalline silicon thin film 301 formed on the substrate 300 is inspected by the inspection data processing / control unit 840.

  Next, a method of inspecting the state of the polycrystalline silicon thin film 301 that has been annealed with an excimer laser on the substrate 300 and made polycrystalline using the inspection unit 721 having the configuration shown in FIG. 8 will be described.

  First, the flow of processing for inspecting the inspection region of the polycrystalline silicon thin film 301 formed by annealing the excimer laser on the substrate 300 will be described. The inspection processing includes an imaging sequence for imaging a predetermined region or the entire surface of the substrate 300 and an image processing sequence for processing an image obtained by imaging and detecting a defective portion.

First, the imaging sequence will be described with reference to FIG.
First, the driving means 832 is driven by the driving means control unit 847 so that the inspection start position of the inspection region of the polycrystalline silicon thin film 301 falls within the field of view of the first camera 823 and the second camera 826 of the imaging optical system 820. The position of the substrate stage 831 is controlled to set the substrate 300 to the initial position (inspection start position) (S901).

Next, the power source control unit 846 controls the first light source 811 and the second light source 814, and the light having the first wavelength linearly formed by the first cylindrical lens 813 is incident at an incident angle of θ1. Then, the same region of the polycrystalline silicon thin film 301 on the substrate 300 is irradiated with the light of the second wavelength shaped linearly by the second cylindrical lens 816 at an incident angle of θ2 (S902). Driving means control so that the imaging area of the imaging optical system 820 moves along the inspection area of the polycrystalline silicon thin film 301 illuminated with the light of the first wavelength and the light of the second wavelength by the illumination optical system 810. The drive unit 832 is controlled by the unit 847 to start moving the substrate stage 831 at a constant speed (S903).
While moving the substrate stage 831 at a constant speed, the polycrystalline silicon thin film is linearly shaped by the first cylindrical lens 813 of the illumination optical system 810 and illuminated by the light having the first wavelength incident at the angle θ1. An optical image of the first-order diffracted light generated in the direction of θ 3 from the fine protrusion 302 of the crystal grain boundary in the inspection region 301 that is long in one direction is picked up by the first camera 823 via the wavelength selection filter 821. At the same time, an inspection region that is linearly shaped by the second cylindrical lens 816 of the illumination optical system 810 and is illuminated in a direction of the polycrystalline silicon thin film 301 that is illuminated by the second wavelength light incident at an angle of θ2. An optical image by the first-order diffracted light generated in the direction of θ4 from the microprojection 302 of the crystal grain boundary is picked up by the second camera 826 through the wavelength selection filter 824 (S904).

  A detection signal from the first camera 823 that has captured an optical image of the first-order diffracted light of the first wavelength light is input to the A / D conversion unit 841 of the inspection data processing / control unit 840 and A / D converted. Are input to the arithmetic processing unit 843. A detection signal from the second camera 826 that has captured an optical image of the first-order diffracted light of the second wavelength light is input to the A / D conversion unit 842 of the inspection data processing / control unit 840 and A / D converted. Are input to the arithmetic processing unit 843. The detection signal input to the arithmetic processing unit 843 is processed using the position information of the substrate stage 831 obtained through the driving unit control unit 847, and is based on the signal obtained by imaging with the first camera 823. A first digital image and a second digital image based on a signal obtained by imaging with the second camera 826 are created (S905). The above operation is repeatedly executed until the inspection for one line along the X direction or the Y direction is completed (S906).

Next, it is checked whether there is an inspection area adjacent to the area for one line that has been inspected (S9).
07) If there is an adjacent uninspected area, the substrate stage 831 is moved to the adjacent inspection area (S908), and the steps from S903 are repeated. When all the areas to be inspected are inspected, the movement of the XY table is stopped (S909), and the power source control unit 846 controls the first light source 811 and the second light source 814 to turn off the illumination (S910). End the sequence.

  Next, an image processing sequence for processing the first digital image and the second digital image obtained in the imaging sequence in S905 will be described with reference to FIG.

The first digital image and the second digital image created by the arithmetic processing unit 843 in the digital image creation step (S905) of the imaging sequence are input to the processing determination unit 844 (S1001), and the first digital image and the first digital image By combining the digital image of 2 (S1002) and processing the image signals corresponding to the first digital image and the second digital image using the arithmetic expression shown in (Expression 2), The irradiation energy of the excimer laser irradiated to the corresponding part of the silicon film 301 is calculated over a predetermined region of the substrate 300 (S1003),
It is determined over a predetermined region of the substrate 300 whether the calculated irradiation energy of the excimer laser is within a predetermined reference irradiation energy range, or larger or smaller (S1004).

  Next, based on the determination result over a predetermined region of the substrate 300, a map of the excimer laser irradiation energy intensity in the predetermined region of the substrate 300 is created and displayed on the display screen 8451 of the input / output unit 845. (S1005), the processing / determination sequence ends. On the map of excimer laser irradiation energy intensity displayed on this display screen 8451, an area determined to be defective as being larger or smaller than the reference irradiation energy range preset in S1004 can be distinguished from a normal area. Is displayed. In addition, when the determination criterion is changed by inputting from the input / output unit 845, the defective area is also changed and displayed corresponding to the changed defect criterion.

An example of the inspection result display screen 1100 displayed on the display unit 8451 is shown in FIG.
As shown in FIG. 11, the inspection result display screen 1100 includes a substrate designating unit 1101 for designating a display target substrate, an execution button 1102 for supporting execution of display of the designated substrate, and excimer laser irradiation of the entire designated substrate. An entire substrate distribution display area 1103 for displaying the energy intensity distribution, and an enlarged display designating means 1104 for designating an area to be magnified and displayed among the excimer laser irradiation energy intensity distributions of the entire substrate displayed on the entire substrate image display area 1103; An enlarged display area 1105 for enlarging and displaying the irradiation energy intensity distribution of the excimer laser in the area designated by the enlarged display designation means 1104 and an inspection result display unit 1106 for displaying the inspection result of the substrate are displayed on one screen. Is done.

  The image of the excimer laser irradiation energy intensity distribution of the entire substrate displayed in the entire substrate image display area 1103 is displayed with the result determined by the image processing / determination unit 844 being highlighted. That is, the area determined to be defective by the image processing / determination unit 844 as being larger or smaller than the reference irradiation energy range is displayed in a different color from the area determined to be normal.

  An example of the irradiation energy intensity distribution of the excimer laser displayed in the entire substrate distribution display area 1103 is shown in FIGS. 12A and 12B.

  FIG. 12A shows an example in which the entire substrate is divided into a matrix, and the irradiation energy of the excimer laser calculated in S1003 in each region is displayed in 256 tones according to the energy.

  Further, in FIG. 12B, based on the result determined in S1004, the region determined to be defective as being larger than the reference irradiation energy range and the region determined to be defective as being small are displayed so that they can be identified. An example is shown.

By inspecting with the above-described configuration, according to the first embodiment, the crystal state of the polycrystalline silicon thin film formed by annealing with the excimer laser can be inspected with relatively high accuracy, and the glass for a liquid crystal display panel It becomes possible to maintain the quality of the substrate high.

In the above description, a cylindrical lens 205 is used as the illumination optical system 200 to illuminate a long region in one direction on the substrate 1, but the same effect can be obtained by replacing this with a normal circular lens.

  In the first embodiment, two light sources that emit light having different wavelengths are used for the illumination optical system 810. However, in this embodiment, a single light source that emits light having a plurality of wavelengths is used as the light source. explain. Since the overall configuration of the polycrystalline silicon thin film inspection apparatus for the glass substrate for a liquid crystal display panel in Example 2 is the same as that described with reference to FIG. 7 in Example 1, detailed description thereof is omitted.

  In addition, the imaging optical system, the substrate stage unit, and the inspection data processing / control unit in the second embodiment are configured and their operations / operations are the same as the imaging optical system 820, the substrate stage unit 830, and the inspection data processing / control unit described in the first embodiment. Since this is the same as 840, description thereof is omitted.

  FIG. 13 shows the configuration of the illumination optical system 1310 in the present embodiment. The illumination optical system 1310 in the present embodiment includes a light source 1311 that emits light of a plurality of wavelengths including wavelengths λ1 and λ2, and a first dichroic mirror that reflects light of wavelength λ1 and transmits light of other wavelengths. 1312, the wavelength λ1 reflected by the second dichroic mirror 1313 reflecting the light of wavelength λ2 among the light transmitted through the first dichroic mirror 1312 and transmitting the light of other wavelengths, and the wavelength λ1 reflected by the first dichroic mirror 1312 812 for converting the optical path of the light of the light, and the light having the wavelength λ 1 whose optical path has been converted by the mirror 812 is condensed in one direction, shaped into a linear light, and normal to the substrate 300 held by the substrate stage 831 The optical path of the light of wavelength λ2 reflected by the first cylindrical lens 813 and the second dichroic mirror 1313 that irradiates from the direction of θ1 with respect to the direction is changed. The mirror 815 to be converted, and the light having the wavelength λ2 whose optical path is converted by the mirror 815 are condensed in one direction to form linear light, and the substrate 300 held by the substrate stage 831 has a θ2 with respect to the normal direction. A second cylindrical lens 816 for irradiating from the direction is provided.

  In the above configuration, light emitted from the light source 1311 is incident on the first dichroic mirror 1312, light having the wavelength λ <b> 1 is reflected, and light having other wavelengths is transmitted through the first dichroic mirror 1312. The light having the wavelength λ 1 reflected by the first dichroic mirror 1312 is incident on the mirror 812, totally reflected, converted in the optical path, and incident on the first cylindrical lens 813. The light having the wavelength λ1 incident on the first cylindrical lens 813 is focused in one direction and converged, and is shaped into a linear shape that does not converge in the other direction (direction perpendicular to the paper surface of FIG. 13). In the same manner as in the first embodiment, the light enters the substrate 300 held by the substrate stage 831 from the angle direction θ1 with respect to the normal direction.

  On the other hand, the light emitted from the light source 1311 and transmitted through the first dichroic mirror 1312 is incident on the second dichroic mirror 1313, the light of wavelength λ2 is reflected, and the light of other wavelengths is reflected by the second dichroic mirror 1313. Transparent. The light having the wavelength λ 2 reflected by the second dichroic mirror 1313 is incident on the mirror 815, totally reflected, converted into an optical path, and incident on the second cylindrical lens 816. The light of wavelength λ2 incident on the second cylindrical lens 816 is focused in one direction and converged, and is shaped into a linear shape that does not converge in the other direction (direction perpendicular to the paper surface of FIG. 13). Similar to the first embodiment, the region irradiated with the light of wavelength λ1 linearly formed by the first cylindrical lens 813 of the substrate 300 held by the substrate stage 831 is irradiated with respect to the normal direction. Incident from the angle direction of θ2.

  In this embodiment, an imaging sequence in which an image of the diffracted light generated from the substrate 300 irradiated with the light of wavelength λ1 and the light of wavelength λ2 is captured by the imaging optical system and the signal is processed by the inspection data processing / control unit, Since the image processing sequence is the same as that described in the first embodiment with reference to FIGS. 9 and 10, the description thereof is omitted.

  According to the present embodiment, since the illumination optical system can have a single light source, the illumination optical system can be designed in a compact manner.

  In the second embodiment, a single light source that emits light having a plurality of wavelengths including wavelengths λ1 and λ2 is used for the illumination optical system 1310, and light having a wavelength λ1 and light having a wavelength lambda 2 using two dichroic mirrors. In the present embodiment, a single light source that emits light having a plurality of wavelengths including wavelengths λ1 and λ2 has been described. An example of irradiating the substrate 300 with the light emitted from will be described with reference to FIG. Since the overall configuration of the polycrystalline silicon thin film inspection apparatus for the glass substrate for a liquid crystal display panel in Example 3 is the same as that described with reference to FIG. 7 in Example 1, the detailed description thereof is omitted.

  Further, in the configuration shown in FIG. 14, the same components as those shown in FIG. 8 described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. What differs from the configuration of the first embodiment is an illumination optical system 1410 and an imaging optical system 1420.

  Among these, the illumination optical system 1410 condenses the light source 1411 that emits light having a certain wavelength width, the mirror 812 that converts the optical path of the light emitted from the light source 1411, and the light whose optical path has been converted by the mirror 812. A glass substrate 300 formed into linear light and held on the substrate stage 831 is provided with a cylindrical lens 813 for irradiating from the direction of θ10 with respect to the normal direction.

  In addition, the imaging optical system 1420 is generated by minute protrusions generated in the crystal grain boundaries of the polycrystalline silicon thin film 301 on the glass substrate 300 irradiated with light having a certain wavelength width formed linearly by the cylindrical lens 813. Of the first-order diffracted light, the first wavelength selection filter 1421 that transmits the first-order diffracted light having a wavelength of λ1 that has traveled in the direction of the angle θ3 with respect to the normal direction, and the wavelength that has passed through the first wavelength selection filter 1421 A first camera 823 including a first imaging lens system 822 that captures an image of the first-order diffracted light having a wavelength of λ1. Of the first-order diffracted light generated by the minute protrusions, the first camera 823 has an angle θ4 with respect to the normal direction A second wavelength selection filter 1424 that transmits the first-order diffracted light having a wavelength of λ2 and an image of the first-order diffracted light having a wavelength of λ2 that has passed through the second wavelength selection filter 1424 are captured. And a second camera 826 provided with a second image-forming lens system 825 that.

  In the present embodiment, an imaging sequence and an image processing sequence in which detection signals from the first camera 823 and the second camera 826 are processed by the inspection data processing / control unit are shown in FIGS. Since it is the same as what was demonstrated using 10, description is abbreviate | omitted.

  According to the present embodiment, the illumination optical system can be designed more compactly than in the second embodiment.

  300 ... Substrate 700 ... Inspection device 720 ... Inspection unit 721 ... Inspection unit 740, 840 ... Inspection data processing / control unit 750 ... Overall control unit 810, 1310, 1410 ... Illumination optical system 811 ... First light source 814 ... Second Light source 813 ... First cylindrical lens 816 ... Second cylindrical lens 820, 1420 ... Imaging optical system 821 ... First wavelength selection filter 824 ... Second wavelength selection filter 822 ... First imaging lens 825 ... Second Imaging lens 823 ... 1st camera 826 ... 2nd camera 830 ... Substrate stage unit 831 ... Substrate stage 840 ... Image processing unit 841, 842 ... A / D conversion unit 843 ... Image generation unit 844 ... Processing / determination unit 845 ... Input / output unit 8451 ... Display screen 848 ... Control unit 1311, 1411 ... Light source 1312 ... First dichroic mirror 1313 ... Second dichroic mirror.

Claims (16)

A polycrystalline silicon thin film inspection apparatus including a substrate loading unit, a substrate inspection unit, a substrate unloading unit, and an overall control unit,
The board inspection unit
A first illumination means for irradiating light having a first wavelength from a first direction onto a substrate having a polycrystalline silicon thin film formed on a surface thereof;
A second illuminating means for irradiating light having a second wavelength from a second direction onto a region irradiated with the light having the first wavelength by the first illuminating means on the substrate;
By the light of the first wavelength generated in the third direction from the substrate irradiated with the light of the first wavelength and the light of the second wavelength by the first illumination means and the second illumination means. First imaging means for imaging an optical image of the first first-order diffracted light;
By the light of the second wavelength generated in the fourth direction from the substrate irradiated with the light of the first wavelength and the light of the second wavelength by the first illumination means and the second illumination means. Second imaging means for imaging an optical image of the second first-order diffracted light;
A signal obtained by imaging the optical image of the first first-order diffracted light with the first imaging means, and a signal obtained by imaging the optical image of the second first-order diffracted light with the second imaging means; And a signal processing / determination means for determining the crystal state of the polycrystalline silicon film formed on the substrate by processing the process.   The first illumination means includes a first light source unit that emits light of a first wavelength, and linearly collects light of the first wavelength emitted from the first light source unit in one direction. A second cylindrical light source that emits light having a second wavelength, and a second light source unit that emits light having a second wavelength. 2. The polycrystalline silicon according to claim 1, further comprising a second cylindrical lens that condenses the emitted light having the second wavelength in one direction, forms the light into linear light, and irradiates the substrate. Thin film inspection equipment.   The first illuminating unit and the second illuminating unit share a light source unit that emits multi-wavelength light including light of the first wavelength and light of the second wavelength, and The illuminating means includes a first dichroic mirror that reflects the light of the first wavelength among the multi-wavelength light emitted from the light source unit and transmits the light of other wavelengths, and the first dichroic mirror. A first cylindrical lens that collects the reflected light of the first wavelength in one direction, shapes the light into linear light, and irradiates the substrate; and the second illuminating unit includes: A second dichroic mirror that reflects the second wavelength light among the emitted multi-wavelength light that has passed through the first dichroic mirror, and transmits the other wavelength light; and The light of the second wavelength reflected by the dichroic mirror is collected in one direction. To linear polycrystalline silicon thin film inspecting apparatus according to claim 1, characterized in that it comprises a second cylindrical lens for irradiating molded into the substrate to light.   The first illuminating means and the second illuminating means are arranged such that the first direction is larger than the second direction with respect to the normal direction of the surface of the substrate, and the substrate The first imaging means and the second imaging means are arranged so that the third direction is smaller than the fourth direction with respect to the normal direction of the surface of The polycrystalline silicon thin film inspection apparatus according to claim 1.   5. The polycrystalline silicon thin film inspection apparatus according to claim 1, wherein the first wavelength light has a shorter wavelength than the second wavelength light. 6. A polycrystalline silicon thin film inspection apparatus including a substrate loading unit, a substrate inspection unit, a substrate unloading unit, and an overall control unit,
The board inspection unit
Illumination means for irradiating light onto a substrate having a polycrystalline silicon thin film formed on the surface;
First imaging means for imaging an optical image of first first-order diffracted light generated in a first direction from the substrate irradiated with light by the illumination means;
Second imaging means for imaging an optical image of second first-order diffracted light generated in a second direction from the substrate irradiated with light by the illumination means;
A signal obtained by imaging the optical image of the first first-order diffracted light with the first imaging means, and a signal obtained by imaging the optical image of the second first-order diffracted light with the second imaging means; And a signal processing / determination means for determining the crystal state of the polycrystalline silicon film formed on the substrate by processing the process.   The first imaging means includes a first wavelength selection filter that transmits light of the first wavelength and blocks light of other wavelengths, and has the first wavelength of light transmitted through the first wavelength selection filter. An optical image of the first first-order diffracted light is picked up by light, and the second image pickup means includes a second wavelength selection filter that transmits light of the second wavelength and blocks light of other wavelengths. 7. The polycrystalline silicon thin film inspection apparatus according to claim 6, wherein an optical image of the second first-order diffracted light is picked up by light having a second wavelength transmitted through the second wavelength selection filter.   The light of the first wavelength is shorter than the light of the second wavelength, and the first direction is smaller than the second direction with respect to the normal direction of the substrate. The polycrystalline silicon thin film inspection apparatus according to claim 7. A substrate having a polycrystalline silicon thin film formed on the surface is irradiated with light of a first wavelength from a first direction,
Irradiating the region of the substrate irradiated with the light of the first wavelength from the second direction with the light of the second wavelength;
Capturing an optical image of the first first-order diffracted light by the light of the first wavelength generated in the third direction from the substrate irradiated with the light of the first wavelength and the light of the second wavelength;
Capturing an optical image of the second first-order diffracted light by the light of the second wavelength generated in the fourth direction from the substrate irradiated with the light of the first wavelength and the light of the second wavelength;
Polycrystalline silicon formed on the substrate by processing a signal obtained by taking an optical image of the first first-order diffracted light and a signal obtained by taking an optical image of the second first-order diffracted light A method for inspecting a polycrystalline silicon thin film, comprising: determining a crystal state of a film.   The light having the first wavelength is irradiated from the first direction, and the light having the first wavelength emitted from the first light source unit is condensed in one direction by the first cylindrical lens to be linear light. The second wavelength emitted from the second light source unit is formed by irradiating the substrate from the first direction and irradiating the second wavelength light from the second direction. The polycrystalline silicon according to claim 9, wherein the light is condensed in one direction by a second cylindrical lens, shaped into linear light, and irradiated onto the substrate from the second direction. Thin film inspection method.   Light emitted from a light source unit that emits multi-wavelength light including light of the first wavelength and light of the second wavelength, irradiating the light of the first wavelength from the first direction. The light of the first wavelength reflected by the first dichroic mirror that reflects the light of the first wavelength is condensed in one direction by the first cylindrical lens, and shaped into a linear light. Irradiating the substrate from the first direction and irradiating the second wavelength of light from the second direction includes the first wavelength of light and the second wavelength of light. Of the light emitted from the light source that emits multi-wavelength light, the second wavelength lens reflects the second wavelength light reflected by the second dichroic mirror that reflects the second wavelength light. Condensed in the direction and shaped into a linear light, the substrate from the second direction Polycrystalline silicon thin film inspection method according to claim 9, wherein the performing by irradiation.   The first direction of irradiating the light of the first wavelength is an angular direction larger than the second direction with respect to the normal direction of the surface of the substrate, and the first direction by the light of the first wavelength 10. The third direction for capturing an optical image of the first-order diffracted light of 1 is an angle direction smaller than the fourth direction with respect to the normal direction of the surface of the substrate. Method for inspecting polycrystalline silicon thin film.   13. The method for inspecting a polycrystalline silicon thin film according to claim 9, wherein the light having the first wavelength has a shorter wavelength than the light having the second wavelength. Irradiate the substrate with a polycrystalline silicon thin film on the surface,
Taking an optical image of the first first-order diffracted light generated in the first direction from the substrate irradiated with the light;
Capturing an optical image of the second first-order diffracted light generated in the second direction from the substrate irradiated with the light;
Polycrystalline silicon formed on the substrate by processing a signal obtained by taking an optical image of the first first-order diffracted light and a signal obtained by taking an optical image of the second first-order diffracted light A method for inspecting a polycrystalline silicon thin film, comprising: determining a crystal state of a film.   A first wavelength selective filter that transmits an optical image of the first first-order diffracted light generated in the first direction from the substrate irradiated with the first light and blocks light of other wavelengths. The optical image of the second first-order diffracted light generated in the second direction from the substrate irradiated with the light is transmitted through the second wavelength light, and the light of other wavelengths is shielded. 15. The method for inspecting a polycrystalline silicon thin film according to claim 14, wherein the imaging is performed through the second wavelength selection filter.   The light of the first wavelength is shorter than the light of the second wavelength, and the first direction has a smaller inclination angle than the second direction with respect to the normal direction of the substrate. The method for inspecting a polycrystalline silicon thin film according to claim 15.

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