KR20120035860A - Testing method and apparatus of polycrystalline silicon thin film - Google Patents

Abstract

PURPOSE: An inspecting method of a polycrystalline silicon thin film and an inspecting apparatus thereof are provided to highly maintain a quality of the glass substrate for an organic EL glass substrate or liquid crystal display because crystalline state of an polycrystalline silicon thin film formed through annealing by an excimer laser is inspected at a relatively high precision. CONSTITUTION: An inspecting method of a polycrystalline silicon thin film and an inspecting apparatus comprises a light irradiating unit, a first photographing unit, a second photographing unit, and an image processing unit. The light irradiating unit irradiates light on a substrate(100) where a polycrystalline silicon thin film(120) is formed on a surface. The first photographing unit takes a photograph of an image of scattered light from the polycrystalline silicon thin film around reflected light from the polycrystalline silicon thin film. The second photographing unit takes a photograph of an image of a first diffracted light(152) generated from the polycrystalline silicon thin film where the light is irradiated by the light irradiating unit. The image processing unit processes the image of the scattered light taken by the first photographing unit and the image of the first diffracted light taken by the second photographing unit, thereby inspecting the crystalline state of the polycrystalline silicon thin film.

Description

Inspection method and apparatus therefor for polycrystalline silicon thin film {TESTING METHOD AND APPARATUS OF POLYCRYSTALLINE SILICON THIN FILM}

The present invention relates to a method and an apparatus for inspecting a crystal state of a polycrystalline silicon thin film in which amorphous silicon formed on a substrate is polycrystallized by laser annealing.

Thin Film Transistors (TFTs) used in liquid crystal display devices, organic EL (Electro Luminescence) devices, and the like are subjected to low temperature annealing of a portion of the amorphous silicon formed on the substrate with an excimer laser in order to ensure high speed operation. It is formed in the crystallized region.

As described above, in the case where a part of the amorphous silicon is subjected to low temperature annealing with an excimer laser to polycrystallize, it is required to uniformly polycrystallize, but in practice, the crystallinity may be changed by the influence of the laser light source.

Therefore, as a method of monitoring the occurrence state of the variation of the silicon crystal, Japanese Laid-Open Patent Publication No. 2002-305146 (Patent Document 1) applies a laser beam to a semiconductor film to perform laser annealing and a laser irradiation area. It is described that irradiating the inspection light, detecting the reflected light from the substrate by the irradiated inspection light, and confirming the state of crystallization of the semiconductor film from the intensity change of the reflected light.

Further, Japanese Patent Laid-Open No. 10-144621 (Patent Document 2) discloses inspection light on amorphous silicon before irradiation with a laser to detect the reflected light or transmitted light, and irradiates the inspection light even when the laser is irradiated on the amorphous silicon. The reflected light or transmitted light is detected, and the elapsed time from the time when the difference between the intensity of the reflected light or the transmitted light before the laser irradiation and the laser light is maximized to return to the intensity of the reflected light or the transmitted light before the laser irradiation is detected and the state of laser annealing is detected. Monitoring is described.

Furthermore, Japanese Patent Laid-Open No. 2006-19408 (Patent Document 3) discloses visible light irradiated from a direction of 10-85 degrees with respect to a substrate surface in a region where amorphous silicon formed on a substrate is changed to polycrystalline silicon by excimer laser annealing. Then, it is described that the reflected light is detected by a camera grounded at the same angle range as the irradiation, and the arrangement state of the projections on the crystal surface is examined from the change of the reflected light.

Further, Japanese Patent Laid-Open No. 2001-308009 (Patent Document 4) discloses inspection light on a polycrystalline silicon thin film formed by irradiating an amorphous silicon film with an excimer laser, and diffracted light from the polycrystalline silicon thin film is directed to a diffracted light detector. And the state of the polycrystalline silicon thin film is determined by using the intensity of the diffracted light generated from the region of the regular fine uneven structure having high crystallinity of the polycrystalline silicon thin film as compared with the intensity of the diffraction and scattered light from the region having low crystallinity. Testing is described.

It is known that the surface of the polycrystalline silicon thin film (polysilicon film) formed by irradiating and annealing an excimer laser to a thin film of amorphous silicon is generated in a cycle having fine irregularities. The fine protrusions reflect the degree of crystallinity of the polycrystalline silicon thin film, and are periodically formed on the surface of the polycrystalline silicon thin film having a uniform crystal state (the polycrystalline grain diameter coincides) with regularity with fine irregularities. It is known that fine irregularities are irregularly formed on the surface of a polycrystalline silicon thin film having low uniformity in crystal state (does not coincide in polycrystalline grain size).

Thus, as a method of inspecting the surface state of the polycrystalline silicon thin film whose crystal state is reflected in the reflected light, Patent Document 1 describes that the state of crystallization of the semiconductor film is confirmed from the change in the intensity of the reflected light of the light irradiated to the laser annealed region. The state of crystallization is monitored by an in-process, and since the detection light is a laser for annealing, it is not necessarily detectable by scattered light in which the crystal state is reflected, but scattered light in which the crystal state is reflected. Detection is not described.

Further, Patent Document 2 compares the reflected light from the laser irradiation region during laser annealing with the reflected light before annealing to monitor the progress of the annealing, and similarly to Patent Document 1 for monitoring the state of crystallization by a phosphorus process, It is not described that the detection light is a laser for annealing and detects the scattered light in which the crystal state is reflected.

On the other hand, Patent Document 3 describes that the quality of the crystals of the polycrystalline silicon is examined by changing the light reflected by the arrangement of the projections on the surface of the polycrystalline silicon thin film formed by laser annealing. It is not considered about the amount of reflected light (diffraction light) and its distribution changing with growth.

Further, although Patent Document 4 describes detecting diffracted light generated by projections on the surface of the polycrystalline silicon thin film formed by laser annealing, polycrystalline silicon is monitored by monitoring the intensity level of the diffracted light detected by the diffracted light detector. The state of the film is examined, and it is not described to detect the image of the surface of the polycrystalline silicon thin film and to observe the state of the projection of the region where the surface of the polycrystalline silicon thin film exists.

MEANS TO SOLVE THE PROBLEM This invention solves the subject of the said prior art, makes it possible to observe the surface state of a polycrystalline silicon thin film from the image obtained by imaging the optical image of the surface of a polycrystalline silicon thin film, and to examine the crystal state of a polycrystalline silicon thin film. It is to provide a method and an apparatus for inspecting a polycrystalline silicon thin film.

MEANS TO SOLVE THE PROBLEM In order to solve said subject of the said prior art, in this invention, the inspection apparatus of a polycrystalline silicon thin film irradiates a board | substrate with light irradiation means which irradiates light to the board | substrate with which the polycrystalline silicon thin film was formed in the surface, and this light irradiation means. From the first imaging means for imaging the image of the scattered light from the polycrystalline silicon thin film in the vicinity of the light transmitted through the polycrystalline silicon thin film of the light or reflected by the polycrystalline silicon thin film, and from the polycrystalline silicon thin film irradiated with light by the light irradiation means The crystallization state of the polycrystalline silicon thin film is processed by processing the second imaging means for imaging the generated primary diffracted light, the image of the scattered light obtained by imaging with the first imaging means, and the image of the first diffracted light obtained by imaging with the second imaging means. It comprised with the image processing means to examine.

In addition, in order to solve the above-mentioned problems of the prior art, in the present invention, as a method for inspecting a polycrystalline silicon thin film, light is irradiated to a substrate on which a polycrystalline silicon thin film is formed, and the polycrystalline silicon thin film is irradiated to the substrate. Image of the scattered light from the polycrystalline silicon thin film in the vicinity of the transmitted light or the light specularly reflected by the polycrystalline silicon thin film, the image of the first diffracted light generated from the polycrystalline silicon thin film by the light irradiated to the substrate, and the image of the scattered light An image obtained by picking up an image and an image obtained by picking up an image of first order diffracted light is processed to examine a crystal state of the polycrystalline silicon thin film.

According to the present invention, the crystal state of a polycrystalline silicon thin film annealed with an excimer laser can be inspected with a relatively high accuracy, and the quality of the organic EL glass substrate and the liquid crystal display glass substrate can be maintained high.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the principle of this invention, Comprising: It is sectional drawing of the board | substrate which shows the relationship between the primary diffraction light and the board | substrate transmitted light which generate | occur | produce when light is irradiated from the back surface to the board | substrate with a polycrystal silicon film.
2A is a graph showing a qualitative relationship between laser power and crystal grain size of polycrystalline silicon when an amorphous silicon film is annealed with a laser;
Fig. 2B is a graph showing the relationship between the diffraction angle of the first-order diffracted light generated from the substrate and the crystal grain size of the polycrystalline silicon film when light having a wavelength of 0.4 mu m is irradiated to the substrate on which the polycrystalline silicon film is formed.
Fig. 3 shows the first diffraction light from the substrate when the laser power is annealed by varying the laser powers for each of the substrates (1) to (5) at the angle of θ2 relative to the substrate using a one-dimensional sensor array. A graph plotting the output of each pixel of a one-dimensional sensor array.
FIG. 4 is a graph plotting the average value of the P values of the graphs of FIGS. 3 (1) to (5), the output value of the one-dimensional sensor array in the vicinity thereof, and the laser power during annealing.
FIG. 5 shows light emitted from the back surface of the substrate with respect to each of the substrates of FIGS. 1 to 5 annealed by changing the laser power, and the scattered light in the vicinity of the light transmitted through the substrate is a one-dimensional sensor array. A graph plotting the output value of each pixel of the one-dimensional sensor array when detected using.
FIG. 6 is a graph in which the average value of the point P and the output of the pixel in the vicinity of the graph of FIG. 4 and the output of each pixel which detected the image of the scattered light of FIG. 5 are added, and the laser power at the time of annealing is plotted on the horizontal axis;
Fig. 7 is a block diagram showing the configuration of the entire inspection apparatus for a polycrystalline silicon thin film according to the embodiment of the present invention.
Fig. 8A is a block diagram showing the outline structure of an inspection unit and inspection data processing / control unit in the first embodiment of the present invention.
Fig. 8B is a block diagram showing a schematic configuration of a modification of the inspection unit and inspection data processing / control unit in the first embodiment of the present invention.
Fig. 9 is a flowchart showing a sequence of imaging in the first embodiment of the present invention.
Fig. 10 is a flowchart showing a sequence of image processing in the first embodiment of the present invention.
Fig. 11A is a block diagram showing the outline of the structure of an inspection unit and inspection data processing / control unit in the second embodiment of the present invention.
Fig. 11B is a block diagram showing a schematic configuration of a modification of the inspection unit and inspection data processing / control unit in the second embodiment of the present invention.

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

In the drawings for explaining the present embodiment, those having the same function are denoted by the same reference numerals, and repeated description thereof is omitted as a rule. EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail based on drawing.

First, the principle of this invention is demonstrated using FIGS.

A thin film 110 of amorphous silicon is formed on the substrate in the organic EL or liquid crystal display glass substrate 100 (hereinafter, referred to as a substrate) shown in FIG. 1. By irradiating and scanning an excimer laser (not shown) in a part of the amorphous silicon thin film 110, the amorphous silicon thin film 110 of the portion to which the excimer laser is irradiated is sequentially heated and melted. After the excimer laser is scanned, the molten amorphous silicon thin film 110 is gradually cooled to polycrystalline silicon and crystals grow in the state of polycrystalline silicon. In the present invention, it is examined whether or not this polycrystalline silicon is formed as a normal film in a state where the crystal grains coincide with a desired size.

In FIG. 1, a part of the amorphous silicon thin film 110 formed on the glass substrate 100 is excimer laser annealed to form a polycrystalline silicon thin film 120 in a state where the crystal grain size is matched. The illumination light 151 is irradiated from 150 from the back surface side of the substrate 100 at the incident angle θ1, and a state in which the primary diffracted light 152 is generated in the θ2 direction on the side of the surface of the substrate 100 is shown.

The particle diameter of the polycrystalline silicon thin film 120 formed by this excimer laser annealing depends on the irradiation energy (the product of the laser's power density and irradiation time) of the excimer laser. If this relationship is shown qualitatively, it will become as FIG. 2A. That is, when the power of the laser irradiated onto the amorphous silicon thin film 110 is increased, the crystallization of the amorphous silicon thin film 110 begins to proceed from a portion exceeding an arbitrary energy level, so that the polycrystalline silicon thin film 120 grows. do. And when the power of the laser to irradiate is raised further, the particle diameter of the polycrystalline silicon thin film 120 will grow larger.

Here, when the particle diameters of the polycrystalline silicon thin film 120 are in the same state, protrusions are formed on the surface of the polycrystalline silicon thin film 120 at a substantially constant pitch P according to the grain size of the crystal (even in a direction perpendicular to the drawing of FIG. 1). Protrusions are formed at a constant pitch). The pitch P of the projections on the surface of the film is changed by the crystal grain diameter of the polycrystalline silicon thin film 120.

Meanwhile, in the configuration shown in FIG. 1, the wavelength emitted from the light source 150 is 1 generated from the substrate 100 on which the incident angle θ1 of the illumination light of λ to the substrate 100 and the polycrystalline silicon thin film 120 are formed. Between the exit angle θ2 of the diffracted light and the pitch P of the projections on the surface of the polycrystalline silicon thin film 120,

The relationship indicated by is established.

Now, when the incident angle θ1 of the illumination light to the substrate 100 is 75 degrees and the wavelength λ of the illumination light is 400 nm, the emission angle θ2 of the primary diffracted light and the pitch P of the projection on the surface of the polycrystalline silicon thin film 120 are shown in FIG. The relationship is as shown in 2b.

That is, if there is a fluctuation (distribution) or fluctuation (change over time) due to the power of the excimer laser when annealing the amorphous silicon thin film 110, the particle diameter of the polycrystalline silicon thin film 120 changes from the relationship shown in FIG. 2A. . As a result, the emission angle θ2 of the first-order diffracted light generated from the substrate 100 irradiated from the direction of θ1 changes from the relationship as shown in FIG. 2B. Therefore, when the angle for detecting the first diffracted light of the optical system for detecting the first diffracted light 152 is fixed, the first diffracted light is detected when the particle diameter of the polycrystalline silicon thin film 120 is changed. It may be out of the field of view of the optical system, which may damage the reliability of the inspection of the polycrystalline silicon thin film 120.

FIG. 3 shows the substrate 100 annealed by varying the power of the excimer laser and irradiated with long illumination light 151 in a direction perpendicular to the surface emitted from the light source 150, as shown in FIG. The example which plotted the output from each element of the one-dimensional sensor array when it detects with the long one-dimensional sensor array in the direction perpendicular | vertical with respect to the surface not shown fixed in the direction is shown.

FIG. 3 (1) shows a long time of illumination light 151 irradiated to the substrate 100 annealed with the excimer laser power to the smallest state and detected by a one-dimensional sensor array. The example which plotted the output from each element of the 1-dimensional sensor array is shown. The output from the one-dimensional sensor array reflecting the state of annealing according to the intensity distribution of the excimer laser is obtained. In the example of FIG. 3 (1), since the power of the excimer laser at the time of annealing was insufficient, the brightness exceeding the level of the threshold value 301 could not be detected by the output from the one-dimensional sensor array.

3 to 5 show each element of the one-dimensional sensor array when the illumination light 151 is irradiated to the substrate 100 annealed by increasing the power of the excimer laser sequentially in the case of (1). Plot the output from. (5) shows a case where the substrate 100 is annealed with a laser power of a limit that does not inflict damage. According to the change of the excimer laser power at the time of annealing, the distribution pattern of the light radiate | emitted in the direction of (theta) 2 from the board | substrate 100 to which illumination light 151 was irradiated is changing.

FIG. 4 corresponds to the point P in FIG. 3 (1) to (5) and its vicinity (the area having the solid lines on both sides of the point P in FIG. 3 (1) to (5)). The relationship between the average value of the output from the one-dimensional sensor array element and the excimer laser power at the time of annealing is shown.

The hatched portion in Fig. 4 is determined to be less than or equal to the threshold value set at the level of the luminance value even when the laser power at the time of annealing is equal to or less than the threshold value that causes damage to the substrate 100, and the laser annealing is determined to be defective. Will be. This is a false detection.

On the other hand, in the configuration of FIG. 1, of the illumination light 151 irradiated to the substrate 100, transmitted light traveling straight through the light traveling in the direction 152 indicated by the dotted line through the substrate 100 (direct light from the light source 150) In the case of detecting the scattered light around the transmitted light by shielding the light, the scattered light around the transmitted light is not affected by the size of the particle size if the particle diameter of the polycrystalline silicon thin film 120 is increased to some extent or more.

FIG. 5 shows the vicinity of the pixel P described in FIG. 3 among the outputs of the one-dimensional sensor array element which detected scattered light in the vicinity of the transmitted light transmitted through the substrate 100 when the illumination light 151 was irradiated to the substrate 100. The relationship between the average value of the output value from the element which detected the scattered light from the corresponding area | region and the excimer laser power at the time of annealing is shown.

From this figure, it can be seen that the scattered light in the vicinity of the transmitted light transmitted through the substrate 100 is larger as the annealing power is lower and becomes smaller as the annealing power is increased.

FIG. 6 shows the result of adding the result of detecting the primary diffracted light shown in FIG. 4 and the result of detecting scattered light in the vicinity of the transmitted light shown in FIG. 5.

In the case of FIG. 4, even if the hatched portion is below the threshold value at which the laser power at the time of annealing does not damage the substrate 100, the laser annealing is poor. 6, it can be seen from FIG. 6 that the OK range at the side where the laser power at the time of annealing is high can be widened. That is, the lower limit value of the laser power at the time of annealing is determined from the detection data of the 1st diffraction light shown in FIG. 4, and the detection data of the 1st diffraction light shown in FIG. 6 and the scattering light of the vicinity of transmitted light are mutually added from the result. By determining the upper limit of the laser power at the time of annealing, the setting range of the laser power at the time of annealing can be widened.

In the example shown in FIG. 6, although the data which detected the 1st diffraction light shown in FIG. 4 and the data which detected the scattered light in the vicinity of the transmitted light shown in FIG. 5 were shown simply, the transmitted light shown in FIG. 5 was shown. The data obtained by detecting the scattered light in the vicinity may be weighted and added to the data detected by the first diffracted light shown in FIG. 4. In this case, from the result of adding the detection data corresponding to FIG. 6, the OK range at the side where the laser power at the time of annealing is higher can be widened and detected.

This invention is made | formed based on the above-mentioned principle, and the specific structure of the test | inspection apparatus for implementing the principle of this invention is demonstrated below.

≪ Example 1 >

The whole structure of the inspection apparatus 700 which examines the crystal state of the polycrystalline silicon thin film formed by laser annealing to a part of amorphous silicon film on the glass substrate for organic electroluminescent glass or the liquid crystal display glass substrate which concerns on this invention is shown in FIG. do.

The inspection apparatus 700 includes a substrate rod portion 710, an inspection portion 720, a substrate unloading portion 730, an inspection portion data processing and control portion 740, and an entire control portion 750.

In the organic EL glass substrate or liquid crystal display glass substrate (hereinafter referred to as a substrate) 100 to be inspected, a thin film of amorphous silicon is formed on the glass substrate, and a part of the region is in the process immediately before the inspection process. The superheated region is annealed by irradiating, scanning, and heating the excimer laser to polysilicon to form a polycrystalline silicon thin film. The inspection apparatus 100 captures the image of the surface of the substrate 100 and checks whether the polycrystalline silicon thin film is normally formed.

The board | substrate 100 of a test object is set to the rod part 710 by the conveying means which is not shown in figure. The board | substrate 100 set in the rod part 710 is conveyed to the test | inspection part 720 by the conveyance means which is not shown in figure controlled by the whole control part 750. FIG. 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 100. The data detected by the inspection unit 721 is processed by the inspection data processing and control unit 740 to evaluate the state of the polycrystalline silicon thin film formed on the surface of the substrate 100.

The inspection board | substrate 100 is conveyed to the unloading part 730 from the inspection part 720 by the conveyance means which is not shown and controlled by the whole control part 750, The inspection apparatus (not shown) by the handling unit (not shown) 700) is taken out. In addition, although FIG. 7 shows the structure in which one test | inspection unit 721 is provided in the test | inspection part 720, it depends on the size of the board | substrate 100 to be tested, and the area and arrangement | positioning of the polycrystalline silicon thin film formed. Alternatively, three or more units may be used.

8A shows the configuration of the inspection unit 721 and the inspection unit data processing and control unit 740 in the inspection unit 720.

The inspection unit 721 is composed of an illumination optical system 800, a scattered light imaging optical system 820, a primary diffraction optical imaging optical system 830, and a substrate stage 850. The inspection unit data processing / control unit 740 The inspection unit data processing and control unit 740 is connected to the entire control unit 750 shown in FIG. 7.

The illumination optical system 800 includes a light source 801, a magnification lens 802, a collimated lens 803, a wavelength filter 804, a polarization filter 805, and a cylindrical lens 806 that emit light having multiple wavelengths. ) Are housed in the barrel 810.

The light source 801 emits light of a wide frequency (for example, 300 nm to 700 nm) from the ultraviolet region to the visible region. For example, a halogen lamp, a xenon lamp, or the like is used.

The magnifying lens 802 enlarges the beam diameter of the light emitted from the light source 801. The collimated lens 803 emits light whose beam diameter is enlarged by the magnifying lens 802 as parallel light.

The wavelength filter 804 is for selecting the wavelength to illuminate in accordance with the state of the polycrystalline silicon 120 formed on the substrate 100 to be inspected, and inspects the light from the multi-wavelength light emitted from the light source 801. It is possible to select a wavelength suitable for.

The polarization filter 805 is for controlling the polarization state of the light illuminating the substrate 100, and can detect an image with high contrast according to the state of the polycrystalline silicon 120 formed on the substrate 100 to be inspected. The polarization state of the illumination light can be changed.

The cylindrical lens 806 emits light emitted from the light source 801, collected by the magnification lens 802, and collimated by the collimating lens 803 in accordance with the size of the inspection area on the substrate 100. In order to efficiently illuminate, the illumination light beam is condensed in one direction, and in a direction perpendicular to it, the cross-sectional shape is formed into a long shape in one direction (direction perpendicular to the drawing) in the state of parallel light. By irradiating the substrate 100 with the light condensed in one direction by the cylindrical lens 806, the amount of illumination light of the inspection region on the substrate 100 is increased, and the scattered image imaging optical system 820 and the first diffraction image imaging are performed. By the optical system 830, an image with higher contrast can be detected.

The scattered light imaging optical system 820 includes a light shielding plate 821, an objective lens 822, and a wavelength filter for shielding transmitted light (direct light from the light source 801) emitted from the light source 801 and transmitted through the substrate 100. 823, a polarizing filter 824, an imaging lens 825, and an image sensor 826, which are housed in a barrel portion 827.

The objective lens 822 is for condensing diffracted light (primary diffracted light) generated from the substrate 100 illuminated by the illumination optical system 800. In order to condense the diffracted light efficiently, a relatively large NA (lens Has a numerical aperture :).

The wavelength filter 823 selectively transmits light having a specific wavelength among the light from the substrate 100 condensed by the objective lens 822, and is adapted to the optical characteristics of the polycrystalline silicon thin film formed on the surface of the substrate 100. Therefore, the wavelength to select can be set. The wavelength filter 823 can cut light of wavelengths other than the illumination wavelength from the board | substrate 100 and the periphery.

The polarization filter 824 adjusts the state of the polarization with respect to the light of the specific wavelength which permeate | transmitted the wavelength selection filter 823.

The imaging lens 825 is for forming an optical image by the first order diffracted light from the surface of the substrate 100, and is formed by the polarization filter 824 in light of a specific wavelength transmitted through the wavelength selective filter 823. The image of the light in which the state of polarization was adjusted is imaged.

The image sensor 826 is formed by first-order diffracted light from a pattern formed in an area long in one direction of the surface of the substrate 100 illuminated by the cylindrical lens 805 formed by the imaging lens 825. By imaging an optical image, the board | substrate 100 is comprised with the one-dimensional CCD (telephone coupling element) image sensor or the two-dimensional CCD image sensor arrange | positioned according to the long area | region in one direction illuminated.

The primary diffraction optical image pickup optical system 830 includes an objective lens 831, a wavelength filter 832, a polarization filter 833, an imaging lens 834, and an image sensor 835, which are provided in the barrel portion 836. It is stored.

The objective lens 831 is for condensing diffraction light (primary diffraction light) generated from the substrate 100 illuminated by the illumination optical system 800, and a relatively large NA (lens Has a numerical aperture :).

The wavelength filter 832 selectively transmits light having a specific wavelength among the light from the substrate 100 collected by the objective lens 831, and is adapted to the optical characteristics of the polycrystalline silicon thin film formed on the surface of the substrate 100. Therefore, the wavelength to select can be set.

The polarization filter 833 adjusts the state of the polarization with respect to light of a specific wavelength transmitted through the wavelength selection filter 832.

The imaging lens 834 is for forming an optical image by first-order diffracted light from the surface of the substrate 100, and is formed by the polarization filter 833 at light having a specific wavelength transmitted through the wavelength selective filter 832. The image of the light in which the state of polarization was adjusted is imaged.

The image sensor 835 detects an optical image by the first order diffracted light from the surface of the substrate 100 formed by the imaging lens 834, and is a one-dimensional sensor or two of a CCD (telephone coupling element). It consists of a dimensional sensor.

The board | substrate stage 850 arrange | positions the board | substrate 100 of inspection control on the upper surface, and is comprised with the structure which can be moved in XY plane by the drive means 851.

The outputs from the image sensor 826 of the scattered light imaging optical system 820 and the image sensor 835 of the primary diffraction light detection optical system 830 are input to the inspection data processing / control unit 740, respectively. The inspection data processing / control unit 740 converts the analog image signal output from the image sensor 826 of the scattered light imaging optical system 820 and the image sensor 1165 of the first diffraction light detection optical system 830 into a digital image signal. A / D converters 841 and 843 for converting, image processing units 842 and 844 for processing respective digital image signals, and defect plates for processing respective digital image signals processed to determine defects from image feature amounts An input / output unit 846 having a government unit 845, a display screen 847 for outputting the determined defect information, and image processing units 842 and 844, a defect determination unit 845, an input / output unit 846, and The control part 848 which controls the light source 800, the image sensors 826 and 835, and the drive part 851 of the board | substrate stage 850 is provided. In addition, the control unit 848 is connected to the overall control unit 750 shown in FIG. 7.

8B shows a configuration in which the illumination optical system 800 is arranged on the side of the surface of the substrate 100 as a modification. When the illumination optical system 800, the first diffraction light detection optical system 830, and the scattered light detection optical system 820 do not mechanically interfere with each other, the illumination optical system 800 is connected to the substrate 100 as shown in FIG. 8B. With respect to the primary diffraction light detection optical system 830 and the scattered light detection optical system 820, the light may be disposed on the same side.

Since the arrangement shown in FIG. 8B differs only in the arrangement of the illumination optical system 800, its detailed description is omitted.

With the configuration as shown in FIG. 8A or 8B, the illumination optical system 800 illuminates the substrate 100 placed on the substrate stage 850 so that the incident angle of the illumination light is θ1 from the rear surface side of the substrate 100. The image of the scattered light around the direct light from the light source 801 transmitted through the illuminated substrate 100 is captured by the imaging optical system 820, and the primary diffracted light generated from the illuminated substrate 100 is imaged. The image by the first diffraction optical image detection optical system 830, and the respective imaging data is processed by the inspection data processing / control unit 740 to be formed on the substrate 100 to inspect the crystal state of the polycrystalline silicon thin film. .

Next, a method of inspecting the state of the polycrystalline silicon thin film annealed with an excimer laser on the substrate 100 by the inspection unit 721 and the inspection data processing / control unit 740 having the configuration shown in FIG. 8A. Explain.

First, before performing inspection, the optical conditions are set using the substrate 100 on which the polycrystalline silicon thin film is formed in advance. Optical conditions to be set include illumination wavelength by the wavelength filter 804 of the illumination optical system 800, polarization conditions by the polarization filter 805, detection wavelength by the wavelength filter 823 of the scattered-light imaging optical system 820, and polarization. Polarization conditions of the detection light by the filter 824, the imaging position of the scattered light image by the imaging lens 825, and the like. These conditions are the primary image obtained by the scattering light image obtained by observing the board | substrate 100 illuminated by the illumination optical system 800 with the scattering image pickup optical system 820, and the primary diffraction light detection optical system 830. The diffraction light image is displayed on the display screen 847 of the input / output unit 846, and is adjusted by obtaining a high contrast scattering structure and a first order diffraction light image.

Next, the flow of the process of inspecting the inspection region of the polycrystalline silicon thin film formed by annealing of the excimer laser on the substrate 100 under the set optical conditions will be described. The inspection processing includes an imaging sequence for imaging a predetermined area or the entire surface of the substrate, and an image processing for detecting a defective portion by processing an image obtained by imaging.

First, the imaging sequence will be described with reference to FIG. 9.

Initially, the control unit 846 controls the driving unit 851 of the substrate stage 850 so that the inspection start position of the inspection region of the polycrystalline silicon thin film enters the field of view of the imaging optical system 820, thereby controlling the substrate 100 to an initial position ( Inspection start position) (S901).

Next, the driving unit 851 is controlled by the control unit 847 to illuminate the polycrystalline silicon thin film by the illumination optical system 800 (S902), and to move the imaging area of the imaging optical system 820 along the inspection area of the illuminated polycrystalline silicon thin film. ) Is controlled to start the movement of the substrate stage 850 at a constant speed (S903).

While first moving the substrate stage 850 at a constant speed, the first diffraction image image is captured by the first diffraction light image generated by the illumination light transmitted through the long inspection region in one direction of the polycrystalline silicon thin film illuminated by the illumination optical system 800. The image is captured by the optical system 830, and the image of reflected light scattered light near the optical axis of the transmitted light (in the configuration in FIG. 8B) is captured by the imaging optical system 820 (S904). An analog signal is output from the image sensor 826 of the scattered light imaging optical system 820 and input to the A / D conversion unit 841 of the inspection data processing / control unit 740. An analog signal is output from the image sensor 835 of the primary diffraction optical image pickup optical system 830 and input to the A / D converter 843 of the inspection data processing / control unit 740. The digital signal converted by the A / D conversion unit 841 is input to the image processing unit 842, and a digital image signal is created using the positional information of the substrate stage 850 obtained through the control unit 848. The digital signal converted by the conversion unit 843 is input to the image processing unit 844 to generate and process the digital image signal using the position information of the substrate stage 850 obtained through the control unit 848 (S905). The above operation is repeatedly executed until the inspection area for one line ends (S906).

Next, it is checked whether there is an inspection area adjacent to the area for one line inspected (S907), and if there is an adjacent inspection area, the substrate stage 850 is moved to an adjacent inspection area (S908). ), And the steps from S904 to S907 are repeated. When all the regions to be inspected have finished inspection, the movement of the substrate stage 850 is stopped (S909), the illumination is turned off (S910), and the imaging sequence is terminated.

Next, the detailed sequence of step S905 of creating and processing the obtained digital image in the imaging sequence of FIG. 9 will be described with reference to FIG. 10.

In the imaging step S904 in FIG. 9, the scattered light image is captured by the scattered light imaging optical system 820, and the analog signal output from the image sensor 826 is converted into an A / D converter 841 of the inspection data processing / control unit 740. (S1001), the A / D converter 841 converts it into a digital signal (S1002), and the converted scattered light digital signal is sent to the image processor 842 to generate a digital image signal (S1003), The generated digital image signal of the scattered light image is subjected to preprocessing such as shading correction, averaging processing (S1004), and the image feature amount is extracted (S1005).

On the other hand, inspection data processing is performed on the analog signal output from the image sensor 835 of the primary diffraction optical image detection optical system 830 which detected the image of the primary diffraction light generated from the substrate 100 illuminated by the illumination optical system 800. Input to the A / D converter 843 of the control unit 740 (S1011), converted to a digital signal by the A / D converter 843 (S1012), the digital signal of the converted first diffracted light image is an image processing unit The digital image signal is sent to 844 to generate a digital image signal (S1013). The digital image signal generated is subjected to preprocessing such as shading correction and averaging (S1014). Image feature amounts such as the like are extracted (S1015). The digital image signal of the scattered light from which the image feature amount is extracted and the digital image signal of the first diffracted light are respectively input to the defect determination unit 845 together with the information of the extracted image feature amount (S1021).

The defect determination unit 845 compares the image feature amount (for example, a signal obtained by adding a luminance value to one line scan for each pixel) of each image with a preset reference data (threshold value) to determine a defect. Is performed (S1022). In this defect determination process, it is possible to determine whether the area determined as a defect smaller than the threshold value is caused by insufficient power of laser annealing or excessive power, based on the principle described with reference to FIGS. 4 to 6. have.

The digital image data including the determined defect is sent to the input / output unit 846, and the image by the scattered light is displayed on the display unit 847 together with the positional information on the substrate 100 (S1023) to end the sequence of image processing. . On the image by the scattered light displayed on this display part 847, it is displayed so that the area | region determined by the defect determination part 845 can be distinguished from the normal area | region. In addition, when the defect determination criterion is changed by inputting from the input / output unit 846, the defect area is also displayed in response to the changed defect determination criterion.

By inspecting with the above-described configuration, according to the first embodiment, the crystal state of the polycrystalline silicon thin film annealed with the excimer laser can be inspected with a relatively high accuracy, and the quality of the organic EL glass substrate or the liquid crystal display glass substrate is increased. It becomes possible to maintain.

In addition, in Example 1, although the structure which provided the wavelength filter and the polarizing filter in each of the illumination optical system 800, the scattered-light imaging optical system 820, and the 1st diffraction optical image detection optical system 830 was demonstrated, these necessarily It is not necessary for all the optical systems, and for example, the wavelength filter and the polarization filter may be provided only in the illumination optical system 800, or the wavelength may be provided in the scattered light imaging optical system 820 and the first diffraction optical detection optical system 830. It is good also as a structure which provides a filter and a polarizing filter. In addition, only one of the wavelength filter and the polarization filter may be used.

In addition, although it demonstrated by the structure which illuminates an elongate area | region in one direction on the board | substrate 100 using the cylindrical lens 805 to the illumination optical system 800, even if it replaces it with a conventional circular lens, the same effect will be acquired. Lose.

<Example 2>

A second embodiment of the present invention will be described with reference to Figs. 11A and 11B.

The configuration in the second embodiment shown in FIG. 11A is the configuration in the first embodiment described in FIG. 8A, and the scattered-light imaging optical system 1120 of the inspection unit 1110 is launched from the illumination optical system 800. The different illumination light differs in that it is inclined with respect to the optical axis of the transmitted light transmitted through the substrate 100.

The scattered light imaging optical system 1120 in Example 2 includes an objective lens 1121, a wavelength selective filter 1122, a polarization filter 1123, an imaging lens 1124, and an image sensor 1125. It is stored in the barrel 1126.

By installing the scattered-light imaging optical system 1120 inclined with respect to the transmitted optical axis, the traveling direction of the transmitted light transmitted through the substrate 100 is shifted from the optical axis of the scattered-light imaging optical system 1120, thereby forming an image on the image sensor 1125. Instead, the image sensor 1125 detects an image of scattered light in the vicinity of the transmitted light.

That is, in the scattered-light-imaging optical system 1120 in the second embodiment, it is not necessary to provide a corresponding one in the light shielding plate 821 of the scattered-light-imaging optical system 820 described in the first embodiment, and only the objective lens 822 is used. ) The light receiving surface can be large. As a result, since the light amount of scattered light detected by the image sensor 1125 can be increased, the sensitivity of the detection can be improved.

In the configuration shown in FIG. 11A, the signals output from the scattered light imaging optical system 1120 and the first diffraction optical imaging optical system 830 are respectively used for the A / D converters 1141 and 1143 of the inspection data processing / control unit 1140. Is converted into a digital signal, is image-processed by the image processing units 1142 and 1144 and sent to the defect determination unit 1145 to determine a defect from the image feature amount, and outputs the defect information determined by the input / output unit 1146. do.

11A is the same as the configuration shown in FIG. 8A described in the first embodiment by including the inspection data processing / control unit 1140 in the configuration other than the scattered light imaging optical system 1120, and a detailed description thereof will be omitted. do.

In addition, although FIG. 11A showed the example which inclined the scattered-light-imaging optical system 1120 with respect to the advancing direction of the transmitted light in the lower side of the figure, in the upper side or horizontal (direction perpendicular | vertical to the surface) of the figure with respect to the advancing direction of the transmitted light. Similar effects can be obtained by tilting.

FIG. 11B corresponds to the configuration described in FIG. 8B of the first embodiment, and differs from the case where the scattered light imaging optical system 1120 is inclined with respect to the traveling direction of the reflected light as in the case of FIG. 11A.

Since the operation of each part in the configuration shown in FIG. 11B is the same as that described in FIG. 8B of the first embodiment, description thereof is omitted. In the case of FIG. 11B, similarly to the case of FIG. 11A, the same effect can be obtained even when the scattered-light imaging optical system 1120 is inclined with respect to the traveling direction of the reflected light in the upper side or the horizontal side (the direction perpendicular to the ground) of the drawing.

According to Examples 1 and 2, a method of evaluating the crystal state of a polycrystalline silicon thin film by illuminating the polycrystalline silicon thin film to image an image of diffracted light generated by irregularities on the surface of the film, and processing the image of the diffracted light obtained by the imaging; The device can be provided.

As mentioned above, although the invention made by this inventor was demonstrated concretely based on the Example, this invention is not limited to the said Example, Of course, it can be variously changed in the range which does not deviate from the summary.

Although the above is description of the invention, the present invention is not limited to the above-described embodiment, and various modifications are included. For example, the above-described embodiments are described in detail in order to clearly describe the present invention, and are not necessarily limited to those having all the configurations described. It is also possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of a certain embodiment. In addition, it is possible to add, delete, or replace other configurations to a part of the configurations of each embodiment.

Claims (12)

Light irradiation means for irradiating light to a substrate having a polycrystalline silicon thin film formed on a surface thereof;
First imaging means for imaging an image of scattered light from the polycrystalline silicon thin film in the vicinity of light transmitted through the polycrystalline silicon thin film or light reflected by the polycrystalline silicon thin film among the light irradiated to the substrate by the light irradiation means;
Second imaging means for imaging an image of primary diffracted light generated from the polycrystalline silicon thin film irradiated with light by the light irradiation means;
Image processing means for inspecting a crystal state of the polycrystalline silicon thin film by processing an image of said scattered light obtained by imaging with said first imaging means and an image of said primary diffracted light obtained by imaging with said second imaging means
An inspection apparatus for a polycrystalline silicon thin film, comprising: The method of claim 1,
The first imaging means has a light shielding plate for shielding light transmitted through the polycrystalline silicon thin film or light reflected from the polycrystalline silicon thin film, and light transmitted through the polycrystalline silicon thin film not shielded from the light blocking plate or the polycrystalline silicon thin film. An image of scattered light from the polycrystalline silicon thin film in the vicinity of the light reflected by the image pickup device. The method of claim 1,
The first imaging means is inclined with respect to the traveling direction of the light transmitted through the polycrystalline silicon thin film or the light reflected from the polycrystalline silicon thin film so that the light transmitted through the polycrystalline silicon thin film or the light reflected from the polycrystalline silicon thin film is not detected. And a device for inspecting a polycrystalline silicon thin film, which is provided. The method of claim 1,
The light irradiation means irradiates the light from the back surface side of the substrate, and the imaging means is irradiated to the back surface side of the substrate by the light irradiation means to image an image of scattered light scattered from the surface side of the polycrystalline silicon thin film. Inspection device for a polycrystalline silicon thin film, characterized in that. The method of claim 1,
The light irradiation means irradiates the light from the surface side of the substrate, and the imaging means is the scattered light scattered from the surface side of the polycrystalline silicon thin film by the light irradiated to the surface side of the substrate by the light irradiation means. An inspection apparatus for a polycrystalline silicon thin film, which images an image. The method of claim 1,
The light irradiation means includes a wavelength selector to irradiate the substrate with the light selected by the wavelength selector to the substrate, and the first imaging means includes a polarizing filter, wherein scattered light in the vicinity of transmitted light or reflected light from the substrate is provided. A device for inspecting a polycrystalline silicon thin film, characterized by imaging an image of primary diffracted light by light transmitted through a polarizing filter. Light is irradiated onto a substrate having a polycrystalline silicon thin film formed on a surface thereof,
An image of scattered light from the polycrystalline silicon thin film in the vicinity of light transmitted through the polycrystalline silicon thin film or light reflected by the polycrystalline silicon thin film among the light irradiated onto the substrate,
Imaging the image of the first-order diffracted light generated from the polycrystalline silicon thin film by the light irradiated to the substrate,
Processing an image obtained by imaging the scattered light image and an image obtained by imaging the first diffracted light to inspect the crystal state of the polycrystalline silicon thin film
Inspection method of a polycrystalline silicon thin film, characterized in that. The method of claim 7, wherein
The imaging of scattered light from the polycrystalline silicon thin film in the vicinity of the light transmitted through the polycrystalline silicon thin film or the light specularly reflected by the polycrystalline silicon thin film includes light transmitted through the polycrystalline silicon thin film or light specularly reflected by the polycrystalline silicon thin film. And imaging the image of scattered light from the polycrystalline silicon thin film in the vicinity of the light transmitted through the polycrystalline silicon thin film not shielded by the shading or reflected from the polycrystalline silicon thin film. Method of inspection. The method of claim 7, wherein
The light transmitted through the polycrystalline silicon thin film or the image of scattered light from the polycrystalline silicon thin film in the vicinity of light transmitted through the polycrystalline silicon thin film or light reflected by the polycrystalline silicon thin film among the light irradiated to the substrate is imaged. A method for inspecting a polycrystalline silicon thin film, characterized in that it is performed by inclining an image with respect to a traveling direction of light transmitted through the polycrystalline silicon thin film or light reflected by the polycrystalline silicon thin film so that light reflected from the polycrystalline silicon thin film is not detected. The method of claim 7, wherein
Irradiating light onto the substrate irradiates light from the back surface side of the substrate, and imaging the scattered light image is irradiated to the back surface side of the substrate to image the scattered light scattered from the surface side of the polycrystalline silicon thin film. It performs by making it, The inspection method of the polycrystalline silicon thin film characterized by the above-mentioned. The method of claim 7, wherein
Irradiating light to the substrate is irradiated with light from the surface side of the substrate, and imaging the image of the scattered light is irradiated to the surface side of the substrate from the scattered light scattered from the surface side of the polycrystalline silicon thin film. A method for inspecting a polycrystalline silicon thin film, which is performed by imaging an image of scattered light in the vicinity of the specularly reflected light. The method of claim 7, wherein
The light irradiated to the substrate is light having a wavelength selected, and the image of scattered light in the vicinity of the transmitted light or reflected light from the substrate to be imaged is an image of scattered light by light transmitted through the polarizing filter. .

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