Substrate processing apparatus and substrate processing method

Abstract

A substrate processing apparatus is disclosed. The substrate processing apparatus includes an imaging unit that photographs trajectories of one or more discharge liquids discharged from a plurality of nozzles, and an inspection unit that calculates impact points of the one or more discharge liquids discharged from the plurality of nozzles and determines whether the impact points of the one or more discharge liquids discharged from the plurality of nozzles are normal. The inspection unit includes an image synthesis unit that synthesizes a plurality of images photographed by the imaging unit, a preprocessing unit that pre-processes image data generated by the image synthesis unit, and a calculation unit that calculates whether the impact points of the one or more discharge liquids discharged from the plurality of nozzles are normal by comparing the image data pre-processed by the preprocessing unit.

Description

TECHNICAL FIELD

[0001] Embodiments of the inventive concept described herein relate to a substrate processing apparatus and a substrate processing method. More particularly, embodiments of the inventive concept relate to an apparatus and a method for identifying whether a hit point of an ejected liquid ejected from a plurality of nozzles is normal in a substrate processing apparatus and a substrate processing method for processing a substrate by ejecting a liquid to the substrate from the plurality of nozzles. BACKGROUND

[0002] Generally, a comparison technique such as template matching is often used as a method of checking a position or a state of a moving target. According to the technique, a reference image of a reference target is first acquired by photographing the target as a reference using a vision camera. Thereafter, an image of an object to be checked is acquired by photographing the object to be checked, and the image is compared with the reference image to determine whether the position or the state of the object to be checked is normal.

[0003] Figure 1 A method of checking a hit point in an existing nozzle is illustrated. Referring to Figure 1 In a conventional method for checking a hit point of a nozzle, the hit point is checked by photographing a liquid ejected from the nozzle along a reference trajectory, setting cross lines intersecting the reference trajectory, and comparing them. Then, in most cases, a pattern is formed in an existing wafer. As Figure 1 The liquid ejected as shown in the flow has a shape of a water droplet, and the water flow cannot maintain its linearity. When the hit point of the nozzle is checked by using the conventional method, Figure 1 When the hit point of the nozzle is checked by using the conventional method, the water flow boundary becomes unclear due to light reflected by the wafer pattern, so that it is not easy to check the hit point.

[0004] [Existing Technical Literature]

[0005] [Patent Literature]

[0006] Korean Patent No. 10-1420159 SUMMARY

[0007] Embodiments of the inventive concept provide a method and an apparatus for checking whether a hit point of a nozzle is normal regardless of an existing pattern.

[0008] The problems to be solved by the inventive concept are not limited to the above-mentioned problems, and those skilled in the art to which the inventive concept pertains will clearly understand other problems to be solved from the specification and the attached drawings.

[0009] According to one example of the inventive concept, a substrate processing apparatus processes a substrate by ejecting an ejected liquid to the substrate from a plurality of nozzles.

[0010] According to one embodiment, a substrate processing apparatus includes: an imaging unit that photographs a trajectory of one or more discharge liquids discharged from a plurality of nozzles; and an inspection unit that calculates a point of impact of the one or more discharge liquids discharged from the plurality of nozzles and determines whether the point of impact of the one or more discharge liquids discharged from the plurality of nozzles is normal.

[0011] According to one example, the inspection unit can include: an image synthesis unit that synthesizes a plurality of images captured by the imaging unit; a preprocessing unit that pre-processes image data generated by the image synthesis unit; and a calculation unit that calculates whether the point of impact of the one or more discharge liquids discharged from the plurality of nozzles is normal by comparing the image data pre-processed by the preprocessing unit.

[0012] According to one example, the image synthesis unit can synthesize a plurality of images, and can synthesize a maximum luminance value image of the plurality of images.

[0013] According to one example, the preprocessing unit can perform a distance distortion correction on the image data generated by the image synthesis unit.

[0014] According to one example, the preprocessing unit can detect a shape of the substrate from the image data on which the distance distortion correction has been performed, and can calculate a center point of the detected substrate shape.

[0015] According to one example, the preprocessing unit can convert a coordinate system into a polar coordinate system with respect to the center point.

[0016] According to one example, the calculation unit can determine whether a nozzle is normal by comparing whether the point of impact of the one or more discharge liquids discharged from the plurality of nozzles corresponds to a threshold range of the nozzle by using a data value obtained in the polar coordinate system.

[0017] According to one example, the imaging unit can be disposed at a position that photographs the substrate obliquely.

[0018] According to one embodiment, a substrate processing method for processing a substrate by using the substrate processing apparatus is disclosed.

[0019] The method can include: continuously photographing droplets discharged from a first nozzle and a second nozzle by operating the imaging unit; pre-processing continuously captured images; and determining whether a point of impact of discharge liquids discharged from the first nozzle and the second nozzle is normal by determining that data of the pre-processed images corresponds to a threshold range depending on flow rates of the first nozzle and the second nozzle.

[0020] According to an example, the continuously capturing the droplets discharged from the first nozzle and the second nozzle by operating the imaging unit can include synthesizing the continuously captured images; and synthesizing the image obtained by the synthesizing into a maximum luminance value.

[0021] According to an example, the pre-processing the continuously captured images can include performing a distance distortion correction on data corresponding to the synthesized image.

[0022] According to an example, wherein the pre-processing the continuously captured images can include detecting a shape of the substrate from the data on which the distance distortion correction has been performed; and detecting a center point of the substrate shape.

[0023] According to an example, the pre-processing the continuously captured images can include converting a coordinate system into a polar coordinate system with respect to the detected center point.

[0024] According to an example, the determining whether the impact point of the discharged liquid from the first nozzle and the second nozzle is normal by determining that the data of the pre-processed image corresponds to the threshold value depending on the flow rate of the first nozzle and the second nozzle can include determining whether the impact point of the discharged liquid from the first nozzle and the second nozzle is normal by comparing a data value in the obtained polar coordinate system with the threshold value depending on the flow rate of the first nozzle and the second nozzle. BRIEF DESCRIPTION OF DRAWINGS

[0025] The above and other objects and features will become apparent from the following description of the embodiments, when taken in conjunction with the accompanying drawings, in which like reference characters indicate like portions of the embodiments and in which:

[0026] Figure 1 FIG. illustrates a method of checking an impact point in an existing nozzle;

[0027] Figure 2 FIG. illustrates a substrate processing apparatus according to an embodiment of the inventive concept;

[0028] Figure 3 is a block diagram illustrating a configuration of a checking unit according to an embodiment of the inventive concept;

[0029] Figure 4 FIG. illustrates a flowchart of a substrate processing method according to an embodiment of the inventive concept; and

[0030] Figures 5 to 9 FIG. illustrates each operation of checking an impact point of a discharged liquid discharged from a plurality of nozzles. DETAILED DESCRIPTION

[0031] The above and other advantages and features of the inventive concept will become apparent from the following description of the following embodiments given in conjunction with the accompanying drawings, which are presented as exemplary explanations of the inventive concept and are not intended to limit the inventive concept thereto. However, the inventive concept is not limited to the embodiments disclosed herein, but can be implemented in various forms, and the embodiments are presented only to make the disclosure of the inventive concept complete and to fully convey the scope of the inventive concept to those skilled in the art to which the inventive concept pertains, and the inventive concept will be defined by the scope of the claims.

[0032] Although not defined, all terms (including technical or scientific terms) used herein can have the same meaning as commonly accepted by those skilled in the art to which the inventive concept belongs. Terms defined in a general dictionary can be interpreted to have the same meaning as those intended in the relevant art and / or the application disclosure, and even if not explicitly defined herein, neither become conceptual nor be interpreted as overly formal.

[0033] Terms such as first and second can be used to describe various elements, but the elements are not limited to these terms. These terms can be used only for the purpose of distinguishing one element from another element. For example, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element, without departing from the scope of the inventive concept.

[0034] Unless otherwise specified, a singular form of a term can include a plural form. Also, in the drawings, the shape and size of elements can be exaggerated for a clearer description.

[0035] The terms used herein are provided to describe the embodiments, not to limit the inventive concept. In the specification, the singular form includes the plural form unless specifically mentioned. The expressions "include" and / or its various corresponding forms, such as "including", used in the specification, do not exclude the presence or addition of one or more components, substances, elements, steps, operations, and / or devices. In the specification, the term "and / or" represents an enumerated configuration or various combinations thereof.

[0036] The term "unit" used throughout the specification is a unit for processing at least one function or operation, and for example, can refer to a hardware element such as an FPGA or an ASIC. However, the "unit" is not limited to software or hardware. The "unit" can be constituted in a storage medium in which addressing can be performed, and can be configured to reproduce one or more processors.

[0037] Accordingly, as an example, a "unit" can include elements, such as software elements, object-oriented software elements, class elements and task elements, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and parameters. The elements and "units" provided the functionality can be individually implemented as hardware, software, and / or other "units" and can be integrated in one or more as hardware, software, and / or other "units."

[0038] Figure 2 A substrate processing apparatus 1 according to an embodiment of the present inventive concept is illustrated.

[0039] Figure 2 The substrate processing apparatus 1 can process a substrate by discharging a discharge liquid to the substrate "W" from a plurality of nozzle discharge holes 11, 12, 13, and 14. According to one example, the discharge liquid can be a cleaning liquid or a chemical.

[0040] According to the substrate processing apparatus 1 of the present inventive concept, a fixed nozzle 10 that discharges a processing liquid to a substrate "W" can be provided. The fixed nozzle 10 can include a plurality of nozzle discharge holes 11, 12, 13, and 14. According to Figure 2 According to one example, an example in which the fixed nozzle includes four nozzle discharge holes 11, 12, 13, and 14 is disclosed. Although one fixed nozzle 10 is disclosed, and in Figure 2 Although an example in which the fixed nozzle 10 includes a plurality of nozzle discharge holes 11, 12, 13, and 14 is disclosed in the embodiment, this is only one embodiment, and two fixed nozzles can be disclosed and each fixed nozzle can include one nozzle discharge hole.

[0041] Hereinafter, a substrate processing apparatus 1 in which one fixed nozzle 10 includes a plurality of nozzle discharge holes 11, 12, 13, and 14 will be described as an example. According to one example, a processing liquid can be discharged from the plurality of nozzle discharge holes 11, 12, 13, and 14. Only some of the plurality of nozzle discharge holes 11, 12, 13, and 14 can discharge the processing liquid. The processing liquid can be provided to a surface of a substrate "W".

[0042] According to one example, the substrate processing apparatus 1 of the present inventive concept can check whether a cleaning liquid or a chemical is normally discharged toward a target point on a substrate "W". Hereinafter, the cleaning liquid and the like will be referred to as a "discharge liquid". The discharge liquid can be discharged toward the target point from a fixed nozzle 10 mounted on a side surface of the substrate "W" while drawing a parabola.

[0043] Figure 2 The substrate processing apparatus 1 can include a bowl-shaped portion 40 disposed to surround the substrate "W".

[0044] According to one example, the ejected liquid ejected from the plurality of nozzle ejection holes 11, 12, 13, and 14 included in the fixed nozzle 10 must be landed at a specific position according to a specific trajectory. However, due to various factors, the impact point on the substrate can become different as the trajectory of the ejected liquid becomes different. To determine this, the substrate processing apparatus 1 can include an imaging unit 20 and an inspection unit 30.

[0045] The imaging unit 20 can photograph the ejected liquid ejected from the fixed nozzle 10. According to one example, the imaging unit 20 can be a vision camera. The imaging unit 20 can photograph at a position at which the substrate "W" can be seen as a whole. The imaging unit 20 can be located at a corner of the chamber at which the substrate "W" can be seen as a whole. According to one example, the imaging unit 20 can photograph the substrate "W" and the ejected liquid ejected to the substrate "W" in real time. The imaging unit 20 can photograph the trajectory of one or more kinds of ejected liquid ejected from the plurality of nozzle ejection holes included in the fixed nozzle 10.

[0046] The inspection unit 30 can be connected to the imaging unit 20 to inspect whether the impact point of the ejected liquid ejected from the fixed nozzle 10 is normal by using the image captured by the imaging unit 20. Hereinafter, the inspection unit 30 will be described in detail with reference to Figure 3 The inspection unit 30 will be described in detail.

[0047] In an embodiment of the Figure 2 , it is shown that the imaging unit 20 and the inspection unit 30 have a separate configuration, but according to another example, these configurations can be embedded in one chamber.

[0048] Figure 3 is a block diagram showing a configuration of the inspection unit 30 according to an embodiment of the present inventive concept.

[0049] The inspection unit 30 can calculate the impact point of one or more kinds of ejected liquid ejected from the plurality of nozzle ejection holes and determine whether the impact point of one or more kinds of ejected liquid ejected from the plurality of nozzle ejection holes is normal. The inspection unit 30 according to the present inventive concept can include an image synthesis unit 31, a preprocessing unit 32, and a calculation unit 33.

[0050] The image synthesis unit 31 according to the present inventive concept can synthesize a plurality of images captured by the imaging unit 20. The image synthesis unit 31 can image the substrate and the trajectory of the ejected liquid ejected from the plurality of nozzles by synthesizing a maximum luminance value image of a plurality of images. According to one example, the image synthesis unit 31 can synthesize a plurality of images captured continuously. According to one example, the image synthesis unit 31 can synthesize six or more images captured continuously.

[0051] The pre-processing unit 32 according to the present inventive concept can pre-process the image data generated by the image synthesizing unit 31. The pre-processing can be a data correction operation performed so that comparison can be made more easily in a process of identifying whether the impact point of the discharged liquid discharged from the nozzle discharge hole is normal by using the image synthesized by the image synthesizing unit 31.

[0052] The pre-processing unit 32 according to the present inventive concept can perform distance distortion correction on the image data generated by the image synthesizing unit 31. The shape of the substrate tiltedly captured can be corrected in a circular form through the distance distortion correction. The pre-processing unit 32 can detect the shape of the substrate from the data on which the distance distortion correction has been performed, and can calculate a center point of the detected substrate shape. Further, the pre-processing unit 32 can perform pre-processing by converting a coordinate system into a polar coordinate system with respect to the center point of the substrate shape.

[0053] By performing the comparison of the impact points and the pre-processing operation for calculation by the pre-processing unit 32, comparison can be easily made.

[0054] The calculation unit 33 according to the present inventive concept can calculate whether the impact points of the discharged liquid discharged from the plurality of nozzles are normal by comparing the data processed by the pre-processing unit 32. According to one example, the calculation unit 33 can determine whether the nozzles are normal by comparing whether the impact points of one or more kinds of the discharged liquid discharged from the plurality of nozzles correspond to a threshold range of the nozzles using the data values obtained in the polar coordinate system. The threshold range of the nozzles can be a range of values determined considering the flow rate value in the nozzles and the position of the trajectory according to the flow rate value. In this way, it can be determined whether the nozzles are normal by identifying and judging whether the angle at which the impact points of the discharged liquid discharged from the nozzles are accurate.

[0055] Figure 4 FIG. 1 illustrates a flowchart of a substrate processing method according to an embodiment of the present inventive concept.

[0056] Reference Figure 4 In the substrate processing method according to the embodiment of the present inventive concept, a plurality of nozzle discharge holes included in the fixed nozzle 10 discharge the processed liquid being photographed. The imaging unit 20 that performs photographing can photograph the substrate and the trajectory of the discharged liquid as one whole, and can continuously photograph the same.

[0057] The maximum brightness image can be synthesized by using the captured continuous images, and a preliminary preprocessing can be performed by performing distance distortion correction on the image having the maximum brightness value. After detecting the shape of the substrate from the image that has undergone the distance distortion correction, the center point of the substrate shape can be calculated, and a second preprocessing can be performed by converting the coordinate system to a polar coordinate system with respect to the center point. Thereafter, the image that has completed the preprocessing can be binarized, and the impact point of the discharge liquid discharged from the nozzle can be derived by the angle value. After setting a specific threshold value in accordance with the flow rate of the discharge liquid discharged from the nozzle, the derived angle value is compared with the threshold value, and when the comparison result is within a certain range, it is determined that the impact point of the discharge liquid discharged from the nozzle is normal, and when the comparison result is outside the certain range, it is determined that the impact point of the discharge liquid discharged from the nozzle is abnormal, and an alarm can be generated. Thereby, the nozzle corresponding to the abnormal impact point can be identified, and the following measures can be taken.

[0058] Figures 5 to 9 The respective operations of checking the impact point of the discharge liquid discharged from the plurality of nozzles are illustrated.

[0059] Figure 5 Images obtained by continuously capturing a plurality of images by the imaging unit 20 according to one example are illustrated. Referring to Figure 5 , an example using six images is shown.

[0060] Figure 6 Synthesized images obtained by synthesizing the continuously captured images according to the embodiment of Figure 5 are illustrated. By synthesizing the continuously captured images, the image synthesis unit 31 can more accurately detect the discharge lines of the plurality of nozzles. Further, the image synthesis unit 31 can synthesize the images to obtain the maximum brightness value, so that the discharge lines can be more clearly seen. According to one example, the image having the maximum brightness value can be synthesized by the following equation.

[0061] I M (i, j) = Max(I N-5 (i, j), I N-4 (i, j),..., I N (i, j)

[0062] Figure 7 is a result obtained by performing distance distortion correction on the synthesized image obtained by synthesizing the continuously captured images according to the embodiment of Figure 6 is illustrated.

[0063] Since the imaging unit 20 is obliquely disposed, it is not possible to set a distance from the imaging unit 20 to the substrate to be the same as the distance from the imaging unit 20 to the reference point. Therefore, the distance distortion correction is performed on the synthesized image obtained by synthesizing the continuously captured images according to the embodiment of Figure 6The synthetic image obtained by successively capturing images of the embodiments of the present application is such that the shape of the wafer is not circular but elliptical, so that it can be difficult to determine the specific impact point. Therefore, correction can be made for the circular shape to correct the distortion that occurs accordingly.

[0064] Reference Figure 8 Since the substrate is corrected to be circular when distance distortion correction is performed, the center point of the substrate can be calculated after the substrate is detected, so that the impact point is detected. Further, after the center point is calculated, the coordinate system can be converted to a polar coordinate system. According to one example, in a regular case, the coordinate system is an (x, y) coordinate system, but this can be converted to an (r, θ) coordinate system, i.e., a rectangular coordinate system. This conversion can be made by the following equation.

[0065]

[0066]

[0067] Reference Figure 9 According to one example, the (x, y) coordinate system of the final impact point of the discharged liquid discharged from the nozzle can be converted to the (r, θ) coordinate system as a polar coordinate system. Thereby, the angle information as information related to the impact point of the discharged liquid discharged from the nozzle can be derived.

[0068] Whether the impact point is normal can be determined by comparing the derived angle information of the nozzle with the impact point information depending on the flow information of the nozzle.

[0069] According to one example, the impact point information depending on the flow information of the nozzle can be as follows.

[0070]

[0071] That is, according to the table, the angle of the impact point can be changed according to the flow rate of the nozzle. The computing unit 33 according to the present inventive concept can determine whether the nozzle is normal by comparing the angle of the impact point of the discharged liquid discharged from the nozzle, which is derived from the actually captured image, with the angle of the impact point set according to the flow rate of the discharged liquid discharged from the nozzle. According to one example, the computing unit 33 can determine whether the angle of the impact point of the discharged liquid discharged from the nozzle, which is derived from the actually captured image, is the same as the angle of the impact point set according to the flow rate of the discharged liquid discharged from the nozzle, and can determine that the impact point is normal when they are the same, and can determine that the impact point is abnormal when they are not the same. According to another example, the computing unit 33 can determine whether the angle of the impact point of the discharged liquid discharged from the nozzle, which is derived from the actually captured image, corresponds to the angle of the impact point set according to the flow rate of the discharged liquid discharged from the nozzle, and can determine that the impact point is normal when they are within an error range, and can determine that the impact point is abnormal when they are outside the error range. The threshold range set according to the present inventive concept can be set by the user in advance. According to one example, the threshold range can correspond to a case in which the angle of the impact point of the discharged liquid discharged from the nozzle, which is derived from the actually captured image, is the same as the angle of the impact point set according to the flow rate of the discharged liquid discharged from the nozzle, or within an error rate of 1% or less.

[0072] According to the present inventive concept, the impact point of the nozzle can be checked regardless of the pattern of the substrate.

[0073] According to the present inventive concept, by checking the impact point of the discharged liquid discharged from the plurality of discharge holes of the fixed nozzle, process accidents due to flow rate variation and nozzle distortion can be prevented in advance.

[0074] Effects of the present inventive concept are not limited to the above-mentioned effects, and those skilled in the art to which the present inventive concept pertains can clearly understand unmentioned effects from the specification and the attached drawings.

[0075] Note that the above-described embodiments are presented for understanding the present inventive concept, and do not limit the scope of the present inventive concept, and various modifiable embodiments also fall within the scope of the present inventive concept. The attached drawings provided according to the present inventive concept only show the best embodiments of the present inventive concept. It should be understood that the technical protection scope of the present inventive concept must be determined by the technical spirit of the claims, and the technical protection scope of the present inventive concept is not limited to the lexical meaning of the claims, but even reaches equivalent inventions.

Claims

1. A substrate processing apparatus for processing a substrate by discharging one or more discharge liquids from a plurality of nozzles to the substrate, the substrate processing apparatus comprising: an imaging unit configured to take an image of a trajectory of the one or more discharge liquids discharged from the plurality of nozzles; and an inspection unit configured to: convert a coordinate system into a polar coordinate system; calculate impact points of the one or more discharge liquids discharged from the plurality of nozzles, and determine whether the impact points of the one or more discharge liquids discharged from the plurality of nozzles are normal by comparing whether the impact points of the one or more discharge liquids discharged from the plurality of nozzles correspond to a threshold range of the nozzles based on a flow rate value in the nozzles and a position of the trajectory according to the flow rate value, using data values obtained in the converted polar coordinate system, wherein, in the comparison, the inspection unit compares an angle of the impact points derived from the actually captured image with an angle of the impact points set according to the flow rate value in the nozzles.

2. The substrate processing apparatus according to claim 1, wherein the inspection unit comprises: an image synthesis unit configured to synthesize a plurality of images taken by the imaging unit; a preprocessing unit configured to pre-process image data generated by the image synthesis unit; and a calculation unit configured to calculate whether the impact points of the one or more discharge liquids discharged from the plurality of nozzles are normal by comparing the image data pre-processed by the preprocessing unit.

3. The substrate processing apparatus according to claim 2, wherein the image synthesis unit synthesizes the plurality of images and synthesizes a maximum luminance value image of the plurality of images.

4. The substrate processing apparatus according to claim 3, wherein the preprocessing unit performs distance distortion correction on the image data generated by the image synthesis unit.

5. The substrate processing apparatus according to claim 4, wherein the preprocessing unit detects a shape of the substrate from the image data on which the distance distortion correction has been performed, and calculates a center point of the detected substrate shape.

6. The substrate processing apparatus according to claim 5, wherein the preprocessing unit converts a coordinate system into the polar coordinate system with respect to the center point.

7. The substrate processing apparatus according to any one of claims 1 to 6, wherein the imaging unit is provided at a position obliquely taking an image of the substrate.

8. A substrate processing method for processing a substrate by using the substrate processing apparatus according to claim 1, the substrate processing method comprising: continuously taking images of liquid droplets discharged from a first nozzle and a second nozzle by operating the imaging unit; pre-processing the continuously captured images; converting a coordinate system into a polar coordinate system; and determining whether the impact point of the discharged liquid discharged from the first nozzle and the second nozzle is normal by determining that the data of the preprocessed image corresponds to a threshold range depending on the flow rate of the first nozzle and the second nozzle, wherein the determining whether the impact point of the discharged liquid discharged from the first nozzle and the second nozzle is normal by determining that the data of the preprocessed image corresponds to the threshold range depending on the flow rate of the first nozzle and the second nozzle includes: determining whether the impact point of the discharged liquid discharged from the first nozzle and the second nozzle is normal by comparing the data value obtained in the converted polar coordinate system with the threshold depending on the flow rate of the first nozzle and the second nozzle, wherein in the comparison, the angle of the impact point derived from the actually captured image is compared with the angle of the impact point set in accordance with the flow rate in the first nozzle and the second nozzle.

9. The substrate processing method according to claim 8, wherein the continuously capturing the liquid droplets discharged from the first nozzle and the second nozzle by operating the imaging unit includes: synthesizing the continuously captured images; and synthesizing the image obtained by the synthesizing into a maximum luminance value.

10. The substrate processing method according to claim 9, wherein the preprocessing the continuously captured images includes: performing distance distortion correction on data corresponding to the synthesized image.

11. The substrate processing method according to claim 10, wherein the preprocessing the continuously captured images includes: detecting the shape of the substrate from the data on which the distance distortion correction has been performed; and detecting a center point of the shape of the substrate.

12. The substrate processing method according to claim 11, wherein the preprocessing the continuously captured images includes: converting a coordinate system into the polar coordinate system with respect to the detected center point.

Images