Nozzle position detection method, nozzle position adjustment method, computer program, and substrate processing apparatus.

Abstract

This technology allows for high-precision detection of the nozzle position using only a single camera. [Solution] The nozzle position detection method includes the steps of: acquiring a first image Ph1 by imaging a nozzle 412 positioned at a first position and a mirror image of the nozzle 412 reflected on the reflective surface Ws of the substrate W; acquiring a second image Ph2 by imaging a nozzle 412 positioned at a second position and a mirror image of the nozzle 412 reflected on the reflective surface Ws of the substrate W; and acquiring a first inter-image distance d1 between the nozzle real image 412a and the nozzle mirror image 412b in the first image Ph1, and a second inter-image distance d2 between the nozzle real image 412a and the nozzle mirror image 412b in the second image Ph2. Furthermore, the nozzle position detection method includes the steps of calculating the substrate nozzle distances x1 and x2 from the substrate W to the nozzle 412 using the amount of movement t when the nozzle 412 is moved from the first position to the second position, the first inter-image distance d1, and the second inter-image distance d2.

Description

Technical Field

[0001] The subject matter disclosed in this specification relates to a nozzle position detection method, a nozzle position adjustment method, a computer program, and a substrate processing apparatus.

Background Art

[0002] In the manufacturing process of semiconductor devices, when performing resist processing on a wafer or development processing after exposure, a plurality of coating processing apparatuses are used. These coating processing apparatuses include, for example, a spin chuck that rotates while holding a wafer, and a nozzle that discharges a coating liquid onto the wafer. When performing a coating process, the nozzle moves to a specified position, and a desired coating step is performed by discharging a processing liquid from the nozzle.

[0003] If the nozzle is displaced from the desired position, there is a possibility of defects such as non-uniform coating of the processing liquid on the wafer or local non-coating. Therefore, it is necessary to accurately adjust the nozzle position with respect to the wafer in advance. However, these adjustments are performed by an operator using an adjustment jig or the like, and the degree of adjustment varies depending on the skill level, and the working hours are greatly increased.

[0004] Patent Document 1 discloses a method for adjusting the nozzle position using a camera. Specifically, two CCD cameras are arranged such that their imaging directions are orthogonal in a plan view, and the left-right displacement is detected by one camera, and the depth displacement is detected by the other camera simultaneously. In both camera images, the nozzle position is adjusted so that the center position of the nozzle tip (the midpoint of the straight line connecting the left and right ends) coincides with the position of the center of the spin chuck.

[0005] Also, as a method using one camera, Patent Document 1 discloses that first, the tip of the nozzle is approximated to about 0.5 mm above the upper surface of the spin chuck, the center position of the nozzle tip and the center position of the suction port are made to coincide in the left-right direction on the camera image, and further, the distance between the front end on the front side of the nozzle tip and the front end on the front side of the suction port is adjusted to a predetermined value. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2012-104732 [Overview of the initiative] [Problems that the invention aims to solve]

[0007] However, conventional technology, which uses two cameras, presented problems such as requiring installation space, increasing costs, and complicating the system. Furthermore, even with position adjustment using a single camera, the system assumes that the relative positions of the camera and nozzle remain constant, so there was a risk of misalignment if the camera position changed.

[0008] The purpose of this disclosure is to provide a technology that can detect the position of a nozzle with high precision, even with just one camera. [Means for solving the problem]

[0009] To solve the above problems, the first embodiment is a nozzle position detection method, comprising: a) holding a substrate having a reflective surface with a substrate holding part; b) acquiring a first image by imaging a nozzle positioned at a first position and a mirror image of the nozzle reflected on the reflective surface of the substrate; c) acquiring a first inter-image distance between the actual image of the nozzle and the mirror image of the nozzle in the first image; d) moving the nozzle from the first position to a second position in the vertical direction of the substrate after step c); e) acquiring a second image by imaging the nozzle at the second position and a mirror image of the nozzle reflected on the reflective surface of the substrate; f) acquiring a second inter-image distance between the actual image of the nozzle and the mirror image of the nozzle in the second image; and g) calculating the substrate-nozzle distance from the substrate to the nozzle using the amount of movement when the nozzle was moved from the first position to the second position in step d), the first inter-image distance, and the second inter-image distance.

[0010] The second embodiment is the nozzle position detection method according to the first embodiment, wherein step g) includes a step of calculating a conversion coefficient that converts the inter-image distance between the real image of the nozzle and the mirror image of the nozzle into the inter-nozzle distance between the substrate nozzles.

[0011] The third aspect is the nozzle position detection method of the second aspect, wherein the first inter-image distance is the number of pixels between the real image of the nozzle and the mirror image of the nozzle in the first image, the second inter-image distance is the number of pixels between the real image of the nozzle and the mirror image of the nozzle in the second image, and the conversion coefficient is the value obtained by dividing the amount of movement of the nozzle by the change in the first inter-image distance and the second inter-image distance.

[0012] The fourth aspect is a nozzle position detection method according to any of the first to third aspects, wherein step c) includes c-1) detecting the positions of the real image and the mirror image of the nozzle in the first image by pattern matching, and c-2) obtaining the first inter-image distance using the detection result of step c-1).

[0013] The fifth aspect is a nozzle position adjustment method, comprising: A) a step of calculating the distance between substrate nozzles using a nozzle position detection method according to any of the first to fourth aspects; B) a step of determining whether the distance between substrate nozzles calculated in step A) has reached a predetermined target distance; and C) if it is determined in step B) that the distance between substrate nozzles has not reached the target distance, a step of moving the nozzles so that the distance between substrate nozzles approaches the target distance.

[0014] The sixth aspect is a nozzle position adjustment method according to the fifth aspect, wherein in step C), the nozzle is moved to approach the target distance based on the number of pixels present between the substrate nozzle distance and the target distance.

[0015] The seventh aspect is a computer program that can be executed by a computer, which causes the computer to execute any of the nozzle position detection methods of the first to fourth aspects.

[0016] The eighth embodiment is a substrate processing apparatus comprising a substrate holding unit for holding a substrate, a nozzle for discharging a processing liquid, a nozzle driving unit for moving the nozzle, an imaging unit, and a control unit for controlling the nozzle driving unit, wherein the control unit executes a nozzle position detection method according to any of the first to fourth embodiments. [Effects of the Invention]

[0017] According to the first to eighth embodiments, the distance between the substrate nozzles can be calculated using the amount of movement when the nozzle is moved and the inter-image distance in the images obtained by taking pictures with a camera before and after the movement. Therefore, the position of the nozzle relative to the substrate can be detected with high accuracy.

[0018] According to the second embodiment, the inter-image distance can be converted to the inter-substrate nozzle distance by calculating a conversion coefficient.

[0019] According to the fourth aspect, since pattern matching is a relatively simple algorithm, it does not require special hardware and can be implemented on a general-purpose CPU, and the processing time can be stabilized. In addition, because the relationship between prior parameter adjustments, such as adjusting the similarity threshold and setting the search range, and the detection results is relatively clear, troubleshooting when problems occur can be easily done. [Brief explanation of the drawing]

[0020] [Figure 1] This is a plan view of a substrate processing apparatus according to an embodiment. [Figure 2] Figure 1 is a longitudinal cross-sectional view of the processing unit. [Figure 3] This is a block diagram showing the electrical connections between the control unit and each part within the processing unit. [Figure 4]It is a diagram showing the flow of nozzle position detection processing and nozzle position adjustment processing executed by the control unit. [Figure 5] It is a diagram schematically showing the first image acquired by the camera. [Figure 6] It is a diagram conceptually showing the detection of the positions of the nozzle real image and the nozzle mirror image. [Figure 7] It is a conceptual diagram for explaining the relationship between the inter-image distance and the substrate-nozzle distance.

Embodiments for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, for ease of understanding, the dimensions and numbers of each part may be exaggerated or simplified.

[0022] <1. Embodiment> FIG. 1 is a plan view of a substrate processing apparatus 100 according to an embodiment. This substrate processing apparatus 100 is an apparatus that supplies a processing liquid to the surface of a disc-shaped substrate W (for example, a silicon wafer) in a semiconductor wafer manufacturing process to process the surface of the substrate W. As shown in FIG. 1, the substrate processing apparatus 100 includes an indexer 101, a plurality of processing units 102, and a main transfer robot 103.

[0023] The indexer 101 is a part that carries in the substrate W before processing from the outside and carries out the substrate W after processing to the outside. A plurality of carriers are arranged on the indexer 101. Each carrier accommodates a plurality of substrates W. A transfer robot (not shown) is arranged on the indexer 101. The transfer robot transfers the substrate W between the carriers in the indexer 101 and the processing unit 102 or the main transfer robot 103.

[0024] The processing unit 102 is a so-called single-wafer processing unit that processes substrates W one at a time. Multiple processing units 102 are arranged around the main transport robot 103. In this embodiment, four processing units 102 arranged around the main transport robot 103 are stacked in three layers in the height direction. That is, the substrate processing apparatus 100 of this embodiment has a total of 12 processing units 102. Multiple substrates W are processed in parallel in each processing unit 102. The number of processing units 102 in the substrate processing apparatus 100 may be one or two or more.

[0025] The main transport robot 103 is a mechanism for transporting substrates W between the indexer 101 and a plurality of processing units 102. The main transport robot 103 has, for example, a hand for holding substrates W and an arm for moving the hand. The main transport robot 103 takes the substrates W before processing from the indexer 101 and transports them to the processing units 102. When processing of the substrates W in the processing units 102 is completed, the main transport robot 103 takes the processed substrates W from the processing units 102 and transports them to the indexer 101.

[0026] <Processing Unit> Next, we will describe the configuration of the processing unit 102. Below, we will describe one of the multiple processing units 102, but since the other processing units 102 have a similar configuration, we will omit detailed explanations.

[0027] Figure 2 is a longitudinal cross-sectional view of the processing unit 102 shown in Figure 1. As shown in Figure 2, the processing unit 102 comprises a chamber 10, a substrate holding unit 20, a rotating mechanism 30, a processing liquid supply unit 40, a processing liquid collection unit 50, a camera 71, an illumination unit 73, and a control unit 80.

[0028] Chamber 10 is a housing that encloses a processing space 11 for processing substrates W. Chamber 10 has side walls 12 surrounding the sides of the processing space 11, a top plate 13 covering the upper part of the processing space 11, and a bottom plate 14 covering the lower part of the processing space 11. A substrate holding unit 20, a rotating mechanism 30, a processing liquid supply unit 40, a processing liquid collection unit 50, a camera 71, and a lighting unit 73 are housed inside Chamber 10. Part of the side wall 12 is provided with an entrance / exit for loading and unloading substrates W into and out of Chamber 10, and a shutter for opening and closing the entrance / exit.

[0029] The substrate holding unit 20 is a mechanism that holds the substrate W in a horizontal position (a position in which the normal to the main surface of the substrate W is aligned with the vertical direction) inside the chamber 10. The substrate holding unit 20 is configured to rotate the substrate W while holding its lower surface by suction. As shown in Figure 2, the substrate holding unit 20 has a disc-shaped spin base 21 and a suction device 23.

[0030] The spin base 21 has a circular upper surface 211 that adsorbs and holds the central portion of the lower surface of the substrate W. The spin base 21 is attached to the upper end of a support shaft 33 that extends vertically from the rotation mechanism 30. Multiple suction holes are formed on the upper surface 211 of the spin base 21. The multiple suction holes are flow-connected to a suction device 23 via an suction path 213. The suction path 213 is provided inside the spin base 21 and the support shaft 33, as shown by the thick dotted line in Figure 2. The suction device 23 includes a suction mechanism such as an aspirator. The suction device 23 sucks the atmosphere from the space above the upper surface 211 of the spin base 21 through the suction path 213 and the multiple suction holes and discharges it outside the substrate processing apparatus 100. Note that holding the substrate W by adsorption is not essential. For example, the substrate can also be held by multiple chuck pins provided on the upper surface of the spin base 21.

[0031] The rotation mechanism 30 is a mechanism for rotating the spin base 21 of the substrate holder 20. The rotation mechanism 30 has a spin motor 32 and a support shaft 33. The support shaft 33 extends vertically, its lower end is connected to the spin motor 32, and its upper end is fixed to the center of the lower surface of the spin base 21. When the spin motor 32 is driven, the support shaft 33 rotates about its axis 330. Along with the support shaft 33, the substrate holder 20 and the substrate W held by the substrate holder 20 also rotate about the axis of the support shaft 33.

[0032] The processing liquid supply unit 40 has an upper nozzle unit 41 and a plurality of lower nozzles 42. As shown in Figures 1 and 2, the upper nozzle unit 41 has a nozzle arm 411, a nozzle 412, and a nozzle drive unit 413. The nozzle 412 is provided at the tip of the nozzle arm 411. The nozzle drive unit 413 moves the nozzle arm 411 in one direction along the horizontal plane and in the vertical direction. When the nozzle arm 411 moves in the horizontal direction, the nozzle 412 moves in one direction along the horizontal plane between a processing position above the substrate W and a retracted position outside the cup 51 in the processing liquid collection unit 50. Also, when the nozzle arm 411 moves in the vertical direction, the nozzle 412 moves along the vertical direction, approaching or moving away from the substrate W. The nozzle drive unit 413 has, for example, a motor or a ball screw mechanism.

[0033] The nozzle 412 is connected to a coating liquid supply system 44 that supplies a coating liquid as a processing liquid. The coating liquid supply system 44 supplies a resist liquid as the coating liquid. When the valve of the processing liquid supply unit is opened with the nozzle 412 positioned at the processing location, the processing liquid supplied from the coating liquid supply system 44 is discharged from the nozzle 412 toward the upper surface of the substrate W held by the substrate holding unit 20. A single processing unit 102 may be provided with multiple nozzles 412.

[0034] Multiple bottom nozzles 42 are arranged between the inner circumferential end of the outer peripheral wall portion 513 of the cup 51 and the spin base 21 in a top view. In a top view, the multiple bottom nozzles 42 are arranged at equal angular intervals with respect to the center of the spin base 21 so as to surround the spin base 21. The upper end of each bottom nozzle 42 is provided with an upward-facing discharge port. The substrate processing apparatus 100 has, for example, four bottom nozzles 42. The discharge ports of the bottom nozzles 42 face the lower surface of the substrate W held by the spin base 21. The bottom nozzles 42 are connected to a rinse liquid supply system 46. When rinse liquid is supplied to the bottom nozzles 42 from the rinse liquid supply system 46, the rinse liquid is discharged from the discharge ports of the bottom nozzles 42 toward the lower surface of the substrate W. The rinse liquid is, for example, a volatile solvent (such as thinner) capable of dissolving resist.

[0035] The processing liquid collection section 50 is the part that collects the processing liquid after use. As shown in Figure 2, the processing liquid collection section 50 has a cup 51. The cup 51 can be moved up and down by a lifting mechanism (not shown). The cup 51 is provided so as to surround the spin base 21 when viewed from above. As shown in Figure 2, the cup 51 has a bottom portion 511 and an outer peripheral wall portion 513. The bottom portion 511 has a substantially annular shape when viewed from above. The inner peripheral end of the bottom portion 511 is bent upward. The outer peripheral wall portion 513 extends upward from the outer peripheral end of the bottom portion 511, then bends inward and extends diagonally upward toward the inner spin base 21.

[0036] A drain 515 is provided at the bottom 511 of the cup 51. A drain guide pipe 55 is attached to the portion of the bottom 511 that forms the drain 515. The lower end of the drain guide pipe 55 is connected to a drainage system (not shown).

[0037] In the coating process of the substrate processing apparatus 100, the first step is a liquid film formation step. In this step, the substrate W is held in a horizontal position by the substrate holding unit 20 and rotation is started in a room temperature environment (e.g., 23°C). Then, the cup 51 is positioned to face the outer edge of the substrate W, and the nozzle 412 of the upper nozzle unit 41 moves above the substrate W to supply room temperature resist liquid (viscosity 1 cP to 20,000 cP) to the upper surface of the substrate W. In the liquid film formation step, the scattered resist liquid is caught by the cup 51 and guided to the drainage system. In the liquid film drying step that follows the liquid film formation step, the rotation of the substrate W continues with the supply of resist liquid stopped, shaking off excess resist liquid and drying the liquid film. This forms a resist film with a predetermined thickness (e.g., 20 nm to 20,000 nm). Following the liquid film drying step, a resist removal step is performed. In the resist removal process, a rinse solution at a temperature above that of the spin base 21 is supplied from the bottom nozzle 42 to remove the resist liquid and resist film adhering to the underside of the substrate W. Unwanted materials are then removed through a drying process by rotation. After these processes, the substrate W is removed from the apparatus and sent to the exposure apparatus.

[0038] Camera 71 is a mechanism for imaging a predetermined area within the chamber 10. The processing unit 102 may have two or more cameras. Camera 71 comprises a lens, an image sensor, and a signal processing unit. The image sensor is composed of an image sensor such as a CMOS (Complementary Metal Oxide Semiconductor) sensor or a CCD (Charge-Coupled Device) sensor. Camera 71 is communicated with the control unit 80. Camera 71 images the entire upper surface of the substrate W held by the substrate holder 20 from an oblique upward angle. Specifically, camera 71 is positioned above the substrate W held by the substrate holder 20 within the chamber 10. Furthermore, camera 71 is positioned horizontally outward from the substrate W held by the substrate holder 20. The optical axis of camera 71 (a line perpendicular to the center of the image sensor) intersects the upper surface of the substrate W held by the substrate holder 20. The optical axis of camera 71 passes, for example, through the center of the substrate W or its vicinity. Please note that this camera configuration is just one example and can be changed as needed.

[0039] As shown in Figure 2, each camera 71 is covered by a cover 711. The cover 711 protects the camera 71 from the processing liquid and the gases generated by the evaporation of the processing liquid.

[0040] The illumination unit 73 illuminates the substrate W, which is the subject of the camera 71. The illumination unit 73 is provided to ensure the brightness necessary for imaging and to perform imaging without the influence of ambient light such as natural light. The illumination unit 73 is located on the same side as the camera 71 relative to the substrate holder 20.

[0041] Figure 3 is a block diagram showing the electrical connections between the control unit 80 and each part of the processing unit 102. The control unit 80 controls the operation of each part of the processing unit 102. As shown in Figure 3, the control unit 80 is a computer and has a processor 81 such as a CPU (Central Processing Unit), memory 82 such as RAM (Random-Access Memory), and storage unit 83 such as a hard disk drive.

[0042] As shown in Figure 3, the control unit 80 is communicated with the suction device 23, spin motor 32, nozzle drive unit 413, processing liquid supply unit 40 (e.g., valve), processing liquid collection unit 50 (e.g., lifting mechanism), camera 71, and lighting unit 73.

[0043] The memory unit 83 stores program P, which is a computer program for controlling the operation of each part of the processing unit 102. The memory unit 83 also stores the real image template Tm1 and the mirror image template Tm2. The real image template Tm1 and the mirror image template Tm2 are used in the nozzle position detection process, which will be described later. The real image template Tm1 and the mirror image template Tm2 will be described later.

[0044] The processor 81 reads the program P stored in the storage unit 83, loads it into the memory 82, and executes processing according to the program P. For example, the control unit 80 performs nozzle position detection processing and nozzle position adjustment processing, as will be described later. The program P may be recorded on a recording medium that the control unit 80 can read, such as a USB memory or optical or magnetic media.

[0045] <Nozzle position detection process and nozzle position adjustment process> Figure 4 shows the flow of the nozzle position detection process and nozzle position adjustment process performed by the control unit 80.

[0046] The control unit 80 controls the substrate holding unit 20 to hold the substrate W in the substrate holding unit 20 (step S1). The substrate W held in the substrate holding unit 20 may be a product substrate used to actually manufacture semiconductor devices, or it may be a dummy substrate used for adjustments during the startup of the device. The substrate W has a reflective surface Ws on its upper surface. The reflective surface Ws is preferably a mirror surface. That is, the reflective surface Ws is preferably a surface with a surface roughness at the nanometer level that is sufficiently smaller than the wavelength of light, on which incident light is reflected regularly (specular reflection), and on which the angle of reflection is equal to the angle of incidence. Because the reflective surface Ws is a mirror surface, the image of the reflected object can be clearly captured by the camera 71.

[0047] After step S1, the control unit 80 controls the nozzle drive unit 413 to move the nozzle 412 to a position near the substrate W (first position) (step S2). For example, the nozzle 412 is moved from a retracted position (a predetermined standby position) to a preset first position. Then, the control unit 80 acquires a first image Ph1 by imaging the nozzle 412 with the camera 71 (step S3).

[0048] Figure 5 is a schematic diagram showing the first image Ph1 acquired by camera 71. The imaging field of view of camera 71 includes, for example, the entire upper surface (reflective surface Ws) of the substrate W. The first image Ph1 includes the entire image of the reflective surface Ws of the substrate W, a nozzle real image 412a which is an image of the nozzle 412, and a nozzle mirror image 412b which is a mirror image of the nozzle 412 reflected on the reflective surface Ws. The nozzle mirror image 412b includes, for example, an image of the tip (lower end) of the nozzle 412, and has, for example, an image of the discharge port provided at the tip of the nozzle 412.

[0049] As shown in Figure 5, by including the entire reflective surface Ws in the imaging field of the camera 71, the position detection and adjustment of the nozzle 412 can be performed even when the nozzle 412 is positioned near the edge of the substrate W. However, it is not essential that the imaging field of the camera 71 includes the entire reflective surface Ws. For example, if the first position of the nozzle 412 is set near the center of the substrate W as shown in Figure 5, the imaging field of the camera 71 may be set to include only a portion of the substrate W near the center. The imaging field of the camera 71 only needs to be a region that simultaneously includes the nozzle real image 412a and the nozzle mirror image 412b in the first image Ph1.

[0050] Once the first image Ph1 is acquired, the control unit 80 detects the positions of the nozzle real image 412a and the nozzle mirror image 412b on the first image Ph1 (step S4). Position detection will be explained with reference to Figure 6.

[0051] Figure 6 is a conceptual diagram illustrating the position detection of the nozzle real image 412a and the nozzle mirror image 412b. Here, the control unit 80 performs position detection by pattern matching. Specifically, the control unit 80 performs pattern matching using a real image template Tm1 corresponding to the nozzle real image 412a and a mirror image template Tm2 corresponding to the nozzle mirror image 412b. The templates used are images showing the silhouette of the object to be detected. Through the pattern matching shown in Figure 6, a representative point Pn1 indicating the position of the nozzle real image 412a and a representative point Pn2 indicating the position of the nozzle mirror image 412b are identified. Representative points Pn1 and Pn2 are, for example, points corresponding to the tip of the nozzle 412. Representative points Pn1 and Pn2 are pre-set on the real image template Tm1 and the mirror image template Tm2. Representative points Pn1 and Pn2 are, for example, linked to coordinates on the images of the real image template Tm1 and the mirror image template Tm2.

[0052] Pattern matching is a method for detecting objects by comparing a template image with an image to be inspected and calculating the similarity. Similarity can be calculated using methods such as Normalized Cross-Correlation (NCC), or differences-based methods like SSD (Sum of Squared Differences) or SAD (Sum of Absolute Differences). The nozzle position (coordinates) can be identified from template images with high similarity. Preprocessing such as image normalization and filtering is performed as appropriate to mitigate the effects of noise and lighting variations. Furthermore, multiple types of template images or images with different rotation angles or sizes (image pyramids) may be used to accommodate image rotation and scaling changes.

[0053] Pattern matching is a relatively simple algorithm, so it does not require special hardware and can be implemented on a general-purpose CPU, and the processing time is stable. In addition, the relationship between pre-configuration parameter adjustments, such as adjusting the similarity threshold and setting the search range, and the detection results is relatively clear, making troubleshooting easier when problems occur.

[0054] Furthermore, location detection methods are not limited to pattern matching. For example, methods using deep learning (e.g., convolutional neural networks (CNNs)), feature point extraction (e.g., SIFT (Scale-Invariant Feature Transform)), and methods using edge and contour information can also be employed.

[0055] When the positions (representative points Pn1, Pn2) of the nozzle real image 412a and the nozzle mirror image 412b are detected, the control unit 80 calculates the first inter-image distance, which is the distance between these images on the image (Figure 4: Step S5). Specifically, as shown in Figure 6, the number of pixels between representative points Pn1 and Pn2 is calculated as the first inter-image distance. Note that the number of pixels indicating the inter-image distance is not limited to an integer and may include decimals. Furthermore, the calculation of the first inter-image distance may be performed after acquiring the second image Ph2, which will be described later.

[0056] After the first image Ph1 is acquired, the control unit 80 controls the nozzle drive unit 413 to move the nozzle 412 from the first position toward a pre-set target position in the vertical direction (i.e., toward or toward the substrate W) (Figure 4: Step S6). As a result, the substrate W moves from the first position to the second position. In step S6, the nozzle 412 may be moved a large amount so that its position approaches the target position. Alternatively, in step S6, the nozzle 412 may be moved a small amount by a specified amount. In this case, the target position will be reached by repeating the movement multiple times. The amount of movement of the nozzle 412 in step S6 can be set arbitrarily, but is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 2 mm or less.

[0057] After step S6, the control unit 80 takes an image with the camera 71 and acquires an image (Figure 4: step S7). The image acquired in step S7 is designated as the second image Ph2. The control unit 80 detects the nozzle real image 412a and the nozzle mirror image 412b on the acquired second image Ph2 (Figure 4: step S8). Furthermore, the control unit 80 calculates the second inter-image distance, which is the distance between the nozzle real image 412a and the nozzle mirror image 412b (Figure 4: step S9). Steps S8-S9 are the same as steps S4-S5, so their explanation is omitted.

[0058] After the first inter-image distance and the second inter-image distance are calculated, the control unit 80 calculates the inter-substrate nozzle distance, which is the distance from the substrate W to the nozzle 412 (step S10). Next, the principle for calculating the inter-substrate nozzle distance will be explained with reference to Figure 7.

[0059] Figure 7 is a conceptual diagram illustrating the relationship between the image distance and the distance between the substrate nozzles. For example, if the nozzle 412 is raised by 2 mm from the first position to the second position, the nozzle real image 412a moves upward (upward in the acquired image) by the equivalent of 2 mm on the image from the camera 71, and the nozzle mirror image 412b moves downward (downward in the acquired image) by the equivalent of 2 mm. As the amount of nozzle movement increases, the amount of change in the image distance also increases. In other words, there is a linear relationship between the amount of nozzle movement and the amount of change in the image distance (d2-d1).

[0060] Here, let t be the known nozzle movement, x1 be the distance between the substrate W and the first position nozzle 412, d1 be the first inter-image distance, and d2 be the second inter-image distance. Then, from the geometrical optical relationship, x1:(x1+t)=d1:d2 holds. That is, the distance x1 is expressed by the following equation.

[0061]

number

[0062] Furthermore, if we let x2 (= x1 + t) be the distance between the substrate nozzles from the substrate W to the second position nozzle 412, then the distance x2 is expressed by the following equation (2).

[0063]

number

[0064] As shown in equations (1) and (2), the value obtained by dividing the nozzle movement amount t by the change in inter-image distance (d2-d1) (=t / (d2-d1)) is a conversion coefficient k for converting the inter-image distances d1 and d2 into the substrate nozzle distances x1 and x2 in real space. By multiplying the inter-image distance by the conversion coefficient k, the substrate nozzle distance can be calculated. In other words, the position of the nozzle 412 relative to the substrate W can be calculated from the inter-image distance.

[0065] Returning to Figure 4, the control unit 80 determines whether the nozzle 412 has reached the target position (step S11). Specifically, it determines whether the current distance between substrate nozzles calculated in step S10 has reached the substrate nozzle distance corresponding to a predetermined target position (target distance L). In this determination, an allowable range ±α is set in advance for the target distance L. Then, if the current distance between substrate nozzles has not reached the lower limit of the target distance (=L-α), the control unit 80 determines that the nozzle 412 has not reached the target position and executes steps S6 to S11 again. In other words, the control unit 80 repeatedly executes steps S6-S11 until it is determined that the nozzle 412 has reached the target position.

[0066] If the inter-image distances d1 and d2 are the number of pixels between representative points Pn1 and Pn2, the distance per pixel can be calculated from the value obtained by doubling the amount of movement t of the nozzle 412 in equation (1) or (2) above and dividing it by the change in the inter-image distance (d2-d1) (=2t / (d2-d1)). In other words, the distance per pixel is the distance (length) corresponding to the vertical side of the pixel. By calculating the distance per pixel in this way, or by using the number of pixels for the inter-image distance, more accurate positioning can be achieved. Alternatively, the number of pixels between x1 (or x2) and the target distance L (or L±α) can be calculated by comparing the calculated x1 (or x2) with the target distance L (or L±α). By moving the nozzle 412 by the number of pixels that exist between x1 (or x2) and the target distance L (or L±α), the position of the nozzle 412 can be accurately adjusted. For example, if there is a difference of 3 pixels between x2 and the target distance L, the nozzle 412 can be moved by an amount calculated by integrating the distance per pixel with the distance of 3 pixels.

[0067] If it is determined in step S11 that the nozzle 412 has reached the target position, the control unit 80 stores the position information (coordinates and amount of movement) of the nozzle 412 at that time in the storage unit 83 (step S12). When actually processing the substrate W for the product, the control unit 80 controls the nozzle drive unit 413 using the position information stored in step S12 as the target value. This allows the nozzle 412 to be positioned at the target position with high precision.

[0068] As described above, according to this embodiment, the distance x1 and x2 between the substrate nozzle can be calculated by using the known amount of movement t when the nozzle 412 is moved and the inter-image distances d1 and d2 obtained from images captured by the camera before and after the movement. Therefore, the position (height) of the nozzle 412 relative to the substrate W can be detected with high accuracy. In this way, by simultaneously capturing images of the nozzle 412 and its mirror image reflected on the substrate W, high-precision position adjustment can be performed with a single camera 71 configuration. Furthermore, by including the entire substrate W in the imaging field of view, the nozzle 412 can be aligned to the target position at any location on the substrate W.

[0069] <2. Variant Example> Although embodiments have been described above, the present invention is not limited to those described above, and various modifications are possible.

[0070] For example, in step S10 shown in Figure 4, the control unit 80 may recalculate the conversion coefficient k each time a new inter-image distance is obtained. Alternatively, the control unit 80 may determine whether the recalculated conversion coefficient k is an abnormal value based on a predetermined criterion (e.g., a threshold). This allows for the detection of errors in the device (e.g., pattern matching errors, nozzle movement errors, etc.). Furthermore, if an abnormality is determined, the control unit 80 may notify the outside via an output device (e.g., a display, speaker, warning light, etc.) notified to the outside.

[0071] The processing unit 102 may be provided with a mechanism for moving the camera 71. By positioning the camera appropriately, the camera and its mirror image can be properly captured. Even if the accuracy of the camera movement mechanism is poor, the above nozzle position detection method can accurately detect the camera position regardless of the movement error of the camera 71.

[0072] Although the above-described substrate processing apparatus 100 is configured as a coating apparatus, it may also be configured as a cleaning apparatus for cleaning the substrate W. In the case of a cleaning apparatus, examples of processing liquids discharged from the nozzle 412 include SPM cleaning liquid (a mixture of sulfuric acid and hydrogen peroxide), SC-1 cleaning liquid (a mixture of ammonia water, hydrogen peroxide, and pure water), SC-2 cleaning liquid (a mixture of hydrochloric acid, hydrogen peroxide, and pure water), DHF cleaning liquid (dilute hydrofluoric acid), and pure water (deionized water). Furthermore, in a cleaning apparatus, the nozzle 412 may be a so-called two-fluid nozzle that mixes the processing liquid with a pressurized gas to generate droplets and sprays the mixed fluid of these droplets and gas onto the substrate W.

[0073] In the above embodiment, the case in which the substrate processing apparatus is an apparatus for processing semiconductor wafers was described. However, the substrate to be processed may also be a substrate for electronic devices such as a glass substrate for liquid crystal display devices, a glass substrate for photomasks, a glass substrate for plasma displays, a glass or ceramic substrate for magnetic or optical disks, a glass substrate for organic EL, a glass substrate or silicon substrate for solar cells, or other flexible substrates or printed circuit boards.

[0074] Although this invention has been described in detail, the above description is illustrative in all respects, and the invention is not limited thereto. It is understood that countless variations not illustrated can be conceived without falling outside the scope of this invention. The components described in each of the above embodiments and variations can be combined or omitted as appropriate, as long as they do not contradict each other. [Explanation of symbols]

[0075] 20: Board holding part 71: Camera 80: Control Unit (Computer) 412: Nozzle 412a: Nozzle real image 412b: Nozzle mirror image P: Program Ph1: First image Ph2: Second image Tm1: Real image template Tm2: Mirror image template W: Circuit board Ws: Reflective surface

Claims

1. A nozzle position detection method, a) A step of holding a substrate having a reflective surface in a substrate holding part, b) A step of acquiring a first image including the nozzle and the mirror image of the nozzle by imaging the nozzle positioned at the first position and the mirror image of the nozzle reflected on the reflective surface of the substrate, c) A step of obtaining a first inter-image distance between the real image of the nozzle and the mirror image of the nozzle in the first image, d) After step b), a step of moving the nozzle from the first position to the second position in the vertical direction of the substrate, e) A step of acquiring a second image including the nozzle and the mirror image of the nozzle by imaging the nozzle at the second position and the mirror image of the nozzle reflected on the reflective surface of the substrate. f) A step of obtaining the second inter-image distance between the real image of the nozzle and the mirror image of the nozzle in the second image, g) A step of calculating the substrate-nozzle distance from the substrate to the nozzle using the amount of movement when the nozzle is moved from the first position to the second position in step d), the first inter-image distance, and the second inter-image distance. A nozzle position detection method, including the above.

2. A nozzle position detection method according to claim 1, The nozzle position detection method includes step g) a step of calculating a conversion coefficient to convert the inter-image distance between the real image of the nozzle and the mirror image of the nozzle into the inter-nozzle distance between the substrate nozzles.

3. A nozzle position detection method according to claim 2, The first inter-image distance is the number of pixels between the real image of the nozzle and the mirror image of the nozzle in the first image. The second inter-image distance is the number of pixels between the real image of the nozzle and the mirror image of the nozzle in the second image. A nozzle position detection method in which the conversion coefficient is the value obtained by dividing the amount of movement of the nozzle by the amount of change in the first inter-image distance and the second inter-image distance.

4. A nozzle position detection method according to any one of claims 1 to 3, The aforementioned step c) is, c-1) A step of detecting the positions of the real image and the mirror image of the nozzle in the first image by pattern matching, c-2) A step of obtaining the first inter-image distance using the detection result of step c-1), A nozzle position detection method, including the above.

5. A method for adjusting the nozzle position, A) A step of calculating the distance between substrate nozzles using the nozzle position detection method described in any one of claims 1 to 3, B) A step of determining whether the distance between substrate nozzles calculated in step A) has reached a predetermined target distance, C) If it is determined in step B) that the distance between the substrate nozzles has not reached the target distance, the step of moving the nozzles so that the distance between the substrate nozzles approaches the target distance. A method for adjusting the nozzle position, including the method described above.

6. A nozzle position adjustment method according to claim 5, In step C), a nozzle position adjustment method is provided, in which the nozzle is moved to approach the target distance based on the number of pixels present between the substrate nozzle distance and the target distance.

7. A computer program that can be executed by a computer, A computer program for causing the computer to perform the steps of the nozzle position detection method described in claim 1 or claim 2.

8. A substrate processing apparatus, A substrate holding section that holds the substrate, A nozzle for discharging the processing liquid, A nozzle drive unit for moving the aforementioned nozzle, Imaging unit, A control unit that controls the nozzle drive unit, Equipped with, The control unit performs the nozzle position detection method according to any one of claims 1 to 3, in a substrate processing apparatus.

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