Substrate processing apparatus and substrate processing method

Abstract

To enable a liquid column to be detected with a good S / N, even when the liquid supplied in columnar form from a nozzle is transparent.SOLUTION: A substrate processing device pertaining to the present invention comprises: a substrate holding unit for almost horizontally holding a substrate; a nozzle for ejecting a liquid in columnar form toward the substrate and located at a processing position that faces the upper surface of the substrate being held by the substrate holding unit; an illumination unit for emitting illumination light toward a liquid column formed by the liquid between the nozzle and the substrate; and a light receiving unit for receiving light from the liquid column and provided on the side of the processing position that is opposite the illumination unit across the nozzle. The illumination unit emits, as illumination light, converged light having been converged so as to include a convergent point in the liquid column or parallel light larger in beam width than the width of the liquid column in the width direction perpendicular to the incidence direction of illumination light, and the light receiving unit is provided at a position which a bundle of rays of illumination light having been emitted from the illumination unit and passed through the position where the liquid column is formed does not enter.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a substrate processing technology for processing a substrate such as a semiconductor wafer with a liquid, and particularly to a technology for optically detecting a liquid column of a liquid discharged from a nozzle disposed on the substrate toward the substrate.

Background Art

[0002] In a substrate processing technology for supplying a liquid to the upper surface of a substrate held in a horizontal posture to process the substrate, for the purpose of checking whether a nozzle for discharging the liquid toward the substrate is disposed at an appropriate position, or whether the liquid is discharged from the nozzle at an appropriate timing, etc., a technology for optically detecting the nozzle or the liquid discharged from the nozzle may be used. For example, in the substrate processing apparatus described in Patent Document 1, a liquid flowing down in a columnar shape is imaged by a camera that includes a space where the liquid between the nozzle and the substrate flows down in the imaging field of view, and a liquid column formed by the liquid is detected from the image, and its width and discharge position are compared with a predetermined reference value to determine the suitability of the discharge state.

[0003] In the technology described in Patent Document 1, a camera for imaging the liquid column and an illumination unit are disposed close to each other on a swing arm and configured to move integrally. Then, with these positioned in the vicinity of a nozzle for discharging the liquid, the camera receives the reflected light of the illumination light incident on the liquid column.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Liquids ejected from nozzles are generally often transparent, and most of the illumination light incident on the liquid column passes through the liquid column. Therefore, it cannot be said that the amount of reflected light incident on the camera is sufficient, and the contrast of the liquid column in the image is not high. For example, regarding the Michelson contrast value, which is an index for quantifying image contrast, the current situation is that only a value slightly exceeding 0.2, which is generally the lower limit required for image measurement, can be ensured.

[0006] As methods for enhancing contrast, for example, long-time exposure and increasing the gain of the detection system can be considered. However, since these methods also increase the amount of received light from sources other than the liquid column, the brightness of the image saturates, making it unsuitable for imaging objects other than the liquid column, such as nozzles. Also, an increase in noise may cause problems in subsequent image processing.

[0007] Thus, when optically detecting a liquid ejected from a nozzle, it is not easy to obtain a good signal-to-noise ratio (S / N ratio). In particular, in cases where the distance between the illumination unit and the liquid column is large, such as in a case where the illumination unit and the imaging unit are provided outside the substrate, or when the distance between the nozzle and the substrate when ejecting the liquid is small, it becomes even more difficult to make sufficient illumination light of the liquid column incident on the liquid column, so the above problems are prominent.

[0008] This invention has been made in view of the above problems, and an object thereof is to provide a technique that enables detection of a liquid column with a good S / N ratio even when the liquid supplied columnarly from a nozzle to a substrate is transparent.

Means for Solving the Problems

[0009] The substrate processing apparatus according to the present invention includes a substrate holding unit that holds a substrate substantially horizontally, a nozzle disposed at a processing position facing the upper surface of the substrate held by the substrate holding unit and discharging liquid in a columnar shape toward the substrate, an illumination unit that emits illumination light toward a liquid column formed between the nozzle and the substrate by the liquid, and a light receiving unit provided on the side opposite to the illumination unit with the nozzle at the processing position interposed therebetween and receiving light from the liquid column.

[0010] In one aspect of the present invention, the illumination unit emits, as the illumination light, convergent light converged so that a convergence point is included in the liquid column. In another aspect of the present invention, the illumination unit emits, as the illumination light, parallel light having a beam width larger than the width of the liquid column in a width direction perpendicular to the incident direction of the illumination light. a light having a shape symmetrical with respect to a vertical plane including the center of the liquid column and the center of the light receiving portion, and having a light flux of the illumination light In these aspects, the light receiving unit is provided at a position where a light beam of the illumination light emitted from the illumination unit and passing through the position where the liquid column is formed does not enter.

[0011] In one aspect of the substrate processing method according to the present invention, there are provided a step of discharging liquid in a columnar shape toward a substrate from a nozzle disposed at a processing position facing the upper surface of the substrate held substantially horizontally, and a step of emitting illumination light from an illumination unit toward a liquid column formed between the nozzle and the substrate by the liquid and receiving light from the liquid column by a light receiving unit provided on the side opposite to the illumination unit with the nozzle at the processing position interposed therebetween. Here, the illumination unit emits, as the illumination light, convergent light converged so that a convergence point is included in the liquid column is emitted as the illumination light or parallel light having a beam width larger than the width of the liquid column in a width direction perpendicular to the incident direction of the illumination light a light having a shape symmetrical with respect to a vertical plane including the center of the liquid column and the center of the light receiving portion, and having a light flux as the illumination light. The light receiving unit is provided at a position where a light beam of the illumination light emitted from the illumination unit and passing through the position where the liquid column is formed does not enter.

[0012] In the invention configured as described above, the light-receiving part is arranged at a position where the luminous flux of the illumination light emitted from the illumination part does not enter. Therefore, in a state where no liquid is discharged from the nozzle and no liquid column is formed, the illumination light is not received by the light-receiving part. On the other hand, when liquid is continuously discharged from the nozzle, a liquid column is formed between the nozzle and the substrate by the liquid. At this time, the illumination light is bent in various directions by refraction and reflection by the liquid column, and at least a part of it reaches the light-receiving part and is received.

[0013] Thus, in the present invention, when there is a liquid column between the nozzle and the substrate, the refracted light of the illumination light by the liquid column reaches the light-receiving part. Therefore, compared with a configuration that receives the reflected light from the surface of the transparent liquid column, the amount of received light can be increased, and the S / N ratio can be improved. In addition, since the illumination light does not directly enter the light-receiving part, it is avoided that the light from the liquid column is masked by the illumination light. This also contributes to the improvement of the S / N ratio. Furthermore, by increasing the difference in the amount of received light between the case where a liquid column is formed and the case where it is not, for example, it is possible to easily detect the presence or absence of the liquid column based on the amount of received light.

Advantages of the Invention

[0014] As described above, according to this invention, since the illumination light does not directly enter the light-receiving part and is configured such that the refracted light when a liquid column is formed between the nozzle and the substrate is received by the light-receiving part, even if the liquid is transparent, it is possible to detect the liquid column with a good S / N ratio.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0016] Hereinafter, an outline of a substrate processing apparatus to which the present invention is applicable will be described. Hereinafter, the substrate refers to various substrates such as a semiconductor substrate, a glass substrate for a photomask, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, and a substrate for a magneto-optical disk. Hereinafter, a substrate processing system mainly used for processing a semiconductor substrate will be taken as an example and described with reference to the drawings, but the present invention is also applicable to processing of various substrates exemplified above.

[0017] FIG. 1 is a diagram showing a schematic configuration of a substrate processing system according to an embodiment of the present invention. More specifically, FIG. 1 is a plan view of one aspect of a substrate processing system including a substrate processing apparatus to which the present invention can be preferably applied. This substrate processing apparatus 1 includes substrate processing units 1A, 1B, 1C, 1D that can each independently execute a predetermined process on a substrate, and an indexer unit 1E in which an indexer robot (not shown) for transferring the substrate between these substrate processing units 1A to 1D and the outside is arranged, and a control unit 80 that controls the operation of the entire system. Note that the number of arranged substrate processing units is arbitrary, and a configuration in which four substrate processing units arranged in the horizontal direction are taken as one stage and a plurality of such stages are stacked in the vertical direction may also be used.

[0018] Although the layouts of the respective parts of the substrate processing units 1A to 1D are somewhat different depending on their arrangement positions in the substrate processing apparatus 1, the components included in each unit and their operations are the same as each other. Therefore, below, the configuration and operation of one of these substrate processing units, 1A, will be described, and detailed descriptions of the other substrate processing units 1B to 1D will be omitted.

[0019] FIG. 2 is a plan view showing the structure of one substrate processing unit. The substrate processing unit 1A is a single-wafer wet processing unit for performing wet processing such as cleaning or etching on a disk-shaped substrate S such as a semiconductor wafer with a processing liquid. This substrate processing unit 1A includes a chamber 90 in which a fan filter unit (FFU) is disposed at the ceiling portion.

[0020] A substrate holding portion 10 is provided in the processing space SP inside the chamber 90. This substrate holding portion 10 holds and rotates the substrate S in a substantially horizontal posture with the substrate surface facing upward. This substrate holding portion 10 has a spin chuck in which a disk-shaped spin base 11 having an outer diameter slightly larger than that of the substrate S and a rotation support shaft (not shown) extending in a substantially vertical direction are integrally coupled. The rotation support shaft is connected to a rotation mechanism such as a motor, and the spin base 11 can rotate around the rotation axis (vertical axis) by driving from the control unit 80.

[0021] Near the peripheral edge portion of the spin base 11, a plurality of chuck pins 114 for gripping the peripheral end portion of the substrate S are erected. Three or more chuck pins 114 may be provided (six in this example) in order to securely hold the circular substrate S, and they are arranged at equal angular intervals along the peripheral edge portion of the spin base 11. Each of the chuck pins 114 is configured to be switchable between a pressing state in which it presses the outer peripheral end face of the substrate S and a released state in which it is separated from the outer peripheral end face of the substrate S.

[0022] A splash guard 20 is provided so as to be movable up and down along the rotation axis of the spin base 11 so as to surround the periphery of the substrate S held in a horizontal posture on the spin base 11. The splash guard 20 has a shape that is substantially rotationally symmetric with respect to the rotation axis, and is arranged concentrically with the spin base 11 to receive the processing liquid scattered from the substrate S. Then, a guard lifting mechanism (not shown) provided in the control unit 80 raises and lowers the splash guard 20. At the upper position where the upper end of the splash guard 20 is located above the upper surface of the substrate S, it is possible to collect the processing liquid such as the chemical solution and the rinse solution scattered from the rotating substrate S. Also, at the lower position where the upper end of the splash guard 20 is located below the upper surface of the substrate S, the substrate S is exposed, and it is possible to carry out the substrate S by the hand of the external transfer robot that enters the chamber 90 from the outside as necessary.

[0023] At least one fluid supply unit for supplying various processing fluids such as chemical solutions such as etching solutions, rinse solutions, solvents, pure water, and DIW (deionized water) to the substrate S is provided around the splash guard 20. In this example, as shown in FIG. 2, three sets of fluid supply units 30, 40, and 50 are provided. The fluid supply unit 30 includes a rotation shaft 31 that is driven and controlled by the control unit 80 and is configured to be rotatable about a vertical axis, an arm 32 that extends horizontally from the rotation shaft 31, and a nozzle 33 that is attached downward at the tip of the arm 32. When the rotation shaft 31 rotates in response to a control command from the control unit 80, the arm 32 swings about the vertical axis, and thereby the nozzle 33 moves between a retracted position outside the splash guard 20 and a position above the rotation center of the substrate S. The nozzle 33 discharges a predetermined processing fluid supplied from a fluid supply source (not shown) of the control unit 80 while being positioned above the substrate S, and supplies it to the surface of the substrate S.

[0024] Similarly, the fluid supply unit 40 includes a rotating shaft 41 that rotates in response to a control command from the control unit 80, an arm 42 connected thereto, and a nozzle 43 provided at the tip of the arm 42 for discharging the processing fluid. Further, the fluid unit 50 includes a rotating shaft 51 that rotates in response to a control command from the control unit 80, an arm 52 connected thereto, and nozzles 53 to 55 provided at the tip of the arm 52 for discharging the processing fluid. That is, three nozzles 53, 54, and 55 are arranged side by side on the arm 52 of the fluid supply unit 50. Further, an auxiliary illumination unit 6 is provided on the arm 53. The auxiliary illumination unit 6 will be described in detail later.

[0025] Note that the number of fluid supply units is not limited to the above and may be increased or decreased as necessary. Also, the configuration of each fluid supply unit is not limited to the above and is arbitrary. Further, the type of processing fluid supplied from the fluid supply source of the control unit 80 to each of the above nozzles is also arbitrary, and gases such as nitrogen gas and dry air may be used in addition to the above-described processing liquid. Also, a plurality of nozzles may discharge different processing fluids from each other, or may discharge the same type of processing fluid.

[0026] Note that the two-dot chain line in FIG. 2 indicates the movement trajectories of the nozzles 33, 43, and 53. As can be seen therefrom, due to the swinging of the arms 32, 42, and 52, the nozzles 33, 43, and 53 to 55 move along an arc on a horizontal plane that reaches from the retracted position beyond the rotation center of the substrate S to the peripheral edge of the substrate S on the side far from the retracted position. Discharge of the processing liquid from each nozzle is possible in either a state where the nozzle is positioned and fixed above the substrate S or a state where the nozzle moves above the substrate S. Thereby, various wet processes can be realized.

[0027] With the substrate S rotating at a predetermined rotational speed due to the rotation of the spin base 11, these fluid supply units 30, 40, 50 position the nozzles 33, 43, 53 above the substrate S in sequence and supply the processing liquid to the substrate S, thereby executing processing on the substrate S. Depending on the purpose of the processing, different processing fluids may be ejected from each of the nozzles 33, 43, 53, or the same processing fluid may be ejected. Also, two or more types of processing fluids may be ejected from one nozzle. The processing fluid supplied near the rotation center of the substrate S spreads outward due to the centrifugal force accompanying the rotation of the substrate S and is finally flung laterally from the peripheral portion of the substrate S. The liquid scattered from the substrate S is received and collected by the splash guard 20.

[0028] Furthermore, in the substrate processing unit 1A, an illumination unit 71 for illuminating the inside of the processing space SP and a camera 72 for imaging the inside of the chamber are provided adjacent to each other. The illumination unit 71 uses, for example, an LED lamp as a light source and supplies the illumination light necessary for imaging by the camera 72 into the processing space SP. The camera 72 is provided at a position higher than the substrate S in the vertical direction, and its imaging direction (i.e., the optical axis direction of the imaging optical system) is set obliquely downward toward the approximate rotation center of the surface of the substrate S so as to image the upper surface of the substrate S. Thereby, the camera 72 encompasses the entire surface of the substrate S held by the spin base 11 within its field of view. Horizontally, the range sandwiched by the broken lines in FIG. 2 is included in the field of view of the camera 72.

[0029] Note that the illumination unit 71 and the camera 72 may be provided inside the chamber 90, or may be provided outside the chamber 90 and configured to perform illumination or imaging on the substrate S through a transparent window provided in the chamber 90. From the viewpoint of preventing the adhesion of the processing liquid and exposure to the processing atmosphere, it is preferable that these are provided outside the chamber 90.

[0030] The image data acquired by the camera 72 is provided to the control unit 80. The control unit 80 performs appropriate image processing on the image data, such as correction processing and pattern matching processing, and based on the results, detects the position of the nozzle and the discharge status of the processing fluid. For example, as will be described later, the control unit 80 can determine the discharge state of the processing liquid from the nozzles 53 to 55 of the fluid supply unit 50 based on the image data acquired by the camera 72.

[0031] In the control unit 80 of this substrate processing apparatus 1, in order to execute the above-described various processes, a CPU that executes a predetermined processing program to control the operations of each unit, a memory for storing and saving the processing program executed by the CPU and data generated during processing, a display unit for notifying the user of the progress of processing and the occurrence of abnormalities as necessary, etc. are provided. Note that the control unit 80 may be provided individually for each substrate processing unit 1A to 1D, or may be provided only in one set in the substrate processing apparatus 1 and configured to comprehensively control the substrate processing units 1A to 1D.

[0032] In the substrate processing unit 1A configured as described above, at least the fluid supply unit 50 is used for the bevel processing of the substrate S. That is, the fluid supply unit 50 supplies a processing liquid to a bevel portion including an inclined surface provided at the peripheral edge of the substrate S and processes the portion. For this purpose, the fluid supply unit 50 discharges the processing liquid with the nozzles 53 to 55 positioned above the peripheral edge of the substrate S.

[0033] FIG. 3 is a diagram showing the arrangement of each part in the bevel processing. Among them, FIG. 3(a) is a plan view showing the positional relationship between the substrate S, the fluid supply unit 50, the lighting unit 71, and the camera 72 during the execution of the bevel processing. FIG. 3(b) is a side view corresponding to the cross section taken along line A-A in FIG. 3(a), and FIG. 3(c) is a partial enlarged view thereof. When the bevel processing is executed, the fluid supply unit 50 rotates and positions the arm 52 so that the nozzles 53 to 55 are each positioned above the peripheral edge of the substrate S. The positions of the nozzles 53 to 55 at this time are hereinafter referred to as "processing positions".

[0034] Each of the nozzles 53 to 55 discharges a processing liquid at an appropriate timing according to a predetermined processing recipe while being positioned at the processing position. Thereby, the bevel portion B of the substrate S is processed. For example, an etching removal process of a metal film formed on the bevel portion B, a resist film removal process, and a subsequent cleaning process and the like can be executed as bevel processing.

[0035] When the nozzles 53 to 55 are respectively positioned at the processing position, the illumination unit 71 and the camera 72 are located on the side opposite to the nozzles 53 to 55 with the substrate S interposed therebetween. As shown in FIG. 3(b) and a partial enlarged view thereof, FIG. 3(c), the nozzles 53 to 55 are arranged in proximity to and facing the vicinity of the peripheral edge portion of the upper surface of the substrate S. Typically, the distance Dn between the lower ends of the nozzles 53 to 55 and the upper surface of the substrate S is about 1 mm to several mm.

[0036] From the nozzles 53 to 55 arranged in proximity to and facing the substrate S in this manner, a processing liquid corresponding to the purpose of the processing is continuously discharged toward the bevel portion B. Therefore, a columnar liquid column C is formed by the processing liquid between the nozzles 53 to 55 and the substrate S. The diameter Dc of the liquid column C is 1 mm or less, for example, 0.2 mm to 0.3 mm.

[0037] As shown in FIG. 3(b), the camera 72 is arranged with its optical axis slightly downward so as to overlook the upper surface of the substrate S from above, and the space where the liquid column C is formed between the nozzles 53 to 55 and the substrate S is also included in its imaging field of view. Therefore, it is possible to determine the discharge state of the processing liquid supplied from the nozzles 53 to 55 to the substrate S from the image captured by the camera 72. Specifically, the control unit 80 detects the liquid column C from the image captured by the camera 72, and based on the result, determines the presence or absence and the discharge amount of the liquid discharged from the nozzles 53 to 55.

[0038] As image processing for detecting the liquid column C from the captured image, there are already known techniques, and for example, the method described in Patent Document 1 can be applied. Therefore, the detailed content of the image processing is omitted here.

[0039] On the other hand, in this embodiment, for the nozzles 53 to 55 positioned at the processing position, the illumination unit 71 and the camera 72 are arranged on the opposite side across the substrate S. Thus, when the distance between the nozzles 53 to 55 and the liquid column C, which are the imaging targets, and the illumination unit 71 and the camera 72 is large, it becomes difficult to image the liquid column C with a high signal-to-noise ratio. This is because the liquid discharged from the nozzles 53 to 55 is generally transparent and transmits the illumination light, so the liquid column C cannot be imaged with sufficient brightness by illumination from a distance.

[0040] In order to image the liquid column C brightly, measures such as increasing the amount of illumination light emitted by the illumination unit 71, increasing the exposure time during imaging, and increasing the sensitivity of the camera 72 can be considered. However, an increase in the amount of illumination light or the exposure time causes the brightness of the objects to be imaged other than the liquid column C to saturate. For this reason, it is difficult to make it compatible with the detection of, for example, the surface state of the substrate S and the nozzle position other than the liquid column C. Also, even if the sensitivity on the camera 72 side is improved, for example, by increasing the gain of the signal detection system, the image noise also increases, so it does not necessarily lead to an improvement in the signal-to-noise ratio.

[0041] To address such problems, in this embodiment, an auxiliary illumination unit 6 for illuminating the liquid column C is provided. That is, as shown in FIG. 2, the auxiliary illumination unit 6 is attached to the arm 52 of the fluid supply unit 50. Therefore, the auxiliary illumination unit 6 moves integrally with the nozzles 53 to 55 by the rotation of the arm 52. As shown in FIGS. 3(a) and 3(b), when the nozzles 53 to 55 are positioned at the processing position above the peripheral edge of the substrate S, the auxiliary illumination unit 6 is located on the side opposite to the camera 72 with the nozzles 53 to 55 in between.

[0042] As shown in FIG. 3(c), the auxiliary illumination unit 6 causes auxiliary illumination light L to be incident on the liquid column C formed in the space between the nozzles 53 to 55 and the substrate S. Thereby, it becomes possible to increase the brightness of the liquid column C in the image captured by the camera 72. However, since the auxiliary illumination unit 6 is disposed at a position facing the camera 72 directly, and the liquid column C formed of a transparent liquid transmits the illumination light L, it is necessary to prevent the illumination light L emitted from the auxiliary illumination unit 6 from directly entering the camera 72.

[0043] In the present embodiment, the problem is addressed as follows. Note that a plurality of nozzles 53 to 55 are provided on the arm 52, and the auxiliary illumination unit 6 also has a configuration corresponding to the plurality of nozzles. However, for the sake of principle explanation below, first, the case where there is one nozzle, that is, only one liquid column C is formed, will be taken up, and then the correspondence to a plurality of nozzles will be described.

[0044] FIG. 4 is a diagram illustrating two modes of illumination of a liquid column by the auxiliary illumination unit, and more specifically, is a plan view showing the path of the illumination light L emitted from the auxiliary illumination unit 6. Among these, FIG. 4(a) shows the first mode of liquid column illumination, and FIG. 4(b) shows the second mode of liquid column illumination. In these modes, the illumination light L is made incident on the liquid column C from an oblique direction with respect to an axis (hereinafter referred to as the "imaging axis") connecting the center of the liquid column C and the center of the imaging field of the camera 72 on the plan view, which is indicated by a one-dot chain line. In these figures, the arrows indicate the traveling direction of the light.

[0045] In the first mode shown in FIG. 4(a), the illumination light L is convergent light converged so that the center of the liquid column C becomes the convergence point. When the liquid column C does not exist, that is, when liquid is not being ejected from the nozzle, the incident direction of the illumination light L and the spread of its light flux are set so that the straight-traveling illumination light L does not enter the camera 72. It can also be said that the camera 72 is disposed at a position deviated from the optical path of the illumination light L.

[0046] As will be described in detail later, when liquid is ejected from the nozzle and a liquid column C is formed, the illumination light L incident on the liquid column C is bent in various directions by reflection on the surface of the liquid column C and refraction when passing through the liquid column C. When such light enters the camera 72, an image of the liquid column C is captured. The transparency of the liquid column C increases the amount of such reflected light and refracted light, and as a result, the signal-to-noise ratio can be improved.

[0047] For example, if the purpose is simply to determine the presence or absence of liquid ejection from the nozzle, it is sufficient to be able to distinguish between a state where there is no liquid column C and the illumination light L does not enter the camera 72 at all, and a state where the reflected and refracted light by the liquid column C enters the camera 72. Therefore, the robustness of the determination can be improved compared to a method of detecting the image of the liquid column by image processing from an image with low contrast.

[0048] On the other hand, for example, the diameter of the liquid column C (the width of the liquid column C in the two-dimensional image) changes according to the amount of liquid ejected. Therefore, if the width of the liquid column C can be accurately detected from the image, it becomes possible to estimate not only the presence or absence of liquid ejection but also the ejection amount. For this purpose, as shown by the solid line and the dotted line in Fig. 4(a), it is desirable that the illumination lights L and L' enter the liquid column C from two directions sandwiching the imaging axis. More specifically, it is preferable that each of the illumination lights L and L' travels along an optical path symmetric with respect to a vertical plane (a plane perpendicular to the paper surface in the figure) including the imaging axis indicated by the dashed-dotted line and enters the liquid column C. Furthermore, it is more preferable that the cross-sectional shape of each light beam of the illumination lights L and L' is symmetric with respect to the vertical plane including the imaging axis.

[0049] In this way, when looking at the liquid column C from the camera 72, both side surfaces of the liquid column C are illuminated under the same illumination conditions, so a clear image of the liquid column C can be obtained. As a result, it becomes possible to accurately detect the width of the liquid column C from the image.

[0050] Regarding the configuration of the auxiliary illumination unit 6 for realizing the first aspect of the liquid column illumination shown in Fig. 4(a), and more preferable conditions for ensuring that at least one of the reflected light and the refracted light from the liquid column C enters the camera 72, it will be described in detail later with reference to Figs. 5 and 6.

[0051] In the second aspect of the liquid column illumination shown in Fig. 4(b), the illumination light L is irradiated onto the liquid column C as parallel light having a beam width wider than the width of the liquid column C in a plan view. Also in this case, the incident direction and the beam width of the illumination light L are set so that the illumination light L that travels straight without the presence of the liquid column C does not enter the camera 72. Further, similar to the first aspect, as shown by the solid line and the dotted line, the illumination lights L and L' may be incident on the liquid column C from two directions across the vertical plane including the imaging axis.

[0052] Regarding the configuration of the auxiliary illumination unit 6 for realizing the second aspect of the liquid column illumination shown in Fig. 4(b), and more preferable conditions for ensuring that at least one of the reflected light and the refracted light from the liquid column C enters the camera 72, it will be described in detail later with reference to Fig. 7.

[0053] In the following description, when it is necessary to distinguish between the two aspects of the auxiliary illumination unit 6, they will be distinguished by attaching the reference sign 6a to the first aspect and the reference sign 6b to the second aspect, respectively.

[0054] Fig. 5 is a diagram showing a configuration example for realizing the liquid column illumination of the first aspect. More specifically, Fig. 5(a) is a plan view showing a configuration example of the auxiliary illumination unit 6a of the first aspect, with a ray diagram when there is no liquid column added. Fig. 5(b) is a ray diagram when the liquid column C is present.

[0055] In Fig. 5, the area marked with low-density dots indicates the optical path of the light emitted from the light source. Also, the area marked with higher-density dots indicates the optical path of the light that is reflected or refracted on the surface and inside of the liquid column C and then enters the camera 72 when the liquid column C is formed. The same applies to Figs. 6 and 7 to be described later.

[0056] As shown in Fig. 5(a), the auxiliary illumination unit 6a includes a point light source 611 and an illumination optical system 610. The illumination optical system 610 includes a collimator lens 612, a converging lens 613, and a light-shielding aperture 614. The point light source 611 is, for example, an LED (Light Emitting Diode), and emits visible light, for example, red light, in various directions. The collimator lens 612 converts the light emitted from the point light source 611 into parallel light. For this purpose, the point light source 611 is arranged at a position separated from the collimator lens 612 by a distance corresponding to its focal length f1.

[0057] The converging lens 613 converges the parallel light toward the position where the liquid column is formed (more precisely, the position corresponding to the center when the liquid column C is formed) P. For example, the center of the liquid column C can be set as the convergence point. That is, the distance between the position P where the liquid column is formed when the liquid is discharged from the nozzle and the converging lens 613 is separated by a distance corresponding to the focal length f2 of the converging lens 613. Note that for the converging light, it is not necessary to converge exactly at the convergence point in a strict sense. That is, at the position where the liquid column C is formed, it is sufficient that the spot size of the converging light is narrowed down to about the same width as the liquid column C.

[0058] The collimator lens 612 and the converging lens 613 that form the illumination optical system 610 are arranged coaxially with each other, and the point light source 611 is also arranged on this axis. For example, the optical axis of this illumination optical system 610 can be made coaxial with the imaging axis indicated by the dashed-dotted line, but it is not limited to this.

[0059] A light-shielding aperture 614 is disposed on the optical path of collimated light between the collimator lens 612 and the converging lens 613. The light-shielding aperture 614 shields a part of the optical path of the collimated light generated by the collimator lens 612. For the light-shielding aperture 614, for example, it can be disposed at a position conjugate to the point light source 611 with respect to the collimator lens 612 and at a position conjugate to the converging point with respect to the converging lens 613. By making the distance between the collimator lens 612 and the light-shielding aperture 614 equal to the focal length f1 of the collimator lens 612 and the distance between the converging lens 613 and the light-shielding aperture 614 equal to the focal length f2 of the converging lens 613, such a configuration can be realized.

[0060] The light-shielding aperture 614 shields the central portion of the optical path of the collimated light including the optical axis of the illumination optical system 610. By shielding this portion, it is possible to realize illumination light L and L' that obliquely enters the liquid column C as shown in Fig. 4(a) and does not directly enter the camera 72. That is, the light-shielding aperture 614 has a function of shielding, at any position on its optical path, the light that travels from the point light source 611 and is directed toward the camera 72 via the illumination optical system 610.

[0061] In this sense, the arrangement position of the light-shielding aperture 614 is not limited to that shown in Fig. 5(a). For example, even if a light-shielding member corresponding to the light-shielding aperture 614 is disposed between the point light source 611 and the collimator lens 612 or between the converging lens 613 and the liquid column C, it is possible to obtain a similar effect. However, the preferable illumination conditions described below are established when the light-shielding aperture 614 is disposed on the optical path of the collimated light as shown in Fig. 5(a).

[0062] Next, in the auxiliary illumination unit 6a configured as described above, the conditions for the light emitted from the point light source 611 not to directly enter the camera 72 and for the reflected light and refracted light by the liquid column C to enter the camera 72 will be described. Here, the camera 72 is assumed to have an imaging lens 721, a light receiving element 722, and a diaphragm 723 following the configuration of a general imaging device. Note that here the imaging lens 721 is described as a single lens, but it may be configured as an imaging optical system composed of a plurality of optical elements.

[0063] The light-receiving element 722 is a two-dimensional image sensor such as a CCD imaging device or a CMOS sensor, and is arranged at a position corresponding to the focal length f3 with respect to the imaging lens 721. Light emitted from the object to be imaged and incident on the imaging lens 721 forms an image on the light-receiving element 722, thereby imaging the image of the object to be imaged. The aperture stop 723 defines the observation pupil.

[0064] For the following description, the radius of the observation pupil defined by the aperture stop 723 is represented by the symbol a. Also, the distance between the position P of the liquid column and the imaging lens 721, that is, the working distance, is represented by the symbol d. Further, the viewing angle looking at the observation pupil from the position P of the liquid column is represented by the symbol θ.

[0065] On the other hand, the following definitions are also made for the illumination optical system side. That is, the working distance between the converging lens 613 and the position P of the liquid column is represented by the symbol d'. In this example, the working distance d' is equal to the focal length f2 of the converging lens 613. Also, the radius of the light-shielding portion of the light-shielding stop 614 is represented by the symbol a'. Further, the maximum value of the incident angle of the light incident on the position P of the liquid column from the converging lens 613 is represented by the symbol φ1, and the minimum value is represented by the symbol φ2.

[0066] From FIG. 5(a), the following equation: a = d·tanθ … (Equation 1) is established. Also, the radius a' of the light-shielding portion necessary to shield the light directly incident on the observation pupil passing through the position P of the liquid column is given by the following equation: a' ≧ (a·d') / d … (Equation 2) is represented. By setting the arrangement such that these (Equation 1) and (Equation 2) are simultaneously satisfied, the desired illumination conditions are realized.

[0067] When liquid is ejected from the nozzle and a liquid column C is formed at position P, as shown in Fig. 5(b), light whose path is changed by reflection on the surface of the liquid column C or refraction inside it enters the camera 72. More specifically, among the light whose path has changed, the light that has passed through the aperture stop 723 enters the imaging lens 721 via the aperture stop 723. As a result, an image of the liquid column C is formed on the imaging surface of the light receiving element 722, and thus the liquid column C is imaged. If the liquid column C is transparent, the light enters the imaging lens 721 with little attenuation in the liquid. Therefore, a bright image of the liquid column C can be obtained.

[0068] The light incident on the liquid column C can be reflected and refracted in various directions, but by making the illumination light incident at as wide an angle as possible, the probability of the reflected and refracted light entering the imaging lens 721 can be improved. This contributes to improving the brightness of the image of the liquid column C in the image and its signal-to-noise ratio. For this purpose, it is preferable that the numerical aperture of the illumination optical system as seen from the position P of the liquid column is as large as possible. Specifically, it is preferable that the maximum incident angle φ1 of the illumination lights L and L' with respect to the position P of the liquid column is as large as possible, while the minimum incident angle φ2 is as small as possible as long as the direct light does not enter the imaging lens 721.

[0069] Fig. 5(c) is a diagram showing an example of the aperture shape of the light shielding stop 614. In the figure, the hatched portion represents the light shielding part, and the plain portion represents the transmission part. When the shape of the light shielding part 614a of the light shielding stop 614 is circular with the optical axis AX of the illumination optical system 610 as the center as shown in the left figure of Fig. 5(c), the ray diagram seen from the side is also the same as that in Fig. 6(a). Here, as shown in Fig. 4(b), the camera 72 is arranged with its optical axis tilted so as to overlook the substrate S. As long as the illumination light passing through the position P of the liquid column does not directly enter this camera 72, the illumination light may be emitted upward and downward. Therefore, it is possible to use the light shielding stop 614 having such a shape.

[0070] On the other hand, if the center width of the light-shielding portion is kept unchanged and it is elongated vertically, the upward and downward light emission can be suppressed, so that it is possible to more effectively avoid direct light from entering the camera 72 arranged in a bird's-eye view. For example, as shown in the right figure of Fig. 5(c), when a light-shielding portion 614b with a constant width extending vertically is provided so as to divide the light-transmitting portion left and right, the effect of suppressing the spread of light in the vertical direction and preventing direct light from entering the camera 72 becomes greater.

[0071] Fig. 6 is a diagram showing an example of a configuration closer to an actual machine. As shown in Fig. 3(a) and Fig. 6(a), in the actual machine, the auxiliary illumination unit 6a is at a relatively close position when viewed from the position P of the liquid column, while the camera 72 is at a farther position. Typically, for example, the focal lengths f1 and f2 (= d') of the lenses 612 and 613 constituting the auxiliary illumination unit 6a are both about 20 mm. On the other hand, for example, when the diameter of the substrate S is 300 mm, the working distance d from the position P of the liquid column to the camera 72 is about 350 mm. Also, the diameter 2a of the observation pupil is about 40 mm.

[0072] Therefore, the radius a' of the light-shielding portion of the light-shielding aperture 614 can be made smaller than that in the principle diagram shown in Fig. 5(a). For example, when the lens diameter is about 20 mm with the above-mentioned dimensional relationship, the radius a' of the light-shielding portion can be about 2.4 mm. At this time, the maximum incident angle φ1 of the illumination light L and L' viewed from the position P is about 45 degrees, and the minimum incident angle φ2 is about 6.8 degrees.

[0073] Figs. 6(b) and 6(c) are plan views showing configuration examples of the auxiliary illumination unit 6a corresponding to a plurality of nozzles, and among them, Fig. 6(b) is a ray diagram when there is no liquid column. Fig. 6(c) is a ray diagram in a state where liquid is discharged from each of the three nozzles 53 to 55 and three liquid columns C1 to C3 are formed.

[0074] As shown in Fig. 3(b), let the positions where liquid columns are formed by the liquids ejected from the three nozzles 53, 54, and 55 be positions P1, P2, and P3, respectively. For each of these positions P1 to P3, a set of a light source 611 and an illumination optical system 610 is provided. These configurations are basically the same as those shown in Fig. 6(a).

[0075] However, in order to prevent the light emitted from any of the illumination optical systems 610 from entering the imaging lens 721, as can be seen from Fig. 6(b), the minimum incident angle φ2 of the illumination lights L and L' viewed from each of the positions P1 to P3 needs to be larger than the above, and for this purpose, the light-shielding portion radius a' (if the lens diameters are the same) must be made larger than the above numerical example. Generally, in the auxiliary illumination unit 6a, it is necessary to make the lens diameter smaller than the above example, and accordingly, the numerical values of the minimum incident angle φ2 and the light-shielding portion radius a' also become smaller. For example, when the optical axis distance D between the condenser lenses 613 in the auxiliary illumination unit 6a is 12.5 mm, the diameter 2a of the observation pupil is 30 mm, the working distance d is 350 mm, and the focal length f2 of the condenser lens 613 is 20 mm, from the relationship shown in Fig. 6(b), the following formula derived: a' ≥ f2·tanφ2, tanφ2 = (a + D) / d … (Equation 3) Thus, the minimum incident angle φ2 is about 4.49 degrees, and the light-shielding portion radius a' is about 1.57 mm or more.

[0076] Also, in order to prevent the light from one point light source 611 from entering other illumination optical systems 610, a light-shielding member 615 is arranged between adjacent illumination optical systems 610. Also, the arrangement pitch between the nozzles 53 to 55 is, for example, about 12.5 mm. In order to configure the auxiliary illumination unit 6a to be small while arranging the three sets of illumination optical systems 610 with such a small pitch, as the collimator lens 612 and the condenser lens 613, for example, cylindrical lenses can be applied.

[0077] By using the auxiliary illumination unit 6a configured as described above, it becomes possible to image the images of the three liquid columns C1 to C3 formed in the liquid discharged from each of the three nozzles 53 to 55 independently and with sufficient brightness.

[0078] As described above, the configuration example of the first aspect of the auxiliary illumination unit 6 in which the illumination lights L and L' are convergent lights has been described. Hereinafter, as shown in FIG. 4(b), a configuration example of the second aspect of the auxiliary illumination unit 6 using parallel lights as the illumination lights L and L' will be described.

[0079] FIG. 7 is a plan view showing a configuration example for realizing the liquid column illumination of the second aspect. First, the case where there is only one liquid column will be described with reference to FIGS. 7(a) and 7(b). In this case, the auxiliary illumination unit 6b can be provided with a point light source 621 and a collimator lens 622 as shown in FIG. 7(b). By arranging the point light source 621 at the focal position of the collimator lens 622 having a focal length f4, the light emitted through the collimator lens 622 can be made parallel light.

[0080] The illumination light L, which is parallel light emitted from the auxiliary illumination unit 6b as parallel light, has a width W of the light beam in a plan view larger than the width of the liquid column C and passes through both side portions of the liquid column C. A light shielding diaphragm 624 may be further provided to adjust the width W of the light beam to an appropriate value. Both the optical axis of the collimator lens 622 indicated by the two-dot chain line and the imaging axis of the camera 72 indicated by the one-dot chain line pass through the center of the liquid column C, but are non-parallel to each other. The angle α at which the two axes intersect can be, for example, any angle greater than 0 degrees and equal to or less than 75 degrees.

[0081] Here, the condition for the direct light from the auxiliary illumination unit 6b not to be incident on the camera 72 and for the refracted light by the liquid column C to be received by the camera 72 is that the distance Dy between the optical axis of the illumination light L and the imaging axis at the observation pupil position of the camera 72 is smaller than the half width (W / 2) on the component side of the illumination light L. By doing so, as shown in Fig. 7(b), it is possible to realize an illumination condition in which the illumination light L is not directly incident on the imaging lens 721 and, when there is a liquid column C, the refracted light thereof is incident on the imaging lens 721.

[0082] On the other hand, the condition for the reflected light L1 on the liquid column surface to be incident on the camera 72 can be expressed by the following equation from the relationship shown in Fig. 7(a) and the law of reflection: δ = γ / 2 + 90° … (Equation 4) Here, the angle γ is the angle formed by the traveling direction of the light reflected on the surface of the liquid column C with respect to the traveling direction of the illumination light L, and the angle δ is the angle formed by the normal line of the reflecting surface with respect to the traveling direction of the illumination light L.

[0083] When the working distance d is sufficiently large with respect to the diameter of the liquid column C, it can be substantially regarded that α ≒ γ, so that both the refracted light inside the liquid column C and the reflected light on the surface of the liquid column C are incident on the camera 72. As a result, similar to the first aspect described above, it is possible to improve the S / N ratio in imaging the liquid column C.

[0084] The correspondence to the plurality of nozzles in the second aspect is simpler than that in the first aspect. That is, the light beam width W of the parallel light may be set so as to illuminate the plurality of liquid columns formed by each nozzle collectively. In this case, as shown in Fig. 7(c), the arrangement may be such that the direction of the arrangement of the liquid columns C1 to C3 indicated by the dotted line is orthogonal to the traveling direction of the illumination light L indicated by the two-dot chain line, and the imaging axis indicated by the one-dot chain line is inclined with respect to these, or as shown in Fig. 7(d), the arrangement may be such that the direction of the arrangement of the liquid columns C1 to C3 is orthogonal to the imaging axis, and the traveling direction of the illumination light L is inclined with respect to these.

[0085] In any case, by ensuring that the illumination light L does not directly enter the camera 72 and that the reflected light and refracted light enter the camera 72 when the liquid columns C1 to C3 are present, it becomes possible to image each of the liquid columns C1 to C3 individually with an excellent signal-to-noise ratio. Even when parallel light is used as the illumination light in this way, as shown in Fig. 4(b), the illumination lights L and L' can be configured to enter the liquid column from two directions symmetric with respect to the imaging axis. However, since the entire liquid column is included in the optical path of the illumination light L and the inclination between the traveling direction of the illumination light L and the imaging axis of the camera 72 is not so large, the effect of doing so is considered not to be as great as in the first aspect.

[0086] For example, when the arrangement pitch of the nozzles 53 to 55 (i.e., the arrangement pitch of the liquid columns C1 to C3) is about 12.5 mm and the working distance d is about 350 mm, by setting the light beam width W of the illumination light L to 40 mm and the inclination α between the traveling direction of the illumination light L and the imaging axis to about 10 degrees, it is possible to clearly image the images of the three liquid columns C1 to C3 with the camera 72.

[0087] As described above, the substrate processing apparatus 1 of this embodiment corresponds to an embodiment of the "substrate processing apparatus" according to the present invention. In this embodiment, among the illumination unit 71 and the auxiliary illumination unit 6, the auxiliary illumination unit 6 functions as the "illumination unit" of the present invention. Further, in the above embodiment, the nozzles 53, 54, and 55 function as the "nozzles" of the present invention, and the camera 72 functions as the "light receiving unit" and the "imaging device" of the present invention.

[0088] Also, among the auxiliary illumination unit 6a, the point light source 611 corresponds to the "light source" of the present invention, the collimator lens 612 and the converging lens 613 correspond to the "lenses" of the present invention, and the light shielding diaphragm 614 corresponds to the "light shielding diaphragm" of the present invention, respectively. Further, when the control unit 80 determines the liquid discharge state from the nozzle based on the image of the imaged liquid column, the control unit 80 functions as the "determination unit" of the present invention.

[0089] Note that the present invention is not limited to the above-described embodiments, and various modifications can be made other than those described above without departing from the spirit of the invention. For example, in the embodiment, a camera 72 having an imaging function is used as the "light receiving unit" of the present invention, and the state of each part is monitored by imaging a region including the liquid column formation position P. This camera 72 monitors the state of the substrate S and a plurality of nozzles in addition to the nozzles 53 to 55. However, for the purpose of imaging specific nozzles, for example, the nozzles 53 to 55 and the liquid discharged from them, a camera separate from the camera that images the entire substrate S may be used.

[0090] And when a dedicated camera is used only for imaging the liquid column, the illumination unit 71 for irradiating illumination light from the camera side is not necessarily required, and it is possible to image a bright image of the liquid column only with the auxiliary illumination unit 6.

[0091] Also, for the purpose of simply determining the liquid discharge state, the "light receiving unit" of the present invention does not necessarily have to have an imaging function. For example, a photosensor that outputs a signal having a magnitude corresponding to the amount of received light may be used. In this embodiment, since the configuration is such that the reflected light and refracted light of the illumination light that occur only when the liquid column is formed are received, the difference in the amount of light due to the presence or absence of the liquid column is significant. Therefore, it is possible to detect the presence or absence and the size of the liquid column based on the magnitude of the amount of received light from the region including the position where the liquid column is formed, and for this purpose, an imaging function is not necessarily required.

[0092] In addition, the auxiliary illumination unit 6 of the above-described embodiment is configured to make illumination light enter the liquid column formed between the nozzle and the substrate substantially in the horizontal direction. However, in this case, there is a possibility that the processing liquid splashed from the peripheral portion of the substrate may adhere to the auxiliary illumination unit 6. Then, for example, the liquid adhering to the optical window that emits the illumination light may change the emission direction of the illumination light. As a means to avoid this, for example, there is a method of subjecting the surface of the optical window to hydrophilic treatment so that the adhered liquid does not form water droplets. Further, by changing the arrangement of the auxiliary illumination unit so that the illumination light is irradiated from an obliquely upward direction, it becomes possible to cause the liquid splashed from the substrate to fall downward without adhering to the optical window.

[0093] In addition, the auxiliary illumination unit 6 of the above-described embodiment is integrally attached to the nozzles 53 to 55 on the rotating arm 52. As a result, an effect can be obtained in which the positional relationship between the auxiliary illumination unit 6 and the nozzles 53 to 55 can always be kept constant regardless of the position of the arm 52. However, the "processing position" with respect to the substrate S when each of the nozzles 53 to 55 discharges liquid is predetermined, and the imaging of the liquid column C only needs to be performed when the nozzles 53 to 55 are in the processing position. Therefore, the auxiliary illumination unit does not necessarily need to be attached to the arm 52. For example, the auxiliary illumination unit may be provided at a position facing the nozzles 53 to 55 when the nozzles 53 to 55 are positioned at the processing position on the inner surface of the splash guard 20.

[0094] In this embodiment, the position of the camera 72 is fixed. However, for example, as described in Patent Document 1, it is also possible to combine the auxiliary illumination unit according to this embodiment with a configuration in which the camera moves to the imaging position as needed to image the liquid column.

[0095] In the above-described embodiment, the present invention is applied to monitoring the discharge state in so-called bevel processing in which liquid is supplied to the peripheral portion of the substrate S and the portion is processed. However, the present invention is not limited to such bevel processing, and can be applied to various processes in which liquid is discharged from nozzles disposed opposite to each other on the substrate. However, it is a requirement for achieving sufficient effects that the relative positional relationship among the nozzle, the illumination unit, and the light receiving unit does not change during the process.

[0096] In addition, the dimensional examples of the above-described respective parts are shown as reference values, and these dimensions can be appropriately modified as long as they do not contravene the technical idea of the present invention.

[0097] As described above by way of example of specific embodiments, in the substrate processing apparatus according to the present invention, for example, the illumination unit can include a light source, a lens that converges the light emitted from the light source to a liquid column, and a light shielding diaphragm that partially shields the light traveling toward the light receiving unit on the optical path between the light source and the convergence point of the convergent light. Here, the light shielding diaphragm may be provided, for example, at a position that shields the light on the optical axis of the lens.

[0098] According to such a configuration, among the light converged toward the liquid column by the lens, by shielding the component that attempts to travel toward the light receiving unit, the illumination conditions in line with the object of the present invention can be realized. Specifically, the convergent light that does not enter the light receiving unit when the liquid column does not exist can be irradiated toward the position where the liquid column is formed.

[0099] Also, for example, the light flux of the illumination light may have a shape symmetric with respect to the vertical plane including the center of the liquid column and the center of the light receiving unit. According to such a configuration, when viewed from the light receiving unit side, both side surfaces of the liquid column are illuminated under the same illumination conditions. Therefore, for example, it becomes possible to accurately calculate the width of the liquid column and the like from the light receiving result.

[0100] For example, the light receiving unit may have an imaging device that includes, in the imaging field of view, the space in which the liquid column is formed between the nozzle and the substrate. According to such a configuration, the liquid column can be detected as its image, and moreover, sufficient brightness can be ensured. Therefore, it is possible to obtain more detailed information such as the presence or absence of the liquid column, the liquid volume, and the flow-down state from the image.

[0101] Further, the substrate processing apparatus according to the present invention may have a plurality of nozzles arranged at a predetermined distance from each other. The illumination for the liquid column according to the present invention can also be suitably applied to a configuration having such a plurality of nozzles.

[0102] For example, visible light can be used as the illumination light. When the liquid discharged from the nozzle is transparent, that is, exhibits high transmittance to visible light, it may not be possible to obtain a high S / N ratio with a configuration that detects the liquid column depending only on the reflected light as in the prior art. In the present invention, since it is possible to detect not only the reflected light but also the refracted light passing through the liquid column, it is possible to ensure a good S / N ratio even with visible light.

[0103] For example, the processing position may be a position where the nozzle is above the peripheral edge of the substrate, and the liquid discharged from the nozzle may be supplied to the peripheral edge. In such a configuration, the distance between the nozzle and the substrate is small, and generally, the amount of liquid supplied to the substrate is also small. For this reason, the liquid column formed by the discharged liquid is minute and its detection tends to be difficult. By applying the present invention, it becomes possible to detect the liquid column with a good S / N ratio even in such a case.

[0104] For example, a determination unit that determines the discharge state of the liquid from the nozzle based on the light receiving result of the light receiving unit may be provided. In the present invention, it is possible to optically detect the liquid column formed by the liquid discharged from the nozzle with a good S / N ratio. Therefore, it is possible to reduce the erroneous determination of the discharge state.

Industrial Applicability

[0105] This invention is applicable to the entire technology of processing a substrate by discharging a liquid from a nozzle disposed opposite to the upper surface of the substrate. In particular, the present invention functions effectively in a case where there is a need to optically detect a transparent liquid discharged from the nozzle.

Explanation of Signs

[0106] 1 Substrate processing apparatus 6, 6a, 6b Auxiliary illumination unit (illumination unit) 10 Substrate holding unit 11 Spin base 50 Fluid supply unit 52 Arm 53, 54, 55 Nozzle 72 Camera (light receiving unit, imaging device) 80 Control unit (judgment unit) 611 Point light source (light source) 612 Collimator lens (lens) 613 Converging lens (lens) 614 Light-shielding diaphragm S Substrate

Claims

1. a substrate holding unit that holds a substrate substantially horizontally; a nozzle disposed at a processing position facing the upper surface of the substrate held by the substrate holding unit and discharging liquid in a columnar shape toward the substrate; an illumination unit that emits illumination light toward a liquid column formed between the nozzle and the substrate by the liquid; a light receiving unit provided on the opposite side of the illumination unit across the nozzle at the processing position and receiving light from the liquid column; comprising; the illumination unit emits, as the illumination light, converged light converged so that a convergence point is included in the liquid column; the light receiving unit is provided at a position where a light beam of the illumination light emitted from the illumination unit and passing through the position where the liquid column is formed does not enter, a substrate processing apparatus.

2. a substrate holding unit that holds a substrate substantially horizontally; a nozzle disposed at a processing position facing the upper surface of the substrate held by the substrate holding unit and discharging liquid in a columnar shape toward the substrate; an illumination unit that emits illumination light toward a liquid column formed between the nozzle and the substrate by the liquid; a light receiving unit provided on the opposite side of the illumination unit across the nozzle and receiving light from the liquid column; comprising; the illumination unit emits, as the illumination light, parallel light having a beam width larger than the width of the liquid column in a width direction perpendicular to the incident direction of the illumination light, and the light beam of the illumination light has a shape symmetric with respect to a vertical plane including the center of the liquid column and the center of the light receiving unit; the light receiving unit is provided at a position where a light beam of the illumination light emitted from the illumination unit and passing through the position where the liquid column is formed does not enter, a substrate processing apparatus.

3. the illumination unit includes a light source, a lens that converges light emitted from the light source onto the liquid column, and a light shielding diaphragm that partially shields light traveling on the optical path from the light source to the convergence point of the converged light toward the light receiving unit, the substrate processing apparatus according to claim 1.

4. the light shielding diaphragm is provided at a position that shields light on the optical axis of the lens, the substrate processing apparatus according to claim 3.

5. the light beam of the illumination light has a shape symmetric with respect to a vertical plane including the center of the liquid column and the center of the light receiving unit, the substrate processing apparatus according to any one of claims 1, 3, and 4.

6. the light receiving unit includes an imaging device that includes a space where the liquid column is formed between the nozzle and the substrate in an imaging field of view, the substrate processing apparatus according to any one of claims 1 to 5.

7. The substrate processing apparatus according to any one of claims 1 to 6, having a plurality of the nozzles arranged at a predetermined distance from each other.

8. The substrate processing apparatus according to any one of claims 1 to 7, wherein the illumination light is visible light.

9. The substrate processing apparatus according to any one of claims 1 to 8, wherein the processing position is a position where the nozzle is above a peripheral portion of the substrate, and a liquid discharged from the nozzle is supplied to the peripheral portion.

10. The substrate processing apparatus according to any one of claims 1 to 9, further comprising a determination unit configured to determine a discharge state of the liquid from the nozzle based on a light reception result of the light reception unit.

11. A step of discharging a liquid columnar from a nozzle disposed at a processing position facing an upper surface of a substrate held substantially horizontally toward the substrate; A step of emitting illumination light from an illumination unit toward a liquid column formed between the nozzle and the substrate by the liquid, and receiving light from the liquid column by a light reception unit provided on the side opposite to the illumination unit with the nozzle at the processing position interposed therebetween; Comprising: The illumination unit emits, as the illumination light, convergent light converged so that a convergence point is included in the liquid column, or parallel light having a beam width larger than the width of the liquid column in a width direction perpendicular to an incident direction of the illumination light, and a shape of a light flux of the parallel light is symmetric with respect to a vertical plane including the center of the liquid column and the center of the light reception unit; The light reception unit is provided at a position where a light flux of the illumination light emitted from the illumination unit and passing through a position where the liquid column is formed does not enter, a substrate processing method.

Images