Flow cell and substrate processing apparatus

Abstract

To provide a device capable of more accurately detecting particles or bubbles in a processing liquid.SOLUTION: The flow cell 44 includes a plurality of branch flow paths 400 connected to a supply port to which a fluid (processing liquid) is supplied, a light source, a plurality of light receiving elements, and a control unit. Each of the plurality of light receiving elements corresponds to one of the plurality of branch flow paths 440, receives scattered light or diffracted light generated when light from the light source hits particles or bubbles contained in the processing liquid passing through the corresponding branch flow path 440, or interference light generated by interference between the scattered light and the reference light, and outputs a signal corresponding to the received scattered light, diffracted light, or interference light. The controller calculates the number or size of particles or air bubbles contained in the processing liquid based on the signal output from the light receiving element. In addition, the flow velocity of the fluid (processing liquid) decreases when the fluid advances from the supply pipe 43 to the branch flow path 404.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a flow cell having a plurality of branched flow paths, and a substrate processing apparatus having the flow cell and processing a substrate using a processing liquid. [Background technology]

[0002] Conventionally, semiconductor wafer manufacturing processes use substrate processing apparatuses that process substrates using processing liquids such as chemicals. The substrate processing apparatus holds a substrate inside a chamber and supplies the processing liquid to the substrate. A nozzle that ejects the processing liquid toward the substrate is connected to a processing liquid supply source via piping or the like. The piping may also be provided with a particle counter for detecting particles and bubbles in the processing liquid that may degrade the quality of substrate processing. The configuration of the particle counter is described, for example, in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-158478 Summary of the Invention [Problem to be solved by the invention]

[0004] The particle counter of Patent Document 1 comprises a light source (1), a flow cell (2), a detection unit (4), and a counting unit (6) (paragraph 0013). The flow cell (2) is a transparent tubular member bent into an L-shape, and forms a flow path (2a) for a fluid containing particles to be counted (paragraphs 0015, 0016, Figure 2). Laser light emitted from the light source (1) is split into measurement light and reference light by a beam splitter (11). The reference light is attenuated by an attenuator (14), passes through a mirror (15) and a beam expander (16), and then enters a beam splitter (17) as a substantially parallel beam (paragraph 0066).

[0005] On the other hand, the measurement light is incident on the detection region in the flow cell (2) by the irradiation optical system (12) via the optical path length variable unit (31). When a particle passes through the detection region in the flow cell (2), scattered light is generated from the particle. The scattered light is incident on the beam splitter (17) as approximately parallel light by the detection optical system (13) (paragraph 0067). That is, the above-mentioned reference light and the scattered light from the particle are incident on the beam splitter (17). Then, the interference light of the two beams is emitted from the beam splitter (17) (paragraph 0068).

[0006] The detector (4) receives the interference light with the light-receiving elements (21a, 21b), amplifies the electrical signals output from the light-receiving elements (21a, 21b) with the amplifiers (22a, 22b), and generates a detection signal (Vo) corresponding to the difference between the signals (paragraphs 0042, 0043). The counter (6) counts the particles based on the detection signal (Vo) (paragraph 0056).

[0007] However, in the particle counter of Patent Document 1, the velocity of the particles to be counted does not decrease as they pass through the detection area in the flow cell (2). Furthermore, the particle detection area occupies a very small proportion of the flow cell (2) (FIG. 3), making it difficult to accurately detect all particles passing through the flow cell (2). Therefore, there is room for improvement in the configuration of the flow cell (2) and the particle counter in order to count particles more accurately.

[0008] The present invention has been made in view of the above circumstances, and has as its object to provide a technique for detecting particles or bubbles in a processing liquid with higher accuracy. [Means for solving the problem]

[0009] To solve the above problems, a first invention of the present application provides a flow cell comprising a plurality of branched flow paths, a light source, a plurality of light-receiving elements, and a control unit. The plurality of branched flow paths are connected to a supply port through which a fluid is supplied. The light source irradiates the plurality of branched flow paths with light. The plurality of light-receiving elements are arranged on the opposite side of the light source relative to each of the plurality of branched flow paths. The control unit calculates the number or size of particles or bubbles contained in the fluid based on a signal output from the light-receiving element. Each of the plurality of branched flow paths is capable of passing the particles or the bubbles. Furthermore, each of the plurality of light-receiving elements corresponds to one of the plurality of branched flow paths and is capable of receiving scattered light or diffracted light generated when light from the light source strikes the particles or the bubbles contained in the fluid passing through the corresponding branched flow path, or interference light generated when the scattered light interferes with a reference light, and outputting the signal corresponding to the received scattered light, diffracted light, or interference light.

[0010] A second aspect of the present invention is the flow cell of the first aspect, further comprising a camera for capturing images of the branched flow paths, the camera having a plurality of light-receiving elements capable of receiving the scattered light, the diffracted light, or the interference light and outputting the signals, respectively.

[0011] A third aspect of the present invention is the flow cell of the first aspect, wherein each of the plurality of light-receiving elements is capable of outputting a signal corresponding to the intensity of the received scattered light, diffracted light, or interference light, and the control unit calculates the number or size of the particles or bubbles contained in the fluid based on the change in intensity of the signal output from the light-receiving elements.

[0012] The fourth invention of the present application is a flow cell according to any one of the first to third inventions, further comprising an abnormality alarm unit that outputs an abnormality signal when the result of calculation by the control unit of the number or size of the particles or bubbles exceeds a predetermined value.

[0013] A fifth aspect of the present invention is a substrate processing apparatus for processing a substrate using the processing liquid as the fluid, comprising a nozzle, a supply source, a supply pipe, and the flow cell of any one of the first to fourth aspects. The nozzle ejects the processing liquid onto the substrate. The supply source stores the processing liquid to be supplied to the nozzle. The supply pipe connects the supply source to the nozzle. The supply port is an opening of the supply pipe. Furthermore, the flow velocity of the processing liquid decreases as it travels from the supply pipe through the supply port to the branch flow path.

[0014] A sixth aspect of the present invention is the substrate processing apparatus of the fifth aspect, wherein a total value of the cross-sectional areas of the branched flow paths is greater than a cross-sectional area of ​​the supply pipe upstream of the branched flow paths.

[0015] A seventh aspect of the present invention is the substrate processing apparatus of the fifth or sixth aspect, wherein the supply pipe has an upstream pipe located upstream of the flow cell and a downstream pipe located downstream of the flow cell. An upstream end of each of the branched flow paths is continuous with a downstream end of the upstream pipe. A downstream end of each of the branched flow paths is continuous with an upstream end of the downstream pipe. [Effects of the Invention]

[0016] According to the first to seventh inventions of the present application, by using multiple light receiving elements to detect scattered light, diffracted light, or interference light generated in all branched flow paths, particles or bubbles in the entire processing liquid (fluid) can be detected with high accuracy.

[0017] In particular, according to the fourth aspect of the present invention, when the number or size of particles or bubbles exceeds an allowable range, an abnormality signal can be output.

[0018] In particular, according to the fifth invention of the present application, the flow rate of the processing liquid (fluid) containing particles or bubbles is reduced in each branch flow path, and the particles or bubbles are allowed to advance in very small amounts in each branch flow path, thereby enabling the number and size of particles and bubbles to be detected more accurately.

[0019] In particular, according to the sixth aspect of the present invention, the flow velocity of the processing liquid containing particles or bubbles in each branch flow path can be reduced with a simple structure.

[0020] In particular, according to the seventh invention of the present application, by providing a flow cell inline in the supply piping, particles or bubbles in the processing liquid can be detected in the flow cell, and the processing liquid can be allowed to proceed downstream as is and used in subsequent processes. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a diagram schematically illustrating a configuration of a substrate processing apparatus. [Figure 2] FIG. 2 is a diagram schematically illustrating the configuration of a processing liquid supply unit and a particle counter. [Figure 3] FIG. 2 is a diagram schematically illustrating a configuration of a part of a processing liquid supply unit and a particle counter. [Figure 4] FIG. 4 is a vertical cross-sectional view taken along the line AA in FIG. 3. [Figure 5] FIG. 5 is a cross-sectional view taken from the position BB in FIG. 4. [Figure 6] 10 is a graph showing an example of a signal output from a light receiving element. [Figure 7] FIG. 2 is a control block diagram of the substrate processing apparatus. [Figure 8] FIG. 10 is a diagram schematically illustrating the configuration of a flow cell and a particle counter according to a first modified example. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the components described in these embodiments are merely examples and are not intended to limit the scope of the present invention. Furthermore, in the drawings, the dimensions and numbers of each part may be exaggerated or simplified as necessary to facilitate understanding.

[0023] <1. Configuration of the substrate processing apparatus> FIG. 1 is a schematic diagram illustrating the configuration of a substrate processing apparatus 1 according to one embodiment of the present invention. The substrate processing apparatus 1 is an apparatus for cleaning the surface of a substrate W by supplying a processing liquid, which is a fluid, to the surface of the substrate W during a semiconductor wafer manufacturing process. That is, the substrate processing apparatus 1 processes the substrate W using the processing liquid. The substrate W may be, for example, a semiconductor substrate (silicon wafer) having a disk shape. However, the substrate W may also be 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, or a substrate for a magneto-optical disk. The shape of the substrate W may be other than a disk shape, such as a rectangular plate shape.

[0024] As shown in FIG. 1, the substrate processing apparatus 1 includes a chamber 10, a substrate holding unit 20, a rotation mechanism 30, a processing liquid supply unit 40, a particle counter 50 (see FIGS. 2 and 3 described below), a cup 60, a control unit 70, and a display unit 80.

[0025] The chamber 10 is a housing that forms a processing space 11 for processing a substrate W. The chamber 10 has sidewalls 12 that surround the sides of the processing space 11, a top plate 13 that covers an upper portion of the processing space 11, and a bottom plate 14 that covers a lower portion of the processing space 11. A substrate holder 20, a rotation mechanism 30, a processing liquid supply unit 40, and a cup 60 are housed inside the chamber 10.

[0026] A portion of the side wall 12 is provided with a loading / unloading port 15 for loading / unloading the substrate W into / from the chamber 10, and a shutter (not shown) for opening / closing the loading / unloading port 15.

[0027] The substrate holding unit 20 is a mechanism that holds the substrate W in a horizontal position (a position in which the normal is oriented vertically) inside the chamber 10. As shown in FIG. 1, the substrate holding unit 20 has a disk-shaped spin base 21 and a plurality of chuck pins 22. The plurality of chuck pins 22 are provided at equal angular intervals on the outer periphery of the upper surface of the spin base 21. The substrate W is held by the plurality of chuck pins 22 with the surface to be processed onto which the processing liquid is discharged facing upward. Each chuck pin 22 contacts the lower surface and outer peripheral edge surface of the peripheral edge of the substrate W, and supports the substrate W at a position above the upper surface of the spin base 21 with a small gap therebetween.

[0028] A chuck pin switching mechanism 23 is provided inside the spin base 21 for switching the positions of the plurality of chuck pins 22. The chuck pin switching mechanism 23 switches the plurality of chuck pins 22 between a holding position where the chuck pins 22 hold the substrate W and a release position where the chuck pins 22 release the substrate W from the holding position.

[0029] The rotation mechanism 30 is a mechanism for rotating the substrate holding part 20. The rotation mechanism 30 is housed inside a motor cover 31 provided below the spin base 21. As indicated by the dashed line in FIG. 1 , the rotation mechanism 30 has a motor 32 and a support shaft 33. The support shaft 33 extends vertically, with its lower end connected to the motor 32 and its upper end fixed to the center of the lower surface of the spin base 21. When the motor 32 is driven, the support shaft 33 rotates about its axis 330. Then, together with the support shaft 33, the substrate holding part 20 and the substrate W held by the substrate holding part 20 also rotate about the axis 330.

[0030] The cup 60 is a mechanism for collecting the processing liquid after use. As shown in FIG. 1, the cup 60 has an annular guide plate 61 that surrounds the substrate holding part 20. The cup 60 can be raised and lowered by a lifting mechanism (not shown). When the nozzle 41 (described later) ejects the processing liquid, the guide plate 61 surrounds the substrate W held by the substrate holding part 20. The processing liquid ejected from the nozzle 41 is supplied to the upper surface of the substrate W, and then scattered outward by centrifugal force caused by the rotation of the substrate W. The processing liquid scattered from the substrate W is then collected by the guide plate 61. The processing liquid collected by the guide plate 61 is discharged to the outside of the chamber 10 through piping (not shown).

[0031] The processing liquid supply unit 40 is a mechanism that supplies a processing liquid toward the upper surface of the substrate W held by the substrate holder 20. Fig. 2 is a diagram schematically showing the configuration of the processing liquid supply unit 40 and the particle counter 50. As shown in Figs. 1 and 2, the processing liquid supply unit 40 has a nozzle 41, a supply source 42, supply piping 43, a flow cell 44, a pump 45, and a valve 46.

[0032] The nozzle 41 ejects a processing liquid toward the upper surface of the substrate W held by the substrate holding unit 20. As shown in FIG. 1, the nozzle 41 has a nozzle arm 411 and a nozzle head 412 provided at the tip of the nozzle arm 411. The nozzle arm 411 rotates in the horizontal direction by driving a motor (not shown). This allows the nozzle head 412 to move between a processing position (position in FIG. 1) above the substrate W held by the substrate holding unit 20 and a retracted position outside the cup 60.

[0033] The nozzle head 412 is connected to a supply source 42 via a supply pipe 43. The supply source 42 stores the processing liquid to be supplied to the nozzle 41. The supply pipe 43 connects the supply source 42 and the nozzle 41. A pump 45 and a valve 46 are provided on the path of the supply pipe 43. When the valve 46 is opened and the pump 45 is operated with the nozzle head 412 placed at the processing position, the processing liquid is supplied from the supply source 42 through the supply pipe 43 to the nozzle head 412. Then, the processing liquid is discharged from the nozzle head 412 toward the upper surface of the substrate W.

[0034] In the substrate processing apparatus 1, while the substrate W is rotated by the rotation mechanism 30, the nozzle head 412 ejects the processing liquid onto the center of the upper surface of the substrate W. The processing liquid spreads from the center to the periphery of the upper surface of the substrate W due to centrifugal force caused by the rotation of the substrate W. As a result, a liquid film of the processing liquid is formed on the upper surface of the substrate W.

[0035] The processing liquid may be, for example, a DHF cleaning liquid (dilute hydrofluoric acid), an SPM cleaning liquid (a mixture of sulfuric acid and hydrogen peroxide), an SC-1 cleaning liquid (a mixture of ammonia water, hydrogen peroxide, and pure water), an SC-2 cleaning liquid (a mixture of hydrochloric acid, hydrogen peroxide, and pure water), or pure water (deionized water). However, the type of processing liquid is not limited, and liquids other than those listed above may also be used.

[0036] Fig. 3 is a diagram schematically showing a portion of the processing liquid supply unit 40 and the configuration of the particle counter 50. Fig. 4 is a vertical cross-sectional view taken along line AA in Fig. 3. That is, Fig. 4 is a vertical cross-sectional view of a portion of the supply pipe 43 and the flow cell 44 taken along a direction perpendicular to Fig. 3. As shown in Figs. 2 to 4, the supply pipe 43 has an upstream pipe 431 and a downstream pipe 432. The flow cell 44 is located downstream of the pump 45 and the valve 46 in the supply pipe 43.

[0037] The upstream pipe 431 is a pipe located upstream of the flow cell 44. The downstream pipe 432 is a pipe located downstream of the flow cell 44. The flow cell 44 is adjacent to the downstream side of the upstream pipe 431 and the upstream side of the downstream pipe 432. The flow cell 44 has a plurality of branch flow paths 440 arranged in parallel with one another. The upstream end of each of the branch flow paths 440 is continuous with the downstream end of the upstream pipe 431. Furthermore, the downstream end of each of the branch flow paths 440 is continuous with the upstream end of the downstream pipe 432. In other words, the flow cell 44 has a plurality of branch flow paths 440 connected to the supply pipe 43. Furthermore, the opening at the downstream end of the upstream pipe 431 corresponds to the "supply port" of the present invention. In other words, the "supply port" of the present invention is one of the openings in the supply pipe 43. A treatment liquid, which is a fluid, is supplied to the "supply port" from a supply source 42 located upstream of the upstream pipe 431. That is, each of the branched flow paths 440 is connected to a "supply port" through which the processing liquid, which is a fluid, is supplied.

[0038] The upstream pipe 431, the downstream pipe 432, and the plurality of branch flow paths 440 are each capable of passing particles and bubbles mixed in the processing liquid along with the processing liquid. Note that particles are solids such as dirt, dust, foreign matter, and the like. Also, bubbles are generated when the pump 45 is driven, for example.

[0039] Furthermore, each of the plurality of branch flow paths 440 passes the processing liquid that has flowed in from the internal flow path 430 of the upstream piping 431. Then, the processing liquid that has passed through each of the plurality of branch flow paths 440 joins together and flows into the internal flow path 430 of the downstream piping 432. In this manner, in this embodiment, by providing the flow cell 44 inline in the supply piping 43, the processing liquid can be allowed to proceed downstream as is and used to process the substrate W while detecting the presence or absence of particles or bubbles in the processing liquid in the flow cell 44, as will be described later.

[0040] Fig. 5 is a cross-sectional view seen from position BB in Fig. 4. Fig. 5 also illustrates a light source 51, light-receiving elements 52a, 52b, ..., 52z, and a measurement light 510, which will be described later. In Fig. 4 and Fig. 5, the multiple branch flow paths 440 are referred to as branch flow paths 440a, 440b, ..., 440z in order to distinguish them from one another. The multiple branch flow paths 440a, 440b, ..., 440z may be arranged adjacent to one another in a single row, as shown in Fig. 5, or may be arranged adjacent to one another across multiple rows.

[0041] In this embodiment, the sum of the cross-sectional areas of the branch flow paths 440a, 440b, 440z, and 440z is greater than the cross-sectional area of ​​the internal flow path 430 of the upstream pipe 431. That is, in this embodiment, the sum of the cross-sectional areas of the branch flow paths 440a, 440b, 440z is greater than the cross-sectional area of ​​the supply pipe 43 upstream of the branch flow paths 440a, 440b, 440z. Therefore, the flow velocity of the treatment liquid decreases when it travels from the upstream pipe 431 to one of the branch flow paths 440. That is, the flow velocity of the treatment liquid decreases when it travels from the supply pipe 43 to the branch flow path 440 via the "supply port" of the present invention. In this embodiment, with such a simple structure, the flow velocity of the treatment liquid containing particles or bubbles can be reduced in each branch flow path 440. The effect of reducing the flow velocity of the treatment liquid in each branch flow path 440 will be described later.

[0042] On the other hand, the flow path cross-sectional area of ​​branch flow path 440a, the flow path cross-sectional area of ​​branch flow path 440b, ..., and the flow path cross-sectional area of ​​branch flow path 440z are each smaller than the flow path cross-sectional area of ​​internal flow path 430 of upstream piping 431. Therefore, a small amount of processing liquid containing particles or bubbles passes through each branch flow path 440. That is, a very small amount (approximately one) of particles or bubbles can be advanced at a time through each branch flow path 440.

[0043] The particle counter 50 detects the number and size of particles and bubbles passing through each branch flow path 440. The particle counter 50 is fixed to the inner wall of the chamber 10 or the like so as to be located near the flow cell 44. The particle counter 50 has a light source 51 and multiple light receiving elements 52. In this embodiment, one light source 51 is provided for all of the multiple branch flow paths 440. One light receiving element 52 is provided for each branch flow path 440. The light source 51, the multiple light receiving elements 52, and the control unit 70 can also be considered to be included in the flow cell 44. The "abnormality reporting unit" described below and the camera 53 of the first modified example can also be considered to be included in the flow cell 44.

[0044] The light source 51 is a light-emitting device that emits measurement light 510 for detecting the number and size of particles and bubbles passing through each of the multiple branch flow paths 440. That is, the light source 51 emits light to the multiple branch flow paths 440. More specifically, the light source 51 emits sheet laser light, which is an example of the measurement light 510, substantially continuously so that the light reaches all of the multiple branch flow paths 440a, 440b, ..., 440z. The sheet laser light spreads in the direction of the paper surface of FIG. 5. Furthermore, the light source 51 emits the measurement light 510 to all of the multiple branch flow paths 440a, 440b, ..., 440z from one side perpendicular to the direction in which the treatment liquid passes through the multiple branch flow paths 440a, 440b, ..., 440z.

[0045] The measurement light 510 emitted from the light source 51 is irradiated onto each of the multiple branch flow paths 440. As described above, a very small number of particles or bubbles (approximately one) may pass through each of the branch flow paths 440a, 440b, ..., 440z. When the measurement light 510 hits a particle or bubble, it is reflected and scattered. In some cases, when the measurement light 510 hits a particle or bubble, the light is reflected behind the particle or bubble, generating diffracted light. Hereinafter, such scattered light and / or diffracted light will be referred to as "detection target light 521." Note that when the particle or bubble is larger, the detection target light 521 with a higher intensity is generated when the measurement light 510 hits it.

[0046] Each of the plurality of light receiving elements 52 is provided corresponding to one of the plurality of branch flow paths 440. In FIG. 5, the plurality of light receiving elements 52 are referred to as light receiving elements 52a, 52b, ..., 52z in order to distinguish one from another. Light receiving element 52a is disposed on the opposite side of light source 51 with respect to branch flow path 440a. Light receiving element 52b is disposed on the opposite side of light source 51 with respect to branch flow path 440b. ... Light receiving element 52z is disposed on the opposite side of light source 51 with respect to branch flow path 440z. In other words, each of the plurality of light receiving elements 52 is disposed on the opposite side of light source 51 with respect to each of the plurality of branch flow paths 440.

[0047] Each of the light-receiving elements 52 is a semiconductor light-receiving element such as a photodiode or a phototransistor. A processing circuit (not shown) is connected to each of the light-receiving elements 52. Measurement light 510 irradiated from the light source 51 toward the branch flow path 440a and detection target light 521 generated when the measurement light 510 strikes particles or bubbles passing through the branch flow path 440a are focused on a detection element of the processing circuit connected to the light-receiving element 52a. This allows the light-receiving element 52a to receive the measurement light 510 and the detection target light 521. A signal based on the measurement light 510 and the detection target light 521 incident on the light-receiving element 52a is output from the processing circuit connected to the light-receiving element 52a and input to the control unit 70.

[0048] Similarly, the measurement light 510 emitted from the light source 51 toward the branch flow path 440b and the detection target light 521 generated when the measurement light 510 hits particles or bubbles passing through the branch flow path 440b are focused on a detection element of the processing circuit connected to the light-receiving element 52b. This allows the light-receiving element 52b to receive the measurement light 510 and the detection target light 521. A signal based on the measurement light 510 and the detection target light 521 incident on the light-receiving element 52b is output from the processing circuit connected to the light-receiving element 52b and input to the control unit 70. Similarly, the measurement light 510 emitted from the light source 51 toward the branch flow path 440z and the detection target light 521 generated when the measurement light 510 hits particles or bubbles passing through the branch flow path 440z are focused on a detection element of the processing circuit connected to the light-receiving element 52z. This allows the light-receiving element 52z to receive the measurement light 510 and the detection target light 521. A signal based on the measurement light 510 and the light to be detected 521 incident on the light receiving element 52z is output from a processing circuit connected to the light receiving element 52z and input to the control unit .

[0049] That is, each of the multiple light receiving elements 52 can receive detection target light 521 generated when light from the light source 51 strikes particles or bubbles contained in the processing liquid passing through the corresponding branch flow path 440, and output a signal corresponding to the received detection target light 521. Fig. 6 is a graph showing an example of a signal output from each light receiving element 52. In Fig. 6, the horizontal axis represents time, and the vertical axis represents the magnitude of the signal output from the light receiving element 52.

[0050] The magnitude of the signal output from each light-receiving element 52 is proportional to the intensity of the detection target light 521 received by that light-receiving element 52. That is, each of the multiple light-receiving elements 52 can output a signal corresponding to the intensity of the detection target light 521 received. As described above, the detection target light 521 has a higher intensity than the measurement light 510. Therefore, when a particle or a bubble passes through the branch flow path 440, the intensity of the detection target light 521 generated by the measurement light 510 hitting the particle or bubble momentarily increases. As a result, the signal output from the light-receiving element 52 that receives the detection target light 521 whose intensity has momentarily increased rises in a pulse shape, as shown in FIG. 6.

[0051] In particular, as described above, in the present invention, particles or bubbles in the processing liquid move at a slower speed in each branch flow path 440. Furthermore, particles or bubbles move in extremely small numbers (approximately one at a time) in each branch flow path 440. Therefore, when the measurement light 510 hits a particle or bubble, a clearer change in intensity of the light to be detected 521 occurs.

[0052] When many particles or bubbles pass through the branch flow path 440 at the same time, or when larger particles or bubbles pass through, the signal output from the light receiving element 52 becomes even larger.

[0053] The control unit 70 is an information processing device that controls each part of the substrate processing apparatus 1. Fig. 7 is a control block diagram of the substrate processing apparatus 1. As conceptually shown in Fig. 7, the control unit 70 is configured by a computer having a processor 71 such as a CPU, a memory 72 such as a RAM, and a storage unit 73 such as a hard disk drive.

[0054] A computer program P is stored in the storage unit 73. As shown in Fig. 7, the control unit 70 is communicatively connected, via wire or wirelessly, to the chuck pin switching mechanism 23 of the substrate holding unit 20, the motor 32 of the rotation mechanism 30, the nozzle 41, the pump 45, and the valve 46 of the processing liquid supply unit 40, the light source 51 and the plurality of light receiving elements 52 (including a processing circuit) of the particle counter 50, the lifting mechanism for the cup 60, and the display unit 80. The control unit 70 controls the operation of each of the above units in accordance with the computer program P. This allows the cleaning process of the substrate W in the substrate processing apparatus 1 and the detection of particles or bubbles contained in the processing liquid passing through each branch flow path 440 to proceed.

[0055] The detection of particles or bubbles contained in the processing liquid passing through the branch flow paths 440 by the control unit 70 will be described in more detail below. As described above, each of the multiple light-receiving elements 52 receives the detection target light 521 generated when light from the light source 51 strikes particles or bubbles contained in the processing liquid passing through the corresponding branch flow path 440, and inputs a signal corresponding to the received detection target light 521 to the control unit 70. When the magnitude of the input signal exceeds a predetermined threshold value St, the control unit 70 determines that particles or bubbles have passed through the corresponding branch flow path 440. Furthermore, the control unit 70 calculates the number of times that a pulse-like signal exceeding the threshold value St is detected (two times in the example of FIG. 6 ) as the number of times that particles or bubbles have passed through the corresponding branch flow path 440, i.e., the number of particles or bubbles contained in the processing liquid in the corresponding branch flow path 440. Furthermore, the control unit 70 similarly calculates the number of particles or bubbles contained in the processing liquid in the corresponding branch flow path 440 for the signals input from all the light receiving elements 52, and by adding these up, the number of particles or bubbles in the entire processing liquid can be accurately detected.

[0056] As described above, the magnitude of the signal output from each light-receiving element 52 is proportional to the intensity of the detection target light 521 received by that light-receiving element 52. Furthermore, larger particles or bubbles generate more intense detection target light 521 when hit by the measurement light 510. Therefore, the control unit 70 calculates the size of the particles or bubbles that have passed through the corresponding branch flow path 440 based on the magnitude of the signal from each light-receiving element 52. However, the control unit 70 may calculate only the number or size of the particles or bubbles. That is, the control unit 70 may calculate the number or size of the particles or bubbles contained in the processing liquid based on the change in the intensity of the signal output from the light-receiving element 52. The control unit 70 may also calculate the size of the particles or bubbles based on the time during which the input signal exceeds the threshold value St (the period during which the signal continues to exceed the threshold value St).

[0057] As described above, in the present invention, the number and size of particles and bubbles can be detected with higher accuracy by reducing the flow rate of the processing liquid containing particles or bubbles in each branch flow path 440 and by allowing the particles or bubbles to advance in extremely small amounts in each branch flow path 440. Furthermore, by using a plurality of light receiving elements 52 to detect the detection target light 521 generated in all branch flow paths 440, particles or bubbles in the entire processing liquid can be detected with even higher accuracy.

[0058] Returning to FIG. 1 , the display unit 80 is electrically connected to the control unit 70. The control unit 70 displays the calculation results of the number and size of particles or bubbles contained in the processing liquid on a display, which is an example of the display unit 80. The content displayed on the display may be the numerical value of the calculation results of the number and size of particles or bubbles contained in the processing liquid, or a message indicating that the calculation results exceed the allowable range. By displaying such a message, the operator can stop the substrate processing apparatus 1 if the number or size of particles or bubbles exceeds the allowable range. This prevents the processing liquid from being used as is, which would result in a decrease in the quality of the substrates W when processed in a subsequent process.

[0059] However, the display unit 80 is not limited to a display, and may be, for example, a lamp that displays a warning or a speaker that emits a warning sound. Furthermore, the content displayed on the display unit 80 is not limited to the above. That is, the substrate processing apparatus 1 only needs to have an abnormality reporting unit that is the display unit 80 that outputs an abnormality signal when the calculation result of the number or size of particles or bubbles by the control unit 70 exceeds a predetermined value.

[0060] <2. Modifications> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

[0061] <2-1. First modified example> In the above embodiment, a plurality of light receiving elements 52 are provided to receive the detection target light 521 generated when light hits particles or bubbles passing through each branch flow path 440 of the flow cell 44. However, as shown in a first modified example in FIG. 8 , a single camera 53 may be provided to capture images of the plurality of branch flow paths 440. The camera 53 may have a plurality of light receiving elements (not shown) corresponding to each of the plurality of branch flow paths 440. Each of the plurality of light receiving elements may receive the detection target light 521 generated when light hits particles or bubbles and output a signal to the control unit 70. The control unit 70 can detect the number and size of particles or bubbles contained in the processing liquid based on the signals output from the plurality of light receiving elements.

[0062] <2-2. Second modified example> The particle counter 50 may also be configured to detect interference light between the detection target light 521 from particles or bubbles and the reference light. More specifically, first, the light source 51 irradiates the measurement light 510 toward each of the multiple branched flow paths 440 of the flow cell 44, and a portion of the measurement light 510 is reflected by a reference mirror to generate reference light. Then, interference light generated by interference between the detection target light 521 from particles or bubbles and the reference light is incident on a spectroscope, which separates the interference light into wavelengths. Furthermore, the light receiving element 52 detects the light amount (intensity) of the interference light for each wavelength, and the control unit 70 can calculate the number and size of the particles or bubbles based on the detection results.

[0063] That is, in the present invention, each of the multiple light-receiving elements corresponds to one of the multiple branched flow paths, and is capable of receiving scattered light or diffracted light generated when light from the light source strikes particles or bubbles contained in the processing liquid passing through the corresponding branched flow path, or interference light generated when the scattered light interferes with a reference light, and outputting a signal corresponding to the received scattered light, diffracted light, or interference light. Furthermore, each of the multiple light-receiving elements is capable of outputting a signal corresponding to the intensity of the received scattered light, diffracted light, or interference light. Furthermore, the control unit is capable of calculating the number or size of particles or bubbles contained in the processing liquid based on the signal output from the light-receiving element. Furthermore, in the above-mentioned first modified example, the camera is capable of receiving scattered light, diffracted light, or interference light and outputting a signal.

[0064] <2-3. Other variations> Furthermore, the flow cell 44 does not necessarily have to be provided inline with the supply pipe 43. That is, the flow cell 44 may be provided away from the supply pipe 43. The processing liquid for which the presence or absence of particles or bubbles has been detected in the flow cell 44 does not have to be used in the subsequent processing of the substrate W.

[0065] Furthermore, the elements appearing in the above-described embodiments and modifications may be combined in any manner as long as no contradictions arise. [Explanation of symbols]

[0066] 1: Substrate processing equipment 40: Processing liquid supply unit 41: Nozzle 42: Source 43: Supply piping 44: Flow cell 45: Pump 46: Valve 50: Particle counter 51 :Light source 52, 52a, 52b, 52z: light receiving element 53: Camera 70: Control unit 80:Display section 430: Internal flow path (of supply pipe) 431: (supply pipe) upstream pipe 432: Downstream piping (of supply piping) 440, 440a, 440b, 440z: Branch flow channels (of the flow cell) 510: Measurement light 521: Light to be detected (scattered light and / or diffracted light)

Claims

1. a plurality of branch flow paths connected to a supply port through which a fluid is supplied; a light source that irradiates the plurality of branch flow paths with light; a plurality of light receiving elements disposed on the opposite side of the light source with respect to each of the plurality of branch flow paths; a control unit that calculates the number or size of particles or bubbles contained in the fluid based on the signal output from the light receiving element; and each of the plurality of branch channels is capable of passing the particles or the bubbles; A flow cell in which each of the plurality of light-receiving elements corresponds to one of the plurality of branched flow paths, and is capable of receiving scattered light or diffracted light generated when light from the light source hits the particles or bubbles contained in the fluid passing through the corresponding branched flow path, or interference light generated when the scattered light interferes with a reference light, and outputting the signal corresponding to the received scattered light, diffracted light, or interference light.

2. 10. The flow cell of claim 1, A camera for capturing images of the plurality of branched flow paths and The camera has the plurality of light-receiving elements capable of receiving the scattered light, the diffracted light, or the interference light and outputting the signals, respectively.

3. 10. The flow cell of claim 1, each of the plurality of light receiving elements is capable of outputting the signal corresponding to the intensity of the received scattered light, diffracted light, or interference light; The control unit calculates the number or size of the particles or bubbles contained in the fluid based on a change in intensity of the signal output from the light-receiving element.

4. 4. The flow cell according to claim 1, wherein: The flow cell further comprises an abnormality reporting unit that outputs an abnormality signal when the result of calculation by the control unit on the number or size of the particles or bubbles exceeds a predetermined value.

5. a substrate processing apparatus for processing a substrate using the processing liquid as the fluid, a nozzle that ejects the processing liquid onto the substrate; a supply source that stores the processing liquid to be supplied to the nozzle; a supply pipe connecting the supply source and the nozzle; The flow cell of claim 1; and the supply port is an opening of the supply pipe, The substrate processing apparatus, wherein the flow rate of the processing liquid decreases when the processing liquid flows from the supply pipe through the supply port to the branch flow path.

6. 6. The substrate processing apparatus according to claim 5, The substrate processing apparatus, wherein a total value of the cross-sectional areas of the plurality of branch flow paths is larger than a cross-sectional area of ​​the supply pipe upstream of the branch flow paths.

7. 7. The substrate processing apparatus according to claim 5, The supply pipe is an upstream pipe that is a pipe located upstream of the flow cell; a downstream pipe that is a pipe located downstream of the flow cell; and an upstream end of each of the plurality of branch flow paths is continuous with a downstream end of the upstream pipe; a downstream end of each of the plurality of branch flow paths continuing to an upstream end of the downstream pipe;

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