Observation device

Abstract

To provide an observation device that allows a user to observe a flow of a specific type of gas among multiple types of gas present in an observation area.SOLUTION: An observation device 60 includes a background image 61, an imaging unit 62, a wavelength selection unit 63, and a computer. The imaging unit 62 has an imaging sensor 622 that takes a picture of the background image 61 through an observation area S where the airflow is present. The wavelength selection unit 63 is placed between the background image 61 and the imaging sensor 622. The wavelength selection unit 63 selectively transmits light of a specific wavelength. Therefore, the imaging unit 62 can capture an image of the background image 61 using light of the specific wavelength. Therefore, by applying background-type Schlieren imaging to the obtained photographed image, the computer can observe a flow of a specific type of gas among multiple types of gas present in the observation area.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an observation device for observing an air current. [Background technology]

[0002] Conventionally, there is known an apparatus for performing a cleaning process on a substrate such as a semiconductor wafer by supplying a processing liquid to the substrate. In this type of apparatus, even a slight change in airflow in the chamber can cause a deterioration in the quality of the product. For this reason, there is a demand for a technology that can observe the state of airflow in the chamber while performing a substrate cleaning process.

[0003] A known technique for observing airflow is, for example, the Background Oriented Schlieren (BOS) method. The Background Schlieren method is a method for calculating the state of airflow in an observation area by capturing a background image through the observation area where airflow is formed and measuring the distortion of the background image in the captured image.

[0004] A conventional apparatus using the background type Schlieren method is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-143917 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, when multiple types of gases are present in the observation area, the conventional background schlieren method measures the image distortion caused by the sum of the refractive indices of the mixed gases, and observes the flow of the mixed gas as a whole. For this reason, the conventional background schlieren method cannot observe the flow of a specific type of gas in a mixed gas.

[0007] The present invention has been made in consideration of the above circumstances, and has an object to provide an observation device that can observe the flow of a specific type of gas among multiple types of gases present in an observation area. [Means for solving the problem]

[0008] In order to solve the above problems, the first invention of the present application is an observation device for observing airflow, comprising: a background image; an imaging unit having an image sensor that captures the background image through an observation area in which the airflow exists; a wavelength selection unit that is disposed between the background image and the image sensor and selectively transmits light of a specific wavelength; and a computer that calculates the state of the airflow by a background-type Schlieren method using the image acquired by the imaging unit.

[0009] A second invention of the present application is the observation device of the first invention, wherein the wavelength selection section is an interference filter that transmits light of the specific wavelength.

[0010] A third aspect of the present invention is the observation device according to the first or second aspect of the present invention, wherein the specific wavelength is an absorption wavelength of a gas to be observed.

[0011] A fourth invention of the present application is an observation device of any one of the first to third inventions, comprising a beam splitter that splits light emitted from or reflected from the background image and transmitted through the observation area into a first optical path and a second optical path, a first imaging unit that is the imaging unit and is arranged in the first optical path, and a second imaging unit that is arranged in the second optical path, and the wavelength selection unit is arranged only in the first optical path of the first and second optical paths.

[0012] The fifth invention of the present application is an observation device for observing airflow, comprising: a background image; an imaging unit having an image sensor that captures the background image through an observation area in which the airflow exists; and a computer that calculates the state of the airflow by a background-type Schlieren method using the image acquired by the imaging unit, wherein the wavelength of light emitted or reflected from the background image is the absorption wavelength of the gas to be observed among the gases present in the observation area.

[0013] A sixth aspect of the present invention is the observation device of the fifth aspect of the present invention, further comprising a projector that projects the background image by light of the absorption wavelength onto a background surface on which the background image is to be placed. Effect of the Invention

[0014] According to the first to sixth aspects of the present invention, a background image can be captured using light of a specific wavelength. Therefore, the flow of a specific type of gas among multiple types of gases present in an observation area can be observed by the background Schlieren method.

[0015] In particular, according to the fourth aspect of the present invention, the first imaging section can observe the flow of a specific type of gas among multiple types of gas present in the observation area, and the second imaging section can observe the flow of all types of gas. [Brief description of the drawings]

[0016] [Figure 1] 1 is a vertical sectional view of a substrate processing apparatus; [Diagram 2] 4 is a block diagram showing electrical connections between a control unit and each unit in the substrate processing apparatus. FIG. [Diagram 3] FIG. 1 is a conceptual diagram of an observation device. [Figure 4] 1 is a graph showing an absorption spectrum of a gas. [Diagram 5] FIG. 1 is a conceptual diagram of an observation device equipped with two imaging units. [Figure 6] FIG. 1 is a conceptual diagram of an observation device equipped with a projector. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0018] <1. Overall configuration of substrate processing equipment> 1 is a vertical cross-sectional view of a substrate processing apparatus 1 equipped with an observation apparatus 60 according to one embodiment. The substrate processing apparatus 1 is an apparatus for supplying a processing liquid to a surface of a disk-shaped substrate W to clean the substrate W in a semiconductor wafer manufacturing process. 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, and a computer 50.

[0019] The chamber 10 is a housing containing a processing space 11 for processing a substrate W. The chamber 10 has a sidewall 12 surrounding the sides of the processing space 11, a top plate portion 13 covering an upper portion of the processing space 11, and a bottom plate portion 14 covering a lower portion of the processing space 11. The substrate holder 20, the rotating mechanism 30, and the nozzle 45 of the processing liquid supply unit 40 are housed inside the chamber 10. A load / unload port for loading and unloading the substrate W into and from the chamber 10, and a shutter for opening and closing the load / unload port are provided in a part of the sidewall 12.

[0020] The substrate holding unit 20 is a mechanism for holding the substrate W horizontally (in a position in which the normal line faces the vertical direction) 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 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 processing surface on which a pattern is to be formed facing upward. Each chuck pin 22 contacts the lower surface and outer periphery end surface of the peripheral portion 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.

[0021] The rotation mechanism 30 is a mechanism for rotating the substrate holding part 20. As shown in Fig. 1, the rotation mechanism 30 has a motor 31 and a support shaft 32. The support shaft 32 extends in the vertical direction, with its lower end connected to the motor 31 and its upper end fixed to the center of the lower surface of the spin base 21. When the motor 31 is driven, the support shaft 32 rotates about its axis 320. Then, together with the support shaft 32, the substrate holding part 20 and the substrate W held by the substrate holding part 20 also rotate about the axis 320.

[0022] The processing liquid supply unit 40 is a mechanism for supplying a processing liquid to the upper surface of the substrate W held by the substrate holding unit 20. The processing liquid supply unit 40 has a liquid supply source 41, a liquid supply pipe 42, a valve 43, a pump 44, and a nozzle 45. The liquid supply source 41 is a tank for storing the processing liquid before supply. Examples of the processing liquid that can be used include 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), a DHF cleaning liquid (dilute hydrofluoric acid), and pure water (deionized water).

[0023] The liquid supply pipe 42 is a pipe that connects the liquid supply source 41 and the nozzle 45. The valve 43 and the pump 44 are provided on the path of the liquid supply pipe 42. The nozzle 45 is disposed facing the upper surface of the substrate W. When the valve 43 is opened and the pump 44 is operated, the processing liquid is supplied from the liquid supply source 41 through the liquid supply pipe 42 to the nozzle 45. Then, the processing liquid is discharged from the nozzle 45 toward the center of the upper surface of the substrate W.

[0024] The processing liquid discharged from the nozzle 45 onto the upper surface of the substrate W spreads outward from the center of the substrate W due to centrifugal force caused by the rotation of the substrate W. The processing liquid scattered outward from the substrate W is collected in a cup (not shown) and then discharged to the outside of the chamber 10.

[0025] The computer 50 is an information processing device for controlling the operation of each part of the substrate processing apparatus 1. Fig. 2 is a block diagram showing electrical connections between the computer 50 and each part in the substrate processing apparatus 1. As conceptually shown in Fig. 2, the computer 50 has a processor 51 such as a CPU, a memory 52 such as a RAM, and a storage unit 53 such as a hard disk drive.

[0026] An operation control program P1 and an air current observation program P2 are stored in the storage unit 53. The operation control program P1 is a computer program for controlling the operation of each unit of the substrate processing apparatus 1 in order to execute processing of the substrate W in the substrate processing apparatus 1. The air current observation program P2 is a computer program for observing the state of the air current in the chamber 10 based on an image obtained from an imaging unit 62 described later.

[0027] 2, the computer 50 is electrically connected to the above-mentioned chuck pin 22, motor 31, valve 43, and pump 44. The computer 50 controls the operation of each of the above-mentioned parts according to an operation control program P1 stored in the storage unit 53. This allows the cleaning process of the substrate W in the substrate processing apparatus 1 to proceed. The computer 50 is also electrically connected to an imaging unit 62, which will be described later. The computer 50 performs an observation process of the airflow in the chamber 10 based on an image obtained from the imaging unit 62.

[0028] <2. Observation equipment> During the cleaning process of the substrate W, various air currents are generated in the chamber 10 due to the downflow of purified air, the discharge of the processing liquid, the evaporation of the processing liquid, the temperature change of the gas, etc. These air currents may affect the cleaning quality of the substrate W. Therefore, the substrate processing apparatus 1 is provided with an observation device 60 that observes the state of the air current in a predetermined observation area S in the chamber 10.

[0029] As shown in FIG. 1, the observation device 60 includes a background image 61, an imaging section 62, an interference filter 63, and the computer 50 described above.

[0030] The background image 61 is an image placed inside the chamber 10. The background image 61 may be a geometric repeating pattern such as dots or stripes, or may be a random pattern or design. The background image 61 is placed on the surface of a structure inside the chamber 10. The background image 61 is placed on a plane that intersects with the optical axis A of the observation device 60.

[0031] 1, a background image 61 is fixedly formed on the surface of a structure within the chamber 10. However, the background image 61 may be a projected image formed by projecting light onto the surface of the structure within the chamber 10 from outside the chamber 10.

[0032] The imaging unit 62 is a unit that captures a background image 61. The imaging unit 62 is disposed outside the chamber 10. A transparent window 15 is provided on the side wall 12 of the chamber 10. The imaging unit 62 captures a background image 61 in the chamber 10 through an interference filter 63, the window 15, and an observation area S. As shown in FIG. 1, the imaging unit 62 has an imaging optical system 621 and an imaging sensor 622. The imaging optical system 621 includes one or more lenses. The imaging sensor 622 includes an imaging element such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

[0033] The imaging sensor 622 receives light incident from the background image 61 through the observation area S, the window 15, the interference filter 63, and the imaging optical system 621. This allows a multi-tone captured image composed of a plurality of pixels to be obtained. The imaging sensor 622 also obtains a plurality of captured images by repeatedly capturing images at short time intervals. The obtained captured images are input from the imaging sensor 622 to the computer 50.

[0034] The computer 50 uses the captured image input from the imaging unit 62 to calculate the state of the airflow in the observation region S by a background oriented Schlieren (BOS) method.

[0035] The interference filter 63 is an optical filter that selectively transmits light of a specific wavelength λs. The interference filter 63 is an example of the "wavelength selection section" in the present invention. The interference filter 63 is disposed between the background image 61 and the imaging sensor 622. In this embodiment, the interference filter 63 is disposed between the window 15 of the chamber 10 and the imaging section 62. However, the interference filter 63 may be disposed inside the chamber 10. Also, the interference filter 63 may be disposed inside the imaging section 62.

[0036] Fig. 3 is a conceptual diagram of the observation device 60. A light ray L1 in Fig. 3 indicates light traveling from a part of the background image 61 toward the image sensor 622 when a specific type of gas G to be observed is not present in the observation area S. A light ray L2 in Fig. 3 indicates light traveling from a part of the background image 61 toward the image sensor 622 when the gas G is present in the observation area S.

[0037] As shown in FIG. 3, the light rays passing through the observation area S are displaced due to the difference in refractive index between the gas G and other gases when the gas G is present in the observation area S and when it is not present. This causes the incident positions of the light rays L1 and L2 to change at the position of the image sensor 622. As a result, the background image 61 is distorted in the captured image acquired by the image capturing unit 62. The computer 50 measures the distortion of the background image 61 in the captured image. Then, the computer 50 calculates the state of the airflow in the observation area S based on the measured distortion of the background image 61.

[0038] In this embodiment, an interference filter 63 is inserted on the optical path between the background image 61 and the imaging sensor 622. Therefore, among the light of all wavelengths λall contained in the light beams L1 and L2 incident on the interference filter 63, the light of the specific wavelength λs is selectively transmitted through the interference filter 63. Therefore, the imaging sensor 622 captures an image of the background image 61 using the light of the specific wavelength λs.

[0039] The specific wavelength λs does not necessarily have to be a wavelength in the visible range. For example, the specific wavelength λs may be a wavelength in the infrared range. In that case, the imaging sensor 622 may be a sensor capable of capturing infrared light.

[0040] FIG. 4 is a graph showing the absorption spectrum of a certain gas G. The horizontal axis of FIG. 4 shows the wavelength of light. The vertical axis of FIG. 4 shows the absorbance by gas G. As shown in FIG. 4, gas G shows high absorbance at a specific absorption wavelength λa. That is, gas G has the property of easily absorbing light of the absorption wavelength λa. The absorption wavelength λa varies depending on the type of gas. For example, oxygen, nitrogen, carbon dioxide, water vapor, etc. each have a different absorption wavelength λa. When gas G exists, light of the absorption wavelength λa is absorbed by gas G. As a result, the amount of light of the absorption wavelength λa decreases among the light of all wavelengths λall incident on gas G.

[0041] In this embodiment, the interference filter 63 is selected so that the specific wavelength λs, which is the wavelength of light passing through the interference filter 63, is the absorption wavelength λa of the gas G to be observed. In other words, an interference filter 63 is used in which the range of the absorption wavelength λa at least partially overlaps with the range of the specific wavelength λs.

[0042] Then, in the region of the observation region S where the gas G to be observed does not exist, the light of the specific wavelength λs transmitted through the gas G and the interference filter 63 is incident on the image sensor 622. Therefore, in the region of the captured image where the gas G does not exist, a relatively bright background image 61 appears due to the light of the specific wavelength λs. On the other hand, in the region of the observation region S where the gas G to be observed exists, the light of the specific wavelength λs is absorbed by the gas G, so the amount of light of the specific wavelength λs incident on the image sensor 622 decreases. Therefore, in the region of the captured image where the gas G exists, the background image 61 appears darker than in the region where the gas G does not exist.

[0043] The computer 50 recognizes a relatively dark portion in the captured image input from the imaging unit 62 as a region of interest where the gas G to be observed exists. The computer 50 also calculates the flow of the gas G in the observation region S by applying the background-type Schlieren method to the region of interest in the captured image. That is, the computer 50 measures the distortion of the background image 61 in the region of interest in the captured image, and calculates the flow of the gas G in the observation region S based on the measured amount of distortion.

[0044] As described above, in the observation device 60, by using the interference filter 63, it is possible to obtain an image captured by light of a specific wavelength λs corresponding to the gas G to be observed. Therefore, by applying the background type Schlieren method to the obtained captured image, it is possible to observe the flow of a specific type of gas G among multiple types of gases present in the observation region S.

[0045] The computer 50 calculates the flow of the specific gas G in the observation area S by the above method while performing the cleaning process of the substrate W. Then, the computer 50 monitors whether the calculated state of the air flow is within a predetermined allowable range. If the calculated state of the air flow is outside the allowable range, the computer 50 executes anomaly response control. The anomaly response control may be, for example, displaying a warning on a display unit such as a display, turning on a warning lamp, or sounding a warning sound. The anomaly response control may also be outputting information indicating an anomaly to an external terminal. The anomaly response control may also be stopping or limiting the cleaning process of the substrate W. This allows a user of the substrate processing apparatus 1 to recognize that the state of the air flow in the observation area S is outside the allowable range.

[0046] <3. Modifications> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. Various modified examples will be described below, focusing on the differences from the above embodiment.

[0047] <3-1. First modified example> In the above embodiment, the observation device 60 captures the background image 61 with one imaging unit 62. However, by branching the optical path, the background image 61 may be captured with a plurality of imaging units 62. Fig. 5 is a conceptual diagram of an observation device 60 equipped with two imaging units (hereinafter referred to as a first imaging unit 62A and a second imaging unit 62B).

[0048] The observation device 60 in Fig. 5 includes a first imaging section 62A, a second imaging section 62B, and a beam splitter 64. The beam splitter 64 is disposed between the observation area S and the two imaging sections 62A and 62B. Light emitted from or reflected by the background image 61 and transmitted through the observation area S is split into a first optical path PA and a second optical path PB by the beam splitter 64. The first imaging section 62A is disposed on the first optical path PA. The second imaging section 62B is disposed on the second optical path PB.

[0049] In the first optical path PA, an interference filter 63 is disposed, as in the above embodiment. Therefore, in the first optical path PA, light of a specific wavelength λs transmitted through the interference filter 63 is incident on the first imaging unit 62A. Therefore, the first imaging unit 62A captures an image of the background image 61 by the specific wavelength λs. On the other hand, in the example of FIG. 5, the interference filter 63 is not disposed on the second optical path PB. Therefore, in the second optical path PB, light of all wavelengths λall is incident on the second imaging unit 62B. Therefore, the second imaging unit 62B captures an image of the background image 61 by all wavelengths λall.

[0050] 5, the interference filter 63 is disposed only in the first optical path PA out of the first optical path PA and the second optical path PB. In this manner, the computer 50 can observe the flow of a specific type of gas G among the multiple types of gases present in the observation region S by using the captured image obtained from the first imaging unit 62A, and can observe the flow of all types of gas by using the captured image obtained from the second imaging unit 62B.

[0051] Also, an interference filter 63 that transmits light of different wavelengths may be arranged in the first optical path PA and the second optical path PB. In this way, different types of gas flows can be observed in the first imaging unit 62A and the second imaging unit 62B. Also, the optical path may be branched into three or more, and a different interference filter 63 may be arranged in each optical path.

[0052] <3-2. Second modified example> In the above embodiment, the interference filter 63 is used to selectively allow light having the absorption wavelength λa of the gas G to be observed to enter the imaging unit 62. However, without using the interference filter 63, the wavelength of the light itself emitted from or reflected by the background image 61 may be set as the absorption wavelength λa of the gas G to be observed. For example, the wavelength of the illumination light that illuminates the background image 61 may be set as the absorption wavelength λa of the gas G to be observed.

[0053] Alternatively, the background image 61 may be projected by a projector 65. Fig. 6 is a conceptual diagram of an observation device 60 equipped with a projector 65. In the example of Fig. 6, the projector 65 projects the background image 61 onto a background surface on which the background image 61 is to be placed. The wavelength of the projection light from the projector 65 is set to the absorption wavelength λa of the gas G to be observed.

[0054] In this way, the background image 61 itself is formed at the absorption wavelength λa of the gas G to be observed. Therefore, light with the absorption wavelength λa can be made incident on the imaging section 62 without using an interference filter 63 for selecting a wavelength. Therefore, the computer 50 can observe the flow of a specific type of gas G among the multiple types of gases present in the observation area S, using the captured image obtained from the first imaging section 62A.

[0055] Also, for example, the background image 61 may be formed by a light source arranged in a plane, such as a display. Then, light having an absorption wavelength λa of the gas G to be observed may be emitted from the background image 61 displayed by the light source arranged in a plane.

[0056] <3-3. Other variations> In the above embodiment and the first modified example, the interference filter 63 is used as a wavelength selection section that selectively transmits light of a specific wavelength λs. However, the wavelength selection section is not limited to the interference filter 63, and may be a prism, a spectroscope, or the like.

[0057] Furthermore, when the absorption spectrum of the gas G to be observed has peak values ​​at multiple wavelengths, the gas G may be observed by acquiring multiple images using the multiple wavelengths as specific wavelengths and combining the images.

[0058] In the above embodiment, an apparatus for performing a cleaning process on a substrate W has been described. However, the apparatus in which the observation apparatus of the present invention is mounted may be an apparatus for performing a process other than a cleaning process. Furthermore, the apparatus in which the observation apparatus of the present invention is mounted may be an apparatus for performing a process on an object other than a substrate W.

[0059] However, in an apparatus that supplies a processing liquid to a substrate W for precision electronic components such as a semiconductor wafer, it is necessary to extremely precisely control the state of airflow within the chamber 10. For this reason, in an apparatus that supplies a processing liquid to the substrate W, it is particularly significant to install the observation device of the present invention.

[0060] The observation device of the present invention is not limited to a device to be mounted on a specific processing device, but may be a device for general use. The observation device may be one used outdoors. The observation device may be one in which the projector 65 that projects the background image 61 and the imaging unit 62 are integrally configured.

[0061] Furthermore, the elements appearing in the above-described embodiments and modifications may be combined as appropriate or some of them may be deleted to the extent that no contradictions arise. [Explanation of symbols]

[0062] 1. Substrate Processing Equipment 10. Chamber 20 Board holding part 30 Rotation mechanism 40 Processing liquid supply section 50 Computer 60 Observation Equipment 61 Background Images 62 Imaging unit 62A First Imaging Unit 62B Second imaging unit 63 Interference Filters 64 Beam splitter 65 Projector 621 Imaging Optical System 622 Image Sensor A optical axis G Gas L1 ray L2 ray PA 1st optical path PB 2nd optical path S Observation area W substrate λa Absorption wavelength λs Specific wavelength

Claims

1. An observation device for observing an air flow, comprising: A background image and an imaging unit having an image sensor that captures the background image through an observation area where the airflow exists; a wavelength selection unit disposed between the background image and the image sensor, the wavelength selection unit selectively transmitting light of a specific wavelength; a computer that calculates the state of the airflow by a background type Schlieren method using the image acquired by the imaging unit; An observation device comprising:

2. The observation device according to claim 1, The wavelength selection unit is an interference filter that transmits light of the specific wavelength.

3. The observation device according to claim 1 or 2, An observation apparatus, wherein the specific wavelength is an absorption wavelength of a gas to be observed.

4. The observation device according to claim 1 or 2, a beam splitter that splits light emitted from or reflected by the background image and transmitted through the observation area into a first optical path and a second optical path; A first imaging unit that is the imaging unit disposed in the first optical path; A second imaging unit disposed in the second optical path; Equipped with The observation device, wherein the wavelength selection unit is disposed only in the first optical path out of the first optical path and the second optical path.

5. An observation device for observing an air flow, comprising: A background image and an imaging unit having an image sensor that captures the background image through an observation area where the airflow exists; a computer that calculates the state of the airflow by a background type Schlieren method using the image acquired by the imaging unit; Equipped with An observation device, wherein the wavelength of light emitted from or reflected from the background image is an absorption wavelength of a gas that is to be observed among gases present in the observation area.

6. The observation device according to claim 5, a projector that projects the background image onto a background surface on which the background image is to be placed, using light of the absorption wavelength; The observation device further comprises:

Images