Information acquisition device and information acquisition method

Abstract

In this information acquisition device and information acquisition method for measuring information about a specific substance that exists in a flow passage provided in a flow cell while allowing a fluid to flow through the flow passage, it is possible to measure said information while controlling the flow rate of the fluid in the flow passage. In the information acquisition device and the information acquisition method according to the present invention, a flow passage is formed in a flow cell by providing a cell section with a transparent member to block an opening of the cell section, and an adjustment unit is provided in the cell section. The adjustment unit changes the area of a cross section, of the flow passage, that is orthogonal to the flowing direction of the fluid, thereby controlling the flow rate of the fluid flowing through the flow passage of the flow cell.

Description

Information acquisition device and information acquisition method

[0001] This invention relates to an information acquisition device and method for measuring information about a specific substance present in a flow channel provided in a flow cell while flowing a fluid through the flow channel. The disclosures in the specification, drawings, and claims of the following Japanese patent application are incorporated herein by reference in their entirety: Japanese Patent Application No. 2024-153654 (filed September 6, 2024).

[0002] Substrate processing apparatuses are known that supply processing liquids, such as chemicals and rinses, to substrates to perform processing. For example, in the apparatus described in Patent Document 1, a phosphoric acid aqueous solution is used in a processing tank to etch away a silicon nitride film formed on the substrate. The phosphoric acid aqueous solution used in the etching process is circulated and reused, and the phosphoric acid aqueous solution is returned to the processing tank through a circulation line. A concentration meter is attached to the circulation line to measure the concentration of a specific substance contained in the phosphoric acid aqueous solution flowing through the circulation line (equivalent to an example of "information about the specific substance" in the present invention).

[0003] Japanese Patent Application Laid-Open No. 2013-21066

[0004] The concentration meter corresponds to an example of an information acquisition device of the present invention and is configured as follows. The concentration meter measures the concentration of a specific substance (e.g., silicon concentration) in a solution by flowing a phosphoric acid aqueous solution through a flow cell and measuring the absorbance of light of a specific wavelength. As will be described in detail later, this measurement depends on the speed of the phosphoric acid aqueous solution flowing through the flow cell. This can lead to the following problems. For example, when estimating the end point of an etching process in a processing bath by monitoring changes in absorbance in a circulation line, if the flow rate of the phosphoric acid aqueous solution in the flow cell differs significantly from the flow rate of the phosphoric acid aqueous solution in the processing bath, the estimation accuracy will decrease. It is also possible to replace the flow cell depending on the process conditions in the processing bath. However, replacing the flow cell requires a temporary interruption of substrate processing, which reduces work efficiency.

[0005] This problem is not limited to measuring the concentration of a specific substance in an apparatus that uses a phosphoric acid aqueous solution circulated through a treatment tank, but is common to any technology that measures information about a specific substance present in a flow path provided in a flow cell while a fluid is flowing through the flow path. However, no specific configuration that solves this problem has existed in the past.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an information acquisition device and information acquisition method that measures information about a specific substance present in a flow channel provided in a flow cell while flowing a fluid through the flow channel, and that enables the measurement of the information while controlling the flow rate of the fluid within the flow channel.

[0007] A first aspect of the present invention is an information acquisition device comprising: a flow cell having a flow path for flowing a fluid; and a total reflection measurement unit that measures information about a specific substance present in the flow path through which the fluid is flowing. The flow cell has an inlet for introducing the fluid and an outlet for discharging the fluid, and comprises a cell portion that extends from the inlet to the outlet to form a part of the flow path; and a transparent member that is transparent to a wavelength range that includes the absorption spectrum of the specific substance and is provided in the cell portion between the inlet and the outlet to close an opening provided in the cell portion, thereby forming the flow path in cooperation with the cell portion. The total reflection measurement unit comprises a light-emitting unit that irradiates the transparent member with light having directionality in the wavelength range so that the light is totally reflected inside the transparent member, and a light-receiving unit that receives light that has been totally reflected by the transparent member and then exits the transparent member. The cell portion has an adjustment unit that adjusts the cross-sectional area of ​​the flow path perpendicular to the flow direction of the fluid.

[0008] a transparent member that is transparent to a wavelength range that includes the absorption spectrum of the specific substance and that is disposed in the cell portion between the inlet and the outlet to block an opening provided in the cell portion, thereby forming the flow path in cooperation with the cell portion; flowing the fluid through the flow path of the flow cell; irradiating the transparent member with light having directionality in the wavelength range so that the light is totally reflected inside the transparent member, and receiving the light that has been totally reflected by the transparent member and then exits the transparent member to measure information about the specific substance present in the flow path through which the fluid is flowing; and adjusting a cross-sectional area of ​​the flow path perpendicular to the flow direction of the fluid before measuring the information.

[0009] In the invention configured in this manner, a flow path is formed in the flow cell by providing a transparent member in the cell portion so as to cover the opening of the cell portion, and an adjustment portion is provided in the cell portion. The adjustment portion changes the cross-sectional area of ​​the flow path perpendicular to the flow direction of the fluid, thereby controlling the flow rate of the fluid flowing through the flow path of the flow cell.

[0010] As described above, according to the present invention, it is possible to measure information about a specific substance present in a flow channel of a flow cell while controlling the flow rate of a fluid in the flow channel. Not all of the components of each of the above-described aspects of the present invention are essential, and in order to solve some or all of the above-described problems or achieve some or all of the effects described in this specification, some of the components may be modified, deleted, replaced with new components, or some of the limitations may be removed, as appropriate. Furthermore, in order to solve some or all of the above-described problems or achieve some or all of the effects described in this specification, some or all of the technical features included in one aspect of the present invention described above may be combined with some or all of the technical features included in another aspect of the present invention described above to form an independent aspect of the present invention.

[0011] 1 is a plan view showing a schematic configuration of a substrate processing system equipped with an information acquisition device according to the present invention. FIG. 2 is a diagram showing the configuration of a first embodiment of a substrate processing apparatus equipped with an information acquisition device according to the present invention. FIG. 3 is a perspective view showing an embodiment of an information acquisition device according to the present invention. FIG. 4 is a diagram schematically showing the cross-sectional structure and operation of the information acquisition device shown in FIG. 3. FIG. 5 is a diagram schematically showing the cross-sectional structure and operation of the information acquisition device shown in FIG. 3. FIG. 6 is a diagram schematically showing the configuration and operation of a total reflection measurement unit. FIG. 7 is a flowchart showing the operation of the substrate processing apparatus shown in FIG. 2. FIG. 8 is a diagram schematically showing a change in flow rate of a chemical liquid with a change in flow path height and the flow rate dependency of a concentration value when the concentration of a specific substance is measured by the information acquisition device in parallel with a chemical processing. FIG. 9 is a diagram schematically showing a change in flow rate of a chemical liquid with a change in flow path height and the flow rate dependency of a concentration value when the concentration of a specific substance is measured by the information acquisition device in parallel with a rinse processing. FIG. 10 is a diagram showing the configuration of a second embodiment of a substrate processing apparatus equipped with an information acquisition device according to the present invention. FIG. 11 is a diagram showing the configuration of a third embodiment of a substrate processing apparatus equipped with an information acquisition device according to the present invention.

[0012] FIG. 1 is a plan view showing the schematic configuration of a substrate processing system equipped with an information acquisition device according to the present invention. This is not an external view of the substrate processing system 100, but rather a schematic view showing the internal structure of the substrate processing system 100 by excluding the exterior wall panels and other components. The substrate processing system 100 is a single-wafer processing apparatus installed, for example, in a clean room, that processes substrates S, each of which has a circuit pattern or the like (hereinafter referred to as a "pattern") formed on only one main surface. The substrates are processed using a processing solution in a processing unit installed in the substrate processing system 100. In this specification, the pattern-formed surface (one main surface) of the two main surfaces of the substrate on which the pattern is formed is referred to as the "front surface," and the opposite main surface on which the pattern is not formed is referred to as the "rear surface." The surface facing downward is referred to as the "bottom surface," and the surface facing upward is referred to as the "top surface." In this specification, the "pattern-formed surface" refers to the surface of the substrate on which a concave-convex pattern is formed in any region.

[0013] Here, the "substrate" in this embodiment can be any of various substrates such as semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays, glass substrates for plasma displays, substrates for FEDs (Field Emission Displays), substrates for optical disks, substrates for magnetic disks, substrates for magneto-optical disks, etc. The following description will be given with reference to the drawings, taking as an example a substrate processing apparatus used primarily for processing semiconductor wafers, but the invention can also be applied to processing the various substrates exemplified above.

[0014] As shown in FIG. 1 , the substrate processing system 100 includes a substrate processing area 110 where disk-shaped substrates S are processed. An indexer unit 120 is provided adjacent to the substrate processing area 110. The indexer unit 120 includes a container holder 121 capable of holding a plurality of containers C for accommodating the substrates S (e.g., a FOUP (Front Opening Unified Pod), an SMIF (Standard Mechanical Interface) pod, or an OC (Open Cassette) that accommodates a plurality of substrates S in a sealed state). The indexer unit 120 also includes an indexer robot 122 that accesses the containers C held in the container holder 121 to remove unprocessed substrates S from the containers C or store processed substrates S in the containers C. Each container C accommodates a plurality of substrates S in a substantially horizontal position.

[0015] The indexer robot 122 comprises a base 122a fixed to the apparatus housing, an articulated arm 122b rotatable about a vertical axis relative to the base 122a, and a hand 122c attached to the tip of the articulated arm 122b. The hand 122c is structured so that a substrate S can be placed on its upper surface and held thereon. Indexer robots having such articulated arms and hands for holding substrates are well known, and therefore a detailed description thereof will be omitted.

[0016] In the substrate processing area 110, a mounting table 112 is provided so that a substrate S from an indexer robot 122 can be placed thereon. In addition, a substrate transport robot 111 is arranged approximately in the center of the substrate processing area 110 in a plan view. Furthermore, a plurality of processing units 1 are arranged surrounding the substrate transport robot 111. The substrate transport robot 111 randomly accesses these processing units 1 to hand over the substrate S. Meanwhile, each processing unit 1 performs a predetermined process on the substrate S. In this embodiment, one of these processing units 1 corresponds to a substrate processing apparatus 1 equipped with an information acquisition device according to the present invention.

[0017] 2 is a diagram showing the configuration of a first embodiment of a substrate processing apparatus equipped with an information acquisition device according to the present invention. The substrate processing apparatus 1 is a single-wafer type apparatus that processes substrates S one by one. The substrate processing apparatus 1 includes a box-shaped chamber 2, a spin chuck 3 that holds the substrate S horizontally within the chamber 2 and rotates the substrate S about a vertical rotation axis A1 that passes through the center of the substrate S, a processing liquid supply unit 4 that discharges a processing liquid toward the substrate S held on the spin chuck 3, and a cylindrical cup 5 that receives the processing liquid discharged from the substrate S.

[0018] The spin chuck 3 includes a disk-shaped spin base 31 held in a horizontal position, a plurality of chuck pins 32 that hold the substrate S in a horizontal position above the spin base 31, a spin shaft 33 extending downward from the center of the spin base 31, and a spin motor 34 that rotates the spin shaft 33 to rotate the substrate S and the spin base 31 about a rotation axis A1. The spin chuck 3 is not limited to a clamping type chuck that brings the plurality of chuck pins 32 into contact with the peripheral edge surface of the substrate S, but may also be a vacuum type chuck that holds the substrate S horizontally by attracting the back surface (lower surface) of the substrate S, which is the surface on which devices are not formed, to the upper surface of the spin base 31.

[0019] The processing liquid supply unit 4 includes a chemical liquid supply system that supplies a chemical liquid to the substrate S and a rinse liquid supply system that supplies a rinse liquid to the substrate S. The chemical liquid supply system includes a chemical liquid nozzle 41 that discharges a chemical liquid downward toward the upper surface of the substrate S held by the spin chuck 3, a nozzle moving unit 42 that moves the chemical liquid nozzle 41 between a processing position (position indicated by a solid line in FIG. 2 ) and a retracted position (position indicated by a dotted line in FIG. 2 ), and a bottomed, cylindrical standby pot 43 that is located below the retracted position of the chemical liquid nozzle 41. The chemical liquid nozzle 41 and the standby pot 43 are located within the chamber 2. The processing position is a position where the chemical liquid discharged from the chemical liquid nozzle 41 lands on the upper surface of the substrate S, and the retracted position is a position where the chemical liquid nozzle 41 is retracted so that the chemical liquid nozzle 41 and the substrate S do not overlap in a plan view. The chemical liquid is, for example, BHF (Buffered Hydrogen Fluoride), and a chemical liquid supply source (not shown) that supplies the chemical liquid is connected to the chemical liquid nozzle 41 by piping 44. Therefore, when a valve 61 provided in the fluid box 6 is opened, the chemical liquid is sent to the chemical liquid nozzle 41 and is discharged from the chemical liquid nozzle 41.

[0020] The rinse liquid supply system has a rinse liquid nozzle 45 that discharges a rinse liquid downward toward the upper surface of the substrate S held on the spin chuck 3. The rinse liquid nozzle 45 is disposed in the chamber 2. The rinse liquid supply system may also include a nozzle moving unit that moves the rinse liquid nozzle 45 between the processing position and the retracted position.

[0021] The rinse liquid nozzle 45 is connected to a rinse liquid supply source (not shown) that supplies the rinse liquid via a pipe 46. When a valve 62 provided in the fluid box 6 is opened, the rinse liquid is sent to the rinse liquid nozzle 45 and discharged from the rinse liquid nozzle 45. The rinse liquid is, for example, pure water (deionized water). The rinse liquid is not limited to pure water, but may also be any of carbonated water, electrolytic ionized water, hydrogen water, ozone water, and hydrochloric acid water with a diluted concentration (for example, about 10 to 100 ppm).

[0022] The cup 5 is disposed within the chamber 2. The cup 5 has a cylindrical inclined portion 51 extending obliquely upward toward the rotation axis A1, a cylindrical guide portion 52 extending downward from the lower end (outer end) of the inclined portion 51, and a liquid receiving portion 53 forming an upwardly opening annular groove. The inclined portion 51 has an annular upper end with an inner diameter larger than that of the substrate S and the spin base 31. The upper end of the inclined portion 51 corresponds to the upper end of the cup 5. The upper end of the cup 5 surrounds the substrate S and the spin base 31 in a plan view. When the processing liquid is supplied to the substrate S, the upper end of the cup 5 is positioned above the substrate S. Processing liquid such as the chemical liquid and the rinse liquid splashed outward from the substrate S is received by the inclined portion 51 and then collected in the liquid receiving portion 53 by the guide portion 52. The chemical liquid and the like are then discharged via a pipe 54. In other words, in this embodiment, the pipe 54 corresponds to an example of a "liquid drainage pipe" in the present invention.

[0023] The chemical liquid supply pipe 44, the rinse liquid supply pipe 46, and the drain pipe 54 pass through the interior of the fluid box 6 and are connected to a chemical liquid supply source, a rinse liquid supply source, and a drain tank (not shown), respectively. Inside the fluid box 6, valves 61 and 62 are inserted into the pipes 44 and 46, respectively. While the valve 61 is opened in response to a command from the control unit 7, which controls the entire apparatus, the chemical liquid is sent to the chemical liquid nozzle 41 and supplied from the chemical liquid nozzle 41 to the upper surface of the substrate S. This causes the chemical liquid components in the chemical liquid to be applied to the upper surface of the substrate S, thereby performing a predetermined substrate processing such as etching. Following the chemical liquid supply, while the valve 62 is opened in response to a command from the control unit 7, the rinse liquid is sent to the rinse liquid nozzle 45 and supplied from the rinse liquid nozzle 45 to the upper surface of the substrate S. This performs the rinse processing, and the amount of the chemical liquid components remaining on the upper surface of the substrate S decreases over time from the start of the rinse liquid supply. When the chemical liquid components are gone, the substrate processing is completely stopped. Therefore, by monitoring the amounts of chemical components while reproducing such chemical supply and rinse liquid supply at a position away from the upper surface of the substrate S, it becomes possible to estimate the progress of the process on the upper surface of the substrate S. Therefore, in this embodiment, an information acquisition device 8 having the above-mentioned monitoring function is installed in the fluid box 6.

[0024] Fig. 3 is a perspective view showing one embodiment of an information acquisition device according to the present invention. Figs. 4A and 4B are diagrams schematically showing the cross-sectional structure and operation of the information acquisition device shown in Fig. 3. In these figures, the direction in which fluids such as chemical solutions and rinse solutions flow within the flow cell of the information acquisition device is referred to as the "X direction," the horizontal direction from the right to the left in each figure is referred to as the "+X direction," and the opposite direction is referred to as the "-X direction." The horizontal direction perpendicular to the X direction is referred to as the "Y direction," and the vertical direction is referred to as the "Z direction."

[0025] The information acquisition device 8 includes a flow cell 804 having a flow path 802 for flowing a fluid, and a total reflection measurement unit 806 that measures information about a specific substance (in this embodiment, a chemical component contained in the chemical solution) present in the flow path 802. The flow cell 804 includes a cell portion 808 extending in the X direction and a transparent member 810 having the same composition as the substrate S. The cell portion 808 has an inlet 812 for introducing a fluid on its side surface facing the (−X) direction, and an outlet 814 for discharging the fluid on its side surface facing the (+X) direction. The center of the cell portion 808 cooperates with the transparent member 810 to form part of the flow path 802 extending from the inlet 812 to the outlet 814. That is, as shown in FIGS. 4A and 4B , an opening 816 is provided in the lower center of the cell portion 808 (hereinafter referred to as the "lower center cell"). The transparent member 810 is attached to the lower center cell portion so as to cover the opening 816 from below. Furthermore, an adjustment unit 818 is attached to the upper central portion of cell unit 808 (hereinafter referred to as the "cell upper central portion") so as to face transparent member 810. Therefore, in the central portion of cell unit 808, a central flow path region 820 is formed between adjustment unit 818 and transparent member 810, and a fluid introduced from inlet 812 is guided to outlet 814 via central flow path region 820. Furthermore, a pair of guide parts 822 are provided that hang down from the cell upper central portion toward transparent member 810, thereby forming a recess 824 at the cell upper central portion so as to retreat vertically upward from flow path 802.

[0026] The adjustment unit 818 includes a movable body 826 that is movable in the vertical direction Z while being guided by a pair of guide members 822, and a positioning block 828 that positions the movable body 826 in the vertical direction Z. As shown in FIGS. 4A and 4B , the movable body 826 includes a facing portion 830 that is movable in the vertical direction Z within the recess 824 with its lower surface facing the transparent member 810, and an upright portion 832 that stands vertically upward from the facing portion 830. The lower surface of the facing portion 830 faces the flow path 802, and the upper end of the upright portion 832 protrudes vertically upward from the upper center of the cell through a through-hole provided in the upper center of the cell. Therefore, for example, when an operator moves the upright portion 832 in the vertical direction Z, the distance from the upper surface of the transparent member 810 to the lower surface of the facing portion 830 (corresponding to the "flow path height" described later) changes. As a result, the cross-sectional area of ​​the flow path perpendicular to the fluid flow direction, i.e., the direction X, is adjusted.

[0027] To facilitate smooth adjustment of the cross-sectional area, in this embodiment, the positioning block 828 includes two hollow spacers 834, one connecting plate 836, two bolts 838, and two nuts 840. The two hollow spacers 834 are placed on the upper surface of the cell unit 808, sandwiching the upright portion 832 in the X direction. The upright portion 832 is inserted through a through-hole provided in the center of the hollow spacers 834, and the connecting plate 836 is positioned so as to span the upper end of the upright portion 832. The bolt 838 is inserted through a through-hole provided on the (-X) direction side of the hollow spacers 834 and the hollow spacer 834 on the (-X) direction side, and is screwed into the cell unit 808. The (+X) direction side is also finished in the same way. As a result, the hollow spacers 834 and the connecting plate 836 are fixed to the cell unit 808 in a gate-like shape. Furthermore, the upper end of the standing portion 832 is connected to the connecting plate 836 using two nuts 840. A male thread is formed on the upper end of the standing portion 832, and it is possible to adjust the positions of the nut 840 that screws onto the male thread below the connecting plate 836 and the nut 840 that screws onto the male thread above the connecting plate 836. In other words, the position of the movable body 826 can be changed by changing the height position of the movable body 826 in the vertical direction Z. Note that the configuration of the adjustment unit 818 is not limited to that described above, and a height adjustment mechanism that uses a motor, for example, may be used.

[0028] Returning to FIG. 2 , the description of the configuration of the substrate processing apparatus 1 will be continued. The inlet 812 of the information acquisition device 8 is connected to a pipe 63 branching from the pipe 44 between the valve 61 and the chemical nozzle 41. A valve 64 is inserted in this pipe 63. The pipe 46 branches between the valve 62 and the rinse liquid nozzle 45, and this branched pipe 65 is connected to the pipe 63 between the valve 64 and the branching position of the pipe 63 from the pipe 44. The pipe 63 branches between the valve 64 and the inlet 812, and this branched pipe 66 is connected to a nitrogen gas supply source. A valve 67 is inserted in the pipe 66. Therefore, in the fluid box 6, the valves 61, 62, 64, and 67 can be individually opened and closed in response to opening and closing commands from the control unit 7, thereby switching the supply modes of the chemical liquid, rinse liquid, and nitrogen gas. An overview of this is shown in the following table.

[0029]

[0030] In the conventional apparatus, the supply mode is substantially the same as that of switching position PS2 in Table 1, i.e., the chemical solution is supplied only to the upper surface of substrate S, and then the supply mode is substantially the same as that of switching position PS4, i.e., the rinse solution is supplied only to the upper surface of substrate S. This makes it impossible to monitor the processing status and surface condition of substrate S. In contrast, in this embodiment, after performing chemical processing at switching position PS3, switching to switching position PS5 allows rinsing processing to be performed. In this case, the same processing as the chemical processing and rinsing processing performed on the upper surface of substrate S is performed in flow cell 804 of information acquisition device 8. Therefore, by measuring the chemical components on and near the upper surface of transparent member 810 as specific substances using total reflection measurement unit 806, which will be described below, it is possible to monitor the chemical processing and rinsing processing on the upper surface of substrate S and estimate the processing status and surface condition. Furthermore, by switching between switching positions PS6 and PS8 by control unit 7, nitrogen purging of flow cell 804 is performed, making it possible to remove residue from flow cell 804.

[0031] In addition, reference numeral 68 in FIG. 2 denotes a discharge pipe that connects the discharge port 814 of the information acquisition device 8 to the pipe 54, and reference numeral 842 denotes an O-ring for preventing fluid from leaking from the flow cell 804.

[0032] Next, the configuration and operation of the total reflection measuring unit 806 will be described with reference to FIGS. 3, 4A, 4B, and 5. FIG.

[0033] FIG. 5 is a diagram schematically illustrating the configuration and operation of the total reflection measurement unit 806. The total reflection measurement unit 806 acquires information about the concentration of a specific substance based on information about the absorption spectrum of the specific substance that absorbs evanescent light that seeps out from the top surface of the transparent member 810 by being totally reflected at or near the top surface of the transparent member 810, which has the same composition as the substrate S. As shown in FIGS. 4A and 4B , the total reflection measurement unit 806 includes a light-projecting unit 844, a prism 846, and a light-receiving unit 848. The light-projecting unit 844 has a laser light source that generates laser light in wavelength ranges corresponding to both the transparent member 810 and the specific substance (chemical solution component). Here, a case where the substrate S and the transparent member 810 are silicon wafers will be described.

[0034] The wavelength band transmitted through the silicon wafer is 1.2 μm to 6 μm, and this wavelength band preferably includes the absorption wavelength band of the chemical solution components. In other words, the transparent member 810 must be transparent to the light emitted from the light-emitting unit 844 in a wavelength range that includes the absorption spectrum of the specific substance. Therefore, in this embodiment, the light-emitting unit 844 uses a directional infrared laser as its light source. The laser light L0 emitted from the light-emitting surface of the light-emitting unit 844 is incident on the transparent member 810 via a prism 846. The prism 846 guides the laser light L0 to a lower surface region on the (−X) direction side of the lower surface of the transparent member 810, causing it to enter the interior of the transparent member 810. After the laser light L0 enters the transparent member 810, the prism 846 adjusts the path of the laser light L0 near the lower surface region on the (−X) direction side so that the laser light L1 travels while undergoing total reflection within the transparent member 810. Furthermore, the prism 846 adjusts the path of the laser light L0 after incidence so that the laser light L1 travels in the (+X) direction while undergoing total reflection within the transparent member 810. In other words, the prism 846 functions to stably guide the laser light L0 into the transparent member 810 while ensuring an angle θ that is equal to or greater than the total reflection angle with respect to the direction Dv (the direction of the dashed line in the figure) perpendicular to both main surfaces (top and bottom surfaces) of the transparent member 810, which is necessary for the laser light L0 to be totally reflected by the upper and lower surfaces of the transparent member 810. Note that the external shape and type of the prism 846 are arbitrary as long as they can achieve this function; for example, a triangular prism may be used. Furthermore, in this embodiment, the laser light is configured to travel within the transparent member 810 parallel to the flow direction X of the fluid (chemical solution and rinse liquid). However, the laser light may be configured to travel in any direction as long as the direction is parallel to the upper and lower surfaces of the transparent member 810.

[0035] Furthermore, the distance d1 between transparent member 810 and prism 846 is set to be equal to or less than the diffraction limit of laser light L0. For example, if the center wavelength λ of laser light L0 and the angle θ are 3.4 μm and 60°, respectively, and the optical distance that can maintain the efficiency of capturing laser light L0 in the gap between prism 846 and transparent member 810 is λ / 8, then the distance d1 should satisfy the following inequality: d1<λ / 8×cos θ=212.5 nm.

[0036] As shown in FIG. 5 , laser light L0 from light projector 844 passes through prism 846 and the lower surface of transparent member 810 in this order, and is irradiated as laser light L1 onto the interior of transparent member 810. Thus, laser light L1 incident on the interior of transparent member 810 is irradiated onto the upper surface of transparent member 810 via the lower surface at the angle θ relative to the direction Dv. Laser light L1 is totally reflected at irradiation position Pf1 (the boundary between the upper surface of transparent member 810 and the fluid flowing through central flow path region 820). Furthermore, because the refractive index of the fluid is lower than that of transparent member 810, evanescent light Lef1 seeps out from the upper surface of transparent member 810 toward the fluid at the total reflection position. After evanescent light Lef1 is generated, laser light L1a travels through the interior of transparent member 810 in the (+X) direction due to total reflection at irradiation position Pf1, and is irradiated onto the lower surface of transparent member 810 at the angle θ. At this irradiation position Pb1 (the boundary position between the lower surface of the transparent member 810 and the air layer), the laser light L1a is totally reflected, and evanescent light Leb1 seeps out from the lower surface of the transparent member 810 toward the air layer. After the evanescent light Leb1 is generated, the laser light L1b travels in the (+X) direction inside the transparent member 810 due to total reflection at the irradiation position Pb1 and is irradiated onto the upper surface of the transparent member 810 at the angle θ. This total reflection is repeated, and multiple evanescent light beams Lef1, Lef2, ... are generated on the upper surface of the transparent member 810. These spots of evanescent light beams Lef1, Lef2, ... are formed at a constant interval W in the radial direction D. For example, as shown in FIG. 3 , if a chemical solution component adheres to the upper surface of the transparent member 810 at the irradiation position Pf3, the chemical solution component absorbs the evanescent light Lef3. Furthermore, the intensity of the evanescent light attenuates to 1 / e several hundred nm from the surface of the transparent member 810, and exists as a local field that is enhanced to a maximum of approximately four times the incident light intensity, a so-called surface enhancement effect, which allows even nano-sized components of the drug solution to be efficiently absorbed.

[0037] The laser light thus passing through while being totally reflected within the transparent member 810 is received by the light receiving unit 848, which obtains information according to the amount of received light, that is, information about the absorption spectrum of the specific substance that absorbed the evanescent light, and a signal containing this information is sent from the light receiving unit 848 to the control unit 7. Upon receiving this information, the control unit 7 can determine the concentration of the specific substance in the fluid flowing inside the flow cell 804, the remaining state of the specific substance on the upper surface of the transparent member 810 (residual chemical concentration), etc.

[0038] The control unit 7 is configured by a computer having a CPU (Central Processing Unit), RAM (Random Access Memory), etc., and controls each unit of the substrate processing apparatus 1 as follows in accordance with programs stored in a storage unit (not shown), thereby performing chemical processing and rinsing processing. In this embodiment, in parallel with the chemical processing and rinsing processing, an information acquisition device 8 provided outside the chamber 2 measures the residual chemical concentration on the upper surface of the substrate S. Furthermore, the flow rate of the fluid in the flow cell 804 is controlled according to various conditions for the chemical processing and rinsing processing, i.e., so-called process conditions. The operation of the substrate processing apparatus 1 will now be described with reference to FIGS. 6 to 8.

[0039] Fig. 6 is a flowchart showing the operation of the substrate processing apparatus shown in Fig. 2. The control unit 7 acquires the process conditions to be executed by the substrate processing apparatus 1 (step S1), determines the flow path height (i.e., the distance from the upper surface of the transparent member 810 to the opposing portion 830 of the movable body 826) that is suitable for the process conditions, and notifies the operator. Here, the technical significance of this will be explained with reference to Figs. 7 and 8 before explaining the chemical processing and rinsing processing.

[0040] FIG. 7 is a diagram showing the change in flow rate of the chemical solution with changes in flow channel height and the flow rate dependency of the concentration value when the concentration of a specific substance is measured by the information acquisition device in parallel with the chemical solution treatment. When the switching position PS3 in Table 1 is set, the information acquisition device 8 performs concentration measurement of the specific substance in parallel with the chemical solution treatment. In this case, for example, when the flow channel height is relatively large as shown in FIG. 4A , the cross-sectional area of ​​the flow channel 802 perpendicular to the flow direction of the chemical solution, i.e., direction X, in the central flow channel region 820 increases, and the flow rate of the chemical solution decreases. Therefore, the concentration value measured by the information acquisition device 8 (hereinafter referred to as the "monitoring concentration value") gradually increases from the timing Tcs when the chemical solution treatment starts and saturates at the timing Tce after a relatively long time has elapsed. In contrast, when the flow channel height is relatively small as shown in FIG. 4B , the cross-sectional area of ​​the flow channel 802 perpendicular to the flow direction of the chemical solution, i.e., direction X, in the central flow channel region 820 decreases, and the flow rate of the chemical solution increases. Therefore, the monitoring concentration value increases rapidly from the timing Tcs when the chemical treatment starts and saturates at the timing Tce after a relatively short time has passed. By referring to the monitoring concentration value, it is possible to estimate the status of the chemical treatment and the surface condition on the upper surface of the substrate S, but if the flow velocity of the chemical liquid on the upper surface of the substrate S differs significantly from the flow velocity of the chemical liquid in the information acquisition device 8, the estimation accuracy may decrease.

[0041] FIG. 8 is a diagram schematically illustrating the change in flow rate of the chemical solution with a change in flow channel height and the flow rate dependency of the concentration value when the concentration of a specific substance is measured by the information acquisition device in parallel with the rinse process. When the switching position PS5 in Table 1 is set, the information acquisition device 8 performs concentration measurement of the specific substance in parallel with the rinse process. In this case, for example, when the flow channel height is relatively large as shown in FIG. 4A , the cross-sectional area of ​​the flow channel 802 in the central flow channel region 820 increases, and the flow rate of the rinse solution decreases. Therefore, the monitored concentration value gradually decreases from the start time Trs of the rinse process and saturates at the time Tre after a relatively long time has elapsed. In contrast, for example, when the flow channel height is relatively small as shown in FIG. 4B , the cross-sectional area of ​​the flow channel 802 perpendicular to the flow direction of the rinse solution, i.e., direction X, in the central flow channel region 820 is small, and the flow rate of the rinse solution increases. Therefore, the monitored concentration value rapidly decreases from the start time Tcs of the rinse process and saturates at the time Tre after a relatively short time has elapsed. It is possible to estimate the status of the rinse process and the surface condition on the upper surface of the substrate S by referring to the monitoring concentration value, but if there is a large difference between the flow rate of the rinse liquid on the upper surface of the substrate S and the flow rate of the rinse liquid in the information acquisition device 8, the accuracy of estimating the end of the rinse process may decrease.

[0042] As described above, in order to accurately estimate the status of the chemical processing and rinsing processing of the substrate S based on the monitored concentration values, it is preferable to derive a flow path height that is compatible with the process conditions and then match it. Note that, if the flow rates of the fluids in the chemical processing and rinsing processing are different, it is desirable to adjust the flow path height to be compatible with one of the process conditions. For example, if priority is given to monitoring the completion of the rinsing processing, it is preferable to match the flow path height to the process conditions for the rinsing processing.

[0043] In step S2, when the operator confirms that the channel height has been adjusted to suit the process conditions, the control unit 7 issues a loading request for the substrate S to the substrate transport robot 111. In response to this, the substrate S is placed on the spin chuck 3. Subsequently, the chuck pins 32 hold the substrate S, and the substrate transport robot 111 retreats from the substrate processing apparatus 1 (step S3).

[0044] When preparation for chemical treatment is thus completed, the control unit 7 issues a movement command to the nozzle movement unit 42, causing the chemical nozzle 41 to move to the treatment position (the position indicated by the solid line in FIG. 2 ). The control unit 7 then starts rotation of the spin motor 34 of the spin chuck 3 holding the substrate S, and then switches the valves 61, 62, 64, and 65 from switching position PS1 to switching position PS3. This causes the chemical nozzle 41 to eject the chemical toward the upper surface of the substrate S, thereby starting chemical treatment (step S4). In this embodiment, the chemical is sent to the information acquisition device 8 in parallel with the chemical treatment, and a monitoring concentration value is measured as an example of the "information about the specific substance" of the present invention and sent to the control unit 7 (step S5).

[0045] The control unit 7 receives the monitoring concentration values ​​and estimates the surface state of the substrate S during the chemical processing based on the monitoring concentration values ​​(step S6). The acquisition of the monitoring concentration values ​​(step S5) and the estimation of the surface state (step S6) are repeated until the control unit 7 determines that the chemical processing is completed ("YES" in step S7).

[0046] When the chemical solution processing is completed, the control unit 7 issues a movement command to the nozzle movement unit 42, causing the chemical solution nozzle 41 to move from the processing position (the position indicated by the solid line in FIG. 2 ) to the retracted position (the position indicated by the dotted line in FIG. 2 ). Subsequently, the control unit 7 switches the valves 61, 62, 64, and 65 to the switching position PS4. As a result, the rinse solution is ejected from the rinse solution nozzle 45 toward the upper surface of the substrate S, and the rinse process begins (step S8). In this embodiment, the rinse solution is sent to the information acquisition device 8 in parallel with the rinse process, and the rinse solution is supplied to the upper surface of the transparent member 810 on which the chemical solution remains. As a result, while the transparent member 810 is subjected to a rinse process similar to the rinse process performed on the substrate S, the monitored concentration value is measured as an example of the "information about the specific substance" of the present invention and sent to the control unit 7 (step S9).

[0047] The control unit 7, having received the monitoring concentration values, estimates the surface state of the substrate S during the rinsing process, particularly the progress of the rinsing process, based on the monitoring concentration values ​​(step S10). The acquisition of the monitoring concentration values ​​(step S9) and the estimation of the surface state (step S10) are repeated until the control unit 7 determines that the rinsing process has been completed ("YES" in step S11). This allows the control unit 7 to estimate the progress of the rinsing process on the substrate S with high accuracy from the monitoring concentration values. Furthermore, it is possible to accurately estimate the end timing of the rinsing process. As a result, it is possible to reduce the supply of excessive rinsing liquid and reduce the environmental impact.

[0048] When the rinsing process is completed, the control unit 7 switches the valves 61, 62, 64, and 65 to the switching position PS1, thereby stopping the supply of the rinsing liquid to the substrate S and the information acquisition device 8. Subsequently, the control unit 7 issues a high-speed rotation command to the spin motor 34 to spin-dry the substrate S (step S12).

[0049] Thereafter, the control unit 7 issues a rotation stop command to the spin motor 34 to stop the rotation of the substrate S. Furthermore, the control unit 7 requests the substrate transport robot 111 to unload the substrate S, and the processed substrate S is unloaded from the substrate processing apparatus 1 (step S13).

[0050] As described above, in this embodiment, the concentration of a specific substance present in the flow path 802, i.e., the monitoring concentration value, can be measured while controlling the flow rate of the fluid (chemical and rinse liquid) in the flow path 802 of the flow cell 804. In particular, because the monitoring concentration value is measured in parallel with the chemical treatment and rinse treatment at a flow path height that is suited to the process conditions, the surface condition of the substrate S can be estimated with high accuracy from the monitoring concentration value. This makes it possible to suitably control the chemical treatment and rinse treatment, and to reduce waste of the chemical and rinse liquid. Furthermore, the environmental load can be reduced.

[0051] In the above-described embodiment, the upper surface of the transparent member 810 corresponds to an example of the "flow path side main surface" of the present invention. Also, the chemical liquid supply system and the rinse liquid supply system correspond to an example of the "fluid supply system" of the present invention.

[0052] 9 is a diagram showing the configuration of a second embodiment of a substrate processing apparatus equipped with an information acquisition device according to the present invention. The second embodiment differs significantly from the first embodiment (FIG. 2) in the location of the information acquisition device 8. That is, in the first embodiment, a portion of the fluid (chemical liquid, rinse liquid) is extracted from the fluid supply system, and the monitoring concentration value is measured. In contrast, in the second embodiment, a portion of the waste liquid (chemical liquid, rinse liquid, or a mixture of both) is extracted from the fluid discharge system, which discharges the fluid collected in the liquid receiver 53, and the monitoring concentration value is measured.

[0053] 9 , in the second embodiment, a pipe 69 branching from the pipe 54 is connected to an inlet 812 of the information acquisition device 8. A valve 70 is inserted in this pipe 69. Therefore, when the valve 70 is opened in response to an open command from the control unit 7 while the valve 67 is closed, a portion of the fluid flowing through the pipe 54 is introduced into the information acquisition device 8 via the pipe 69. For example, when the valve 70 is opened in parallel with the rinsing process, it becomes possible to estimate the surface state of the substrate S during the rinsing process based on the monitoring concentration value measured during the rinsing process, as in the first embodiment.

[0054] In the second embodiment, the chemical liquid, the rinse liquid, and the mixture of the two are discharged through the pipe 54 without being separated. This makes it difficult to recover the chemical liquid for recycling. Therefore, as shown in Fig. 10, the chemical liquid, the rinse liquid, and the mixture of the chemical liquid and the rinse liquid may be recovered separately, and such a substrate processing apparatus 1 may be equipped with an information acquisition device 8 (third embodiment).

[0055] FIG. 10 is a diagram showing the configuration of a third embodiment of a substrate processing apparatus equipped with an information acquisition device according to the present invention. The third embodiment differs significantly from the second embodiment in that the cup 5 is configured similarly to the double-cup structure described, for example, in Japanese Patent Application Laid-Open No. 2003-264167. That is, in the third embodiment, during chemical processing, the chemical is collected in a dedicated chemical cup 5A and recovered via a chemical recovery pipe 54A. Meanwhile, during rinsing processing, a mixture of the chemical and the rinse liquid and the rinse liquid are collected in a dedicated rinsing cup 5B and discharged via a drainage pipe 54B. Furthermore, in the third embodiment, the drainage pipe 54B has the same configuration as in the second embodiment. That is, as shown in FIG. 10 , a pipe 69 branching from the pipe 54B is connected to an inlet 812 of the information acquisition device 8. When the valve 70 is opened in response to an open command from the control unit 7 while the valve 67 is closed, a portion of the fluid flowing through the pipe 54B is introduced into the information acquisition device 8 via the pipe 69. By opening the valve 70 in parallel with the rinsing process, it becomes possible to estimate the surface condition of the substrate S during the rinsing process based on the monitoring concentration values ​​measured during the rinsing process, as in the first and second embodiments.

[0056] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the above embodiment, the channel height is manually changed by an operator. However, the channel height may be changed using a motor, actuator, or the like. In this case, the control unit 7 may determine the optimal channel height during the chemical processing based on the process conditions before the chemical processing, adjust the channel height to the determined channel height by controlling a motor or the like, and measure the monitoring concentration value at the adjusted channel height in parallel with the chemical processing. The same applies to the rinse processing. That is, the control unit 7 may determine the optimal channel height during the rinse processing based on the process conditions after the chemical processing and before the rinse processing, adjust the channel height to the determined channel height by controlling a motor or the like, and measure the monitoring concentration value at the adjusted channel height in parallel with the rinse processing. Furthermore, in the above embodiment, the laser light L0 is incident on the transparent member 810 through the prism 846. However, the edge of the transparent member 810 may be beveled so that the laser light L0 is directly incident on the beveled portion.

[0057] Furthermore, in the above embodiment, an information acquisition device 8 applicable to a substrate processing apparatus 1 that performs chemical processing and rinsing processing in this order was described, but the information acquisition device and information acquisition method of the present invention can also be applied to other substrate processing apparatuses or apparatuses different from substrate processing apparatuses.

[0058] Furthermore, in the above embodiment, the information acquisition device 8 monitors the surface condition of the substrate S while the substrate S is being subjected to a chemical treatment or rinsing treatment, so the composition of the transparent member 810 is limited to the same as that of the substrate S. If the information acquisition device 8 is limited to measuring the concentration of a specific substance in a fluid, the transparent member 810 can be made of a material that is transparent to a wavelength range that includes the absorption spectrum of the specific substance. While the invention has been described above with reference to specific examples, this description is not intended to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as other embodiments of the present invention, will be apparent to those skilled in the art upon reference to the description of the invention. Therefore, the appended claims are intended to include such modifications or embodiments within the true scope of the invention.

[0059] The present invention can be applied to general information acquisition techniques for measuring information about a specific substance present in a flow channel provided in a flow cell while a fluid is flowing through the flow channel.

[0060] DESCRIPTION OF SYMBOLS 1... Substrate processing apparatus 7... Control unit 8... Information acquisition device 802... Flow path 804... Flow cell 806... Total reflection measurement unit 808... Cell unit 810... Transparent member 812... Inlet 814... Outlet 816... Opening 818... Adjustment unit 820... Central flow path region 824... Recess 826... Movable body 828... Positioning block S... Substrate

Claims

1. An information acquisition device comprising: a flow cell having a flow path for flowing a fluid; and a total reflection measurement unit that measures information about a specific substance present in the flow path through which the fluid is flowing, wherein the flow cell comprises: a cell unit having an inlet for introducing the fluid and an outlet for discharging the fluid, extending from the inlet to the outlet to form a part of the flow path; and a transparent member that is transparent to a wavelength range that includes the absorption spectrum of the specific substance, and is provided in the cell unit between the inlet and the outlet to close an opening provided in the cell unit, thereby forming the flow path in cooperation with the cell unit; wherein the total reflection measurement unit comprises: a light projecting unit that irradiates the transparent member with light having directionality in the wavelength range so that the light is totally reflected inside the transparent member; and a light receiving unit that receives light that has been totally reflected by the transparent member and has emerged from the transparent member; and wherein the cell unit has an adjustment unit that adjusts the cross-sectional area of ​​the flow path perpendicular to the flow direction of the fluid.

2. An information acquisition device as described in claim 1, wherein the cell section has a recess that is disposed opposite the transparent member across the flow path and is recessed from the flow path in a first direction perpendicular to the flow direction, and the adjustment section has a movable body that is disposed within the recess so as to be movable in the first direction with its tip face facing the transparent member, and a positioning block that positions the movable body in the first direction, and the cross-sectional area of ​​the flow path is adjusted by changing the distance from the transparent member to the tip face of the movable body in the first direction by changing the position of the movable body using the positioning block.

3. An information acquisition device according to claim 1 or 2, wherein the transparent member has a flow path-side main surface facing the flow path through the opening, and the total reflection measurement unit measures the concentration of the specific substance on the flow path-side main surface and in the vicinity of the flow path-side main surface as the information.

4. An information acquisition device as described in claim 1, wherein the flow cell is arranged in a fluid supply system that supplies a chemical solution containing the specific substance to the substrate for chemical treatment of the substrate, and a portion of the chemical solution is flowed into the flow path as the fluid, and the total reflection measurement unit measures the concentration of the specific substance as the information.

5. An information acquisition device as described in claim 1, wherein the flow cell is arranged in a fluid supply system that supplies to the substrate, in this order, a chemical solution containing the specific substance for treating the substrate and a rinse solution for rinsing the substrate that has been chemically treated with the chemical solution, and flows a portion of the chemical solution and a portion of the rinse solution as the fluid through the flow path, and the total reflection measurement unit measures the concentration of the specific substance as the information.

6. An information acquisition device according to claim 1, wherein the flow cell is arranged in a fluid discharge system that discharges a chemical solution containing the specific substance used to chemically process a substrate and a rinse solution used to rinse the chemically processed substrate, and at least a portion of the chemical solution and at least a portion of the rinse solution are flowed as the fluid, and the total reflection measurement unit measures the concentration of the specific substance as the information.

7. An information acquisition device according to claim 1, wherein the flow cell is arranged in a fluid discharge system that discharges, via different drainage pipes, a chemical solution containing the specific substance used to chemically treat a substrate and a rinse solution used to rinse the chemically treated substrate, and at least a portion of the rinse solution is flowed as the fluid, and the total reflection measurement unit measures the concentration of the specific substance in the rinse solution as the information.

8. An information acquisition device according to any one of claims 4 to 7, wherein the transparent member is made of the same composition as the substrate.

9. A method for acquiring information, comprising the steps of: preparing a flow cell having a cell portion having an inlet for introducing a fluid and an outlet for discharging the fluid, the cell portion extending from the inlet to the outlet to form a part of a flow path; and a transparent member that is transparent to a wavelength range that includes the absorption spectrum of a specific substance and that is provided in the cell portion so as to close an opening provided in the cell portion between the inlet and the outlet, thereby cooperating with the cell portion to form the flow path; flowing the fluid through the flow path of the flow cell; irradiating the transparent member with light having directionality in the wavelength range so that it is totally reflected inside the transparent member, and receiving the light that has been totally reflected by the transparent member and then exits the transparent member to measure information about the specific substance present in the flow path through which the fluid is flowing; and adjusting the cross-sectional area of ​​the flow path perpendicular to the flow direction of the fluid before measuring the information.

Images