Substrate processing apparatus and film thickness estimation method

Abstract

The present disclosure describes a substrate treatment device and a film thickness estimation method that are capable of accurately estimating the film thickness that changes every minute during etching processing even under a disturbed environment.　The substrate treatment device includes a holding portion, a supply portion, an optical sensor, and a control unit. The control unit is configured to execute first treatment for supplying an etching solution to a surface of a substrate held by the holding portion, second treatment for acquiring a change in the intensity of reflected light that the optical sensor has received and that comes from an irradiation section, while the etching solution is being supplied to the surface of the substrate, third treatment for removing a disturbance component generated due to an impact of a disturbance inducer located above the substrate, from intensity change data indicating a change in the intensity of the reflected light acquired in the second treatment, to generate correction data, and fourth treatment for estimating the film thickness of a film during etching processing on the basis of the correction data.

Description

Technical Field

[0001] The present disclosure relates to a substrate processing apparatus and a film thickness estimation method.

Background Art

[0002] Currently, in manufacturing semiconductor devices by microfabricating a substrate (e.g., a semiconductor wafer), a substrate processing system that discharges various processing liquids onto the substrate to perform substrate processing is known. Patent Document 1 discloses a film thickness measurement method including a step of guiding light from a light source (halogen lamp) to the surface of a substrate through a lens, a mirror, etc., a step of receiving the reflected light from the surface of the substrate by a light receiving means, and a step of collectively calculating the film thickness of a thin film formed on the surface of the substrate based on information representing the two-dimensional spatial distribution of the amount of the reflected light.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure describes a substrate processing apparatus and a film thickness estimation method capable of accurately estimating a film thickness that changes moment by moment during an etching process even in an environment with disturbances.

Means for Solving the Problems

[0005] An example of a substrate processing apparatus includes a holding unit configured to hold a substrate on which a film is formed on its surface, a supply unit configured to supply an etching solution to the surface of the substrate, a photosensor configured to irradiate a predetermined wavelength of light toward an irradiation point set to overlap with the surface of the substrate held by the holding unit, and to receive the reflected light, and a control unit. The control unit is configured to perform a first process of controlling the supply unit to supply an etching solution to the surface of the substrate held by the holding unit, a second process of acquiring the change in the intensity of the reflected light from the irradiation point received by the photosensor while the etching solution is being supplied to the surface of the substrate, a third process of removing disturbance components caused by disturbance-inducing objects located above the substrate from the intensity change data showing the change in the intensity of the reflected light acquired in the second process, and generating correction data, and a fourth process of estimating the film thickness during the etching process based on the correction data. [Effects of the Invention]

[0006] According to the substrate processing apparatus and film thickness estimation method described herein, it is possible to accurately estimate the film thickness, which changes moment by moment during etching, even in a disturbed environment. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic plan view showing an example of a substrate processing system. [Figure 2] Figure 2 is a schematic side view showing an example of a liquid processing unit. [Figure 3] Figure 3 is a top view showing an example of the irradiation position by the light sensor. [Figure 4] Figure 4 is a block diagram showing an example of the main components of a substrate processing system. [Figure 5] Figure 5 shows an example of a model illustrating the relationship between film thickness and reflectivity. [Figure 6] Figure 6 shows an example of a model illustrating the relationship between film thickness and reflectivity. [Figure 7]Figure 7 shows an example of a model illustrating the relationship between film thickness and reflectivity. [Figure 8] Figure 8 is a schematic diagram showing an example of the controller's hardware configuration. [Figure 9] Figure 9 is a flowchart illustrating an example of the substrate processing procedure. [Figure 10] Figure 10 is a graph showing an example of intensity change data at a predetermined irradiation site. [Figure 11] Figure 11 is a graph showing an example of corrected data. [Figure 12] Figure 12 is a schematic side view showing another example of a liquid processing unit. [Figure 13] Figure 13 shows another example of a model illustrating the relationship between film thickness and reflectivity. [Modes for carrying out the invention]

[0008] In the following descriptions, the same reference numeral will be used for identical elements or elements with the same function, and redundant explanations will be omitted. Furthermore, in this specification, when referring to the top, bottom, right, and left of a figure, the direction of the reference numeral in the figure will be used as the reference.

[0009] [Configuration of the substrate processing system] First, with reference to Figure 1, a substrate processing system 1 (substrate processing apparatus) configured to process a substrate W will be described. The substrate processing system 1 comprises an input / output station 2, a processing station 3, and a controller Ctr (control unit). The input / output station 2 and the processing station 3 may be arranged in a single line horizontally, for example.

[0010] The substrate W may be disc-shaped, or it may be a plate shape other than circular, such as a polygon. The substrate W may have a notch in which a part is cut out. The notch may be, for example, a notch (groove such as U-shaped or V-shaped), or a straight section extending in a straight line (a so-called orientation flat). The substrate W may be, for example, a semiconductor substrate (silicon wafer), a glass substrate, a mask substrate, an FPD (Flat Panel Display) substrate, or various other types of substrates. The diameter of the substrate W may be, for example, about 200 mm to 450 mm.

[0011] As illustrated in Figure 2, a film F is formed on the upper surface Wa of the substrate W. The film F may be a thermal oxide film (Th-Ox) or a metal film. Examples of metal films include titanium nitride, silicon nitride (SiN), titanium oxide, titanium, tungsten, tantalum, tantalum nitride, aluminum, aluminum oxide, copper, ruthenium, zirconium oxide, and hafnium oxide. In this specification, "surface of the substrate W" refers to the outermost surface of the substrate W. That is, in the example in Figure 2 where a film F is formed on the upper surface Wa of the substrate W, "surface of the substrate W" refers to the upper surface Fa of the film F.

[0012] The loading / unloading station 2 includes a loading section 4 (acquisition section), a loading / unloading section 5, and a shelf unit 6. The loading section 4 includes a plurality of loading platforms (not shown) arranged in the width direction (vertical direction in Figure 1). Each loading platform is configured to accommodate a carrier 7. The carrier 7 is configured to house at least one substrate W in a sealed state. The carrier 7 includes an opening / closing door (not shown) for loading and unloading the substrate W.

[0013] The loading / unloading section 5 is located adjacent to the loading / unloading section 4 in the direction in which the loading / unloading station 2 and processing station 3 are aligned (left-right direction in Figure 1). The loading / unloading section 5 includes an opening / closing door (not shown) provided for the loading / unloading section 4. When the carrier 7 is placed on the loading / unloading section 4, both the opening / closing door of the carrier 7 and the opening / closing door of the loading / unloading section 5 are opened, creating communication between the inside of the loading / unloading section 5 and the inside of the carrier 7.

[0014] The loading / unloading unit 5 incorporates a transfer arm A1 and a shelf unit 6. The transfer arm A1 is configured to be capable of horizontal movement in the width direction of the loading / unloading unit 5, vertical movement in the vertical direction, and swivel movement around the vertical axis. The transfer arm A1 is configured to take out the substrate W from the carrier 7 and pass it to the shelf unit 6, and also to receive the substrate W from the shelf unit 6 and return it into the carrier 7. The shelf unit 6 is located near the processing station 3 and is configured to accommodate the substrate W.

[0015] The processing station 3 includes a transfer unit 8 and a plurality of liquid processing units U (substrate processing apparatuses). The transfer unit 8 extends horizontally, for example, in the direction (the left-right direction in FIG. 1) in which the loading / unloading station 2 and the processing station 3 are arranged side by side. The transfer unit 8 incorporates a transfer arm A2 (transfer unit). The transfer arm A2 is configured to be capable of horizontal movement in the longitudinal direction of the transfer unit 8, vertical movement in the vertical direction, and swivel movement around the vertical axis. The transfer arm A2 is configured to take out the substrate W from the shelf unit 6 and pass it to the liquid processing unit U, and also to receive the substrate W from the liquid processing unit U and return it into the shelf unit 6.

[0016] The plurality of liquid processing units U are arranged in a row along the longitudinal direction (the left-right direction in FIG. 1) on each of both sides of the transfer unit 8. The liquid processing unit U is configured to perform a predetermined process (for example, etching process, cleaning process, etc.) on the substrate W. Details of the liquid processing unit U will be described later.

[0017] The controller Ctr is configured to control the substrate processing system 1 partially or entirely. Details of the controller Ctr will be described later.

[0018] [Details of Liquid Processing Unit] Next, the liquid processing unit U will be described in detail with reference to Figures 2 to 4. As illustrated in Figure 2, the liquid processing unit U comprises a rotating holding unit 10 (holding unit), supply units 20 and 30, and a plurality of optical sensors 40.

[0019] The rotating and holding unit 10 includes a drive unit 11, a shaft 12, and a holding unit 13. The drive unit 11 operates based on an operation signal from the controller Ctr and is configured to rotate the shaft 12. The drive unit 11 may be a power source such as an electric motor.

[0020] The holding portion 13 is provided at the tip of the shaft 12. The holding portion 13 is configured to hold the lower surface Wb of the substrate W by suction, for example. That is, the rotating holding portion 10 may be configured to rotate the substrate W around a rotation center axis Ax perpendicular to the surface of the substrate W, while the substrate W is in a substantially horizontal position.

[0021] The supply unit 20 is configured to supply etching solution L1 to the surface of the substrate W. The etching solution L1 may be, for example, an acid-based solution, an alkaline-based solution, or an organic-based solution. Acid-based solutions may include, for example, SC-2 solution (a mixture of hydrochloric acid, hydrogen peroxide, and pure water), SPM (a mixture of sulfuric acid and hydrogen peroxide solution), HF solution (hydrofluoric acid), DHF solution (dilute hydrofluoric acid), HNO3+HF solution (a mixture of nitric acid and hydrofluoric acid), etc. Alkaline solutions may include, for example, SC-1 solution (a mixture of ammonia, hydrogen peroxide, and pure water), hydrogen peroxide solution, etc.

[0022] The supply unit 20 includes a liquid source 21, a pump 22, a valve 23, a nozzle 24 (disturbance inducer), piping 25, an arm 26 (disturbance inducer), and a drive source 27. The liquid source 21 is the source of the etching solution L1. The pump 22 operates based on an operating signal from the controller Ctr and is configured to send the etching solution L1 drawn from the liquid source 21 to the nozzle 24 via the piping 25 and valve 23.

[0023] Valve 23 operates based on an operating signal from controller Ctr and is configured to transition between an open state that allows fluid flow in piping 25 and a closed state that prevents fluid flow in piping 25. Nozzle 24 is positioned above the substrate W such that its discharge port faces the surface of the substrate W. Nozzle 24 is configured to discharge etching solution L1, which is sent from pump 22, from its discharge port toward the surface of the substrate W. Since the substrate W is rotated by the rotation holding unit 10, the etching solution L1 discharged onto the surface of the substrate W spreads from the center toward the periphery of the substrate W at a predetermined diffusion rate, and is then swept outward from the periphery of the substrate W (see Figure 4).

[0024] The piping 25 connects, in order from upstream, the liquid source 21, the pump 22, the valve 23, and the nozzle 24. The arm 26 holds the nozzle 24. A drive source 27 is connected to the arm 26. The drive source 27 operates based on an operation signal from the controller Ctr and is configured to move the arm 26 horizontally or vertically above the substrate W (see arrows Ar1 and Ar2 in Figure 2). Therefore, the etching solution L1 can be discharged not only to the center of the substrate W surface, but also to any position on the surface of the substrate W. For example, while the etching solution L1 is continuously being discharged from the nozzle 24, the nozzle 24 may move from the periphery to the center of the substrate W (so-called scan-in operation). Alternatively, while the etching solution L1 is continuously being discharged from the nozzle 24, the nozzle 24 may move from the center to the periphery of the substrate W (so-called scan-out operation).

[0025] The supply unit 30 is configured to supply rinsing solution L2 to the substrate W. Rinsing solution L2 is a liquid used to remove (wash away) etching solution L1 supplied to the surface of the substrate W, dissolving components of the film F by etching solution L1, etching residue, etc. Rinsing solution L2 may contain, for example, pure water (DIW), ozonated water, carbonated water (CO2 water), ammonia water, etc.

[0026] The supply unit 30 includes a liquid source 31, a pump 32, a valve 33, a nozzle 34, piping 35, an arm 36, and a drive source 37. The liquid source 31 is the source of the rinse liquid L2. The pump 32 operates based on an operating signal from the controller Ctr and is configured to send the rinse liquid L2 drawn from the liquid source 31 to the nozzle 34 via the piping 35 and the valve 33.

[0027] Valve 33 operates based on an operating signal from controller Ctr and is configured to transition between an open state that allows fluid flow in piping 35 and a closed state that prevents fluid flow in piping 35. Nozzle 34 is positioned above substrate W such that its discharge port faces the surface of the substrate W of the film F. Nozzle 34 is configured to discharge the rinse liquid L2 sent from pump 32 from its discharge port toward the surface of substrate W. Since substrate W is rotated by the rotation holding unit 10, the rinse liquid L2 discharged onto the surface of substrate W spreads from the center toward the periphery of substrate W at a predetermined diffusion rate and is then swept outward from the periphery of substrate W.

[0028] The piping 35 connects, in order from upstream, the liquid source 31, the pump 32, the valve 33, and the nozzle 34. The arm 36 holds the nozzle 34. A drive source 37 is connected to the arm 36. The drive source 37 operates based on an operation signal from the controller Ctr and is configured to move the arm 36 horizontally or vertically above the substrate W (see arrows Ar1 and Ar2 in Figure 2). Therefore, the rinse liquid L2 can be discharged not only to the center of the surface of the substrate W, but also to any position on the surface of the substrate W. For example, while the nozzle 34 is continuously discharging the rinse liquid L2, the nozzle 34 may move from the periphery to the center of the substrate W (so-called scan-in operation). Alternatively, while the nozzle 34 is continuously discharging the rinse liquid L2, the nozzle 34 may move from the center to the periphery of the substrate W (so-called scan-out operation).

[0029] Multiple light sensors 40 are arranged above the substrate W. Each of the multiple light sensors 40 includes an illuminating unit (not shown) and a light receiving unit (not shown). The illuminating unit operates based on an operation signal from the controller Ctr and is configured to irradiate light onto the surface of the substrate W while it is rotating with the rotation holding unit 10. The light receiving unit is configured to receive light reflected from the surface of the substrate W (reflected light) and transmit the intensity of the reflected light (hereinafter referred to as "reflection intensity") to the controller Ctr.

[0030] The optical sensor 40 may be, for example, a laser sensor, a photoelectric sensor, or a color sensor. If the optical sensor 40 is a laser sensor, the irradiation unit may use, for example, a red laser (wavelength: 655 nm), a green laser (wavelength: 532 nm), a blue laser (wavelength: 405 nm), or any other type of laser light.

[0031] The irradiating portion of the light sensor 40 may irradiate light downward along a direction perpendicular to the surface of the substrate W. The irradiating portion of the light sensor 40 may irradiate light onto the surface of the substrate W via a light-reflecting member (e.g., a mirror), and the light-receiving portion of the light sensor 40 may receive the reflected light via the mirror. In these cases, the irradiating portion and the light-receiving portion of the light sensor 40 may be located in the same housing or may be physically separated.

[0032] The irradiating portion of the light sensor 40 may irradiate light diagonally downward along a direction inclined with respect to the surface of the substrate W. In this case, the irradiating portion and the light receiving portion of the light sensor 40 may be physically separated, and the light irradiation point on the surface of the substrate W may be positioned between them.

[0033] The multiple light sensors 40 may include three light sensors 41 to 43, as illustrated in Figure 2. Each of the light sensors 41 to 43 is configured to emit light toward irradiation points P1 to P3, which are set to overlap with the surface of the substrate W held by the rotating holding unit 10, and to receive reflected light reflected from the irradiation points P1 to P3. Each of the irradiation points P1 to P3 is a fixed position and does not change even when the substrate W rotates.

[0034] The irradiation points P1 to P3 are set at different positions from each other, as illustrated in Figure 2. That is, the irradiation points P1 to P3 may be aligned from the center to the periphery of the substrate W. Specifically, irradiation point P2 may be located closer to the periphery of the substrate W than irradiation point P1, and irradiation point P3 may be located closer to the periphery of the substrate W than irradiation point P2. The irradiation points P1 to P3 may be aligned in a line in the radial direction of the substrate W, as illustrated in Figure 3(a). Alternatively, the irradiation points P1 to P3 may not be aligned in the radial direction of the substrate W, but may be offset in the circumferential direction of the substrate W, as illustrated in Figure 3(b). That is, irradiation points P1 and P2 do not have to lie on a straight line connecting irradiation point P3 and the center of the substrate W, irradiation points P2 and P3 do not have to lie on a straight line connecting irradiation point P1 and the center of the substrate W, and irradiation points P1 and P3 do not have to lie on a straight line connecting irradiation point P2 and the center of the substrate W.

[0035] The distances between the irradiation points P1 to P3 may be approximately equal or different. If the radius of the substrate W is approximately 150 mm, irradiation point P1 may be located approximately 50 mm from the center of the substrate W, irradiation point P2 may be located approximately 100 mm from the center of the substrate W, and irradiation point P3 may be located approximately 147 mm from the center of the substrate W.

[0036] [Controller Details] As illustrated in Figure 4, the controller Ctr has a reading unit M1, a storage unit M2, a processing unit M3, and an instruction unit M4 as functional modules. These functional modules are merely a convenient division of the controller Ctr's functions into multiple modules, and do not necessarily mean that the hardware constituting the controller Ctr is divided into such modules. Each functional module is not limited to being implemented by program execution, but may also be implemented by a dedicated electrical circuit (e.g., a logic circuit) or an integrated circuit (ASIC: Application Specific Integrated Circuit) that integrates these.

[0037] The reading unit M1 is configured to read a program from a computer-readable recording medium RM. The recording medium RM stores a program for operating each part of the substrate processing system 1, including the liquid processing unit U. The recording medium RM may be, for example, a semiconductor memory, an optical recording disk, a magnetic recording disk, or a magneto-optical recording disk. In the following description, each part of the substrate processing system 1 may include a rotating holding unit 10, supply units 20 and 30, and an optical sensor 40.

[0038] The storage unit M2 is configured to store various types of data. For example, the storage unit M2 may store programs read from the recording medium RM by the reading unit M1, setting data input from the operator via an external input device (not shown), etc. The storage unit M2 may also store reflection intensity data acquired by the optical sensor 40.

[0039] The memory unit M2 may store a model representing the relationship between the film thickness of the film F and its reflectivity. The method for generating this model is as follows, for example. First, the test substrate W (sample substrate) is held in the rotating holding unit 10. Next, the controller Ctr controls the rotating holding unit 10 to rotate the test substrate W while holding its back surface by suction. In this state, the controller Ctr controls the supply units 20 and 30 to sequentially supply etching solution L1 and rinsing solution L2 to the surface of the test substrate W, thereby etching the film F. Next, the film thickness of the etched film F is measured using a known film thickness measuring device. In addition, light is shone onto the etched film F using the optical sensor 40, and the reflected light is received by the optical sensor 40 to measure the reflectivity of the reflected light. Subsequently, the above process is performed on multiple test substrates W while varying the etching time, and the reflectivity for multiple different film thicknesses is obtained to create a model representing the relationship between the film thickness of the film F and its reflectivity.

[0040] Here, Figures 5 to 7 show examples of models. Figures 5(a) to 5(c) are examples of models showing the relationship between film thickness and reflectance at irradiation points P1 (50 mm), P2 (100 mm), and P3 (147 mm) when using a substrate W in which the film F is formed of titanium nitride. Figures 6(a) to 6(c) are examples of models showing the relationship between film thickness and reflectance at irradiation points P1 (50 mm), P2 (100 mm), and P3 (147 mm) when using a substrate W in which the film F is formed of silicon nitride (SiN). Figures 7(a) to 7(c) are examples of models showing the relationship between film thickness and reflectance at irradiation points P1 (50 mm), P2 (100 mm), and P3 (147 mm) when using a substrate W in which the film F is formed of a thermal oxide film (Th-Ox). The optical sensor 40 used in creating each model in Figures 5 to 7 was a laser sensor, and the wavelength of its laser light was 655 nm.

[0041] The processing unit M3 is configured to process various types of data. For example, the processing unit M3 may generate signals to operate various parts of the substrate processing system 1 based on the various types of data stored in the storage unit M2.

[0042] The instruction unit M4 is configured to transmit the operation signals generated in the processing unit M3 to each part of the substrate processing system 1.

[0043] The hardware of the controller Ctr may consist of, for example, one or more control computers. The controller Ctr may include circuit C1 as a hardware configuration, as shown in Figure 8. Circuit C1 may consist of electrical circuit elements. Circuit C1 may include, for example, a processor C2, memory C3, storage C4, driver C5, and input / output ports C6.

[0044] The processor C2 may be configured to implement each of the above-described functional modules by executing a program in cooperation with at least one of the memory C3 and storage C4 and performing signal input and output via the input / output port C6. The memory C3 and storage C4 may function as a storage unit M2. The driver C5 may be a circuit configured to drive each part of the board processing system 1. The input / output port C6 may be configured to mediate signal input and output between the driver C5 and each part of the board processing system 1.

[0045] The board processing system 1 may have one controller Ctr, or it may have a controller group (control unit) composed of multiple controllers Ctr. If the board processing system 1 has a controller group, each of the above functional modules may be realized by one controller Ctr, or by a combination of two or more controllers Ctr. If the controller Ctr is composed of multiple computers (circuit C1), each of the above functional modules may be realized by one computer (circuit C1), or by a combination of two or more computers (circuit C1). The controller Ctr may have multiple processors C2. In this case, each of the above functional modules may be realized by one processor C2, or by a combination of two or more processors C2.

[0046] [Substrate Processing Method] Next, with reference to Figures 9 to 11, a method for treating the substrate W with a processing solution will be described.

[0047] First, the carrier 7 is placed on the mounting platform of the mounting unit 4. The carrier 7 contains at least one substrate W of the same type. Next, the controller Ctr controls the transport arms A1 and A2 to take one substrate W from the carrier 7 and transport it into one of the liquid processing units U. The substrate W transported into the liquid processing unit U is held by suction in the holding unit 13 (see step S1 in Figure 9).

[0048] Next, the controller Ctr controls the rotation and holding unit 10 to rotate the substrate W while holding the lower surface Wb of the substrate W with the holding unit 13. In this state, the controller Ctr controls the supply unit 20 to supply etching solution L1 from the nozzle 24 to the surface of the substrate W for a predetermined time (see step S2 in Figure 9). At this time, the nozzle 24 and arm 26 may perform a scan-in or scan-out operation. The etching solution L1 supplied to the surface of the substrate W spreads over the entire surface of the substrate W due to the rotation of the substrate W and is swept outward from the periphery of the substrate W. Therefore, as long as the supply of etching solution L1 from the nozzle 24 continues, a liquid film of etching solution L1 is formed on the surface of the substrate W. As a result, the film F is etched.

[0049] Next, the controller Ctr controls the rotation and holding unit 10 to rotate the substrate W while holding the lower surface Wb of the substrate W with the holding unit 13. In this state, the controller Ctr controls the supply unit 30 to supply rinse liquid L2 from the nozzle 34 to the surface of the substrate W for a predetermined time (see step S3 in Figure 9). At this time, the nozzle 34 and arm 36 may perform a scan-in or scan-out operation. The rinse liquid L2 supplied to the surface of the substrate W spreads over the entire surface of the substrate W due to the rotation of the substrate W and is swept outward from the periphery of the substrate W. Therefore, as long as the supply of rinse liquid L2 from the nozzle 34 continues, a liquid film of rinse liquid L2 is formed on the upper surface Wa of the substrate W. As a result, the surface of the substrate W is cleaned.

[0050] On the other hand, while the etching solution L1 and rinsing solution L2 are supplied to the substrate surface in steps S2 and S3, the controller Ctr controls the optical sensors 41 to 43. As a result, the optical sensors 41 to 43 irradiate light onto the irradiation points P1 to P3 and acquire intensity change data, which is data indicating the change in reflection intensity, for each irradiation point P1 to P3 (see step S4 in Figure 9). Figure 10 is a graph showing an example of intensity change data at irradiation point P1. As shown in Figure 10, while the etching solution L1 is being supplied, the reflection intensity is greatly disturbed as the nozzle 24 and arm 26 perform scan-in or scan-out operations. This is because, as the nozzle 24 and arm 26 move, they overlap with the optical path of the optical sensor 40, or the etching solution L1 discharged from the nozzle 24 becomes wavy on the substrate surface (see Figure 12).

[0051] Therefore, the controller Ctr removes the disturbance components generated by the influence of the nozzle 24 or arm 26 from the intensity change data and generates corrected data (see step S5 in Figure 9). Corrected data is generated for each of the intensity change data acquired for each irradiation location P1 to P3. Figure 11 is a graph showing the corrected data after removing disturbance components from the data during the etching solution L1 supply period among the intensity change data exemplified in Figure 10, and shows an enlarged view of the dashed circled area in Figure 10.

[0052] Removal of disturbance components from intensity change data may be performed, for example, based on at least one of the position of the nozzle 24 or arm 26 and the supply flow rate of the etching solution L1 from the nozzle 24. More specifically, as the nozzle 24 or arm 26 moves, if their positions approach the irradiation points P1 to P3, the optical path of the light from the photosensor 40 overlaps with them, causing a significant disturbance in the reflected intensity. Therefore, when the nozzle 24 or arm 26 approaches within a predetermined range of the irradiation points P1 to P3, the intensity change data at that time may be excluded, or the irradiation of light from the photosensor 40 may be stopped. Alternatively, if the supply flow rate of the etching solution L1 from the nozzle 24 increases, the etching solution L1 is more likely to become turbulent on the surface of the substrate W. Therefore, when the supply flow rate exceeds a predetermined size, the intensity change data at that time may be excluded, or the irradiation of light from the photosensor 40 may be stopped. Furthermore, since the processing conditions for the substrate W (such as the movement path of the arm 26 and the supply flow rate of the etching solution L1) are predetermined as a so-called recipe, the timing for removing disturbance components from the intensity change data may be set based on these processing conditions.

[0053] Next, the controller Ctr estimates the film thickness of film F based on the correction data generated in step S5 (see step S6 in Figure 9). Specifically, it estimates the film thickness of film F based on the model stored in the memory unit M2 and the reflectance of the correction data. By estimating the film thickness during the etching process of film F, it becomes possible to grasp the progress of etching in real time. The process in step S6 is performed for each correction data corresponding to the irradiation locations P1 to P3. Therefore, the film thickness of film F is estimated for each of the irradiation locations P1 to P3.

[0054] Incidentally, as illustrated in Figures 5 and 6, some models may have extreme values. Therefore, there may be two film thicknesses corresponding to a certain reflectance value, but since the film thickness decreases as etching progresses, it is possible to determine which of the two film thicknesses to estimate is correct based on the progress of etching. Note that the processes in steps S4 to S6 may be performed before supplying the etching solution L1 to the substrate W, as illustrated in Figure 10, or they may be performed continuously after the supply of the rinsing solution L2 to the substrate W has finished.

[0055] After the supply of rinsing solution L2 to the substrate W is complete and the substrate W is finished, the controller Ctr compares the estimated film thickness at each of the irradiation locations P1 to P3 (see step S7 in Figure 9). Specifically, it calculates the difference between the maximum and minimum values ​​of these estimated film thicknesses. Next, it is determined whether this difference is smaller than a predetermined threshold (see step S8 in Figure 9). If this difference is smaller than the predetermined threshold, it is determined that the variation in estimated film thickness at each of the irradiation locations P1 to P3 is small, and therefore the in-plane uniformity of the film thickness of the film F after etching is within an acceptable range (see "YES" in step S8 in Figure 9). Therefore, after step S8, the processing of the substrate W is completed. Subsequently, the processing of the next substrate W may be performed using the same liquid processing unit U under the same processing conditions.

[0056] On the other hand, if the difference exceeds a predetermined threshold, it is determined that the in-plane uniformity of the film thickness of the film F after etching is outside the acceptable range because there is a large variation in the estimated film thickness at each of the irradiation locations P1 to P3 (see "NO" in step S8 of Figure 9). In this case, there may be room to improve the processing conditions of the substrate W. Therefore, the controller Ctr changes the processing conditions of the subsequent substrate W (see step S9 of Figure 9). Examples of processing conditions that are changed here include the discharge position of the etching solution L1 discharged onto the subsequent substrate W and the flow rate of the etching solution L1 discharged onto the subsequent substrate W. After step S9, the processing of the substrate W is completed, and the subsequent substrate W is processed by the liquid processing unit U under the new processing conditions.

[0057] [Effect] As shown in the above example, since the intensity of reflected light changes depending on the film thickness, the film thickness, which changes moment by moment during the etching process, can be estimated by using the intensity change data. Moreover, since correction data is generated by removing disturbance components from the intensity change data, even if disturbances (nozzle 24, arm 26) cause disturbances in the intensity change data, the film thickness can be estimated accurately by using the correction data. As a result, it is possible to accurately estimate the film thickness, which changes moment by moment during the etching process, even in a disturbed environment.

[0058] As shown in the above example, even if the etching solution L1 is supplied to the substrate surface while moving the arm 26 and nozzle 24 above the substrate W so that the etching solution L1 spreads substantially uniformly across the substrate W, disturbance components generated by the arm 26 or nozzle 24 are removed. Therefore, it becomes possible to perform the etching process with greater precision while accurately estimating the film thickness, which changes moment by moment during the etching process.

[0059] As shown in the above example, when the position of the disturbance-inducing object (nozzle 24, arm 26) approaches a predetermined range near the irradiation points P1 to P3, or when the supply flow rate of the etching solution L1 exceeds a predetermined value, the reflected light intensity data is excluded. Therefore, correction data can be generated more accurately. Consequently, even in a disturbed environment, it becomes possible to estimate the film thickness, which changes moment by moment during the etching process, with greater accuracy.

[0060] As shown in the above example, by acquiring the model in advance, the film thickness can be immediately estimated from the intensity of the reflected light received by the light sensor 40. Therefore, it is possible to accurately and immediately estimate the film thickness, which changes moment by moment during the etching process.

[0061] As shown in the above example, the film thickness at multiple different locations (irradiation points P1 to P3) in the radial direction of the substrate W can be estimated. Therefore, based on the estimated multiple film thicknesses, it becomes possible to understand the in-plane uniformity of the substrate W after etching.

[0062] As shown in the above example, the processing conditions for the subsequent substrate W are changed based on the in-plane uniformity of the substrate W, which is determined based on multiple estimated film thicknesses. As a result, the in-plane uniformity of the subsequent substrate W due to the etching process is improved. In other words, the processing conditions for the substrate W are adjusted so that the processing results of the subsequent substrate W are better. Therefore, it becomes possible to process the substrate W more appropriately.

[0063] [Differentiation] The disclosures herein should be considered in all respects to be illustrative and not restrictive. Various omissions, substitutions, and modifications may be made to the above examples without departing from the claims and the gist thereof.

[0064] (1) The etching solution L1 may be supplied to the surface of the substrate W while the substrate W is not rotating.

[0065] (2) The photosensor 40 may be configured to irradiate the same irradiation area with light La~Lc of different wavelengths. In the example in Figure 12, the photosensor 41 may be configured to irradiate the irradiation area P1 with light La~Lc of three different wavelengths. The photosensor 42 may be configured to irradiate the irradiation area P2 with light La~Lc of three different wavelengths. The photosensor 43 may be configured to irradiate the irradiation area P3 with light La~Lc of three different wavelengths. The photosensor 40 may independently receive reflected light Ra~Rc of different wavelengths of light La~Lc, for example, through a filter. The controller Ctr may estimate the film thickness at each of the irradiation areas P1~P3 based on the respective intensities of the reflected light Ra~Rc and a model.

[0066] Here, the model may represent the relationship between the film thickness of the film F and the intensities of the reflected light Ra to Rc. The method for generating the model may be the same as the method described above. An example of the model is shown in Figure 13. Figure 13(a) is an example of a model representing the relationship between the film thickness at the irradiation point P1 (50 mm) and the intensities of the reflected light Ra to Rc when using a substrate W in which the film F is formed of titanium nitride. Figure 13(b) is an example of a model representing the relationship between the film thickness at the irradiation point P1 (50 mm) and the intensities of the reflected light Ra to Rc when using a substrate W in which the film F is formed of silicon nitride (SiN). Figure 13(c) is an example of a model representing the relationship between the film thickness at the irradiation point P1 (50 mm) and the intensities of the reflected light Ra to Rc when using a substrate W in which the film F is formed of a thermal oxide film (Th-Ox). As shown in Figure 13, the relationship between the film thickness and the intensity of the reflected light will also differ depending on the wavelength of light. Therefore, by using light of multiple wavelengths and estimating the film thickness based on the intensity of the reflected light, it is possible to improve the accuracy of the film thickness estimation.

[0067] (3) The controller Ctr may obtain the film thickness of the substrate W before and after etching based on the reflection intensity and calculate the etching result (e.g., etching amount, etching rate, etc.) for one etching process. The controller Ctr may determine whether the calculated etching result is within a predetermined tolerance range. If the result of the determination is that the calculated etching result is not within the tolerance range, there is a possibility that the processing of the substrate W is inappropriate. For this reason, the controller Ctr may store the determination that the processing is inappropriate in the storage unit M2. In this case, the controller Ctr may provide an alarm from a notification unit (not shown) indicating that the etching result is not within the tolerance range (for example, the alarm may be displayed on the display, or an alarm sound or alarm guidance may be emitted from the speaker). After that, the processing of the subsequent substrate W may be interrupted, or the processing of the subsequent substrate W may be performed using a liquid processing unit U different from the liquid processing unit U that may have performed the inappropriate processing of the substrate W.

[0068] The controller Ctr may arrange the calculated etching results in chronological order and store them in the memory unit M2 as a so-called log. Based on the log information accumulated over time, the controller Ctr may predict when the etching results are expected to fall outside the acceptable range in the future. For example, if the time-series data of etching results constituting the log is gradually increasing over time, the controller Ctr may calculate an approximation line to predict when the future etching results will exceed the acceptable range. If the time-series data of etching results constituting the log is gradually decreasing over time, the controller Ctr may calculate an approximation line to predict when the future etching results will fall below the acceptable range.

[0069] (4) The techniques disclosed herein may be applied to measure the line width and pattern shape of a pattern formed on the surface of the substrate. That is, the line width and pattern shape of the pattern may be measured by irradiating the pattern with light from the optical sensor 40 and measuring the intensity of the reflected light.

[0070] [Other examples] Example 1. An example of a substrate processing apparatus comprises a holding unit configured to hold a substrate on which a film is formed on its surface, a supply unit configured to supply an etching solution to the surface of the substrate, a photosensor configured to irradiate a predetermined wavelength of light toward an irradiation point set to overlap with the surface of the substrate held by the holding unit, and to receive the reflected light, and a control unit. The control unit is configured to perform the following: a first process of controlling the supply unit to supply an etching solution to the surface of the substrate held by the holding unit; a second process of acquiring the change in the intensity of the reflected light from the irradiation point received by the photosensor while the etching solution is being supplied to the surface of the substrate; a third process of removing disturbance components caused by disturbance-inducing objects located above the substrate from the intensity change data showing the change in the intensity of the reflected light acquired in the second process, and generating correction data; and a fourth process of estimating the film thickness during the etching process based on the correction data. In this case, since the intensity of the reflected light changes according to the film thickness, the film thickness, which changes moment by moment during the etching process, can be estimated by using the intensity change data. Furthermore, since the disturbance component is removed from the intensity change data to generate corrected data, even if disturbances cause disturbances in the intensity change data, the film thickness can be accurately estimated using the corrected data. As a result, it becomes possible to accurately estimate the film thickness, which changes moment by moment during the etching process, even in a disturbed environment.

[0071] Example 2. In the apparatus of Example 1, the supply unit includes a nozzle configured to discharge etching solution and an arm configured to hold the nozzle and move the nozzle along the surface of the substrate above the substrate, and the disturbance inducer may be the arm or the nozzle. In this case, for example, even if the etching solution is supplied to the surface of the substrate while moving the arm and nozzle above the substrate so that the etching solution spreads substantially uniformly across the substrate surface, disturbance components generated by the arm or nozzle are removed. Therefore, it becomes possible to perform the etching process with greater precision and to accurately estimate the film thickness, which changes moment by moment during the etching process.

[0072] Example 3. In the apparatus of Example 2, the disturbance component may be generated by the arm or nozzle overlapping with the optical path of the optical sensor, or by the etching solution discharged from the nozzle disturbing the liquid film on the surface of the substrate.

[0073] Example 4. In any of the apparatuses in Examples 1 to 3, the third process may include generating corrected data by removing disturbance components from the intensity change data based on at least one of the location of the disturbance-inducing object and the supply flow rate of the etching solution by the supply unit. Generally, the closer the irradiation point of the light from the optical sensor is to the location of the disturbance-inducing object, the more likely it is that the optical path of the light and the disturbance-inducing object will overlap, so disturbance components tend to appear in the intensity change data. Also, the higher the supply flow rate of the etching solution, the more likely it is that the etching solution film will become wavy on the surface of the substrate, so disturbance components tend to appear in the intensity change data. Therefore, when the location of the disturbance-inducing object approaches a predetermined range near the irradiation point, or when the supply flow rate of the etching solution exceeds a predetermined value, corrected data can be generated more accurately by excluding the intensity data of reflected light. Thus, even in a disturbed environment, it becomes possible to estimate the film thickness, which changes moment by moment during the etching process, with greater accuracy.

[0074] Example 5. In any of the apparatuses in Examples 1 to 4, the fourth process may include estimating the film thickness on the substrate from the intensity included in the correction data, based on a model representing the relationship between the film thickness formed on the surface of the sample substrate and the intensity of the reflected light obtained by irradiating the surface of the sample substrate with light using a photosensor and receiving the reflected light. In this case, by acquiring the model in advance, the film thickness can be immediately estimated from the intensity of the reflected light received by the photosensor. Therefore, it becomes possible to accurately and immediately estimate the film thickness, which changes moment by moment during the etching process.

[0075] Example 6. In any of the devices in Examples 1 to 5, the optical sensor is configured to irradiate the irradiation area with light and light of a predetermined different wavelength, and to receive the reflected light from each. The second process may include obtaining the change in the intensity of the reflected light from one light and the change in the intensity of the reflected light from the other light while the etching solution is being supplied to the surface of the substrate. Incidentally, the relationship between film thickness and the intensity of reflected light will also differ if the wavelength of light is different. Therefore, by using light of multiple wavelengths and estimating the film thickness based on the intensity of the reflected light from each, it is possible to improve the accuracy of the film thickness estimation.

[0076] Example 7. Any apparatus of Examples 1 to 6 may further include another photosensor configured to irradiate light toward another irradiation location that overlaps with the surface of the substrate held in the holding unit and is set at a different position in the radial direction of the substrate from the irradiation location, and to receive the reflected light. The control unit may further perform a fifth process during the supply of etching solution to the surface of the substrate, which involves acquiring a change in the intensity of the reflected light from the irradiation location received by the other photosensor; a sixth process that removes disturbance components caused by disturbance inducers from the intensity change data showing the change in the intensity of the reflected light acquired in the fifth process, and generates other correction data; and a seventh process that estimates the film thickness during the etching process based on the other correction data. In this case, the film thickness at multiple different positions in the radial direction of the substrate can be estimated. Therefore, it becomes possible to grasp the in-plane uniformity of the substrate during the etching process based on the estimated multiple film thicknesses.

[0077] Example 8. In the apparatus of Example 7, the control unit may be configured to further perform an eighth process that changes at least one of the discharge position of the etching solution discharged onto the subsequent substrate by the supply unit and the flow rate of the etching solution discharged onto the subsequent substrate by the supply unit, based on the film thickness estimated in the fourth process and the film thickness estimated in the seventh process. In this case, the processing conditions of the subsequent substrate are changed based on the in-plane uniformity of the substrate after etching as determined in Example 7. As a result, the in-plane uniformity of the subsequent substrate after etching is improved. That is, the processing conditions of the substrate are adjusted so that the processing results of the subsequent substrate are better. Therefore, it becomes possible to process the substrate more appropriately.

[0078] Example 9. In any of the apparatuses of Examples 1 to 8, the holding unit is configured to rotate the substrate while holding it, and the first process may include controlling the supply unit and the holding unit to supply etching solution to the surface of the rotating substrate.

[0079] Example 10. An example of a film thickness estimation method includes: a first step of supplying etching solution to the surface of a substrate with a film formed on its surface, while the substrate is held in a holding unit; a second step of irradiating the substrate held in the holding unit with light of a predetermined wavelength using a photosensor while the etching solution is being supplied to the substrate surface, and acquiring the change in intensity of the reflected light from the irradiated area received by the photosensor; a third step of generating corrected data by removing disturbance components caused by disturbance-inducing objects located above the substrate from the intensity change data showing the change in intensity of the reflected light acquired in the second step; and a fourth step of estimating the film thickness during the etching process based on the corrected data. In this case, the same effects as in Example 1 can be obtained.

[0080] Example 11. In the method of Example 10, the supply unit includes a nozzle configured to discharge etching solution and an arm configured to hold the nozzle and move the nozzle along the surface of the substrate above the substrate, and the disturbance inducer may be the arm or the nozzle. In this case, the same effects as in Example 2 can be obtained.

[0081] Example 12. In the method of Example 11, the disturbance component may be generated by the arm or nozzle overlapping with the optical path of the optical sensor, or by the etching solution discharged from the nozzle disturbing the liquid film on the surface of the substrate.

[0082] Example 13. In any of the methods in Examples 10 to 12, the third step may include generating corrected data by removing the disturbance component from the intensity change data based on at least one of the location of the disturbance inducer and the supply flow rate of the etching solution by the supply unit. In this case, the same effects as in Example 4 can be obtained.

[0083] Example 14. In any of the methods in Examples 10 to 13, the fourth step may include estimating the film thickness on the substrate from the intensity included in the correction data, based on a model that represents the relationship between the film thickness formed on the surface of the sample substrate and the intensity of the reflected light obtained by irradiating the surface of the sample substrate with light using a photosensor and receiving the reflected light. In this case, the same effects as in Example 5 can be obtained.

[0084] Example 15. In any of the methods of Examples 10 to 14, the light sensor is configured to irradiate the irradiation area with light and light of a predetermined other wavelength, and to receive the reflected light of each, and the second step may include obtaining the change in the intensity of the reflected light of the light and the change in the intensity of the reflected light of the other light while the etching solution is being supplied to the surface of the substrate. In this case, the same effects as in Example 6 can be obtained.

[0085] Example 16. Any of the methods in Examples 10 to 15 may further include: a fifth step of irradiating a predetermined different wavelength of light toward another irradiation site on the substrate held in the holding unit with another photosensor while an etching solution is being supplied to the surface of the substrate, and acquiring a change in the intensity of the reflected light from the other irradiation site received by the other photosensor, wherein the other irradiation site is set to a position different from the irradiation site in the radial direction of the substrate; a sixth step of removing disturbance components caused by disturbance inducers from the intensity change data showing the change in the intensity of the reflected light acquired in the fifth step to generate different correction data; and a seventh step of estimating the film thickness during the etching process based on the different correction data. In this case, the same effects as in Example 7 can be obtained.

[0086] Example 17. The method of Example 16 may further include an eighth step in which, based on the film thickness estimated in the fourth step and the film thickness estimated in the seventh step, at least one of the discharge position of the etching solution discharged onto the subsequent substrate by the supply unit and the flow rate of the etching solution discharged onto the subsequent substrate by the supply unit is changed. In this case, the same effects as in Example 8 can be obtained.

[0087] Example 18. In any of the methods of Examples 10 to 17, the holding unit is configured to rotate the substrate while holding it, and the first step may include controlling the supply unit and the holding unit to supply etching solution to the surface of the rotating substrate. [Explanation of symbols]

[0088] 1...Substrate processing system (substrate processing device), 10...Rotating holding unit (holding unit), 13...Holding unit, 20...Supply unit, 24...Nozzle (disturbance inducer), 26...Arm (disturbance inducer), 40...Optical sensor, Ctr...Controller (control unit), F...Film, Fa...Top surface (surface), L1...Etching solution, P1~P3...Irradiation area, U...Liquid processing unit (substrate processing device), W...Substrate.

Claims

1. A holding part configured to hold a substrate on which a film is formed on the surface, A supply unit configured to supply etching solution to the surface of the substrate, A light sensor configured to irradiate light of a predetermined wavelength toward an irradiation area set to overlap with the surface of the substrate held in the holding part, and to receive the reflected light, It includes a control unit, The control unit, A first process involves controlling the supply unit to supply etching solution to the surface of the substrate held by the holding unit, During the supply of etching solution to the surface of the substrate, a second process is performed to acquire the change in the intensity of the reflected light from the irradiated area received by the light sensor, A third process involves removing disturbance components generated by disturbance-inducing objects located above the substrate from the intensity change data showing the change in the intensity of reflected light acquired in the second process, and generating corrected data. The system is configured to perform a fourth process, which estimates the film thickness during etching based on the correction data, The substrate processing apparatus comprises, the third process, generating the correction data by removing the disturbance component from the intensity change data based on at least one of the location of the disturbance inducer and the supply flow rate of the etching solution by the supply unit.

2. The aforementioned supply unit is A nozzle configured to dispense etching solution, The set includes an arm that holds the nozzle and moves the nozzle along the surface of the substrate above the substrate, The apparatus according to claim 1, wherein the disturbance inducer is the arm or the nozzle.

3. The apparatus according to claim 2, wherein the disturbance component is generated when the arm or the nozzle overlaps with the optical path of the optical sensor, or when the liquid film on the surface of the substrate is disturbed by the etching solution discharged from the nozzle.

4. The apparatus according to claim 1, wherein the fourth process includes estimating the thickness of the film on the substrate from the intensity included in the correction data, based on a model representing the relationship between the thickness of the film formed on the surface of the sample substrate and the intensity of the reflected light obtained by the photosensor irradiating the surface of the sample substrate with light and receiving the reflected light.

5. The light sensor is configured to irradiate the irradiation area with the light and light of a predetermined other wavelength, and to receive the reflected light from each. The apparatus according to any one of claims 1 to 4, wherein the second process includes obtaining a change in the intensity of the reflected light of the light and a change in the intensity of the reflected light of the light of another wavelength while supplying the etching solution to the surface of the substrate.

6. The collection further includes another light sensor configured to emit light toward another irradiation location that overlaps with the surface of the substrate held in the holding portion and is set at a position different in the radial direction of the substrate from the irradiation location, and to receive the reflected light, The control unit, A fifth process is performed during the supply of etching solution to the surface of the substrate, in which the change in the intensity of reflected light from the irradiated area, received by the other photosensor, A sixth process involves removing the disturbance component caused by the disturbance inducer from the intensity change data showing the change in the intensity of reflected light obtained in the fifth process, and generating separate corrected data. The apparatus according to claim 1, further configured to perform a seventh process of estimating the thickness of the film during etching based on the aforementioned correction data.

7. The apparatus according to claim 6, wherein the control unit is configured to further perform an eighth process, which involves changing at least one of the discharge position of the etching solution discharged onto a subsequent substrate by the supply unit and the flow rate of the etching solution discharged onto a subsequent substrate by the supply unit, based on the film thickness estimated in the fourth process and the film thickness estimated in the seventh process.

8. The holding part is configured to rotate the substrate while holding it, The apparatus according to claim 1, wherein the first process includes controlling the supply unit and the holding unit to supply an etching solution to the surface of the rotating substrate.

9. The first step involves supplying an etching solution to the surface of a substrate, while the substrate, on which a film is formed, is held in a holding unit, and the supply unit supplies the etching solution to the surface of the substrate. A second step involves supplying etching solution to the surface of the substrate, irradiating the substrate held in the holding unit with light of a predetermined wavelength using a photosensor, and obtaining the change in the intensity of the reflected light from the irradiated area received by the photosensor. A third step involves generating corrected data by removing disturbance components caused by disturbance-inducing objects located above the substrate from the intensity change data showing the change in the intensity of reflected light acquired in the second step, The process includes a fourth step of estimating the film thickness during etching based on the correction data, A method for estimating film thickness, comprising the third step of generating corrected data by removing the disturbance component from the intensity change data based on at least one of the location of the disturbance inducer and the supply flow rate of the etching solution by the supply unit.

10. The aforementioned supply unit is A nozzle configured to dispense etching solution, The set includes an arm that holds the nozzle and moves the nozzle along the surface of the substrate above the substrate, The method according to claim 9, wherein the disturbance inducer is the arm or the nozzle.

11. The method according to claim 10, wherein the disturbance component is generated by the arm or the nozzle overlapping with the optical path of the optical sensor, or by the etching solution discharged from the nozzle disturbing the liquid film on the surface of the substrate.

12. The method according to claim 9, wherein the fourth step includes estimating the thickness of the film on the substrate from the intensity included in the correction data, based on a model representing the relationship between the thickness of the film formed on the surface of the sample substrate and the intensity of the reflected light obtained by the photosensor irradiating the surface of the sample substrate with light and receiving the reflected light.

13. The light sensor is configured to irradiate the irradiation area with the light and light of a predetermined other wavelength, and to receive the reflected light from each. The method according to any one of claims 9 to 12, wherein the second step includes obtaining a change in the intensity of the reflected light of the light and a change in the intensity of the reflected light of the light of the other wavelength while the etching solution is being supplied to the surface of the substrate.

14. A fifth step, during the supply of etching solution to the surface of the substrate, in which a predetermined different wavelength of light is irradiated by another photosensor toward another irradiation location of the substrate held in the holding part, and the change in the intensity of the reflected light from the other irradiation location received by the other photosensor is obtained, wherein the other irradiation location is set at a position different from the irradiation location in the radial direction of the substrate, A sixth step involves removing the disturbance component caused by the disturbance-inducing object from the intensity change data showing the change in the intensity of reflected light acquired in the fifth step, and generating separate corrected data. The method according to claim 9, further comprising a seventh step of estimating the thickness of the film during etching based on the aforementioned correction data.

15. The method according to claim 14, further comprising an eighth step of changing at least one of the discharge position of the etching solution discharged onto a subsequent substrate by the supply unit and the flow rate of the etching solution discharged onto a subsequent substrate by the supply unit, based on the film thickness of the film estimated in the fourth step and the film thickness of the film estimated in the seventh step.

16. The holding part is configured to rotate the substrate while holding it, The method according to claim 9, wherein the first step includes controlling the supply unit and the holding unit to supply an etching solution to the surface of the rotating substrate.

Images