Substrate processing method and substrate processing device

Abstract

To reduce impurities remaining on a substrate after chemical processing.SOLUTION: A chemical solution is supplied to a substrate having a rinse liquid film formed on one major surface of the substrate. Thereby, a main flow region in which the chemical solution flows toward the outside of the substrate is formed on a viscous bottom layer composed of the rinse liquid on the one main surface of the substrate, and a chemical solution component contained in the chemical solution is quickly diffused from the main flow region to the viscous bottom layer and reaches the one main surface of the substrate to perform chemical solution processing. On the other hand, impurities diffuse from the main flow region to the viscous bottom layer with a delay. In the present invention, before the impurities diffuse from the main flow region to the viscous bottom layer and reach the one main surface, the rinse liquid is supplied to the one main surface that has been subjected to the chemical solution processing, and the chemical solution and the impurities present in the main flow region are washed away to the outside of the substrate.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a substrate processing method and a substrate processing apparatus for performing chemical processing using a chemical liquid and rinsing processing using a rinse liquid on a substrate. [Background technology]

[0002] There is known a substrate processing apparatus that supplies a chemical solution to a substrate held by a spin chuck to perform a chemical process such as etching. For example, in the apparatus described in Patent Document 1, after the chemical process, a rinse process is performed in which a rinse solution such as deionized water (DIW) is supplied to the substrate to wash away the chemical solution on the substrate, and a drying process is performed in which the rinse solution adhering to the substrate is shaken off from the substrate and dried. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-70067 Summary of the Invention [Problem to be solved by the invention]

[0004] When performing these substrate processing tasks, reducing the number of particles remaining on the substrate is one of the most important issues from the perspective of improving yield. Therefore, chemicals and rinse solutions are typically filtered to remove particles before being used in substrate processing. However, for chemicals such as hydrochloric acid (HCl) and hydrofluoric acid (HF), the number of filters available for particle removal is limited, so the particle concentration in chemicals is higher than that in rinse solutions such as DIW. Therefore, there is a need for substrate processing technology that can reduce the number of particles remaining on the substrate after chemical processing.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a substrate processing method and a substrate processing apparatus that can reduce impurities remaining on a substrate after chemical processing. [Means for solving the problem]

[0006] A first aspect of the present invention is a substrate processing method comprising: a rinse liquid film formation process for supplying a rinse liquid to one main surface of the substrate to form a rinse liquid film on the one main surface of the substrate; a first chemical liquid process for supplying a chemical liquid containing a chemical liquid component toward the one main surface of the substrate having the rinse liquid film formed by the rinse liquid film formation process, thereby forming a mainstream region on the one main surface of the substrate on a viscous bottom layer composed of the rinse liquid, in which the chemical liquid flows toward the outside of the substrate, and processing the one main surface of the substrate with the chemical liquid component that diffuses from the mainstream region into the viscous bottom layer and reaches the one main surface of the substrate; and a rinse process for supplying a rinse liquid to perform a rinse treatment on the entire one main surface of the substrate before impurities contained in the chemical liquid and having a diffusion coefficient smaller than that of the chemical liquid component diffuse from the mainstream region into the viscous bottom layer and reach the one main surface of the substrate.

[0007] A second aspect of the present invention is a substrate processing apparatus comprising: a substrate holding unit that holds a substrate with one main surface of the substrate facing upward; a rinse liquid supply unit that supplies a rinse liquid to the one main surface of the substrate held by the substrate holding unit; a chemical liquid supply unit that supplies a chemical liquid to the one main surface of the substrate held by the substrate holding unit; and a control unit that controls the rinse liquid supply unit and the chemical liquid supply unit so as to perform the substrate processing method.

[0008] In the invention configured as described above, a chemical solution is supplied to a substrate having a rinse liquid film formed on one main surface of the substrate. At this time, as described below, a main region of the chemical solution is formed on a viscous bottom layer composed of the rinse liquid on one main surface of the substrate. In other words, in the main region, the chemical solution flows toward the outside of the substrate, pushing the rinse liquid on the viscous bottom layer away from the substrate. Meanwhile, in the viscous bottom layer, the flow velocity within the layer is extremely slow, so the rinse liquid is not immediately replaced by the chemical solution and remains. Therefore, immediately after the chemical solution is dispensed, a main region composed of the chemical solution and a viscous bottom layer composed of the rinse liquid are temporarily formed on one main surface of the substrate. The chemical solution may contain not only chemical solution components but also impurities such as particles. The diffusion coefficients of the chemical solution components and the impurities are compared, and the impurities' diffusion coefficient is smaller than that of the chemical solution components. Therefore, the chemical solution components in the main region of the chemical solution diffuse quickly from the main region to the viscous bottom layer, reaching the one main surface of the substrate and performing chemical processing. Meanwhile, impurities diffuse from the main region to the viscous bottom layer with a delay. Therefore, in the present invention, before the impurities diffuse from the mainstream region into the viscous bottom layer and reach one main surface of the substrate, a rinse liquid is supplied to the entire one main surface that has been subjected to the above-mentioned chemical treatment, and the chemical liquid containing the impurities is washed away. [Effects of the Invention]

[0009] As described above, according to the present invention, it is possible to reduce impurities remaining on a substrate after chemical processing. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a plan view showing a schematic configuration of a substrate processing system equipped with an embodiment of a substrate processing apparatus according to the present invention. [Figure 2] 1 is a diagram showing a configuration of a main part of a substrate processing apparatus according to the present invention; [Figure 3] 3 is a flowchart showing a substrate processing method executed by the substrate processing apparatus shown in FIG. [Figure 4] 1A to 1C are diagrams schematically illustrating main operations in a substrate processing method. DETAILED DESCRIPTION OF THE INVENTION

[0011] 1 is a plan view showing the schematic configuration of a substrate processing system equipped with one embodiment of a substrate processing apparatus according to the present invention. This is not a view showing the external appearance of the substrate processing system 100, but rather a schematic view showing the internal structure of the substrate processing system 100 by excluding the outer wall panels and other components. The substrate processing system 100 is a single-wafer processing apparatus that is installed, for example, in a clean room and processes substrates S one by one.

[0012] The substrate processing system 100 includes a plurality of processing units (substrate processing apparatuses) 1, each of which mainly processes a substrate S. Although four processing units 1 are shown arranged horizontally in FIG. 1, the processing units 1 can also be stacked vertically in multiple stages. For example, when the processing units 1 are stacked in six stages, the substrate processing system 100 includes a total of 24 processing units 1.

[0013] As will be described later, each of the plurality of processing units 1 provided in the substrate processing system 100 receives a substrate S, performs chemical processing and rinsing processing on the upper surface of the substrate S, and then performs drying processing to dry the substrate S. In other words, the processing unit 1 corresponds to an example of a substrate processing apparatus 10 capable of performing an embodiment of a substrate processing method according to the present invention.

[0014] Here, the "substrate" in this embodiment can be any of various substrates, such as a semiconductor wafer, a glass substrate for a photomask, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a substrate for an FED (Field Emission Display), a substrate for an optical disk, a substrate for a magnetic disk, a substrate for a magneto-optical disk, etc. The following description will be given with reference to the drawings, taking as an example a substrate processing apparatus 10 used primarily for processing semiconductor wafers, but the apparatus can also be applied to processing the various substrates exemplified above.

[0015] As shown in FIG. 1, the substrate processing system 100 has a substrate processing area 110 where substrates S are processed. An indexer unit 120 is provided adjacent to the substrate processing area 110. The indexer unit 120 has a container holder 121 that can hold a plurality of containers C for accommodating the substrates S (such as 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 has an indexer robot 122 that accesses the containers C held in the container holder 121 to remove unprocessed substrates S from the container C or store processed substrates S in the container C. Each container C accommodates a plurality of substrates S in a substantially horizontal position.

[0016] 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.

[0017] 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 transfer robot 111 is disposed approximately in the center of the substrate processing area 110 in a plan view. Furthermore, a plurality of processing units 1 (substrate processing apparatuses 10) are disposed so as to surround the substrate transfer robot 111. Specifically, the plurality of processing units 1 are disposed facing the space in which the substrate transfer robot 111 is disposed. The substrate transfer robot 111 randomly accesses the mounting tables 112 for these processing units 1 and transfers the substrate S between them. In this embodiment, these processing units 1 (substrate processing apparatuses 10) have the same function. Therefore, parallel processing of a plurality of substrates S is possible. Note that the mounting tables 112 are not necessarily required if the substrate transfer robot 111 can directly transfer the substrate S from the indexer robot 122 to the substrate transfer robot 111.

[0018] Fig. 2 is a diagram showing the configuration of the main parts of a substrate processing apparatus according to the present invention. In Fig. 2, the dimensions and number of each part are exaggerated or simplified for ease of understanding. As shown in Fig. 2, the substrate processing apparatus 10 includes a chamber 11, a spin chuck 12, a spin motor 13, a chemical nozzle 14, a nozzle moving unit 15, multiple guards 16, and a rinse liquid nozzle 17.

[0019] Chamber 11 has a generally box-like shape and houses spin chuck 12, spin motor 13, chemical nozzle 14, nozzle moving unit 15, multiple guards 16, and rinse nozzle 17. Chemical processing, rinsing processing, and drying processing are performed inside chamber 11.

[0020] The spin chuck 12 has a function of holding the substrate S and corresponds to an example of a "substrate holding portion" of the present invention. More specifically, the spin chuck 12 has a spin base 12a and multiple chuck members 12b. The spin base 12a is substantially disk-shaped and is disposed in a horizontal position. The multiple chuck members 12b are disposed on the upper surface of the spin base 12a. The multiple chuck members 12b hold the substrate S in a horizontal position. The spin chuck 12 may be, for example, a vacuum chuck or a Bernoulli chuck that utilizes the Bernoulli effect, and is not particularly limited.

[0021] The spin motor 13 is connected to the spin chuck 12, and rotates the spin chuck 12 holding the substrate S about the rotation axis AX in response to a rotation command from a control unit 18 that controls the entire apparatus, causing the substrate S to also rotate about the rotation axis AX.

[0022] The chemical nozzle 14 is connected to a chemical supply unit (not shown) via a pipe P14. A valve V14 is inserted in this pipe P14. When an open command is given to this valve V14 from the control unit 18, the valve V14 opens and the chemical is supplied to the chemical nozzle 14. As a result, the chemical is supplied from the chemical nozzle 14 toward the upper surface of the substrate S held by the spin chuck 12. On the other hand, when the valve V14 is closed in response to a close command from the control unit 18, the supply of the chemical is stopped. In this way, the chemical nozzle 14 corresponds to an example of the "chemical supply unit" of the present invention.

[0023] Examples of chemical solutions include dilute hydrofluoric acid (DHF), hydrofluoric acid (HF), hydrofluoric nitric acid (a mixture of hydrofluoric acid and nitric acid (HNO3)), buffered hydrofluoric acid (BHF), ammonium fluoride, HFEG (a mixture of hydrofluoric acid and ethylene glycol), phosphoric acid (H3PO4), sulfuric acid, acetic acid, nitric acid, hydrochloric acid, ammonia water, hydrogen peroxide water, organic acids (e.g., citric acid, oxalic acid), organic alkalis (e.g., TMAH: tetramethylammonium hydroxide), sulfuric acid hydrogen peroxide water mixture (SPM), ammonia hydrogen peroxide water mixture (SC1), hydrochloric acid hydrogen peroxide water mixture (SC2), surfactants, or corrosion inhibitors.

[0024] Nozzle moving unit 15 is connected to liquid solution nozzle 14. Nozzle moving unit 15 has arm 15a, rotating shaft 15b, and nozzle moving mechanism 15c. Arm 15a extends in a substantially horizontal direction. Liquid solution nozzle 14 is attached to the tip of arm 15a, while the rear end of arm 15a is connected to rotating shaft 15b. Rotating shaft 15b extends in a substantially vertical direction and is rotatable about a rotation axis that also extends in a substantially vertical direction. Nozzle moving mechanism 15c is connected to rotating shaft 15b. While the detailed configuration of nozzle moving mechanism 15c is not shown, nozzle moving mechanism 15c has an arm swing motor (not shown) that rotates rotating shaft 15b about the rotation axis, and an arm lifting unit (not shown) that lifts and lowers arm 15a by lifting and lowering rotating shaft 15b in a substantially vertical direction. Therefore, chemical nozzle 14 moves and is positioned between the processing position and the retracted position by operating the arm swing motor and the arm lifting unit of nozzle movement mechanism 15c based on a movement command from control unit 18. Note that the processing position means a position above substrate S, and the retracted position means a position radially outward of substrate S.

[0025] The rinse liquid nozzle 17 is fixedly disposed with its outlet (not shown) facing the center of the upper surface of the substrate S held by the spin chuck 12. The rinse liquid nozzle 17 is connected to a DIW supply source (not shown) via a pipe P17. A valve V17 is inserted in the pipe P17. When an open command is given to the valve V17 from the control unit 18, the valve V17 opens and DIW is supplied to the rinse liquid nozzle 14 as the rinse liquid. As a result, the rinse liquid is supplied from the rinse liquid nozzle 17 toward the upper surface of the substrate S held by the spin chuck 12. On the other hand, when the valve V17 is closed in response to a close command from the control unit 18, the supply of the rinse liquid is stopped. In this way, the rinse liquid nozzle 17 corresponds to an example of a "rinse liquid supply unit" of the present invention.

[0026] In addition to the above-mentioned DIW, the rinse liquid may include carbonated water, electrolytic ionized water, hydrogen water, ozone water, or diluted hydrochloric acid water (for example, about 10 ppm to 100 ppm).The particle concentration in the rinse liquid is lower than that in the chemical liquid, and liquids equivalent to so-called cleaning liquids are used as rinse liquids.

[0027] The control unit 18 has an arithmetic unit such as a CPU, a storage unit such as a fixed memory device or a hard disk drive, and an input / output unit. The storage unit stores programs executed by the arithmetic unit. The control unit 18 controls each part of the substrate processing apparatus 10 in accordance with the programs, thereby performing the substrate processing described below.

[0028] Fig. 3 is a flowchart showing a substrate processing method executed by the substrate processing apparatus shown in Fig. 2. Fig. 4 is a diagram schematically showing main operations in the substrate processing method. In Fig. 4, the upper drawing shows the supply state of processing liquids (chemical liquid, rinse liquid) on the upper surface of the substrate, the middle and lower drawings show cross-sectional structures, and the dashed lines indicate the order of operations. In Fig. 4(b), the middle drawing shows the first half of the first chemical processing, as described below, while the lower drawing shows the first half of the second and subsequent chemical processing.

[0029] An unprocessed substrate S is carried into the substrate processing apparatus 10 (processing unit 1) from the container C via the mounting table 112 by the indexer robot 122 and the substrate transport robot 111 (step S1). Here, the substrate S is carried in a horizontal position with one main surface (reference symbol Sa in FIG. 4) of the substrate S to be subjected to chemical processing facing upward, and is held by the spin chuck 12.

[0030] After the substrate loading is completed and the substrate transfer robot 111 retreats from the substrate processing apparatus 10, the spin chuck 12 holding the substrate S is rotated at a first rotation speed (step S2). This first rotation speed can be set, for example, within a range of 50 rpm to 2500 rpm, and is set to 1000 rpm in this embodiment. Furthermore, supply of a rinse liquid to the upper surface Sa of the substrate S rotating at the first rotation speed is started (step S3). Specifically, DIW is ejected as the rinse liquid from the rinse liquid nozzle 17 toward the center of the upper surface of the substrate S. The rinse liquid supplied to the substrate S spreads radially from the center of the upper surface. As a result, as shown in FIG. 4(a), a rinse liquid film L1 having a thickness corresponding to the first rotation speed is formed on the upper surface Sa of the substrate S (rinse liquid film forming step). Here, when the structure of the rinse liquid film L1 is examined in detail based on boundary layer theory, the rinse liquid film L1 has a viscous bottom layer L1a and a main region L1b. That is, as shown in the lower drawing of Figure 4(a), the rinse liquid ejected onto the upper surface Sa of the rotating substrate S is divided into two layers: a viscous bottom layer L1a with almost no flow in the vertical direction, and a main layer region L1b that flows in the radial direction of the substrate S.

[0031] In step S4, a chemical processing count value n, which indicates the number of loops of the chemical processing described below, is set to an initial value of "1." Then, the process enters a chemical processing loop. In this chemical processing loop, the chemical processing of the substrate S is repeated nmax times (e.g., six times) with the viscous bottom layer L2 and the main region L3 formed on the upper surface Sa of the substrate S by laminating them in this order (steps S51 to S59). When the chemical processing starts, the chemical components in the chemical are diffused and transferred to the viscous bottom layer L1a composed of the rinse liquid, as described below, and the viscous bottom layer L1a contains the chemical components. Therefore, to distinguish between the viscous bottom layer before the start of the chemical processing (= DIW only) and the viscous bottom layer after the start of the chemical processing (= DIW + chemical components), the former is referred to as the "viscous bottom layer L1a" and the latter as the "viscous bottom layer L2."

[0032] In step S51, the supply of the rinse liquid to the upper surface Sa of the substrate S rotating at the first rotation speed is stopped. Thereafter, the rotation speed of the substrate S is changed from the first rotation speed to a second rotation speed (step S52). In this embodiment, the second rotation speed can be set, for example, within a range of 50 rpm to 2000 rpm, and in this embodiment, it is set to 500 rpm, which is lower than the first rotation speed.

[0033] Next, supply of a chemical solution to the upper surface Sa of the substrate S rotating at the second rotation speed is initiated (step S53). That is, after the chemical solution nozzle 14 moves to a processing position above the center of the upper surface of the substrate S rotating at the second rotation speed, a chemical solution such as hydrochloric acid (HCl) is discharged from the chemical solution nozzle 14. The chemical solution supplied to the substrate S spreads radially from the center of the upper surface. At this time, the above-mentioned viscous bottom layer L2 and mainstream region L3 are formed on the upper surface Sa of the substrate S, as shown in FIGS. 4(b) and 4(c). Here, as in the rinse liquid film formation process, the liquid discharged onto the upper surface Sa of the rotating substrate S is consistent with the boundary layer theory, which states that the liquid is separated into two layers: the viscous bottom layer L2, which has almost no flow in the vertical direction, and the mainstream region L3, which flows in the radial direction of the substrate S. More specifically, in the first chemical processing, in the "chemical processing (first half)" (FIG. 4(b)) immediately after the start of chemical supply, the mainstream region L1b of the rinse liquid film L1 is swept off the substrate by the chemical liquid, and the chemical liquid is replaced by the chemical liquid. As a result, a mainstream region L3 composed of the chemical liquid is formed. However, the viscous bottom layer L1a on the upper surface Sa of the substrate S remains as it is, and as the replacement progresses, the chemical liquid components in the chemical liquid are diffused and transferred from the mainstream region L3. As a result, the viscous bottom layer L1a becomes a viscous bottom layer L2 in which the chemical liquid components are dispersed in the rinse liquid (DIW). Furthermore, in the second and subsequent chemical processing, the chemical processing is performed while the viscous bottom layer L2 remains, as shown in the lower drawing of FIG. 4(b).

[0034] Although the thickness of this viscous bottom layer L2 depends on the discharge flow rate of the chemical from the chemical nozzle 14 and the rotation speed of the substrate S, it is on the order of several μm, and the rinse liquid continues to remain. This is also the case in the "chemical processing (latter half)" after time has passed. Meanwhile, as shown in FIG. 4(c), the mainstream region L3 is completely replaced by the chemical liquid. Furthermore, during this replacement with the chemical liquid, chemical components in the chemical liquid reach the upper surface Sa of the substrate S from the mainstream region L3 via the viscous bottom layer L2. As a result, a chemical processing such as an etching process is performed on the upper surface Sa of the substrate S.

[0035] Here, some of the particles PT contained in the chemical solution also diffuse from the main region L3 toward the viscous bottom layer L2, and then try to diffuse to the upper surface Sa of the substrate S. However, the diffusion coefficient of the particles PT is smaller than the diffusion coefficient of the chemical solution components. For example, the diffusion coefficient of a particle PT with a radius of 10 nm is 2.45 × 10 -7 cm 2 / sec, whereas that of the chemical component (HCl) is 3.7 x 10 -5 cm 2 / sec. Here, assuming that the thickness of the viscous bottom layer L2 is 10 μm, the time t(PT) required for the particle PT to reach the upper surface Sa of the substrate S through the viscous bottom layer L2 is t(PT) ≒ (thickness of viscous sublayer L2) 2 / (diffusion coefficient of particle PT) = 3.25 sec On the other hand, the time t(CC) required for the chemical components to reach the upper surface Sa of the substrate S through the viscous bottom layer L2 is t(CC) ≒ (thickness of viscous sublayer L2) 2 / (diffusion coefficient of drug solution component) = 0.032 sec Therefore, immediately after the start of chemical supply, the chemical components reach the upper surface Sa of the substrate S through the viscous bottom layer L2 in a short time, and in fact, chemical processing begins almost simultaneously with the start of chemical supply. On the other hand, the particles PT arrive at the upper surface Sa of the substrate S later than the chemical components. The technical matters regarding particle adhesion to the upper surface of the substrate, which are considered in this way by combining the boundary layer theory and the advection-diffusion model, are described in the following paper, N. Handa and three others, "Experimental and Modeling Investigation of Re-Adhesion Mechanism of Detached Nanoparticles to Wafer Surface in Spin Rinse Process", [online], 2 July 2020, The Electrochemical Society, [Retrieved May 13, 2024], Internet<URL:https: / / iopscience.iop.org / article / 10.1149 / 2162-8777 / ab9fe9 / meta> It is also stated in.

[0036] Based on this technical matter, the inventors of the present application have considered that chemical solution processing can be performed without causing particles PT to adhere to the upper surface Sa of the substrate S by stopping the chemical solution processing before the particles PT reach the upper surface Sa of the substrate S through the viscous bottom layer L2. Then, as shown in FIG. 3, it is determined whether a predetermined time (e.g., the time obtained by subtracting a few tenths of a second from the time t(PT)) has elapsed since the start of chemical solution supply (step S54). Then, while the determination in step S54 is "NO," the chemical solution supply continues. Meanwhile, when the predetermined time has elapsed since the start of chemical solution supply, that is, just before the time t(PT) has elapsed, the chemical solution supply is stopped (step S55).

[0037] Furthermore, in order to stop the chemical liquid processing, a rinse liquid is supplied to the upper surface Sa of the substrate S. More specifically, in step S56, it is determined whether the chemical liquid processing count value n has reached the maximum number of repetitions, i.e., nmax. Then, while the chemical liquid processing count value n has not reached nmax, steps S57 to S59 are executed, and then the process returns to step S51. Here, the case where the chemical liquid processing count value n is "1" is described, and the cases where the chemical liquid processing count value n is "2" to "nmax-1" are described later.

[0038] If the chemical liquid processing count value n is "1", that is, if the above chemical liquid processing corresponds to the "first chemical liquid process" of the present invention that is executed following the rinse liquid film forming process (step S3), the chemical liquid processing count value n is incremented by "1" in step S57, and then a rinse liquid film regeneration process (steps S58, S59) is executed. This rinse liquid film regeneration process (steps S58, S59) corresponds to an example of the "rinse liquid film regeneration process" of the present invention.

[0039] In this rinse liquid film regeneration process, the rotation speed of the substrate S is changed from the second rotation speed to the first rotation speed (step S58). In this embodiment, the rotation speed of the substrate S is increased from 500 rpm to 1000 rpm. Furthermore, supply of a rinse liquid to the upper surface Sa of the substrate S rotating at the first rotation speed is started (step S59). This flushes the chemical liquid on the upper surface Sa of the substrate S away from the substrate S, eliminating diffusion of chemical liquid components and particles PT from the mainstream region L3, and regenerating a rinse liquid film L1 on the upper surface Sa of the substrate S, as shown in FIG. 4(d). Then, the process returns to step S51, and a second chemical liquid process is performed. That is, the rotation speed of the substrate S is decelerated from the first rotation speed to the second rotation speed (step S52), and supply of the chemical liquid to the upper surface of the substrate S is started (step S53). This allows the chemical liquid process, which corresponds to an example of the "second chemical liquid process" of the present invention, to continue while the determination in step S54 is "NO." On the other hand, immediately before the time t(PT) elapses from the start of the chemical supply, the chemical supply is stopped (step S55). Such second chemical process is repeated while the chemical process count value n does not match "nmax" (determined as "NO" in step S56). In other words, the rinse liquid film regeneration process and the second chemical process are repeated.

[0040] On the other hand, when the chemical liquid processing count value n matches "nmax" ("YES" is determined in step S56), that is, when one first chemical liquid processing and five second chemical liquid processings, a total of six chemical liquid processings, are completed, the chemical liquid processing loop is exited and step S6 is proceeded to.

[0041] At the time of exiting the chemical liquid processing loop in this manner, as shown in Fig. 4(c), a viscous bottom layer L2 mainly composed of the rinse liquid and a main region L3 mainly composed of the chemical liquid are stacked in this order on the upper surface Sa of the substrate S. Therefore, in step S6, the rotation speed of the substrate S is changed to a rotation speed suitable for the rinsing process, and the rinse liquid is supplied to the upper surface Sa of the rotating substrate S. In this way, the rinsing process is performed on the upper surface Sa of the substrate S (rinsing step). Subsequently, the substrate S is rotated at high speed to dry the substrate S (step S7).

[0042] When the series of substrate processing steps for the substrate S is completed in this manner, the substrate transport robot 111 enters the substrate processing apparatus 10, receives the processed substrate S from the spin chuck 12, and removes it (step S8). The substrate S is then stored in the container C via the mounting table 112 by the substrate transport robot 111 and the indexer robot 122.

[0043] As described above, the first embodiment utilizes the advection-diffusion characteristic that the diffusion coefficient of particles PT is smaller than that of chemical components, and particles PT arrive at the upper surface Sa of the substrate S later than the chemical components. More specifically, the first through (nmax-1) chemical processes are performed by a rinse liquid film regeneration process, and the final (nmax) chemical process is performed by a rinse process. As a result, before particles PT diffuse from the mainstream region L3 into the viscous bottom layer L2 and reach the upper surface Sa of the substrate S, a rinse liquid is supplied to the upper surface Sa that has been subjected to the chemical process, washing away the chemical liquid that constitutes the mainstream region L3. This prevents particles PT from adhering to the upper surface Sa of the substrate S. As a result, it is possible to reduce impurities such as particles PT remaining on the upper surface Sa of the substrate S after chemical process.

[0044] In the above embodiment, the rotation speed of the substrate S during the chemical liquid processing is slower than that during the rinse liquid film formation processing or the rinse liquid film regeneration processing. Therefore, the viscous bottom layer L2 during the chemical liquid processing becomes thicker, and it is possible to prevent the particles PT from reaching the upper surface Sa of the substrate S. Moreover, it is possible to thin the mainstream region L3 during the rinse liquid film regeneration processing or the rinse processing, and to reduce the number of remaining particles PT.

[0045] The present invention is not limited to the above-described embodiment, and various modifications other than those described above are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, the time required for one chemical liquid processing is shortened to the predetermined time set in step S54, so that the chemical liquid processing is performed multiple times. Here, if the desired chemical liquid processing result is obtained in the first chemical liquid processing (first chemical liquid processing), the subsequent rinse liquid film regeneration processing and second chemical liquid processing may be omitted. In other words, the rinse processing (step S6) may be performed following the first chemical liquid processing (first chemical liquid processing). Furthermore, the number of repetitions of the chemical liquid processing and the rinse liquid film regeneration processing are not limited to six and five, respectively, and may be any number.

[0046] In the above embodiment, the chemical liquid processing is always performed at the second rotation speed, but the rotation speed may be changed depending on the chemical liquid processing count value n. The same applies to the rinse liquid film regeneration processing. That is, the rotation speed of the substrate S in the rinse liquid film regeneration processing may be changed depending on the chemical liquid processing count value n.

[0047] Furthermore, the types of rinse liquids and chemicals used in the processing of the above-described embodiments are only examples, and various other types can be used instead as long as they are consistent with the technical concept of the present invention described above. [Industrial Applicability]

[0048] The present invention can be applied to general substrate processing techniques that perform chemical processing using a chemical liquid and rinsing processing using a rinse liquid on a substrate. [Explanation of symbols]

[0049] 10...Substrate processing device 12...Spin chuck (substrate holder) 14...Chemical solution nozzle (chemical solution supply part) 17...Rinse liquid nozzle (rinse liquid supply part) L1...rinse liquid film L1a, L2…viscous bottom layer L3…mainstream area PT...particles (impurities) S...Substrate Sa: Top surface (one of the main surfaces of the substrate)

Claims

1. a rinse liquid film forming step of supplying a rinse liquid to one main surface of the substrate to form a rinse liquid film on the one main surface of the substrate; a first chemical process for supplying a chemical solution containing a chemical solution component toward one main surface of the substrate having the rinse liquid film formed in the rinse liquid film forming process, thereby forming a main region on the one main surface of the substrate where the chemical solution flows toward the outside of the substrate on a viscous bottom layer composed of the rinse liquid, and processing the one main surface of the substrate with the chemical solution component that diffuses from the main region into the viscous bottom layer and reaches the one main surface of the substrate; a rinsing step of supplying the rinse liquid to rinse the entire one main surface of the substrate before impurities contained in the chemical solution and having a diffusion coefficient smaller than that of the chemical solution components diffuse from the mainstream region into the viscous bottom layer and reach the one main surface of the substrate; A substrate processing method comprising:

2. The substrate processing method according to claim 1, In the rinse liquid film forming step, the rinse liquid is supplied to one main surface of the substrate, thereby forming the viscous bottom layer.

3. 2. The substrate processing method according to claim 1, The substrate processing method includes repeating the rinse liquid film forming step and the first chemical liquid step alternately multiple times.

4. 4. The substrate processing method according to claim 1, further comprising: the rinse liquid film forming step is a step of supplying the rinse liquid while rotating the substrate at a speed in the range of 50 rpm to 2500 rpm; The substrate processing method, wherein the first chemical solution step is a step of supplying the rinse solution while rotating the substrate at a speed in the range of 50 rpm to 2000 rpm.

5. 2. The substrate processing method according to claim 1, a rinse liquid film regeneration step of supplying the rinse liquid to the one main surface of the substrate before the impurities diffuse from the mainstream region into the viscous bottom layer and reach the one main surface of the substrate, thereby rinsing at least the mainstream region and regenerating a rinse liquid film on the one main surface of the substrate; a second chemical process for supplying the chemical solution toward the one main surface of the substrate on which the rinse liquid film has been formed in the rinse liquid film regeneration process, thereby forming a laminate of the viscous bottom layer and the main region, and treating the one main surface with the chemical solution components that diffuse from the main region into the viscous bottom layer and reach the one main surface of the substrate, a rinse liquid film regeneration step and a second chemical liquid step performed between the first chemical liquid step and the rinsing step;

6. 6. The substrate processing method according to claim 5, The substrate processing method includes repeating the rinse liquid film regeneration step and the second chemical liquid step multiple times.

7. 7. The substrate processing method according to claim 5, further comprising: the rinse liquid film forming step and the rinse liquid film regenerating step are steps of supplying the rinse liquid while rotating the substrate at a speed in the range of 50 rpm to 2500 rpm; The substrate processing method, wherein the first chemical solution step and the second chemical solution step are steps of supplying the rinse liquid while rotating the substrate at a speed in the range of 50 rpm to 2000 rpm.

8. a substrate holder that holds the substrate with one main surface of the substrate facing upward; a rinse liquid supply unit that supplies a rinse liquid to one main surface of the substrate held by the substrate holder; a chemical solution supply unit that supplies a chemical solution to one main surface of the substrate held by the substrate holder; a control unit that controls the rinse liquid supply unit and the chemical liquid supply unit so that the substrate processing method according to claim 1 is performed; A substrate processing apparatus comprising:

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