Substrate processing method, substrate processing apparatus, and recording medium

Abstract

The processing time of the substrate is shortened. A substrate processing method according to one embodiment includes a first process of discharging a processing solution containing hydrofluoric acid onto the surface of a substrate, a second process of discharging a rinse solution onto the surface of the substrate after the first process, and a third process of discharging a mixed fluid of hydrogen peroxide and pure water vapor or mist onto the surface of the substrate after the second process.

Description

Technology Field

[0001] The present disclosure relates to a substrate processing method, a substrate processing apparatus, and a memory medium. Background Technology

[0002] In the manufacturing process of semiconductor devices, a technique is known for removing substances such as resist films from a substrate by supplying SPM (sulfuric acid and hydrogen peroxide) to a substrate such as a semiconductor wafer. Patent document 1 describes that, in order to improve processing efficiency, SPM is mixed with pure steam and then supplied to the substrate. Prior art literature

[0003] Japanese Patent Publication No. 2023-063227 The problem to be solved

[0004] The present disclosure provides a substrate processing technology capable of reducing the processing time of a substrate. means of solving the problem

[0005] According to one aspect of the present disclosure, a substrate treatment method is provided, comprising: a first step of discharging a treatment solution containing hydrofluoric acid onto the surface of a substrate; a second step of discharging a rinse solution onto the surface of the substrate after the first step; and a third step of discharging a mixed fluid of hydrogen peroxide and pure water vapor or mist onto the surface of the substrate after the second step. Effects of the invention

[0006] According to one aspect of the present disclosure described above, the processing time of the substrate can be shortened. Brief explanation of the drawing

[0007] FIG. 1a is a schematic plan view showing the overall configuration of a substrate processing system, which is an embodiment of a substrate processing device. FIG. 1b is a schematic plan view showing an example configuration of a processing unit mounted on the substrate processing system of FIG. 1a. Figure 2 is a schematic side view of the substrate processing apparatus of Figure 1a. FIG. 3 is a diagram showing the structure of a nozzle for SPM discharge, and is a cross-sectional view obtained by cutting the nozzle with a plane perpendicular to its length direction. Figure 4 is a cross-sectional view of the nozzle along line IV-IV in Figure 3. Figure 5 is a cross-sectional view of the nozzle along the VV line in Figure 3. Figure 6 is a schematic plan view of the nozzle shown in Figures 3 to 5, viewed from below. Figure 7 is a figure showing an example of a piping system that supplies SPM and steam to a nozzle for SPM discharge. FIG. 8 is a schematic side view showing the flow of a series of processes performed on one wafer in one embodiment. FIG. 9 is a schematic side view showing the flow of a series of processes performed on one wafer in one embodiment. FIG. 10 is a schematic side view showing the flow of a series of processes performed on one wafer in one embodiment. Figure 11 is a graph showing the experimental results confirming the effect of mixing vapor with hydrogen peroxide. Specific details for implementing the invention

[0008] Hereinafter, a substrate processing apparatus (substrate processing system) according to the present disclosure and a substrate processing method executed using the same (hereinafter referred to as "embodiments") will be described in detail with reference to the drawings. Furthermore, the present disclosure is not limited by these embodiments. Additionally, each embodiment may be appropriately combined within a scope that does not contradict the processing content. Furthermore, in each of the following embodiments, the same reference numerals are assigned to identical parts, and redundant descriptions are omitted.

[0009] In addition, in the embodiments described below, expressions such as 'constant,' 'orthogonal,' 'perpendicular,' or 'parallel' may be used; however, these expressions are not strictly required to be 'constant,' 'orthogonal,' 'perpendicular,' or 'parallel.' That is, each of the above expressions allows for errors, such as manufacturing precision or installation precision.

[0010] In addition, in each drawing referenced below, for the sake of ease of understanding, mutually orthogonal X-axis, Y-axis, and Z-axis directions are defined, and an orthogonal coordinate system is shown with the Z-axis direction as the vertical upward direction. Also, the direction of rotation with the vertical axis as the center of rotation is sometimes referred to as the θ direction.

[0011] <Overall Configuration of the Substrate Processing System>

[0012] First, the overall schematic configuration of a substrate processing system (1) according to one embodiment of a substrate processing device will be explained with reference to FIG. 1a. FIG. 1a is a diagram showing the schematic configuration of a substrate processing system (1) according to a first embodiment. Hereinafter, in order to clarify the positional relationship, the X-axis, Y-axis, and Z-axis that are orthogonal to each other are defined, and the Z-axis forward direction is defined as the vertical upward direction.

[0013] As shown in FIG. 1a, a substrate processing system (1) (an example of a substrate processing device) is equipped with an incoming / outgoing station (2) and a processing station (3).

[0014] The incoming / outgoing station (2) is equipped with a carrier placement section (11) and a return section (12). A plurality of carriers (C) (e.g., FOUP) are placed in the carrier placement section (11). Each carrier (C) accommodates a plurality of substrates (in this embodiment, semiconductor wafers (W) (hereinafter, for convenience, simply referred to as 'wafers (W)')) in a horizontal position at equal intervals in the vertical direction.

[0015] Inside the return section (12), a substrate return device (13) and a delivery section (14) are provided. The substrate return device (13) is composed of a multi-axis return robot or a multi-joint return robot. The substrate return device (13) holds the wafer by means of a fork-shaped wafer holder acting as an end effector, and performs the return of the wafer (W) between the carrier (C) and the delivery section (14).

[0016] The processing station (3) is equipped with a return section (15) and a plurality of processing units (16).

[0017] A substrate transport device (17) is provided inside the transport unit (15). The substrate transport device (17) is composed of a multi-axis transport robot or a multi-joint transport robot. The substrate transport device (17) holds the wafer by means of a fork-shaped wafer holder acting as an end effector, and transports the wafer (W) between the processing unit (16) and the transfer unit (14).

[0018] The processing unit (16) performs liquid treatment by supplying a processing fluid (such as SPM in the example described below) to the wafer (W) brought in by the substrate transport device (17).

[0019] A wafer (W) contained within a carrier (C) is removed by a substrate transport device (13) of a transport unit (12) and brought into a delivery unit (14). This wafer (W) is removed by a substrate transport device (17) of a transport unit (15) and brought into a processing unit (16). The wafer, after processing in the processing unit (16), is returned to the original carrier (C) via the opposite route.

[0020] The substrate processing system (1) is equipped with a control device (4) (shown only in FIG. 1a). The control device (4) can control the operation of all operable components included in the substrate processing system (1). The control device (4) is, for example, a computer and is equipped with a control operation unit (18) and a memory unit (19). A program that controls various processes executed in the substrate processing system (1) (including a processing recipe that determines the sequence of processing) is stored in the memory unit (19). The control operation unit (18) controls the operation of the substrate processing system (1) by reading and executing the program stored in the memory unit (19). The control operation unit (18) may be a CPU (Central Processing Unit) or one or more circuits.

[0021] In addition, the above-mentioned program may be recorded on a computer-readable storage medium and installed from the storage medium into the memory unit (19) of the control device (4). As a computer-readable storage medium, it may be any one of, for example, a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), a memory card, RAM (Random Access Memory), ROM (Read Only Memory), and SSD (Solid State Drive), or a combination of two or more of them.

[0022] <Composition of Processing Unit>

[0023] Next, an example configuration of a processing unit (16) mounted on a substrate processing system (1) will be described with reference to FIG. 1b. The processing unit (16) is equipped with a chamber (101), a substrate holding part (102), a cup part (103), a first supply mechanism (140), a second supply mechanism (150), a third supply mechanism (160), a fourth supply mechanism (170), and a nozzle cleaning mechanism (106).

[0024] The substrate holding part (102) is equipped with a main body part (121) in the shape of a disc larger than the wafer (W), a plurality of gripping parts (122) provided on the periphery of the upper surface of the main body part (121), a supporting member (123) that supports the main body part (121), and a driving part (124) that rotates the supporting member (123).

[0025] The substrate holding member (102) holds the wafer (W) by holding the peripheral portion of the wafer (W) using a plurality of gripping members (122). At this time, the wafer (W) is held horizontally while being slightly separated from the upper surface of the main body (121).

[0026] The cup portion (103) is positioned to surround the substrate holding portion (102) and recovers the processing liquid scattered from the wafer (W). At the bottom of the cup portion (103), a drain port (131) for discharging the processing liquid supplied to the wafer (W) to the outside of the chamber (101) and an exhaust port (132) for exhausting the atmosphere inside the chamber (101) are formed.

[0027] The first supply mechanism (140), the second supply mechanism (150), and the third supply mechanism (160) supply a processing fluid required for processing to the upper surface (surface) of the wafer (W).

[0028] The first supply mechanism (140) comprises a first nozzle (141), a first arm (142) that supports the first nozzle (141), and a first pivoting and lifting mechanism (143) that pivots and lifts the first arm (142). By means of the first pivoting and lifting mechanism (143), the first arm (142) can move the first nozzle (141) between a processing position above the wafer (W) (indicated by a dashed line in FIG. 1b) and a standby position outside the wafer (W) (indicated by a solid line in FIG. 1b).

[0029] The first nozzle (141) is formed as a bar nozzle having a length equal to the radius of the wafer (W). When the first nozzle (141) is in the processing position, the longitudinal tip of the first nozzle (141) is located above the center of the wafer (W), and the longitudinal base of the first nozzle (141) is located above the periphery of the wafer (W).

[0030] An example of a processing fluid supply mechanism (200) for a first nozzle that supplies hydrogen peroxide, SPM (Sulfuric Acid Hydrogen Peroxide Mixture, a mixed chemical solution of sulfuric acid and hydrogen peroxide), and vapor as processing fluids to a first nozzle (141) will be described below with reference to FIG. 7.

[0031] The treatment fluid supply mechanism (200) is equipped with a sulfuric acid supply unit (2020), a hydrogen peroxide supply unit (2040), a mixing unit (2050) that mixes sulfuric acid and hydrogen peroxide to produce SPM, and a vapor supply unit (201).

[0032] The sulfuric acid supply unit (2020) is equipped with a tank (2021) for storing sulfuric acid, a circulation path (2022) connected to the tank (2021), and equipment such as a pump (2023), a heater (2024), and a filter (2025) provided in the circulation path (2022). Sulfuric acid is replenished in the tank (2021) as needed from a sulfuric acid supply source (not shown), for example, provided as factory power. A circulation flow of sulfuric acid is formed by the pump (2023), which flows out from the tank (2021) to the circulation path (2022) and returns to the tank (2021). The sulfuric acid circulates within the circulation path (2022) while being heated to a predetermined temperature (for example, about 120°C) by the heater (2024).

[0033] From the circulation path (2022), a number of branch supply paths (sulfuric acid supply paths to each processing unit (16)) (2026) equal to the number of processing units (16) provided in the substrate processing system (1) are branched out, and each branch supply path (2026) is assigned to one chamber (101). Each branch supply path (2026) is provided with a flow meter (2027), a flow control valve (2028), and an opening / closing valve (2029). Between the flow control valve (2028) and the opening / closing valve (2029), a return path (2030) is branched out from the branch supply path (2026). An opening / closing valve (2031) is provided in the return path (2030).

[0034] The hydrogen peroxide supply unit (2040) has a main supply line (2041) connected to a hydrogen peroxide supply source (2043) provided, for example, as factory power. From the main supply line (2041), a number of branch supply lines (2042) (hydrogen peroxide supply lines to each treatment unit (16)) equal to the number of treatment units (16) are branched out, and each branch supply line (2042) is assigned to one treatment unit (16). Each branch supply line (2042) is provided with a flow meter (2045), a flow control valve (2046), and an opening / closing valve (2047). The downstream end of the branch supply line (2042) of the hydrogen peroxide supply unit (2040) joins the branch supply line (2026) for sulfuric acid. This joining section becomes the aforementioned mixing section (2050). The branch supply path (2026) downstream of the mixing section (2050) is also referred to as the ‘chemical supply path (221)’. A temperature sensor (temperature measuring section) (2052) is provided at the downstream end of the chemical supply path (221) (near the connection with the first nozzle (141)). A structure that promotes mixing of sulfuric acid and hydrogen peroxide, such as an inline mixer, may be provided in the mixing section (2050) or in the chemical supply path (221) slightly downstream of the mixing section (2050).

[0035] Between the mixing section (2050) and the opening / closing valve (2029), a drain line (2032) is branched from the branch supply line (2026) for sulfuric acid. An opening / closing valve (2033) is provided in the drain line (2032). This drain line (2032) can be used to discharge SPM remaining in the chemical supply line (221), for example, after the processing of one wafer (W) is finished and before the processing of the next wafer (W) begins.

[0036] As is evident from the piping system diagram of FIG. 7, by supplying only hydrogen peroxide solution without supplying sulfuric acid to the mixing section (2050), hydrogen peroxide that does not contain sulfuric acid can be supplied to the first nozzle (141). Additionally, by supplying both sulfuric acid and hydrogen peroxide solution to the mixing section (2050), SPM can be supplied to the first nozzle (141).

[0037] The vapor supply unit (201) is equipped with a steam generator or a mist generator and can supply a fluid containing steam or mist of pressurized DIW (pure water) (hereinafter also referred to as 'vapor' for simplification of description) to a first nozzle (141) through a supply path (211) in which an opening / closing valve (212) is provided.

[0038] The second supply mechanism (150) is equipped with three nozzles (151A, 151B, 151C) (collectively referred to as the "second nozzles"), a second arm (152) that supports and moves the second nozzles (151A, 151B, 151C), and a second pivoting and lifting mechanism (153) that pivots and raises the second arm (152). The second arm (152) can move the second nozzles (151A, 151B, 151C) between a groove position (waiting position) outside the periphery of the wafer (W) and a processing position above the wafer (W). The second nozzle (151A) supplies an inert gas, such as nitrogen (N2) gas, to the surface of the wafer (W). The second nozzle (151B) supplies a replacement solution, in this case, IPA (isopropyl alcohol) as an example, to the surface of the wafer (W). The second nozzle (151C) selectively supplies either DHF (dilute hydrofluoric acid) or DIW at room temperature to the surface of the wafer (W).

[0039] The third supply mechanism (160) is equipped with two nozzles (161A, 161B) (collectively referred to as the "third nozzle"), a third arm (162) that supports and moves the third nozzles (161A, 161B), and a third pivoting and lifting mechanism (163) that pivots and raises the third arm (162). The third arm (162) can move the third nozzles (161A, 161B) between a groove position (waiting position) outside the periphery of the wafer (W) and a processing position above the wafer (W). The third nozzle (161A) selectively supplies one of SC1 (a mixed solution of ammonia water, hydrogen peroxide water, and water), hydrogen peroxide water, heated DIW (HDIW), and room temperature DIW to the surface of the wafer (W). The third nozzle (161B) supplies two fluids, which are a mixture of atomized DIW and an inert gas (e.g., nitrogen gas), to the wafer (W).

[0040] The fourth supply mechanism (170) supplies a processing fluid necessary for processing to the lower surface (back surface) of the wafer (W). As schematically shown in FIG. 2, the fourth supply mechanism (170) has three nozzles (171A, 171B, 171C) (these are collectively referred to as the ‘fourth nozzles’). In one embodiment, the support member (123) of the substrate holding member (102) is formed hollow, and a narrow, long cylindrical member is inserted into this hollow. A plurality of fluid passages extending in the vertical direction are formed in the cylindrical member. Each fluid passage has an opening end that opens toward the approximately center of the lower surface of the wafer (W), and this opening end becomes the fourth nozzle (171A, 171B, 171C). The fourth nozzle (171A) selectively discharges either DHF or DIW at room temperature. The fourth nozzle (171B) discharges HDIW (heated DIW). The fourth nozzle (171C) discharges an inert gas (here, nitrogen gas (also referred to as N2 gas)).

[0041] Although omitted, each nozzle of the second supply mechanism (150), the third supply mechanism (160), and the fourth supply mechanism (170) is connected to a supply source of a treatment fluid (chemical solution such as sulfuric acid, hydrogen peroxide, DIW, inert gas, etc.) via a supply line (pipeline). The treatment fluid supply source may be provided as factory power, or it may be a tank, a cylinder, etc. that stores the treatment fluid. Each supply line is equipped with a flow control device including an opening / closing valve, a flow control valve, a flow meter, etc., and is configured so that the treatment fluid can be supplied to the corresponding nozzle at a controlled flow rate through each supply line. For nozzles that discharge multiple types of treatment fluids, such as the third nozzle (161A), multiple supply lines are connected, each equipped with a flow control device, and are configured so that any one of the multiple supply lines can be connected to the nozzle by means of a switching valve device (e.g., composed of multiple opening / closing valves). In the case where the nozzle is a two-fluid nozzle, such as the third nozzle (161B), a liquid supply line and a gas supply line are connected to the nozzle, and a flow control device is provided for each of these lines. Since the configuration of the supply source and supply line of the second supply mechanism (150), the third supply mechanism (160), and the fourth supply mechanism (170) is well known in the technical field of semiconductor manufacturing devices, the above detailed description is omitted.

[0042] A nozzle cleaning mechanism (106) is provided at the standby position of the first nozzle (141). The nozzle cleaning mechanism (106) cleans the first nozzle (141).

[0043] <Composition of the 1st Nozzle>

[0044] Next, the configuration of the first nozzle (141) will be described in detail with reference to FIGS. 3 to 6. FIG. 3 is a cross-sectional view of the first nozzle (141) according to one configuration example, cut along a plane perpendicular to the longitudinal direction. FIG. 4 is a cross-sectional view in the direction of the arrow along line IV-IV shown in FIG. 3. FIG. 5 is a cross-sectional view in the direction of the arrow along line VV shown in FIG. 3. FIG. 6 is a schematic plan view of the first nozzle (141) according to the first embodiment, viewed from below. In FIG. 6, the area where the vapor flows is indicated by a dot.

[0045] As shown in FIG. 3, the first nozzle (141) comprises a nozzle body (41), two first distribution channels (42), one second distribution channel (43), and a plurality of discharge channels (44) (see FIG. 4 and FIG. 5). Additionally, the first nozzle (141) comprises a plurality of first discharge ports (45) and a plurality of first discharge channels (46) (see FIG. 4), and a plurality of second discharge ports (47) and a plurality of second discharge channels (48) (see FIG. 5).

[0046] The first distribution path (42) and the second distribution path (43) are formed inside the nozzle body (41). As shown in FIGS. 4 and 5, the first distribution path (42) and the second distribution path (43) extend along the longitudinal direction of the nozzle body (41). The first distribution path (42) is connected to the vapor supply unit (201) via the vapor supply path (211). Additionally, the second distribution path (43) is connected to the liquid medicine supply path (221).

[0047] As shown in FIG. 3, the second distribution channel (43) is positioned on the centerline (a line that bisects the nozzle body (41) left and right) when viewed in cross-section of the nozzle body (41). Additionally, two first distribution channels (42) are positioned one on each side of the centerline when viewed in cross-section of the nozzle body (41).

[0048] A plurality of outlet passages (44) are located below the second distribution passage (43). As shown in FIGS. 3 to 5, the plurality of outlet passages (44) are flow paths provided in the lower part of the nozzle body (41) and extend downward in the vertical direction. The plurality of outlet passages (44) are arranged, for example, at equal intervals along the length direction of the nozzle body (41). Adjacent outlet passages (44) are separated by a partition wall. The cross-sectional shape of the outlet passages (44) is, for example, a rectangular shape. The cross-sectional shape of the outlet passages (44) may be circular or elliptical, etc.

[0049] The first discharge port (45) is opened on the inner side of the discharge path (44). Additionally, the second discharge port (47) is positioned above the first discharge port (45) and is opened on the upper side of the discharge path (44). As shown in FIGS. 4 and 5, a plurality of first discharge ports (45) and a plurality of second discharge ports (47) are arranged, for example, at equal intervals along the longitudinal direction of the nozzle body (41). The plurality of first discharge ports (45) and a plurality of second discharge ports (47) are arranged so as to be approximately aligned in the radial direction of the wafer (W) located below the first nozzle (141) when the first nozzle (141) is positioned at the processing position.

[0050] As shown in FIGS. 3 to 6, the first nozzle (141) is provided with a plurality of first discharge ports (45) and a plurality of second discharge ports (47), and also has a plurality of outlet passages (44) communicating with two first discharge ports (45) and one second discharge port (47). Furthermore, the number of first discharge ports (45) and second discharge ports (47) communicating with one outlet passage (44) is not limited to the number shown in FIGS. 3 to 6. That is, the first nozzle (141) may be provided with a plurality of outlet passages (44) communicating with at least one first discharge port (45) and at least one second discharge port (47).

[0051] A plurality of first discharge ports (45) are connected to a first distribution path (42) via a plurality of first discharge paths (46). Additionally, a plurality of second discharge ports (47) are connected to a second distribution path (43) via a plurality of second discharge paths (48).

[0052] Vapor supplied from the vapor supply unit (201) to the first distribution channel (42) is distributed from the first distribution channel (42) to a plurality of first discharge channels (46) and discharged from a plurality of first discharge ports (45) to corresponding plurality of discharge channels (44). Additionally, a chemical solution (hydrogen peroxide or SPM) supplied from the chemical solution supply channel (221) to the second distribution channel (43) is distributed from the second distribution channel (43) to a plurality of second discharge channels (48) and discharged from a plurality of second discharge ports (47) to corresponding plurality of discharge channels (44).

[0053] The vapor discharged from the first discharge port (45) and the liquid discharged from the second discharge port (47) are mixed near the top, which is the inlet of the discharge path (44), and discharged toward the wafer (W) from the bottom, which is the outlet of the discharge path (44).

[0054] As shown in FIG. 6, the second discharge port (47) is positioned on the same axis as the discharge path (44) when viewed from a planar view. The second discharge port (47) discharges the liquid medicine in a direction along the central axis of the discharge path (44) (i.e., the Z-axis direction). The first discharge port (45) is positioned toward a location deviating from the central axis of the discharge path (44) when viewed from a planar view. The first discharge port (45) discharges vapor toward a location deviating from the central axis of the discharge path (44) when viewed from a planar view. As a result, the vapor that collides with the inner surface of the discharge path (44) mixes with the liquid medicine discharged from the second discharge port (47) while forming a swirling flow of vapor within the discharge path (44). In order to form a swirling flow of vapor within the discharge passage (44), the vapor discharged from the first discharge port (45) flows along the inner surface of the discharge passage (44).

[0055] According to the first nozzle (141) having the described configuration, the vapor and the liquid medicine can be efficiently mixed, and the temperature of the liquid medicine can be efficiently increased.

[0056] Additionally, as shown in FIG. 6, the central axis of the first discharge port (45) is inclined with respect to the direction of the normal (N) of the inner surface of the discharge path (44) when viewed from a plane. By inclining the central axis of the first discharge port (45) with respect to the direction of the normal (N), it is easier to form a swirling flow of vapor within the discharge path (44) compared to when the central axis of the first discharge port (45) is perpendicular to the inner surface of the discharge path (44). Furthermore, since the residence time of the vapor within the discharge path (44) can be extended by the swirling flow, the amount of vapor used to mix the vapor and the liquid medicine can be reduced.

[0057] The configuration of the first nozzle (141) is preferably as shown in FIGS. 3 to 6, but is not limited thereto. It is sufficient if the first nozzle (141) is configured such that after the vapor and the liquid medicine are mixed approximately uniformly within the first nozzle (141), the mixed fluid of the vapor and the liquid medicine is discharged from the first nozzle (141) to the wafer (W).

[0058] As is evident from the piping system diagram of FIG. 7, by supplying only hydrogen peroxide solution without supplying sulfuric acid to the mixing section (2050), hydrogen peroxide that does not contain sulfuric acid is supplied to the first nozzle (141) as a chemical solution. Additionally, by supplying both sulfuric acid and hydrogen peroxide solution to the mixing section (2050), SPM, which is a mixed chemical solution of sulfuric acid and hydrogen peroxide, is supplied to the first nozzle (141) as a chemical solution.

[0059] A nozzle known in the technical field of semiconductor manufacturing equipment may be used as a nozzle other than the first nozzle (141). The illustration and description of the structure of such a nozzle are omitted.

[0060] Processing performed in the processing unit

[0061] Next, the processing performed on the wafer within the processing unit (16) will be explained with reference to the schematic side views of FIGS. 8 to 10. The processing described below is also performed under the control of the control device (4) shown in FIG. 1a.

[0062] Incoming Process

[0063] First, the wafer (W) is brought in and processed. Specifically, the substrate transport device (17) of the transport unit (15) brings the wafer (W) into the processing unit (16), and the wafer (W) is held by the substrate holding unit (102). The wafer (W) to be processed is, for example, one having an oxide film or a nitride film formed on its surface, and the materials to be removed from the surface of the wafer (W) by a series of processes are organic materials such as resist residue and abrasives.

[0064] After this, the substrate holding part (102) begins to rotate at a predetermined rotational speed. The wafer (W) continues to rotate until a series of processes are completed on one wafer (W) (the rotational speed is appropriately changed as needed). In addition, unless specifically noted otherwise, when liquid is supplied to the back side (bottom side) of the wafer (W), a small amount of N2 gas is constantly discharged from the fourth nozzle (171C).

[0065] Natural Oxide Removal Process

[0066] As shown in FIG. 8 (a), the second nozzle (151C) is positioned directly above the center of the rotating wafer (W), and DHF is discharged from the second nozzle (151C) to adhere to the center of the wafer (W).

[0067] DHF flows and diffuses toward the periphery of the wafer (W) by centrifugal force and scatters outward from the wafer. As a result, the entire surface of the wafer (W) is covered by a liquid film of DHF. The natural oxide film formed on the surface of the wafer (W) is removed by the DHF supplied in this manner. Additionally, it is preferable to position the second nozzle (151C) directly above a position radially outward from the center of rotation of the wafer (W) (provided that the entire surface of the wafer (W) is guaranteed to be covered by DHF). By doing so, it is possible to prevent the center of rotation of the wafer (W) from being significantly etched locally.

[0068] When heated DHF is supplied to the surface of the wafer (W), DHF is discharged from the fourth nozzle (171A) toward the center of the wafer (W) on the back side of the wafer (W). This DHF also flows toward the outside of the wafer while covering the entire back side of the wafer (W), thereby removing the natural oxide film formed on the back side of the wafer (W).

[0069] The chemical solution used in the process of removing the natural oxide film is, for example, dilute hydrofluoric acid (DHF) with a concentration of about 1%, but in addition to DHF, a treatment solution containing hydrofluoric acid such as BHF may also be used.

[0070] Rinse Process (Rinse Process after DHF)

[0071] At the end of the natural oxide film removal process, the second nozzle (151C) discharging DHF is positioned directly above the center of the wafer (W) (see FIG. 8(b)), and then the processing fluid discharged from the second nozzle (151C) and the fourth nozzle (171A) is switched from DHF to DIW (see FIG. 8(c)), and the process proceeds to the rinsing process. The discharge of DIW from the fourth nozzle (171A) may continue throughout the rinsing process, but may be stopped for a few seconds in the middle.

[0072] Next, the second nozzle (151C) that is discharging DIW is moved to a position radially outward from the center of rotation of the wafer (W), and the third nozzle (161A) is moved to a position radially outward from the center of rotation of the wafer (W) on the opposite side from the second nozzle (151C) (see FIG. 9 (a)). The second nozzle (151C) and the third nozzle (161A) are positioned so that the entire surface of the wafer (W) is guaranteed to be covered with DIW. Furthermore, the replacement of the nozzle discharging DIW is not strictly necessary in the subsequent sequence, provided that no interference occurs between the arms or nozzles.

[0073] Next, the second nozzle (151C) that is discharging DIW is moved toward the home position (waiting position) (refer to the arrow in FIG. 9 (b)). When the second nozzle (151C) is outward from the periphery of the wafer (W) when viewed from a plane, the discharge of DIW from the second nozzle (151C) is stopped. Along with this movement of the second nozzle (151C), the third nozzle (161A) that is discharging DIW is moved directly up to a position radially outward from the center of rotation of the wafer (W), and is stopped at that position. The position of the third nozzle (161A) at this time is a position that ensures it does not interfere with the first nozzle (141) when the first nozzle (141) is subsequently positioned at the processing position above the wafer (W), and is also a position as close as possible to the center of rotation of the wafer (W) to ensure that the entire wafer (W) is covered with a liquid film of DIW.

[0074] Next, while continuing to discharge DIW from the third nozzle (161A), the first nozzle (141) is positioned at the processing position (see FIG. 9 (c)), and thereafter, only vapor (not containing sulfuric acid or hydrogen peroxide) is discharged from the first nozzle (141) (see FIG. 9 (d)). The discharge of vapor from the first nozzle (141) is performed by opening the shut-off valve (212) shown in FIG. 7.

[0075] The discharge of vapor from the first nozzle (141) is not intended to enhance the rinsing effect, but is performed to discharge condensed water (DIW) within the first nozzle (141) and the conduit connected thereto. The discharge of vapor from the first nozzle (141) can also be described as a dummy dispense from the first nozzle (141) onto the wafer (W). Subsequently, when mist and reactive liquid (hydrogen peroxide, SPM, etc.) are discharged from the first nozzle (141), if condensed water falls as droplets, there is a possibility that an undesirable reaction may occur. However, if vapor discharge from the first nozzle (141) is performed during the rinsing process in which the entire surface of the wafer (W) is covered with a liquid film of water (DIW), no problem occurs even if water droplets fall onto the wafer (W). In addition, there is a possibility that the water droplets contain particle-causing substances, but since the water droplets fall onto the liquid film of DIW and then immediately detach from the surface of the wafer (W), there is no risk of the wafer (W) being contaminated.

[0076] Discharging only vapor without accompanying the discharge of hydrogen peroxide from the first nozzle (141) can be done for a short period of time, for example, 1 to 5 seconds, which is sufficient to discharge the condensation water inside the first nozzle (141) and the conduit connected thereto.

[0077] Oxide film formation process

[0078] Next, the discharge of DIW from the third nozzle (161A) is continued, and while the discharge of vapor from the first nozzle (141) is continued without stopping, hydrogen peroxide is supplied to the first nozzle (141) (without supplying sulfuric acid) (see FIG. 10 (a)). The supply of hydrogen peroxide to the first nozzle (141) is performed by opening the shut-off valve (2047) shown in FIG. 7. After being mixed with vapor inside the first nozzle (141), the hydrogen peroxide becomes a mixed fluid in a mist state and is discharged onto the wafer (W). The mixed fluid falls onto a liquid film of DIW covering the entire wafer (W), mixes with this DIW, flows over the wafer (W), and flows outward from the wafer (W).

[0079] Almost simultaneously with the initiation of the supply of hydrogen peroxide to the first nozzle (141), the discharge of DIW from the fourth nozzle (171A) is stopped, and the discharge of HDIW heated to, for example, a temperature of about 70 to 80°C is also initiated from the fourth nozzle (171B) (see FIG. 10(b)). By doing so, the temperature of the wafer (W) rises, and the oxidation reaction by hydrogen peroxide on the surface of the wafer (W) is promoted. In addition, the time during which the discharge of hydrogen peroxide and vapor from the first nozzle (141) and the discharge of DIW from the fourth nozzle (171A) are carried out simultaneously is, for example, about 5 to 15 seconds.

[0080] Next, the third nozzle (161A) that is discharging DIW is moved toward the home position (waiting position) (scan out of the third nozzle (161A)). At this time, it may stop at a position radially outward from the center of rotation of the wafer (W) (for example, a position about 2 / 3 of the radius of the wafer (W)), and then the third nozzle (161A) may be scan out.

[0081] When the third nozzle (161A) extends outward from the periphery of the wafer (W) when viewed from a planar perspective, the discharge of DIW from the third nozzle (161A) is stopped (see (c) of FIG. 10). As a result, only a mixed fluid of hydrogen peroxide and vapor is supplied to the surface of the wafer (W) from the first nozzle (141). This state is maintained for a predetermined time (e.g., from 50 seconds to about 100 seconds). As a result, a chemical oxide film is uniformly formed over the entire surface of the wafer (W). Furthermore, the term "chemical oxide film" refers to an oxide film formed using an oxidizing chemical solution, and in this respect, it differs from a "natural oxide film."

[0082] The chemical oxide film formed using the chemical solution is more uniform than the natural oxide film and has uniform hydrophilicity. In addition, as described above, by first supplying a mixed fluid of DIW, hydrogen peroxide, and vapor, and then stopping the supply of DIW and supplying only the mixed fluid of hydrogen peroxide and vapor, a chemical oxide film can be formed uniformly without causing non-uniformity in processing. The SPM permeates well into the surface of the wafer (W) where the chemical oxide film is uniformly formed and has become hydrophilic (the wettability of the SPM is high). Because of this, the reaction between the SPM and the substance to be removed is initiated quickly, so the processing time can be shortened. In addition, since non-uniform wetting of the SPM does not occur, SPM processing with high uniformity within the plane can be performed, and the generation of particles caused by non-uniform wetting can be prevented.

[0083] As in the present embodiment, by discharging hydrogen peroxide solution into the wafer (W) in the form of a mixed fluid with vapor, the temperature of the hydrogen peroxide solution rises and the oxidation ability increases, so a chemical oxide film of sufficient thickness can be formed in a short time.

[0084] Referring to FIG. 11, an example of experimental results confirming the effect of mixing vapor with hydrogen peroxide solution in the oxide film formation process is described. The test was performed using a processing unit (16) having a configuration corresponding to that shown in FIG. 1a. A bare silicon wafer having a natural oxide film formed on its surface was prepared, and the natural oxide film removal process, rinsing process, and oxide film formation process described above were performed sequentially on it, followed by a pure rinsing and brushing drying (the above is an experimental example). As a comparative example, a treatment was performed on a bare silicon wafer that differed only in that vapor was not mixed with hydrogen peroxide solution in the oxide film formation process. For the experimental example and the comparative example, the thickness of the chemical oxide film formed on the surface of the wafer was measured. In the natural oxide film removal process, room temperature DHF with a concentration of 1% was used. In the oxide film formation process, room temperature hydrogen peroxide solution was used.

[0085] Figure 11 shows the relationship between the processing time of the oxide film formation process (discharge time of hydrogen peroxide solution) and the thickness of the chemical oxide film formed on the surface of the wafer (W). It can be seen that when vapor is mixed with the hydrogen peroxide solution (plot of ●), a chemical oxide film of sufficient thickness is formed in less than 1 / 3 of the time compared to when vapor is not mixed (plot of ■).

[0086] <SPM 처리 공정>

[0087] Next, the rotation speed of the wafer (W) is reduced, and then sulfuric acid is supplied to the first nozzle (141) from which a mixed fluid of hydrogen peroxide and vapor is discharged. As a result, a mixed fluid of SPM and vapor (SPM+Vapor) is discharged from the first nozzle (141) onto the surface of the wafer (W) (see FIG. 10 (d)), and the hydrogen peroxide covering the surface of the wafer (W) is replaced by the SPM. The removal target attached to the surface of the wafer (W) is removed by this SPM. As is known in the prior art, by mixing vapor with the SPM, the reactivity between the SPM and the surface of the wafer (W) is increased, thereby promoting etching.

[0088] The reason for reducing the rotation speed of the wafer (W) before the start of SPM discharge from the first nozzle (141) (i.e., before the start of mixing sulfuric acid) is to minimize the droplets of SPM scattered to the outside of the cup portion (103) and to prevent contamination within the chamber (16). After the SPM treatment process is started, the discharge of HDIW from the fourth nozzle (171B) is stopped.

[0089] The transition from the oxide film formation process to the SPM treatment process is specifically carried out as follows. That is, from a state where hydrogen peroxide is supplied to the first nozzle (141) through the branch supply line (2026), the mixing section (2050), and the chemical supply line (221) with the opening / closing valve (2047) open, the opening / closing valve (2029) is also opened. Then, sulfuric acid flows from the branch supply line (2026) into the mixing section (2050), and in the mixing section (2050), sulfuric acid and hydrogen peroxide are mixed to produce SPM, which is then supplied to the first nozzle (141) through the chemical supply line (221).

[0090] The supply flow rate of hydrogen peroxide may be changed before and after the opening operation of the shut-off valve (2029).

[0091] In the transition from the oxide film formation process to the SPM treatment process, while the supply of vapor to the first nozzle (141) continues, the chemical solution (treatment fluid) supplied from the chemical solution supply line (221) to the first nozzle (141) is switched from hydrogen peroxide to SPM. Since the supply of vapor to the first nozzle (141) is not interrupted and the supply of hydrogen peroxide to the first nozzle (141) is not interrupted, the switching of the treatment fluid supplied to the first nozzle (141) is performed without interruption.

[0092] In this way, by not interrupting or stopping the supply of the processing fluid to the first nozzle (141) or by minimizing it as much as possible, the occurrence of fluid flow cessation or stagnation within the first nozzle (141) and the piping connected thereto is minimized. As a result, the condition of the fluid supplied to the first nozzle (141) is stabilized, and the cleanliness level can also be maintained at a high level. In addition, since the number of opening and closing operations of the shut-off valve can be minimized, the generation of particles associated with the opening and closing operation of the shut-off valve can also be suppressed. Therefore, high-quality processing can be performed.

[0093] In addition, in the above series of steps (rinse process after DHF → oxide film formation process → SPM treatment process), a liquid film of DIW → a liquid film of a mixture of DIW and hydrogen peroxide → a liquid film of hydrogen peroxide → a liquid film of SPM are sequentially formed on the surface of the wafer (W). There is no problem even if hydrogen peroxide falls on the liquid film of DIW, and there is no problem even if SPM falls on the liquid film of hydrogen peroxide. That is, according to the above series of steps, the liquid film existing on the surface of the wafer (W) can be transferred without any problems.

[0094] It is assumed that the sequence in which SPM is applied onto the liquid film of DIW (e.g., oxide film formation treatment → DIW rinse → SPM treatment) is assumed. In this case, when SPM is applied onto the liquid film of DIW, localized bumps may occur, raising concerns about contamination within the processing unit or the generation of particle-causing substances. Therefore, when performing SPM treatment following DIW treatment, it is necessary to first remove the DIW by shaking it off the wafer (W), for example, and then supply SPM to the wafer (W). Doing so increases the processing time per wafer. Furthermore, drying the surface of the wafer (W) during the series of treatments is undesirable from the perspective of preventing particle generation. However, in the above sequence according to the embodiment, such problems do not occur.

[0095] <Rinsing Process (Rinsing Process after SPM)>

[0096] After performing the SPM treatment process over a predetermined period of time, the third nozzle (161A) is positioned slightly away from the center of rotation of the wafer, and in this state, the discharge of the mixed fluid of SPM and vapor from the first nozzle (141) is stopped. Subsequently, the rotation speed of the wafer (W) is increased, and DIW as a rinse liquid is discharged from the third nozzle (161A), and a rinse treatment is performed. Also, at this time, DIW falls onto the liquid film of SPM, but since the wafer (W) is rotating, the liquid film of SPM is thin, so even if DIW falls there, no problem occurs due to the mixing of SPM and DIW.

[0097] The rinse liquid supplied to the wafer (W) flows and spreads toward the periphery of the wafer (W) due to the centrifugal force accompanying the rotation of the wafer (W), and is scattered to the outside of the wafer (W). As a result, any remaining SPM on the wafer (W) is washed away by the rinse liquid. During the rinse process, the position where the rinse liquid is applied may be moved between the center of the wafer and the periphery of the wafer. The first nozzle (141), which has stopped discharging the mixed fluid, is returned to the home position (waiting position) and is cleaned by the nozzle cleaning mechanism (106). A two-fluid rinse process may be performed prior to the rinse process.

[0098] <Substitution Process>

[0099] Next, a replacement solution (IPA) is supplied to the center of the surface of the wafer (W) from the second nozzle (151B) for supplying the replacement solution. The replacement solution supplied to the wafer (W) flows and diffuses toward the periphery of the wafer (W) due to the centrifugal force accompanying the rotation of the wafer (W), thereby replacing the rinse solution remaining on the wafer (W) with the replacement solution.

[0100] Drying Process

[0101] Next, with the discharge of the replacement liquid from the second nozzle (151B) stopped, the rotation speed of the wafer (W) is increased. By doing so, the replacement liquid remaining on the wafer (W) is shaken off, and the wafer (W) is dried. After that, the rotation of the wafer (W) is stopped.

[0102] The replacement process and the drying process may be performed simultaneously. Specifically, for example, nitrogen gas may be discharged from the second nozzle (151A) and IPA may be discharged from the second nozzle (151B), and the second nozzles (151A, 151B) may be moved radially outward so that the second nozzle (151A) discharging nitrogen gas is located radially inward than the second nozzle (151B) discharging IPA.

[0103] <Outbound Process>

[0104] Next, a release process is performed. In the release process, the substrate return device (17) of the return unit (15) releases the wafer (W) held in the substrate holding unit (102) out of the processing unit (16). By doing so, a series of processes performed on one wafer (W) in relation to the processing unit (16) is completed.

[0105] In addition, after the above rinsing process, after performing the desired chemical treatment (e.g., SC1 treatment, SC2 treatment, etc.) and rinsing treatment, it is acceptable to perform the substitution process and the drying process.

[0106] The embodiments disclosed herein should be considered as illustrative and not limiting in all respects. The above embodiments may be omitted, substituted, or modified in various forms without departing from the scope and common knowledge of the appended claims.

[0107] The substrate to be processed is not limited to semiconductor wafers, and may be any type of substrate used in the technical field of semiconductor device manufacturing, such as glass substrates and ceramic substrates.

Claims

Claim 1 A substrate treatment method comprising: a first process of discharging a treatment solution containing hydrofluoric acid onto the surface of a substrate; a second process of discharging a rinse solution onto the surface of the substrate after the first process; and a third process of discharging a mixed fluid of hydrogen peroxide and pure water vapor or mist onto the surface of the substrate after the second process. Claim 2 A substrate treatment method according to claim 1, wherein the rinse liquid used in the second process is water. Claim 3 A substrate processing method according to claim 1, wherein a heated temperature fluid is supplied to the back surface of the substrate to heat the substrate while the third process is being performed. Claim 4 A substrate treatment method according to claim 3, wherein the temperature-regulating fluid is heated water. Claim 5 A substrate processing method according to claim 1, wherein the third process is initiated before the second process is terminated, and when the third process is initiated, the contact point of the rinse liquid supplied to the surface of the substrate during the second process moves toward the periphery of the substrate and detaches from the substrate. Claim 6 A substrate treatment method according to claim 1, further comprising a fourth process of discharging a mixed fluid of sulfuric acid and hydrogen peroxide (SPM), which is a mixture of sulfuric acid and hydrogen peroxide, and pure water vapor or mist onto the surface of the substrate after the third process. Claim 7 A substrate processing method according to claim 6, wherein the discharge of a mixed fluid of hydrogen peroxide and pure water vapor or mist in the third process and the discharge of a mixed fluid of SPM and pure water vapor or mist in the fourth process are performed using the same mixed fluid nozzle. Claim 8 A substrate processing method according to claim 7, wherein the mixing fluid nozzle used in the third and fourth processes is a bar nozzle having a plurality of discharge ports, and when the longitudinal direction of the bar nozzle is aligned with the radial direction of the substrate, the plurality of discharge ports are aligned with the radial direction of the substrate. Claim 9 A substrate processing method according to claim 7, wherein the nozzle for discharging the rinse liquid used in the second process is a nozzle different from the mixing fluid nozzle used in the third and fourth processes. Claim 10 A substrate treatment method according to claim 7, wherein the transition from the third process to the fourth process is performed by changing the treatment liquid supplied to the mixed fluid nozzle from hydrogen peroxide to SPM while continuously supplying pure steam or mist to the mixed fluid nozzle. Claim 11 A substrate treatment method according to claim 10, wherein changing the treatment liquid supplied to the mixing fluid nozzle from hydrogen peroxide to SPM is performed by adding a flow of sulfuric acid to the flow of hydrogen peroxide without interrupting the flow of hydrogen peroxide toward the mixing fluid nozzle. Claim 12 A substrate processing method according to claim 6, wherein the rotation speed of the substrate is reduced at the end of the third process, and then the process is transitioned from the third process to the fourth process. Claim 13 A substrate processing device comprises: a substrate holding unit for holding a substrate; a hydrofluoric acid-containing processing liquid supply unit for supplying a processing liquid containing hydrofluoric acid to the surface of a substrate; a rinse liquid supply unit for supplying a rinse liquid to the surface of a substrate; a mixed fluid nozzle configured to supply either a fluid containing pure water vapor or mist and hydrogen peroxide to the surface of a substrate, either alone or both simultaneously; a pure water vapor supply unit for supplying a fluid containing pure water vapor or mist to the mixed fluid nozzle; a hydrogen peroxide supply unit for supplying hydrogen peroxide to the mixed fluid nozzle; and a control unit for controlling the operation of the substrate processing device. The control unit controls the operation of the substrate processing device to perform a first process of discharging a processing liquid containing hydrofluoric acid onto the surface of a substrate using the hydrofluoric acid-containing processing liquid supply unit; a second process of discharging a rinse liquid onto the surface of the substrate using the rinse liquid supply unit after the first process; and after the second process, the mixed fluid nozzle, the pure water vapor supply unit, and the hydrogen peroxide A substrate processing apparatus that performs a third process of discharging a mixed fluid of hydrogen peroxide and pure water vapor or mist onto the surface of the substrate using a supply unit. Claim 14 A substrate processing apparatus according to claim 13, further comprising a sulfuric acid supply unit for supplying sulfuric acid to the mixing fluid nozzle, wherein the mixing fluid nozzle is configured to supply at least one of a fluid containing pure water vapor or mist, hydrogen peroxide, and sulfuric acid peroxide (SPM), which is a mixture of hydrogen peroxide and sulfuric acid, to the surface of a substrate, and wherein the control unit controls the operation of the substrate processing apparatus to further perform a fourth process of discharging a mixed fluid of SPM and pure water vapor or mist to the surface of the substrate after the third process. Claim 15 A substrate processing apparatus according to claim 14, wherein the mixing fluid nozzle is a bar nozzle having a plurality of discharge ports, and when the longitudinal direction of the bar nozzle is aligned with the radial direction of the substrate, the plurality of discharge ports are aligned with the radial direction of the substrate. Claim 16 A substrate processing apparatus according to claim 15, further comprising a hydrogen peroxide supply line for sending hydrogen peroxide from a hydrogen peroxide supply source, a sulfuric acid supply line for supplying sulfuric acid from a sulfuric acid supply source, and a chemical supply line for supplying liquid from a mixing section where the hydrogen peroxide supply line and the sulfuric acid supply line merge to the mixing fluid nozzle, wherein the transition from the third process to the fourth process is performed by supplying a fluid containing pure vapor or mist from the pure vapor supply section to the mixing fluid nozzle, while continuing the state in which hydrogen peroxide is supplied from the hydrogen peroxide supply source to the mixing fluid nozzle through the hydrogen peroxide supply line, the mixing section, and the chemical supply line, and also supplying sulfuric acid from the sulfuric acid supply source to the mixing section through the sulfuric acid supply line, thereby mixing hydrogen peroxide and sulfuric acid in the mixing section to produce SPM. Claim 17 A storage medium storing a program, wherein when the program is executed by a control unit of a substrate processing device comprising a computer, the control unit is configured to control the substrate processing device to execute a substrate processing method described in any one of claims 1 to 12.

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