Substrate processing method

Abstract

Provided is a technique that contributes to a reduction in the amount of sulfuric acid used and makes it possible to appropriately remove an organic layer on a substrate. The substrate processing method includes a holding step (S1), a first step (S3), a second step (S4), and a third step (S5). In the holding step (S1), a substrate is held, and an organic layer having a first hardened layer, a non-hardened layer, and a second hardened layer is formed on the main surface of the substrate. In the first step (S3), a mixed solution of sulfuric acid and a hydrogen peroxide solution is supplied to the main surface of the substrate to remove the first hardened layer. And a second step (S4) in which, after the first step (S1), the non-cured layer is removed by supplying, to the main surface of the substrate, a mixed solution obtained by mixing at a mixing ratio that is lower in reactivity than the reactivity of the mixed solution in the first step (S1). And a third step (S5) in which, after the second step (S4), the second hardened layer is removed by supplying, to the main surface of the substrate, a mixed solution obtained by mixing at a mixing ratio having higher reactivity than the reactivity of the mixed solution in the second step (S4).

Description

Technical Field

[0001] The invention relates to a substrate processing method. Background Art

[0002] Conventionally, a single-wafer substrate processing apparatus for removing resist from a substrate has been proposed (e.g., Patent Document 1). In Patent Document 1, the substrate processing apparatus removes the resist by supplying a mixture of sulfuric acid and hydrogen peroxide solution (hereinafter also referred to as SPM solution) to the substrate.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-026489 Summary of the Invention

[0006] Problem to be solved

[0007] The resist includes a hardened layer. For example, a hardened layer and a non-hardened layer are formed in the resist by an impurity injection process in which impurities are injected into the substrate. The hardened layer can be formed not only on the exposed surface side of the resist (referred to as the first hardened layer), but also on the main surface side of the substrate (referred to as the second hardened layer). Therefore, a portion of the second hardened layer can also be formed on the lower side of the non-hardened layer inside the resist. Such first and second hardened layers are more difficult to remove than the non-hardened layer. On the contrary, the non-hardened layer is easier to remove than the first and second hardened layers.

[0008] To remove a resist having a first hardened layer, an unhardened layer, and a second hardened layer, it is not necessarily optimal to always use a highly reactive SPM solution mixed at a concentration. In particular, there is a demand to reduce the amount of sulfuric acid used to reduce environmental impact. To this end, there is still room for research on the concentration of the SPM solution.

[0009] Therefore, an object of the present invention is to provide a technology that contributes to reducing the amount of sulfuric acid used and can appropriately remove an organic layer on a substrate.

[0010] Technical solutions to the problem

[0011] A first method is a substrate processing method for removing an organic layer from a substrate, wherein an organic layer including a first hardened layer, a non-hardened layer, and a second hardened layer is formed on a main surface of the substrate, the substrate processing method comprising: a holding step of holding the substrate; a first step of supplying a mixed liquid of sulfuric acid and a hydrogen peroxide solution to the main surface of the substrate to remove the first hardened layer; a second step of supplying, after the first step, a mixed liquid mixed at a mixing ratio having a lower reactivity than that of the mixed liquid in the first step to the main surface of the substrate to remove the non-hardened layer; and a third step of supplying, after the second step, a mixed liquid mixed at a mixing ratio having a higher reactivity than that of the mixed liquid in the second step to the main surface of the substrate to remove the second hardened layer.

[0012] The second method is a substrate processing method according to the first method, wherein, in at least any one of the first process and the third process, the mixed liquid is supplied to the main surface of the substrate in a droplet state, and in the second process, the mixed liquid is supplied to the main surface of the substrate in a continuous flow state.

[0013] The third method is a substrate processing method according to the second method, wherein, after the third process, there is further provided a finishing SPM process of supplying the mixed liquid to the main surface of the substrate in a continuous flow state, and in the third process, the mixed liquid is supplied to the main surface of the substrate in a droplet state.

[0014] A fourth aspect is the substrate processing method according to any one of the first to third aspects, wherein the sulfuric acid concentration of the mixed liquid in the second step is lower than the sulfuric acid concentration of the mixed liquid in the first step.

[0015] The fifth method is a substrate processing method according to any one of the first to third methods, wherein the sulfuric acid concentration of the mixed liquid in the second process is higher than the sulfuric acid concentration of the mixed liquid in the first process, and in the second process, the sulfuric acid stored in the tank is supplied to the main surface of the substrate through a liquid supply pipe, and the mixed liquid passing through the main surface of the substrate is returned to the tank through a recovery pipe.

[0016] Effects of the Invention

[0017] According to the first method, since a highly reactive mixed solution is used in the first and third steps, the first and second hardened layers can be removed more appropriately. In the second step, the non-hardened layer, which is softer than the first and second hardened layers, is removed. Therefore, even with a mixed solution having a low reactivity ratio, the non-hardened layer can be appropriately removed. Furthermore, since a different mixing ratio can be used in the second step than in the first and third steps, a mixing ratio that reduces the amount of sulfuric acid used can also be used.

[0018] According to the second embodiment, in at least one of the first and third steps, the physical force of the droplets can be applied to the hardened layer. This allows the hardened layer to be appropriately removed. In the second step, since the mixed liquid is supplied to the substrate in a continuous flow, the use of gas to generate droplets is unnecessary, reducing operating costs.

[0019] According to the third aspect, generation of residue in the organic layer can be suppressed.

[0020] According to the fourth aspect, the amount of sulfuric acid used can be reduced.

[0021] According to the fifth aspect, since the mixed liquid with a high sulfuric acid concentration is returned to the tank, the sulfuric acid can be reused, thereby reducing the actual amount of sulfuric acid used. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a plan view schematically showing an example of the configuration of a substrate processing apparatus.

[0023] Figure 2 It is a cross-sectional view schematically showing an example of a partial configuration of a substrate.

[0024] Figure 3 This is a block diagram schematically showing an example of the configuration of a control unit.

[0025] Figure 4 This is a diagram schematically showing an example of the configuration of the processing unit according to the first embodiment.

[0026] Figure 5 This is a flowchart showing an example of substrate processing.

[0027] Figure 6 This is a diagram schematically showing an example of the state of the processing unit in each step.

[0028] Figure 7 This is a graph showing an example of temporal changes in the first flow rate of sulfuric acid, the second flow rate of the hydrogen peroxide solution, and the sulfuric acid concentration of the SPM liquid.

[0029] Figure 81 and 2 are diagrams showing an example of a partial configuration of the substrate W after each step.

[0030] Figure 9 This is a diagram showing a first example of the configuration of the processing unit 1 according to the second embodiment.

[0031] Figure 10 This is a diagram schematically showing an example of the state of the processing unit in each step.

[0032] Figure 11 This is a timing chart showing an example of the operation of the processing unit.

[0033] Figure 12 This is a diagram showing a second example of the configuration of the processing unit 1 according to the second embodiment. DETAILED DESCRIPTION

[0034] The following describes the embodiments in detail with reference to the accompanying drawings. In the accompanying drawings, the dimensions and numbers of various components may be exaggerated or simplified as necessary to facilitate understanding. Components with identical configurations and functions are denoted by the same reference numerals, and any duplicate descriptions will be omitted in the following description.

[0035] In the following description, the same components are denoted by the same reference numerals and have the same names and functions, and detailed description thereof may be omitted to avoid redundancy.

[0036] In the following description, even when ordinal numbers such as "first" or "second" are used, these terms are used for convenience to facilitate understanding of the contents of the implementation methods and are not limited to the order that can be generated by these ordinal numbers.

[0037] When expressions expressing relative or absolute positional relationships (e.g., "in a direction," "along a direction," "parallel," "orthogonal," "center," "concentric," "coaxial," etc.) are used, unless otherwise specified, these expressions not only express a strict positional relationship but also express a state of relative displacement by angle or distance within a tolerance or range that achieves the same degree of functionality. When expressions expressing equality (e.g., "same," "equal," "homogeneous," etc.) are used, unless otherwise specified, these expressions not only express a state of strict quantitative equality but also express a state of difference within a tolerance or range that achieves the same degree of functionality. When expressions expressing shape (e.g., "quadrilateral" or "cylindrical") are used, unless otherwise specified, these expressions not only express a strict geometric shape but also express a range that achieves the same degree of effect, such as a shape having concavities and convexities, chamfers, etc. When expressions expressing "disposed," "equipped," "equipped," "including," or "having" a component are used, these expressions are not exclusive expressions that exclude the presence of other components. When the expression "at least any one of A, B, and C" is used, the expression includes only A, only B, only C, any two of A, B, and C, and all of A, B, and C.

[0038] <First embodiment>

[0039] <Overall Structure of Substrate Processing Equipment>

[0040] Figure 1 1 is a top view schematically showing an example of the structure of the substrate processing device 100. The substrate processing device 100 is a single-wafer processing device that processes substrates W piece by piece. The substrate W has a plate-like shape. The substrate W is, for example, a semiconductor substrate and has a circular plate shape. Although the size of the substrate W is not particularly limited, its diameter is, for example, about 300 mm. Furthermore, the substrate W is not necessarily limited to a semiconductor substrate, and various substrates such as 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 disc, a substrate for a magnetic disk, and a substrate for a magneto-optical disc can be applied to the substrate W. In addition, the shape of the substrate is not limited to a circular plate shape, and various shapes such as a rectangular plate shape can be applied.

[0041] Figure 2 This is a cross-sectional view schematically showing an example of a partial structure of a substrate W. A pattern PT and a resist layer R are formed on the main surface of the substrate W. The pattern PT is a pattern for forming a semiconductor device and can be formed of various layers. The resist layer R is an organic layer. Figure 2In the example of FIG, one pattern PT is covered with the resist layer R. These patterns PT and the resist layer R are formed on the main surface of the substrate W by a resist forming apparatus (not shown) before being transported to the substrate processing apparatus 100 .

[0042] Before the substrate W is transported to the substrate processing apparatus 100, impurities are implanted into the substrate W using an impurity implantation apparatus (not shown). This impurity implantation process involves high-energy, high-current ion implantation or plasma doping. This impurity implantation process partially degrades the resist layer R of the substrate W, forming a first hardened layer Ra, an unhardened layer Rb, and a second hardened layer Rc within the resist layer R. In other words, the resist layer R consists of the first hardened layer Ra, the unhardened layer Rb, and the second hardened layer Rc.

[0043] The first hardened layer Ra is mainly the portion on the surface side exposed in the resist layer R and is hardened by the impurity injection process. Figure 2 In the example, the non-hardened layer Rb is the internal part of the resist R and is almost not hardened. The second hardened layer Rc is the part of the resist R that is lower than the first hardened layer Ra, and a part of it is also located directly below the non-hardened layer Rb. The second hardened layer Rc is also the part that is hardened by the impurity injection process. In this structure, the second hardened layer Rc is located lower than the first hardened layer Ra (substrate W side), and at least a part of the upper surface of the second hardened layer Rc (the surface opposite to the substrate W) is covered by the non-hardened layer Rb. In addition, the upper surface of the non-hardened layer Rb (the surface opposite to the substrate W) is covered by the first hardened layer Ra, and the side surfaces of the non-hardened layer Rb are covered by the first hardened layer Ra and the second hardened layer Rc. The first hardened layer Ra and the second hardened layer Rc are harder than the non-hardened layer Rb and are not easy to remove.

[0044] The substrate processing apparatus 100 performs an organic matter removal process to remove the resist layer R of the substrate W. Figure 1 In the example shown, the substrate processing apparatus 100 includes a loading area 110, a processing area 120, and a control unit 90. The loading area 110 serves as an interface for loading and unloading substrates W between the processing area 120 and the outside. The processing area 120 primarily processes the substrates W received from the loading area 110. The control unit 90 is responsible for overall control of the substrate processing apparatus 100.

[0045] <Loading area 110>

[0046] At Figure 1In the example shown in FIG, the loading area 110 includes a plurality of load ports 111 and an indexing robot 112. Each load port 111 holds a substrate container (hereinafter referred to as a carrier C) brought in from the outside. A plurality of substrates W are accommodated in the carrier C in a state of being arranged in a vertical direction. The indexing robot 112 is a transport unit that transports the substrates W between the carrier C and the processing area 120. The indexing robot 112 sequentially removes unprocessed substrates W from the carrier C and transports the substrates W to the processing area 120. In addition, the indexing robot 112 sequentially receives processed substrates W processed in the processing area 120 from the processing area 120 and accommodates the substrates W in the carrier C. The carrier C containing the processed substrates W is unloaded from the load port 111 to the outside.

[0047] <Processing area 120>

[0048] At Figure 1 In the example of FIG, the processing area 120 includes one or more processing units 1 and a central robot 122. Figure 1 In the example shown, the processing area 120 includes a plurality of processing units 1. The central robot 122 is a transport unit that transports substrates W between the index robot 112 and the processing units 1. The central robot 122 transports unprocessed substrates W from the index robot 112 into the processing units 1 and removes processed substrates W from the processing units 1. The central robot 122 transfers substrates W to other processing units 1 as needed and then hands them over to the index robot 112.

[0049] Each processing unit 1 is a single-wafer device that processes each substrate W. An example of a specific configuration of the processing unit 1 will be described in detail below.

[0050] <Control Unit 90>

[0051] The control unit 90 generally controls the substrate processing apparatus 100 . Specifically, the control unit 90 controls the index robot 112 , the center robot 122 , and the processing unit 1 . Figure 3 1 is a block diagram schematically showing an example of the configuration of the control unit 90. The control unit 90 is an electronic circuit and includes, for example, a data processing unit 91 and a storage unit 92. Figure 3In the specific example, the data processing unit 91 and the storage unit 92 are connected to each other via a bus 93. The data processing unit 91 may also be, for example, an arithmetic processing device such as a CPU (Central Processor Unit). The storage unit 92 may also have a non-temporary storage unit (such as a ROM (Read Only Memory) or a hard disk) 921 and a temporary storage unit (such as a RAM (Random Access Memory)) 922. The non-temporary storage unit 921 may also store, for example, a program that specifies the processing to be performed by the control unit 90. The program is executed by the data processing unit 91, and the control unit 90 can execute the processing specified in the program. Of course, part or all of the processing performed by the control unit 90 may also be performed by hardware such as a dedicated logic circuit.

[0052] <Processing Department>

[0053] Figure 4 1 is a diagram schematically showing an example of the configuration of the processing unit 1 according to the first embodiment. Figure 4 As long as at least one processing unit 1 of the substrate processing apparatus 100 has Figure 4 The configuration shown as an example may be sufficient.

[0054] The processing unit 1 performs organic matter removal processing on the substrate W by supplying a mixed solution of sulfuric acid and hydrogen peroxide solution (hereinafter referred to as SPM solution) to the main surface of the substrate W. Here, a resist layer R as an example of an organic layer is formed on the main surface of the substrate W. Figure 4 As shown, the processing unit 1 includes a substrate holding unit 2 and a first nozzle 3 .

[0055] At Figure 4 In the example, the processing unit 1 also includes a chamber 10. The chamber 10 has a box shape. The internal space of the chamber 10 corresponds to the processing space for processing the substrate W. The chamber 10 is provided with an openable and closable carry-in and carry-out port (not shown). The central robot 122 carries the unprocessed substrate W into the chamber 10 through the carry-in and carry-out port, and also carries the processed substrate W out of the chamber 10 through the carry-in and carry-out port. The substrate W is carried into the chamber 10, for example, with the main surface having the resist layer R facing vertically upward. That is, here, the main surface of the substrate W on which the resist layer R is formed becomes the upper surface.

[0056] The substrate holding unit 2 is arranged in the chamber 10. The substrate W is delivered to the substrate holding unit 2 from the center robot 122. The substrate holding unit 2 holds the substrate W in a horizontal posture and rotates the substrate W around the rotation axis Q1. The horizontal posture mentioned here refers to a posture in which the thickness direction of the substrate W is along the vertical direction. The rotation axis Q1 is an axis passing through the center of the substrate W and along the vertical direction. This substrate holding unit 2 can also be called a rotary chuck. Here, the substrate holding unit 2 holds the substrate W in a posture in which the main surface having the anti-etching layer R faces vertically upward.

[0057] At Figure 4 In the example shown in FIG. 1 , the substrate holding unit 2 includes a rotation base 21, a plurality of chuck pins 22, and a rotation drive unit 23. The rotation base 21 has a plate shape (eg, a circular plate shape) and is disposed with its thickness direction extending along the vertical direction.

[0058] A plurality of chuck pins 22 are provided on the upper surface of the rotating base 21. The plurality of chuck pins 22 are provided, for example, at equal intervals along the circumferential direction about the rotation axis Q1. The plurality of chuck pins 22 are configured to be able to move between a holding position and a release position to be described below. The so-called holding position refers to the position where the chuck pins 22 abut against the periphery of the substrate W. The substrate W is held by the plurality of chuck pins 22 by stopping at each holding position. Figure 4 , the chuck pins 22 are shown stopped at the holding position. The release position refers to the position where each chuck pin 22 is clear of the substrate W. By stopping the chuck pins 22 at each release position, the chuck pins 22 release their hold on the substrate W. The substrate holding unit 2 also includes a pin drive unit (not shown) that moves the chuck pins 22. The pin drive unit includes a drive source such as a motor or an air cylinder and is controlled by the control unit 90.

[0059] The rotation drive unit 23 includes a shaft 231 and a motor 232. The upper end of the shaft 231 is connected to the lower surface of the spin base 21, and the shaft 231 extends from the lower surface of the spin base 21 along the rotation axis Q1. The motor 232 is controlled by the control unit 90 to rotate the shaft 231 about the rotation axis Q1. As a result, the spin base 21, the chuck pins 22, and the substrate W rotate integrally about the rotation axis Q1.

[0060] Furthermore, the substrate holding portion 2 does not necessarily have to include the chuck pins 22. For example, the substrate holding portion 2 may hold the substrate W using a chuck system such as a vacuum chuck, an electrostatic chuck, or a Bernoulli chuck.

[0061] The first nozzle 3 is provided in the chamber 10 vertically above the substrate W held by the substrate holding portion 2. The first nozzle 3 ejects the processing liquid toward the main surface of the substrate W held by the substrate holding portion 2. Figure 4In the example of FIG. 5 , the first nozzle 3 can eject an SPM liquid obtained by mixing sulfuric acid and hydrogen peroxide solution as the processing liquid.

[0062] The processing unit 1 can eject the SPM liquid from the first nozzle 3 at a variable concentration. Figure 4 In the example, the first nozzle 3 is connected to the downstream end of the liquid supply pipe 31, and the upstream end of the liquid supply pipe 31 is connected to the mixing section 4. The mixing section 4 is also connected to the first liquid supply pipe 41a and the second liquid supply pipe 41b. Sulfuric acid flows into the mixing section 4 through the first liquid supply pipe 41a, and the carbon dioxide aqueous solution flows into the mixing section 4 through the second liquid supply pipe 41b. Therefore, sulfuric acid and hydrogen peroxide solution are mixed in the mixing section 4. The mixing section 4 supplies the SPM liquid formed by the mixture of sulfuric acid and hydrogen peroxide solution to the liquid supply pipe 31. Figure 4 In the example shown in FIG. 4 , the liquid supply pipe 31 , the first liquid supply pipe 41 a , and the second liquid supply pipe 41 b are connected to each other, and the connection portion functions as the mixing portion 4 .

[0063] A first supply valve 42a and a first flow control valve 43a are inserted into the first liquid supply pipe 41a. Furthermore, the upstream end of the first liquid supply pipe 41a is connected to a sulfuric acid supply source 45a. By opening the first supply valve 42a, sulfuric acid from the sulfuric acid supply source 45a is supplied to the liquid supply pipe 31 through the first liquid supply pipe 41a. The first flow control valve 43a adjusts a first flow rate of sulfuric acid flowing through the first liquid supply pipe 41a. The first supply valve 42a and the first flow control valve 43a are controlled by the control unit 90. Figure 4 In the example shown in FIG. 1 , a first flow sensor 44a is also provided in the first liquid supply pipe 41a. The first flow sensor 44a measures a first flow rate of sulfuric acid flowing through the first liquid supply pipe 41a. The first flow control valve 43a adjusts the first flow rate of sulfuric acid flowing through the first liquid supply pipe 41a based on the measurement result of the first flow sensor 44a. The combination of the first flow control valve 43a and the first flow sensor 44a may also be a mass flow controller.

[0064] A second supply valve 42b and a second flow control valve 43b are inserted into the second liquid supply pipe 41b. Furthermore, the upstream end of the second liquid supply pipe 41b is connected to a hydrogen peroxide solution supply source 45b. By opening the second supply valve 42b, hydrogen peroxide solution from the hydrogen peroxide solution supply source 45b is supplied to the liquid supply pipe 31 through the second liquid supply pipe 41b. The second flow control valve 43b adjusts the second flow rate of the hydrogen peroxide solution flowing through the second liquid supply pipe 41b. The second supply valve 42b and the second flow control valve 43b are controlled by the control unit 90. Figure 4In the example shown in FIG. 4 , a second flow sensor 44b is also provided in the second liquid supply pipe 41b. The second flow sensor 44b measures the second flow rate of the hydrogen peroxide solution flowing through the second liquid supply pipe 41b. The second flow control valve 43b adjusts the second flow rate of the hydrogen peroxide solution flowing through the second liquid supply pipe 41b based on the measurement result of the second flow sensor 44b. The combination of the second flow control valve 43b and the second flow sensor 44b may also be a mass flow controller.

[0065] According to this configuration, the SPM liquid mixed at a mixing ratio corresponding to the first flow rate of sulfuric acid and the second flow rate of hydrogen peroxide solution flows through the liquid supply pipe 31. The SPM liquid is supplied to the first nozzle 3 through the liquid supply pipe 31 and ejected from the first nozzle 3.

[0066] A heater (not shown) may be provided in the first liquid supply pipe 41a. The heater heats the sulfuric acid flowing through the first liquid supply pipe 41a, raising the temperature of the sulfuric acid to a temperature suitable for treatment. For example, the heater may adjust the temperature of the sulfuric acid to a range higher than room temperature but below 170 degrees Celsius. The heater is controlled by the control unit 90. The heater may be, for example, a resistive heater having a heating wire.

[0067] At Figure 4 In the example of , the first nozzle 3 is a spray nozzle. The first nozzle 3 is, for example, a two-fluid nozzle. The first nozzle 3 can be an internal mixing type spray nozzle or an external mixing type spray nozzle.

[0068] Furthermore, the type of first nozzle 3 is not particularly limited. For example, the first nozzle 3 may be a linear nozzle that ejects the SPM liquid from a single nozzle in a continuous stream. Alternatively, the first nozzle 3 may be a shower nozzle that ejects the SPM liquid from multiple nozzles in a continuous stream. Alternatively, the first nozzle 3 may be a vapor nozzle that ejects vapor of the SPM liquid. In this case, the sulfuric acid supply source 45a supplies sulfuric acid vapor to the first liquid supply pipe 41a, and the hydrogen peroxide solution supply source 45b supplies hydrogen peroxide solution vapor to the second liquid supply pipe 41b. Here, as an example, the first nozzle 3 is a spray nozzle.

[0069] At Figure 4In the example, the downstream end of the gas supply pipe 51 is also connected to the first nozzle 3, and the upstream end of the gas supply pipe 51 is connected to the gas supply source 55. A gas valve 52 and a flow adjustment valve 53 are inserted in the gas supply pipe 51. By opening the gas valve 52, high-pressure inert gas from the gas supply source 55 is supplied to the first nozzle 3 through the gas supply pipe 51. The inert gas supplied to the first nozzle 3 is mixed with the SPM liquid, so that the state of the SPM liquid changes to a droplet state. Therefore, the first nozzle 3 sprays SPM liquid in a droplet state. On the other hand, by closing the gas valve 52, the supply of inert gas to the first nozzle 3 is stopped. The flow adjustment valve 53 adjusts the flow rate of the inert gas flowing in the gas supply pipe 51. The gas valve 52 and the flow adjustment valve 53 are controlled by the control unit 90. Figure 4 In the example shown in FIG. 5 , a flow sensor 54 is also provided in the gas supply pipe 51. The flow sensor 54 measures the flow rate of the inert gas flowing through the gas supply pipe 51. The flow control valve 53 adjusts the flow rate of the hydrogen peroxide solution flowing through the gas supply pipe 51 based on the measurement result of the flow sensor 54. The flow control valve 53 and the flow sensor 54 may be a mass flow controller. The inert gas includes, for example, at least one of nitrogen and a rare gas (e.g., argon).

[0070] At Figure 4 In the example, the processing unit 1 also includes a nozzle moving drive unit 34. The nozzle moving drive unit 34 is controlled by the control unit 90 to move the first nozzle 3 in the chamber 10. Specifically, the nozzle moving drive unit 34 moves the first nozzle 3 between a first processing position and a first standby position to be described below. The first processing position is a position where the first nozzle 3 sprays the SPM liquid toward the main surface of the substrate W held by the substrate holding unit 2, and is a position opposite to the main surface of the substrate W in the vertical direction. Figure 4 The example of FIG. 1 shows the first nozzle 3 stopped at the first processing position. The first standby position is a position where the first nozzle 3 does not eject the SPM liquid toward the main surface of the substrate W held by the substrate holder 2, for example, a position radially outward of the substrate W.

[0071] At Figure 4In the example, the nozzle movement drive unit 34 includes an arm 35, a support column 36, and a rotation drive unit 37. The support column 36 has a columnar shape extending in the vertical direction and is arranged radially outward of the baffle 71 described below when viewed from above. The arm 35 has a rod-like shape extending in the horizontal direction, its base end is connected to the support column 36, and its front end is connected to the first nozzle 3. The rotation drive unit 37 includes a motor (not shown) controlled by the control unit 90, which rotates the support column 36 in the forward and reverse directions around its central axis Q2 within a specific angular range. Therefore, the first nozzle 3 moves back and forth in a circumferential direction about the central axis Q2. The support column 36 is arranged in such a way that the first processing position and the first standby position are located on the movement trajectory of the first nozzle 3. Furthermore, the nozzle movement drive unit 34 does not necessarily have the above-mentioned structure, and may also include a linear motion drive unit such as a ball screw mechanism or a linear motor.

[0072] When the first nozzle 3 is located at the first processing position, the first nozzle 3 ejects the SPM liquid toward the main surface of the rotating substrate W. This supplies the SPM liquid to the main surface of the substrate W. The SPM liquid that lands on the main surface of the substrate W flows radially outward as the substrate W rotates, dispersing outward from the periphery of the substrate W. At this point, the sulfuric acid and hydrogen peroxide solution in the SPM liquid react to produce an active component with high oxidizing power (e.g., persulfuric acid). The SPM liquid removes the resist layer R primarily through the reaction of the active component with the resist layer R.

[0073] At Figure 4 In the example shown in FIG. 1 , the processing unit 1 also includes a second nozzle 6. The second nozzle 6 is disposed within the chamber 10 vertically above the substrate W held by the substrate holder 2. The second nozzle 6 ejects the rinsing liquid toward the main surface of the substrate W held by the substrate holder 2. The type of the second nozzle 6 is not particularly limited, but the second nozzle 6 may be a linear nozzle having a single ejection port that ejects the rinsing liquid in a continuous stream.

[0074] The second nozzle 6 is connected to the downstream end of the liquid supply pipe 61, and the upstream end of the liquid supply pipe 61 is connected to the rinsing liquid supply source 65. The rinsing liquid is, for example, pure water (i.e., deionized water). A supply valve 62 and a flow regulating valve 63 are inserted into the liquid supply pipe 61. By opening the supply valve 62, the rinsing liquid is sprayed from the second nozzle 6, and by closing the supply valve 62, the rinsing liquid is stopped from being sprayed from the second nozzle 6. The flow regulating valve 63 adjusts the flow rate of the rinsing liquid circulating in the liquid supply pipe 61. The flow regulating valve 63 can also be a mass flow controller. The supply valve 62 and the flow regulating valve 63 are controlled by the control unit 90.

[0075] At Figure 4In the example, the processing unit 1 also includes a nozzle moving drive unit 64. The nozzle moving drive unit 64 is controlled by the control unit 90, and moves the second nozzle 6 between a second processing position and a second standby position to be described below. The second processing position is a position where the second nozzle 6 sprays a rinse liquid toward the main surface of the substrate W held by the substrate holding unit 2, for example, a position vertically opposite to the center of the main surface of the substrate W. The second standby position is a position where the second nozzle 6 does not spray a rinse liquid toward the main surface of the substrate W held by the substrate holding unit 2, for example, a position radially outward of the substrate W. Figure 4 , the second nozzle 6 is shown stopped at the second standby position. An example of a specific configuration of the nozzle movement drive unit 64 is the same as that of the nozzle movement drive unit 34.

[0076] When the second nozzle 6 is located at the second processing position, the second nozzle 6 ejects the rinsing liquid toward the main surface of the rotating substrate W. The rinsing liquid lands on the main surface of the substrate W. The rinsing liquid lands on the main surface of the substrate W and flows radially outward as the substrate W rotates, scattering outward from the periphery of the substrate W. Since the rinsing liquid can radially flush the SPM liquid on the main surface of the substrate W outward, the SPM liquid on the main surface of the substrate W can be replaced with the rinsing liquid.

[0077] At Figure 4 In the example of FIG, the processing unit 1 also includes a baffle 71 and a baffle lifting driving unit 73. Figure 4 In the example, a plurality of (specifically, three) baffles 71 are provided. Each baffle 71 has a cylindrical shape that surrounds the substrate W held by the substrate holding portion 2. The plurality of baffles 71 are arranged concentrically with each other. The baffle lifting drive unit 73 is controlled by the control unit 90, and causes each baffle 71 to be raised and lowered between an upper position and a lower position to be described below. The upper position is a position in which the upper end of the baffle 71 is vertically above the substrate W held by the substrate holding portion 2. The lower position is a position in which the upper end of the baffle 71 is vertically below the upper position, for example, a position vertically below the upper surface of the rotating base 21. The baffle lifting drive unit 73 has, for example, a ball screw mechanism or an air cylinder.

[0078] For example, when all baffles 71 are in the upper position, the processing liquid scattered from the periphery of the substrate W is caught by the inner circumferential surface of the inner baffle 71. When the outer baffles 71 and the middle baffle 71 are in the upper position, and the inner baffle 71 is in the lower position, the processing liquid scattered from the periphery of the substrate W is caught by the inner circumferential surface of the middle baffle 71. When only the outer baffle 71 is in the upper position, the processing liquid scattered from the periphery of the substrate W is caught by the inner circumferential surface of the outer baffle 71.

[0079] At Figure 4In the example of FIG, an annular shield 72 is provided corresponding to each baffle 71. The processing liquid flowing down the inner peripheral surface of each baffle 71 is received by the corresponding shield 72. The processing liquid received by each shield 72 is discharged to the outside of the chamber 10 through the pipe 74.

[0080] The processing unit 1 may also include a heating unit (not shown) for heating the substrate W held by the substrate holding unit 2. The heating unit may be, for example, a resistive heater including a heating wire. The heater may be disposed between the substrate W and the spin base 21. Alternatively, the heating unit may include a nozzle that sprays a high-temperature heat medium (e.g., warm water or a high-temperature inert gas) toward the main surface (e.g., the lower surface) of the substrate W.

[0081] <First example of substrate processing>

[0082] Figure 5 2 is a flowchart showing an example of substrate processing. The control unit 90 causes the substrate processing apparatus 100 to execute the processing from step S1 to step S8 according to a preset processing sequence (program). Figure 6 This is a diagram schematically showing an example of the state of the processing unit 1 in step S3, step S4, and step S5 described below. Figure 7 This is a graph showing an example of temporal changes in the first flow rate of sulfuric acid, the second flow rate of the hydrogen peroxide solution, and the sulfuric acid concentration of the SPM liquid.

[0083] First, the central robot 122 moves a substrate W into the chamber 10 of the processing unit 1. The substrate holder 2 receives the substrate W and holds it (step S1: holding process). Specifically, the substrate holder 2 moves the plurality of chuck pins 22 from respective release positions to holding positions. Thus, the plurality of chuck pins 22 hold the substrate W. The substrate holder 2 continues to hold the substrate W until processing of the substrate W is completed. For example, a resist layer R is formed on the main surface (here, the top surface) of the substrate W.

[0084] Next, the substrate holder 2 begins rotating the substrate W about the rotation axis Q1 (step S2: rotation start step). The substrate holder 2 may also maintain the rotation of the substrate W until processing of the substrate W is completed. After step S1, the shutter lift drive 73 appropriately raises the shutter 71 to the upper position.

[0085] Next, the processing unit 1 supplies the SPM liquid onto the main surface of the substrate W (step S3: first process). Specifically, the processing unit 1 ejects the SPM liquid from the first nozzle 3 toward the main surface of the rotating substrate W. More specifically, first, the nozzle movement drive unit 34 moves the first nozzle 3 to the first processing position. Then, the control unit 90 opens the first supply valve 42a, the second supply valve 42b, and the gas valve 52. When the first supply valve 42a and the second supply valve 42b are opened, sulfuric acid flows from the sulfuric acid supply source 45a through the first supply pipe 41a into the supply pipe 31, and hydrogen peroxide solution flows from the hydrogen peroxide solution supply source 45b through the second supply pipe 41b into the supply pipe 31. As a result, the sulfuric acid and hydrogen peroxide solution mix, and the SPM liquid, as the mixed liquid, is supplied to the first nozzle 3 through the supply pipe 31. Furthermore, by opening the gas valve 52, high-pressure inert gas from the gas supply source 55 is supplied to the first nozzle 3 through the gas supply pipe 51. Therefore, the SPM liquid in a droplet state (for example, the SPM liquid in a spray state) is ejected from the first nozzle 3 toward the main surface of the substrate W (see also Figure 6 (a)).

[0086] The nozzle movement drive unit 34 may also move the first nozzle 3 back and forth in a direction (here, horizontal direction) along the main surface of the substrate W. For example, the nozzle movement drive unit 34 may move the first nozzle 3 back and forth between a central position facing the central portion of the main surface of the substrate W and a peripheral position facing the peripheral portion of the main surface of the substrate W. Figure 6 In the example of (a), the first nozzle 3 at the center is indicated by a solid line, and the first nozzle 3 at the periphery is indicated by an imaginary line.

[0087] The SPM liquid on the main surface of the substrate W is subjected to the centrifugal force associated with the rotation, flowing radially outward and scattering outward from the periphery of the substrate W. The SPM liquid scattering from the periphery of the substrate W is caught by the inner peripheral surface of the baffle 71 and discharged to the outside of the chamber 10 through the shield 72 and the pipe 74. This aspect also applies to the following steps.

[0088] In step S3, the processing unit 1 supplies the SPM liquid mixed at a relatively high reactive mixing ratio (= first flow rate / second flow rate) to the main surface of the substrate W (see also Figure 7). The ratio of the sulfuric acid concentration in the SPM liquid to the hydrogen peroxide concentration is, for example, greater than 1 / 3 and less than 4, more specifically, 2 (i.e., sulfuric acid: hydrogen peroxide solution = 2:1). The control unit 90 controls the first flow adjustment valve 43a and the second flow adjustment valve 43b in such a manner that the ratio is close to a value within this range. Furthermore, the high reactivity mentioned here means that the amount of active ingredient produced per unit time in the SPM liquid is large. That is, in step S3, the processing unit 1 supplies the SPM liquid mixed at a mixing ratio that produces a large amount of active ingredient per unit time to the main surface of the substrate W.

[0089] Figure 8 1 is a diagram showing an example of a partial structure of the substrate W after each of the following steps S3 and S4. Figure 8 As shown in (a), in step S3, the first hardened layer Ra in the resist layer R is primarily removed using the SPM liquid. This is because the SPM liquid readily acts on the first hardened layer Ra on the surface side of the resist layer R. That is, the active ingredients in the SPM liquid primarily react with the first hardened layer Ra. In step S3, since more active ingredients are produced, more of them react with the first hardened layer Ra. Therefore, the processing unit 1 can more appropriately remove the first hardened layer Ra. That is, although the first hardened layer Ra is relatively hard, since more active ingredients react with the first hardened layer Ra, the first hardened layer Ra can be more appropriately removed.

[0090] In step S3, although the SPM liquid can also act on the portion of the second hardened layer Rc that protrudes outward from the non-hardened layer Rb, it is less likely to act on this portion compared to the first hardened layer Ra. The reason is that when the impurities are injected, the impurities and the resist are bonded to the base layer (e.g., silicon layer) of the substrate W, so the second hardened layer Rc is harder than the first hardened layer Ra. Therefore, compared to the first hardened layer Ra, the SPM liquid is less likely to act on the second hardened layer Rc, and the second hardened layer Rc is not easy to be removed. Therefore, in Figure 8 In example (a), the portion of the second hardened layer Rc that protrudes outward from the unhardened layer Rb also remains. Furthermore, because the second hardened layer Rc is located at the bottom of the resist layer R, the SPM liquid easily accumulates, making it difficult for fresh SPM liquid to act on the second hardened layer Rc. This can also contribute to the remaining second hardened layer Rc.

[0091] Furthermore, in the above example, in step S3, the first nozzle 3 ejects the SPM liquid in droplet form. Consequently, the multiple droplets of the SPM liquid collide with the SPM liquid layer on the main surface of the substrate W. Consequently, the collision force (also referred to as a physical force) is also transmitted to the resist layer R. This physical force acts on the first hardened layer Ra of the resist layer R on the main surface of the substrate W, promoting the peeling of the first hardened layer Ra from the main surface of the substrate W. Consequently, the processing unit 1 can more efficiently remove the first hardened layer Ra.

[0092] When the first specific time has passed since the start of step S3, the processing unit 1 ends step S3. The control unit 90 can measure the elapsed time, for example, using a timer circuit (not shown). The first specific time is pre-set to be longer than the time required to remove the first hardened layer Ra, and is stored in the storage unit 921, for example. The greater the thickness of the first hardened layer Ra, the longer the first specific time can be set. Furthermore, in step S3, a portion of the non-hardened layer Rb and a portion of the second hardened layer Rc can also be removed. Conversely, the first specific time can be set to a time at which most of the non-hardened layer Rb and most of the second hardened layer Rc remain. Therefore, at the end time point of step S3, the non-hardened layer Rb and the second hardened layer Rc of the resist R are exposed.

[0093] Next, the processing unit 1 supplies the SPM liquid mixed at a mixing ratio with a reactivity lower than that of the SPM liquid in step S3 to the main surface of the substrate W (step S4: second process). For example, the sulfuric acid concentration of the SPM liquid in step S4 is lower than that of the SPM liquid in step S3 (see also Figure 7 As a specific example, the ratio of the sulfuric acid concentration to the hydrogen peroxide concentration in the SPM solution is greater than 1 / 4 and less than 1 / 3. In other words, the control unit 90 controls the first flow control valve 43a and the second flow control valve 43b so that the ratio approaches a value within this range. As a specific example, the control unit 90 may also reduce the first flow rate of the sulfuric acid and increase the second flow rate of the hydrogen peroxide solution. Thus, the sulfuric acid concentration in the SPM solution can be reduced.

[0094] In addition, as an example, in step S4, the control unit 90 closes the gas valve 52. By closing the gas valve 52, the first nozzle 3 ejects the SPM liquid in a continuous flow state. The nozzle movement drive unit 34 can move the first nozzle 3 back and forth between the central position and the peripheral position, or stop it at the central position. In the latter case, the SPM liquid ejected from the first nozzle 3 lands on the central portion of the main surface of the rotating substrate W, and is subjected to the centrifugal force accompanying the rotation of the substrate W and flows radially outward on the main surface of the substrate W (see also Figure 6 (b)). Therefore, the SPM liquid is supplied to the entire main surface of the substrate W.

[0095] like Figure 8 As shown in (b), in step S4, the non-hardened layer Rb in the main resist layer R is removed by the SPM liquid. The reason for this is as follows. That is, the SPM liquid will come into contact with the non-hardened layer Rb and the second hardened layer Rc in the resist layer R. In step S4, the amount of effective components produced per unit time in the SPM liquid is small, so the second hardened layer Rc is not easily removed, and the non-hardened layer Rb is mainly removed. In addition, since a portion of the second hardened layer Rc is located directly below the non-hardened layer Rb, the SPM liquid has almost no effect on this portion before the non-hardened layer Rb is removed in step S4. Therefore, the portion of the second hardened layer Rc located directly below the non-hardened layer Rb remains.

[0096] Furthermore, in the above example, since the sulfuric acid concentration of the SPM liquid in step S4 is relatively low, the amount of sulfuric acid used (in other words, the amount of waste) can be reduced.

[0097] In the above example, in step S4, the first nozzle 3 ejects the SPM liquid in a continuous stream. In this case, although the physical force of the liquid droplets does not act on the unhardened layer Rb, even this SPM liquid can remove the soft unhardened layer Rb. Furthermore, the amount of inert gas used can be reduced, thereby lowering operating costs.

[0098] If the second specific time has passed since the start of step S4, the processing unit 1 ends step S4. The second specific time is pre-set, for example, stored in the storage unit 921. The second specific time can also be set to, for example, a time longer than the time required to remove the non-hardened layer Rb. Furthermore, at the end time point of step S4, a non-hardened layer Rb may remain on the main surface of the substrate W. The reason is that the non-hardened layer Rb is removed in the following step S5. On the contrary, in step S4, a portion of the non-hardened layer Rb directly below the second hardened layer Rc may also be removed. In short, the second specific time can be set to a time to remove the non-hardened layer Rb and the portion of the second hardened layer Rc, or it can be set to a time to a degree that a portion of the non-hardened layer Rb remains. The greater the thickness of the non-hardened layer Rb, the longer the second specific time can be set.

[0099] Next, the processing unit 1 supplies the SPM liquid, mixed at a higher reactivity than the SPM liquid in step S4, to the main surface of the substrate W (step S5: third process). For example, the sulfuric acid concentration of the SPM liquid in step S5 is higher than that in step S4. The sulfuric acid concentration is, for example, the same as that in step S3. As a specific example, the control unit 90 may increase the first flow rate of the sulfuric acid and decrease the second flow rate of the hydrogen peroxide solution. This increases the sulfuric acid concentration in the SPM liquid.

[0100] In addition, as an example, in step S5, the control unit 90 opens the gas valve 52. In this case, the first nozzle 3 ejects the SPM liquid in the form of droplets. The nozzle movement drive unit 34 moves the first nozzle 3 back and forth between the central position and the peripheral position (see also Figure 6 (c)).

[0101] In step S5, the SPM liquid contacts the second hardened layer Rc in the resist layer R. In step S5, more active ingredients are produced, and therefore react with the second hardened layer Rc. Therefore, the processing unit 1 can more effectively remove the harder second hardened layer Rc. Furthermore, if any unhardened layer Rb remains at the end of step S4, the SPM liquid will also remove the unhardened layer Rb.

[0102] In the above example, the first nozzle 3 ejects the SPM liquid in a droplet state. Therefore, a physical force also acts on the second hardened layer Rc of the resist layer R on the main surface of the substrate W. Therefore, the processing unit 1 can remove the second hardened layer Rc more efficiently.

[0103] If the third specific time has passed since the start of step S5, the processing unit 1 ends step S5. The third specific time is preset to be longer than the time required to remove the second hardened layer Rc and is stored in the storage unit 921. The thicker the second hardened layer Rc, the longer the third specific time can be set.

[0104] Furthermore, a case where the second hardened layer Rc is not completely removed by step S5 and a portion thereof remains as residue of the resist layer R is also conceivable.

[0105] Therefore, Figure 5 In the example of , the processing unit 1 supplies the SPM liquid to the main surface of the substrate W in a continuous flow state (step S6: finishing SPM process). Specifically, the control unit 90 closes the gas valve 52. Therefore, the first nozzle 3 ejects the SPM liquid in a continuous flow state. The nozzle movement drive unit 34 can move the first nozzle 3 back and forth between the central position and the peripheral position, or stop it at the central position. In the latter case, the SPM liquid ejected from the first nozzle 3 lands on the central part of the main surface of the rotating substrate W, and is subjected to the centrifugal force accompanying the rotation of the substrate W and flows radially outward on the main surface of the substrate W. The sulfuric acid concentration of the SPM liquid in step S6 can also be the same as that in step S5, for example.

[0106] Through step S6 , even if a portion of the resist layer R remains on the main surface of the substrate W, the processing unit 1 can remove the remaining layer. That is, the processing unit 1 can suppress the generation of residues of the resist layer R.

[0107] If the fourth specific time has passed since the start of step S6, the processing unit 1 ends step S6. The fourth specific time is preset and stored in the storage unit 921, for example.

[0108] At Figure 5 In the example shown in FIG. 1 , the processing unit 1 then supplies a hydrogen peroxide solution to the main surface of the substrate W (step S7: extrusion process). Specifically, the control unit 90 closes the first supply valve 42a while the second supply valve 42b is open, thereby stopping the supply of the SPM liquid to the first nozzle 3 while continuing to supply the hydrogen peroxide solution to the first nozzle 3. Consequently, the hydrogen peroxide solution extrudes the sulfuric acid remaining in the supply pipe 31 and the internal flow path of the first nozzle 3, causing it to be ejected from the first nozzle 3. This prevents the sulfuric acid from remaining inside the first nozzle 3. Furthermore, the precipitation of sulfuric acid components inside the first nozzle 3 is suppressed.

[0109] After the sulfuric acid in the first nozzle 3 has been fully discharged, the processing unit 1 stops supplying the hydrogen peroxide solution. For example, after a specific fifth predetermined time has elapsed since the start of step S7, the control unit 90 closes the second supply valve 42b. Closing the second supply valve 42b stops the discharge of the hydrogen peroxide solution from the first nozzle 3. The nozzle movement drive unit 34 then moves the first nozzle 3 to the first standby position.

[0110] Next, the processing unit 1 supplies a rinse liquid to the main surface of the substrate W (step S8: rinse process). First, the nozzle movement drive unit 64 moves the second nozzle 6 to the second processing position. Next, the control unit 90 opens the supply valve 62. As a result, the second nozzle 6 sprays the rinse liquid toward the center of the main surface of the rotating substrate W. The rinse liquid lands on the center of the main surface of the substrate W and flows radially outward on the main surface of the substrate W as the substrate W rotates. Therefore, the rinse liquid can flush the hydrogen peroxide solution on the main surface of the substrate W radially outward. As a result, the processing liquid on the main surface of the substrate W is replaced by the rinse liquid from the hydrogen peroxide solution.

[0111] After the hydrogen peroxide solution on the main surface of the substrate W has been fully replaced with the rinse liquid, the processing unit 1 stops supplying the rinse liquid. For example, after the sixth predetermined time has passed since the start of the rinse liquid supply, the control unit 90 closes the supply valve 62. Closing the supply valve 62 stops the discharge of the rinse liquid from the second nozzle 6. The nozzle movement drive unit 64 then moves the second nozzle 6 to the second standby position.

[0112] Next, the processing unit 1 dries the substrate W (step S9: drying process). For example, the substrate holding unit 2 increases the rotation speed of the substrate W (so-called spin drying). As a result, the substrate W is dried.

[0113] When the substrate W is sufficiently dried, the processing unit 1 stops the rotation of the substrate W. For example, the substrate holding unit 2 stops the rotation of the substrate W when a seventh specific time has passed since the increase in the rotation speed.

[0114] Next, the substrate holder 2 releases its grip on the substrate W (step S10: grip release process). Specifically, the substrate holder 2 moves the plurality of chuck pins 22 from their respective gripping positions to their release positions, thereby releasing the grip on the substrate W. Next, the central robot 122 receives the substrate W from the substrate holder 2 and unloads the substrate W from the processing unit 1.

[0115] Effects

[0116] As described above, the processing unit 1 can remove the resist layer R from the main surface of the substrate W. Furthermore, according to the present substrate processing method, in step S3, which primarily targets the relatively hard first hardened layer Ra for removal, the processing unit 1 supplies a highly reactive SPM liquid to the main surface of the substrate W. Consequently, more active ingredients can act on the first hardened layer Ra, enabling more appropriate removal of the first hardened layer Ra.

[0117] In the above example, the first specific time for spraying the SPM liquid in step S3 is pre-set to be longer than the time required to remove the first hardened layer Ra. Therefore, the processing unit 1 can more reliably remove the first hardened layer Ra in step S3. Furthermore, in step S3, a portion of the unhardened layer Rb and a portion of the second hardened layer Rc can also be removed.

[0118] In step S4, which primarily targets the removal of the unhardened layer Rb, the processing unit 1 supplies a less reactive SPM solution to the main surface of the substrate W. Because the unhardened layer Rb is relatively soft, the processing unit 1 can remove it even if the amount of active ingredient produced per unit time is relatively small. Therefore, in step S4, a mixing ratio that reduces the amount of sulfuric acid used can be employed. As a specific example, the sulfuric acid concentration of the SPM solution in step S4 is set lower than that of the SPM solution in step S3. This reduces the amount of sulfuric acid used.

[0119] In the above example, in step S4 , the first nozzle 3 ejects the SPM liquid in a continuous flow toward the main surface of the substrate W. Therefore, the amount of inert gas used can be reduced.

[0120] In step S5 in which the second hardened layer Rc, which is relatively hard, is mainly removed, the processing unit 1 supplies the SPM liquid having a relatively high reactive concentration to the main surface of the substrate W. Therefore, the second hardened layer Rc can be removed more appropriately.

[0121] In the above example, in each of steps S3 and S5, the first nozzle 3 ejects the SPM liquid in droplet form toward the main surface of the substrate W. This allows the physical force of the multiple droplets to act on the resist layer R on the substrate W, thereby promoting the removal of the resist layer R. Furthermore, the first nozzle 3 need not necessarily eject the SPM liquid in droplet form in both steps S3 and S5. Alternatively, the first nozzle 3 may eject the SPM liquid in droplet form in one of steps S3 and S5, while ejecting the SPM liquid in a continuous state in the other step.

[0122] In the above example, the third specific time for spraying the SPM liquid in step S5 is set to be longer than the time required to remove the second hardened layer Rc. Therefore, in step S5, the second hardened layer Rc can be removed more reliably.

[0123] In the above example, step S6 is performed after step S5. Therefore, the processing unit 1 can suppress the generation of residues of the resist layer R.

[0124] <Second embodiment>

[0125] Figure 9 1 is a diagram showing a first example of the configuration of the processing unit 1 according to the second embodiment. Figure 9 In the example shown, a tank 46 of a sulfuric acid supply source 45a is shown. Sulfuric acid is stored in the tank 46. For example, the upstream end of the first liquid supply pipe 41a is connected to the tank 46. The sulfuric acid in the tank 46 is supplied to the main surface of the substrate W through the first liquid supply pipe 41a, the liquid supply pipe 31, and the first nozzle 3.

[0126] Furthermore, sulfuric acid supply source 45a may also include a circulation pipe (not shown) for adjusting the temperature of tank 46. The upstream and downstream ends of the circulation pipe are connected to tank 46, and a heater (not shown) and a pump (not shown) are installed in the circulation pipe. By circulating the sulfuric acid in tank 46 through the circulation pipe and heating the sulfuric acid in the circulation pipe, the temperature of the sulfuric acid in tank 46 can be adjusted to a specific range suitable for treatment.

[0127] At Figure 9 In the example, the downstream portion of the piping 74 connected to the shield 72 corresponding to the inner baffle 71 is connected to the sulfuric acid supply source 45a. The downstream end of the piping 74 functions as a supply port to the tank 46. In the second embodiment, the SPM liquid ejected from the first nozzle 3 to the substrate W flows radially outward on the main surface of the substrate W and scatters from the periphery of the substrate W and is caught by the inner baffle 71. The SPM liquid caught by the inner baffle 71 is recovered to the tank 46 through the shield 72 and the piping 74. That is, in Figure 9In the example, the pipe 74 corresponding to the inner baffle 71 functions as a recovery pipe for returning the SPM liquid to the tank 46. The downstream end of the pipe 74 connected to the other shield 72 can be connected to an external waste unit (factory entity).

[0128] Furthermore, while the piping 74 corresponding to the inner baffle 71 is shown here as functioning as a recovery pipe, this is not necessarily the case. Alternatively, the downstream end of the piping 74 corresponding to the outer or middle baffle 71 can be connected to the tank 46, allowing this piping 74 to function as a recovery pipe. In this case, when the SPM liquid is ejected from the first nozzle 3, the baffle 71 corresponding to the piping 74 functioning as a recovery pipe is in the upper position, catching the SPM liquid. Hereinafter, the piping 74 corresponding to the inner baffle 71 is assumed to function as a recovery pipe.

[0129] An example of substrate processing in the second embodiment Figure 5 However, the specific actions in step S3 (first process), step S4 (second process) and step S5 (third process) may be different. Figure 10 FIG. 1 is a diagram schematically showing an example of the state of the processing unit 1 in steps S3 to S5. Figure 11 This is a sequence diagram showing an example of the operation of the processing unit 1 .

[0130] In the second embodiment, the SPM liquid supplied to the substrate W in step S3 is discarded. As a specific example, in step S3, the baffle lifting drive unit 73 places the outer baffle 71 and the middle baffle 71 in the upper position and places the inner baffle 71 in the lower position (see FIG. Figure 10 and Figure 11 Therefore, in step S3, the SPM liquid scattered from the periphery of the substrate W is caught by the inner circumferential surface of the middle baffle 71 and discharged to an external waste area through the shield 72 and piping 74 corresponding to the middle baffle 71. Furthermore, in step S3, the outer baffles 71 can also catch the SPM liquid. In other words, the baffle lifting drive 73 can also position the upper baffle 71 in the upper position and the middle baffle 71 in the lower position.

[0131] After the first hardened layer Ra is removed in step S3, in other words, after the first specific time has passed, the processing unit 1 supplies the SPM liquid mixed at a mixing ratio with a reactivity lower than that of the SPM liquid in step S3 to the main surface of the substrate W (step S4: second process). However, in the second embodiment, the sulfuric acid concentration of the SPM liquid in step S4 is higher than that of the SPM liquid in step S3 (see Figure 11For example, the ratio of the sulfuric acid concentration to the hydrogen peroxide concentration in the SPM solution is set within a range greater than 4 and less than 20. As a specific example, it is set to approximately 10 (i.e., sulfuric acid:hydrogen peroxide solution = 10:1). The control unit 90 controls the first flow control valve 43a and the second flow control valve 43b so that the ratio approaches a value within this range. As a specific example, the control unit 90 may increase the first flow rate of the sulfuric acid and decrease the second flow rate of the hydrogen peroxide solution. Thus, the sulfuric acid concentration can be increased.

[0132] In the second embodiment, the SPM liquid supplied to the substrate W in step S4 is recovered and reused. As a specific example, in step S4, the baffle lifting drive unit 73 moves the outer baffle 71, the middle baffle 71, and the inner baffle 71 to the upper position (refer to Figure 10 and Figure 11 Therefore, the SPM liquid scattered from the periphery of the substrate W in step S4 is caught by the inner peripheral surface of the inner baffle 71 and is recovered into the tank 46 through the shield 72 corresponding to the inner baffle 71 and the pipe 74 (recovery pipe).

[0133] As described above, in step S4, the SPM liquid having a high sulfuric acid concentration is supplied to the substrate W and then recovered in the tank 46. Since the sulfuric acid concentration of the SPM liquid is relatively high, even when the SPM liquid is recovered in the tank 46, a decrease in the sulfuric acid concentration in the tank 46 is suppressed. Thus, the sulfuric acid in the tank 46 is reused for processing the substrate W.

[0134] After the unhardened layer Rb is removed in step S4, in other words, after the second specific time has passed, the processing unit 1 supplies the SPM liquid mixed with a reactivity higher than that of the SPM liquid in step S4 to the main surface of the substrate W (step S5: third process). However, in the second embodiment, the sulfuric acid concentration of the SPM liquid in step S5 is lower than that of the SPM liquid in step S4 (see Figure 11 The ratio of the sulfuric acid concentration to the hydrogen peroxide concentration in the SPM liquid is the same as that in step S3.

[0135] In the second embodiment, the SPM liquid supplied to the substrate W in step S5 is discarded. As a specific example, in step S5, the baffle lifting drive unit 73 places the outer baffle 71 and the middle baffle 71 in the upper position, and places the inner baffle 71 in the lower position (see Figure 10 and Figure 11 Therefore, the SPM liquid scattered from the periphery of the substrate W in step S5 is caught by the inner peripheral surface of the middle baffle 71 and discharged to the waste part through the shield 72 and the pipe 74 corresponding to the middle baffle 71.

[0136] After the second hardened layer Rc is removed in step S5 , in other words, after the third specific time has passed, the processing unit 1 ends step S5 and sequentially performs steps S6 to S10 , similar to the first embodiment.

[0137] As described above, in the second embodiment, a highly reactive SPM liquid is also supplied to the substrate W in each of steps S3 and S5, while a less reactive SPM liquid is supplied in step S4. Therefore, similar to the first embodiment, the first hardened layer Ra and the second hardened layer Rc can be appropriately removed using the highly reactive SPM liquid, while the unhardened layer Rb can be removed using the less reactive SPM liquid. Furthermore, in the second embodiment, the SPM liquid supplied to the substrate W in step S4 has a high sulfuric acid concentration, and this high sulfuric acid concentration SPM liquid is recovered in the tank 46. Consequently, the amount of sulfuric acid used in step S4 can be further reduced.

[0138] Furthermore, in the above example, the baffle 71 for disposal is provided separately from the baffle 71 for recovery. Specifically, the baffle 71 that receives the SPM liquid with a high sulfuric acid concentration in step S4 is different from the baffle 71 that receives the SPM liquid with a low sulfuric acid concentration in steps S3 and S5. This prevents the SPM liquid with a low sulfuric acid concentration from entering the tank 46.

[0139] <Second example of the processing department>

[0140] Figure 12 1 is a diagram showing a second example of the configuration of the processing unit 1 according to the second embodiment. Figure 12 In the example shown, the downstream end of the pipe 74 corresponding to the inner baffle 71 is connected to a switching unit 75. The upstream ends of a waste pipe 741 and a recovery pipe 742 are also connected to the switching unit 75. The downstream end of the waste pipe 741 is connected to an external waste unit, while the downstream end of the recovery pipe 742 functions as a supply port to the tank 46. The switching unit 75 switches the pipe connected to the pipe 74 between the waste pipe 741 and the recovery pipe 742. The switching unit 75 is, for example, a three-way valve. The switching unit 75 is controlled by the control unit 90.

[0141] When the switching unit 75 connects the piping 74 to the waste pipe 741, the SPM liquid received by the inner baffle 71 passes through the shield 72 corresponding to the inner baffle 71, the piping 74, and the waste pipe 741, and is discharged to the waste portion. When the switching unit 75 connects the piping 74 to the recovery pipe 742, the SPM liquid received by the inner baffle 71 passes through the shield 72 corresponding to the inner baffle 71, the piping 74, and the recovery pipe 742, and is recovered in the tank 46.

[0142] Here, the pipe 74 corresponding to the inner baffle 71 is connected to the switching unit 75, but this is not necessarily the case. The pipe 74 corresponding to the outer baffle 71 or the middle baffle 71 may also be connected to the switching unit 75. Hereinafter, the switching unit 75 is assumed to be connected to the pipe 74 corresponding to the inner baffle 71.

[0143] An example of the operation of the substrate processing apparatus 100 is Figure 5 The same as above. However, in all steps S3 through S5, the baffle lift drive 73 positions the outer baffle 71, the middle baffle 71, and the inner baffle 71 in the upper position. Furthermore, in step S4 (the second step), the processing unit 1 supplies an SPM liquid having a higher sulfuric acid concentration than both steps S3 (the first step) and S5 (the third step) to the main surface of the substrate W.

[0144] Furthermore, in step S4, the switching unit 75 connects the pipe 74 to the recovery pipe 742. Therefore, after the SPM liquid with a relatively high sulfuric acid concentration is supplied to the substrate W in step S4, it passes through the inner baffle 71, the shield 72, the pipe 74, and the recovery pipe 742 and is recovered in the tank 46. On the other hand, in each of steps S3 and S5, the switching unit 75 connects the pipe 74 to the waste pipe 741. Therefore, after the SPM liquid with a relatively low sulfuric acid concentration is supplied to the substrate W, it passes through the inner baffle 71, the shield 72, the pipe 74, and the waste pipe 741 and is discharged to the waste.

[0145] As described above, in the second example of the processing unit 1, the SPM liquid supplied to the substrate W in step S4 has a high sulfuric acid concentration, and the SPM liquid with a high sulfuric acid concentration is recovered in the tank 46. Therefore, the amount of sulfuric acid used in step S4 can be further reduced.

[0146] While the substrate processing method has been described in detail above, all aspects of the description are illustrative and the disclosure is not limited thereto. Furthermore, the various variations described above may be combined and applied as long as they do not conflict with each other. Furthermore, it should be understood that numerous variations not illustrated are contemplated without departing from the scope of the disclosure.

[0147] In the above example, the processing unit 1 performs step S6 (the finishing process SPM), but step S6 can be omitted. If the processing unit 1 does not perform step S6, the processing unit 1 can perform step S7 (the extrusion process) after step S5 (the third process). In step S7, since the hydrogen peroxide solution is sprayed from the first nozzle 3, the possibility of sulfuric acid remaining inside the first nozzle 3 is reduced.

[0148] In addition, in the above example, the substrate processing apparatus 100 is a single-wafer processing apparatus, but it may also be a batch processing apparatus. For example, the substrate processing apparatus 100 may also include a first processing tank storing an SPM liquid mixed at a higher reactivity ratio, and a second processing tank storing an SPM liquid mixed at a lower reactivity ratio. The substrate processing apparatus 100 may also immerse a plurality of substrates W in the SPM liquid in the first processing tank to remove the first hardened layer Ra, then immerse the plurality of substrates W in the SPM liquid in the second processing tank to remove the unhardened layer Rb, and then immerse the plurality of substrates W again in the SPM liquid in the first processing tank to remove the second hardened layer Rc. Furthermore, the first processing tank does not necessarily store the SPM liquid; a spray nozzle may be provided in the first processing tank. The substrate processing apparatus 100 may also load the plurality of substrates W into the first processing tank and spray the SPM liquid in a droplet state toward the plurality of substrates W from the spray nozzle.

[0149] Description of Reference Numerals

[0150] 31: Liquid supply pipe

[0151] 452: Recycling pipe

[0152] 46: Can

[0153] 74: Recovery pipe (piping)

[0154] R: organic layer (resist layer)

[0155] Ra: first hardened layer

[0156] Rb: non-hardened layer

[0157] Rc: Second hardened layer

[0158] S1: Maintaining process (step)

[0159] S3: First process (step)

[0160] S4: Second process (step)

[0161] S5: The third process (step)

[0162] W: substrate

Claims

1. A substrate processing method for removing an organic layer from a substrate, wherein the organic layer having a first hardened layer, a non-hardened layer, and a second hardened layer is formed on a main surface of the substrate, the substrate processing method comprising: a holding step of holding the substrate; In a first step, a mixed solution of sulfuric acid and hydrogen peroxide solution is supplied to the main surface of the substrate to remove the first hardened layer; a second step of supplying the mixed liquid, which is mixed at a mixing ratio lower in reactivity than the mixed liquid in the first step, to the main surface of the substrate after the first step, to remove the uncured layer; as well as In a third step, after the second step, the mixed liquid mixed at a mixing ratio having a higher reactivity than the mixed liquid in the second step is supplied to the main surface of the substrate to remove the second hardened layer.

2. The substrate processing method according to claim 1, wherein: In at least any one of the first step and the third step, the mixed liquid is supplied to the main surface of the substrate in a droplet state. In the second step, the mixed liquid is supplied to the main surface of the substrate in a continuous flow state.

3. The substrate processing method according to claim 2, wherein: After the third step, a finishing step SPM is further provided in which the mixed liquid is supplied to the main surface of the substrate in a continuous flow state. In the third step, the mixed liquid is supplied to the main surface of the substrate in a droplet state.

4. The substrate processing method according to any one of claims 1 to 3, wherein: The sulfuric acid concentration of the mixed liquid in the second step is lower than the sulfuric acid concentration of the mixed liquid in the first step.

5. The substrate processing method according to any one of claims 1 to 3, wherein: The sulfuric acid concentration of the mixed liquid in the second step is higher than the sulfuric acid concentration of the mixed liquid in the first step, In the second step, sulfuric acid stored in a tank is supplied to the main surface of the substrate through a liquid supply pipe, and the mixed liquid that has passed through the main surface of the substrate is returned to the tank through a recovery pipe.

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