JP2023096789A - Substrate processing method and substrate processing device - Google Patents

Abstract

To provide a technique capable of suppressing generation of particles when peeling a resist using a method of irradiating a liquid membrane with plasma.SOLUTION: A substrate processing method includes: a liquid membrane forming step (step S1) of supplying acidic process liquid to a substrate, in which a resist is provided, thereby forming a liquid membrane of the process liquid; a plasma processing step of progressing peeling processing of the resist by irradiating the substrate holding the liquid membrane with plasma; and a rinse step (step S7) of performing liquid contact of such rinse liquid (first rinse liquid) as settling a change width of solubility of the resist dissolved in the liquid membrane within an allowable range, in which the resist is not deposited, to the substrate after the peeling processing is finished.SELECTED DRAWING: Figure 5

Description

The present application relates to a substrate processing method and a substrate processing apparatus.

2. Description of the Related Art In a manufacturing process of a semiconductor device, a resist is sometimes provided as a mask in order to selectively perform etching, ion implantation, or the like on the main surface of a substrate. After etching and ion implantation are performed, the resist is no longer needed, so a process of stripping (removing) the resist is performed.

Various methods have been proposed for stripping the resist provided on the substrate. For example, in Patent Document 1, a mixture of sulfuric acid and hydrogen peroxide (SPM liquid) is supplied to a substrate, and the sulfuric acid reacts with the hydrogen peroxide to produce Caro's acid (peroxomonosulfuric acid: H ₂ SO ₅ ) is disclosed as a method of stripping a resist provided on a substrate.

In this method, it is necessary to continue to supply new SPM liquid to the substrate in order to progress the peeling of the resist. Specifically, for example, as described in Patent Document 1, by rotating the substrate, the old SPM liquid used for stripping the resist is shaken off from the substrate, and new SPM liquid is successively applied onto the substrate. By continuing to supply the resist, the peeling of the resist progresses. For this reason, it was difficult to reduce the amount of sulfuric acid used in the method of stripping the resist using the SPM solution.

JP 2019-176125 A

In recent years, when awareness of the environment has increased, there is a strong demand to reduce the amount of sulfuric acid used, which is a chemical with a large environmental load. Therefore, as an alternative method to the method using the SPM liquid, a method of forming a liquid film of an acid processing liquid such as sulfuric acid on the substrate and irradiating the liquid film with plasma has been considered. In this method, active species in the plasma, Caro's acid generated by the reaction of the active species with the liquid film, and the like oxidize the resist, thereby stripping the resist. In this method, it is not necessary to continuously supply fresh sulfuric acid to the substrate in order to advance the stripping of the resist. Therefore, compared to the method using the SPM liquid, it is possible to reduce the amount of processing liquid such as sulfuric acid used.

However, it has been found that although the above method has the advantage of being able to reduce the amount of processing liquid used, it also has the problem that particles tend to be generated on the substrate after processing.

The reason is considered as follows. That is, in the above method, after a liquid film of, for example, sulfuric acid is formed on the substrate, while the liquid film is maintained on the substrate in a puddle state, the substrate is irradiated with plasma to strip the resist. progresses. Therefore, the stripped resist is dissolved one after another into the liquid film held on the substrate. Therefore, at the stage when the resist stripping process is completed by the plasma irradiation for a predetermined time, almost the entire amount of the stripped resist is dissolved in the liquid film on the substrate.

After the resist stripping process is finished, a process of washing away the liquid film on the substrate with a rinsing liquid is performed. At this time, for example, when pure water as a rinsing liquid is supplied to the liquid film of sulfuric acid, the pH value of the liquid film rises sharply, and the liquid film in which the resist is dissolved (that is, the resist solution (liquid film as As a result, the resist that cannot be completely dissolved precipitates (re-precipitates) (so-called pH shock). It is considered that particles are generated by the deposited resist adhering to the substrate.

Such a phenomenon is less likely to occur when the resist is stripped using the SPM liquid. That is, when the SPM liquid is used, as described above, while the old SPM liquid is being shaken off from the substrate, new SPM liquid is continuously supplied onto the substrate, thereby advancing the peeling of the resist. Therefore, the stripped resist is successively shaken off together with the old SPM solution and discharged from the substrate. At the end of the stripping process, the SPM solution shaken off from the substrate contains contamination such as the stripped resist. Contains almost no material. Therefore, it is considered that almost no resist remains on the substrate when the stripping process is completed. Therefore, even if, for example, pure water is supplied to the substrate as a rinsing liquid after the stripping process is completed, the possibility of depositing the resist is low. Therefore, the phenomenon that the deposited resist adheres to the substrate is less likely to occur.

In this way, when the resist is stripped using the method of irradiating the liquid film with plasma, the problem that does not occur with the method using the SPM liquid, that is, the problem that particles tend to be generated on the substrate after processing, is solved. need to be resolved.

The present application has been made in view of such problems, and its purpose is to provide a technique capable of suppressing the generation of particles when removing a resist using a method of irradiating a liquid film with plasma. be.

A first aspect is a substrate processing method, comprising: a liquid film forming step of supplying an acidic processing liquid to a substrate provided with a resist to form a liquid film of the processing liquid; a plasma treatment step of irradiating the substrate with plasma to progress the resist stripping process, and a change width of the solubility of the resist dissolved in the liquid film on the substrate after the stripping process and a rinsing step of contacting the resist with a rinsing liquid within an allowable range in which the resist is not precipitated.

A second aspect is the substrate processing method according to the first aspect, wherein the rinse liquid is an acidic liquid whose pH value difference with the liquid film is equal to or less than the maximum allowable pH difference. Then, the variation width of the solubility is kept within the allowable range.

A third aspect is the substrate processing method according to the second aspect, wherein the rinse liquid has a pH value difference of 2 or less with respect to the liquid film.

A fourth aspect is the substrate processing method according to the second or third aspect, wherein both the rinsing liquid and the processing liquid are sulfuric acid.

A fifth aspect is the substrate processing method according to the fourth aspect, wherein the rinsing liquid and the processing liquid are sulfuric acid having the same concentration.

A sixth aspect is the substrate processing method according to any one of the second to fifth aspects, wherein the rinse liquid is heated and brought into contact with the substrate.

A seventh aspect is the substrate processing method according to the first aspect, wherein the rinsing liquid is such that the temperature difference between the liquid film and the liquid film is equal to or less than the maximum allowable temperature difference. , the variation width of the solubility is kept within the allowable range.

An eighth aspect is the substrate processing method according to the seventh aspect, wherein the rinse liquid is carbonated water heated to a temperature of 80° C. or higher and 100° C. or lower.

A ninth aspect is the substrate processing method according to any one of the first to eighth aspects, wherein in the rinsing step, the substrate is rotated at is rotated step by step.

A tenth aspect is the substrate processing method according to any one of the first to eighth aspects, wherein in the rinsing step, the substrate is immersed in a reservoir containing the rinse liquid.

An eleventh aspect is a substrate processing apparatus comprising: a holding portion for holding a substrate; a liquid supply portion for supplying liquid to the substrate held by the holding portion; and applying plasma to the substrate held by the holding portion. a plasma irradiation unit that irradiates; and a control unit that controls the holding unit, the liquid supply unit, and the plasma irradiation unit. The liquid supply unit supplies an acidic processing liquid to the substrate to form a liquid film of the processing liquid, and the plasma irradiation unit applies plasma to the substrate holding the liquid film. is irradiated to advance the stripping process of the resist, and the liquid supply unit supplies the change width of the solubility of the resist dissolved in the liquid film to the substrate after the stripping process is completed. Supply a rinse solution that is within the allowable range.

According to the substrate processing method according to the first aspect, the rinse liquid is brought into contact with the substrate after the resist stripping process is completed, so that the liquid film in which the stripped resist is dissolved is removed from the substrate. washed away. Here, the rinsing liquid is such that the range of change in solubility of the resist dissolved in the liquid film is within an allowable range in which the resist is not precipitated. In other words, even if the rinse liquid is brought into contact with the liquid, the solubility changes only within an allowable range in which the resist is not precipitated. Therefore, deposition of the resist is not induced by contact with the rinsing liquid. Therefore, generation of particles on the substrate after processing is suppressed.

According to the substrate processing method according to the second aspect, since the pH value is used as an index to select the rinse liquid, the range of change in solubility when the rinse liquid contacts the liquid can be kept within an allowable range. A rinse liquid can be selected simply and appropriately.

According to the substrate processing method according to the third aspect, it is possible to sufficiently reduce the width of change in solubility when the rinse liquid is brought into contact with the substrate, and to sufficiently suppress the generation of particles.

According to the substrate processing method according to the fourth aspect, since both the rinsing liquid and the processing liquid are sulfuric acid, compared to the case where different types of liquids are used for each, the piping system required for supplying the liquids is reduced. is simplified.

According to the substrate processing method according to the fifth aspect, since the rinsing liquid and the processing liquid are sulfuric acid having the same concentration, the pH value hardly changes when the rinsing liquid comes into contact with the liquid film. do not have. Therefore, it is possible to make the width of change in solubility particularly small when the rinsing liquid comes into contact with the liquid, and it is possible to sufficiently suppress the generation of particles.

According to the substrate processing method according to the sixth aspect, the rinse liquid is heated and then brought into contact with the substrate. The width of temperature change can be kept sufficiently small. In other words, both the width of change in pH and the width of change in temperature can be kept small. Therefore, the range of change in solubility when the rinse liquid is brought into contact with the liquid can be made particularly small, and the generation of particles can be particularly sufficiently suppressed.

According to the substrate processing method according to the seventh aspect, it is possible to use various liquids as the rinsing liquid by adjusting the temperature.

According to the substrate processing method according to the eighth aspect, carbonated water heated to a temperature of 80° C. or higher and 100° C. or lower is used as the rinsing liquid. With such a rinsing liquid, even if the rinsing liquid comes into contact with the liquid film heated by being irradiated with plasma, the width of the temperature change can be kept sufficiently small. Therefore, it is possible to sufficiently reduce the width of change in solubility when the rinse liquid is brought into contact with the liquid, thereby sufficiently suppressing the generation of particles.

According to the substrate processing method of the ninth aspect, in the rinsing step, the substrate is rotated while the number of revolutions is increased stepwise while the rinse liquid is discharged from the nozzle toward the substrate. If the rotational speed is increased all at once instead of stepwise, the speed at which the liquid is supplied onto the substrate cannot catch up with the speed at which the liquid is discharged from the substrate, and a gas-liquid interface appears on the substrate, causing the liquid to There is a risk that an exposed portion may be generated without being covered by the coating. Particles and the like tend to adhere to such portions, and the cleanliness of the substrate tends to decrease. According to the above configuration in which the number of revolutions is increased stepwise, such a gas-liquid interface is less likely to appear on the substrate, so that the cleanliness of the substrate is less likely to deteriorate. That is, the liquid film in which the stripped resist is dissolved can be replaced with the rinsing liquid without lowering the cleanliness of the substrate.

According to the substrate processing method according to the tenth aspect, in the rinsing step, the substrate is immersed in the reservoir containing the rinsing liquid, so that the liquid film in which the peeled resist is dissolved is rapidly discharged from the substrate. , can be replaced with a rinse solution.

According to the substrate processing apparatus according to the eleventh aspect, the rinse liquid is supplied to the substrate after the resist stripping process is completed, and the rinse liquid is brought into contact with the substrate, thereby dissolving the stripped resist. The liquid film is washed off the substrate. Here, the rinsing liquid is such that the range of change in solubility of the resist dissolved in the liquid film is within an allowable range in which the resist is not precipitated. In other words, even if the rinse liquid is brought into contact with the liquid, the solubility changes only within an allowable range in which the resist is not precipitated. Therefore, deposition of the resist is not induced by contact with the rinsing liquid. Therefore, generation of particles on the substrate after processing is suppressed.

It is a top view which shows the structure of a substrate processing system typically. 3 is a block diagram showing the configuration of a control unit; FIG. It is a side view which shows typically the structure of the processing unit which concerns on 1st Embodiment. 1A and 1B are a side sectional view and a plan view schematically showing the configuration of a plasma reactor; FIG. It is a figure which shows the flow of the process performed in a processing unit. It is a figure for demonstrating a holding process. It is a figure for demonstrating a liquid film formation process. It is a figure for demonstrating plasma processing. It is a figure for demonstrating a 1st rinse process. It is a figure for demonstrating a 2nd rinse process. It is a figure which shows typically the relationship between the maximum allowable pH difference and the difference of temperature. It is a figure for demonstrating the flow of the process which concerns on a rinse process. 4 is a micrograph showing a state of a substrate after processing when sulfuric acid, which is the same as the processing liquid, is used as the first rinsing liquid. It is a figure which shows typically the relationship between the maximum allowable temperature difference and the difference of a pH value. FIG. 7 is a side view schematically showing the configuration of a processing unit according to the second embodiment; FIG. 11 is a side view schematically showing the configuration of an immersion unit according to a third embodiment; It is a figure which shows the flow of the process which concerns on a rinse process. 4 is a micrograph showing a state of a substrate after processing when sulfuric acid, which is the same as the processing liquid, is used as a rinsing liquid. It is a side view which shows typically the structure of the processing unit which concerns on a modification. 4 is a micrograph showing a state of a substrate after processing when pure water is used as a rinsing liquid. FIG. 10 is a micrograph showing a state of a substrate after processing when IPA is used as a rinsing liquid; FIG.

Embodiments will be described below with reference to the accompanying drawings. Note that the components described in this embodiment are merely examples, and the scope of the present disclosure is not intended to be limited to them. Also, in the drawings, for ease of understanding, the dimensions or number of each part may be exaggerated or simplified as necessary.

Expressions that indicate relative or absolute positional relationships (e.g., "in one direction", "along one direction", "parallel", "perpendicular", "center", "concentric", "coaxial", etc.) Unless otherwise specified, not only expresses the positional relationship strictly, but also expresses the state of relative displacement in terms of angle or distance within the range of tolerance or equivalent function. In addition, unless otherwise specified, expressions indicating equality (e.g., “identical”, “equal”, “homogeneous”, etc.) not only express quantitatively exact equality, but also It shall also represent the state in which there is a difference in which the degree of function is obtained. In addition, expressions indicating shapes (e.g., “circular”, “square”, “cylindrical”, etc.), unless otherwise specified, not only express the shape strictly geometrically, but also The shape represents a range in which an effect can be obtained, and may have, for example, unevenness or chamfering. In addition, each expression such as "comprising", "comprising", "having", "including", or "having" a component is not an exclusive expression excluding the existence of other components. In addition, the expression "at least one of A, B and C" includes "only A", "only B", "only C", "any two of A, B and C", " All of A, B and C" are included.

<1. First Embodiment>
<1-1. Overall Configuration of Substrate Processing System>
A configuration of the substrate processing system 100 will be described with reference to FIG. FIG. 1 is a plan view schematically showing the configuration of a substrate processing system 100. FIG.

The substrate processing system 100 is a processing system that performs predetermined processing on a substrate W to be processed, and includes an interface section 110 , an indexer section 120 , a main body section 130 and a control section 140 . A substrate W to be processed in the substrate processing system 100 is, for example, a semiconductor substrate. The shape of the substrate W to be processed is, for example, a disc shape, and its size (diameter) is, for example, about 300 (mm).

The interface unit 110 is an interface for connecting the carrier C, which is a substrate container that accommodates a plurality of substrates W, to the substrate processing system 100. Specifically, for example, a load port on which the carrier C is placed. 111 are arranged in a row in the horizontal direction (three in the example shown). The carrier C may be of a type that accommodates the substrates W in an enclosed space (for example, a FOUP (Front Opening Unified Pod), a SMIF (Standard Mechanical Interface) pod, etc.), or may expose the substrates W to the outside air. type (for example, OC (Open Cassette), etc.).

The indexer section 120 is a section arranged between the interface section 110 and the main body section 130 and includes an indexer robot 121 .

The indexer robot 121 is a transport robot that transports the substrate W between the carrier C placed on each load port 111 and a main transport robot 131 (described later). It is composed of a connected arm 121b, a drive unit for extending and retracting, rotating, and raising and lowering the arm 121b. The indexer robot 121 accesses the carrier C placed on each load port 111, performs an unloading operation (that is, an operation of taking out the unprocessed substrates W stored in the carrier C with the hand 121a) and a loading operation. An operation (that is, an operation of loading the processed substrate W held by the hand 121a into the carrier C) is performed. Also, the indexer robot 121 accesses the transfer position T with the main transport robot 131 and transfers the substrate W with the main transport robot 131 .

The body section 130 includes a main transport robot 131 and a plurality of (for example, 12) processing units 132 . Here, for example, a plurality of (for example, three) processing units 132 stacked in the vertical direction constitute one tower, and the tower surrounds the main transfer robot 131 so that a plurality of processing units 132 (eg, four) are provided.

The main transport robot 131 is a transport robot that transports the substrate W between the indexer robot 121 and each processing unit 132. It includes a drive unit for turning and raising and lowering, and the like. The main transport robot 131 accesses each processing unit 132 to perform a loading operation (that is, an operation of loading the substrate W to be processed held by the hand 131a into the processing unit 132) and an unloading operation (that is, processing (operation of taking out the processed substrate W stored in the unit 132 with the hand 131a). Further, the main transport robot 131 accesses the transfer position T with the indexer robot 121 and transfers the substrate W with the indexer robot 121 .

The processing unit 132 is a device that performs a predetermined processing on the substrate W. As shown in FIG. A specific configuration of the processing unit 132 will be described later.

The control unit 140 is an element that controls the operation of each unit included in the substrate processing system 100, and is configured by, for example, a general computer having an electric circuit. Specifically, for example, as shown in FIG. 2, the control unit 140 includes a CPU (Central Processor Unit) 141 as a central processing unit responsible for data processing, and a ROM (Read Only Memory) 142 in which basic programs and the like are stored. , a RAM (random access memory) 143 used as a work area when the CPU 141 performs predetermined processing (data processing), a storage device 144 configured by a non-volatile storage device such as a flash memory, a hard disk device, etc. and a bus line 145 connected to the . The storage device 144 stores a program P that defines the processing to be executed by the control unit 140. When the CPU 141 executes the program P, the control unit 140 executes the processing defined by the program P. can be done. However, part or all of the processing executed by control unit 140 may be executed by hardware such as a dedicated logic circuit.

The control unit 140 may be configured such that a main control unit that controls the overall operation of the substrate processing system 100 and a plurality of local control units are communicably connected. In this case, each of the plurality of processing units 132 is associated with at least one local control section, and the local control section controls the operation of the corresponding processing unit 132 based on instructions from the main control section. It may be controlled. Further, when such a configuration is adopted, each of the main control section and each of the local control sections may individually include part or all of the above sections 141-145.

<1-2. Processing unit>
Next, the configuration of the processing unit 132 will be described with reference to FIG. FIG. 3 is a side view schematically showing the configuration of the processing unit 132. As shown in FIG. As described above, the main body 130 is provided with a plurality of processing units 132. If at least one of the plurality of processing units 132 has the configuration described below, good. That is, some of the plurality of processing units 132 may have a configuration different from the configuration described below.

The processing unit 132 is, for example, a processing apparatus that performs a process of stripping (removing) a resist provided on the substrate W, and corresponds to a substrate processing apparatus. The processing unit 132 is a so-called single wafer processing apparatus that processes substrates W to be processed one by one.

The processing unit 132 includes a holding section 1 , a liquid supply section 2 , a plasma generation section 3 and a guard section 4 . The processing unit 132 also includes a chamber 5 that accommodates at least some of the elements of these sections 1 to 4 (eg, base section 11, nozzles 21a and 21b, plasma reactor 31, guard 41, etc.). A downflow of clean air is formed in the internal space of the chamber 5 by the fan filter unit 51 and the like.

(Holding portion 1)
The holding unit 1 is an element that holds the substrate W to be processed, and includes, for example, a base unit 11 , a plurality of chuck pins 12 , and a rotation mechanism 13 .

The base portion 11 is a disk-shaped member having a diameter slightly larger than that of the substrate W, and is arranged in such a posture that the thickness direction thereof extends along the vertical direction. A plurality of chuck pins 12 are provided on the upper surface of the base portion 11 and arranged at intervals along the periphery of the upper surface. Each chuck pin 12 is configured to be displaced between a chuck position in contact with the peripheral edge of the substrate W and a released position away from the peripheral edge of the substrate W according to an instruction from the control unit 140. By arranging the chuck pins 12 at the chuck position, the substrate W is held above the base portion 11 in a horizontal posture (a posture in which the thickness direction of the substrate W is along the vertical direction).

The rotation mechanism 13 is a mechanism for rotating the base portion 11 . Specifically, the rotation mechanism 13 includes, for example, a shaft 13a connected at its upper end to the lower surface of the base portion 11, and a motor 13b connected to the lower end of the shaft 13a. Here, for example, an axis perpendicular to the main surface of the substrate W held on the base portion 11 and passing through the center of the main surface is defined as the rotation axis Q, and the shaft 13a rotates along this axis. It is provided coaxially with the axis Q. Then, the motor 13b rotates the shaft 13a around the rotation axis Q at the number of revolutions instructed by the control unit 140 in accordance with the instruction from the control unit 140 . As the shaft 13a is rotated by being driven by the motor 13b, the base portion 11 and, by extension, the substrate W held on the base portion 11 rotates around the rotation axis Q. As shown in FIG. Thus, the holding unit 1 including the rotation mechanism 13 (that is, the holding unit 1 capable of holding and rotating the substrate W) is also called a spin chuck or the like. Also, the base portion 11 in the spin chuck is also called a spin base.

(Liquid supply unit 2)
The liquid supply unit 2 is an element that supplies liquid to the substrate W held by the holding unit 1, and includes, for example, two nozzles (a sulfuric acid nozzle 21a and a pure water nozzle 21b) and a nozzle moving mechanism 22. Prepare.

The sulfuric acid nozzle 21a is a nozzle that ejects sulfuric acid toward the substrate W held by the holding unit 1. Specifically, for example, it is a straight nozzle having an ejection port 210a formed on one end face. A sulfuric acid supply unit 20a for supplying sulfuric acid is connected to the sulfuric acid nozzle 21a. Specifically, the sulfuric acid supply unit 20a includes, for example, a supply pipe 201a having one end connected to the sulfuric acid nozzle 21a, and a sulfuric acid supply source 202a connected to the other end of the supply pipe 201a. The sulfuric acid supply source 202a includes a sulfuric acid tank or the like that stores sulfuric acid. Further, a valve 203a and a flow rate adjusting unit 204a are inserted in the supply pipe 201a. The valve 203a is a valve that switches between supplying and stopping sulfuric acid through the supply pipe 201a, and is controlled by the controller 140. FIG. The flow rate adjusting unit 204a is composed of, for example, a mass flow controller, and under the control of the control unit 140, adjusts the flow rate of sulfuric acid flowing through the supply pipe 201a. In such a configuration, when the valve 203a is opened, a predetermined flow rate of sulfuric acid adjusted by the flow rate adjusting unit 204a is supplied from the sulfuric acid supply source 202a through the supply pipe 201a to the sulfuric acid nozzle 21a, and discharged from the discharge port 210a. be done.

The pure water nozzle 21b is a nozzle that discharges pure water toward the substrate W held by the holding unit 1. Specifically, for example, it is a straight nozzle having a discharge port 210b formed on one end face. . A pure water supply unit 20b for supplying pure water to the pure water nozzle 21b is connected to the pure water nozzle 21b. Specifically, the pure water supply unit 20b includes, for example, a supply pipe 201b having one end connected to the pure water nozzle 21b, and a pure water supply source 202b connected to the other end of the supply pipe 201b. The pure water supply source 202b includes a pure water tank that stores pure water (for example, DIW (de-ionized water)). Also, a valve 203b and a flow rate adjusting unit 204b are inserted in the supply pipe 201b. The valve 203b is a valve that switches between supplying and stopping the supply of pure water through the supply pipe 201b, and is controlled by the controller 140. FIG. The flow rate adjusting unit 204b is configured by, for example, a mass flow controller, and adjusts the flow rate of pure water flowing through the supply pipe 201b under the control of the control unit 140. FIG. In such a configuration, when the valve 203b is opened, pure water at a predetermined flow rate adjusted by the flow rate adjusting unit 204b is supplied from the pure water supply source 202b to the pure water nozzle 21b through the supply pipe 201b, and the outlet 210b.

The nozzle moving mechanism 22 is a mechanism for moving the sulfuric acid nozzle 21a and the pure water nozzle 21b between the nozzle processing position and the nozzle standby position. Here, the “nozzle processing position” of each nozzle 21a, 21b means that the liquid ejected from the ejection openings 210a, 210b of the nozzles 21a, 21b is positioned on the upper main surface of the substrate W held by the holding unit 1. Specifically, for example, it is a position above the main surface and vertically opposed to the center of the main surface (FIGS. 7 and 9). , FIG. 10). On the other hand, the "nozzle standby position" means that the two nozzles 21a and 21b are positioned at other members (the plasma reactor 31 at the plasma processing position, the hand 131a of the main transfer robot 131 that transfers the substrate W to and from the base portion 11, etc.), and specifically, for example, a position outside (outward in the radial direction) the peripheral edge of the substrate W held by the holding unit 1 when viewed from above (for example, Figure 6).

Here, a nozzle unit U is configured by connecting the sulfuric acid nozzle 21a and the pure water nozzle 21b via a connecting member or the like. Specifically, the nozzle moving mechanism 22 includes, for example, an arm that is connected to the nozzle unit U at the tip and extends substantially horizontally, a support that supports the base end of the arm, and a support that rotates the support around its axis. and a motor that rotates at The motor rotates the column about its axis at the rotation angle instructed by the control unit 140 in accordance with the instruction from the control unit 140 . When the support is rotated by being driven by the motor, the arm rotates, and the nozzle unit U connected to the tip of the arm moves along an arc-shaped locus. The position of the support and the length of the arm are defined so that the nozzle processing position and the nozzle standby position are arranged. That is, the nozzles 21a and 21b move between their respective nozzle processing positions and nozzle standby positions by moving the nozzle unit U along the arc-shaped trajectory.

(Plasma generator 3)
The plasma generation unit 3 is an element that generates plasma and irradiates the substrate W held by the holding unit 1 with the generated plasma. A mechanism 33 is provided. The plasma generator 3 is capable of generating plasma under atmospheric pressure. However, the "atmospheric pressure" referred to here is, for example, 80(%) or more of the standard atmospheric pressure and 120(%) or less of the standard atmospheric pressure.

The plasma reactor 31 is an irradiating section (plasma irradiating section) that irradiates an object (here, the substrate W held by the holding section 1) with plasma. Specifically, the plasma reactor 31 has, for example, a flat flat shape, and is positioned above the substrate W held by the holding unit 1 in such a posture that the thickness direction (the Z direction described later) is along the vertical direction. and arranged at a position facing the main surface of the substrate W in the vertical direction. The plasma reactor 31 has, for example, a circular shape in a plan view, and is approximately the same size as the substrate W to be processed (or larger than the substrate W).

The configuration of the plasma reactor 31 will be described more specifically with reference to FIG. 4 in addition to FIG. 4A and 4B are a side sectional view and a plan view schematically showing the configuration of the plasma reactor 31. FIG. Note that in FIG. 4, the holding member 315 is indicated by broken lines for the sake of clarity.

The plasma reactor 31 includes a pair of electrode portions (first electrode portion 311 and second electrode portion 312). The pair of electrode portions 311 and 312 are laminated in the thickness direction with a partition plate 313 formed of a dielectric material (for example, quartz, ceramics, etc.) interposed therebetween. Specifically, the first electrode portion 311 is provided on one side in the thickness direction of the disk-shaped partition plate 313 , and the second electrode portion 312 is provided on the other side. Hereinafter, for convenience of explanation, the direction in which the first electrode portion 311, the partition plate 313, and the second electrode portion 312 are stacked is referred to as the "Z direction." In a plane perpendicular to the Z direction, the extending direction of linear electrodes 311a and 312a, which will be described later, is defined as the "X direction", and the direction perpendicular to the Z direction and the X direction is defined as the "Y direction".

The first electrode portion 311 includes a plurality of linear electrodes (first linear electrodes) 311a made of an appropriate conductive material (eg, tungsten), and a collective electrode made of an appropriate conductive material (eg, aluminum). It is connected via (first collective electrode) 311b, and has a comb shape as a whole. Specifically, for example, each of the first linear electrodes 311a is a linear (rod-shaped) electrode, and is arranged in such a posture that the longitudinal direction thereof extends along the X direction. In addition, the plurality of first linear electrodes 311a are arranged in the arrangement direction (in the example of the figure, the Y direction which is perpendicular to the X direction) intersecting the extending direction (X direction) of each first linear electrode 311a. are arranged at regular intervals along the line. Each first linear electrode 311a is preferably accommodated within a dielectric tube 314, which is a tubular member made of a dielectric material (eg, quartz, ceramics, etc.). On the other hand, the first collective electrode 311b is a long plate-shaped electrode extending in an arc shape in plan view. The first collective electrode 311b is arranged in such a posture that the bulging direction is directed to one side (-X side in the example of the figure) of the extending direction of each first linear electrode 311a, and , the −X side ends of the first linear electrodes 311a are connected.

As with the first electrode portion 311, the second electrode portion 312 includes a plurality of linear electrodes (second linear electrodes) 312a formed of an appropriate conductive material (eg, tungsten). It is connected via a collective electrode (second collective electrode) 312b made of aluminum), and has a comb shape as a whole. Specifically, for example, each of the second linear electrodes 312a is a linear electrode, and is arranged in such a posture that the longitudinal direction is along the X direction. In addition, the plurality of second linear electrodes 312a are arranged in the arrangement direction (the Y direction, which is the direction orthogonal to the X direction in the example of the figure) that intersects the extending direction (X direction) of each second linear electrode 312a. are arranged at regular intervals along the line. Each second linear electrode 312a is preferably housed within a dielectric tube 314, which is a tubular member made of a dielectric material (eg, quartz, ceramics, etc.). On the other hand, the second collective electrode 312b is a long plate-shaped electrode extending in an arc shape in plan view. The second collective electrode 312b is arranged in such a posture that the bulging direction is directed to the opposite side (+X side in the example of the figure) of the bulging direction of the first collective electrode 311b. The ends of the two-line electrodes 312a on the +X side are connected.

The first electrode portion 311 is arranged at a position such that the first collective electrode 311b extends outside and close to the peripheral edge of the partition plate 313 when viewed from the Z direction, and is located on the +Z side of the partition plate 313. provided in On the other hand, the second electrode portion 312 is arranged at a position such that the second collective electrode 312b extends outside and close to the peripheral edge of the partition plate 313 when viewed from the Z direction. It is provided on the -Z side. At this time, the second linear electrodes 312a are arranged between the adjacent first linear electrodes 311a when viewed from the Z direction. That is, the first linear electrodes 311a and the second linear electrodes 312a are alternately arranged along the Y direction within the main surface of the partition plate 313 when viewed from the Z direction without overlapping each other.

The first electrode portion 311 and the second electrode portion 312 (hereinafter also referred to as “electrode assembly”) stacked with the partition plate 313 interposed therebetween are held together by a holding member 315 made of an insulating material (for example, fluorine-based resin, etc.). , are held together. Specifically, the holding member 315 includes, for example, a pair of ring-shaped holding rings 315a and 315b in plan view. One retaining ring 315a is provided in contact with one side of the electrode assembly (eg, the first electrode section 311 side), and the other retaining ring 315b is provided on the other side of the electrode assembly (eg, the second electrode section 311 side). The electrode assembly is sandwiched between the pair of retaining rings 315a and 315b by connecting the retaining rings 315a and 315b to each other. retained in this.

The power supply 32 is a plasma power supply for generating plasma and is connected to the plasma reactor 31 . Specifically, one of the pair of wires extending from the power supply 32 is connected to the first electrode portion 311 (specifically, the first collective electrode 311b), and the other is connected to the second electrode portion 312 (specifically, the , to the second collective electrode 312b).

The power supply 32 is controlled by the control unit 140 and applies a predetermined voltage (plasma voltage) between the first electrode unit 311 and the second electrode unit 312 according to instructions from the control unit 140 . Then, an electric field is generated between the first linear electrode 311a and the second linear electrode 312a, and discharge is generated between the first linear electrode 311a and the second linear electrode 312a. Since the dielectric partition plate 313 exists between the linear electrodes 311a and 312a, this discharge is a so-called dielectric barrier discharge. The discharge causes the gas around the first linear electrode 311a and the second linear electrode 312a to become plasma. That is, plasma is generated (lighted). In other words, the power source 32 applies a voltage to the extent that the surrounding gas becomes plasma as a voltage for plasma between the two electrode portions 311 and 312 .

Specifically, the power supply 32 may be, for example, an AC power supply, and an AC voltage may be applied between the electrodes 311 and 312 as a voltage for plasma. Further, the power supply 32 may specifically include, for example, a switching power supply circuit such as an inverter circuit and have a function as a high frequency power supply. It may be applied between the electrode portions 311 and 312 . Furthermore, the power supply 32 may include, for example, a pulse generator and have a function as a pulse power supply, and during the ON period of the pulse signal generated by the pulse generator at a predetermined cycle, both electrodes A high frequency voltage may be applied between the portions 311 and 312 . In this case, the plasma is lit mainly during the ON period of the pulse signal. As an example, the voltage value of the plasma voltage (amplitude value of the high frequency voltage) is about ten and several kV or more. Further, when the plasma voltage is applied during the ON period of each cycle defined by the pulse wave, the frequency of the pulse wave is about several tens (kHz).

The plasma reactor moving mechanism 33 is a mechanism for moving (lifting) the plasma reactor 31 between the plasma processing position and the standby position. Here, the “plasma processing position” is a position where the plasma reactor 31 irradiates the substrate W held by the holding unit 1 with plasma. A position where the distance between the plasma reactor 31 and the substrate W is sufficiently small (for example, a position where the distance is about several millimeters) to the extent that active species can act on the substrate W (FIG. 8). . On the other hand, the “standby position” is a position where the plasma reactor 31 does not irradiate the substrate W held by the holding unit 1 with plasma. This is the position where the separation distance between the two is sufficiently large to the extent that it does not act (for example, FIG. 6).

Specifically, the plasma reactor moving mechanism 33 includes, for example, an elevating plate that is connected to the plasma reactor 31 at its tip and extends substantially horizontally, and a motor. A cam is provided between the motor and the lift plate to convert the rotational motion of the motor into the lift motion of the lift plate. Therefore, when the motor rotates by the rotation angle instructed by the control unit 140 in accordance with the instruction from the control unit 140, the elevator plate (and the plasma reactor 31 connected thereto) rotates according to the rotation angle. Ascend (or descend) by distance. However, the configuration of the plasma reactor moving mechanism 33 is not limited to this, and can be realized by various driving mechanisms that achieve vertical movement. For example, the plasma reactor moving mechanism 33 may include a ball screw mechanism and a motor for applying a driving force thereto, or may include an air cylinder.

(Guard part 4)
The guard section 4 is an element that receives the processing liquid and the like that scatter from the substrate W held by the holding section 1, and includes a guard 41 and a guard moving mechanism 42, for example.

The guard 41 includes a tubular portion 41a, an inclined portion 41b, and an extending portion 41c. The cylindrical portion 41 a is a cylindrical portion and is provided so as to surround the holding portion 1 . The inclined portion 41b is provided so as to continue from the upper edge of the cylindrical portion 41a, and is inclined inward as it goes vertically upward. The extending portion 41c is a plate ring-shaped portion, and is provided so as to extend inward in a substantially horizontal plane from the upper end edge of the inclined portion 41b.

The guard moving mechanism 42 is a mechanism for moving (lifting) the guard 41 between the guard processing position and the guard standby position. Here, the "guard processing position" is a position where the guard 41 receives the processing liquid or the like that scatters from the substrate W held by the holding section 1. Specifically, for example, the extending portion 41c The position is such that it is positioned above the substrate W (eg FIG. 7). On the other hand, the "guard standby position" is a position where the guard 41 does not interfere with other members (such as the hand 131a of the main transport robot 131 that transfers the substrate W to and from the base portion 11). Specifically, for example, the extending portion 41c is positioned below the substrate W held by the holding portion 1 (eg, FIG. 6).

The guard moving mechanism 42 can be realized by various driving mechanisms that realize vertical movement. Specifically, for example, the guard moving mechanism 42 may include a ball screw mechanism, a motor for applying a driving force to the ball screw mechanism, or the like, or may include an air cylinder or the like.

Below the guard 41 , a liquid drain section 43 is provided for draining the processing liquid and the like received on the inner peripheral surface of the guard 41 . Specifically, the drain part 43 includes, for example, a cup 431 provided below the guard 41, a drain pipe 432 connected to the cup 431, and the like. The processing liquid received by the inner peripheral surface and flowing down along the inner peripheral surface is received by the cup 431 and is drained from the drain pipe 432 .

Further, an exhaust portion 44 for exhausting gas, mist, etc. flowing along the inner peripheral surface of the guard 41 is provided on the outer side of the guard 41 . Specifically, the exhaust part 44 includes, for example, a peripheral wall part 441 provided so as to surround the guard 41 from the outside, an exhaust pipe 442 connected to the peripheral wall part 441, and the like, and is arranged at the guard processing position. Gas, mist, etc., which is received by the inner peripheral surface of the guard 41 and flows down along the inner peripheral surface, is received by the peripheral wall portion 441 and is exhausted from the exhaust pipe 442 .

<1-3. Process Flow>
Next, the flow of processing performed by the processing unit 132 will be described with reference to FIGS. 5 and 6 to 10 in addition to FIG. FIG. 5 is a diagram showing the flow of the processing. Each of FIGS. 6 to 10 is a diagram for explaining each processing step, and schematically shows the state of each part in the processing step.

In the following description, the substrate W to be processed is, for example, a substrate W after etching or ion implantation has been performed by providing a resist as a mask on at least one of its principal surfaces. , a series of processes for removing (peeling) the unnecessary resist. A series of processes described below are performed by the control unit 140 controlling each unit provided in the processing unit 132 . Also, a series of processes described below are usually performed repeatedly. That is, when a series of processes for one substrate W is completed, another new substrate W is subsequently subjected to the series of processes.

Step S<b>1 : Holding Step First, the substrate W to be processed is held by the holding section 1 . That is, when the main transfer robot 131 inserts the hand 131a holding the substrate W to be processed into the chamber 5 and loads the substrate W into the processing unit 132, the holding unit 1 moves the loaded substrate W through the resist. is held in a horizontal position so that the main surface on which is provided faces upward (FIG. 6). The nozzles 21a and 21b, the plasma reactor 31, and the guard 41 are placed at their standby positions so as not to interfere with the hand 131a during this process.

Step S2: Liquid Film Forming Step Subsequently, sulfuric acid as a processing liquid is supplied to the substrate W held in the holding unit 1 to form a liquid film F of sulfuric acid on the upper surface of the substrate W (FIG. 7). Specifically, for example, the nozzle moving mechanism 22 moves the sulfuric acid nozzle 21a from the nozzle waiting position to the nozzle processing position. When the sulfuric acid nozzle 21a is placed at the nozzle processing position, the valve 203a provided on the supply pipe 201a is opened. Then, the sulfuric acid stored in the sulfuric acid supply source 202a is supplied to the sulfuric acid nozzle 21a through the supply pipe 201a at a predetermined flow rate (for example, 300 (ml/min)) adjusted by the flow rate adjustment section 204a, and discharged. It is discharged from the outlet 210a. The sulfuric acid discharged from the sulfuric acid nozzle 21a arranged at the processing position lands on a predetermined position (for example, the center of the main surface) on the upper main surface of the substrate W held by the holding unit 1 . The sulfuric acid that has landed on the main surface of the substrate W spreads toward the peripheral edge of the substrate W, forming a liquid film F of sulfuric acid covering substantially the entire main surface.

It is preferable that the rotation mechanism 13 rotates the holder 1 (and thus the substrate W held therein) at a predetermined number of rotations at least while sulfuric acid is being discharged from the sulfuric acid nozzle 21a. As a result, the sulfuric acid that has landed on the upper main surface of the substrate W quickly spreads toward the peripheral edge of the substrate W due to the centrifugal force, and a sulfuric acid liquid film F covering substantially the entire main surface is quickly formed. .

Moreover, it is preferable that the guard moving mechanism 42 arranges the guard 41 at the guard processing position at least while the substrate W is being rotated. As a result, the sulfuric acid scattered from the peripheral edge of the substrate W is received by the inner peripheral surface of the guard 41, flows down along the inner peripheral surface, is further received by the cup 431, and is drained from the drain pipe 432. be. The same applies to the rinsing step (step S7) and the drying step (step S8), which will be described later.

After a predetermined time (for example, about 5 to 10 seconds) has elapsed since the sulfuric acid nozzle 21a started discharging sulfuric acid as the treatment liquid, the valve 203a is closed and the discharging of sulfuric acid is stopped. After that, the rotation mechanism 13 reduces the rotation speed of the substrate W to a sufficiently low rotation speed (preferably 50 rpm or less), or stops the rotation. The liquid film F is stabilized on the substrate W by rotating the substrate W with the liquid film F formed thereon at a sufficiently low number of revolutions for a predetermined time (or maintaining the state where the rotation is stopped). and held (so-called paddle processing).

Step S<b>3 : Voltage Application Start Step Subsequently, application of a predetermined voltage (voltage for plasma generation) from the power supply 32 to the plasma reactor 31 is started. By applying a predetermined voltage to the plasma reactor 31, the gas (here, air) around the plasma reactor 31 is turned into plasma to generate plasma. This plasma contains various active species (when the gas surrounding the plasma is air, for example, active species such as oxygen radicals, hydroxyl radicals, and ozone gas). It changes depending on the type of gas existing around the reactor 31 and the like.

Step S4: Lowering Step Subsequently, the plasma reactor moving mechanism 33 moves (lowers) the plasma reactor 31 from the standby position to the plasma processing position. Active species in the plasma generated around the plasma reactor 31 are deactivated in a relatively short time. Most of the active species are deactivated at positions away from the reactor 31 . Therefore, in this process, the plasma reactor 31 is brought close to the substrate W, and the distance between the two is made sufficiently small so that at least the amount of active species required for plasma processing can act on the substrate W.

Either the voltage application start step (step S3) or the lowering step (step S4) may be performed first, or may be performed in parallel. That is, the voltage application to the plasma reactor 31 may be started at any timing before, during, or after the plasma reactor 31 is lowered. As described below, the plasma processing of the substrate W progresses in a state where the plasma reactor 31 to which voltage is applied is placed at the plasma processing position, and both the voltage application start step and the voltage drop step are performed. Thus, the plasma processing of the substrate W is started.

In a state where the plasma reactor 31 to which a voltage is applied is arranged at the plasma processing position (FIG. 8), the plasma reactor is arranged so as to face the main surface of the substrate W held by the holder 1. Plasma is irradiated from 31, and the plasma processing for the substrate W progresses. In this plasma treatment, the plasma generated around the plasma reactor 31 acts on the liquid film F of sulfuric acid formed on the main surface of the substrate W, so that the sulfuric acid treatment performance is enhanced. Specifically, active species in the plasma react with sulfuric acid to generate caro's acid (peroxomonosulfuric acid: H ₂ SO ₅ ) with high processing performance (here, oxidizing power). The generated Caro's acid and the active species in the plasma act on the resist provided on the main surface of the substrate W, thereby oxidizing and stripping (removing) the resist. That is, here, the resist stripping process is performed by plasma processing.

It is preferable that the rotation mechanism 13 rotates the substrate W at a predetermined number of rotations while the substrate W is subjected to plasma processing. As a result, the entire upper main surface of the substrate W is uniformly irradiated with plasma, and the uniformity of processing within the main surface is improved. However, the rotation speed at this time is set to a sufficiently low speed (for example, about 30 to 50 rpm) so that the liquid film F provided on the substrate W is not disturbed.

Step S5: Step of Stopping Voltage Application After the plasma processing (that is, resist stripping processing) has progressed for a predetermined processing time, the voltage application from the power source 32 to the plasma reactor 31 is stopped at an appropriate timing thereafter. . This stops plasma generation (that is, extinguishes the plasma).

Step S6: Ascending process When the plasma processing proceeds for a predetermined processing time, the plasma reactor moving mechanism 33 moves (raises) the plasma reactor 31 from the plasma processing position to the standby position at an appropriate timing thereafter. ).

Either the voltage application stop step (step S5) or the rising step (step S6) may be performed first, or may be performed in parallel. That is, the voltage application to the plasma reactor 31 may be stopped at any timing before, during, or after the plasma reactor 31 is raised. As described above, the plasma processing of the substrate W proceeds in a state where the plasma reactor 31 to which voltage is applied is placed at the plasma processing position. By doing so, the plasma processing of the substrate W is completed.

Step S7: Rinsing Step When the plasma processing (that is, resist stripping processing) on the substrate W is completed, subsequently, the rinse liquid is supplied to the substrate W after the plasma processing is completed, so that the rinse liquid is brought into contact with the substrate W. A process (rinsing process) is performed to wash away the liquid film F on the substrate W (FIGS. 9 and 10). This step will be described in detail later.

Step S8: Drying Step When the rinsing process is completed, the rotation mechanism 13 rotates the substrate W held by the holding unit 1 at a sufficiently high rotation speed (for example, about 1000 to 2000 rpm) for a predetermined time (for example, 30 seconds). degree), rotate. By rotating at a sufficiently high rotational speed, a large centrifugal force acts on the liquid on the substrate W, and the liquid is shaken off around the substrate W. FIG. The substrate W is thereby dried (so-called spin drying).

When the substrate W is dried, the nozzles 21 a and 21 b and the guard 41 are arranged at their standby positions, and the main transfer robot 131 unloads the substrate W held by the holding section 1 . A series of processes for the substrate W is thereby completed.

<1-4. Rinse process>
<1-4-1. Rinse liquid>
As described above, when the plasma processing of the substrate W is completed, the rinsing step of supplying the rinsing liquid to the substrate W to bring the rinsing liquid into contact with the substrate W to wash away the liquid film F is performed. Here, the peeled resist is dissolved in the liquid film F of sulfuric acid held on the substrate W at the stage where the plasma processing (that is, the resist stripping processing) is completed. The solubility (saturated solubility) of the resist dissolved in the liquid film F fluctuates under the influence of physical quantities of the liquid film F (specifically, pH value, temperature, for example). Therefore, when the rinsing liquid is brought into contact with the liquid film F in the rinsing step, the physical quantity is greatly changed, and as a result, the solubility is changed (decreased). be. The deposited resist may adhere to the substrate W and become particles.

Here, the larger the difference in the physical quantity (physical quantity affecting the solubility) between the liquid film F and the rinse liquid with which the rinse liquid is in contact, growing. Conversely, the smaller the difference in the physical quantity, the smaller the range of change in solubility caused by contact with the rinse liquid. Therefore, here, with respect to the physical quantity, by using a rinsing liquid having a sufficiently small difference from the liquid film F, the range of change in the solubility of the resist caused by contact with the rinsing liquid is expressed as Keep it within a range (permissible range) that does not cause it. That is, in the rinsing step, the substrate W after the stripping process is wetted with a rinsing liquid such that the range of change in solubility of the resist dissolved in the liquid film F is within an allowable range in which the resist is not precipitated. Let

However, the phrase "not depositing resist" here does not necessarily mean only that the amount of resist deposited is zero, but means not depositing resist in excess of the allowable deposition amount. there is Further, the "permissible precipitation amount" is specifically an amount of resist precipitation such that even if that amount of resist precipitates, the effect of suppressing the generation of particles on the substrate W after processing is recognized. be. That is, as long as the effect of suppressing the generation of particles is recognized on the substrate W after processing, it can be considered that the deposition amount of the resist is within the allowable deposition amount.

Specifically, in this rinsing step, the pH value, which is one of the physical quantities that affect the solubility, is used as an index, and an acidic liquid having a sufficiently small difference in pH value from the liquid film F is used as the rinsing liquid. By doing so, the range of change in solubility caused by contact with the rinse liquid is kept within an allowable range. That is, when the maximum pH difference between the rinsing liquid and the liquid film F that allows the change in solubility to fall within the allowable range is called the "maximum allowable pH difference", the liquid film An acidic liquid whose pH value difference between F and F is equal to or less than the maximum allowable pH difference is used as a rinse (first rinse). With such a rinsing liquid, even if the rinsing liquid comes into contact with the liquid film F after the resist stripping process, the solubility of the rinsing liquid changes only within an allowable range. Therefore, the resist dissolved in the liquid film F is not precipitated. That is, with such a rinse liquid, the liquid film F on the substrate W can be washed away without depositing the resist.

The allowable range of solubility variation is defined by various processing conditions (for example, the type of resist, the amount of resist stripped (that is, dissolved in the liquid film F), the allowable deposition amount, etc.). Therefore, for example, the allowable range of solubility change under given treatment conditions is specified by experiments, theoretical calculations, etc., and the maximum allowable pH difference can be derived based on this. Then, a liquid whose pH value difference with the liquid film F is equal to or less than the derived maximum allowable pH difference may be selected as the rinsing liquid.

However, as described above, the range of change in solubility caused by contact with the rinse liquid is also affected by the temperature difference between the liquid film F and the rinse liquid. , the width of change in solubility becomes smaller. Therefore, as schematically shown in FIG. 11, the maximum value of the difference in pH value between the rinse liquid and the liquid film F (the maximum allowable pH difference ) decreases as the temperature difference between the rinse liquid and the liquid film F increases. For example, the temperature of the liquid film F after the plasma treatment is increased to, for example, about 250° C. by receiving heat from the plasma. , the maximum allowable pH difference is approximately "2" when supplied and brought into contact with the liquid at room temperature (about 23°C) without heating (that is, with a relatively large temperature difference). That is, when the pH value difference between the liquid film F and the liquid film F is "2" or less (for example, when the treatment liquid used to form the liquid film F is sulfuric acid with a pH value of "1", If a liquid having a pH value of "3" or less is used as the rinse liquid, even if it is supplied to the heated liquid film F without being heated and brought into contact with the liquid film F, the rinse liquid does not come into contact with the liquid. It is possible to keep the width of the change in solubility caused by

<1-4-2. Flow of Processing Related to Rinsing Step>
The flow of processing related to the rinse step based on the above concept will be described with reference to FIG. 12 in addition to FIGS. FIG. 12 is a diagram for explaining the flow of processing related to the rinsing process.

Step S71: First rinse step (acid rinse step)
First, sulfuric acid as a first rinse is supplied to the substrate W after plasma processing (that is, resist stripping) is completed, so that the substrate W is brought into contact with the first rinse (FIG. 9). Specifically, for example, the nozzle moving mechanism 22 moves the sulfuric acid nozzle 21a from the nozzle waiting position to the nozzle processing position. When the sulfuric acid nozzle 21a is placed at the nozzle processing position, the valve 203a provided on the supply pipe 201a is opened. Then, as described above, the sulfuric acid stored in the sulfuric acid supply source 202a is at a predetermined flow rate (for example, 200 to 500 (ml/min) adjusted by the flow rate adjusting unit 204a, such as 300 (ml/min) as an example. ), the sulfuric acid is supplied to the sulfuric acid nozzle 21a through the supply pipe 201a and discharged from the discharge port 210a. The sulfuric acid discharged from the sulfuric acid nozzle 21a arranged at the processing position lands on a predetermined position (for example, the center of the main surface) on the upper main surface of the substrate W held by the holding unit 1 . As a result, the substrate W is supplied (wetted) with sulfuric acid as the first rinse.

Thus, in the first rinsing step, the sulfuric acid stored in the sulfuric acid supply source 202a is used as the first rinsing liquid. That is, in the liquid film forming step (step S2), the liquid supplied to the substrate W as the processing liquid when forming the liquid film F, and the liquid supplied to the substrate W as the first rinse liquid in the first rinsing step. are both sulfuric acid and have the same concentration. Needless to say, in this case, the difference in pH value between the first rinse liquid and the liquid film F is such that the first rinse liquid is supplied to the heated liquid film F without being heated and brought into contact with the liquid film F. It is well below the maximum allowable pH difference of "2" and is almost zero. Therefore, when the first rinse liquid contacts the liquid film F, the pH value hardly changes. Therefore, the width of change in solubility caused by contact with the first rinse liquid is sufficiently small, and deposition of the resist is sufficiently avoided.

As shown in FIG. 12, here, when the sulfuric acid nozzle 21a starts discharging sulfuric acid as the first rinse liquid, the rotating mechanism 13 rotates the substrate W held by the holding unit 1. Rotate while increasing the number step by step. That is, while sulfuric acid is discharged from the sulfuric acid nozzle 21a toward the substrate W, the substrate W is rotated while increasing the rotational speed stepwise. Specifically, for example, the rotation mechanism 13 takes a predetermined time (first time) T1 (for example, about 3 to 5 seconds) to rotate the substrate W at a sufficiently low (low speed) first rotation. The number R1 (for example, 30 to 50 rpm) is gradually increased to a higher second rotation speed R2 (for example, 100 to 1500 rpm, about 500 rpm as an example). When the rotation speed reaches the second rotation speed R2, the rotation mechanism 13 continues to rotate the substrate W at the second rotation speed R2. It should be noted that any aspect of increasing the number of revolutions in stages may be employed. For example, it may be raised linearly (at a constant rate of increase) as illustrated, or may be raised stepwise.

As the substrate W is rotated, the sulfuric acid discharged from the sulfuric acid nozzle 21a and deposited on the upper main surface of the substrate W as the first rinse quickly spreads toward the peripheral edge of the substrate W due to centrifugal force. To go. On the other hand, the sulfuric acid liquid film F covering substantially the entire main surface of the substrate W (that is, the sulfuric acid liquid film F in which the stripped resist is dissolved) is replaced by the newly supplied sulfuric acid as the first rinse liquid ( That is, it is swept outward by clean sulfuric acid that does not dissolve the resist, and is quickly discharged to the periphery of the substrate W. FIG. That is, the sulfuric acid liquid film F covering the substrate W when the plasma processing is finished is replaced with the sulfuric acid as the first rinse liquid.

If the number of rotations of the substrate W is increased from the first number of rotations R1 to the second number of rotations R2 not in stages but at once (intentionally without taking time), the liquid will flow from the peripheral side of the substrate W. The speed at which the liquid is supplied from the center side of the substrate W cannot catch up with the speed at which the liquid is discharged, and a gas-liquid interface appears in the vicinity of the peripheral edge of the substrate W. That is, in the vicinity of the peripheral edge of the substrate W, an exposed portion (that is, a dry portion) is generated without being covered with the liquid. Particles and the like tend to adhere to such portions, and the cleanliness of the substrate W tends to deteriorate. According to the above-described configuration in which the number of revolutions is increased stepwise, such a gas-liquid interface is less likely to appear on the substrate W, so the cleanliness of the substrate W is less likely to deteriorate. That is, the liquid film F on the substrate W can be replaced with sulfuric acid as the first rinsing liquid without lowering the cleanliness of the substrate W. FIG.

When a predetermined time (second time) T2 (for example, about 10 seconds) elapses after the sulfuric acid nozzle 21a starts discharging sulfuric acid as the first rinse liquid, the valve 203a is closed to stop discharging the sulfuric acid. be done. As a result, the first rinsing step is completed, and the sulfuric acid liquid film F covering the substrate W when the plasma processing is completed is sufficiently replaced with the sulfuric acid as the first rinsing liquid.

Step S72: Second rinsing step Subsequently, pure water as a second rinsing liquid is supplied to the substrate W after completion of the first rinsing process, thereby bringing the second rinsing liquid into contact with the substrate W (Fig. 10). Specifically, for example, the nozzle moving mechanism 22 moves the pure water nozzle 21b from the nozzle waiting position to the nozzle processing position. When the pure water nozzle 21b is placed at the nozzle processing position, the valve 203b provided on the supply pipe 201b is opened. Then, the pure water stored in the pure water supply source 202b is supplied to the pure water nozzle 21b through the supply pipe 201b at a predetermined flow rate adjusted by the flow rate adjusting section 204b, and is discharged from the outlet 210b. . The pure water discharged from the pure water nozzle 21b arranged at the processing position lands at a predetermined position (for example, the center of the main surface) on the upper main surface of the substrate W held by the holding unit 1. do. As a result, pure water as the second rinse liquid is supplied to (contacts with) the substrate W. As shown in FIG.

Thus, in the second rinse step, the pure water stored in the pure water supply source 202b is used as the second rinse liquid. That is, the pH value of the second rinse is significantly different from the pH value of the sulfuric acid supplied to the substrate W as the first rinse. Therefore, by supplying the pure water as the second rinse liquid, the sulfuric acid as the first rinse liquid remaining on the substrate W is diluted, and the pH value greatly changes (increases). However, since the first rinse liquid remaining on the substrate W at this time is clean sulfuric acid in which the resist does not dissolve, the resist does not deposit even if the pH value changes significantly.

As shown in FIG. 12, the discharge of sulfuric acid as the first rinse from the sulfuric acid nozzle 21a is stopped, and instead, the discharge of pure water from the pure water nozzle 21b as the second rinse is started. Furthermore, while the discharge is continued, the rotation mechanism 13 continues to rotate the substrate W held by the holding section 1 at the second rotation speed R2. In other words, the rotating mechanism 13 is rotated until the second rinsing process ends (that is, until the drying process (step S8) starts) after the number of revolutions of the substrate W reaches the second number of revolutions R2 in the first rinsing process. ), and continue to rotate the substrate W at the second rotation speed R2. As a result, the pure water as the second rinse liquid discharged from the pure water nozzle 21b and deposited on the upper main surface of the substrate W quickly spreads toward the peripheral edge of the substrate W due to the centrifugal force. The sulfuric acid remaining on the W main surface as the first rinse is replaced with pure water as the second rinse.

When the pure water nozzle 21b starts discharging the pure water as the second rinse liquid, the valve 203b is closed and the pure water discharge is stopped when a predetermined time elapses. As a result, the second rinse process is completed, and the sulfuric acid as the first rinse liquid remaining on the substrate W when the first rinse process is completed is sufficiently washed away by the pure water as the second rinse liquid. be

After the rinsing process is completed, the drying process (step S8) is performed.

<1-5. State of substrate after treatment>
In FIG. 20, DIW is used as the rinsing liquid that is first brought into contact with the substrate W after the resist stripping process is completed, and other than this, the same process as the above series of processes (steps S1 to S8) is performed. A microscopic image of the upper surface of the substrate W after processing is shown (first comparative example). In addition, in FIG. 21, IPA (isopropyl alcohol) was used as a rinse liquid that was first brought into contact with the substrate W after the resist stripping process, and the same process as the series of processes described above was performed except for this. A microscope image of the upper surface of the substrate W after processing is shown in the case (second comparative example). As is clear from these microscope images, in either case of using DIW or IPA as the rinsing liquid that is first brought into contact with the substrate W after the resist stripping process is completed, the substrate W after the process has It can be seen that particles are generated.

On the other hand, in FIG. 13, sulfuric acid having the same concentration as the processing liquid for forming the liquid film F is used as the rinsing liquid (first rinsing liquid) that is first brought into contact with the substrate W after the resist stripping process is completed. In this case, a microscopic image of the upper surface of the substrate W after processing (after the above-described series of processing (steps S1 to S8) has been performed) is shown. As is clear from this microscope image, when sulfuric acid having the same concentration as the processing liquid is used as the rinsing liquid that is first brought into contact with the substrate W after the resist stripping process is completed, the substrate W after the processing has It can be seen that there are no particles.

Both DIW and IPA are neutral liquids and have a large difference in pH value from the liquid film F. The reason why particles are generated on the substrate W after the treatment when such a neutral liquid is used as the rinse liquid with which the substrate W is first brought into contact after the resist stripping process is finished is that the rinse liquid When the liquid was supplied and brought into contact with the substrate W, the pH value rapidly increased, and along with this, the solubility of the resist dissolved in the liquid film F decreased, and as a result, the resist could not be completely dissolved. Presumably, this is due to deposition of the resist (so-called pH shock). On the other hand, when sulfuric acid having the same concentration as the processing liquid forming the liquid film F is used as the rinsing liquid that is first brought into contact with the substrate W after the resist stripping process is completed, the substrate W after the processing is The reason why particles are not generated in the resist is that when the rinse liquid contacts the liquid film F, the pH value hardly changes. This is probably because the precipitation of was not induced.

<1-6. Effect>
The substrate processing method according to the above embodiment includes a liquid film forming step (step S2) of supplying an acidic processing liquid to the substrate W provided with a resist to form a liquid film F of the processing liquid (step S2); A plasma treatment step of irradiating plasma onto the substrate W holding the F to proceed with the resist stripping process, and a plasma treatment step in which the resist dissolved in the liquid film F is applied to the substrate W after the stripping process is completed. and a rinsing step (step S7) of contacting the resist with a rinsing liquid (first rinsing liquid) such that the width of change in solubility is kept within an allowable range in which the resist is not precipitated.

According to this configuration, the liquid film F in which the stripped resist is dissolved is formed on the substrate W by contacting (supplying) the first rinse liquid to the substrate W after the resist stripping process is completed. washed away from Here, the first rinsing liquid is such that the change width of the solubility of the resist dissolved in the liquid film F is kept within an allowable range in which the resist is not precipitated. In other words, even if the first rinse liquid contacts the liquid, the solubility changes only within an allowable range in which the resist is not precipitated. Therefore, deposition of the resist is not induced by contact with the first rinse liquid. Therefore, generation of particles on the substrate W after processing is suppressed.

More specifically, in the above-described embodiment, by using an acidic liquid whose pH value difference with the liquid film F is equal to or less than the maximum allowable pH difference as the first rinse liquid, the solubility change width within an acceptable range. According to this configuration, since the first rinse is selected using the pH value as an index, the first rinse is such that the range of change in solubility when the first rinse is in contact with the liquid can be kept within an allowable range. The liquid can be selected easily and appropriately.

More specifically, in the above embodiment, the first rinsing liquid is a liquid that has a pH value difference of 2 or less with respect to the liquid film F. According to this configuration, it is possible to sufficiently reduce the width of change in solubility when the first rinse liquid is brought into contact with the first rinse liquid, and it is possible to sufficiently suppress the generation of particles.

Moreover, in the above embodiment, both the first rinse liquid and the treatment liquid are sulfuric acid. According to this configuration, compared to the case where different types of liquids are used for the first rinse liquid and the processing liquid, the piping system required for supplying the liquids is simplified.

In particular, in the above embodiment, the first rinse liquid and the treatment liquid are sulfuric acid of the same concentration. According to this configuration, when the first rinse liquid contacts the liquid film F, the pH value hardly changes. Therefore, it is possible to make the width of change in solubility particularly small when the rinsing liquid comes into contact with the liquid, and it is possible to sufficiently suppress the generation of particles.

Further, in the above-described embodiment, in the rinsing step, the substrate W is discharged while the first rinse liquid is discharged from the nozzle (sulfuric acid nozzle) 21a toward the substrate W (that is, while the first rinse liquid is poured over the substrate W). is rotated while increasing the number of revolutions step by step. As described above, if the number of revolutions is increased all at once instead of stepwise, the speed at which the liquid is supplied onto the substrate W cannot catch up with the speed at which the liquid is discharged from the substrate W. A gas-liquid interface appears, and there is a possibility that an exposed portion is generated without being covered with the liquid. Particles and the like tend to adhere to such portions, and the cleanliness of the substrate W tends to deteriorate. According to the above-described configuration in which the number of revolutions is increased stepwise, such a gas-liquid interface is less likely to appear on the substrate W, so the cleanliness of the substrate W is less likely to deteriorate. That is, the liquid film F in which the stripped resist is dissolved can be replaced with the first rinse liquid without lowering the cleanliness of the substrate W. FIG.

<2. Second Embodiment>
<2-1. Rinse liquid>
In the first embodiment, the pH value, which is one of the physical quantities that affect the solubility, is used as an index. is used as the rinse solution, the range of change in solubility caused by contact with the rinse solution is kept within an allowable range.

In contrast, in this embodiment, temperature, which is another physical quantity that affects the solubility, is used as an index, and a liquid having a sufficiently small difference in temperature from the liquid film F is used as the rinse liquid. To keep the range of change in solubility caused by contact with the liquid within an allowable range. That is, when the maximum temperature difference between the rinsing liquid and the liquid film F that allows the change in solubility to fall within the allowable range is called the "maximum allowable temperature difference", the liquid film F A liquid in which the temperature difference between the With such a rinsing liquid, even if the rinsing liquid comes into contact with the liquid film F after the resist stripping process, the solubility of the rinsing liquid changes only within an allowable range. Therefore, the resist dissolved in the liquid film F is not precipitated. That is, with such a rinse liquid, the liquid film F on the substrate W can be washed away without depositing the resist.

As described above, the allowable range of variation in solubility is defined by various processing conditions. Therefore, for example, the allowable range of solubility change under given processing conditions is specified by experiments, theoretical calculations, etc., and the maximum allowable temperature difference can be derived based on this. Then, the liquid whose temperature is adjusted so that the temperature difference with the liquid film F is equal to or less than the derived maximum allowable temperature difference may be used as the rinse liquid.

However, as described above, the range of change in solubility caused by contact with the rinse solution is also affected by the difference in pH value between the liquid film F and the rinse solution. The smaller the value, the smaller the width of change in solubility. Therefore, as schematically shown in FIG. 14, the maximum temperature difference (maximum allowable temperature difference) between the rinsing liquid and the liquid film F that allows the range of change in solubility to fall within the allowable range becomes smaller as the pH value difference between the rinse liquid and the liquid film F becomes larger. For example, when sulfuric acid with a pH value of approximately "1" is used as the treatment liquid, and carbonated water, which is a weakly acidic liquid with a pH value of approximately "5", is used as the rinse liquid, the maximum allowable temperature difference is approximately "200". becomes. In other words, when carbonated water is used as the rinsing liquid, it is heated so that the temperature difference between it and the liquid film F is "200" or less (for example, the liquid film F after the plasma treatment is heated to 250° C. If the temperature is elevated to a level of 50° C. or higher, preferably 80° C. or higher, the range of change in solubility caused by contact with the rinse liquid can be kept within an allowable range.

<2-2. Processing unit>
The configuration of the processing unit 132a capable of executing the rinse process based on the above concept will be described with reference to FIG. FIG. 15 is a side view schematically showing the configuration of the processing unit 132a. This processing unit 132a is provided in the substrate processing system 100, for example, like the processing unit 132 according to the first embodiment.

The processing unit 132a differs from the processing unit 132 in the configuration of the liquid supply section, and the other configurations (the holding section 1, the plasma generation section 3, the guard section 4, and the chamber 5) are the same as those of the processing unit 132. It is the same. In the following, elements that are not different from the processing unit 132 are denoted by the same reference numerals, and descriptions thereof are omitted.

The liquid supply section 2a provided in the processing unit 132a according to this embodiment is an element that supplies the liquid to the substrate W held in the holding section 1, like the liquid supply section 2 provided in the processing unit 132 according to the first embodiment. is. The liquid supply unit 2a includes, for example, three nozzles (a sulfuric acid nozzle 21a, a pure water nozzle 21b, and a carbonated water nozzle 21c) and a nozzle moving mechanism 22.

As described in the first embodiment, the sulfuric acid nozzle 21a is a nozzle that discharges sulfuric acid toward the substrate W held by the holder 1, and the pure water nozzle 21b is held by the holder 1. It is a nozzle for discharging pure water toward the substrate W. FIG. As described in the first embodiment, the sulfuric acid nozzle 21a is connected to the sulfuric acid supply unit 20a for supplying sulfuric acid thereto, and the pure water nozzle 21b is connected to the pure water supply unit 20b for supplying pure water thereto. Connected.

The carbonated water nozzle 21c is a nozzle that ejects heated carbonated water ( _CO2 water) toward the substrate W held in the holding unit 1. Specifically, for example, the ejection port 210c is formed on one end face. It is a formed straight nozzle. The carbonated water nozzle 21c is connected to a carbonated water supply unit 20c for supplying carbonated water thereto. Specifically, the carbonated water supply unit 20c includes, for example, a supply pipe 201c one end of which is connected to the carbonated water nozzle 21c, and a carbonated water supply source 202c connected to the other end of the supply pipe 201c. The carbonated water supply source 202c includes, for example, a pure water tank that stores pure water (eg, DIW), a dissolution processing unit that dissolves carbon dioxide in the pure water stored therein to generate carbonated water, and the like. consists of Further, a valve 203c, a flow rate adjusting section 204c, and a heating section 205c are inserted in the supply pipe 201c. The valve 203c is a valve that switches between supplying and stopping carbonated water through the supply pipe 201c, and is controlled by the control unit 140. FIG. The flow rate adjusting unit 204c is composed of, for example, a mass flow controller, and under the control of the control unit 140, adjusts the flow rate of carbonated water flowing through the supply pipe 201c. The heating unit 205c is configured by, for example, a heater, and heats the carbonated water flowing through the supply pipe 201c to a temperature instructed by the control unit 140 under the control of the control unit 140 . In such a configuration, when the valve 203c is opened, carbonated water at a predetermined flow rate adjusted by the flow rate adjusting unit 204c flows from the carbonated water supply source 202c through the supply pipe 201c, and heated to a predetermined temperature by the heating unit 205c. is supplied to the carbonated water nozzle 21c and discharged from the discharge port 210c. That is, heated carbonated water (hereinafter referred to as "heated carbonated water") is discharged from the carbonated water nozzle 21c.

The configuration of the nozzle moving mechanism 22 is as described in the first embodiment. However, in this embodiment, the nozzle unit U is configured by connecting the sulfuric acid nozzle 21a, the pure water nozzle 21b, and the carbonated water nozzle 21c via a connecting member or the like. By moving the nozzle unit U along an arc-shaped trajectory, the nozzles 21a, 21b, and 21c are moved between their respective nozzle processing positions and nozzle standby positions. Needless to say, the "nozzle processing position" of the carbonated water nozzle 21c is such that the liquid discharged from the discharge port 210c of the nozzle 21c is held in the holder 1, similarly to the nozzle processing positions of the other nozzles 21a and 21b. Specifically, for example, above the main surface and facing the center of the main surface in the vertical direction. position.

<2-3. Process Flow>
Next, the flow of processing related to the rinsing process performed in the processing unit 132a will be described with continued reference to FIG. The overall flow of a series of processes performed on the substrate W is the same as in the first embodiment (see FIG. 5).

First, heated carbonated water as a rinsing liquid is supplied to the substrate W after plasma processing (that is, resist stripping processing) has been completed, so that the substrate W is brought into contact with the rinsing liquid. Specifically, for example, the nozzle moving mechanism 22 moves the carbonated water nozzle 21c from the nozzle waiting position to the nozzle processing position. When the carbonated water nozzle 21c is placed at the nozzle processing position, the valve 203c provided on the supply pipe 201c is opened. Then, as described above, the carbonated water stored in the carbonated water supply source 202c flows through the supply pipe 201c at a predetermined flow rate adjusted by the flow rate adjusting unit 204c, and heated to a predetermined temperature (here, , a temperature of 80° C. or more and 100° C. or less), supplied to the carbonated water nozzle 21c, and discharged from the discharge port 210c. The heated carbonated water discharged from the carbonated water nozzle 21c arranged at the processing position reaches a predetermined position (for example, the center of the main surface) on the upper main surface of the substrate W held by the holding unit 1. liquid. As a result, heated carbonated water as a rinsing liquid is supplied to (contacts with) the substrate W. As shown in FIG.

As described above, when sulfuric acid with a pH value of approximately "1" is used as the treatment liquid and carbonated water, which is a weakly acidic liquid with a pH value of approximately "5", is used as the rinse liquid, the liquid film F By heating so that the temperature difference between the two is "200" or less, it is possible to keep the range of change in solubility caused by contact with the rinse liquid within an allowable range. In this rinsing step, the carbonated water stored in the carbonated water supply source 202c is heated to a temperature of 80° C. or more and 100° C. or less and used as the rinse liquid. Even if the temperature is raised to about 250° C., it is possible to keep the range of change in solubility caused by contact with the rinsing liquid within an allowable range in which the resist is not precipitated.

Also in this embodiment, as in the first embodiment, when the carbonated water nozzle 21c starts discharging heated carbonated water as a rinsing liquid, the rotation mechanism 13 rotates the substrate held by the holding unit 1. W is rotated while increasing its number of revolutions step by step. Specifically, for example, the rotation mechanism 13 gradually increases the rotation speed of the substrate W from a sufficiently low first rotation speed R1 to a higher second rotation speed R2 over the first time T1. It is enlarged (see FIG. 12). When the rotation speed reaches the second rotation speed R2, the rotation mechanism 13 continues to rotate the substrate W at the second rotation speed R2.

As the substrate W is rotated, the heated carbonated water as the rinsing liquid discharged from the carbonated water nozzle 21c and deposited on the upper main surface of the substrate W is rapidly moved toward the peripheral edge of the substrate W by centrifugal force. spread out. On the other hand, the sulfuric acid liquid film F covering substantially the entire main surface of the substrate W (that is, the sulfuric acid liquid film F in which the stripped resist is dissolved) is removed by the newly supplied heated carbonated water as the rinsing liquid. It is swept outward and discharged to the surroundings of the substrate W quickly. That is, the sulfuric acid liquid film F covering the substrate W when the plasma processing is completed is replaced by the heated carbonated water as the rinsing liquid. Further, by increasing the rotational speed stepwise, the liquid film F on the substrate W can be replaced with the heated carbonated water as the rinsing liquid without lowering the cleanliness of the substrate W. FIG.

After a predetermined period of time has elapsed since the carbonated water nozzle 21c started discharging the heated carbonated water as the rinse liquid, the valve 203c is closed to stop discharging the heated carbonated water. As a result, the rinsing process is finished, and the sulfuric acid liquid film F covering the substrate W at the time when the plasma processing is finished is washed away with the heated carbonated water as the rinsing liquid.

A second rinse process similar to that of the first embodiment may be performed on the substrate W after the above rinse process is completed. That is, the above rinsing step may be the first rinsing step (that is, the heated carbonated water is the first rinsing liquid), and then the second rinsing step of supplying pure water as the second rinsing liquid may be performed.

<2-4. Effect>
In the above-described embodiment, by using, as the rinsing liquid, a liquid whose temperature difference with respect to the liquid film F is equal to or less than the maximum allowable temperature difference, the width of change in solubility is kept within the allowable range. According to this configuration, it is possible to use various liquids as the rinse liquid by adjusting the temperature, so that the range of choices for the rinse liquid can be expanded.

More specifically, in the above embodiment, the rinse liquid is carbonated water heated to a temperature of 80°C or higher and 100°C or lower. With such a rinsing liquid, even if the rinsing liquid comes into contact with (is supplied to) the liquid film F whose temperature has been raised by being irradiated with plasma, the width of temperature change can be kept sufficiently small. Therefore, it is possible to sufficiently reduce the width of change in solubility when the rinse liquid is brought into contact with the liquid, thereby sufficiently suppressing the generation of particles.

<3. Third Embodiment>
For example, in the first embodiment, sulfuric acid as a rinsing liquid (first rinsing liquid) is discharged from the sulfuric acid nozzle 21a onto the substrate W held by the holding unit 1 to supply the rinsing liquid to the substrate W. Thus, the substrate W is brought into contact with the rinse liquid, but the manner in which the substrate W is brought into contact with the rinse liquid is not limited to this. For example, the rinse liquid may be brought into contact with the substrate W by immersing the substrate W in a storage tank in which the rinse liquid is stored.

<3-1. Immersion unit>
The configuration of the immersion unit 7 for realizing such a processing mode will be described with reference to FIG. 16 . FIG. 16 is a side view schematically showing the configuration of the immersion unit 7. As shown in FIG. The immersion unit 7 is a processing unit that performs a rinsing process on one or a plurality of substrates W at once. work to perform a series of processes on the substrate W. Specifically, for example, when the processing unit 132 (FIG. 3) described in the first embodiment is provided as at least one of the plurality of processing units included in the main body 130 of the substrate processing system 100, the remaining As at least one of the treatment units, an immersion unit 7 is provided.

The immersion unit 7 includes a storage tank 71 , a liquid supply section 72 and a holding section 73 .

The storage tank 71 is a tank that stores liquid. Specifically, the storage tank 71 has, for example, an internal volume capable of accommodating one or more substrates W in an upright posture, and the upper end side is open. The bottom side of the storage tank 71 is closed, and a drain pipe 712 with a valve 711 inserted therein is connected. A valve 711 is a valve that switches between draining liquid through a liquid draining pipe 712 and stopping, and is controlled by the control unit 140 . That is, when the valve 711 is opened under the control of the controller 140 , the liquid stored in the storage tank 71 is drained through the drain pipe 712 . An outer tank 713 is provided in the vicinity of the upper end of the outer peripheral wall of the storage tank 71 . The upper edge of the outer tank 713 is located above the upper edge of the reservoir tank 71, and the liquid overflowing from the upper edge of the reservoir tank 71 is received by the outer tank 713 and discharged through a drain pipe (not shown). drained through the

The liquid supply unit 72 is an element that supplies liquid to the storage tank 71 (and thus to the substrate W arranged inside the storage tank 71). 721b).

The sulfuric acid nozzle 721a is a nozzle for discharging sulfuric acid. The sulfuric acid nozzle 721a is connected to a sulfuric acid supply unit 70a for supplying sulfuric acid thereto. The structure of the sulfuric acid supply section 70a is the same as that of the sulfuric acid supply section 20a described above. Specifically, the sulfuric acid supply unit 70a is, for example, a supply pipe 701a having one end connected to a sulfuric acid nozzle 721a, a sulfuric acid supply source 702a connected to the other end of the supply pipe 701a, and inserted into the supply pipe 701a. It includes a valve 703a, a flow rate adjusting section 704a, and the like. The sulfuric acid supply source 702a stores, for example, sulfuric acid of the same concentration as that stored in the sulfuric acid supply source 202a (that is, the sulfuric acid supply source 202a provided in the processing unit 132 used in cooperation with the soaking unit 7). be. In such a configuration, when the valve 703a is opened under the control of the control unit 140, a predetermined flow rate of sulfuric acid adjusted by the flow rate adjustment unit 704a is supplied from the sulfuric acid supply source 702a to the sulfuric acid nozzle 721a through the supply pipe 701a. and is discharged from here and supplied into the storage tank 71 .

The pure water nozzle 721b is a nozzle for discharging pure water. A pure water supply unit 70b for supplying pure water to the pure water nozzle 721b is connected to the pure water nozzle 721b. The configuration of the pure water supply section 70b is the same as that of the pure water supply section 20b described above. That is, the pure water supply unit 70b specifically includes, for example, a supply pipe 701b having one end connected to the pure water nozzle 721b, a pure water supply source 702b connected to the other end of the supply pipe 701b, and the supply pipe 701b. It includes an inserted valve 703b and a flow rate adjusting section 704b. In such a configuration, when the valve 703b is opened under the control of the control unit 140, pure water at a predetermined flow rate adjusted by the flow rate adjustment unit 704b is supplied from the pure water supply source 702b through the supply pipe 701b to the pure water nozzle. 721 b , discharged from here, and supplied into the storage tank 71 .

The holding part 73 holds one or more substrates W in an upright posture such that the main surfaces thereof are arranged in a substantially vertical plane. Specifically, the holding portion 73 has, for example, a configuration in which a plurality of holding rods 732 protrude from a main surface of a body plate 731 which is provided in an upright posture such that the main surface is arranged in a vertical plane. A plurality of holding rods 732 abut against the peripheral portion of the substrate W from below, thereby holding the substrate W in an upright posture. When a plurality of substrates W are held, the plurality of substrates W are arranged at intervals along the extending direction of the holding bar 732 .

A holding portion moving mechanism 733 is connected to the holding portion 73 . The holding portion moving mechanism 733 moves the holding portion 73 to a position (immersion position) where the substrate W held therein is placed inside the storage tank 71 (immersion position) and a position (immersion position) where the held substrate W is placed outside the storage tank 71 ( For example, it is a mechanism for moving up and down between a position (delivery position) arranged above the storage tank 71 .

<3-2. Process Flow>
The flow of processing related to the rinsing process performed in the immersion unit 7 will be described with reference to FIG. 17 in addition to FIG. FIG. 17 is a diagram showing the flow of the processing.

Step S<b>101 : Storage Step First, sulfuric acid is stored in the storage tank 71 as the first rinse liquid. Specifically, for example, the valve 703a provided in the supply pipe 701a is opened. Then, the sulfuric acid stored in the sulfuric acid supply source 702a is supplied to the sulfuric acid nozzle 721a through the supply pipe 701a at a predetermined flow rate adjusted by the flow rate adjusting section 704a, and is discharged therefrom. The discharged sulfuric acid is supplied to the storage tank 71 and stored therein.

Step S<b>102 : Loading Step On the other hand, the substrate W to be rinsed is loaded into the immersion unit 7 . That is, in the processing unit 132, when a series of processes from step S1 to step S6 is completed, the main transfer robot 131 moves the substrate W held by the holding unit 1 (that is, the substrate after plasma processing is completed). W) is carried out and carried into the immersion unit 7 . At this time, the main transport robot 131 transports the substrate W in a horizontal posture and carries it into the immersion unit 7 so that the liquid film F held on the substrate W is maintained.

Step S103: First Rinse Step Subsequently, the substrate W is immersed in the storage tank 71 in which sulfuric acid as the first rinse liquid is stored. Specifically, for example, first, the substrate W carried into the immersion unit 7 is changed from the horizontal posture to the standing posture, and then held by the holding portion 73 arranged at the delivery position above the storage tank 71 . be done. A plurality of substrates W may be held by the holding portion 73 . When one or more substrates W are held by the holding portion 73, the holding portion moving mechanism 733 moves (lowers) the holding portion 73 from the delivery position to the immersion position. In a state where sulfuric acid as the first rinse liquid is stored in the storage tank 71, the holding section 73 is arranged at the immersion position, so that the substrate W held therein is exposed to the sulfuric acid as the first rinse liquid. The substrate W is immersed, and the substrate W is brought into contact with the first rinse liquid.

At the stage where the substrate W is in the upright position, part of the liquid film F held here falls along the main surface of the substrate W and is discharged, but the remaining part still remains on the substrate W. remains on the main surface of The substrate W in such a state is immersed in the storage tank 71 in which sulfuric acid as the first rinse liquid is stored. The sulfuric acid liquid film F remaining on the main surface of the (that is, the sulfuric acid liquid film F in which the stripped resist is dissolved) is removed by sulfuric acid as the first rinse liquid (that is, clean sulfuric acid that does not dissolve the resist). , is replaced.

In the first rinsing step, the sulfuric acid stored in the sulfuric acid supply source 702a is used as the first rinsing liquid. is stored. That is, in the liquid film forming step (step S2), the liquid supplied to the substrate W as the processing liquid when forming the liquid film F, and the liquid supplied to the substrate W as the first rinse liquid in the first rinsing step. are both sulfuric acid and have the same concentration. Needless to say, in this case, the difference in pH value between the first rinse liquid and the liquid film F is such that the first rinse liquid is supplied to the heated liquid film F without being heated and brought into contact with the liquid film F. It is well below the maximum allowable pH difference of "2" and is almost zero. Therefore, when the first rinse liquid contacts the liquid film F, the pH value hardly changes. Therefore, the width of change in solubility caused by contact with the first rinse liquid is sufficiently small, and deposition of the resist is sufficiently avoided.

Step S104: Second Rinsing Step After a predetermined time has passed since the substrate W was immersed in sulfuric acid as the first rinse liquid, the liquid in the storage tank 71 is changed from the sulfuric acid as the first rinse liquid to the second rinse liquid. It is replaced with pure water as a liquid. Specifically, for example, the valve 711 provided in the drain pipe 712 is opened. As a result, the sulfuric acid as the first rinse liquid stored in the storage tank 71 is drained. Meanwhile, the valve 703b provided in the supply pipe 701b is opened. Then, the pure water stored in the pure water supply source 702b is supplied through the supply pipe 701b to the pure water nozzle 721b at a predetermined flow rate adjusted by the flow rate adjusting section 704b, and is discharged therefrom. The discharged pure water is supplied to the storage tank 71 and stored therein. By replacing the liquid in the storage tank 71 from sulfuric acid as the first rinse liquid with pure water as the second rinse liquid, the substrate W held by the holding portion 73 arranged at the immersion position is The substrate W is immersed in pure water as the second rinse liquid, and the second rinse liquid is brought into contact with the substrate W. As shown in FIG. That is, the pure water as the second rinse liquid is brought into contact with the substrate W, and the sulfuric acid as the first rinse liquid remaining on the main surface of the substrate W is replaced by the pure water as the second rinse liquid. go.

Thus, in the second rinse step, the pure water stored in the pure water supply source 702b is used as the second rinse liquid. That is, the pH value of the second rinse is significantly different from the pH value of the sulfuric acid supplied to the substrate W as the first rinse. Therefore, the contact (supply) of the pure water as the second rinse liquid dilutes the sulfuric acid as the first rinse liquid remaining on the substrate W, resulting in a large change (increase) in the pH value. do. However, since the first rinse liquid remaining on the substrate W at this time is clean sulfuric acid in which the resist does not dissolve, the resist does not deposit even if the pH value changes significantly.

After a predetermined time has elapsed since the substrate W was immersed in the pure water as the second rinse liquid, the holding portion moving mechanism 733 moves (raises) the holding portion 73 from the immersion position to the delivery position.

The rinse process is completed by the above. After that, the substrate W held by the holding part 73 is unloaded from the dipping unit 7 by the main transfer robot 131, for example.

<3-3. State of substrate after treatment>
In FIG. 18, sulfuric acid having the same concentration as the processing liquid for forming the liquid film F is used as the rinsing liquid (first rinsing liquid) that is first brought into contact with the substrate W after the resist stripping process. A microscopic image of the upper surface of the substrate W after the treatment (after the above series of treatments (steps S1 to S8) is performed) when the rinse treatment (steps S101 to S104) according to the aspect of (1) is performed. It is shown. As is clear from this microscope image, as the rinse liquid first brought into contact with the substrate W after the resist stripping process, sulfuric acid having the same concentration as the treatment liquid is used, and this rinse liquid is the same as the rinse liquid. It can be seen that no particles exist on the substrate W after processing even when the substrate W is brought into contact (supplied) with the liquid by immersing the substrate W in the storage tank 71 storing the liquid. Needless to say, the reason why particles are not generated on the processed substrate W is that the pH value hardly changes when the rinse liquid contacts the liquid film F. This is probably because the solubility of the resist did not decrease and the resist did not precipitate.

<3-4. Effect>
According to the above embodiment, in the rinsing step, the substrate W is immersed in the reservoir 71 in which the rinsing liquid (first rinsing liquid) is stored. According to this configuration, the liquid film F in which the stripped resist is dissolved can be quickly discharged from the substrate W and replaced with the rinse liquid.

<4. Other Embodiments>
In the first rinsing process according to the first embodiment, the first rinsing liquid (specifically, for example, sulfuric acid having the same concentration as the processing liquid) may be brought into contact with the substrate W after being heated. For this purpose, for example, like the processing unit 132b shown in FIG. A heated sulfuric acid nozzle 21d for discharging sulfuric acid may be provided. The heated sulfuric acid nozzle 21d is connected to the other end of a supply pipe 201d, one end of which is connected to the sulfuric acid supply source 202a. Also, a valve 203d, a flow rate adjusting section 204d, and a heating section 205d are inserted in the supply pipe 201d. In such a configuration, when the valve 203d is opened under the control of the control unit 140, sulfuric acid at a predetermined flow rate adjusted by the flow rate adjustment unit 204d flows from the sulfuric acid supply source 202a through the supply pipe 201d, and the heating unit After being heated to a predetermined temperature by 205d, it is supplied to the heated sulfuric acid nozzle 21d and discharged therefrom. That is, in the first rinsing step (step S71), sulfuric acid as the first rinsing liquid (that is, sulfuric acid having the same concentration as the processing liquid) can be heated and brought into contact with the substrate W. FIG.

According to this modification, the rinse liquid (first rinse liquid) is heated and then brought into contact with the substrate W. Therefore, the first rinse liquid is brought into contact with the liquid film F whose temperature is raised by being irradiated with the plasma. supply), the width of temperature change can be kept sufficiently small. In other words, both the width of change in pH and the width of change in temperature can be kept small. Therefore, the width of change in solubility when the first rinse liquid is brought into contact with the liquid can be made particularly small, and the generation of particles can be particularly sufficiently suppressed.

Also, in the first embodiment, what kind of rinse liquid (first rinse liquid) is the type of liquid if the difference in pH value between the liquid film F and the liquid film F is equal to or less than the maximum allowable pH difference? and is not limited to the sulfuric acid exemplified above. For example, the rinse liquid may be hydrochloric acid (eg, dilute hydrochloric acid with a pH value of "3"). Needless to say, no matter what kind of liquid is used, the difference in pH value between the liquid film F and the liquid film F should be less than the maximum allowable pH difference defined from the given treatment conditions. , the concentration may be adjusted as necessary.

Further, in the first embodiment, the rinse liquid is sulfuric acid having the same concentration as the processing liquid used for the substrate W as the processing liquid when forming the liquid film F, but the rinse liquid has a concentration different from that of the processing liquid. It may be different sulfuric acid. Needless to say, even in this case, the rinsing liquid has a concentration such that the difference in pH value between the liquid film F and the liquid film F is equal to or less than the maximum allowable pH difference defined by the given processing conditions. be.

In the second embodiment, any type of rinse liquid may be used as long as the temperature difference between the liquid film F and the liquid film F is equal to or less than the maximum allowable temperature difference. It is not limited to the exemplified carbonated water. For example, heated pure water, sulfuric acid, hydrochloric acid, or the like may be used as the rinse liquid. Needless to say, no matter what kind of liquid is used, the temperature difference between the liquid film F and the liquid film F is set to be equal to or less than the maximum allowable temperature difference defined by the given processing conditions. The heating temperature may be set as necessary. For example, if a liquid with a lower pH value than carbonated water (i.e., a liquid with a smaller pH value difference with the liquid film F) is used as the rinse liquid, the maximum allowable temperature difference is greater than "200". there is a possibility. That is, there is a possibility that the heating temperature can be lower than 80°C. Conversely, if a liquid having a higher pH value than carbonated water (for example, pure water) is used as the rinse liquid, the maximum allowable temperature difference may be smaller than "200". That is, there is a possibility that the heating temperature will need to be higher than 80°C.

In the third embodiment, the first rinse liquid stored in the storage tank 71 may be the rinse liquid (that is, heated carbonated water) according to the second embodiment. Further, in the third embodiment, the step of immersing the substrate W in the storage tank 71 in which pure water is stored as the second rinsing liquid (second rinsing step) was performed. You don't have to do it with For example, after the first rinsing process is completed, the substrate W is unloaded from the immersion unit 7 and loaded into the processing unit 132 again, where the second rinsing process (that is, the second rinsing process according to the first embodiment ( Step S72)) may be performed.

The configuration of the processing unit 132 and the flow of processing performed here are not limited to those exemplified in the above embodiments.

For example, in the above-described embodiment, the nozzles 21a, 21b, and 21c (or the nozzles 721a and 721b) for ejecting different types of liquids are separately provided. You may make it discharge alternatively. In this case, a plurality of supply pipes 201a, 201b, 201c (or a plurality of supply pipes 701a, 701b) may be connected to the single nozzle.

In the above embodiment, the nozzle moving mechanism 22 integrally moves the plurality of nozzles 21a, 21b, and 21c. Each nozzle 21a, 21b, 21c may be moved independently. Needless to say, in this case, it is not necessary to connect the plurality of nozzles 21a, 21b, 21c. Also, at least one of the plurality of nozzles 21a, 21b, 21c may be fixedly provided. That is, the nozzle moving mechanism may be omitted for at least one nozzle.

In the above-described embodiment, the holding unit 1 holds the substrate W in a horizontal posture by gripping the peripheral edge of the substrate W with the chuck pins 12, but the method for holding the substrate W is limited to this. It does not have to be something that can be used, but it can be anything. For example, the holding section may hold the substrate W in a horizontal posture by sucking the rear surface of the substrate W with a suction mechanism provided on the upper surface of the base section 11 .

Also, in the above embodiment, a plurality of guards 41 may be provided. In this case, the plurality of guards 41 may have basically the same configuration but different sizes, and the plurality of guards 41 having different sizes may be nested. In other words, the cylindrical portion 41a may be arranged concentrically, and the inclined portion 41b and the extending portion 41c may be arranged in a nested manner so as to overlap each other. When a plurality of guards 41 are provided, the guard moving mechanism 42 moves each guard 41 independently and switches the position of each guard 41 according to the type of liquid to be discharged onto the substrate W. , the guard 41 for receiving the scattered liquid may be switched.

Further, in each of the above embodiments, the plasma generating section 3 generates plasma under atmospheric pressure, but it may generate plasma under low pressure. That is, a pump is provided for depressurizing the inner space of the chamber 5, and in a state in which the inner space of the chamber 5 is depressurized to a predetermined pressure by the pump, a voltage is applied to the plasma reactor 31 to generate plasma. good too.

Further, in the above embodiment, the processing unit 132 performs the processing of removing the resist formed on the substrate W, but the processing performed in the processing unit 132 is not limited to this. For example, the processing unit 132 may perform processing for removing organic substances (eg, organic particles, organic layers, organic films) existing on the substrate W. FIG.

Further, in the above embodiment, sulfuric acid is used as the processing liquid, but the processing liquid is not limited to this. For example, a chemical liquid containing at least one of sulfuric acid, sulfate, peroxosulfate, and peroxosulfate may be used as the treatment liquid. Also, a chemical solution containing hydrogen peroxide may be used as the treatment liquid, for example, a mixture of sulfuric acid and hydrogen peroxide solution may be used as the treatment liquid. Furthermore, depending on the purpose of the plasma treatment, the type of object to be removed, etc., chemical solutions such as SC1 (mixed solution of hydrogen peroxide solution and ammonia), SC2 (mixed solution of hydrogen peroxide solution and hydrochloric acid) (so-called A cleaning chemical) may be used as the processing liquid, or a chemical such as hydrofluoric acid, hydrochloric acid, or phosphoric acid (so-called etching chemical) may be used as the processing liquid.

The configuration of the substrate processing system 100 and the flow of processing performed here are not limited to those illustrated in the above embodiments.

For example, the number of processing units 132 provided in the substrate processing system 100 need not be twelve. Further, for example, the number of load ports 111 provided in the substrate processing system 100 may not be three.

Moreover, the program P may be stored in a recording medium, and the program P may be installed in the control unit 140 using this recording medium.

Further, the substrate W to be processed in the substrate processing system 100 may not necessarily be a semiconductor substrate. For example, substrates W to be processed include photomask glass substrates, liquid crystal display glass substrates, plasma display glass substrates, FED (Field Emission Display) substrates, optical disk substrates, magnetic disk substrates, and magneto-optical disk substrates. substrate, etc. Also, the shape and size of the substrate W to be processed are not limited to those illustrated above. For example, the shape of the substrate W to be processed may be a rectangular plate shape.

As described above, the substrate processing apparatus and substrate processing method have been described in detail, but the above description is illustrative in all aspects, and the substrate processing apparatus and substrate processing method are not limited to this. It is understood that numerous variations not illustrated can be envisioned without departing from the scope of this disclosure. Each configuration described in each of the above embodiments and each of the above modifications can be appropriately combined or omitted as long as they do not contradict each other.

REFERENCE SIGNS LIST 1 holding part 2 liquid supply part 21a sulfuric acid nozzle 21b pure water nozzle 21c carbonated water nozzle 20a sulfuric acid supply part 20b pure water supply part 20c carbonated water supply part 205c heating part 3 plasma generation part 4 guard part 5 chamber 7 immersion unit 132 substrate processing Equipment (processing unit)
100 substrate processing system

Claims (11)

a liquid film forming step of supplying an acidic processing liquid to the substrate provided with the resist to form a liquid film of the processing liquid;
a plasma processing step of irradiating the substrate holding the liquid film with plasma to proceed with the resist stripping process;
a rinsing step of contacting the substrate after the stripping process with a rinsing liquid such that the change in the solubility of the resist dissolved in the liquid film is within an allowable range for preventing deposition of the resist;
A substrate processing method comprising: The substrate processing method according to claim 1,
As the rinsing liquid, an acidic liquid having a pH value difference between the liquid film and the liquid film that is equal to or less than the maximum allowable pH difference is used to keep the range of change in the solubility within the allowable range.
Substrate processing method. The substrate processing method according to claim 2,
The rinse liquid is a liquid having a pH value difference of 2 or less with respect to the liquid film.
Substrate processing method. The substrate processing method according to claim 2 or 3,
Both the rinse solution and the treatment solution are sulfuric acid,
Substrate processing method. The substrate processing method according to claim 4,
The rinsing liquid and the treatment liquid are sulfuric acid having the same concentration,
Substrate processing method. The substrate processing method according to any one of claims 2 to 5,
The rinse liquid is heated and brought into contact with the substrate;
Substrate processing method. The substrate processing method according to claim 1,
As the rinsing liquid, a liquid whose temperature difference with the liquid film is equal to or less than the maximum allowable temperature difference is used, so that the width of change in the solubility is kept within the allowable range.
Substrate processing method. The substrate processing method according to claim 7,
The rinse liquid is carbonated water heated to a temperature of 80° C. or more and 100° C. or less.
Substrate processing method. The substrate processing method according to any one of claims 1 to 8,
In the rinsing step,
While discharging the rinse liquid from the nozzle toward the substrate, the substrate is rotated while increasing the number of revolutions stepwise.
Substrate processing method. The substrate processing method according to any one of claims 1 to 8,
In the rinsing step,
immersing the substrate in a reservoir containing the rinse liquid;
Substrate processing method. a holding part that holds the substrate;
a liquid supply unit that supplies liquid to the substrate held by the holding unit;
a plasma irradiation unit that irradiates the substrate held by the holding unit with plasma;
a control unit that controls the holding unit, the liquid supply unit, and the plasma irradiation unit;
with
The control unit
causing the holding part to hold a substrate provided with a resist;
causing the liquid supply unit to supply an acidic processing liquid to the substrate to form a liquid film of the processing liquid;
causing the plasma irradiation unit to irradiate the substrate holding the liquid film with plasma to proceed with the resist stripping process;
The liquid supply unit is caused to supply the rinse liquid to the substrate on which the stripping process is completed, such that the range of change in solubility of the resist dissolved in the liquid film is within an allowable range for preventing deposition of the resist. ,
Substrate processing equipment.

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