Substrate processing method and substrate processing apparatus

Abstract

To provide a substrate processing method and substrate processor, capable of suppressing environmental load while well etching a substrate.SOLUTION: A substrate processing method includes preparation of a substrate with a top face in which a first oxide layer exposes (substrate preparation process). By forming a first polymer film containing acid polymer on the top face of the substrate, the substrate is etched (first etching process). After the first etching process, a first rinse liquid for cleaning the top face of the substrate is supplied to the top face of the substrate (first rinse process).SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a substrate processing method for processing a substrate and a substrate processing apparatus for processing a substrate. Examples of substrates to be processed include semiconductor wafers, substrates for flat panel displays (FPDs) such as liquid crystal display devices and organic electroluminescence (EL) display devices, substrates for optical discs, substrates for magnetic discs, substrates for magneto-optical discs, substrates for photomasks, ceramic substrates, substrates for solar cells, and the like.

Background Art

[0002] In Patent Document 1 below, a step of forming an oxide metal layer by supplying an oxidizing fluid such as hydrogen peroxide water (H 2 O 2 water) to a substrate and a step of removing the oxide metal layer by supplying an etching solution such as diluted hydrofluoric acid (DHF) to the substrate are repeated to achieve a desired etching amount.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the substrate processing of Patent Document 1, the oxide metal layer is etched by repeating the formation and removal of the oxide metal layer. However, in the substrate processing of Patent Document 1, in the formation and removal of the oxide metal layer, processing with a continuous flow of diluted hydrofluoric acid and hydrogen peroxide water is respectively adopted. Therefore, in substrate processing, it is necessary to use a large amount of chemical solutions such as diluted hydrofluoric acid and hydrogen peroxide water, and thus the environmental load becomes a problem.

[0005] Therefore, one object of the present invention is to provide a substrate processing method and a substrate processing apparatus that can reduce the environmental load while etching the substrate well.

Means for Solving the Problems

[0006] One embodiment of the present invention includes a substrate preparation step of preparing a substrate having a main surface on which a first oxide layer is exposed, a first etching step of forming a first polymer film containing a first acidic polymer on the main surface of the substrate to etch the substrate, and a first rinsing step of supplying a first rinsing liquid for cleaning the main surface of the substrate to the main surface of the substrate after the first etching step. A substrate processing method is provided.

[0007] According to this substrate processing method, since a first polymer film is formed on the main surface of the substrate and the substrate is etched, the first oxide layer is removed from the substrate. Thereafter, since the main surface of the substrate is cleaned with the first rinsing liquid, the first polymer film is removed from the main surface of the substrate. Therefore, etching of the substrate can be started by forming the first polymer film, and the etching of the substrate can be stopped by removing the first polymer film from the main surface of the substrate. Therefore, since the etching amount of the substrate can be adjusted by forming and removing the first polymer film, the substrate can be etched well.

[0008] Since the first polymer film used for etching the substrate contains a first acidic polymer, it is in a semi-solid or solid state. Therefore, the first polymer film is more likely to remain on the main surface of the substrate than a liquid. Therefore, it is not necessary to continuously supply the first acidic polymer to the main surface of the substrate throughout the entire period while etching the substrate. In other words, at least after forming the first polymer film, it is not necessary to additionally supply the first acidic polymer to the upper surface of the substrate. Therefore, the environmental load can be reduced.

[0009] In one embodiment of the present invention, the first polymer film further contains a first alkaline component. And the first etching step includes a first etching start step of starting the etching of the substrate by heating the first polymer film after the first polymer film is formed to evaporate the first alkaline component from the first polymer film. According to this configuration, together with the acidic polymer No. 1 the alkaline component is contained in the first polymer film. Therefore, until the first polymer film is heated after the first polymer film is formed, the acidic polymer is neutralized by the first alkaline component and is almost deactivated. Therefore, until the first polymer film is heated after the first polymer film is formed, the etching of the substrate hardly starts. By heating the first polymer film to evaporate the first alkaline component, the first acidic polymer in the first polymer film regains its activity and the etching of the substrate starts. Therefore, the substrate can be etched accurately. In particular, the start timing of the etching of the substrate can be accurately controlled.

[0010] In one embodiment of the present invention, the first polymer film further contains a first conductive polymer. Therefore, by the action of the conductive polymer, the ionization of the acidic polymer in the polymer film can be promoted. Therefore, the acidic polymer can act effectively on the oxide layer. That is, the first conductive polymer functions as a medium for the first acidic polymer to release protons (hydrogen ions). Therefore, even when the liquid components such as the solvent have completely disappeared from the first polymer film as long as the conductive polymer is contained in the first polymer film, the first acidic polymer can be ionized and the ionized first acidic polymer can act on the oxide layer.

[0011] In one embodiment of the present invention, the first etching step includes a first oxide layer removing step of removing at least a part of the first oxide layer by the acidic polymer in the first polymer film. The first rinsing step includes a first polymer film removing step of removing the first polymer film from the main surface of the substrate by the first rinsing liquid. According to this substrate processing method, at least a part of the first oxide layer exposed from the main surface of the substrate is removed by the first acidic polymer contained in the first polymer film. Then, the first polymer film can be removed from the main surface of the substrate by the first rinsing liquid. Therefore, the substrate can be etched better by forming and removing the first polymer film.

[0012] In one embodiment of the present invention, after the first rinsing step, the first etching step and the first rinsing step are further executed at least once each in this order. According to this substrate processing method, after the first rinsing step, the first etching step and the first rinsing step are further executed at least once each in this order. That is, the formation and removal of the first polymer film are executed multiple times. Even when the substrate is not sufficiently etched by one formation and removal of the first polymer film, the substrate can be sufficiently etched by executing the formation and removal of the first polymer film multiple times. In particular, even when the first oxide layer is not etched by a desired amount by one formation and removal of the first polymer film, the first oxide layer can be sufficiently etched by executing the formation and removal of the first polymer film multiple times. For example, the first oxide layer may be completely removed from the substrate by forming and removing the first polymer film multiple times.

[0013] Furthermore, when the formation and removal of the first polymer film are performed multiple times, the first etching step is performed again after the first rinsing step. Therefore, after the first polymer film formed on the main surface of the substrate is once removed, the first polymer film is formed again on the main surface of the substrate. Therefore, the first polymer film in which the first acidic polymer has been consumed by etching the substrate can be removed from the main surface of the substrate, and the substrate can be etched with a new first polymer film. Accordingly, compared with a configuration in which the substrate is etched by repeatedly supplying a liquid oxidant such as dilute hydrofluoric acid and an etching solution such as hydrogen peroxide water, the amount of substances used for etching the substrate can be reduced.

[0014] In one embodiment of the present invention, the substrate processing method further includes a first liquid removal step of removing the first rinse liquid from the main surface of the substrate after the first rinsing step and before the next first etching step is started. According to this substrate processing method, after the first polymer film is removed by the first rinse liquid and before a new first polymer film is formed, the first rinse liquid is removed from the main surface of the substrate. Therefore, it is possible to suppress the formed first polymer film from being removed by the first rinse liquid remaining on the main surface of the substrate. As a result, the first polymer film can sufficiently exhibit the etching action on the substrate, so that the etching amount of the substrate by one formation of the first polymer film can be increased. As a result, the amount of substances used for etching the substrate can be further reduced, and the environmental load can be reduced.

[0015] In addition, if the configuration is such that the first rinse liquid is removed from the main surface of the substrate to dry the main surface of the substrate, it is possible to further suppress the first rinse liquid from remaining on the main surface of the substrate at the start of the first etching step. In one embodiment of the present invention, the substrate processing method further includes a polymer-containing liquid supply step of supplying a polymer-containing liquid containing a solvent and a first acidic polymer to the main surface of the substrate before the first etching step. The first etching step includes a step of forming the first polymer film by evaporating at least a part of the solvent in the polymer-containing liquid on the main surface of the substrate.

[0016] According to this substrate processing method, a first polymer film can be formed by evaporating the solvent from the polymer-containing liquid supplied to the surface of the substrate. Therefore, the concentration of the acidic polymer in the first polymer film can be increased by the evaporation of the solvent. Thus, a high-concentration acidic polymer can be made to act on the substrate. Therefore, the substrate can be etched rapidly. In particular, the first oxide layer can be etched rapidly.

[0017] In one embodiment of this invention, after the last of the first rinsing steps, the substrate processing method further includes an oxidation step of performing an oxidation treatment on the main surface of the substrate, and after the oxidation step, a second etching step of forming a semi-solid or solid second polymer film containing a second acidic polymer on the main surface of the substrate to etch the substrate, and after the second etching step, a second rinsing step of supplying a second rinsing liquid to the main surface of the substrate.

[0018] According to this substrate processing method, after the last first rinsing step, an oxidation treatment is performed on the main surface of the substrate, and then the substrate is etched. Therefore, the substrate can be additionally etched to sufficiently ensure the etching amount. Therefore, the substrate can be etched better. In one embodiment of this invention, the second polymer film further contains a second alkali component. And the second etching step includes a second etching start step of starting the etching of the substrate by heating the second polymer film after the second polymer film is formed to evaporate the second alkali component from the second polymer film.

[0019] According to this configuration, a second alkaline component is contained in the second polymer film together with the second acidic polymer. Therefore, after the second polymer film is formed and before the second polymer film is heated, the second acidic polymer is neutralized by the second alkaline component and is almost deactivated. Therefore, almost no etching of the substrate is started after the second polymer film is formed and before the second polymer film is heated. By heating the second polymer film to evaporate the alkaline component, the second acidic polymer in the second polymer film regains its activity and the etching of the substrate is started. Therefore, the substrate can be etched with high precision. In particular, the start timing of the etching of the substrate can be accurately controlled.

[0020] In one embodiment of the present invention, the second polymer film further contains a second conductive polymer. Therefore, the ionization of the acidic polymer in the second polymer film can be promoted by the action of the second conductive polymer. Therefore, the second acidic polymer can effectively act on the oxide layer. That is, the second conductive polymer functions as a medium for the second acidic polymer to release protons (hydrogen ions). Therefore, even when the liquid components such as the solvent have completely disappeared from the second polymer film, if the second conductive polymer is contained in the second polymer film, the second acidic polymer can be ionized and the ionized second acidic polymer can act on the oxide layer.

[0021] In one embodiment of the present invention, the oxidation step includes a second oxide layer forming step of forming a second oxide layer on the surface layer portion of the main surface of the substrate. The second etching step includes a second oxide layer removing step of removing at least a part of the second oxide layer by the second acidic polymer in the second polymer film. And the second rinsing step includes a second polymer film removing step of removing the second polymer film from the main surface of the substrate with the second rinsing liquid after the second etching step.

[0022] According to this substrate processing method, after the first oxide layer exposed from the main surface of the substrate is removed by the first polymer film before the start of substrate processing, a second oxide layer is formed on the surface layer portion of the main surface of the substrate by oxidation treatment. Then, by forming and removing the second polymer film after the oxidation treatment, the substrate is further etched. Therefore, when the etching amount of the substrate is insufficient only by removing the first oxide layer, the second oxide layer is additionally formed, and then by removing the second oxide layer, a sufficient etching amount can be ensured.

[0023] Also, when removing the second oxide layer, a film containing a second acidic polymer (second polymer film) is used in the same manner as when removing the first oxide layer. Therefore, the usage amount of the substances required for etching the substrate can be reduced, so the environmental load can be reduced. In one embodiment of this invention, after the second rinsing step, the oxidation step, the second etching step, and the second rinsing step are further executed at least once in this order.

[0024] According to this substrate processing method, the oxidation step, the second etching step, and the second rinsing step are repeated. That is, the oxidation and etching of the substrate are executed a plurality of times. Therefore, the substrate can be additionally etched a plurality of times to ensure a sufficient etching amount. Specifically, the formation and removal of the second oxide layer are alternately executed a plurality of times. Therefore, the formation and removal of a small amount of the second oxide layer (for example, 1 nm or more and 10 nm or less) can be repeated. Therefore, compared with the case where a large amount of the second oxide layer is formed and removed at one time, it is easier to adjust the etching amount of the substrate. As a result, the substrate can be etched accurately.

[0025] In one embodiment of the present invention, the first acidic polymer is a carboxyl group-containing polymer, a sulfo group-containing polymer, or a mixture thereof. If the first acidic polymer is these polymers, water such as DIW (deionized water) can be used as the liquid for dissolving the first acidic polymer. Therefore, it is not necessary to use an organic solvent as the solvent for dissolving the first acidic polymer. Furthermore, it is not necessary to use an organic solvent as the first rinse liquid for removing each of the first polymer films. Therefore, the environmental load can be further reduced. Another embodiment of the present invention provides a substrate processing apparatus for etching a substrate having a main surface where an oxide layer is exposed. The substrate processing apparatus includes a polymer film forming unit that forms a semi-solid or solid polymer film containing an acidic polymer on the main surface of the substrate, and a rinse liquid supply unit that supplies a rinse liquid for cleaning the main surface of the substrate to the main surface of the substrate. According to this substrate processing apparatus, since the above-described substrate processing method can be executed, the same effects as the above-described substrate processing method can be obtained.

Brief Description of the Drawings

[0026]

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DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. <Structure of the surface layer portion of the substrate to be processed> FIG. 1 is a schematic cross-sectional view for explaining the structure of the surface layer portion of a substrate W to be processed. The substrate W is a substrate such as a silicon wafer and has a pair of main surfaces. At least one of the pair of main surfaces is a device surface on which a concavo-convex pattern 120 is formed. One of the pair of main surfaces may be a non-device surface on which the concavo-convex pattern 120 is not formed.

[0028] In the surface layer portion of the device surface, for example, an insulating layer 105 in which a plurality of trenches 122 are formed, a processing target layer 102 formed in each trench 122 so that the surface is exposed, and a first oxide layer 103 laminated on the processing target layer 102 are formed. The insulating layer 105 has fine convex structures 121 located between adjacent trenches 122 and a bottom partitioning portion 123 that partitions the bottom of the trench 122. The concavo-convex pattern 120 is constituted by the plurality of structures 121 and the plurality of trenches 122. The surface of the processing target layer 102 and the surface of the insulating layer 105 (structure 121) constitute at least a part of the main surface of the substrate W.

[0029] The insulating layer 105 is, for example, a silicon oxide (SiO 2 ) layer or a low dielectric constant layer. The low dielectric constant layer is made of a low dielectric constant (Low-k) material that is a material having a lower dielectric constant than silicon oxide. Specifically, the low dielectric constant layer is made of an insulating material (SiOC) obtained by adding carbon to silicon oxide. The layer 102 to be processed is, for example, a metal layer, a silicon layer, or the like. A typical metal layer is a copper wiring. The metal layer is formed, for example, by crystal growth using an electroplating technique or the like with a seed layer (not shown) formed in the trench 122 by a method such as sputtering as a nucleus. The method for forming the metal layer is not limited to this method. The metal layer may be formed only by sputtering or by other methods.

[0030] The first oxide layer 103 is, for example, a metal oxide layer, a silicon oxide layer, or the like. A typical metal oxide layer is a copper oxide layer. The first oxide layer 103 may be formed, for example, by oxidizing the surface layer portion of the layer 102 to be processed by a method such as anodic oxidation, thermal oxidation, ashing, or the like, or may be formed on the surface of the layer 102 to be processed by a method such as chemical vapor deposition (CVD). Further, the first oxide layer 103 may be a natural oxide film.

[0031] A barrier layer and a liner layer (not shown) may be provided between the layer 102 to be processed and the insulating layer 105 in the trench 122. The barrier layer is, for example, tantalum nitride (TaN), and the liner layer is, for example, ruthenium (Ru) or cobalt (Co). The trench 122 is, for example, linear. The width L of the linear trench 122 is the size of the trench 122 in a direction orthogonal to the direction in which the trench 122 extends and the thickness direction T of the substrate W. The widths L of the plurality of trenches 122 are not all the same, and at least two or more types of trenches 122 with different widths L are formed in the surface layer portion of the device surface of the substrate W. The width L is also the width of the layer 102 to be processed and the first oxide layer 103.

[0032] The width L of the trench 122 is, for example, 20 nm or more and 500 nm or less. The depth D of the trench 122 is the size of the trench 122 in the thickness direction T and is, for example, 200 nm or less. The plurality of trenches 122 may be connected to each other. Also, the trench 122 does not necessarily have to be linear and may be micropores (voids or pores). When the trench 122 is a micropore, the width L of the trench 122 is the diameter of the micropore.

[0033] Hereinafter, an example will be described in which the processing target layer 102 is a metal layer composed of a plurality of crystal grains 110, and the first oxide layer 103 is a metal oxide layer formed by oxidizing the processing target layer 102. In that case, the first oxide layer 103 is also composed of a plurality of crystal grains 110, similar to the processing target layer 102. The interface between the crystal grains 110 is called a grain boundary 111. The grain boundary 111 is a type of lattice defect and is formed by the disorder of the atomic arrangement.

[0034] The crystal grains 110 are less likely to grow as the width L of the trench 122 is narrower, and are more likely to grow as the width L of the trench 122 is wider. Therefore, smaller crystal grains 110 are more likely to be formed as the width L of the trench 122 is narrower, and larger crystal grains 110 are more likely to be formed as the width L of the trench 122 is wider. That is, the grain boundary density increases as the width L of the trench 122 is narrower, and the grain boundary density decreases as the width L of the trench 122 is wider.

[0035] <Configuration of the substrate processing apparatus according to the first embodiment> FIG. 2A is a plan view for explaining the configuration of the substrate processing apparatus 1 according to the first embodiment of the present invention. FIG. 2B is an elevation view for explaining the configuration of the substrate processing apparatus 1. The substrate processing apparatus 1 is a single-wafer type apparatus that processes the substrates W one by one. In this embodiment, the substrate W has a disk shape. In this embodiment, the substrate W is processed with the device surface facing upward.

[0036] The substrate processing apparatus 1 includes a plurality of processing units 2 that process a substrate W, a load port LP on which a carrier C that houses a plurality of substrates W to be processed by the processing units 2 is placed, transfer robots IR and CR that transfer the substrate W between the load port LP and the processing units 2, and a controller 3 that controls the substrate processing apparatus 1. The transfer robot IR transfers the substrate W between the carrier C and the transfer robot CR. The transfer robot CR transfers the substrate W between the transfer robot IR and the processing unit 2.

[0037] Each of the transfer robots IR and CR is, for example, a multi-joint arm robot including a pair of multi-joint arms AR and a pair of hands H respectively provided at the tips of the pair of multi-joint arms AR so as to be vertically spaced apart from each other. The plurality of processing units 2 form four processing towers respectively arranged at four horizontally separated positions. Each processing tower includes a plurality (three in this embodiment) of processing units 2 stacked in the vertical direction (see FIG. 2B). The four processing towers are arranged in pairs on both sides of a transfer path TR extending from the load port LP toward the transfer robots IR and CR (see FIG. 2A).

[0038] In the first embodiment, the processing unit 2 is a wet processing unit 2W that processes the substrate W with a liquid. Each wet processing unit 2W includes a chamber 4 and a processing cup 7 disposed in the chamber 4, and executes processing on the substrate W in the processing cup 7. The chamber 4 is formed with an entrance / exit (not shown) for loading and unloading the substrate W by the transfer robot CR. The chamber 4 is provided with a shutter unit (not shown) for opening and closing the entrance / exit.

[0039] FIG. 3 is a schematic cross-sectional view for explaining a configuration example of the wet processing unit 2W. The wet processing unit 2W further includes a spin chuck 5 that rotates the substrate W around a rotation axis A1 (vertical axis) while holding the substrate W at a predetermined holding position, and a heater unit 6 that heats the substrate W held by the spin chuck 5. The rotation axis A1 is a vertical straight line passing through the central portion of the substrate W. The holding position is the position of the substrate W shown in FIG. 3, and is the position where the substrate W is held in a horizontal posture.

[0040] The spin chuck 5 includes a spin base 21 having a disk shape along the horizontal direction, a plurality of chuck pins 20 that grip the substrate W above the spin base 21 and hold the substrate W at the holding position, a rotation shaft 22 whose upper end is connected to the spin base 21 and extends in the vertical direction, and a spin motor 23 that rotates the rotation shaft 22 around its central axis (rotation axis A1). The plurality of chuck pins 20 are arranged on the upper surface of the spin base 21 at intervals in the circumferential direction of the spin base 21. The spin motor 23 is an electric motor. The spin motor 23 rotates the rotation shaft 22, so that the spin base 21 and the plurality of chuck pins 20 rotate around the rotation axis A1. Thereby, the substrate W is rotated around the rotation axis A1 together with the spin base 21 and the plurality of chuck pins 20.

[0041] The plurality of chuck pins 20 are movable between a closed position where they contact the peripheral portion of the substrate W and grip the substrate W, and an open position where they retract from the peripheral portion of the substrate W. The plurality of chuck pins 20 are moved by an opening / closing unit 25. When the plurality of chuck pins 20 are in the closed position, they hold (clamp) the substrate W horizontally. When the plurality of chuck pins 20 are in the open position, while releasing the grip on the peripheral portion of the substrate W, they contact the peripheral portion of the lower surface (lower main surface) of the substrate W and support the substrate W from below.

[0042] The opening / closing unit 25 includes, for example, a link mechanism that moves the plurality of chuck pins 20, and a drive source that applies a driving force to the link mechanism. The drive source includes, for example, an electric motor. The heater unit 6 is an example of a substrate heating unit that heats the entire substrate W. The heater unit 6 has the form of a disc-shaped hot plate. The heater unit 6 is disposed between the upper surface of the spin base 21 and the lower surface of the substrate W. The heater unit 6 has a heating surface 6a that faces the lower surface of the substrate W from below.

[0043] The heater unit 6 includes a plate body 61 and a heater 62. The plate body 61 is slightly smaller than the substrate W in plan view. The upper surface of the plate body 61 constitutes the heating surface 6a. The heater 62 may be a resistor built into the plate body 61. By energizing the heater 62, the heating surface 6a is heated. The heater 62 can heat the substrate W to a temperature approximately equal to the temperature of the heater 62. The heater 62 is configured to be able to heat the substrate W within a temperature range from room temperature (for example, a temperature of 5°C or higher and 25°C or lower) to 400°C or lower.

[0044] Connected to the lower surface of the heater unit 6 is a lifting shaft 66 that is inserted into a through hole 21a formed in the central portion of the spin base 21 and a hollow rotating shaft 22. The heater 62 is connected to an energization unit 64 such as a power source via a power supply line 63, and by adjusting the current supplied from the energization unit 64, the temperature of the heater 62 changes to a temperature within the above-described temperature range.

[0045] The heater unit 6 is lifted and lowered by a heater lifting drive mechanism 65. The heater lifting drive mechanism 65 includes, for example, an actuator (not shown) such as an electric motor or an air cylinder that drives the lifting shaft 66 up and down. The heater lifting drive mechanism 65 lifts and lowers the heater unit 6 via the lifting shaft 66. The heater unit 6 can be lifted and lowered between the lower surface of the substrate W and the upper surface of the spin base 21.

[0046] When rising, the heater unit 6 can receive the substrate W from a plurality of chuck pins 20 located at the open position. The heater unit 6 can heat the substrate W by being disposed at a contact position where the heating surface 6a contacts the lower surface of the substrate W or at a proximity position where it is close to and non-contact with the lower surface of the substrate W. A retracted position is a position where the heater unit 6 is sufficiently retracted from the lower surface of the substrate W to such an extent that the heating of the substrate W by the heater unit 6 is stopped.

[0047] Above the spin base 21, a shielding plate 35 is provided that blocks the atmosphere in the space between the upper surface (upper main surface) of the substrate W held by the spin chuck 5 from the atmosphere outside the space. The shielding plate 35 has a facing surface 35a that faces the upper surface of the substrate W held by the spin chuck 5 from above. The shielding plate 35 is formed in a disk shape having a diameter approximately the same as or larger than that of the substrate W. A support shaft 36 is fixed to the side of the shielding plate 35 opposite to the facing surface 35a.

[0048] The shielding plate 35 is connected to a shielding plate elevating mechanism 37 that raises and lowers the shielding plate 35. The shielding plate elevating mechanism 37 includes, for example, an actuator (not shown) such as an electric motor or an air cylinder that drives the support shaft 36 to move up and down. The shielding plate 35 may be rotatable about the rotation axis A1. The facing surface 35a is provided with a gas discharge port 38 that discharges a gas such as nitrogen gas. The gas discharged from the gas discharge port 38 is not limited to nitrogen gas. The gas discharged from the gas discharge port 38 may be air. Also, the gas discharged from the gas discharge port 38 may be an inert gas other than nitrogen gas. An inert gas is not limited to nitrogen gas and is a gas that is inert with respect to the upper surface of the substrate W. Examples of inert gases include noble gases such as argon in addition to nitrogen gas.

[0049] The gas outlet 38 is connected to a gas pipe 43 that guides the gas to the gas outlet 38. The gas pipe 43 is interposed with a gas valve 53A that opens and closes the flow path in the gas pipe 43 and a gas flow rate adjustment valve 53B that adjusts the flow rate of the gas in the flow path. When the gas valve 53A is opened, the gas is discharged from the gas outlet 38 toward the upper surface of the substrate W at a flow rate corresponding to the opening degree of the gas flow rate adjustment valve 53B.

[0050] The processing cup 7 receives the liquid scattered from the substrate W held by the spin chuck 5. The processing cup 7 includes a plurality (two in the example of FIG. 3) of guards 30 that receive the liquid scattered outward from the substrate W held by the spin chuck 5, a plurality (two in the example of FIG. 3) of cups 31 that receive the liquid guided downward by the plurality of guards 30, and a cylindrical outer wall member 32 that surrounds the plurality of guards 30 and the plurality of cups 31. The plurality of guards 30 are individually lifted and lowered by a guard lifting and lowering drive mechanism (not shown). The guard lifting and lowering drive mechanism positions the guard 30 at an arbitrary position from the upper position to the lower position.

[0051] The wet processing unit 2W further includes a polymer-containing liquid nozzle 10 that supplies a polymer-containing liquid containing an acidic polymer to the upper surface of the substrate W held by the spin chuck 5, and a rinse liquid nozzle 11 that supplies a rinse liquid such as DIW (Deionized Water) to the upper surface of the substrate W held by the spin chuck 5. The polymer-containing liquid contains a solute and a solvent that dissolves the solute. The solute of the polymer-containing liquid includes an acidic polymer, an alkaline component, and a conductive polymer.

[0052] The acidic polymer is an acidic polymer that dissolves the oxide layer without oxidizing the layer to be processed. The acidic polymer is solid at room temperature and exhibits acidity by releasing protons in a solvent. The molecular weight of the acidic polymer is, for example, 1000 or more and 100000 or less. The acidic polymer is not limited to polyacrylic acid. The acidic polymer is, for example, a carboxyl group-containing polymer, a sulfo group-containing polymer, or a mixture thereof. The carboxylic acid polymer is, for example, polyacrylic acid, carboxyvinyl polymer (carbomer), carboxymethyl cellulose, or a mixture thereof. The sulfo group-containing polymer is, for example, polystyrene sulfonic acid, polyvinyl sulfonic acid, or a mixture thereof.

[0053] The solvent contained in the polymer-containing liquid is a liquid at room temperature and can dissolve or swell the acidic polymer, and any substance that can evaporate by rotation or heating of the substrate W may be used. The solvent contained in the polymer-containing liquid is not limited to DIW, but is preferably an aqueous solvent. The solvent contains at least one of DIW, carbonated water, electrolyzed ionized water, hydrochloric acid water with a dilution concentration (for example, 1 ppm or more and 100 ppm or less), ammonia water with a dilution concentration (for example, 1 ppm or more and 100 ppm or less), and reduced water (hydrogen water).

[0054] The alkali component is, for example, ammonia. The alkali component is not limited to ammonia. Specifically, the alkali component includes, for example, ammonia, tetramethylammonium hydroxide (TMAH), dimethylamine, or a mixture thereof. The alkali component is preferably a component that evaporates by heating to a temperature below the boiling point of the solvent and exhibits alkalinity in the solvent. The alkali component is particularly preferably ammonia or dimethylamine, which are gases at room temperature, and mixtures thereof.

[0055] Conductive polymers are not limited to polyacetylene. Conductive polymers are conjugated polymers having conjugated double bonds. Conjugated polymers include, for example, aliphatic conjugated polymers such as polyacetylene, aromatic conjugated polymers such as poly(p-phenylene), mixed conjugated polymers such as poly(p-phenylene vinylene), heterocyclic conjugated polymers such as polypyrrole, polythiophene, poly(3,4-ethylenedioxythiophene) (PEDOT), heteroatom-containing conjugated polymers such as polyaniline, double-chain conjugated polymers such as polyacene, two-dimensional conjugated polymers such as graphene, or mixtures thereof.

[0056] The polymer-containing liquid nozzle 10 is a movable nozzle at least in the horizontal direction. The polymer-containing liquid nozzle 10 is moved horizontally by the first nozzle moving unit 33. The first nozzle moving unit 33 includes an arm (not shown) that is coupled to the polymer-containing liquid nozzle 10 and extends horizontally, and an arm moving unit that moves the arm in the horizontal direction. The arm moving unit may be an electric motor or an air cylinder, or may be other actuators.

[0057] The polymer-containing liquid nozzle 10 may be movable in the vertical direction. By moving in the vertical direction, the polymer-containing liquid nozzle 10 can approach the upper surface of the substrate W or retract upward from the upper surface of the substrate W. Different from this embodiment, the polymer-containing liquid nozzle 10 may be a fixed nozzle with fixed horizontal and vertical positions. The polymer-containing liquid nozzle 10 is connected to one end of a polymer-containing liquid pipe 41 that guides the polymer-containing liquid to the polymer-containing liquid nozzle 10. The other end of the polymer-containing liquid pipe 41 is connected to a polymer-containing liquid tank (not shown). A polymer-containing liquid valve 51A that opens and closes the flow path in the polymer-containing liquid pipe 41 and a polymer-containing liquid flow rate adjustment valve 51B that adjusts the flow rate of the polymer-containing liquid in the flow path are interposed in the polymer-containing liquid pipe 41.

[0058] When the polymer-containing liquid valve 51A is opened, the polymer-containing liquid is discharged continuously downward from the discharge port of the polymer-containing liquid nozzle 10 at a flow rate corresponding to the opening degree of the polymer-containing liquid flow rate adjustment valve 51B. At least a part of the solvent evaporates from the polymer-containing liquid supplied to the upper surface of the substrate W, so that the polymer-containing liquid on the substrate W changes into a semi-solid or solid polymer film. The semi-solid state means a state in which a solid component and a liquid component are mixed, or a state having a viscosity such that a certain shape can be maintained on the substrate W. The solid state means a state in which no liquid component is contained and which is composed only of a solid component. A polymer film in which the solvent remains is semi-solid, and a polymer film in which the solvent has completely disappeared is solid.

[0059] The polymer-containing liquid contains, as solutes, in addition to the acidic polymer, an alkali component and a conductive polymer. Therefore, the polymer film contains the acidic polymer, the alkali component, and the conductive polymer. When the polymer film contains an alkali component and an acidic polymer, the polymer film is neutral. That is, the acidic polymer is neutralized by the alkali component and is almost inactivated. Therefore, the dissolution of the oxide layer of the substrate W due to the action of the acidic polymer hardly occurs. If the polymer film is heated to evaporate the alkali component from the polymer film, the acidic polymer regains its activity. That is, the oxide layer of the substrate W is dissolved by the action of the acidic polymer.

[0060] It is preferable that the solvent remains in the polymer film without being completely evaporated. If so, the acidic polymer in the polymer film can fully exhibit its function as an acid, so that the oxide layer can be efficiently removed. If the solvent remains, when the alkali component is present in the polymer film, the polymer film is neutral, and after the alkali component has evaporated, the polymer film is acidic.

[0061] Similar to the solvent, the conductive polymer functions as a medium for the acidic polymer to release protons (hydrogen ions). Therefore, even when the solvent has completely disappeared from the polymer film, the acidic polymer can be ionized and made to act on the oxide layer. Also, by moderately evaporating the solvent in the polymer film, the concentration of the acidic polymer component dissolved in the solvent in the polymer film can be increased. As a result, the first oxide layer can be efficiently removed. Also, the higher the temperature of the polymer film, the more the chemical reaction for removing (dissolving) the oxide layer by the acidic polymer is promoted. That is, the acidic polymer has the property that the higher the temperature, the higher the rate of removal of the oxide layer. Therefore, the first oxide layer can be efficiently removed by heating the polymer film formed on the upper surface of the substrate W.

[0062] The rinse liquid nozzle 11 is an example of a rinse liquid supply unit that supplies rinse liquid to the main surface of the substrate W. The rinse liquid functions as a polymer removal liquid (first polymer removal liquid) that dissolves the polymer film formed on the upper surface of the substrate W and removes it from the main surface of the substrate W, and the rinse liquid nozzle 11 functions as a removal liquid supply unit. The rinse liquid is not limited to DIW. The rinse liquid contains at least one of DIW, carbonated water, electrolyzed ionized water, hydrochloric acid water with a dilution concentration (for example, 1 ppm or more and 100 ppm or less), ammonia water with a dilution concentration (for example, 1 ppm or more and 100 ppm or less), and reduced water (hydrogen water). That is, as the rinse liquid, a liquid similar to the solvent of the polymer-containing liquid can be used. If DIW is used for both the rinse liquid and the solvent of the polymer-containing liquid, the types of liquids (substances) used can be reduced.

[0063] In this embodiment, the rinse liquid nozzle 11 is a fixed nozzle with a fixed horizontal position and vertical position. Different from this embodiment, the rinse liquid nozzle 11 may be a movable nozzle that is movable at least in the horizontal direction. The rinse liquid nozzle 11 is connected to one end of a rinse liquid pipe 42 that guides the rinse liquid to the rinse liquid nozzle 11. The other end of the rinse liquid pipe 42 is connected to a rinse liquid tank (not shown). The rinse liquid pipe 42 is interposed with a rinse liquid valve 52A that opens and closes the flow path in the rinse liquid pipe 42 and a rinse liquid flow rate adjustment valve 52B that adjusts the flow rate of the rinse liquid in the flow path. When the rinse liquid valve 52A is opened, the rinse liquid discharged in a continuous flow from the discharge port of the rinse liquid nozzle 11 adheres to the upper surface of the substrate W.

[0064] FIG. 4 is a block diagram for explaining a configuration example related to the control of the substrate processing apparatus 1. The controller 3 includes a microcomputer and controls a control target provided in the substrate processing apparatus 1 according to a predetermined control program. Specifically, the controller 3 includes a processor (CPU) 3A and a memory 3B in which the control program is stored. The controller 3 is configured to execute various controls for substrate processing when the processor 3A executes the control program.

[0065] In particular, the controller 3 is programmed to control each member (valve, motor, power supply, etc.) constituting the processing unit 2, transfer robots IR, CR, etc. By controlling the valve by the controller 3, the presence or absence of the discharge of the fluid from the corresponding nozzle and the discharge flow rate of the fluid from the corresponding nozzle are controlled. The following respective steps are executed by the controller 3 controlling these configurations. In other words, the controller 3 is programmed to execute the following respective steps.

[0066] <Substrate Processing According to the First Embodiment> FIG. 5 is a flowchart for explaining an example of the substrate processing executed by the substrate processing apparatus 1. FIGS. 6A to 6F are schematic diagrams for explaining the states of the respective steps of the substrate processing executed by the substrate processing apparatus 1. Hereinafter, the substrate processing executed by the substrate processing apparatus 1 will be mainly described with reference to FIGS. 3 and 5. FIGS. 6A to 6F will be referred to as appropriate.

[0067] First, a substrate W having a main surface on which a first oxide layer is exposed is prepared (substrate preparation step). Specifically, a carrier C containing a substrate W having a main surface on which a first oxide layer is exposed is placed on a load port LP. The substrate W is carried into the wet processing unit 2W from the carrier C by transfer robots IR and CR (see FIG. 2A) and passed to a plurality of chuck pins 20 of a spin chuck 5 (substrate loading step: step S1). The opening / closing unit 25 moves the plurality of chuck pins 20 to the closed position, whereby the substrate W is gripped by the plurality of chuck pins 20. Thereby, the substrate W is horizontally held by the spin chuck 5 (substrate holding step). With the substrate W held by the spin chuck 5, the spin motor 23 starts rotating the substrate W (substrate rotation step).

[0068] Next, after the transfer robot CR retreats outside the wet processing unit 2W, a first polymer-containing liquid supply step (step S2) of supplying a polymer-containing liquid to the upper surface of the substrate W is executed. Specifically, the first nozzle moving unit 33 moves the polymer-containing liquid nozzle 10 to the processing position. The processing position of the polymer-containing liquid nozzle 10 is, for example, a central position where the polymer-containing liquid nozzle 10 faces the central region of the upper surface of the substrate W. The central region of the upper surface of the substrate W is a region including the center position of the upper surface of the substrate W and the periphery of the center position. With the polymer-containing liquid nozzle 10 positioned at the processing position, the polymer-containing liquid valve 51A is opened. When the polymer-containing liquid valve 51A is opened, as shown in FIG. 6A, the polymer-containing liquid is discharged from the polymer-containing liquid nozzle 10 toward the central region of the upper surface of the substrate W (polymer-containing liquid discharge step). The polymer-containing liquid discharged from the polymer-containing liquid nozzle 10 lands on the central region of the upper surface of the substrate W.

[0069] While supplying the polymer-containing liquid onto the upper surface of the substrate W, the substrate W may be rotated at a low speed (e.g., 10 rpm) (low-speed rotation step). Alternatively, while supplying the polymer-containing liquid onto the upper surface of the substrate W, the rotation of the substrate W may be stopped. By setting the rotation speed of the substrate W to a low speed or stopping the rotation of the substrate W, the polymer-containing liquid supplied to the substrate W stays in the central region of the upper surface of the substrate W. Thereby, the usage amount of the polymer-containing liquid can be reduced.

[0070] Next, as shown in FIGS. 6B and 6C, a first polymer film forming step (step S3) of forming a solid or semi-solid polymer film 101 (first polymer film) (see FIG. 6C) on the upper surface of the substrate W by evaporating at least a part of the solvent in the polymer-containing liquid on the upper surface of the substrate W is executed. The acidic polymer, alkaline component, and conductive polymer contained in the first polymer film are examples of a first acidic polymer, a first alkaline component, and a first conductive polymer, respectively.

[0071] Specifically, the polymer-containing liquid valve 51A is closed to stop the discharge of the polymer-containing liquid from the polymer-containing liquid nozzle 10. After the polymer-containing liquid valve 51A is closed, the polymer-containing liquid nozzle 10 is moved to the retracted position by the first nozzle moving unit 33. When the polymer-containing liquid nozzle 10 is located at the retracted position, it does not face the upper surface of the substrate W and is located outside the processing cup 7 in plan view.

[0072] After the polymer-containing liquid valve 51A is closed, as shown in FIG. 6B, the rotation of the substrate W is accelerated so that the rotation speed of the substrate W becomes a predetermined spin-off speed (rotation acceleration step). The spin-off speed is, for example, 1500 rpm. The rotation of the substrate W at the spin-off speed is continued for, for example, 30 seconds. The polymer-containing liquid remaining in the central region of the upper surface of the substrate W is spread toward the peripheral portion of the upper surface of the substrate W by the centrifugal force caused by the rotation of the substrate W. As a result, the polymer-containing liquid is spread over the entire upper surface of the substrate W. As shown in FIG. 6B, a part of the polymer-containing liquid on the substrate W scatters out of the substrate W from the peripheral portion of the substrate W, and the liquid film of the polymer-containing liquid on the substrate W is thinned (spin-off process).

[0073] The polymer-containing liquid on the upper surface of the substrate W does not need to scatter out of the substrate W, and it may be spread over the entire upper surface of the substrate W by the action of the centrifugal force of the rotation of the substrate W. The centrifugal force caused by the rotation of the substrate W acts not only on the polymer-containing liquid on the substrate W but also on the gas in contact with the polymer-containing liquid on the substrate W. Therefore, due to the action of the centrifugal force, an air flow is formed in which the gas moves from the center side to the peripheral side of the upper surface of the substrate W. By this air flow, the gaseous solvent in contact with the polymer-containing liquid on the substrate W is excluded from the atmosphere in contact with the substrate W. Therefore, as shown in FIG. 6C, the evaporation (volatilization) of the solvent from the polymer-containing liquid on the substrate W is promoted, and a solid or semi-solid polymer film 101 is formed (first polymer film forming step). Thus, the polymer-containing liquid nozzle 10 and the spin motor 23 function as a polymer film forming unit.

[0074] Since the polymer film 101 has a higher viscosity than the polymer-containing liquid, it remains on the substrate W without being completely removed from the substrate W even though the substrate W is rotating. Immediately after the polymer film 101 is formed, the polymer film 101 contains an alkaline component. Therefore, since the acidic polymer in the polymer film 101 is deactivated, the removal of the oxide layer is not performed.

[0075] With the polymer film 101 formed on the upper surface of the substrate W, a first polymer film heating step (step S4) of heating the polymer film 101 on the substrate W is executed. Specifically, as shown in FIG. 6D, the heater unit 6 is disposed in a proximity position, and the substrate W is heated (substrate heating step, heater heating step). The polymer film 101 formed on the substrate W is heated through the substrate W. When the polymer film 101 is heated, the alkali component evaporates, and the acidic polymer recovers its activity (alkali component evaporation step, alkali component removal step). Therefore, etching of the substrate W is started by the action of the acidic polymer in the polymer film 101 (first etching start step, etching step).

[0076] Specifically, removal of the oxide layer formed on the surface layer portion of the upper surface of the substrate W is started (oxide layer removal start step, oxide layer removal step). After the polymer film 101 is formed and until the polymer film 101 is heated, the acidic polymer is neutralized by the alkali component and is almost inactivated. Therefore, etching of the substrate W hardly starts after the polymer film 101 is formed and until the polymer film 101 is heated.

[0077] As described above, the acidic polymer has the property that the higher the temperature, the higher the removal rate of the first oxide layer. Therefore, even after the alkali component is removed from the polymer film 101, by continuing to heat the polymer film 101, removal of the first oxide layer by the acidic polymer is promoted (first removal promotion step). By promoting the removal of the first oxide layer, the time required for substrate processing can be reduced. Different from FIG. 6D, in the first polymer film heating step, the heater unit 6 may be arranged at the contact position.

[0078] When the polymer film 101 is heated, the solvent in the polymer film 101 evaporates. Therefore, the concentration of the acidic polymer dissolved in the solvent in the polymer film 101 increases (polymer concentration step). Thereby, the concentration of the acidic polymer increases and the removal rate of the first oxide layer by the action of the acidic polymer is improved. The heating temperature of the substrate W is preferably lower than the boiling point of the solvent in the polymer film 101. If so, the solvent can be moderately evaporated from the polymer film 101 on the substrate W. Therefore, the concentration of the acidic polymer dissolved in the solvent in the polymer film 101 can be increased. Furthermore, it is possible to suppress the solvent from completely evaporating and being completely removed from the polymer film 101.

[0079] Next, after heating the polymer film 101 through the substrate W is performed for a predetermined time, a first polymer film removal step (step S5) for removing the polymer film 101 on the substrate W is executed. Specifically, the heater unit 6 retracts to the retracted position, and the rinse liquid valve 52A is opened. By opening the rinse liquid valve 52A, as shown in FIG. 6E, the rinse liquid is supplied (discharged) from the rinse liquid nozzle 11 toward the central region of the upper surface of the substrate W on which the polymer film 101 is formed (rinse liquid supply step, rinse liquid discharge step). The rinse liquid discharged from the rinse liquid nozzle 11 lands on the central region of the upper surface of the substrate W.

[0080] While supplying the rinse liquid to the upper surface of the substrate W, the substrate W is rotated at a predetermined rinse speed (for example, 800 rpm). The rinse liquid that has landed on the central region of the upper surface of the rotating substrate W spreads from the central region of the substrate W toward the peripheral side. The polymer film 101 on the substrate W is dissolved by the rinse liquid that has landed on the upper surface of the substrate W (first polymer film dissolution step). By continuing to supply the rinse liquid to the substrate W, the polymer film 101 is removed from the upper surface of the substrate W (first polymer film removal step). Due to the dissolving action of the rinse liquid and the flow of the rinse liquid formed on the upper surface of the substrate W, the polymer film 101 is removed from the upper surface of the substrate W. In this way, the main surface of the substrate W is cleaned by the rinse liquid (first rinse liquid) (first rinse step).

[0081] After supplying the rinse liquid for a certain period of time, a first liquid removal step (step S6) for removing the rinse liquid on the upper surface of the substrate W from the upper surface of the substrate W is executed. Specifically, the rinse liquid valve 52A is closed, and the supply of the rinse liquid to the upper surface of the substrate W is stopped. Then, the spin motor 23 accelerates the rotation of the substrate W to rotate the substrate W at a high speed. The substrate W is rotated at a predetermined drying speed, for example, 1500 rpm. Thereby, as shown in FIG. 6F, a large centrifugal force acts on the rinse liquid on the substrate W, and the rinse liquid on the substrate W is thrown off around the substrate W. Thereby, the upper surface of the substrate W is dried (drying step).

[0082] When removing the rinse liquid from the upper surface of the substrate W, gas may be discharged from the gas discharge port 38 provided on the opposing surface 35a of the shielding plate 35 toward the central region of the upper surface of the substrate W (gas discharge step). The gas colliding with the upper surface of the substrate W forms an air flow that spreads from the central region of the substrate W toward the peripheral side along the upper surface of the substrate W. By this air flow, the removal of the rinse liquid on the substrate W can be promoted.

[0083] After removing the rinse liquid from the upper surface of the substrate W, the first oxide layer may be further removed by forming the polymer film 101 on the upper surface of the substrate W again. That is, after the first polymer film removing step (strictly speaking, the first liquid removing step), the first polymer film forming step (the first etching step) and the first polymer film removing step (the first rinsing step) may be further executed at least once in this order. More specifically, the cycle process with the first polymer-containing liquid supply step (step S2) to the first liquid removing step (step S6) as one cycle (hereinafter sometimes referred to as "the first cycle process") may be performed two or more times.

[0084] "N" in FIG. 5 means an integer of 0 or more. When "N" is 0, the first polymer-containing liquid supply step (step S2) to the first liquid removing step (step S6) are each performed once, and when "N" is 1 or more, the first polymer-containing liquid supply step (step S2) to the first liquid removing step (step S6) are each performed two or more times. That is, when "N" is 1 or more, the first cycle process is performed a plurality of times.

[0085] For example, when the first oxide layer can be removed by a desired amount in a single first etching process, it is not necessary to execute the first cycle process, and it is sufficient to execute the first polymer-containing liquid supply process (step S2) to the first liquid removal process (step S6) once each. Conversely, when the first oxide layer cannot be removed by a desired amount in a single first etching process, it is preferable to execute the first cycle process. By forming and removing the polymer film 101 one or more times, the first oxide layer is removed from the upper surface of the substrate W and the layer to be processed is exposed.

[0086] When "N" is 1 or more, the first polymer film forming process (first oxide layer removing process) and the first polymer film removing process are alternately repeated. In other words, the first polymer film forming process (first oxide layer removing process) and the first polymer film removing process are alternately executed a plurality of times each. Even when the first oxide layer 103 is not etched by a desired amount in a single formation and removal of the polymer film 101, the first oxide layer 103 can be sufficiently etched by executing the formation and removal of the polymer film 101 a plurality of times. For example, the first oxide layer 103 may be completely removed from the substrate W by forming and removing the polymer film 101 a plurality of times.

[0087] After the last first liquid removal process (step S6), the spin motor 23 stops the rotation of the substrate W. The transfer robot CR enters the wet processing unit 2W, receives the processed substrate W from the plurality of chuck pins 20, and carries it out of the wet processing unit 2W (substrate carry-out process: step S7). The substrate W is passed from the transfer robot CR to the transfer robot IR and stored in the carrier C by the transfer robot IR.

[0088] According to the first embodiment, at least a part of the first oxide layer 103 is removed from the substrate W by the acidic polymer in the polymer film 101 formed on the upper surface of the substrate W. Thereafter, since the upper surface of the substrate W is cleaned with the first rinse liquid, the polymer film 101 is removed from the upper surface of the substrate W. Therefore, etching of the substrate W can be started by forming the polymer film 101, and the etching of the substrate W can be stopped by removing the polymer film 101 from the upper surface of the substrate W. Therefore, since the etching amount of the first oxide layer 103 can be adjusted by forming and removing the polymer film 101, the substrate W can be etched favorably.

[0089] Since the polymer film 101 used for removing the first oxide layer 103 is in a semi-solid state or a solid state, it is easier to stay on the upper surface of the substrate W compared to a liquid. Therefore, it is not necessary to continuously supply the acidic polymer-containing liquid to the upper surface of the substrate W during the entire period while removing the first oxide layer 103. In other words, at least after forming the polymer film 101, it is not necessary to additionally supply the acidic polymer-containing liquid to the upper surface of the substrate W. Therefore, the usage amount of the acidic polymer, which is a substance required for etching the substrate W, can be reduced. As a result, the usage amount of the substance used for etching the substrate can be reduced.

[0090] Also according to the first embodiment, after the polymer film 101 is removed by the rinse liquid and before a new polymer film 101 is formed, the rinse liquid on the upper surface of the substrate W is removed. Therefore, it is possible to suppress the polymer film 101 being formed from being removed by the rinse liquid remaining on the upper surface of the substrate W. As a result, since the polymer film 101 can fully exhibit the etching action on the substrate W, the etching amount of the substrate W by one formation of the polymer film can be increased. As a result, the usage amount of the substance required for etching the substrate W can be further reduced, so that the environmental load can be reduced.

[0091] Also according to the first embodiment, the polymer film 101 can be formed by evaporating the solvent from the polymer-containing liquid supplied onto the upper surface of the substrate W. Therefore, the concentration of the acidic polymer in the polymer film 101 can be increased by the evaporation of the solvent. Accordingly, a high-concentration acidic polymer can act on the first oxide layer 103. Therefore, the substrate W can be etched rapidly.

[0092] Also according to the first embodiment, the acidic polymer is a carboxyl group-containing polymer, a sulfo group-containing polymer, a hydroxy group-containing polymer, or a mixture thereof. Therefore, water such as DIW can be used as the liquid for dissolving the acidic polymer. Therefore, it is not necessary to use an organic solvent as the solvent for dissolving the acidic polymer and the rinse liquid for removing the polymer film 101. Accordingly, the environmental load can be further reduced.

[0093] When removing the first oxide layer 103 with a continuous-flow etching solution, the temperature of the etching solution decreases as the etching solution moves from the center side to the peripheral side of the upper surface of the substrate W. Therefore, due to the decrease in the temperature of the etching solution, the etching amount (the removal amount of the first oxide layer 103) in the peripheral region of the upper surface of the substrate W becomes lower than the etching amount in the central region of the upper surface of the substrate W, and the uniformity of the etching amount at each position on the upper surface of the substrate W may decrease.

[0094] On the other hand, according to the first embodiment, the entire upper surface of the substrate W is covered with the semi-solid or solid polymer film 101, and the first oxide layer 103 is removed by the action of the acidic polymer in the polymer film 101. Therefore, in the state where the polymer film 101 is formed, since the acidic polymer does not move from the center side to the peripheral side of the upper surface of the substrate W, the temperature of the portion of the polymer film 101 in contact with each position on the upper surface of the substrate W changes almost uniformly. Therefore, the uniformity of the etching amount can be improved.

[0095] Unlike the first embodiment, in the configuration where the first oxide layer 103 is removed with a continuous flow of etching solution, when the width L of the trench 122 formed on the upper surface of the substrate W is narrow, the liquid that has entered the trench 122 may not be sufficiently replaced with the etching solution. Therefore, when a plurality of trenches 122 having different widths L are formed on the upper surface of the substrate W, the degree of replacement of the liquid that has entered the trench 122 with the etching solution varies, and the uniformity of the etching amount on the upper surface of the substrate W may decrease.

[0096] On the other hand, according to the first embodiment, as shown in FIG. 7, the polymer film 101 is formed so as to follow the processing target layer 102 and the trench 122 regardless of the width L of the trench 122. Specifically, the polymer film 101 is formed along the surface 103a of the first oxide layer 103, the side surface 122a of the trench 122, and the top 121a of the structure 121. Therefore, even when trenches 122 having different widths L are formed, variations in the etching amount of the processing target layer 102 between the trenches 122 can be reduced.

[0097] As shown in FIGS. 8A and 8B, the distance between the constituent substances 116 that constitute the first oxide layer 103 at the grain boundary 111 is wider than the distance between the constituent substances 116 in the grain 110. Therefore, a gap 113 exists between the constituent substances 116 at the grain boundary 111. The constituent substance 116 is, for example, a molecule, and typically, a copper oxide molecule.

[0098] Unlike the first embodiment, when removing the first oxide layer 103 with an etching solution containing a low-molecular-weight etching component 114 such as hydrofluoric acid as shown in FIG. 8A, the low-molecular-weight etching component 114 easily enters the gaps 113 present at the grain boundaries 111 of the substrate W. Therefore, the first oxide layer 103 is easily removed at locations with a high grain boundary density (within the trench 122 with a narrow width L), and the first oxide layer 103 is difficult to remove at locations with a low grain boundary density (within the trench 122 with a wide width L). Thus, it is difficult to uniformly remove the first oxide layer 103, and there is a possibility that the roughness (surface roughness) of the upper surface of the substrate W increases.

[0099] On the other hand, according to the first embodiment, as shown in FIG. 8B, the acidic polymer 115, which is a high-molecular-weight etching component, is less likely to enter the gaps 113 present at the grain boundaries 111 than the low-molecular-weight etching component 114. Therefore, regardless of the grain boundary density, the first oxide layer 103 can be etched uniformly. The roughness of the upper surface of the substrate W can be reduced by the first oxide layer 103.

[0100] Also, in the first embodiment, when the first cycle process is executed multiple times, the first oxide layer removal process is executed again after the first polymer film removal process. As a result, after the polymer film 101 formed on the upper surface of the substrate W is once removed, the polymer film 101 is formed again on the upper surface of the substrate W. Therefore, the polymer film 101 in which the acidic polymer has been consumed due to the removal of the first oxide layer 103 can be removed from the upper surface of the substrate W, and the first oxide layer 103 can be removed by the new polymer film 101. Thus, compared with a configuration in which the substrate W is etched by repeatedly supplying a liquid oxidizing agent such as dilute hydrofluoric acid and an etching solution such as hydrogen peroxide water, the usage amount of the substances required for etching the substrate W can be reduced.

[0101] In addition, in the first embodiment, when the first cycle process is executed multiple times, after the polymer film 101 is removed by the rinse liquid and before a new polymer film 101 is formed, the rinse liquid is removed from the upper surface of the substrate W. Therefore, it is possible to suppress the polymer film 101 being formed from being removed by the rinse liquid remaining on the upper surface of the substrate W. As a result, the polymer film 101 can fully exhibit the removing effect on the first oxide layer 103, so that the removal amount of the first oxide layer 103 by one-time polymer film formation can be increased. As a result, the usage amount of the substances required for etching the substrate W can be further reduced, and thus the environmental load can be reduced.

[0102] According to the first embodiment, by heating the polymer film 101 to evaporate the alkaline component, the acidic polymer in the polymer film 101 regains its activity and etching is started. Therefore, the substrate W can be etched with high precision. In particular, the start timing of etching the substrate W can be accurately controlled. Also according to the first embodiment, the ionization of the acidic polymer in the polymer film 101 can be promoted by the action of the conductive polymer. Therefore, the acidic polymer can effectively act on the first oxide layer 103.

[0103] <Second Embodiment> FIG. 9 is a schematic cross-sectional view for explaining a configuration example of a wet processing unit 2W provided in a substrate processing apparatus 1P according to the second embodiment. The substrate processing apparatus 1P according to the second embodiment is mainly different from the substrate processing apparatus 1 according to the first embodiment in that the wet processing unit 2W further includes an oxidant nozzle 13 that supplies a liquid oxidant such as hydrogen peroxide water to the upper surface of the substrate W held by the spin chuck 5.

[0104] The liquid oxidant is a liquid that oxidizes the surface layer portion of the processing target layer exposed from the upper surface of the substrate W to form a second oxide layer on the surface layer portion of the processing target layer 102. The second oxide layer formed by the liquid oxidant has a thickness of, for example, 1 nm or more and 2 nm or less. The second oxide layer is formed by oxidizing the layer to be processed. Therefore, when the layer to be processed is a metal layer, the second oxide layer is a metal oxide layer, and when the layer to be processed is a silicon layer, the second oxide layer is a silicon oxide layer. The second oxide layer has the same properties as the first oxide layer. Therefore, the second oxide layer can be removed by the acidic polymer in the polymer film 101.

[0105] The liquid oxidant is, for example, hydrogen peroxide water (H 2 O 2 ) containing hydrogen peroxide (H 2 O 2 water) and APM solution (ammonia hydrogen peroxide water mixture), ozone water (O 3 ) containing ozone (O 3 water), etc. The oxidant does not necessarily have to be hydrogen peroxide or ozone. The oxidant may be any oxidant that can oxidize the layer to be processed exposed from the upper surface of the substrate W. For example, the liquid oxidant may contain a plurality of oxidants. Specifically, the liquid oxidant may be a liquid formed by dissolving both hydrogen peroxide and ozone in water such as DIW. The oxidant nozzle 13 is an example of a substrate oxidation unit.

[0106] The oxidant nozzle 13 is a moving nozzle that can move at least in the horizontal direction. The oxidant nozzle 13 is moved horizontally by a second nozzle moving unit 34 having the same configuration as the first nozzle moving unit 33. The oxidant nozzle 13 may be movable in the vertical direction. Different from this embodiment, the oxidant nozzle 13 may be a fixed nozzle with fixed horizontal and vertical positions.

[0107] The oxidant nozzle 13 is connected to one end of an oxidant pipe 44 that guides a liquid oxidant to the oxidant nozzle 13. The other end of the oxidant pipe 44 is connected to an oxidant tank (not shown). An oxidant valve 54A for opening and closing the flow path in the oxidant pipe 44 and an oxidant flow rate adjustment valve 54B for adjusting the flow rate of the liquid oxidant in the flow path are interposed in the oxidant pipe 44.

[0108] When the oxidant valve 54A is opened, the liquid oxidant is discharged continuously downward from the discharge port of the oxidant nozzle 13 at a flow rate corresponding to the opening degree of the oxidant flow rate adjustment valve 54B. FIG. 10 is a flowchart for explaining an example of substrate processing executed by the substrate processing apparatus 1P according to the second embodiment. FIGS. 11A and 11B are schematic diagrams for explaining the state of the substrate W when the substrate processing according to the second embodiment is being performed.

[0109] The main difference between the substrate processing according to the second embodiment shown in FIG. 10 and the substrate processing according to the first embodiment (see FIG. 5) is that after the last first liquid removal step (step S6), a second oxide layer is formed on the surface layer portion of the upper surface of the substrate W, and then the second oxide layer is removed. Hereinafter, mainly with reference to FIGS. 9 and 10, the differences between the substrate processing according to the second embodiment and the substrate processing according to the first embodiment (see FIG. 5) will be described in detail. FIGS. 11A and 11B will be referred to as appropriate.

[0110] Specifically, after the last liquid removal step (step S6), supply of a liquid oxidant (oxidation treatment) is executed on the upper surface of the substrate W (liquid oxidant supply step (oxidation step): step S8). First, the second nozzle moving unit 34 moves the oxidant nozzle 13 to the processing position. The processing position of the oxidant nozzle 13 is, for example, a central position where the oxidant nozzle 13 faces the central region of the upper surface of the substrate W.

[0111] With the oxidizing agent nozzle 13 positioned at the processing position, the oxidizing agent valve 54A is opened. As a result, as shown in Fig. 11A, a liquid oxidizing agent is supplied (ejected) from the oxidizing agent nozzle 13 toward the central region of the upper surface of the substrate W (liquid oxidizing agent supply step, liquid oxidizing agent ejection step). The liquid oxidizing agent supplied to the upper surface of the substrate W spreads over the entire upper surface of the substrate W due to centrifugal force. The liquid oxidizing agent that reaches the peripheral portion of the upper surface of the substrate W is discharged out of the substrate W from the peripheral portion of the upper surface of the substrate W. By supplying the liquid oxidizing agent to the upper surface of the substrate W, an oxide layer is formed on the processing target layer exposed from the upper surface of the substrate W (second oxide layer forming step, wet oxidation step). In this substrate processing, the substrate W can be oxidized by a simple step of supplying the liquid oxidizing agent to the substrate W.

[0112] While supplying the liquid oxidizing agent to the upper surface of the substrate W, the liquid oxidizing agent may be heated through the substrate W using the heater unit 6. Specifically, the heater unit 6 is arranged at a proximity position to heat the rotating substrate W. By heating the liquid oxidizing agent, the formation of the second oxide layer is promoted (second oxide layer formation promotion step). Different from Fig. 11A, during the supply of the liquid oxidizing agent, the heater unit 6 may be arranged at a retracted position or the heater unit 6 may be arranged at a contact position.

[0113] After the supply of the liquid oxidizing agent has continued for a predetermined time, a rinse liquid is supplied to the upper surface of the substrate W, and an oxidizing agent removal process for removing the liquid oxidizing agent from the upper surface of the substrate W is process executed. Specifically, the oxidizing agent valve 54A is closed, and the rinse liquid valve 52A is opened. As a result, the supply of the liquid oxidizing agent to the upper surface of the substrate W is stopped, and instead, the supply (ejection) of the rinse liquid from the rinse liquid nozzle 11 to the upper surface of the substrate W is started (rinse liquid supply step, rinse liquid ejection step). As a result, as shown in Fig. 11B, the liquid oxidizing agent on the substrate W is replaced with the rinse liquid, and the liquid oxidizing agent is removed from the upper surface of the substrate W. In the second embodiment, the rinse liquid also functions as an oxidizing agent removal liquid for removing the liquid oxidizing agent on the upper surface of the substrate W.

[0114] After the oxidizing agent valve 54A is closed, the second nozzle moving unit 34 moves the oxidizing agent nozzle 13 to the retracted position. When the oxidizing agent nozzle 13 is in the retracted position, it does not face the upper surface of the substrate W and is located outside the processing cup 7 in a plan view. Thereafter, a second polymer-containing liquid supply step (step S9), a second polymer film formation step (step S10), a second polymer film heating step (step S11), a second polymer film removal step (step S12), and a second liquid removal step (step S13) are executed.

[0115] The second polymer-containing liquid supply step (step S9), the second polymer film formation step (step S10), the second polymer film heating step (step S11), the second polymer film removal step (step S12), and the second liquid removal step (step S13) are the same processes as the first polymer-containing liquid supply step (step S2), the first polymer film formation step (step S3), the first polymer film heating step (step S4), the first polymer film removal step (step S5), and the first liquid removal step (step S6), respectively, and thus detailed descriptions thereof are omitted.

[0116] Supplementally, in the second polymer film formation step, the substrate W is etched by the polymer film 101 (second polymer film) formed on the substrate W (second etching step), and at least a part of the second oxide layer is removed from the upper surface of the substrate W by the action of the acidic polymer in the polymer film 101 (second oxide layer removal step). Note that the second etching step (second oxide layer removal step) is started by heating the polymer film 101 (second etching start step). Further, in the second polymer film removal step, the main surface of the substrate W is washed with a rinse liquid (second rinse liquid) (second rinse step). The rinse liquid supplied to the upper surface of the substrate W in the second polymer film removal step functions as a second polymer removal liquid.

[0117] Further, the acidic polymer, the alkaline component, and the conductive polymer contained in the second polymer film are examples of a second acidic polymer, a second alkaline component, and a second conductive polymer, respectively. After removing the rinse liquid from the upper surface of the substrate W, the formation and removal of the second oxide layer may be performed again. That is, after the second polymer film removal step (strictly speaking, the second liquid removal step), the liquid oxidant supply step (oxidation step), the second polymer film formation step (second etching step), and the second polymer film removal step (second rinse step) may be further performed at least once each in this order. More specifically, the cycle process from the liquid oxidant supply step (step S8) to the second liquid removal step (step S13) (hereinafter sometimes referred to as the "second cycle process") may be performed two or more times.

[0118] In FIG. 10, "M" means an integer of 0 or more. Therefore, the liquid oxidant supply step (step S8) to the second liquid removal step (step S13) are each performed once, and when "M" is 1 or more, the liquid oxidant supply step (step S8) to the second liquid removal step (step S13) are performed two or more times. That is, when "M" is 1 or more, the second cycle process is performed a plurality of times.

[0119] When "M" is 1 or more, the liquid oxidant supply step (second oxide layer formation step) and the second polymer film formation step (second oxide layer removal step) are alternately repeated. In other words, the liquid oxidant supply step (second oxide layer formation step) and the second polymer film formation step (second oxide layer removal step) are alternately performed a plurality of times each. After the last second liquid removal step (step S13), the spin motor 23 stops the rotation of the substrate W. The transfer robot CR enters the wet processing unit 2W, receives the processed substrate W from the plurality of chuck pins 20, and carries it out of the wet processing unit 2W (substrate carry-out step: step S7). The substrate W is passed from the transfer robot CR to the transfer robot IR and stored in the carrier C by the transfer robot IR.

[0120] FIG. 12 is a schematic diagram for explaining the change in the surface layer portion of the upper surface of the substrate W due to the repeated alternation of the oxidation step and the second etching step in the substrate processing according to the second embodiment. As shown in FIGS. 12(a) and 12(b), a second oxide layer 106 is formed on the surface layer portion of the layer 102 to be processed by supplying a liquid oxidant such as hydrogen peroxide water to the upper surface of the substrate W (second oxide layer forming step). Thereafter, a polymer-containing liquid is supplied to the upper surface of the substrate W, and at least a part of the solvent in the polymer-containing liquid on the substrate W is evaporated, whereby a polymer film 101 (second polymer film) is formed on the upper surface of the substrate W as shown in FIG. 12(c) (second polymer film forming step). Thereafter, as shown in FIG. 12(d), by heating the polymer film 101, the alkali component evaporates and the alkali component is removed from the polymer film 101 (alkali component evaporation step, alkali component removal step). By the action of the acidic polymer in the polymer film 101 on the upper surface of the substrate W, the second oxide layer 106 is dissolved and dissolved in the polymer film 101. Thereby, as shown in FIG. 12(e), the second oxide layer 106 is selectively removed from the upper surface of the substrate W (second oxide layer removal step). FIG. 12(f) shows the state of the surface of the layer 102 to be processed after the polymer film 101 has been removed thereafter.

[0121] By executing the oxidation step (second oxide layer forming step) and the second etching step (second oxide layer removal step) once each, the thickness of the layer 102 to be oxidized is substantially constant (see FIG. 12(b)). Therefore, the thickness (etching amount D1) of the second oxide layer 106 to be etched is also substantially constant (see FIG. 12(e)). As shown in FIG. 12(f), by executing the second cycle process a plurality of cycles, in the layer 102 to be processed, a portion having a thickness D2 corresponding to the product of the etching amount D1 and the number of cycles (3 cycles in FIG. 12(h)) is etched (removed) from the substrate W (D2 = D1 x number of cycles). The amount of the layer 102 to be processed etched by performing the second cycle process a plurality of cycles corresponds to the thickness D2. Therefore, by adjusting the number of times of repeatedly executing the oxidation step (second oxide layer forming step) and the second etching step (second oxide layer removal step), a desired etching amount (the same amount as the thickness D2) can be achieved.

[0122] Etching the processing target layer 102 step by step with a certain etching amount in this way is called digital etching. Also, etching the processing target layer 102 (the surface layer part on the upper surface of the substrate W) by repeatedly executing the second oxide layer forming step and the second oxide layer removing step is called cycle etching. According to the second embodiment, the same effects as those of the first embodiment are achieved. According to the second embodiment, the following further effects are achieved.

[0123] According to the second embodiment, after the last first rinsing step, an oxidation treatment is performed on the upper surface of the substrate W, and then the substrate W is etched. Therefore, the substrate W can be additionally etched to ensure a sufficient etching amount. Therefore, the substrate W can be etched better. Specifically, after the first oxide layer 103 (see FIG. 1) is removed, a second oxide layer 106 is formed on the surface layer part of the surface of the processing target layer 102. Then, after the oxidation treatment, the second oxide layer 106 is removed from above the processing target layer 102 by forming and removing the polymer film 101. That is, both the pre-formed first oxide layer 103 and the second oxide layer 106 formed by the second oxide layer forming step are removed. Therefore, when the etching amount of the substrate W is insufficient only by removing the first oxide layer 103, the processing target layer 102 is oxidized to additionally form the second oxide layer 106, and by removing the second oxide layer 106, a sufficient etching amount can be ensured.

[0124] Also, when removing the second oxide layer 106, the polymer film 101 is used in the same manner as when removing the first oxide layer 103. Therefore, the usage amount of the substance required for etching the substrate W can be reduced. Also, when the second cycle process is executed multiple times in the second embodiment, after the second rinse step, the oxidation step, the second etching step, and the second rinse step are each further executed at least once in this order. That is, the formation and removal of the second oxide layer 106 are alternately executed multiple times. Therefore, it is possible to repeat the formation and removal of a small amount of the second oxide layer 106 (for example, 1 nm or more and 10 nm or less). Therefore, compared with the case where a large amount of the second oxide layer 106 is formed and removed at once, it is easier to adjust the etching amount of the substrate W. As a result, the substrate W can be etched with high precision.

[0125] Also, according to the second embodiment, by heating the polymer film 101 formed in the second polymer film forming step to evaporate the alkaline component, the acidic polymer in the polymer film 101 regains its activity and etching is started. Therefore, the substrate W can be etched with high precision. In particular, the start timing of etching the substrate W can be accurately controlled. Also, according to the first embodiment, in the second etching step as well, the action of the conductive polymer can promote the ionization of the acidic polymer in the polymer film 101. Therefore, the acidic polymer can effectively act on the first oxide layer 103.

[0126] <Other Embodiments> The present invention is not limited to the embodiments described above, and can be implemented in other forms. The polymer-containing liquid contains, as solutes, an acidic polymer, an alkaline component, and a conductive polymer. However, the polymer-containing liquid may not contain an alkaline component and a conductive polymer. The polymer-containing liquid may contain only one of an alkaline component and a conductive polymer in addition to the acidic polymer as a solute.

[0127] The means for heating the polymer film 101 is not limited to the heater unit 6. For example, although not shown, the means for heating the polymer film 101 may be a heater facing the upper surface of the substrate W. Further, as shown in FIG. 13, the means for heating the polymer film 101 may be configured to heat the polymer film 101 via the substrate W by supplying a heating fluid from a heating fluid nozzle 14 facing the lower surface of the substrate W to the lower surface of the substrate W.

[0128] The heating fluid discharged from the heating fluid nozzle 14 is, for example, high-temperature DIW having a temperature higher than room temperature and lower than the boiling point of the solvent contained in the polymer-containing liquid. When the solvent contained in the polymer-containing liquid is DIW, as the heating fluid, for example, DIW of 60°C or higher and lower than 100°C is used. The heating fluid discharged from the heating fluid nozzle 14 is not limited to high-temperature DIW, and may be a high-temperature gas such as high-temperature inert gas or high-temperature air having a temperature higher than room temperature and lower than the boiling point of the solvent contained in the polymer-containing liquid.

[0129] The heating fluid nozzle 14 is inserted into, for example, the through hole 21a of the spin base 21. The discharge port 14a of the heating fluid nozzle 14 faces the central region of the lower surface of the substrate W from below. The heating fluid nozzle 14 is connected to a heating fluid pipe 45 that guides the heating fluid to the heating fluid nozzle 14. The heating fluid pipe 45 is interposed with a heating fluid valve 55A that opens and closes the flow path in the heating fluid pipe 45 and a heating fluid flow rate adjustment valve 55B that adjusts the flow rate of the heating fluid in the heating fluid pipe 45. A heater 55C (temperature adjustment unit) for adjusting the temperature of the heating fluid supplied to the heating fluid nozzle 14 may be provided.

[0130] Further, in the first polymer film heating step (step S4) of each of the above-described embodiments, heating of the polymer film 101 may be started in a state where the atmosphere in contact with the substrate W is replaced with an inert gas such as nitrogen gas. Thereby, it is possible to suppress the formation of an unintended oxide layer after the removal of the first oxide layer 103. Similarly, in the second polymer film heating step (step S11), heating of the polymer film 101 may be started in a state where the atmosphere in contact with the substrate W is replaced with an inert gas such as nitrogen gas.

[0131] Further, the spin chuck 5 is not limited to a gripping type, and for example, although not shown, it may be a vacuum chuck of a vacuum adsorption type. The vacuum chuck holds the substrate W in a horizontal posture at the holding position by vacuum-adsorbing the back surface of the substrate W, and further rotates the substrate W held by the spin chuck 5 by rotating it around a vertical rotation axis in that state.

[0132] Also, in the above-described embodiment, after supplying the polymer-containing liquid onto the upper surface of the substrate W, the solvent is evaporated from these liquids to form the polymer film 101 on the upper surface of the substrate W. However, different from the above-described embodiment, the polymer film 101 may be formed on the upper surface of the substrate W by applying a semi-solid polymer film 101 onto the upper surface of the substrate W. Further, the surface layer portion of the main surface of the substrate W used for the substrate processing according to the above-described embodiment does not have to have the structure shown in FIG. 1. For example, the processing target layer 102 may be exposed from the entire main surface of the substrate W, or the concavo-convex pattern 120 may not be formed. Further, the processing target layer 102 does not have to be composed of a single substance, and may be composed of a plurality of substances.

[0133] Also, in the substrate processing according to the above-described first embodiment (see FIG. 5), the first polymer film heating step (step S4) may be appropriately omitted. Further, in the first liquid removal step (step S6) of the substrate processing according to the above-described first embodiment, the rinse liquid can be removed from the upper surface of the substrate W by stopping the supply of the rinse liquid without accelerating the rotation of the substrate W. In this case, the rinse liquid is not removed to the extent that the upper surface of the substrate W dries, and a small amount of the rinse liquid remains on the upper surface of the substrate W, but the acceleration of the rotation of the substrate W can be omitted, so that the time required for the substrate processing can be reduced.

[0134] However, in the last first liquid removal step (step S6), it is preferable to accelerate the rotation of the substrate W to the drying speed. If so, the substrate W can be carried out of the wet processing unit 2W with the upper surface of the substrate W sufficiently dried. Similarly, in the substrate processing according to the above-described second embodiment (see FIG. 10), the first polymer film heating step (step S4) and the second polymer film heating step (step S11 ) may be appropriately omitted. Further, in the first liquid removal step (step S6) and the second liquid removal step (step S13) of the substrate processing according to the above-described second embodiment, the rinse liquid may be removed from the upper surface of the substrate W by stopping the supply of the rinse liquid without accelerating the rotation of the substrate W. In this case, the rinse liquid is not removed to the extent that the upper surface of the substrate W dries, and a small amount of the rinse liquid remains on the upper surface of the substrate W, but the acceleration of the rotation of the substrate W can be omitted, so that the time required for the substrate processing can be reduced.

[0135] However, in the last second liquid removal step (step S13), it is preferable to accelerate the rotation of the substrate W to the drying speed. If so, the substrate W can be carried out of the wet processing unit 2W with the upper surface of the substrate W sufficiently dried. Also, in the substrate processing according to the second embodiment (see FIG. 10), a second oxide layer is formed by supplying a liquid oxidant. That is, as the oxidation treatment, the supply of the liquid oxidant is performed. However, the oxidation treatment is not limited to the supply of the liquid oxidant, and the second oxide layer may be formed by a dry oxidation process that does not use a liquid. The dry oxidation process may be formed by, for example, light irradiation (for example, UV irradiation), heating, a gaseous oxidant, or the like. The gaseous oxidant is, for example, a gaseous oxidant such as ozone gas.

[0136] Also, in the above-described second embodiment, when the second oxide layer 106 is not completely removed by forming the polymer film 101 once, after the second liquid removal step (step S13), instead of returning to the oxidation step (step S8), it may return to the second polymer-containing liquid supply step (step S9) (see the two-dot chain line in FIG. 10). That is, the second liquid removal step (step S13) may be further executed one by one from the second polymer-containing liquid supply step (step S9).

[0137] In other words, after the oxidation step, the second polymer film forming step and the second polymer film-containing liquid supply step are further executed at least once in this order. Since the second etching step is further executed after the second polymer film removal step, the polymer film 101 formed on the upper surface of the substrate W is once removed, and the polymer film 101 is formed again on the upper surface of the substrate. Therefore, the polymer film 101 in which the acidic polymer has been consumed by removing the second oxide layer 106 can be removed from the upper surface of the substrate W, and the second oxide layer 106 can be removed by the new polymer film 101. Therefore, even when the second oxide layer 106 is not etched by a desired amount by forming and removing the polymer film 101 once, the second oxide layer 106 can be sufficiently etched by performing the formation and removal of the polymer film 101 a plurality of times. For example, the second oxide layer 106 may be completely removed from the substrate W by forming and removing the polymer film 101 a plurality of times.

[0138] In the second embodiment, the acidic polymers in the first polymer film formed on the upper surface of the substrate W in the first polymer film forming step and the acidic polymers in the second polymer film formed on the upper surface of the substrate W in the second polymer film forming step may be different substances from each other. In the above-described embodiment, the removal of the first polymer film and the second polymer film is performed by supplying a rinsing liquid. However, unlike the above-described embodiment, the first polymer film and the second polymer film may be removed by plasma treatment or light irradiation treatment such as irradiation with light such as UV.

[0139] Also, each component in the first polymer film (first acidic polymer, first alkaline component, first conductive polymer) and the corresponding components in the second polymer film (second acidic polymer, second alkaline component, second conductive polymer) may be different from each other. In that case, it is necessary to prepare a polymer-containing liquid for forming the first polymer film and a polymer-containing liquid for forming the second polymer film, respectively.

[0140] In each of the above-described embodiments, substrate processing including etching by the polymer film 101 is performed on the upper surface of the substrate W. However, unlike the above-described embodiment, substrate processing may be performed on the lower surface of the substrate W. In the above-described embodiment, the substrate processing apparatuses 1 and 1P include transfer robots IR and CR, a plurality of processing units 2, and a controller 3. However, the substrate processing apparatuses 1 and 1P may be configured by a single processing unit 2 and a controller 3 and may not include the transfer robots IR and CR. Alternatively, the substrate processing apparatus 1 may be configured by only a single processing unit 2. In other words, the processing unit 2 may be an example of the substrate processing apparatus.

[0141] In each of the above-described embodiments, each configuration may be schematically shown in blocks, but the shape, size, and positional relationship of each block do not indicate the shape, size, and positional relationship of each configuration. Note that in the above-described embodiment, expressions such as "along", "horizontal", and "vertical" are used. It is not necessary for it to be strictly "along", "horizontal", or "vertical". That is, each of these expressions allows for deviations in manufacturing accuracy, installation accuracy, etc.

[0142] In addition, various modifications can be made within the scope described in the claims.

Explanation of Reference Numerals

[0143] 1: Substrate processing apparatus 1P: Substrate processing apparatus 2: Processing unit (substrate processing apparatus) 10: Polymer-containing liquid nozzle (polymer film forming unit) 11: Rinse liquid nozzle (polymer removal liquid supply unit) 101: Polymer film (first polymer film, second polymer film) 102: Layer to be processed (surface layer portion of the main surface of the substrate) 103: First oxide layer 106: Second oxide layer 115: Acidic polymer W: Substrate

Claims

1. A substrate preparation step of preparing a substrate having a main surface on which a first oxide layer is exposed, a first etching step of forming a first polymer film containing a first acidic polymer on the main surface of the substrate and etching the substrate, and a first rinsing step of supplying a first rinsing liquid for cleaning the main surface of the substrate to the main surface of the substrate after the first etching step, wherein in the first etching step, a fluorine-containing etching liquid is not used, a substrate processing method.

2. A substrate preparation step of preparing a substrate having a main surface on which a first oxide layer is exposed, a first etching step of forming a first polymer film containing a first acidic polymer on the main surface of the substrate and etching the substrate, and a first rinsing step of supplying a first rinsing liquid for cleaning the main surface of the substrate to the main surface of the substrate after the first etching step, wherein the first polymer film contains a solvent, a substrate processing method.

3. A substrate preparation step of preparing a substrate having a main surface on which a first oxide layer is exposed, a first etching step of forming a first polymer film containing a first acidic polymer on the main surface of the substrate and etching the substrate, and a first rinsing step of supplying a first rinsing liquid for cleaning the main surface of the substrate to the main surface of the substrate after the first etching step, wherein the first polymer film further contains a first alkaline component, and the first etching step includes a first etching start step of heating the first polymer film after the first polymer film is formed to evaporate the first alkaline component from the first polymer film to start etching of the substrate, a substrate processing method.

4. The substrate processing method according to any one of Claims 1 to 3, wherein the first polymer film further contains a first conductive polymer.

5. A substrate preparation step of preparing a substrate having a main surface on which a first oxide layer is exposed, a first etching step of forming a first polymer film containing a first acidic polymer and a first conductive polymer on the main surface of the substrate and etching the substrate, and a first rinsing step of supplying a first rinsing liquid for cleaning the main surface of the substrate to the main surface of the substrate after the first etching step, a substrate processing method.

6. The first etching step includes a first oxide layer removal step of removing at least a part of the first oxide layer by the first acidic polymer in the first polymer film, The substrate processing method according to any one of claims 1 to 5, wherein the first rinsing step includes a first polymer film removing step of removing the first polymer film from the main surface of the substrate with the first rinsing liquid.

7. The substrate processing method according to any one of claims 1 to 6, wherein after the first rinsing step, the first etching step and the first rinsing step are further executed at least once each in this order.

8. The substrate processing method according to claim 7, further including a first liquid removing step of removing the first rinsing liquid from the main surface of the substrate after the first rinsing step and before the next first etching step is started.

9. Before the first etching step, the method further includes a polymer-containing liquid supply step of supplying a polymer-containing liquid containing a solvent and the first acidic polymer to the main surface of the substrate. The substrate processing method according to any one of claims 1 to 8, wherein the first etching step includes a step of forming the first polymer film by evaporating at least a part of the solvent in the polymer-containing liquid on the main surface of the substrate.

10. After the last first rinsing step, an oxidation step of performing an oxidation treatment on the main surface of the substrate. After the oxidation step, a second etching step of forming a semi-solid or solid second polymer film containing a second acidic polymer on the main surface of the substrate and etching the substrate. The substrate processing method according to any one of claims 1 to 9, further including a second rinsing step of supplying a second rinsing liquid to the main surface of the substrate after the second etching step.

11. A substrate preparation step of preparing a substrate having a main surface on which a first oxide layer is exposed. A first etching step of forming a first polymer film containing a first acidic polymer on the main surface of the substrate and etching the substrate. A first rinsing step of supplying a first rinsing liquid for cleaning the main surface of the substrate to the main surface of the substrate after the first etching step. After the last first rinsing step, an oxidation step of performing an oxidation treatment on the main surface of the substrate. After the oxidation step, a second etching step of forming a semi-solid or solid second polymer film containing a second acidic polymer on the main surface of the substrate and etching the substrate. A substrate processing method including a second rinsing step of supplying a second rinsing liquid to the main surface of the substrate after the second etching step.

12. The second polymer film further contains a second alkali component, The substrate processing method according to claim 10 or 11, wherein the second etching step includes a second etching start step of heating the second polymer film after the second polymer film is formed to evaporate the second alkali component from the second polymer film to start etching of the substrate.

13. The substrate processing method according to any one of claims 10 to 12, wherein the second polymer film further contains a second conductive polymer.

14. The oxidation step includes a second oxide layer forming step of forming a second oxide layer on the surface layer portion of the main surface of the substrate, The second etching step includes a second oxide layer removing step of removing at least a part of the second oxide layer by the second acidic polymer in the second polymer film, The substrate processing method according to any one of claims 10 to 13, wherein the second rinse step includes a second polymer film removing step of removing the second polymer film from the main surface of the substrate with the second rinse liquid after the second etching step.

15. The substrate processing method according to any one of claims 10 to 14, wherein after the second rinse step, the oxidation step, the second etching step, and the second rinse step are further executed at least once in this order.

16. The substrate processing method according to any one of claims 1 to 15, wherein the first acidic polymer is a carboxy group-containing polymer, a sulfo group-containing polymer, or a mixture thereof.

17. A substrate processing apparatus for etching a substrate having a main surface on which an oxide layer is exposed, A polymer film forming unit that forms a polymer film containing an acidic polymer on the main surface of the substrate, A rinse liquid supply unit that supplies a rinse liquid for cleaning the main surface of the substrate to the main surface of the substrate, An etching step of forming a polymer film on the main surface of the substrate by the polymer film forming unit to etch the substrate, After the etching step, a rinse step of supplying a rinse liquid to the main surface of the substrate by the rinse liquid supply unit to clean the main surface of the substrate is executed, A substrate processing apparatus that does not use a fluorine-containing etching liquid in the etching step.

18. A substrate processing apparatus for etching a substrate having a main surface on which an oxide layer is exposed, A polymer film forming unit that forms a polymer film containing an acidic polymer on the main surface of the substrate; A rinse liquid supply unit that supplies a rinse liquid for cleaning the main surface of the substrate to the main surface of the substrate, and includes: An etching step of forming a polymer film on the main surface of the substrate by the polymer film forming unit and etching the substrate; After the etching step, a rinse step of supplying a rinse liquid to the main surface of the substrate by the rinse liquid supply unit to clean the main surface of the substrate is executed. The substrate processing apparatus, wherein the polymer film contains a solvent. A substrate processing apparatus, wherein the polymer film contains a solvent. **Claim 19**: A substrate processing apparatus for etching a substrate having a main surface on which an oxide layer is exposed, comprising: A polymer film forming unit that forms a polymer film containing an acidic polymer and an alkali component on the main surface of the substrate; A heating unit that heats the polymer film formed on the main surface of the substrate; A rinse liquid supply unit that supplies a rinse liquid for cleaning the main surface of the substrate to the main surface of the substrate, and includes: An etching step of forming a polymer film on the main surface of the substrate by the polymer film forming unit, and after the polymer film is formed, heating the polymer film by the heating unit to evaporate the alkali component from the polymer film to start etching the substrate. The substrate processing apparatus further includes an etching step of etching the substrate, and after the etching step, a rinse step of supplying a rinse liquid to the main surface of the substrate by the rinse liquid supply unit to clean the main surface of the substrate. A substrate processing apparatus that executes, after the etching step, a rinse step of supplying a rinse liquid to the main surface of the substrate by the rinse liquid supply unit to clean the main surface of the substrate. **Claim 20**: A substrate processing apparatus for etching a substrate having a main surface on which an oxide layer is exposed, comprising: A polymer film forming unit that forms a polymer film containing an acidic polymer and a conductive polymer on the main surface of the substrate; A rinse liquid supply unit that supplies a rinse liquid for cleaning the main surface of the substrate to the main surface of the substrate, and includes: An etching step of forming a polymer film on the main surface of the substrate by the polymer film forming unit and etching the substrate; A substrate processing apparatus that executes, after the etching step, a rinse step of supplying a rinse liquid to the main surface of the substrate by the rinse liquid supply unit to clean the main surface of the substrate. **Claim 21**: A substrate processing apparatus for etching a substrate having a main surface on which an oxide layer is exposed, comprising: A first polymer film forming unit that forms a first polymer film containing a first acidic polymer on the main surface of the substrate; A first rinse liquid supply unit that supplies a first rinse liquid for cleaning the main surface of the substrate to the main surface of the substrate; An oxidation unit that performs an oxidation treatment on the main surface of the substrate; A second polymer film forming unit that forms a semi-solid or solid second polymer film containing a second acidic polymer on the main surface of the substrate; A second rinse liquid supply unit that supplies a second rinse liquid for cleaning the main surface of the substrate to the main surface of the substrate, and includes: A first etching step of forming the first polymer film on the main surface of the substrate by the first polymer film forming unit and etching the substrate; After the first etching step, a first rinse step of supplying the first rinse liquid to the main surface of the substrate by the first rinse liquid supply unit to clean the main surface of the substrate; After the last first rinse step, an oxidation step of performing an oxidation treatment on the main surface of the substrate by the oxidation unit; After the oxidation step, a second etching step of forming the second polymer film on the main surface of the substrate by the second polymer film forming unit and etching the substrate; A substrate processing apparatus that performs a second rinse step of supplying the second rinse liquid to the main surface of the substrate by the second rinse liquid supply unit after the second etching step.

Images