Substrate processing method and substrate processing device

Abstract

The present invention provides a technology that can reduce the incidence of etching defects with a simple structure. The substrate processing method of the present invention includes a substrate holding process, a charging process, and an etching liquid supply process. In the substrate holding process, the substrate is held by a substrate holding portion. In the charging process, the substrate is rotated around a rotation axis passing through the central portion of the substrate, and a first mixed liquid obtained by mixing pure water and an additive gas at a first mixed concentration that can make the entire first main surface of the substrate positively charged is supplied to the substrate to charge the substrate. In the etching liquid supply process, after the charging process or in parallel with the charging process, the substrate is rotated around the rotation axis, and the etching liquid is supplied to the first main surface of the substrate.

Description

Technical Field

[0001] The present application relates to a substrate processing method and a substrate processing device. Background Art

[0002] In the past, a substrate processing device has been proposed, which supplies an acidic or alkaline etching solution to the surface of a silicon substrate to etch the surface. For example, an etching object (a semiconductor layer such as silicon or an insulating layer such as silicon oxide) and a resist pattern are formed on the surface of the substrate, and the etching device etches the etching object.

[0003] If an acidic or alkaline etching solution is supplied to the surface of the substrate, the surface of the substrate is negatively charged through the electric double layer. As a result, the sidewalls of the pattern are also negatively charged. The charge of the sidewalls of the pattern is near the sidewalls of the pattern, and repels the negative ions in the etching solution. The narrower the gap between the patterns, the more the charge of the sidewalls of the pattern will affect the entire gap, so it is difficult for the etching solution to enter the gap. As a result, there is a problem of poor etching.

[0004] Therefore, a technology is proposed for suppressing poor etching by applying voltage to the substrate so that the surface of the substrate is charged with opposite polarity. As such an etching device, for example, the structure of the substrate processing device described in Patent Document 1 can be adopted. The substrate processing device includes a substrate holding mechanism, an etching liquid supply mechanism, and a control device for controlling a plurality of electrodes. The control device performs: an etching process, while rotating the substrate around a rotation axis, while supplying etching liquid to the substrate; and an etching charging process, applying voltage to a plurality of electrodes in a manner such that the absolute value of the applied voltage increases in the order of the first electrode and the second electrode, thereby charging the substrate in parallel with the etching process.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2016-184701 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, the substrate processing apparatus described in Patent Document 1 requires various mechanisms (eg, a first electrode and a second electrode) for applying a voltage to the substrate, which complicates the substrate processing apparatus.

[0010] Therefore, an object of the present application is to provide a technology capable of reducing the occurrence rate of etching defects with a simple structure.

[0011] Means used to solve problems

[0012] The first mode of the substrate processing method comprises: a substrate holding process, in which the substrate is held by a substrate holding portion; a charging process, in which the substrate is rotated around a rotation axis passing through the central portion of the substrate, and a first mixed liquid obtained by mixing pure water and an additive gas with a first mixed concentration that can make the entire surface of the first main surface of the substrate positively charged is supplied to the substrate to charge the substrate; and an etching liquid supplying process, in which the substrate is rotated around the rotation axis after the charging process or in parallel with the charging process, and the etching liquid is supplied to the first main surface of the substrate.

[0013] A second aspect of the substrate processing method is the substrate processing method according to the first aspect, wherein the first mixed concentration is a value determined based on a charge distribution on the substrate.

[0014] The third mode of the substrate processing method is a substrate processing method as described in the first or second mode, wherein, in the above-mentioned charging process, the above-mentioned first mixed liquid is supplied to the second main surface of the above-mentioned substrate opposite to the above-mentioned first main surface, and the above-mentioned substrate processing method also has a static elimination process, in which, after the above-mentioned etching liquid supplying process, the second mixed liquid with a concentration of added gas higher than the above-mentioned first mixed concentration is supplied to the above-mentioned second main surface of the above-mentioned substrate to eliminate static electricity from the above-mentioned substrate.

[0015] The fourth method of the substrate processing method is a substrate processing method as described in any one of the first to third methods, wherein the method further comprises a rinsing liquid supplying process, wherein, after the above-mentioned etching liquid supplying process, the rinsing liquid supplying process supplies pure water, or a third mixed liquid obtained by mixing pure water and an additive gas with a third mixed concentration different from the above-mentioned first mixed concentration, to the above-mentioned first main surface of the above-mentioned substrate.

[0016] A fifth aspect of the substrate processing method is the substrate processing method according to the fourth aspect, wherein a concentration of the additional gas in the third mixed concentration is greater than a concentration of the additional gas in the first mixed concentration.

[0017] A sixth aspect of the substrate processing method is the substrate processing method as described in any one of the first to fifth aspects, wherein the additional gas is carbon dioxide.

[0018] The 7th method of substrate processing is a substrate processing method as described in any one of the 1st to 6th methods, wherein, in the above-mentioned charging process, the above-mentioned substrate is rotated at a first rotation speed, and in the above-mentioned etching liquid supplying process, the above-mentioned substrate is rotated at a second rotation speed lower than the above-mentioned first rotation speed.

[0019] The eighth aspect of the substrate processing method is the substrate processing method as described in the seventh aspect, wherein, in the etching liquid supplying step, after rotating the substrate at the second rotation speed, the substrate is rotated at a third rotation speed lower than the second rotation speed.

[0020] A ninth aspect of the substrate processing method is the substrate processing method as described in any one of the first to eighth aspects, wherein the etching liquid supplying step is performed after the charging step is completed.

[0021] The tenth method of the substrate processing method is a substrate processing method as described in any one of the first to eighth methods, wherein, in the above-mentioned charging process, the above-mentioned first mixed liquid is supplied to the second main surface of the above-mentioned substrate opposite to the above-mentioned first main surface, and the above-mentioned charging process and the above-mentioned etching liquid supply process are performed in parallel.

[0022] An eleventh aspect of the substrate processing method is the substrate processing method according to the tenth aspect, wherein the charging step is started before the etching liquid supplying step is started.

[0023] A twelfth aspect of the substrate processing method is the substrate processing method according to the tenth aspect, wherein the charging step is started after starting the etching liquid supplying step.

[0024] The substrate processing device comprises: a substrate holding portion, which holds the substrate and rotates the substrate around a rotation axis passing through the central portion of the substrate; a mixed liquid supply portion, which supplies a first mixed liquid obtained by mixing pure water and an additive gas at a first mixed concentration so that the entire first main surface of the substrate held by the substrate holding portion is positively charged to the substrate, so as to charge the substrate; and an etching liquid supply portion, which supplies etching liquid to the first main surface of the substrate held by the substrate holding portion.

[0025] Effects of the Invention

[0026] According to the first and sixth modes of the substrate processing method and the mode of the substrate processing apparatus, the first main surface of the substrate is positively charged, so even if the gap (groove) or hole between the patterns formed on the first main surface is small, the etching liquid can easily enter the gap or the hole. As a result, the occurrence rate of etching defects can be reduced. In addition, since there is no need for an electrode to charge the substrate, the apparatus can be simply constructed.

[0027] According to the second aspect of the substrate processing method, the first mixed concentration can be appropriately determined.

[0028] According to the third aspect of the substrate processing method, the concentration of the added gas is high, so the static electricity of the substrate can be quickly eliminated.

[0029] According to the fourth aspect of the substrate processing method, the etching liquid can be rinsed away by the rinse liquid supplying step.

[0030] According to the fifth aspect of the substrate processing method, the concentration of the added gas in the third mixed liquid used in the rinsing liquid supply process is greater than that in the first mixed liquid used in the charging process, so that in the rinsing liquid supply process, the substrate can be charged while the etching liquid can be rinsed. In other words, the concentration of the added gas in the first mixed liquid in the charging process is less than that in the third mixed liquid, so the amount of charge on the substrate in the charging process can be increased.

[0031] According to the seventh aspect of the substrate processing method, the first rotation speed in the charging process is high, so the charge amount of the substrate generated by the friction between the first mixed liquid and the first main surface of the substrate can be increased, or the charging speed can be increased.

[0032] According to the eighth aspect of the substrate processing method, the initial second rotation speed of the etching liquid supply process is higher than the subsequent third rotation speed, so that the etching liquid can be quickly spread over the entire first main surface of the substrate in the initial stage. In addition, the third rotation speed is relatively low, so the fluidity of the etching liquid becomes lower after the etching liquid spreads over the entire surface of the substrate, and the etching of the substrate can be appropriately performed.

[0033] According to the ninth aspect of the substrate processing method, the consumption of the first mixed liquid can be reduced.

[0034] According to the tenth aspect of the substrate processing method, the first mixed liquid is also ejected in the etching liquid supplying step. This allows the second main surface of the substrate to be continuously charged. Furthermore, the charging of the first main surface of the substrate can be more easily maintained.

[0035] In addition, the etching liquid scatters from the periphery of the first main surface of the substrate, and the first mixed liquid scatters from the periphery of the second main surface of the substrate. This can prevent the etching liquid from flowing back to the second main surface via the end surface connecting the first main surface and the second main surface.

[0036] According to the eleventh aspect of the substrate processing method, supply of the etching liquid can be started while the substrate is charged.

[0037] According to the twelfth aspect of the substrate processing method, the consumption of the first mixed liquid can be reduced.

[0038] The objects, features, aspects, and advantages of the technology disclosed in this specification will become more apparent from the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a diagram schematically showing an example of the configuration of a substrate processing apparatus.

[0040] Figure 2 This is a diagram schematically showing an example of the structure of the upper surface side of the substrate.

[0041] Figure 3 This is a diagram schematically showing an example of charge distribution on a substrate.

[0042] Figure 4 It is a cross-sectional view schematically showing an example of the structure of the substrate.

[0043] Figure 5 This is a flowchart showing an example of the operation of the substrate processing apparatus.

[0044] Figure 6 This is a diagram schematically showing an example of changes in the rotation speed.

[0045] Figure 7 This is a diagram showing an example of the timing of the charging step and the etching liquid treatment step.

[0046] Figure 8 This is a diagram showing another example of the timing of the charging step and the etching liquid treatment step. DETAILED DESCRIPTION

[0047] Below, refer to the attached Figure 1 The following description will be given in view of the embodiments. In addition, the drawings are schematic diagrams, and for the convenience of description, the configurations are appropriately omitted or simplified. In addition, the size and position of the configurations shown in the drawings may not be accurately described and may be appropriately changed.

[0048] In the following description, the same components are denoted by the same reference numerals and shown in the figures, and their names and functions are also assumed to be the same. Therefore, in order to avoid duplication, their detailed description may be omitted.

[0049] <Overview of substrate processing apparatus>

[0050] Figure 1 1 is a diagram schematically showing an example of the structure of the substrate processing apparatus 100. The substrate processing apparatus 100 supplies an etching liquid to the surface of the substrate W1 to etch the surface of the substrate W1. The substrate W1 is, for example, a semiconductor substrate, and a silicon semiconductor substrate can be used as a more specific example. The substrate W1 has a substantially disk shape.

[0051] The substrate processing apparatus 100 can also remove the metal film or oxide film on the surface of the substrate W1 by etching, for example, as a cleaning process for the substrate W1. On the surface of the substrate W1, deep holes or grooves are formed as a pattern, and the size of the deep holes or grooves is less than 10 [nm] (for example, ), the etching solution is difficult to enter due to the charge on the surface of the substrate W1 caused by the electric double layer.

[0052] Alternatively, the substrate processing apparatus 100 may also etch the surface of the substrate W1 as a pattern forming process rather than a cleaning process. Various layers are formed on the surface of the substrate W1. More specifically, at least one of a resist layer, an insulating layer (e.g., an oxide layer or a nitride layer), a semiconductor layer (e.g., a polysilicon layer or an oxide semiconductor layer), and a metal layer is formed. These layers form a pattern.

[0053] For example, a resist pattern as a resist layer is formed on the top layer of the substrate W1, and an etching object is formed on the lower layer. The etching object is at least one of a metal layer, an insulating layer, and a semiconductor layer. The substrate processing device 100 can also supply an etching liquid to the surface of the substrate W1 to etch the etching object in the lower layer.

[0054] In this embodiment, the gap between the resist patterns formed on the surface of the substrate W1 is, for example, less than 10 [nm], for example It is also difficult for etching liquid to enter the gaps of such narrow pattern.

[0055] Alternatively, the substrate processing apparatus 100 may also etch the substrate W1 described below. Figure 2 This is a diagram schematically showing an example of a pattern on the upper surface of the substrate W1. Figure 2 In the example, a pattern for manufacturing a three-dimensional flash memory (e.g., a 3D NAND flash memory) is formed on the surface of the substrate W1. On the upper surface of the substrate W1, a stacked body is formed in which semiconductor layers 1A (e.g., polysilicon layers) and insulating layers 1B are alternately stacked. The substrate processing device 100 can also supply an etching liquid to the surface of the substrate W1, and etch each insulating layer 1B in a horizontal direction on the side of the stacked body. In this case, the etching object is the insulating layer 1B, and the area sandwiched by the semiconductor layer 1A is equivalent to the gap between the patterns. The etching liquid enters the gap between the patterns and etches the insulating layer 1B.

[0056] Figure 2 In the example of , the etching liquid must enter between the stacked bodies and must enter between the semiconductor layers 1A. Even if the interval p1 between the stacked bodies is narrow or the interval P2 between the semiconductor layers 1A (i.e., the thickness of the insulating layer 1B) is narrow, the etching liquid has difficulty entering these gaps.

[0057] In the present embodiment, a substrate processing apparatus 100 is provided in which an etching liquid can enter into gaps (or holes or grooves) of narrow patterns.

[0058] <Construction of substrate holding device>

[0059] Reference Figure 1 The substrate processing apparatus 100 includes a substrate holding unit 2 , a mixed liquid supply unit 3 , an etching liquid supply unit 4 , and a control unit 5 .

[0060] The substrate holding part 2 holds the substrate W1 approximately horizontally. Specifically, the substrate holding part 2 holds the substrate W1 in a posture such that the thickness direction of the substrate W1 is along the vertical direction. Here, the upper surface (first main surface) of the substrate W1 is the etching target surface. In addition, the substrate holding part 2 rotates the substrate W1 around a vertical rotation axis A1 passing through the central part of the substrate W1. Figure 1 In the example, the substrate holding portion 2 includes a spin chuck 21 and a rotation mechanism 22 .

[0061] The rotating chuck 21 is a component for holding the substrate W1, and includes a rotating base 211, a plurality of chuck pins 212, and a chuck opening and closing mechanism 213. The rotating base 211 has a substantially circular plate shape, and its upper surface is spaced apart from the lower surface of the substrate W1 and faces each other. A plurality of chuck pins 212 are protrudingly disposed on the upper surface of the rotating base 211. A plurality of chuck pins 212 are disposed at positions approximately equally spaced along the periphery of the substrate W1, and hold the periphery of the substrate W1. The chuck opening and closing mechanism 213 can open and close the chuck pins 212. Specifically, the chuck opening and closing mechanism 213 can switch between a closed state in which the chuck pins 212 hold the periphery of the substrate W1 and an open state in which the chuck pins 212 are separated from the periphery of the substrate W1. The chuck opening and closing mechanism 213 is controlled by the control unit 5.

[0062] The rotating mechanism 22 is a mechanism for rotating the rotating chuck 21 around the rotating axis A1, and includes a rotating shaft 221 and a rotating motor 222. The rotating shaft 221 extends vertically downward from the central portion of the rotating base 211. The rotating motor 222 transmits a rotating force to the rotating chuck 21 by rotating the rotating shaft 221 around the rotating axis A1, so that the rotating chuck 21 rotates around the rotating axis A1. As a result, the substrate W1 held on the rotating chuck 21 also rotates around the rotating axis A1. The rotating motor 222 is controlled by the control unit 5.

[0063] For example, at least a portion of the spin chuck 21 is formed of an insulator (eg, ceramic), and the substrate W1 is insulated via the spin chuck 21 .

[0064] The mixed liquid supply unit 3 supplies a first mixed liquid to the substrate W1 held by the substrate holding unit 2 to charge the substrate W1. The first mixed liquid is a mixed liquid obtained by mixing pure water (DIW: Deionized Water) and carbon dioxide at a first mixed concentration. Figure 1 In the example of , the mixed liquid supply unit 3 supplies the first mixed liquid to the lower surface (second main surface) of the substrate W1. Specifically, the mixed liquid supply unit 3 includes a nozzle 31, a mixed liquid supply pipe 32, a mixing unit 33, a pure water supply pipe 34, a pure water supply source 35, a carbon dioxide supply pipe 36, a carbon dioxide supply source 37, a supply valve 38, and a supply valve 39.

[0065] The nozzle 31 is provided below the substrate W1 . More specifically, the nozzle 31 is provided at a position where its discharge port faces the center of the lower surface of the substrate W1 with a gap therebetween. The nozzle 31 is connected to a mixing unit 33 via a mixed liquid supply pipe 32 . Figure 1 In the example of FIG. 2 , the rotating shaft 221 is a hollow shaft, and the mixed liquid supply pipe 32 passes through the rotating shaft 221. The mixing section 33 is connected to the pure water supply source 35 via the pure water supply pipe 34, and is connected to the carbon dioxide supply source 37 via the carbon dioxide supply pipe 36. The pure water supply source 35 supplies pure water to the mixing section 33 via the pure water supply pipe 34, and the carbon dioxide supply source 37 supplies carbon dioxide to the mixing section 33 via the carbon dioxide supply pipe 36. The mixing section mixes pure water and carbon dioxide at a first mixed concentration to generate a first mixed liquid, and supplies the first mixed liquid to the nozzle 31 via the mixed liquid supply pipe 32. The nozzle 31 ejects the first mixed liquid from its ejection port to the central portion of the lower surface of the substrate W1.

[0066] A supply valve 38 is provided in the middle of the pure water supply pipe 34. The supply valve 38 switches the opening and closing of the flow path in the pure water supply pipe 34. The supply valve 38 may be a valve capable of adjusting the flow rate of pure water flowing through the flow path in the pure water supply pipe 34. The supply valve 38 is controlled by the control unit 5.

[0067] A supply valve 39 is provided in the middle of the carbon dioxide supply pipe 36. The supply valve 39 switches the opening and closing of the flow path in the carbon dioxide supply pipe 36. The supply valve 39 may be a valve capable of adjusting the flow rate of carbon dioxide flowing through the flow path in the carbon dioxide supply pipe 36. The supply valve 39 is controlled by the control unit 5.

[0068] By appropriately adjusting the flow rates of pure water and carbon dioxide using the supply valves 38 and 39 , respectively, the mixing unit 33 can mix pure water and carbon dioxide at a predetermined first mixed concentration.

[0069] If the first mixed liquid is supplied to the lower surface of the substrate W1 during the rotation of the substrate W1, the first mixed liquid landed on the central portion of the lower surface of the substrate W1 spreads over the entire lower surface of the substrate W1 due to the centrifugal force, and scatters from the periphery of the substrate W1 to the outside. At this time, the lower surface of the substrate W1 is charged due to the friction between the first mixed liquid and the substrate W1.

[0070] Figure 3 This is a diagram showing an example of charge distribution on the upper surface of the substrate W1. Figure 3 The charge amounts (experimental values) at a plurality of measurement positions on the surface of the substrate W1 are shown. One of the measurement positions is the center of the substrate W1, and the other measurement positions are positions arranged at substantially equal intervals along the diameter of the substrate W1.

[0071] Figure 41 is a diagram schematically showing an example of the structure of the substrate W1 used in the experiment. The substrate W1 includes a silicon layer 1a, a silicon oxide film 1b formed on the upper surface of the silicon layer 1a, and a silicon oxide film 1c formed on the lower surface of the silicon layer 1a.

[0072] Figure 3 The solid curve represents Figure 4 The charge distribution when pure water is supplied to the lower surface of the substrate W1 shown in FIG. Figure 3 The dashed curve represents Figure 4 The potential distribution when the second mixed liquid to be described below is supplied to the lower surface of the substrate W1 shown in FIG. 2 is a mixed liquid obtained by mixing pure water and carbon dioxide at a second mixed concentration having a carbon dioxide concentration higher than the first mixed concentration. Figure 3 For reference, the double-dashed line curve shows the potential distribution when the processing liquid is not supplied to the lower surface of the substrate W1. When the processing liquid is not supplied, the charge amount of the upper surface of the substrate W1 is substantially zero.

[0073] like Figure 3 As shown in the solid line graph, when pure water is supplied to the lower surface of substrate W1, the lower surface of substrate W1 is positively charged due to the friction between the lower surface of substrate W1 and pure water. If the lower surface of substrate W1 is positively charged, positive charges are collected on the upper surface side of substrate W1 due to the induced polarization inside substrate W1. As a result, the polarity of the charge on the upper surface of substrate W1 becomes positive (see also Figure 4 ). In other words, the upper surface of the substrate W1 is positively charged.

[0074] The resistivity of pure water is relatively large, for example, more than 10 [MΩ·cm], so the charge on the lower surface of the substrate W1 is relatively large, and as a result, the charge on the upper surface of the substrate W1 also increases. However, if the charge on the upper surface of the substrate W1 becomes too large, if a pattern is formed on the upper surface of the substrate W1, it may have an adverse effect on the pattern. Figure 3 It can be seen that the non-uniformity of the charge distribution on the upper surface side of the substrate W1 becomes larger when pure water is used.

[0075] In contrast, when the second mixed liquid is supplied, the upper surface of the substrate W1 is only slightly charged (see Figure 3 ). Specifically, the center of the upper surface of the substrate W1 is slightly negatively charged, and the peripheral portion closer to the periphery than the center is slightly positively charged. The reason why the substrate W1 is almost not charged is as follows. That is, the concentration of carbon dioxide in the second mixed liquid is much higher than that of pure water, so the resistivity of the second mixed liquid is much smaller than that of pure water, so the lower surface of the substrate W1 is not easily charged. Therefore, the charge on the upper surface side of the substrate W1 is relatively small. On the other hand, according to Figure 3It can be seen that when the second mixed liquid having a smaller specific resistance value is used, the unevenness of the charge distribution on the substrate W1 becomes smaller.

[0076] As described above, if pure water is used, the charge amount may be too high and the unevenness of charge distribution may be large. On the other hand, if the second mixed liquid is used, the substrate W1 may hardly be charged, but the unevenness of charge distribution is small.

[0077] Therefore, the mixed liquid supply unit 3 supplies the first mixed liquid to the lower surface of the substrate W1. The first mixed concentration of the first mixed liquid is set to have a lower concentration of carbon dioxide than the second mixed concentration of the second mixed liquid. That is, the resistivity of the first mixed liquid is smaller than that of pure water and greater than the second mixed concentration. Thus, the entire upper surface of the substrate W1 can be charged with a charge within an appropriate range and with less unevenness.

[0078] The first mixed concentration of the first mixed solution may be based on Figure 3 It is preferably determined in advance based on the charge distribution on the substrate W1 shown in FIG. It is preferable to conduct experiments to change the first mixed concentration and obtain more charge distributions with respect to the first mixed concentration. In this way, a more optimal first mixed concentration can be determined.

[0079] Reference Figure 1 The etching liquid supply unit 4 supplies etching liquid to the upper surface of the substrate W1 held by the substrate holding unit 2. As the etching liquid, an etching liquid corresponding to the etching object on the upper surface of the substrate W1 is used. As the etching liquid, an acidic etching liquid can be used, and an alkaline etching liquid can also be used. As a specific example, hydrofluoric acid (HF), buffered hydrofluoric acid (BHF), ammonium fluoride (NH4F), ammonium hydroxide (NH4OH), tetramethylammonium hydroxide (TMAH), phosphoric acid (H3PO4), hydrogen peroxide (H2O2), or a mixture of at least two of them can be used.

[0080] The etching liquid supply unit 4 includes a nozzle 41, an etching liquid supply pipe 42, a supply valve 43, and an etching liquid supply source 44. The nozzle 41 is arranged above the substrate W1. Specifically, the nozzle 41 is arranged at a position where its nozzle is spaced apart from the central part of the upper surface of the substrate W1 and faces each other. The nozzle 41 is connected to the etching liquid supply source 44 via the etching liquid supply pipe 42. The etching liquid from the etching liquid supply source 44 is supplied to the nozzle 41 via the etching liquid supply pipe 42. The nozzle 41 sprays the etching liquid from its nozzle to the upper surface of the substrate W1.

[0081] The supply valve 43 is provided in the middle of the etching liquid supply pipe 42 to switch the opening and closing of the flow path in the etching liquid supply pipe 42. The supply valve 43 may also be a valve capable of adjusting the flow rate of the etching liquid flowing through the flow path in the etching liquid supply pipe 42. The supply valve 43 is controlled by the control unit 5.

[0082] By spraying the etching liquid onto the upper surface of the substrate W1 during the rotation of the substrate W1, the etching liquid landing on the center portion is subjected to centrifugal force and spreads over the entire upper surface of the substrate W1, and then scatters from the periphery of the substrate W1. The etching liquid acts on the entire upper surface of the substrate W1 to etch the etching object on the upper surface of the substrate W1.

[0083] Figure 1 In the example, a shielding plate 7 is provided. The shielding plate 7 is provided above the substrate holding portion 2, and is spaced apart from and opposed to the upper surface of the substrate W1. The lower surface of the shielding plate 7 is formed into a substantially circular shape having a diameter longer than the diameter of the substrate W1, and is opposed to the upper surface of the substrate W1 as a whole. The shielding plate 7 is connected to a lifting mechanism 71. The lifting mechanism 71 has, for example, a ball screw mechanism, which enables the shielding plate 7 to be raised and lowered between a processing position close to the substrate W1 and a standby position away from the substrate W1. In the substrate processing apparatus 100, a rotating mechanism that rotates the shielding plate 7 around the rotation axis A1 may also be provided. The lifting mechanism 71 and the rotating mechanism are controlled by the control unit 5.

[0084] Figure 1 In the example, a through hole is formed in the center of the shielding plate 7, which passes through the shielding plate 7 in the vertical direction, and the nozzle 41 is provided on the substrate W1 side in the through hole. By raising and lowering the shielding plate 7, the nozzle 41 is also raised and lowered together with the shielding plate 7.

[0085] Figure 1 In the example of FIG. 1 , a rinse liquid supply unit 6 is provided in the substrate processing apparatus 100 . The rinse liquid supply unit 6 supplies the rinse liquid to the surface of the substrate W1 held by the substrate holding unit 2 to rinse the etching liquid on the upper surface of the substrate W1 .

[0086] Here, the rinsing liquid supply unit 6 supplies the first rinsing liquid and the second rinsing liquid. The first rinsing liquid is, for example, pure water, or a third mixed liquid of pure water and carbon dioxide. In the case where the first rinsing liquid is the third mixed liquid, the concentration of carbon dioxide in the first rinsing liquid is greater than the concentration of carbon dioxide in the first mixed liquid supplied by the mixed liquid supply unit 3. That is, the mixed liquid supply unit 3 supplies the first mixed liquid to charge the substrate W1, and the rinsing liquid supply unit 6 supplies the first rinsing liquid to rinse the etching liquid of the substrate W1, so the concentration of carbon dioxide in the first rinsing liquid is set to be greater than that of the first mixed liquid. In this way, the charging of the substrate W1 can be suppressed on the one hand, and the etching liquid can be rinsed on the other hand.

[0087] The second rinse liquid is a rinse liquid having higher volatility than the first rinse liquid, and is, for example, isopropyl alcohol (IPA). By supplying the second rinse liquid after supplying the first rinse liquid, the substrate W1 can be easily dried.

[0088] Figure 1In the example of FIG. 1 , the rinse liquid supply unit 6 includes a nozzle 61, a common pipe 62, a first rinse liquid supply pipe 63, a second rinse liquid supply pipe 64, a supply valve 65, a supply valve 66, a first rinse liquid supply source 67, and a second rinse liquid supply source 68. The nozzle 61 is disposed above the substrate W1. Specifically, the nozzle 61 is disposed at a position where its ejection port is spaced apart from the central portion of the upper surface of the substrate W1 and faces each other. Figure 1 In the example of FIG. 7 , the nozzle 61 is also provided on the substrate W1 side in the through hole of the shielding plate 7. As the shielding plate 7 is raised and lowered, the nozzle 61 is also raised and lowered integrally.

[0089] The nozzle 61 is connected to one end of the common pipe 62. The other end of the common pipe 62 is connected to the first rinsing liquid supply source 67 via the first rinsing liquid supply pipe 63, and is connected to the second rinsing liquid supply source 68 via the second rinsing liquid supply pipe 64. The first rinsing liquid from the first rinsing liquid supply source 67 is supplied to the nozzle 61 via the first rinsing liquid supply pipe 63 and the common pipe 62. The nozzle 61 sprays the first rinsing liquid onto the upper surface of the substrate W1 from its spray outlet. The second rinsing liquid from the second rinsing liquid supply source 68 is supplied to the nozzle 61 via the second rinsing liquid supply pipe 64 and the common pipe 62. The nozzle 61 sprays the second rinsing liquid onto the upper surface of the substrate W1 from its spray outlet.

[0090] The supply valve 65 is provided in the middle of the first rinse liquid supply pipe 63 to switch the opening and closing of the flow path in the first rinse liquid supply pipe 63. The supply valve 65 may also be a valve capable of adjusting the flow rate of the first rinse liquid flowing through the flow path in the first rinse liquid supply pipe 63. The supply valve 65 is controlled by the control unit 5.

[0091] The supply valve 66 is provided in the middle of the second rinse liquid supply pipe 64 to switch the opening and closing of the flow path in the second rinse liquid supply pipe 64. The supply valve 66 may also be a valve capable of adjusting the flow rate of the second rinse liquid flowing through the flow path in the second rinse liquid supply pipe 64. The supply valve 66 is controlled by the control unit 5.

[0092] Furthermore, Figure 1 In the example of FIG. 5 , the nozzle 61 is used in common by the first rinse liquid and the second rinse liquid, but the present invention is not necessarily limited to this. The nozzle for the first rinse liquid and the nozzle for the second rinse liquid may also be provided separately.

[0093] Figure 1In the example, a gas supply unit 8 is provided in the substrate processing device 100. The gas supply unit 8 supplies an inactive gas to the space between the substrate holding unit 2 and the shielding plate 7. As the inactive gas, nitrogen or argon can be used, for example. The gas supply unit 8 includes a nozzle 81, a gas supply pipe 82, a supply valve 83, and a gas supply source 84. The nozzle 81 is disposed above the substrate W1. Specifically, the nozzle 81 is disposed at a position where its nozzle is spaced apart from the central part of the upper surface of the substrate W1 and is opposite to each other. The nozzle 81 is a through hole provided in the shielding plate 7. The nozzle 81 is connected to the gas supply source 84 via the gas supply pipe 82. The inactive gas from the gas supply source 84 is supplied to the nozzle 81 via the gas supply pipe 82. The nozzle 81 ejects the inactive gas from its nozzle.

[0094] The supply valve 83 is provided in the middle of the gas supply pipe 82 to switch the opening and closing of the flow path in the gas supply pipe 82. The supply valve 83 may be a valve capable of adjusting the flow rate of the gas flowing through the flow path in the gas supply pipe 82. The supply valve 83 is controlled by the control unit 5.

[0095] The control unit 5 controls the entire substrate processing device 100 in an integrated manner. The hardware structure of the control unit 5 is the same as that of a general computer. That is, the control unit 5 has a central processing unit (CPU) for performing various calculations, a read-only memory (ROM) for storing basic programs, a random access memory (RAM) for storing various information, and a disk for storing control software or data. The operation of the substrate processing device 100 is performed by executing a prescribed processing program by the CPU of the control unit 5. Furthermore, part or all of the functions of the control unit 5 can also be realized by a dedicated hardware circuit.

[0096] <Operation of Substrate Processing Apparatus 100 >

[0097] Figure 5 It is a flowchart showing an example of the operation of the substrate processing apparatus 100. The shielding plate 7 is initially located at the standby position. First, the substrate holding part 2 is made to hold the substrate W1 (process S1: substrate holding process). Specifically, the substrate transfer robot not shown in the figure delivers the substrate W1 to the substrate holding part 2, and the substrate holding part 2 holds the substrate W1. Next, the control part 5 controls the lifting mechanism 71 to move the shielding plate 7 to the processing position (process S2). Next, the control part 5 controls the rotating mechanism 22 to start the rotation of the substrate W1 (process S3). Specifically, the control part 5 starts the rotation motor 222 to rotate. As a result, the substrate W1 held on the rotary chuck 21 starts to rotate.

[0098] Next, the control unit 5 controls the mixed liquid supply unit 3 to supply the first mixed liquid to the lower surface of the substrate W1 (process S4: charging process). Specifically, the control unit 5 opens the supply valve 38 and the supply valve 39. As a result, the first mixed liquid is sprayed from the nozzle 31 of the mixed liquid supply unit 3 toward the central part of the lower surface of the substrate W1. The first mixed concentration (pure water: carbon dioxide) of the first mixed liquid is set in such a way that the entire upper surface of the substrate W1 is positively charged. For example, the first mixed concentration is set to less than 1 [ppm]. The rotation speed of the substrate W1 in the charging process is set, for example, to about.

[0099] The first mixed liquid landed on the central portion of the lower surface of the substrate W1 spreads over the entire lower surface of the substrate W1 and scatters outward from the periphery of the substrate W1. At this time, the lower surface of the substrate W1 is charged due to the friction between the first mixed liquid and the substrate W1. Moreover, due to the charged lower surface of the substrate W1, induced polarization is generated inside the substrate W1, so that the upper surface of the substrate W1 is positively charged.

[0100] When, for example, a first predetermined time has passed since the supply of the first mixed liquid began, the control unit 5 causes the mixed liquid supply unit 3 to stop supplying the first mixed liquid. Specifically, the control unit 5 closes the supply valve 38 and the supply valve 39. The first predetermined time is the time required for the charge amount on the upper surface of the substrate W1 to reach a predetermined charge amount, and can be set in advance, for example.

[0101] Next, the control unit 5 controls the etching liquid supply unit 4 to supply the etching liquid to the upper surface of the substrate W1 (process S5: etching liquid supply process). Specifically, the control unit 5 opens the supply valve 43. As a result, the etching liquid is sprayed from the nozzle 41 of the etching liquid supply unit 4 toward the central part of the upper surface of the substrate W1. The etching liquid is subjected to centrifugal force on the upper surface of the substrate W1 and spreads over the entire surface, and flies outward from the periphery of the substrate W1. The etching liquid etches the etching object on the upper surface of the substrate W1. Since the upper surface of the substrate W1 is positively charged, the etching liquid easily enters the gaps between the patterns.

[0102] For comparison, the case where the upper surface of the substrate W1 is not positively charged is described. In this case, the upper surface of the substrate W1 is negatively charged by supplying an acidic or alkaline etching solution. As a result, the side walls of the pattern are also negatively charged. The charge of the side walls of the pattern repels the negative ions (e.g., hydrogen difluoride ions) in the etching solution, and it is difficult for the etching solution to enter the gap. As a result, poor etching occurs.

[0103] On the other hand, if the upper surface of the substrate W1 is positively charged as in the present embodiment, the etching liquid can easily enter between the patterns even if the gaps between the patterns are narrow, so that etching can be performed appropriately.

[0104] Moreover, in the above example, the mixed liquid supply unit 3 supplies the first mixed liquid to the lower surface of the substrate W1, so that the lower surface of the substrate W1 is charged. Therefore, as long as the charge on the lower surface of the substrate W1 is not removed, the polarity of the charge on the upper surface of the substrate W1 can be maintained positive by induced polarization. That is, in the etching liquid supply process, a part of the positive charge on the upper surface of the substrate W1 can be neutralized by the supply of the etching liquid, but as long as the charge on the lower surface of the substrate W1 is maintained, the polarity of the charge on the upper surface of the substrate W1 can be maintained positive. Therefore, during the entire etching supply process, the polarity of the charge on the upper surface of the substrate W1 can be maintained positive, so that etching can be properly performed during the entire period.

[0105] When, for example, the second predetermined time has passed since the start of the supply of the etching liquid, the control unit 5 stops the supply of the etching liquid by the etching liquid supply unit 4. Specifically, the control unit 5 closes the supply valve 43. The second predetermined time is the time required for sufficient etching and can be set in advance, for example.

[0106] Next, the control unit 5 controls the rinse liquid supply unit 6 to supply the first rinse liquid to the upper surface of the substrate W1 (process S6: cleaning process). Specifically, the control unit 5 opens the supply valve 65. As a result, the first rinse liquid is sprayed from the nozzle 61 toward the central part of the upper surface of the substrate W1. The first rinse liquid is pure water or the third mixed liquid. The first rinse liquid spreads on the upper surface of the substrate W1 to rinse the etching liquid. In other words, the etching liquid on the upper surface of the substrate W1 is replaced by the first rinse liquid.

[0107] When, for example, the third predetermined time has passed since the supply of the first rinse liquid started, the control unit 5 stops the supply of the first rinse liquid by the rinse liquid supply unit 6. Specifically, the control unit 5 closes the supply valve 65. The third predetermined time is the time required to sufficiently remove the etching liquid and can be set in advance, for example.

[0108] Next, the control unit 5 controls the rinse liquid supply unit 6 to supply the second rinse liquid to the upper surface of the substrate W1 (process S7). Specifically, the control unit 5 opens the supply valve 66. As a result, the second rinse liquid is ejected from the nozzle 61 toward the central portion of the upper surface of the substrate W1. The second rinse liquid spreads on the upper surface of the substrate W1 and rinses the first rinse liquid. In other words, the first rinse liquid on the upper surface of the substrate W1 is replaced by the second rinse liquid.

[0109] Next, the control unit 5 causes the mixed liquid supply unit 3 to supply the second mixed liquid to the lower surface of the substrate W1 (process S8: de-staticization process). The second mixed liquid is a mixed liquid obtained by mixing pure water and carbon dioxide at a second mixed concentration. The concentration of carbon dioxide in the second mixed concentration is greater than the first mixed concentration of the first mixed liquid. In other words, the second mixed liquid is a mixed liquid having a smaller specific resistance value than the first mixed liquid. The control unit 5 opens the supply valve 38 and the supply valve 39. The control unit 5 can control the supply valve 39 in a manner that the flow rate of carbon dioxide is higher than the flow rate of carbon dioxide in the charging process (process S4), or can control the supply valve 38 in a manner that the flow rate of pure water is lower than the flow rate of pure water in the charging process (process S4).

[0110] The second mixed liquid spreads on the lower surface of the substrate W1 and scatters outward from the periphery of the substrate W1. The second mixed liquid has a low specific resistance value, so the charge carried by the lower surface of the substrate W1 flows to the second mixed liquid, and the lower surface of the substrate W1 is de-charged. As a result, the upper surface of the substrate W1 is also de-charged.

[0111] When, for example, the fourth predetermined time has passed since the supply of the second mixed liquid started, the control unit 5 stops the supply of the second mixed liquid by the mixed liquid supply unit 3. Specifically, the control unit 5 closes the supply valve 38 and the supply valve 39. The fourth predetermined time is the time required to remove the charge on the lower surface of the substrate W1, and can be set in advance, for example.

[0112] Next, the control unit 5 performs a drying process to dry the substrate W1 (step S9: drying process). As a specific example, the control unit 5 supplies the inert gas to the gas supply unit 8 and increases the rotation speed of the substrate W1, thereby drying the substrate W1. Next, the control unit 5 controls the rotation mechanism 22 to end the rotation of the substrate W1 (step S10).

[0113] As described above, according to the substrate processing apparatus 100, the etching liquid is supplied to the upper surface of the substrate W1 while the upper surface of the substrate W1 is positively charged (steps S4 and S5). Therefore, even if the gaps between the patterns on the upper surface of the substrate W1 are narrow, the etching liquid can easily enter the gaps between the patterns, so that etching can be performed appropriately. Thus, the occurrence rate of poor etching can be reduced.

[0114] Furthermore, according to the substrate processing apparatus 100, it is not necessary to apply a voltage to the substrate W1 in order to charge the substrate W1. Therefore, it is not necessary to provide an application structure (such as an electrode, etc.) for applying a voltage to the substrate W1. Therefore, the substrate W1 can be charged with a simpler structure.

[0115] Furthermore, Figure 5 In the example, the control unit 5 performs the static elimination step (step S8), but when the static electricity of the substrate W1 is not a problem, the static elimination step may be omitted.

[0116] <Rotation speed>

[0117] The substrate holding unit 2 can also rotate the substrate W1 in such a manner that the rotation speed of the substrate W1 is higher in the charging step (step S4 ) than in the etching liquid supplying step (step S5 ). Figure 6 It is a diagram showing an example of the rotation speed of the substrate W1. Figure 6 In the example, in the charging process (process S4), the control unit 5 controls the rotating mechanism 22 to rotate the substrate W1 at a relatively high first rotation speed ω1. As a result, in the charging process, the friction between the first mixed liquid and the lower surface of the substrate W1 increases, thereby increasing the charge amount of the lower surface of the substrate W1. Alternatively, the time until the substrate W1 is charged to a specified voltage level can be shortened. As a result, the processing capacity of the substrate processing apparatus 100 can be increased.

[0118] At the beginning of the etching liquid supply process (process S5) immediately after the charging process, the control unit 5 controls the rotation mechanism 22 to rotate the substrate W1 at the second rotation speed ω2 which is lower than the first rotation speed ω1. After maintaining the second rotation speed ω2 at the beginning of the etching liquid supply process, the control unit 5 controls the rotation mechanism 22 to rotate the substrate W1 at the third rotation speed ω3 which is lower than the second rotation speed ω2.

[0119] As described above, at the beginning of the etching liquid supply process, the substrate W1 is rotated at a slightly higher second rotation speed. Thus, at the beginning of the etching liquid supply process, the etching liquid can be quickly spread on the upper surface of the substrate W1. If the etching liquid spreads to the entire surface of the substrate W1, the substrate W1 is rotated at a third rotation speed ω3 that is lower than the second rotation speed ω2. Thus, the fluidity of the etching liquid can be reduced, so that the etching liquid can act more appropriately on the upper surface of the substrate W1. Thus, the upper surface of the substrate W1 can be etched more appropriately.

[0120] <Sequence of the electrification process>

[0121] exist Figure 5 In the example, the control unit 5 performs the etching liquid supplying process (process S5) after the charging process (process S4) is completed. The charge distribution on the substrate W1 generated by supplying the first mixed liquid to the lower surface of the substrate W1 through this method tends to remain unchanged for a relatively long time of several minutes to tens of minutes and more than 1 hour depending on the situation, as long as the static electricity is not actively removed. Therefore, the movable conditions of the device required to obtain the desired charge distribution in the charging process and the movable conditions of the device in the etching liquid supplying process can be separated from each other. On the other hand, the etching liquid in the etching liquid supplying process is supplied toward the upper surface of the substrate W1, and the first mixed liquid in the charging process is supplied toward the lower surface of the substrate W2, so the control unit 5 can also perform processing in a partially or fully parallel manner of the two processes.

[0122] Figure 7 This is a diagram showing an example of the timing of the charging process and the etching liquid supply process. Figure 7 In the example, the control unit 5 starts the charging process at time t1. That is, the control unit 5 opens the supply valve 38 and the supply valve 39 of the mixed liquid supply unit 3 at time t1. Then, the control unit 5 starts the etching liquid supply process at time t2. That is, the control unit 5 opens the supply valve 43 of the etching liquid supply unit 4 at time t2. Then, the control unit 5 ends the charging process and the etching liquid supply process at time t3. That is, the control unit 5 closes the supply valve 38, the supply valve 39, and the supply valve 43 at time t3.

[0123] exist Figure 7 In the example, the control unit 5 starts the charging process before the etching liquid supply process. As a result, the upper surface of the substrate W1 is positively charged at the start of the etching liquid supply process. Therefore, in the early stage of the etching liquid supply process, the etching liquid also easily enters the gaps between the patterns.

[0124] and, Figure 7 In the example of FIG. 5 , the control unit 5 performs the charging process and the etching liquid supply process in parallel. Thus, the lower surface of the substrate W1 can be continuously charged during the etching liquid supply process. Furthermore, the charging of the upper surface of the substrate can be maintained more easily.

[0125] In addition, in the etching liquid supply process, the etching liquid is scattered from the periphery of the upper surface of the substrate W1 to the outside, and the first mixed liquid is scattered from the periphery of the lower surface of the substrate W1 to the outside. As a result, the etching liquid can be prevented from flowing back to the lower surface of the substrate W1 through the end surface of the substrate W1 (the end surface connecting the periphery of the upper surface and the periphery of the lower surface). Therefore, etching of the lower surface of the substrate W1 can be suppressed.

[0126] Figure 8 FIG. 2 is another diagram showing the timing of the charging process and the etching liquid supply process. Figure 8 In the example, the control unit 5 starts the etching liquid supplying process at time t11, starts the charging process at time t12, and ends the charging process and the etching liquid supplying process at time t13.

[0127] exist Figure 8 In the example, the control unit 5 starts the charging process after starting the etching liquid supply process. Therefore, in the initial period from the start of the etching liquid supply process to the start of the charging process, the substrate W1 is almost not charged. However, in the early stage of the etching liquid treatment process, the etching amount of the etching treatment is still small. That is, the etching has not progressed so much during this initial period, so the gap between the patterns is shallow. Therefore, Figure 8In the example, the charging process is not performed during the initial period of the etching liquid supply process, and the charging process is performed from the middle of the etching liquid supply process. After the moment t12 when the etching progresses to a certain extent, the substrate W1 is charged by the charging process, so that even if the gap between the patterns becomes deeper, the etching liquid can easily enter the deep gap between the patterns. Thus, etching can be performed appropriately.

[0128] Moreover, in Figure 8 In the example of Figure 7 Compared with the situation of the first mixed liquid, the consumption of the first mixed liquid can be reduced.

[0129] The substrate processing method and the substrate processing device are presented and described in detail above, but the above description is for illustration and not limitation in all aspects. Therefore, the substrate processing method and the substrate processing device can be appropriately modified and omitted within the scope of the disclosure. In addition, the above embodiments can be appropriately combined.

[0130] For example, as the first mixed liquid for charging and the second mixed liquid for de-charging, a mixed liquid obtained by mixing an additive gas other than carbon dioxide with pure water can also be used. As the additive gas, for example, hydrogen chloride gas or ammonia gas can be used. The concentration of the additive gas in the first mixed liquid is less than the concentration of the additive gas in the second mixed liquid. In terms of resistivity, the resistivity of the first mixed liquid is greater than the resistivity of the second mixed liquid. In this way, the lower surface of the substrate W1 can also be charged.

[0131] Alternatively, a mixture of pure water and a chemical solution may be used as the first mixed solution for charging and the second mixed solution for removing static electricity. As the chemical solution, for example, hydrochloric acid, ammonium water or TMHA (3-methyl-2-hexenoic acid) may be used. In this case, the resistivity of the first mixed solution is also greater than the resistivity of the second mixed solution. Thus, the lower surface of the substrate W1 may also be charged.

[0132] In addition, in the above example, the mixed liquid supply part 3 supplies the first mixed liquid to the lower surface of the substrate W1. However, the mixed liquid supply part 3 may also supply the first mixed liquid to the upper surface of the substrate W1. In this case, the nozzle 31 is arranged above the substrate W1. For example, the nozzle 31 is arranged at a position opposite to the central part of the upper surface of the substrate W1. The upper surface of the substrate W1 is positively charged by supplying the first mixed liquid to the upper surface of the substrate W1 by the mixed liquid supply part 3. Thereafter, the etching liquid supply part 4 supplies etching liquid to the upper surface of the positively charged substrate W1. Therefore, the etching liquid easily enters the gaps between the patterns.

[0133] However, the positive charge attached to the upper surface of the substrate W1 can be neutralized by supplying the etching liquid, thereby removing the charge. Therefore, during the etching liquid supply process, the charge on the upper surface of the substrate W1 decreases with the passage of time. Therefore, it is difficult to keep the upper surface of the substrate W1 positively charged throughout the etching liquid supply process.

[0134] Furthermore, when the mixed liquid supply unit 3 supplies the first mixed liquid to the upper surface of the substrate W1 , it becomes difficult to perform the charging process and the etching liquid supply process in parallel.

[0135] In addition, the unevenness of charge distribution on the upper surface of the substrate W1 to which the first mixed liquid is directly supplied becomes larger. The reason for this is that the closer the substrate W1 is to the periphery, the higher the rotation speed is, and the friction between the first mixed liquid and the surface of the substrate W1 increases on the peripheral side of the substrate W1. In other words, the reason for this is that the unevenness of the friction on the upper surface of the substrate W1 is large. As a result, the difference between the charge amount in the central part of the substrate W1 and the charge amount in the peripheral part becomes larger. Therefore, if the first mixed liquid is supplied to the upper surface of the substrate W1 so that the upper surface of the substrate W1 is charged, the unevenness of charge distribution on the upper surface of the substrate W1 becomes larger. As a result, the uniformity of etching can be reduced.

[0136] In contrast, if the first mixed liquid is supplied to the lower surface of the substrate W1, although the charge distribution on the lower surface of the substrate W1 is uneven, the charge distribution on the upper surface of the substrate W1 is less likely to be uneven than on the lower surface. This is because induced polarization is generated in the thickness direction of the substrate W1, and thus the uneven charge distribution becomes less uneven as it moves away from the lower surface of the substrate W1. Figure 3 As shown, in comparison, the charge distribution on the upper surface of the substrate W1 is more uniform.

[0137] [Description of Reference Numerals]

[0138] 2: Substrate holding part

[0139] 3: Mixed liquid supply unit

[0140] 4: Etching liquid supply unit

[0141] 5: Control Department

[0142] A1: Rotation axis

[0143] W1: substrate

[0144] S1: Substrate holding process (step)

[0145] S4: Charging process (step)

[0146] S5: Etching liquid supply process (step)

[0147] S6: Rinse liquid supply process (step)

[0148] S8: Anti-static process (step)

Claims

1. A substrate processing method, comprising: a substrate holding step of holding the substrate having the first main surface on which the pattern is formed by a substrate holding portion; a charging step of rotating the substrate around a rotation axis passing through a central portion of the substrate, supplying a first mixed solution obtained by mixing pure water and an additive gas at a first mixed concentration capable of positively charging the entire first main surface of the substrate to the substrate, so as to charge the substrate; and The etching liquid supplying step is performed after the charging step or in parallel with the charging step, wherein the substrate is rotated about the rotation axis and an acidic or alkaline etching liquid containing negative ions is supplied to the first main surface of the substrate.

2. The substrate processing method according to claim 1, wherein: The first mixed concentration is a value determined based on the charge distribution on the substrate.

3. The substrate processing method according to claim 1 or 2, wherein: In the charging step, the first mixed liquid is supplied to a second main surface of the substrate opposite to the first main surface. The substrate processing method further comprises a static elimination step. In the static elimination step, after the etching solution supply step, a second mixed solution having an additive gas concentration higher than the first mixed concentration is supplied to the second main surface of the substrate to eliminate static electricity from the substrate.

4. The substrate processing method according to claim 1 or 2, wherein: It also has a flushing liquid supply process. The rinse liquid supplying step is performed after the etching liquid supplying step, and supplies pure water or a third mixed liquid obtained by mixing pure water and an additive gas at a third mixed concentration different from the first mixed concentration to the first main surface of the substrate.

5. The substrate processing method according to claim 4, wherein: The concentration of the additional gas in the third mixed concentration is greater than the concentration of the additional gas in the first mixed concentration.

6. The substrate processing method according to claim 1 or 2, wherein: The above-mentioned added gas is carbon dioxide.

7. The substrate processing method according to claim 1 or 2, wherein: In the charging step, the substrate is rotated at a first rotation speed. In the etching liquid supplying step, the substrate is rotated at a second rotation speed that is lower than the first rotation speed.

8. The substrate processing method according to claim 7, wherein: In the etching liquid supplying step, after the substrate is rotated at the second rotation speed, the substrate is rotated at a third rotation speed that is lower than the second rotation speed.

9. The substrate processing method according to claim 1 or 2, wherein: The etching liquid supplying step is performed after the charging step is completed.

10. The substrate processing method according to claim 1 or 2, wherein: In the charging step, the first mixed liquid is supplied to a second main surface of the substrate opposite to the first main surface. The charging step and the etching liquid supplying step are performed in parallel.

11. The substrate processing method according to claim 10, wherein: The charging step is started before the etching solution supplying step is started.

12. The substrate processing method according to claim 10, wherein: The charging step is started after the etching solution supply step is started.

13. A substrate processing device comprising: A substrate holding portion that holds a substrate having a first main surface on which a pattern is formed, and rotates the substrate around a rotation axis passing through a central portion of the substrate; a mixed liquid supplying unit for supplying a first mixed liquid obtained by mixing pure water and an additive gas at a first mixed concentration capable of causing the entire first main surface of the substrate held on the substrate holding unit to be positively charged to the substrate, so as to charge the substrate; and The etching liquid supply unit supplies an acidic or alkaline etching liquid containing negative ions to the first main surface of the substrate held by the substrate holding unit.

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