Substrate processing method

Abstract

The present invention relates to a substrate processing method, and more particularly, to a substrate processing method in a substrate processing apparatus using a supercritical fluid, which can reduce damage or defect of a substrate when the supercritical fluid is supplied to the inside of a chamber. The substrate processing method includes: a pressurizing step of pressurizing to a preset process pressure by supplying the fluid through a lower portion of the chamber; an isobaric step of discharging the fluid while supplying the fluid toward the chamber so as to maintain the inside of the chamber at a constant pressure, and performing a processing process for the substrate; and a pressure reduction step of discharging the fluid from the inside of the chamber, and supplying the fluid to the chamber through a lower portion of the chamber in at least a partial section of the pressure reduction step.

Description

Technical Field

[0001] The present invention relates to a substrate processing method, and more particularly to a substrate processing method in a substrate processing apparatus using a supercritical fluid, in which damage or defects of the substrate can be reduced when the supercritical fluid is supplied to the interior of a chamber. Background Art

[0002] Generally, when manufacturing a large-scale / high-density semiconductor device such as LSI (Large scale integration) on the surface of a semiconductor wafer, it is necessary to form an extremely fine pattern on the wafer surface.

[0003] Such microscopic patterns are formed by various processes of exposing, developing, and cleaning a wafer coated with photoresist and patterning the photoresist, and then etching the wafer so that the photoresist pattern can be transferred to the wafer.

[0004] After such etching, the wafer is cleaned to remove dust or natural oxide film on the surface of the wafer. The cleaning process is performed by immersing the wafer with a pattern formed on the surface in a treatment liquid such as a chemical solution or a rinse liquid, or by supplying the treatment liquid to the surface of the wafer.

[0005] However, as semiconductor devices become more highly integrated, pattern collapse occurs when a process liquid is dried after a cleaning process, in which a pattern of a photoresist or a wafer surface collapses.

[0006] Such a pattern collapse is equivalent to, for example Fig.12 As shown, when the cleaning process is completed and the processing liquid 10 remaining on the surface of the substrate S is dried, if the processing liquid on the left and right of the patterns 11, 12, and 13 is dried unevenly, the capillary force that stretches the left and right patterns 11, 12, and 13 is unbalanced, resulting in the phenomenon that the patterns 11, 12, and 13 collapse in the direction where more processing liquid remains.

[0007] exist Fig.12 In the case of , the drying of the processing liquid in the left and right outer regions where no pattern is formed on the substrate S is completed, and the processing liquid 10 remains in the gaps between the patterns 11, 12, and 13. As a result, the patterns 11 and 13 on the left and right sides collapse inward due to the capillary force received from the processing liquid 10 remaining between the patterns 11, 12, and 13.

[0008] The capillary force causing the aforementioned pattern collapse is due to the surface tension of the processing liquid acting in the liquid / gas interface disposed between the atmosphere surrounding the substrate S after the cleaning process and the processing liquid remaining between the patterns.

[0009] Therefore, a treatment method for drying a treatment liquid using a fluid in a supercritical state (hereinafter referred to as a "supercritical fluid") that does not form an interface with a gas or a liquid has recently attracted attention.

[0010] exist Fig.13 In the state diagram of pressure and temperature, in the drying method of the prior art using only temperature regulation, the gas-liquid equilibrium line must be passed as shown by the hidden line, and therefore, capillary force is generated at the gas-liquid interface at this time.

[0011] In contrast, when drying is performed in a supercritical state by adjusting the temperature and pressure of the fluid, the substrate can be dried essentially without capillary force without passing through the gas-liquid equilibrium line.

[0012] Reference Fig.13 To observe the drying using supercritical fluid, if the pressure of the liquid is raised from A to B, and then the temperature is raised from B to C, it will not pass through the gas-liquid equilibrium line and will be converted to the supercritical state C. In addition, when the drying process is completed, the pressure of the supercritical fluid is reduced and it will not pass through the gas-liquid equilibrium line and will be converted into gas D.

[0013] On the other hand, when a supercritical fluid is used and supplied to the interior of the chamber, the substrate may be damaged (defect) due to the high pressure and flow rate of the supercritical fluid at the initial stage of supply. For this reason, in the existing device, the supercritical fluid is supplied from the bottom of the chamber in the pressurization step and from the top of the chamber in the isobaric step. However, in the case of supplying from the top of the chamber in the isobaric step, damage to the substrate cannot be reduced.

[0014] Specifically, in the pressurization step, in the isobaric step after supplying from the bottom of the chamber, in a state where the organic solvent cannot be fully replaced (mixed) due to the supercritical fluid, in the case of supplying from the top of the chamber, in the area where two phases (liquid-supercritical) coexist, the organic solvent is rapidly mixed by the flow of the supercritical fluid and flow separation of the organic solvent occurs. Therefore, more damage is likely to occur particularly in the central area of ​​the substrate to which the supercritical fluid is supplied. Summary of the invention

[0015] In order to solve the above-mentioned problems, the present invention aims to provide a substrate processing method which can reduce the damage of the substrate caused by the high pressure and flow rate of the supercritical fluid when the supercritical fluid is supplied to the chamber.

[0016] It may be that the object of the present invention as described above is achieved by a substrate processing method of a substrate processing device having a chamber that performs a processing process for a substrate using a fluid in a supercritical state, the substrate processing method comprising: a pressurizing step of pressurizing the fluid to a predetermined process pressure by supplying the fluid from below the chamber; an isobaric step of discharging the fluid while supplying the fluid to the chamber, thereby maintaining the interior of the chamber at a constant pressure and performing a processing process for the substrate; and a decompressing step of discharging the fluid from the interior of the chamber, and supplying the fluid to the chamber from below the chamber in at least a portion of the isobaric step.

[0017] Here, the isobaric step may include: a first supplying step of supplying the fluid to the chamber through a lower portion of the chamber; and a second supplying step of supplying the fluid to the chamber through an upper portion of the chamber.

[0018] Furthermore, the first supply step may be arranged in a predetermined interval in the pressure equalization step.

[0019] Furthermore, in the pressure-equalizing step, the first supplying step and the second supplying step may be repeated alternately.

[0020] On the other hand, in the pressure-equalizing step, the fluid may be supplied to the chamber only through a lower portion of the chamber.

[0021] In addition, in the pressure-equalizing step, a pulse wave caused by the fluid may be generated inside the chamber. In this case, in the pressure-equalizing step, an exhaust step of reducing the pressure of the fluid inside the chamber to a preset pressure may be performed, and then a first supply step of supplying the fluid to the chamber from the bottom of the chamber to re-pressurize the pressure inside the chamber to the process pressure may be performed.

[0022] According to the present invention having the above-mentioned structure, when a supercritical fluid is supplied to the chamber, the fluid can be supplied from below the chamber in at least a portion of the isobaric step following the pressurizing step, thereby reducing damage to the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a block diagram showing the structure of a substrate processing apparatus using a supercritical fluid according to an embodiment of the present invention,

[0024] Figure 2 It is shown in Figure 1 A side cross-sectional view of the structure of the chamber,

[0025] Figure 3is a graph showing changes in pressure inside a chamber according to a conventional substrate processing method.

[0026] Figures 4 to 6 is a diagram for explaining the operation of a substrate processing apparatus in each step of a processing process for a substrate.

[0027] Figures 7 to 10 is a graph showing the pressure change inside the chamber of the substrate processing method according to the present invention,

[0028] Fig.11 is a diagram showing the degree of damage to a substrate when a substrate is processed according to a conventional substrate processing method and a substrate processing method of the present invention,

[0029] Fig.12 is a diagram schematically showing a state in which a pattern collapses when a pattern on a substrate is dried according to the prior art.

[0030] Fig.13 This is a state diagram showing changes in pressure and temperature of a fluid in a process using a supercritical fluid.

[0031] (Explanation of Reference Numerals)

[0032] S: Substrate

[0033] 100: Fluid storage unit

[0034] 120: Main supply line

[0035] 122: Supply valve

[0036] 146: discharge line

[0037] 150: First Supply Line

[0038] 152: First valve

[0039] 160: Second Supply Line

[0040] 162: Second valve

[0041] 200: Temperature control unit

[0042] 300: Pressure regulation unit

[0043] 400: Chamber

[0044] 412: Processing Space

[0045] 450: Pallet

[0046] 540: Discharge valve

[0047] 600: Fluid Supply Department

[0048] 1000: Substrate processing equipment DETAILED DESCRIPTION

[0049] Hereinafter, the structure of a substrate processing apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0050] Figure 1 is a block diagram showing a structure of a substrate processing apparatus 1000 according to the prior art, Figure 2 is a side cross-sectional view showing the structure of the chamber 400 .

[0051] The substrate processing apparatus 1000 using supercritical fluid uses a fluid in a supercritical state to perform a processing process for a substrate S. Here, if the fluid in a supercritical state refers to a substance reaching a critical state, that is, reaching a state exceeding a critical temperature and a critical pressure, it is equivalent to a fluid having a formed phase. Such a fluid in a supercritical state has a molecular density close to that of a liquid and a viscosity close to that of a gas. Therefore, the diffusion force, penetration force, and solubility of the fluid in a supercritical state are very excellent, which is conducive to chemical reactions and has almost no surface tension and does not exert surface tension on fine structures. Therefore, in the drying process of semiconductor elements, not only is the drying efficiency excellent, but the pattern collapse phenomenon can also be avoided and it can be used very usefully.

[0052] In the present invention, carbon dioxide (CO2) can be used as a supercritical fluid. Carbon dioxide has a relatively low critical temperature of approximately 31.1°C and a relatively low critical pressure of 7.38 MPa, so it is easy to become a supercritical state, its state can be easily controlled by adjusting the temperature and pressure, and it is inexpensive.

[0053] In addition, carbon dioxide is non-toxic, harmless to the human body, and has non-flammable and inactive properties. Furthermore, the diffusion coefficient of carbon dioxide in a supercritical state is about 10 to 100 times higher than that of water or other organic solvents, and its permeability is very excellent, so that the organic solvent can be replaced quickly and there is almost no surface tension, which is beneficial for use in the drying process. In addition, the carbon dioxide used in the drying process can be converted into a gas state and the organic solvent can be separated for reuse, so the burden on environmental pollution is also small.

[0054] Reference Figure 1 as well as Figure 2 The substrate processing device 1000 may include: a chamber 400, which provides a processing space 412 for performing a processing process on a substrate S coated with a processing liquid or an organic solvent 10 (hereinafter referred to as "organic solvent") using a supercritical fluid; and a fluid supply unit 600, which supplies fluid to the chamber 400.

[0055] The fluid supply part 600 may adjust at least one of the temperature and the pressure of the fluid to supply the fluid to the chamber 400 through the main supply line 120 .

[0056] For example, the fluid supply unit 600 may include: a fluid storage unit 100 storing the fluid; and a main supply line 120 connecting the fluid storage unit 100 and the chamber 400 .

[0057] In this case, a pressure regulating unit 200 and a temperature regulating unit 300 may be arranged along the main supply line 120. At this time, the pressure regulating unit 200 may be composed of, for example, a pressure pump, and the temperature regulating unit 300 may be composed of a heater or a heat exchanger for heating the fluid.

[0058] Furthermore, the main supply line 120 may further include a sensing unit (not shown) for sensing at least one of the pressure and the temperature of the fluid. The pressure and the temperature of the fluid flowing in the main supply line 120 may be adjusted according to the pressure and the temperature sensed in the sensing unit. To this end, the substrate processing apparatus 1000 according to an embodiment of the present invention may include a control unit (not shown) for controlling the pressure regulating unit 200 and the temperature regulating unit 300. The control unit may control the pressure regulating unit 200 and the temperature regulating unit 300 based on the pressure and the temperature sensed in the sensing unit.

[0059] On the other hand, when performing a processing process on the substrate S, the temperature and pressure of the processing space 412 of the chamber 400 must be maintained above the critical temperature and the critical pressure so that the fluid supplied to the inside of the chamber 400 can be converted into a supercritical state.

[0060] To this end, when the fluid moves along the main supply line 120 , the fluid may be pressurized to a critical pressure or a pressure above the critical pressure by the pressure regulating part 200 , and further, the fluid may be heated to a critical temperature or a temperature above the critical temperature by the temperature regulating part 300 .

[0061] On the other hand, the main supply line 120 may be configured to include: a first supply line 150 connected to the upper portion of the chamber 400; and a second supply line 160 connected to the lower portion of the chamber 400. The first supply line 150 may be connected to the substantially central portion of the upper portion of the chamber 400, and similarly, the second supply line 160 may be connected to the substantially central portion of the lower portion of the chamber 400. Before the main supply line 120 branches into the first supply line 150 and the second supply line 160, a supply valve 122 may be provided on the main supply line 120.

[0062] In addition, the first supply line 150 may be provided with a first valve 152 for controlling the flow of the fluid by opening / closing, and the second supply line 160 may also be provided with a second valve 162 for controlling the flow of the fluid by opening / closing.

[0063] Furthermore, although not shown in the drawings, a first filter for filtering foreign matter and the like in the fluid may be provided in the first supply line 150, and a second filter for filtering foreign matter and the like in the fluid may also be provided in the second supply line 160. In this case, the first filter may be arranged at the front end of the first valve 152 in the flow direction of the fluid in the first supply line 150. In addition, the second filter may also be arranged at the front end of the second valve 162 in the flow direction of the fluid in the second supply line 160.

[0064] In addition, the chamber 400 may be further provided with a discharge line 146 for discharging the fluid in the processing space 412 to the outside. During or after the processing of the substrate S, the fluid may be discharged from the inside of the chamber 400 to the outside through the discharge line 146. The discharge line 146 may be provided with a discharge valve 540, which may be composed of a proportional control valve, for example.

[0065] In addition, the discharge line 146 may be spaced apart from the central portion of the lower portion of the chamber 400. As shown above, the second supply line 160 is connected to the central portion of the lower portion of the chamber 400, so the discharge line 146 may be spaced apart from the central portion of the lower portion of the chamber 400 to avoid interference with the second supply line 160.

[0066] On the other hand, the chamber 400 may provide a processing space 412 for performing a processing process such as a drying process on the substrate S using a fluid in a supercritical state. The chamber 400 may have an opening (not shown) formed on one side and may be made of a material suitable for processing a high-pressure process on the substrate S on the inside.

[0067] The processing space 412 of the chamber 400 may be kept in a sealed state, and the pressure of the fluid supplied to the processing space 412 may be kept above a critical pressure.

[0068] In addition, the chamber 400 may further include a heating unit (not shown) to maintain the temperature of the processing space 412 at a predetermined temperature or higher. The heating unit may maintain the temperature of the processing space 412 or the temperature of the fluid contained in the processing space 412 at a critical temperature or higher during the process of the substrate S.

[0069] On the other hand, a tray 450 for supporting the substrate S may be provided in the chamber 400 .

[0070] The tray 450 may be introduced into the processing space 412 of the chamber 400 through the opening of the chamber 400 or may be introduced from the processing space 412 to the outside of the chamber 400 through the opening.

[0071] Figure 3 is a graph showing a pressure change inside the chamber 400 according to a process for the substrate S in the substrate processing apparatus 1000 according to a conventional substrate processing method. Figures 4 to 6 1 is a diagram for explaining the operation of the substrate processing apparatus 1000 in each step of the processing process for the substrate. Hereinafter, the processing process for the substrate S of the substrate processing apparatus 1000 will be observed with reference to the accompanying drawings.

[0072] Reference Figure 3 In the case of the preparation step (D1: 0-T1) in which the tray 450 is inserted into and docked with the chamber 400 before the process for the substrate S is started, the pressure inside the chamber 400 may be equivalent to the atmospheric pressure.

[0073] Next, a pressurizing step (D2: T1 to T3) is performed to increase the pressure inside the chamber 400.

[0074] In the pressurizing step, a high-pressure fluid is supplied to the chamber 400, and the fluid is not discharged from the chamber 400. Therefore, the pressure inside the chamber 400 increases and exceeds the critical pressure Pc to a preset pressure.

[0075] For example, it could be, Figure 4 As shown, the supply valve 122 of the main supply line 120 is opened, the first valve 152 of the first supply line 150 and the discharge valve 540 of the discharge line 146 are closed, and the second valve 162 of the second supply line 160 is opened so that fluid can be supplied from below the chamber 400 .

[0076] When the pressure of the chamber 400 reaches a preset process pressure P1 , fluid may be supplied to the interior of the chamber 400 through the second supply line 160 .

[0077] If the fluid is supplied from the pressurizing step through the upper part of the chamber 400, the fluid may be directly supplied from the upper part of the chamber 400 toward the substrate S. In this case, the high-speed fluid may make the organic solvent on the substrate S unstable, and further, the pattern (not shown) formed on the upper part of the substrate S may be damaged (defect) due to the high-speed fluid.

[0078] Therefore, in the pressurizing step, the fluid is supplied from below the chamber 400 through the second supply line 160. When the fluid is supplied from below the chamber 400, the fluid is blocked by the tray 450 and is not directly supplied toward the substrate S, thereby preventing damage to the pattern on the substrate S.

[0079] Reference Figure 3 , followed by the pressurization step D2, and then the isobaric step (or pressure maintaining step) D3.

[0080] In the isobaric step D3, Figure 5 As shown, the supply valve 122 of the main supply line 120 can be maintained in an open state, and the fluid can be supplied through the upper part of the chamber 400 by opening the first valve 152 of the first supply line 150 and the discharge valve 540 of the discharge line 146, and closing the second valve 162 of the second supply line 160.

[0081] In this case, while the fluid is continuously supplied to the chamber 400 through the first supply line 150 , the fluid of an amount equivalent to the supplied fluid is discharged to the outside of the chamber 400 through the discharge line to keep the pressure inside the chamber 400 constant.

[0082] Then the aforementioned isobaric step D3, as Figure 3 As shown, a decompression step D4 is performed. In the decompression step D4, as Figure 6 As shown, the first valve 152 of the first supply line 150 and the second valve 162 of the second supply line 160 may be completely closed, and the discharge valve 540 of the discharge line 146 may be opened to discharge the fluid inside the chamber 400 .

[0083] That is, the fluid is not supplied into the chamber 400 , and the fluid is discharged to the outside of the chamber 400 through the discharge line 146 to reduce the pressure inside the chamber 400 .

[0084] On the other hand, as mentioned above, in the pressurization step D2, in order to reduce damage to the substrate S, the fluid is supplied from the bottom of the chamber 400, and in the isobaric step D3 in which the process pressure P1 is reached inside the chamber 400, the fluid is supplied from the top of the chamber 400.

[0085] However, according to the test conducted by the present inventors, it was confirmed that in the pressure-equalizing step D3 , when the fluid was supplied from above the chamber 400 , the substrate S was often damaged even after the process pressure P1 was reached inside the chamber 400 .

[0086] It is explained that even when the process pressure P1 is reached inside the chamber 400 , the substrate S may be damaged due to the high-pressure and high-speed fluid supplied from the upper side of the chamber 400 .

[0087] Therefore, the present invention is intended to provide a substrate processing method that can reduce damage to the substrate (S) caused by the fluid when the fluid is supplied to the inside of the chamber 400 .

[0088] The substrate processing method according to the present invention includes: a pressurizing step D2, in which the fluid is supplied from the bottom of the chamber 400 to be pressurized to a predetermined process pressure P1; an isobaric step D3, in which the fluid is discharged while supplying the fluid toward the chamber 400 to maintain a constant pressure inside the chamber 400, and a processing process is performed on the substrate S; and a decompressing step D4, in which the fluid is discharged from the inside of the chamber 400. In at least a part of the isobaric step D3, the fluid can be supplied to the chamber 400 from the bottom of the chamber 400.

[0089] Figures 7 to 10 1 is a graph showing the pressure change inside the chamber 400 according to the substrate processing method of the present invention. In the figure, the dotted line indicates the situation where the fluid is supplied from the bottom of the chamber 400 (Bottom flow), the dotted line indicates the situation where the fluid is supplied from the top of the chamber 400 (Top flow), and the double-dotted line indicates the situation where the fluid is discharged from the chamber 400 (Vent).

[0090] like Figure 7 As shown, the isobaric step D3 may include: a first supplying step D31, supplying the fluid to the chamber 400 through the bottom of the chamber 400; and a second supplying step D32, supplying the fluid to the chamber 400 through the top of the chamber 400. In the first supplying step D31 and the second supplying step D32, the chamber 400 and the substrate processing apparatus 1000 are driven at Figure 4 and Figure 5 It has been described in detail in , so repeated description is omitted.

[0091] For example, the first supply step D31 may be performed after the aforementioned pressurizing step D2, and the second supply step D32 may be performed after reaching a predetermined conversion time Tt. The aforementioned decompression step D4 may be performed after the second supply step D32. In this embodiment, the aforementioned first supply step D31 and the second supply step D32 may be performed once each.

[0092] That is, in the present invention, in the isobaric step D3, the time for supplying the fluid from the bottom of the chamber 400 is slower than that of the existing method, thereby minimizing damage to the substrate S, rather than directly supplying the fluid to the chamber 400 from above the chamber 400 .

[0093] On the other hand, the transition time Tt may be determined as a predetermined time from the start time T3 of the equal pressure step D3 or may be determined in consideration of various process conditions for the substrate S.

[0094] In addition, although not shown in the drawings, in the pressure-equalizing step D3, the first supplying step D31 may be configured to be performed in a predetermined interval.

[0095] That is, in Figure 7 The description is that the first supply step D31 is configured in the initial area of ​​the isobaric step D3, but it is not limited to this. The first supply step D31 can of course also be configured in the middle area or the late area of ​​the isobaric step D3.

[0096] Further, if Figure 8 As shown, in the isobaric step D3, the first supply step D31 and the second supply step D32 can be performed alternately and repeatedly.

[0097] For example, the first supply step D31 and the second supply step D32 may be alternately repeated twice. That is, the first supply step D31 may be performed after the pressurizing step D2, and the second supply step D32 may be performed when the first conversion time Tt1 is reached, and the first supply step D31 may be performed when the second conversion time Tt2 is reached, and the second supply step D32 may be performed when the third conversion time Tt3 is reached.

[0098] The number of repetitions of the first supply step D31 and the second supply step D32 is described by way of example only and can be modified as appropriate.

[0099] In addition, in Figure 8 When the first supply step D31 and the second supply step D32 are repeated alternately, the flow of the fluid inside the chamber 400 continuously changes, and the dead zone on the substrate S where the organic solvent 10 is not replaced can be reduced.

[0100] On the other hand, Fig. 9 As shown, in the pressure-equalizing step D3 , the fluid may be supplied to the chamber 400 only through the bottom of the chamber 400 .

[0101] In this case, the fluid is supplied only through the lower portion of the chamber 400 , thereby having an advantage that damage to the substrate S can be minimized.

[0102] Further, if Fig.10 As shown, in the pressure-equalizing step D3, the chamber 400 may be driven in a manner such that a pulse wave caused by the fluid is generated inside the chamber 400.

[0103] For example, refer to Fig.10 In the isobaric step D3, first, an exhaust step D41 can be performed to reduce the fluid inside the chamber 400 to a constant pressure P2, and then a first supply step D51 can be performed to supply the fluid to the chamber 400 through the lower direction of the chamber 400 to re-pressurize the pressure inside the chamber 400 to the process pressure P1.

[0104] In this case, the aforementioned exhaust steps D42, D43 and first supply steps D52, D53 may be repeatedly performed.

[0105] Fig.11 This is equivalent to a diagram showing the degree of damage to the substrate when the substrate S is processed according to the conventional substrate processing method and the substrate processing method of the present invention. Fig.11 (A) shows the degree of damage of the substrate S according to the conventional substrate processing method, Fig.11 (B) shows the degree of damage of the substrate S according to the substrate processing method according to the present invention.

[0106] like Fig.11 As shown, it can be seen that in the case of the substrate S processed according to the conventional substrate processing method, damage occurs intensively in the center portion of the substrate S, and further, much damage also occurs overall.

[0107] On the contrary, it can be seen that in the case of the substrate S processed by the substrate processing method of the present invention, the damage of the central portion of the substrate S is significantly reduced, and further, the damage is relatively reduced as a whole compared to the existing method.

[0108] The above description is made with reference to the preferred embodiments of the present invention, but those skilled in the art may make various modifications and changes to the present invention without departing from the concept and scope of the present invention as described in the attached claims. Therefore, if the implementation of the modification basically includes the constituent elements of the claims of the present invention, it should be deemed that all of them belong to the technical scope of the present invention.

Claims

1. A substrate processing method, which is a substrate processing method of a substrate processing device, wherein the substrate processing device has a chamber that uses a fluid in a supercritical state to perform a processing process on the substrate, characterized in that: The substrate processing method comprises: a pressurizing step, supplying the fluid from below the chamber to pressurize the fluid to a preset process pressure; an isobaric step of supplying the fluid toward the chamber and discharging the fluid, thereby maintaining the pressure inside the chamber at a constant level and performing a treatment process on the substrate; and a decompression step of discharging the fluid from the interior of the chamber, During at least a portion of the pressure-equalizing step, the fluid is supplied to the chamber through a lower portion of the chamber.

2. The substrate processing method according to claim 1, characterized in that: The isobaric step comprises: a first supplying step of supplying the fluid to the chamber through a lower portion of the chamber; and The second supplying step is to supply the fluid to the chamber through an upper portion of the chamber.

3. The substrate processing method according to claim 2, characterized in that: The first supply step is arranged in a predetermined interval in the pressure equalization step.

4. The substrate processing method according to claim 2, characterized in that: In the pressure-equalizing step, the first supplying step and the second supplying step are repeated alternately.

5. The substrate processing method according to claim 1, characterized in that: In the isobaric step, the fluid is supplied to the chamber only through a lower portion of the chamber.

6. The substrate processing method according to claim 1, characterized in that: In the isobaric step, a pulse wave caused by the fluid is generated inside the chamber.

7. The substrate processing method according to claim 6, characterized in that: In the isobaric step, an exhaust step is performed to reduce the fluid inside the chamber to a preset pressure, and then a first supply step is performed to supply the fluid to the chamber through the bottom of the chamber to re-pressurize the pressure inside the chamber to the process pressure.

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