Substrate processing method, method for manufacturing semiconductor device, program, and substrate processing apparatus

Abstract

A technology is provided that can increase the number of substrates etched per unit time (production capacity) while suppressing the residue of components originating from the modified gas. The etching process includes, sequentially, the following steps: (a1) supplying a first modified gas to the substrate to form a first modified layer on at least a portion of the surface of a specified material on the substrate at a first rate; (a2) supplying a second modified gas with a molecular structure different from the first modified gas to the substrate to form a second modified layer on at least a portion of the surface of the specified material, including the first modified layer, at a second rate lower than the first rate; and (b) supplying a reactive gas that reacts with the second modified layer to the substrate to remove at least a portion of the second modified layer from the substrate.

Description

Technical Field

[0001] This disclosure relates to substrate processing methods, semiconductor device manufacturing methods and procedures, and substrate processing apparatus. Background Technology

[0002] As a process in the manufacturing of semiconductor devices, there are cases where a process is performed by supplying different gases a predetermined number of times to etch a predetermined material (e.g., a film-like material) (see, for example, Patent Document 1).

[0003] [Existing Technical Documents]

[0004] [Patent Literature]

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-158142 Summary of the Invention

[0006] (The problem that the invention aims to solve)

[0007] This disclosure provides a technique that can increase the number of substrates etched per unit time (production capacity) while suppressing the residue of components originating from modified gases.

[0008] (Methods used to solve problems)

[0009] The technology provided according to one aspect of this disclosure includes an etching process that sequentially begins the following steps:

[0010] (a1) A process of supplying a first modified gas to a substrate and forming a first modified layer on at least a portion of the surface of a specified material on the substrate at a first rate.

[0011] (a2) A step of supplying a second modifying gas with a molecular structure different from the first modifying gas to the substrate, and forming a second modified layer at a second rate lower than the first rate on at least a portion of the region including the first modified layer on the surface of the specified material; and

[0012] (b) A process of supplying a reactive gas that reacts with the second modified layer to the substrate and removing at least a portion of the second modified layer from the substrate.

[0013] The effects of the invention

[0014] According to this disclosure, the number of substrates etched per unit time (production capacity) can be increased while suppressing the residue of components originating from the modified gas. Attached Figure Description

[0015] Figure 1This is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus preferred for use in one embodiment of the present disclosure, showing the furnace portion in a longitudinal sectional view.

[0016] Figure 2 This is a schematic diagram of the controller of a substrate processing apparatus preferred in one embodiment of the present disclosure, and is a block diagram representing the control system of the controller.

[0017] Figure 3 This is a diagram illustrating an etching process according to one method of this disclosure.

[0018] Figure 4 This is a schematic diagram illustrating the change of a specified material on a substrate during an etching process according to one embodiment of the present disclosure.

[0019] Figure 5 (A) is a diagram illustrating a variation 1 of an etching process according to one aspect of the present disclosure. Figure 5 (B) is a diagram illustrating a variation 2 of an etching process according to one aspect of the present disclosure.

[0020] Figure 6 This is a diagram illustrating a variation 3 of the etching process of one embodiment of the present disclosure.

[0021] Figure 7 These are schematic diagrams illustrating the changes in a specified material on a substrate in variations 3 and 4 of an etching process according to one embodiment of the present disclosure.

[0022] Figure 8 This is a diagram of variation 4, illustrating an etching process according to one aspect of this disclosure. Detailed Implementation

[0023] <One way of this disclosure>

[0024] The following describes one method of this disclosure, mainly referring to... Figures 1 to 4 This explanation is provided below. Furthermore, the accompanying drawings used in this explanation are for illustrative purposes only, and the dimensional relationships and proportions of the components shown in the drawings may not necessarily match those of the actual product. Additionally, the dimensional relationships and proportions of components in multiple drawings may not be consistent with each other.

[0025] (1) Composition of the substrate processing apparatus

[0026] like Figure 1As shown, the processing furnace 202, which is a substrate processing apparatus, has a heater 207 as a heating mechanism (temperature adjustment unit). The heater 207 also has the function of an activation mechanism (excitation unit) that uses heat to activate (excite) gas. A reaction tube 203 is disposed inside the heater 207. A processing chamber 201 is formed in the hollow part of the reaction tube 203 to accommodate a wafer 200, which serves as a substrate. The wafer 200 is processed in this processing chamber 201. Nozzles 249a to 249c are provided in the processing chamber 201, penetrating the lower sidewall of the reaction tube 203. Gas supply pipes 232a to 232c are connected to the nozzles 249a to 249c, respectively.

[0027] In gas supply pipes 232a-232c, starting from the upstream side of the airflow, are sequentially provided: mass flow controllers (MFCs) 241a-241c serving as flow controllers (flow control units), and valves 243a-243c serving as switching valves. Gas supply pipe 232d is connected to gas supply pipe 232a downstream of valve 243a. Gas supply pipe 232e is connected to gas supply pipe 232b downstream of valve 243b. Gas supply pipe 232f is connected to gas supply pipe 232c downstream of valve 243c. In gas supply pipes 232d-232f, starting from the upstream side of the airflow, are sequentially provided MFCs 241d-241f and valves 243d-243f.

[0028] Nozzles 249a-249c are respectively positioned in a ring-shaped space between the inner wall of the reaction tube 203 and the wafer 200, and are arranged upright above the arrangement of the inner wall of the reaction tube 203, facing the wafer 200. Gas supply holes 250a-250c are respectively provided on the side of the nozzles 249a-249c. The gas supply holes 250a-250c open towards the center of the reaction tube 203, allowing gas to be supplied to the wafer 200. Multiple gas supply holes 250a-250c are provided from the lower part to the upper part of the reaction tube 203.

[0029] In this manner, gas is delivered (supplied) via nozzles 249a to 249c into the space defined by the inner wall of the sidewall of the reaction tube 203 and the ends (peripherals) of the multiple wafers 200 arranged within the reaction tube 203. Then, gas is supplied to the wafers 200 within the reaction tube 203 through gas supply holes 250a to 250d, which open in each of the nozzles 249a to 249c.

[0030] A first modified gas is supplied to the processing chamber 201 via gas supply pipe 232a, MFC 241a, valve 243a, and nozzle 249a. A second modified gas with a molecular structure different from the first modified gas is supplied to the processing chamber 201 via gas supply pipe 232b, MFC 241b, valve 243b, and nozzle 249b. A reaction gas that reacts with the first modified layer 400 and the second modified layer 500 (described later) is supplied to the processing chamber 201 via gas supply pipe 232c, MFC 241c, valve 243c, and nozzle 249c. Inactive gases are supplied to the processing chamber 201 via gas supply pipes 232d to 232f, MFCs 241d to 241f, valves 243d to 243f, gas supply pipes 232a to 232c, and nozzles 249a to 249c, respectively. Inactive gases function as flushing gases, carrier gases, dilution gases, etc.

[0031] The system mainly consists of gas supply pipe 232a, MFC 241a, and valve 243a, forming a first modified gas supply system for supplying the first modified gas. The system mainly consists of gas supply pipe 232b, MFC 241b, and valve 243b, forming a second modified gas supply system for supplying the second modified gas. The system mainly consists of gas supply pipe 232c, MFC 241c, and valve 243c, forming a reaction gas supply system for supplying the reaction gas. The system mainly consists of gas supply pipes 232d-232f, MFCs 241d-241f, and valves 243d-243f, forming an inactive gas supply system for supplying the inactive gas.

[0032] Below the side wall of the reaction tube 203, an exhaust pipe 231 is connected to exhaust the gas inside the processing chamber 201. A vacuum pump 246, serving as a vacuum exhaust device, is connected to the exhaust pipe 231 via a pressure sensor 245 (a pressure detector, or pressure detection unit) and an APC (Auto Pressure Controller) valve 244 (a pressure regulator, or pressure adjustment unit). The APC valve 244 can perform vacuum exhaust and stop vacuum exhaust by opening and closing the valve while the vacuum pump 246 is actuated. Furthermore, while the vacuum pump 246 is actuated, the valve opening is adjusted based on the pressure information detected by the pressure sensor 245, thus enabling pressure adjustment within the processing chamber 201. The exhaust system mainly consists of the exhaust pipe 231, the pressure sensor 245, and the APC valve 244. The vacuum pump 246 may also be included in the exhaust system.

[0033] Below the reaction tube 203, a sealing cover 219 is provided to hermetically seal the lower opening of the reaction tube 203. Below the sealing cover 219, a rotation mechanism 267 is provided to rotate the wafer cassette 217 (described later). The rotation shaft 255 of the rotation mechanism 267 passes through the sealing cover 219 and is connected to the wafer cassette 217. The rotation mechanism 267 is configured to rotate the wafer cassette 217, thereby rotating the wafer 200. The sealing cover 219 is configured to be lifted vertically using a wafer cassette lift 115, which serves as a lifting mechanism. The wafer cassette lift 115 is configured as a conveying device (transfer mechanism) that moves the wafer 200 into or out of the processing chamber 201 by lifting the sealing cover 219.

[0034] The wafer cassette 217, serving as a substrate support, horizontally supports multiple wafers 200, for example, 25 to 200 wafers, in multiple layers. At the bottom of the wafer cassette 217, a heat insulation plate 218 is horizontally supported in multiple layers. Furthermore, the numerical range expressions such as "25 to 200 wafers" in this disclosure refer to a range in which the lower and upper limits are included. Therefore, "25 to 200 wafers" means "more than 25 wafers and less than 200 wafers." The same applies to other related numerical ranges.

[0035] A temperature sensor 263, which functions as a temperature detector, is installed inside the reaction tube 203. By adjusting the output of the heater 207 based on the temperature information detected by the temperature sensor 263, a temperature distribution can be formed within the processing chamber 201 that is desired.

[0036] like Figure 2 As shown, the controller 121, serving as the control unit, is configured as a computer comprising a CPU (Central Processing Unit) 121a, RAM (Random Access Memory) 121b, a storage device 121c, and an I / O interface 121d. The RAM 121b, storage device 121c, and I / O interface 121d are configured to exchange data with the CPU 121a via an internal bus 121e. The controller 121 is connected to an input / output device 122, such as a touchpad. Furthermore, an external storage device 123 can be connected to the controller 121. Additionally, the substrate processing apparatus may be configured to have one control unit or multiple control units. That is, control for executing the substrate processing steps described later can be performed using one control unit or multiple control units. In this specification, the term "control unit" includes not only the case of one control unit but also the case of multiple control units.

[0037] The storage device 121c is composed of, for example, flash memory or HDD (Hard Disk Drive). Within the storage device 121c, a control program for controlling the operation of the substrate processing apparatus and a process recipe describing the steps and conditions of the etching process described later are readablely stored. The process recipe enables the controller 121 to execute each step of the etching process (etching treatment) described later, combining them in a manner that yields a predetermined result, and functions as a program (or program product). Hereinafter, the process recipe, control program, etc., will also be simply referred to as a "program (or program product)". Furthermore, the process recipe is also simply referred to as a "recipe". The term "program" is used in this specification in cases where only the recipe is included, cases where only the control program is included, or cases where both are included. RAM 121b is configured as a memory area (working block) that temporarily stores programs, data, etc., read by the CPU 121a.

[0038] I / O interface 121d is connected to the aforementioned MFC 241a~241f, valves 243a~243f, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotating mechanism 267, wafer box lift 115, etc.

[0039] CPU 121a reads and executes the control program from storage device 121c, and, in conjunction with operation command input from input / output device 122, can read the recipe from storage device 121c. CPU 121a is configured to control various gas flow adjustment actions performed by MFC 241a~241f, valve opening and closing actions of valves 243a~243f, APC valve opening and closing actions of APC valve 244, pressure adjustment actions of APC valve 244 based on pressure sensor 245, start and stop of vacuum pump 246, temperature adjustment actions of heater 207 based on temperature sensor 263, rotation and rotation speed adjustment actions of wafer cassette 217 performed by rotation mechanism 267, and lifting actions of wafer cassette 217 performed by wafer cassette elevator 115, etc., in accordance with the read recipe content.

[0040] The controller 121 is configured to install the aforementioned program stored in the external storage device 123 into a computer. The external storage device 123 includes, for example, a hard disk such as an HDD, an optical disk such as a CD, an optical disk such as an MO, or a semiconductor memory such as USB memory. The storage device 121c and the external storage device 123 constitute a computer-readable recording medium storing a program. Hereinafter, these will also be collectively referred to as "recording media." The term "recording media" is used in this specification in cases where only the storage device 121c is included, in cases where only the external storage device 123 is included, or in cases where both are included. Furthermore, when providing a program to a computer, the external storage device 123 may be omitted, and communication methods such as the Internet or dedicated lines may be used instead.

[0041] (2) Substrate processing process

[0042] Using the aforementioned processing furnace 202 as a step in the manufacturing process of a semiconductor device, an example of etching at least a portion of a predetermined material 300 formed on the surface of a wafer 200 is described. Figure 3 and Figure 4 The following description will explain the operation of each part of the processing furnace 202.

[0043] In this specification, the term "wafer" is used to refer to the wafer itself, and to a laminate of the wafer and a specified layer or film formed on its surface. The term "wafer surface" is used to refer to the surface of the wafer itself, and to the surface of a specified layer, etc., formed on the wafer. The phrase "forming a specified layer on the wafer" is used in the following ways: forming the specified layer directly on the surface of the wafer itself, and forming the specified layer on top of layers already formed on the wafer. The term "substrate" is used in the same way as "wafer" in this specification.

[0044] (Wafer loading and wafer cassette loading)

[0045] Multiple wafers 200, which have been formed with the specified material 300 for etching, are loaded into a wafer cassette 217 (wafer loading). Then, the wafer cassette 217, which supports multiple wafers 200, is lifted by a wafer cassette elevator 115 and moved into the processing chamber 201 (wafer loading).

[0046] (Pressure and temperature adjustment)

[0047] Vacuum pump 246 performs vacuum venting (pressure reduction venting) to achieve the required processing pressure (vacuum level) within processing chamber 201, i.e., the space where wafer 200 exists. Additionally, heater 207 heats the wafer 200 within processing chamber 201 to achieve the required processing temperature. Furthermore, rotation of wafer 200 begins by rotation mechanism 267. The operation of vacuum pump 246, heating of wafer 200, and rotation of wafer 200 are all continuously performed at least until the processing of wafer 200 is completed.

[0048] In this specification, "processing temperature" refers to the temperature of wafer 200 or the temperature inside processing chamber 201, and "processing pressure" refers to the pressure inside processing chamber 201. Furthermore, "processing time" refers to the duration of the processing. These terms also apply in the following descriptions.

[0049] Then, the following steps S11 to S16 are performed on the wafer 200 of the specified material 300 for which the etching object has been formed.

[0050] Examples of the 300 substances that can be etched include metal-containing substances such as metal oxides. Examples of metal elements contained in metal oxides include: aluminum (Al), zirconium (Zr), hafnium (Hf), titanium (Ti), yttrium (Y), lanthanum (La), tantalum (Ta), niobium (Nb), ruthenium (Ru), vanadium (V), zinc (Zn), manganese (Mn), cobalt (Co), indium (In), gallium (Ga), etc.

[0051] The etching rate of metal oxides tends to decrease. According to the technology disclosed herein, a modified layer can be formed at a higher modification rate even in metal oxides. This results in an increased etching rate. In the following description, the thickness of the modified layer formed per unit time is referred to as the "modification rate." Furthermore, the thickness of the modified layer removed per unit time is referred to as the "etching rate."

[0052] Examples of metal oxides include metal oxide films. Metal oxide films can also be films containing two or more of these metal elements. The techniques disclosed herein are particularly applicable when etching high-k films such as aluminum oxide (Al₂O₃), zirconium oxide (ZrO₂), hafnium oxide (HfO₂), titanium oxide (TiO₂), lanthanum oxide (La₂O₃), and tantalum oxide (Ta₂O₅).

[0053] The following explanation will focus on the case where the specified material 300 to be etched is a polycrystalline material composed of numerous crystalline particles. In polycrystalline materials, gaps easily form between the crystalline particles. In this case, the modification rate can vary significantly depending on the type of modifying gas.

[0054] If the modified layer is formed solely by a modifying gas with a high modification rate, it can be formed in a short time. However, the modified layer tends to form to depths that are difficult to remove by supplying reactant gases. Consequently, components originating from the modifying gas tend to remain in the membrane.

[0055] On the other hand, if the modified layer is formed using only a modifying gas with a low modification rate, the formation of the modified layer takes longer compared to using a modifying gas with a high modification rate. However, it is more difficult to form the modified layer to a depth that is difficult to remove by supplying a reactive gas. Therefore, components originating from the modifying gas are less likely to remain in the membrane.

[0056] According to the technology disclosed herein, after forming a first modified layer 400 using a first modified gas with a first modification rate of 1, a second modified layer 500 is formed using a second modified gas with a second modification rate of 2, lower than the first rate. Therefore, compared to the case where a modified layer of the same thickness is formed solely by the second modified gas, the time required for modified layer formation can be shortened. This increases production capacity. Furthermore, compared to the case where a modified layer of the same thickness is formed solely by the first modified gas, the formation of a modified layer deep within the specified material 300 can be suppressed. Therefore, the residue of components originating from the modified gas contained in the film can be suppressed.

[0057] Here, the region where the specified substance 300 is modified by the supply of the first modifying gas is referred to as the "first modified layer 400". Furthermore, the region where the specified substance 300, including at least the first modified layer 400, is modified by the supply of the second modifying gas is referred to as the "second modified layer 500". Additionally, one or both of the first and second modifying gases are referred to as "modifying gases". Furthermore, one or both of the first modified layer 400 and the second modified layer 500 are referred to as "modified layers".

[0058] Alternatively, when forming the modified layer, modification of the deep portion of the specified substance 300 may begin before sufficient modification is performed on the surface side of the specified substance 300 (or before the reaction of the modifying gas on the surface side of the specified substance 300). That is, a portion of the surface side and a portion of the deep side of the specified substance 300 may be modified simultaneously. Alternatively, when forming the modified layer, modification of the deep portion of the specified substance 300 may begin only after sufficient modification is performed on the surface side of the specified substance 300 (or after the reaction of the modifying gas on the surface side of the specified substance 300). That is, a portion of the surface side and a portion of the deep side of the specified substance 300 may not be modified simultaneously.

[0059] (First modified gas supply, step S11)

[0060] This step supplies a first modified gas to the wafer 200 within the processing chamber 201. Specifically, valve 243a is opened, allowing the first modified gas to flow into the gas supply pipe 232a. After the flow rate of the first modified gas is adjusted using MFC 241a, it is supplied to the processing chamber 201 via nozzle 249a and exhausted from the exhaust pipe 231. At this time, valves 243d to 243f are opened, allowing inactive gas to flow into the gas supply pipes 232d to 232f.

[0061] In this step, the first modified gas is supplied as follows: Figure 4 (A) shows a wafer 200 with a pre-defined material 300 for etching, as shown. Then, as... Figure 4 As shown in (B), at least a portion of the surface of a specified material 300 on wafer 200 is formed with a first modified layer 400 of a first thickness T1 at a first rate. Here, for example, the first modified layer 400 is a layer containing halogen elements such as F, which are components derived from the first modified gas. That is, at least a portion of the specified material 300 on wafer 200 is modified to contain a layer containing halogen elements derived from the first modified gas.

[0062] Here, the term "surface of the specified substance 300" includes the outermost surface of the specified substance 300 before the formation of the modified layer and the region deeper than this surface. Furthermore, the term "modified layer thickness" refers to the distance from the outermost surface of the modified layer to one end of the modified layer at its deeper side. Additionally, a "modified layer of specified thickness" may also contain unmodified specified substance 300 within a portion of the region from the outermost surface of the modified layer to the specified thickness.

[0063] In this step, the first modified layer 400, which has a predetermined thickness T1, is preferably formed under conditions where the supply time of the first modified gas is saturated. Furthermore, it is preferable to stop the supply of the first modified gas before the first thickness T1 of the first modified layer 400 reaches saturation, that is, before the first thickness T1 reaches a saturated first thickness H1 that limits the modification process using the first modified gas supply (e.g., no longer undergoes fluorination). This makes it easy to ensure that the first thickness T1 of the first modified layer 400 is a depth such that the modification layer cannot be removed using the supply of the reactant gas. As a result, residual components originating from the modified gas, such as halogen elements like F, in the predetermined substance 300 can be suppressed.

[0064] Furthermore, in this step, the first thickness T1 of the first modified layer 400 is preferably less than the self-limiting saturated second thickness H2 generated by the modification using the second modified gas supply in step S13 described later. Therefore, the first thickness T1 of the first modified layer 400 can easily become a depth that is insufficient for removing the modified layer using the reactive gas supply. This easily suppresses residual components originating from the modified gas in the specified substance 300, such as halogen elements like F.

[0065] In this step, the processing conditions for supplying the first modified gas can be exemplified as follows:

[0066] Processing temperature: 150~900℃, preferably 150~400℃

[0067] Processing pressure: 10~10000Pa, preferably 10~7000Pa

[0068] Gas supply time: 20~1200 seconds, preferably 20~1000 seconds

[0069] The partial pressure of the first modified gas is 10~5000Pa, preferably 10~3500Pa.

[0070] In addition, the processing temperature is set to be substantially the same in any of the steps described later.

[0071] In this disclosure, the term "supply time of a certain gas" refers to the time during which the gas is supplied to the wafer 200 or the processing chamber 201. Similarly, the term "processing partial pressure of a certain gas" refers to the partial pressure of the gas within the processing chamber 201. These terms also apply in the following description.

[0072] The first modifying gas can be a fluorine (F)-containing gas. The F-containing gas can be at least one of the following: fluorine (F2), nitrogen trifluoride (NF3), hydrogen fluoride (HF), carbon tetrafluoride (CF4), tungsten hexafluoride (WF6), chlorine trifluoride (ClF3), sulfur tetrafluoride (SF4), xenon difluoride (XeF2), etc. More than one of these can be used as the first modifying gas. Halogen elements such as F readily detach from the film. Therefore, it is difficult for halogen elements to remain in the specified substance 300 after etching.

[0073] Besides nitrogen (N2), inert gases can also include rare gases such as argon (Ar), helium (He), neon (Ne), and xenon (Xe). More than one of these can be used as an inert gas.

[0074] The first modified layer 400 formed in this step is a layer containing the elements contained in the first modified gas and the elements contained in the specified substance 300, such as a layer containing halogens. A halogen-containing layer is, for example, a fluoride-containing layer. For example, if the specified substance 300 is an Al₂O₃ film and the first modified gas is HF gas, the formed first modified layer is an aluminum fluoride layer (AlF layer). The AlF layer may also contain O or H.

[0075] (Exhaust, step S12)

[0076] When valve 243a is closed, the supply of the first modified gas is stopped. At this time, the APC valve 244 of the exhaust pipe 231 remains open, and vacuum exhaust is performed on the processing chamber 201 using the vacuum pump 246. This removes residual gases, such as unreacted first modified gas and reaction byproducts remaining on the wafer 200 and / or in the processing chamber 201, from the processing chamber 201. Alternatively, while valves 243d to 243f remain open, inactive gases can be continuously supplied to the processing chamber 201 to flush it. The inactive gas acts as a flushing gas, improving the effectiveness of removing residual gases from the wafer 200.

[0077] In this step, it is preferable to perform vacuum degassing and rinsing within the processing chamber 201, which serves as the space where the wafer 200 exists. This reduces the amount of components originating from the modified gas contained in the specified material 300 after etching.

[0078] The conditions for vacuum exhaust in this step can be illustrated as follows:

[0079] Processing pressure: 10~200Pa,

[0080] Processing time: 10~180 seconds.

[0081] The rinsing conditions for this step can be illustrated as follows:

[0082] Processing pressure: 10~7000Pa,

[0083] Processing time: 30~180 seconds.

[0084] (Second modified gas supply, step S13)

[0085] In this step, a second modified gas is supplied to the wafer 200 within the processing chamber 201. Specifically, valve 243b is opened, allowing the second modified gas to flow into the gas supply pipe 232b. The flow rate of the second modified gas is adjusted using MFC 241b, and it is supplied to the processing chamber 201 via nozzle 249b and exhausted from the exhaust pipe 231. At this time, valves 243d to 243f are opened, allowing inactive gas to flow into the gas supply pipes 232d to 232f.

[0086] In this step, the second modified gas is supplied as follows: Figure 4 (B) shows a wafer 200 on which at least a portion of the surface of a specified material 300 has formed a first modified layer 400. Furthermore, as shown... Figure 4As shown in (C), a second modified layer 500 is formed at a second rate lower than the first rate in a region on the surface of a specified material 300 on wafer 200 that contains at least a first modified layer 400. That is, the second modified layer 500 is formed in at least a portion of the region where the first modified layer 400 has been formed. Specifically, the second modified layer 500 contains regions where the specified material 300 is modified using a second modified gas, as well as regions where the first modified layer 400 is modified using a second modified gas. Additionally, a portion of the second modified layer 500 may also contain unmodified specified material 300 and the first modified layer 400.

[0087] In this way, by supplying the second modifying gas to the area where the first modified layer 400 of the specified material 300 has been formed, the time required to form the second modified layer 500 of the same thickness can be shortened compared to the case where the second modifying gas is supplied to the area where the first modified layer 400 of the specified material 300 has not been formed. As a result, the throughput of the etching process can be increased.

[0088] That is, in this step, the second thickness T2 of the second modified layer 500 formed in this step is made to be greater than the first thickness T1 of the first modified layer 400 formed in step S11. Therefore, it is more difficult to form a modified layer to a depth that makes it difficult to remove the modified layer by supplying a reactive gas.

[0089] In this step, the second thickness T2 of the second modified layer 500 is preferably formed under conditions where the supply time of the second modifying gas is saturated. Furthermore, it is preferable to stop supplying the second modifying gas if the second thickness T2 reaches saturation, that is, if the second thickness T2 has reached a second saturation thickness H2 that self-limits modification using the second modifying gas supply. Thus, by preventing the first modified layer 400 from reaching the first saturation thickness H1 in step S11, but allowing the second modified layer 500 to reach the second saturation thickness H2, the thickness of the modified layer can be easily made to a depth that is difficult to remove by supplying the reactive gas. Additionally, by saturating the second thickness T2, the thickness of the modified layer can be easily and precisely controlled, and the thickness of the specified substance 300 that can be removed in a single etching process can be easily controlled.

[0090] Furthermore, in this step, it is preferable to set the thickness of the second modified layer 500, i.e., the third thickness T3, formed in the region where the first modified layer 400 has not yet formed, to be less than or equal to the first thickness T1 of the first modified layer 400 formed in step S11. In this step, the modification rate in the region with the third thickness T3 formed using the second modified gas supply is lower than the modification rate in the region with the first thickness T1 formed using the second modified gas supply. Therefore, by making the third thickness T3 less than or equal to the first thickness T1, the time required to form the second modified layer 500 can be further shortened.

[0091] The processing conditions for supplying the second modified gas in this step can be illustrated as follows:

[0092] Processing temperature: 150~900℃, preferably 150~400℃.

[0093] Processing pressure: 10~10000Pa, preferably 10~7000Pa.

[0094] Gas supply time: 20~1200 seconds, preferably 20~1000 seconds.

[0095] The partial pressure of the second modified gas is 10~5000Pa, preferably 10~3500Pa.

[0096] The second modifying gas can be an F-containing gas with a molecular structure different from the first modifying gas. For example, the second modifying gas can be an F-containing gas with a molecular structure different from the first modifying gas, as exemplified by the first modifying gas. Halogen elements such as F readily detach from the film. Therefore, after etching, it is difficult for halogen elements to remain in the specified substance 300.

[0097] Furthermore, the second modifying gas is preferably a gas with a molecular size larger than that of the first modifying gas. This allows the second modified layer 500 to be easily formed at a second rate lower than the first rate. For example, when the first modifying gas is HF, the second modifying gas can be NF3, a gas with a molecular size larger than HF. This will be explained below.

[0098] When the specified substance 300 is a polycrystalline substance, there will be gaps with a small width-to-depth ratio and gaps with a large width-to-depth ratio within the specified substance 300. Here, "large gap width-to-depth ratio" refers to one or both of the gap entrance being narrower and the gap being deeper.

[0099] The first modifying gas, with its smaller molecular size, can easily reach deep into gaps with a larger width-to-depth ratio. Therefore, the modification rate of the first modifying gas is higher than that of the second modifying gas, and it reaches self-limiting saturation in a shorter time. Even in deep areas where removal of the modified layer by supplying a reactive gas is difficult, a modified layer can easily form. Therefore, when etching with the first modifying gas and the reactive gas, compared to using the second modifying gas, components originating from the modifying gas, such as halogen elements like F, are more likely to remain in the specified material 300.

[0100] In contrast, the second modifying gas, with a molecular size larger than the first modifying gas, struggles to penetrate deep into the gaps with a large width-to-depth ratio. Therefore, the modification rate of the second modifying gas is lower than that of the first modifying gas, resulting in a longer time to reach self-limiting saturation. Consequently, it is more difficult to form a modified layer in deeper areas where removal of the modified layer by supplying a reactive gas is challenging. Therefore, when etching with the second modifying gas and the reactive gas, compared to using the first modifying gas, it is less likely for halogen elements such as F, derived from the modifying gas, to remain in the specified substance 300.

[0101] According to the technology disclosed herein, after supplying a first modifying gas with a smaller molecular size, a second modifying gas with a larger molecular size is then supplied. This increases the modification rate, and the modification using the first and second modifying gases is less likely to reach the deeper layers of the specified substance 300. Consequently, residual components originating from the modifying gases, such as halogens like F, in the specified substance 300 can be suppressed.

[0102] The second modified layer 500 formed in this step contains elements contained in the second modified gas and elements contained in the specified substance 300, such as a layer containing halogens. Alternatively, the second modified layer 500 may also contain elements contained in the first modified gas. For example, a halogen-containing layer may contain fluorides. For instance, when the specified substance 300 is an Al₂O₃ film, the first modified gas is HF gas, and the second modified gas is NF₃ gas, an AlF layer is formed as the second modified layer 500. The AlF layer may also contain O or H. Halogens such as F readily detach from the film. Therefore, after etching, it is difficult for halogens to remain in the specified substance 300.

[0103] (Exhaust, step S14)

[0104] Close valve 243b to stop the supply of the second modified gas. Then, perform vacuum venting and / or rinsing in the processing chamber 201 according to the same steps and conditions as in step S12. This removes residual gases, such as unreacted second modified gas and reaction byproducts remaining on the wafer 200 and / or in the processing chamber 201, from the processing chamber 201.

[0105] (Reaction gas supply, step S15)

[0106] Next, reactive gas is supplied to the wafer 200 inside the processing chamber 201. Specifically, valve 243c is opened, allowing reactive gas to flow into the gas supply pipe 232c. The flow rate of the reactive gas is adjusted using MFC 241c, and it is supplied to the processing chamber 201 via nozzle 249c and exhausted from the exhaust pipe 231. At this time, valves 243d to 243f are opened, allowing inactive gas to flow into the gas supply pipes 232d to 232f.

[0107] This step involves supplying the reaction gas that reacts with the second modified layer 500, such as... Figure 4 (C) shows a wafer 200 on which a second modified layer 500 has been formed on the surface of a specified material 300. Thus, as shown... Figure 4 As shown in (D), at least a portion of the second modified layer 500 on the surface of the specified material 300 on the wafer 200 is removed. That is, this step can remove at least a portion of the specified material 300 on the wafer 200. At this time, a portion of the second modified layer 500 may not be removed from the wafer 200.

[0108] The processing conditions for supplying the reactant gas in this step can be illustrated as follows:

[0109] Processing pressure: 10~7000Pa, preferably 10~3000Pa.

[0110] Gas supply time: 20~1200 seconds, preferably 20~1000 seconds.

[0111] The partial pressure of the reactant gas is 10~4000 Pa, preferably 10~1500 Pa.

[0112] The reaction gas can be, for example, chlorine (Cl2) gas, or a Cl-containing gas containing a specified element and chlorine (Cl). The specified element can be, for example, one or more of the following: boron (B), carbon (C), sulfur (S), phosphorus (P), titanium (Ti), silicon (Si), aluminum (Al), tin (Sn). These gases containing the specified element and Cl can be, for example, boron trichloride (BCl3), carbon tetrachloride (CCl4), thionyl chloride (SOCl2), sulfonyl chloride (SO2Cl2), phosgene (COCl2), phosphorus trichloride (PCl3), phosphorus pentachloride (PCl5), titanium tetrachloride (TiCl4), silicon tetrachloride (SiCl4), dimethylaluminum chloride (C2H6AlCl), etc.

[0113] (Exhaust, step S16)

[0114] Close valve 243c to stop the supply of reaction gas. Then, perform vacuum venting and / or rinsing of the processing chamber 201 according to the same steps and conditions as in step S12 or step S14. This removes residual gases, such as unreacted reaction gases and reaction byproducts remaining on the wafer 200 and / or in the processing chamber 201, from the processing chamber 201.

[0115] By sequentially performing the above steps S11 to S16, at least a portion of the specified material 300 on the wafer 200 can be removed (also known as "etching").

[0116] (Post-rinse and return to atmospheric pressure)

[0117] Inactive gases are supplied into the processing chamber 201 from gas supply pipes 232d to 232f, and exhaust gases are discharged from exhaust pipe 231. This flushes the processing chamber 201, removing residual gases and reaction byproducts (post-flushing). Then, the environment inside the processing chamber 201 is replaced with inactive gases (inactive gas replacement), and the pressure inside the processing chamber 201 is brought back to atmospheric pressure.

[0118] (Wafer box unloading and wafer release)

[0119] Then, the sealing cover 219 is lowered using the wafer cassette lifter 115, and the lower end of the reaction tube 203 is opened. Then, the processed wafer 200, supported by the wafer cassette 217, is removed from the lower end of the reaction tube 203 (wafer cassette unloading). The processed wafer 200 is then removed from the wafer cassette 217 (wafer release).

[0120] Furthermore, in steps S11, S13, and S15 described above, the activation of the first modifying gas, the second modifying gas, and the reactive gas using plasma is not performed. According to the technology of this disclosure, the time required for the formation of the modified layer can be shortened without using plasma. Therefore, plasma-induced degradation of the specified material 300 formed on the wafer 200 can be suppressed, and the etching rate can be increased. Alternatively, in one or more of steps S11, S13, and S15 described above, the first modifying gas, the second modifying gas, and the reactive gas can be activated using plasma. In this case, at least some of the effects of this disclosure can still be obtained.

[0121] <Other methods of this disclosure>

[0122] The above provides a detailed explanation of the methods used in this disclosure. However, this disclosure is not limited to the methods described above, and various modifications may be made without departing from the main theme.

[0123] (Variation Example 1)

[0124] Figure 5 (A) represents the process flow of a modified example 1 of the etching process disclosed herein.

[0125] In this variation, although steps S11 to S16 are performed sequentially, the timing of the start of supplying the second modified gas in step S13 differs from the above method. That is, step S12 is omitted, and the second modified gas is supplied before the first modified gas supply ends. Then, the supply of the second modified gas ends after the first modified gas supply ends. This variation achieves the same effect as the above method. Furthermore, this variation further shortens the time required for the formation of the modified layer, thus increasing the throughput of the etching process.

[0126] (Variation Example 2)

[0127] Figure 5 (B) shows the process flow of a modified example 2 of the etching process of this disclosure.

[0128] In this variation, although steps S11 to S16 are performed sequentially, the timing of the start of supplying the second modified gas in step S13 differs from the above method. That is, step S12 is omitted, and the supply of the second modified gas begins simultaneously with the end of the supply of the first modified gas. This variation achieves the same effect as the above method. Furthermore, this variation can further shorten the time required for the formation of the modified layer, thereby increasing the throughput of the etching process.

[0129] (Variation Example 3)

[0130] Figure 6 This describes the process of variation 3.

[0131] In this modified example, after performing a first etching process in which steps S11 to S16 are repeated for the first number of times (n times, where n is an integer of 1 or 2 or more), a second etching process is performed in which steps S11 to S16 are repeated for the second number of times (m times, where m is an integer of 1 or 2 or more). Here, the supply time of the first modified gas in step S11 of the first etching process is set as the first time, and the supply time of the first modified gas in step S11 of the second etching process is set as the second time, which is shorter than the first time. This modified example can also achieve the same effect as described above.

[0132] That is, in the second etching process, the supply time of the first modifying gas, which has a higher modification rate, is set to be shorter than the supply time of the first modifying gas in the first etching process. In this case, since the first modified layer can be thicker than in the second etching process in the first etching process, it is easier to form the second modified layer. Therefore, production capacity can be improved. In addition, since the first modified layer can be made thinner than in the first etching process in the second etching process, it is more difficult to form the modified layer to a depth that is difficult to remove using the supply of reactive gas. Therefore, it is less likely that components originating from the modifying gas will remain in the specified material 300 after the etching process is completed.

[0133] The following uses Figure 7 Another preferred embodiment of Modification 3 will be described below. Figure 7 (A) is a schematic diagram of a wafer 200 on which the specified material 300 of the etched object has been formed. Figure 7 (B) is a schematic diagram of the specified material 300 on the wafer 200 after the first etching process. Figure 7(C) is a schematic diagram of the specified material 300 on the wafer 200 after the second etching process.

[0134] In the first etching step, it is preferable that the thickness T2 of the second modified layer 500 formed in the first etching step is less than the thickness T1 of the first modified layer 400 formed in the first etching step. In this case, since the second modified layer 500 can be entirely formed within the first modified layer 400, the time required to form the modified layer in the first etching step can be further shortened. However, in this case, if... Figure 7 As shown in (B), a first modified layer 400 with a thickness of TX exists on the surface of the specified material 300 at the end of the first etching process.

[0135] In this case, in the second etching process, it is preferable to set the thickness T4 of the second modified layer 500 formed in the second etching process to be greater than the thickness T3 of the first modified layer 400 formed in the second etching process. This reduces the impact of components originating from the first modified gas remaining in the specified material 300 from the first etching process. That is, it further improves productivity and further reduces impurities in the specified material 300 after the etching process. Furthermore, for example, by extending the supply time of the first and second modified gases in the second etching process, the thicknesses T3 of the first modified layer 400 and T4 of the second modified layer 500 formed in the second etching process can be increased, respectively.

[0136] Furthermore, in this case, it is preferable that the second etching process removes a region of the specified material 300 that is at least deeper than the deepest part of the first modified layer 400 with a thickness of TX. In other words, in the second etching process, it is preferable that, at the end of the first etching process, the region of the specified material 300 that is deeper than the deepest part of the first modified layer 400 present on the surface of the specified material 300 is removed from the wafer 200. This improves throughput and further reduces impurities in the specified material 300 after the etching process.

[0137] (Variation Example 4)

[0138] Figure 8 This describes the process of variation 4.

[0139] In this modified example of the etching process, after performing the third etching process, which involves sequentially performing steps S11 to S16 for the third time (p times, where p is an integer of 1 or 2 or more), a fourth etching process is performed, which involves sequentially performing steps S13 to S16 for the fourth time (q times, where q is an integer of 1 or 2 or more). This modified example can also achieve the same effect as described above.

[0140] That is, the fourth etching process does not include supplying the first modifying gas, which has a higher modification rate. In this case, since a thicker first modified layer can be formed in the third etching process than in the fourth etching process, the formation of the second modified layer is easier. Therefore, production capacity can be improved. In addition, since the first modified gas is not supplied in the fourth etching process, at least a portion of the first modified layer formed using the first modified gas supply in the third etching process can be removed in the fourth etching process. Therefore, it is difficult for components originating from the modifying gas to remain in the specified material 300 after the etching process is completed.

[0141] The following uses Figure 7 Another preferred embodiment of Modification 4 will be described below.

[0142] In the third etching step, it is preferable that the thickness T2 of the second modified layer 500 formed in the third etching step is less than the thickness T1 of the first modified layer 400 formed in the third etching step. In this case, since the second modified layer 500 can be entirely formed within the first modified layer 400, the time required for the third etching step to form the modified layer can be further shortened. However, in this case, if... Figure 7 As shown in (B), a first modified layer 400 with a thickness of TX exists on the surface of the specified material 300 at the end of the third etching process.

[0143] In this case, the fourth etching process preferably removes a region of the specified material 300 that is at least deeper than the deepest part of the first modified layer 400 with a thickness of TX. In other words, in the fourth etching process, it is preferable to remove the region of the specified material 300 that is deeper than the deepest part of the first modified layer 400 present on the surface of the specified material 300 from the wafer 200 at the end of the third etching process. This improves throughput and further reduces impurities in the specified material 300 after the etching process is completed.

[0144] In modifications 3 and 4, the thickness T1 of the first modified layer 400 formed in the first and third etching steps can also be saturated. In this case, the time required to form the second modified layer 500 in the first and third etching steps can be further shortened. Alternatively, in modifications 3 and 4, the thickness T1 of the first modified layer 400 formed in the first and third etching steps may not be saturated. In this case, the first modified layer 400 present on the surface of the specified material 300 at the end of the first and third etching steps can be thinned. Therefore, even if the etching amount in the second etching step is set to be small, impurities in the specified material 300 after the etching step is completed can be reduced.

[0145] In variations 3 and 4, the thickness T2 of the second modified layer 500 formed in the first and third etching processes can be set to be greater than the thickness T1 of the first modified layer 400 formed in the first etching process. In this case, at least some of the above-mentioned effects can also be obtained.

[0146] (Other methods)

[0147] The above method is described using etching as an example of a process performed on a film formed on wafer 200. However, this disclosure is not limited to this. For example, the technique of this disclosure can also be applied to etching processes performed on films formed on the inner wall of processing chamber 201 or on the surface of wafer cassette 217 (cleaning processes within processing chamber 201). Furthermore, for example, the technique of this disclosure can also be applied to cases where a film is formed on wafer 200 within processing chamber 201, and then etched onto that film within processing chamber 201. These methods can achieve the same effects as the methods described above.

[0148] The specified material 300, which is the object to be etched, can also be a material other than a metal oxide. For example, the specified material 300 can also be a metal film. For example, the metal film can also be a film substantially composed of metal elements such as cobalt (Co), copper (Cu), iron (Fe), molybdenum (Mo), nickel (Ni), and tungsten (W). In addition, the specified material 300 can also be a semiconductor film. For example, the semiconductor film can also be a film substantially composed of semiconductor elements such as silicon (Si) and germanium (Ge). Furthermore, the specified material 300 can also be an indium-gallium-arsenic (InGaAs) film, an indium-aluminum-arsenic (InAlAs) film, an indium-gallium-zirconium-oxygen (InGaZrO4) film, a silicon nitride (SiN) film, or a titanium nitride (TiN) film. In these cases, at least some of the effects described above can also be obtained.

[0149] The first and second modifying gases can also be substances other than those containing sulfur (F). For example, the first and second modifying gases can be gases containing sulfur (Cl), oxidizing gases, or gases containing organic ligands. For example, oxidizing gases can be oxygen (O2), ozone (O3), water vapor (H2O), and mixtures of hydrogen (H2) and O2. Gases containing organic ligands can be trimethylaluminum gas, acetylacetone (Hacac) gas, dimethylacetamide gas, tin(II) acetylacetone (Sn(acac)2) gas, or hexafluoroacetylacetone (Hhfac) gas. Furthermore, the reacting gas can also be substances other than those containing sulfur (Cl). For example, the reacting gas can be any of the aforementioned gases containing sulfur (F), oxidizing gases, or gases containing organic ligands. The first modifying gas, the second modifying gas, and the reacting gas can be selected from the aforementioned gases in conjunction with the specified substance 300 for etching. In this case, at least some of the aforementioned effects can be obtained.

[0150] The formulations used in substrate processing are prepared separately according to the processing requirements, and preferably stored in the storage device 121c in advance via an electrical communication line and an external storage device 123. Then, when substrate processing begins, the CPU 121a preferably selects an appropriate formulation from the multiple formulations stored in the storage device 121c according to the processing requirements. As a result, various processing methods can be performed with good reproducibility for films of various types, compositions, qualities, and thicknesses using the substrate processing apparatus. In addition, the operator's workload is reduced, operational errors are avoided, and substrate processing can be started quickly.

[0151] The above-mentioned formula is not limited to newly made cases; for example, it can also be prepared by modifying an existing formula already installed in the substrate processing apparatus. In the case of modifying the formula, the modified formula can also be installed in the substrate processing apparatus via an electrical communication line and a recording medium for recording the formula. Alternatively, the existing formula already installed in the substrate processing apparatus can be directly modified by manipulating the input / output device 122 provided in the existing substrate processing apparatus.

[0152] The above description pertains to a batch substrate processing apparatus that processes multiple substrates at a time. This disclosure is not limited to the above methods; it is also applicable, for example, to a monolithic substrate processing apparatus that processes one or more substrates at a time. Furthermore, the above description pertains to a substrate processing apparatus equipped with a hot-walled processing furnace. This disclosure is not limited to the above methods; it is also applicable, for example, to a substrate processing apparatus equipped with a cold-walled processing furnace.

[0153] When using these substrate processing apparatuses, processing can be performed according to the same processing procedures and processing conditions as described above and in the modified examples, and the same effects as described above and in the modified examples can be obtained.

[0154] The above methods and variations can be used in combination as appropriate. In this case, the processing steps and conditions can be set to be the same as those of the above methods and variations.

[0155] Symbol Explanation

[0156] 200: Wafer (substrate)

[0157] 300: Specified Substances

[0158] 400: First Modification Layer

[0159] 500: Second Modification Layer

Claims

1. A substrate processing method, characterized in that, This includes the etching process, which sequentially begins with the following steps: (a1) A process of supplying a first modified gas to a substrate and forming a first modified layer on at least a portion of the surface of a specified material on the substrate at a first rate. (a2) A step of supplying a second modifying gas with a molecular structure different from the first modifying gas to the substrate, and forming a second modified layer at a second rate lower than the first rate on at least a portion of the region including the first modified layer on the surface of the specified material; and (b) A process of supplying a reactive gas that reacts with the second modified layer to the substrate and removing at least a portion of the second modified layer from the substrate.

2. The substrate processing method according to claim 1, characterized in that, In the above etching process, (a2) begins before (a1) ends or at the same time as (a1) ends.

3. The substrate processing method according to claim 1, characterized in that, The above etching process includes: The first etching process begins sequentially with steps (a1), (a2), and (b), and the supply time of the first modified gas in (a1) is set as the first time; and The second etching process begins sequentially with steps (a1), (a2), and (b), and the supply time of the first modified gas in (a1) is set to a second time that is shorter than the first time. In the above etching process, after the first etching process is performed for the first time, the second etching process is performed for the second time.

4. The substrate processing method according to claim 1, characterized in that, The above etching process includes: The third etching process begins sequentially with (a1), (a2), and (b); and The fourth etching process includes (a2) and (b), but excludes (a1). In the above etching process, after the third etching process is performed for the third time, the fourth etching process is performed for the fourth time.

5. The substrate processing method according to any one of claims 1 to 4, characterized in that, The thickness of the second modified layer formed in (a2) is greater than the thickness of the first modified layer formed in (a1).

6. The substrate processing method according to any one of claims 1 to 4, characterized in that, In (a1), the first modified layer of the first thickness is formed under conditions where the supply time of the first modified gas is saturated. The process ends before the first thickness saturation (a1).

7. The substrate processing method according to claim 6, characterized in that, In (a2), the second modified layer of the second thickness is formed under conditions where the supply time of the second modified gas is saturated. The process ends after the second thickness saturation described above (a2).

8. The substrate processing method according to claim 7, characterized in that, Make the first thickness less than the thickness when the second thickness is saturated.

9. The substrate processing method according to claim 7, characterized in that, In (a2), the thickness of the second modified layer formed in the region where the first modified layer is not formed, i.e., the third thickness, is less than or equal to the first thickness.

10. The substrate processing method according to claim 3, characterized in that, The thickness of the second modified layer formed in the first etching process is less than the thickness of the first modified layer formed in the first etching process. The thickness of the second modified layer formed in the second etching process (a2) is greater than the thickness of the first modified layer formed in the second etching process (a1).

11. The substrate processing method according to claim 10, characterized in that, In the second etching process described above, the specified material in a region deeper than the deepest part of the first modified layer that exists on the surface of the specified material at the end of the first etching process described above is removed from the substrate.

12. The substrate processing method according to claim 4, characterized in that, The thickness of the second modified layer formed in the third etching process is less than the thickness of the first modified layer formed in the third etching process. In the fourth etching process described above, the specified material in a region deeper than the deepest part of the first modified layer that exists on the surface of the specified material at the end of the third etching process described above is removed from the substrate.

13. The substrate processing method according to any one of claims 1 to 4, characterized in that, The first modified gas and the second modified gas mentioned above are fluorine-containing gases. The first modified layer and the second modified layer mentioned above are layers containing fluorides.

14. The substrate processing method according to any one of claims 1 to 4, characterized in that, The substances specified above are metal oxides.

15. The substrate processing method according to any one of claims 1 to 4, characterized in that, The molecular size of the second modified gas is made larger than that of the first modified gas.

16. The substrate processing method according to any one of claims 1 to 4, characterized in that, The aforementioned substances are polycrystalline substances.

17. The substrate processing method according to any one of claims 1 to 4, characterized in that, In (a1) and (a2), the activation of the first modified gas and the second modified gas using plasma is not performed.

18. A method for manufacturing a semiconductor device, characterized in that, This includes the etching process, which sequentially begins with the following steps: (a1) A process of supplying a first modified gas to a substrate and forming a first modified layer on at least a portion of the surface of a specified substance on the substrate at a first rate. (a2) A step of supplying a second modifying gas with a molecular structure different from the first modifying gas to the substrate, and forming a second modified layer at a second rate lower than the first rate on at least a portion of the region including the first modified layer on the surface of the specified material; and (b) A process of supplying a reactive gas that reacts with the second modified layer to the substrate and removing at least a portion of the second modified layer from the substrate.

19. A program that uses a computer to cause a substrate processing apparatus to perform an etching step, characterized in that, The etching process begins with the following steps in sequence: (a1) The step of supplying a first modified gas to a substrate and forming a first modified layer on at least a portion of the surface of a specified substance on the substrate at a first rate; (a2) The step of supplying a second modifying gas with a molecular structure different from the first modifying gas to the substrate, and forming a second modified layer at a second rate lower than the first rate on at least a portion of the region including the first modified layer on the surface of the specified material; and (b) The step of supplying a reactive gas that reacts with the second modified layer to the substrate and removing at least a portion of the second modified layer from the substrate.

20. A substrate processing apparatus, characterized in that, have: A first modified gas supply system supplies a first modified gas to at least a portion of the surface of a specified substance on a substrate to form a first modified layer. The second modified gas supply system supplies a second modified gas with a molecular structure different from the first modified gas described above, and forms a second modified layer on at least a portion of the surface of the specified substance. A reaction gas supply system that supplies the reaction gas that reacts with the second modified layer described above; and The control unit is configured to control the first modified gas supply system, the second modified gas supply system, and the reaction gas supply system to perform an etching process in which the following processes are initiated sequentially: (a1) A process of supplying the first modified gas to the substrate and forming a first modified layer on at least a portion of the surface of the specified material at a first rate. (a2) A process in which the second modified gas is supplied to the substrate, and a second modified layer is formed on at least a portion of the surface of the specified material, including the first modified layer, at a second rate lower than the first rate; and (b) A process of supplying the above-mentioned reactive gas to the above-mentioned substrate and removing at least a portion of the above-mentioned second modified layer from the above-mentioned substrate.

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