SUBSTRATE PROCESSING METHOD, SEMICONDUCTOR DEVICE MANUFACTURING METHOD, SUBSTRATE PROCESSING APPARATUS, AND PROGRAM

Abstract

To provide a technology for improving control of etching amount. [Solution] The first film is etched by performing a predetermined number of non-simultaneous cycles of: (a) supplying a first gas to the substrate to form a first modified layer on at least a portion of the surface of a first film exposed on the surface of the substrate; and (b) supplying a second gas having a molecular structure different from that of the first gas to the substrate to at least one of reacting the second gas with the first modified layer and activating the first modified layer with the second gas to generate etching species, and etching at least a portion of the first film with these etching species.

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a semiconductor device, a substrate processing apparatus, and a program. [Background technology]

[0002] 2. Description of the Related Art As one step in the manufacturing process of a semiconductor device, a process of etching a film exposed on the surface of a substrate is often performed (see, for example, Patent Document 1).

[0003] As semiconductor devices are scaled, the processing dimensions are becoming finer and more complex, which requires the repeated high-precision patterning process including the above-mentioned etching process, which is one of the reasons for the increase in costs. In response to this, there is a technology for performing the above-mentioned etching process at the atomic layer level (hereinafter also referred to as atomic layer etching), and such a process with high controllability has attracted attention as a useful technology for reducing the number of steps. Conventionally, the technology related to atomic layer etching has mainly been a method using plasma. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-160962 A Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional film etching using etching gas, the amount of etching depends on the partial pressure (≒supply amount) of the etching gas. Therefore, the amount of etching differs due to the gas pressure distribution in the reaction system. For example, when etching a film formed inside a groove, even with the same process time, the amount of etching is less for a film formed at the bottom of a deep groove where gas is difficult to supply compared to a film formed near the opening of the groove where gas is easily supplied. Thus, conventional film etching using etching gas has had problems with the controllability of the amount of etching.

[0006] Therefore, an object of the present disclosure is to provide a technique for improving controllability of the etching amount. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, (a) supplying a first gas to a substrate to form a first modified layer on at least a portion of a surface of a first film exposed on the substrate; (b) supplying a second gas having a molecular structure different from that of the first gas to the substrate to react the second gas with the first modified layer and / or activating the first modified layer with the second gas to generate etching species, and etching at least a portion of the first film with the etching species; A technique is provided for etching the first film by performing a predetermined number of non-simultaneous cycles. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a technique for improving controllability of the etching amount. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus suitably used in one embodiment of the present disclosure, showing a processing furnace 202 portion in vertical cross section. [Diagram 2]FIG. 2 is a schematic configuration diagram of a vertical processing furnace of a substrate processing apparatus preferably used in one embodiment of the present disclosure, showing a processing furnace 202 portion in a cross-sectional view taken along line AA in FIG. [Diagram 3] FIG. 3 is a schematic configuration diagram of a controller 121 of a substrate processing apparatus suitably used in one embodiment of the present disclosure, and is a block diagram showing a control system of the controller 121. [Figure 4] FIG. 4 is a diagram showing a gas supply sequence of an etching process according to one embodiment of the present disclosure. [Diagram 5]FIG. 5(a) is a partial enlarged cross-sectional view of the wafer 200 in a state where the first gas 10 is supplied to the wafer 200 with the base 200a exposed on the surface, and the first gas 10 is adsorbed on the surface of the base 200a to form a first modified layer 200b. FIG. 5(b) is a partial enlarged cross-sectional view of the wafer 200 in a state where the second gas 20 is supplied to the wafer 200 with the first modified layer 200b formed. FIG. 5(c) is a partial enlarged cross-sectional view of the wafer 200 in a state where the first modified layer 200b is activated by the second gas 20 and the etching species 200c is generated. FIG. 5(d) is a partial enlarged cross-sectional view of the wafer 200 in a state where a part of the surface of the base 200a is etched by the etching species 200c, and a first product 12 and a second product 14 are generated during the etching. FIG. 5(e) is a partial enlarged cross-sectional view of the wafer 200 showing the behavior of the first product 12 and the second product 14 on the surface of the base 200a, the surface of which has been partially etched. FIG. 5(f) is a partial enlarged cross-sectional view of the wafer 200 in a state in which the second product 14 remains and / or is adsorbed on the surface of the base 200a, the surface of which has been partially etched. FIG. 5(g) is a partial enlarged cross-sectional view of the wafer 200 in a state in which at least one of the second product 14, the second gas 20, and the base 200a, the surface of which has been partially etched, reacts with each other, and a second modified layer 200d is formed on the surface of the base 200a, the surface of which has been partially etched. FIG. 5(h) is a partial enlarged cross-sectional view of the wafer 200 in a state in which the first gas 10 is supplied to the wafer 200 in which the second modified layer 200d is formed on the surface of the base 200a, the surface of which has been partially etched, and the first gas is adsorbed on the surface of the second modified layer 200d. Fig. 5(i) is a partial enlarged cross-sectional view of the wafer 200 in a state where the first gas 10 reacts with the second modified layer 200d and a product 30 is generated on the surface of the partially etched underlayer 200a. Fig. 5(j) is a partial enlarged cross-sectional view of the wafer 200 in a state where the product 30 generated on the surface of the partially etched underlayer 200a is desorbed from the surface of the underlayer 200a. Fig. 5(k) is a partial enlarged cross-sectional view of the wafer 200 in a state where the surface of the partially etched underlayer 200a is exposed again after the product 30 is desorbed from the surface of the partially etched underlayer 200a. [Figure 6] FIG. 6 is a diagram showing the measurement results of the etching rate in Reference Example 1. [Figure 7] FIG. 7 is a diagram showing the measurement results of the etching rate in Reference Example 2. In FIG. [Figure 8] FIG. 8 is a diagram showing the measurement results of the etching rate in the examples. [Figure 9] Fig. 9(a) is a partially enlarged cross-sectional view of the wafer 200 in a state before etching is performed on the wafer 200 with the underlayer 200a and underlayer 200e exposed on the surface. Fig. 9(b) is a partially enlarged cross-sectional view of the wafer 200 in a state during etching when etching is performed on the wafer 200 with the underlayer 200a and underlayer 200e exposed on the surface. Fig. 9(c) is a partially enlarged cross-sectional view of the wafer 200 in a state after etching is performed on the wafer 200 with the underlayer 200a and underlayer 200e exposed on the surface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <One aspect of the present disclosure> Hereinafter, one embodiment of the present disclosure will be described mainly with reference to Figures 1 to 4 and Figures 5(a) to 5(k). Note that all of the drawings used in the following description are schematic, and the dimensional relationships and ratios of each element on the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships and ratios of each element between multiple drawings do not necessarily match.

[0011] (1) Configuration of the substrate processing device 1, the process furnace 202 has a heater 207 as a heating mechanism (temperature regulator, temperature adjustment section). The heater 207 has a cylindrical shape and is installed vertically by being supported by a holding plate. The heater 207 also functions as an activation mechanism (excitation section) that activates (excites) gas by heat.

[0012] A reaction tube 203 is disposed inside the heater 207 concentrically with the heater 207. The reaction tube 203 is made of, for example, quartz (SiO 2 The reaction tube 203 is made of a heat-resistant material such as SUS or silicon carbide (SiC) and is formed in a cylindrical shape with the upper end closed and the lower end open. A manifold 209 is disposed concentrically with the reaction tube 203 below the reaction tube 203. The manifold 209 is made of a metal material such as stainless steel (SUS) and is formed in a cylindrical shape with the upper and lower ends open. The upper end of the manifold 209 engages with the lower end of the reaction tube 203 and is configured to support the reaction tube 203. An O-ring 220a is provided as a seal member between the manifold 209 and the reaction tube 203. The reaction tube 203 is installed vertically like the heater 207. The reaction tube 203 and the manifold 209 mainly constitute a processing vessel (reaction vessel). A processing chamber 201 is formed in the cylindrical hollow part of the processing vessel. The processing chamber 201 is configured to be able to accommodate a wafer 200 as a substrate. In the processing chamber 201, processing of the wafer 200 is performed.

[0013] Nozzles 249a to 249c serving as first to third supply units are provided in the processing chamber 201 so as to penetrate the sidewall of the manifold 209, respectively. The nozzles 249a to 249c are also referred to as first to third nozzles, respectively. The nozzles 249a to 249c are made of a heat-resistant material such as quartz or SiC. Gas supply pipes 232a to 232c are connected to the nozzles 249a to 249c, respectively. The nozzles 249a to 249c are different nozzles, and each of the nozzles 249a and 249c is provided adjacent to the nozzle 249b.

[0014] Gas supply pipes 232a-232c are provided with mass flow controllers (MFCs) 241a-241c, which are flow rate controllers (flow rate control parts), and valves 243a-243c, which are on-off valves, in order from the upstream side of the gas flow. Gas supply pipes 232d-232f are connected to the gas supply pipes 232a-232c downstream of the valves 243a-243c. Gas supply pipes 232d-232f are provided with MFCs 241d-241f and valves 243d-243f, which are provided from the upstream side of the gas flow. Gas supply pipes 232a-232f are made of a metal material, such as SUS.

[0015] As shown in FIG. 2, the nozzles 249a to 249c are provided in a circular space between the inner wall of the reaction tube 203 and the wafers 200 in a plan view, from the lower part to the upper part of the inner wall of the reaction tube 203, so as to rise upward in the arrangement direction of the wafers 200. That is, the nozzles 249a to 249c are provided in a region horizontally surrounding the wafer arrangement region on the side of the wafer arrangement region in which the wafers 200 are arranged, so as to extend along the wafer arrangement region. In a plan view, the nozzle 249b is disposed so as to face an exhaust port 231a (described later) on a straight line across the center of the wafer 200 loaded into the processing chamber 201. The nozzles 249a and 249c are disposed so as to sandwich a straight line L passing through the nozzle 249b and the center of the exhaust port 231a from both sides along the inner wall of the reaction tube 203 (the outer periphery of the wafer 200). The straight line L is also a straight line passing through the nozzle 249b and the center of the wafer 200. In other words, the nozzle 249c is provided on the opposite side of the nozzle 249a across the line L. The nozzles 249a and 249c are arranged symmetrically with respect to the line L. Gas supply holes 250a to 250c for supplying gas are provided on the side surfaces of the nozzles 249a to 249c, respectively. The gas supply holes 250a to 250c are each opened to face (face) the exhaust port 231a in a plan view, and are capable of supplying gas toward the wafer 200. A plurality of gas supply holes 250a to 250c are provided from the lower part to the upper part of the reaction tube 203.

[0016] A first gas is supplied from the gas supply pipe 232a through the MFC 241a, the valve 243a, and the nozzle 249a into the processing chamber 201. The first gas acts as a modifying agent or modifying gas.

[0017] A second gas is supplied from the gas supply pipe 232b through the MFC 241b, the valve 243b, and the nozzle 249b into the processing chamber 201. The second gas has a molecular structure different from that of the first gas. The second gas acts as an activation gas and a reaction gas.

[0018] A third gas is supplied from the gas supply pipe 232c through the MFC 241c, the valve 243c, and the nozzle 249c into the processing chamber 201. The third gas acts as a pre-processing gas.

[0019] From the gas supply pipes 232d to 232f, the inert gas is supplied via the MFCs 241d to 241f, the valves 243d to 243f, the gas supply pipes 232a to 232c, and the nozzles 249a to 249c, respectively, into the processing chamber 201. The inert gas acts as a purge gas, a carrier gas, a dilution gas, or the like.

[0020] A first gas supply system (modifying agent supply system, modifying gas supply system) is mainly composed of the gas supply pipe 232a, the MFC 241a, and the valve 243a. A second gas supply system (activated gas supply system, reactive gas supply system) is mainly composed of the gas supply pipe 232b, the MFC 241b, and the valve 243b. A third gas supply system (pretreatment gas supply system) is mainly composed of the gas supply pipe 232c, the MFC 241c, and the valve 243c. An inert gas supply system is mainly composed of the gas supply pipes 232d to 232f, the MFCs 241d to 241f, and the valves 243d to 243f.

[0021] Any or all of the various gas supply systems described above may be configured as an integrated gas supply system 248 in which the valves 243a-243f, MFCs 241a-241f, etc. are integrated. The integrated gas supply system 248 is connected to the gas supply pipes 232a-232f, respectively, and is configured so that the supply operation of various gases into the gas supply pipes 232a-232f, i.e., the opening and closing operation of the valves 243a-243f and the flow rate adjustment operation by the MFCs 241a-241f, etc., are controlled by a controller 121, which will be described later. The integrated gas supply system 248 is configured as an integrated or separate type integrated unit, and can be attached and detached to and from the gas supply pipes 232a-232f, etc., in units of integrated units, and is configured so that maintenance, replacement, expansion, etc. of the integrated gas supply system 248 can be performed in units of integrated units.

[0022] An exhaust port 231a for exhausting the atmosphere in the processing chamber 201 is provided at the lower side of the sidewall of the reaction tube 203. As shown in Fig. 2, the exhaust port 231a is provided at a position facing the nozzles 249a to 249c (gas supply holes 250a to 250c) across the wafer 200 in a plan view. The exhaust port 231a may be provided along the sidewall of the reaction tube 203 from the lower part to the upper part, i.e., along the wafer arrangement area. An exhaust pipe 231 is connected to the exhaust port 231a.

[0023] A vacuum pump 246 as a vacuum exhaust device is connected to the exhaust pipe 231 via a pressure sensor 245 as a pressure detector (pressure detection unit) that detects the pressure in the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 as a pressure regulator (pressure adjustment unit). The APC valve 244 can evacuate and stop the evacuation of the processing chamber 201 by opening and closing the valve while the vacuum pump 246 is in operation, and further, can adjust the pressure in the processing chamber 201 by adjusting the valve opening based on pressure information detected by the pressure sensor 245 while the vacuum pump 246 is in operation. An exhaust system is mainly configured by the exhaust pipe 231, the APC valve 244, and the pressure sensor 245. The vacuum pump 246 may be included in the exhaust system.

[0024] A seal cap 219 is provided below the manifold 209 as a furnace port cover capable of air-tightly closing the lower end opening of the manifold 209. The seal cap 219 is made of a metal material such as SUS and is formed in a disk shape. An O-ring 220b is provided on the upper surface of the seal cap 219 as a seal member that comes into contact with the lower end of the manifold 209.

[0025] A rotation mechanism 267 for rotating the boat 217, which will be described later, is installed below the seal cap 219. A rotation shaft 255 of the rotation mechanism 267 is connected to the boat 217 through the seal cap 219. The rotation mechanism 267 is configured to rotate the wafer 200 by rotating the boat 217. The seal cap 219 is configured to be raised and lowered in the vertical direction by a boat elevator 115 as a lifting mechanism installed outside the reaction tube 203. The boat elevator 115 is configured as a transfer device (transfer mechanism) for loading and unloading (transporting) the wafer 200 into and out of the processing chamber 201 by lifting and lowering the seal cap 219.

[0026] A shutter 219s is provided below the manifold 209 as a furnace port cover that can airtightly close the lower end opening of the manifold 209 when the seal cap 219 is lowered and the boat 217 is carried out of the processing chamber 201. The shutter 219s is made of a metal material such as SUS and is formed in a disk shape. An O-ring 220c is provided on the upper surface of the shutter 219s as a seal member that comes into contact with the lower end of the manifold 209. The opening and closing operation (lifting and lowering operation, rotating operation, etc.) of the shutter 219s is controlled by a shutter opening and closing mechanism 115s.

[0027] The boat 217 as a substrate support is configured to support a plurality of wafers 200, for example 25 to 200, in multiple stages in a horizontal position and aligned vertically with their centers aligned, i.e., arranged at intervals. The boat 217 is made of a heat-resistant material such as quartz or SiC. At the bottom of the boat 217, heat insulating plates 218 made of a heat-resistant material such as quartz or SiC are supported in multiple stages.

[0028] A temperature sensor 263 serving as a temperature detector is installed in the reaction tube 203. By adjusting the power supply to the heater 207 based on temperature information detected by the temperature sensor 263, the temperature distribution in the process chamber 201 becomes a desired one. The temperature sensor 263 is installed along the inner wall of the reaction tube 203.

[0029] 3, the controller 121, which is a control unit (control means), is configured as a computer including a CPU (Central Processing Unit) 121a, a RAM (Random Access Memory) 121b, a storage device 121c, and an I / O port 121d. The RAM 121b, the storage device 121c, and the I / O port 121d are configured to be able to exchange data with the CPU 121a via an internal bus 121e. An input / output device 122 configured as, for example, a touch panel, is connected to the controller 121.

[0030] The storage device 121c is composed of, for example, a flash memory, a hard disk drive (HDD), a solid state drive (SSD), etc. A control program for controlling the operation of the substrate processing apparatus, a process recipe in which procedures and conditions of the substrate processing described later are described, etc. are readably stored in the storage device 121c. The process recipe is a combination of procedures in the substrate processing described later that are executed by the controller 121 to obtain a predetermined result, and functions as a program. Hereinafter, the process recipe, the control program, etc. are collectively referred to simply as a program. In addition, the process recipe is also simply referred to as a recipe. In this specification, when the word program is used, it may include only a recipe, only a control program, or both. The RAM 121b is configured as a memory area (work area) in which the programs, data, etc. read by the CPU 121a are temporarily stored.

[0031] The I / O port 121d is connected to the above-mentioned MFCs 241a to 241f, valves 243a to 243f, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotation mechanism 267, boat elevator 115, shutter opening / closing mechanism 115s, and the like.

[0032] The CPU 121a is configured to read and execute a control program from the storage device 121c, and to read a recipe from the storage device 121c in response to an input of an operation command from the input / output device 122, etc. The CPU 121a is configured to control the flow rate adjustment operation of various gases by the MFCs 241a to 241f, the opening and closing operations of the valves 243a to 243f, the opening and closing operation of the APC valve 244 and the pressure adjustment operation by the APC valve 244 based on the pressure sensor 245, the start and stop of the vacuum pump 246, the temperature adjustment operation of the heater 207 based on the temperature sensor 263, the rotation and rotation speed adjustment operation of the boat 217 by the rotation mechanism 267, the lifting and lowering operation of the boat 217 by the boat elevator 115, the opening and closing operation of the shutter 219s by the shutter opening and closing mechanism 115s, etc., in accordance with the contents of the read recipe.

[0033] The controller 121 can be configured by installing the above-mentioned program stored in the external storage device 123 in a computer. The external storage device 123 includes, for example, a magnetic disk such as an HDD, an optical disk such as a CD, a magneto-optical disk such as an MO, a USB memory, a semiconductor memory such as an SSD, and the like. The storage device 121c and the external storage device 123 are configured as computer-readable recording media. Hereinafter, these are collectively referred to simply as recording media. When the term recording media is used in this specification, it may include only the storage device 121c alone, only the external storage device 123 alone, or both of them. The program may be provided to the computer using a communication means such as the Internet or a dedicated line, without using the external storage device 123.

[0034] (2) Substrate processing An example of an etching process sequence for etching the base 200a as a first film exposed on the surface of the wafer 200 as a substrate as one step of a manufacturing process of a semiconductor device using the above-mentioned substrate processing apparatus, i.e., an example of a gas supply sequence in the etching process, will be described mainly with reference to Figure 4 and Figures 5(a) to 5(k). In the following description, the operation of each part constituting the substrate processing apparatus is controlled by a controller 121.

[0035] In the gas supply sequence shown in FIG. A step A of supplying a first gas to the wafer 200 to form a first modified layer 200b on at least a part of a base 200a, which is a first film exposed on the surface of the wafer 200; a step B of generating etching species by at least one of supplying a second gas having a molecular structure different from that of the first gas to the wafer 200, reacting the second gas with the first modified layer 200b, and activating the first modified layer 200b with the second gas, and etching at least a part of the base 200a with the etching species; The above steps are non-simultaneously performed a predetermined number of times (n times, n is an integer equal to or greater than 1), thereby etching the base layer 200a.

[0036] In the gas supply sequence shown in FIG. 4, each step (ie, step A and step B) is performed in a non-plasma atmosphere.

[0037] In this specification, the above-mentioned processing sequence may be expressed as follows for convenience: Similar notations will be used in the following explanations of modified examples, etc.

[0038] (1st gas → 2nd gas) × n

[0039] In this specification, the term "wafer" may refer to the wafer itself or a laminate of the wafer and a layer or film formed on its surface. In this specification, the term "surface of a wafer" may refer to the surface of the wafer itself or the surface of a layer or the like formed on the wafer. In this specification, the term "forming a layer on a wafer" may refer to forming a layer directly on the surface of the wafer itself or forming a layer on a layer or the like formed on the wafer. In this specification, the term "substrate" is synonymous with the term "wafer".

[0040] In addition, when the term "base" is used in this specification, it may mean the wafer itself or a layer or film formed on the surface of the wafer. When the term "surface of the base" is used in this specification, it may mean the surface of the wafer itself or the surface of a layer or the like formed on the surface of the wafer. When the term "forming a layer on the surface of the base" is used in this specification, it may mean forming a layer directly on the surface of the wafer itself or forming a layer on the surface of a layer or the like formed on the surface of the wafer.

[0041] (Wafer charge and boat load) When a plurality of wafers 200 are loaded into the boat 217 (wafer charge), the shutter 219s is moved by the shutter opening / closing mechanism 115s to open the lower end opening of the manifold 209 (shutter open). Thereafter, as shown in FIG. 1, the boat 217 supporting the plurality of wafers 200 is lifted by the boat elevator 115 and carried into the processing chamber 201 (boat load). In this state, the seal cap 219 seals the lower end of the manifold 209 via the O-ring 220b. Note that the surface of the wafer 200 is exposed to the underlayer 200a as the first film to be etched. The underlayer 200a includes, for example, a silicon-based nitrogen-containing film such as a silicon nitride film (SiN film).

[0042] (Pressure and temperature regulation) The processing chamber 201, i.e., the space in which the wafer 200 is present, is evacuated (reduced pressure exhaust) by the vacuum pump 246 so that the pressure inside the processing chamber 201 is a desired pressure (vacuum level). At this time, the pressure inside the processing chamber 201 is measured by the pressure sensor 245, and the APC valve 244 is feedback-controlled based on the measured pressure information. Also, the wafer 200 inside the processing chamber 201 is heated by the heater 207 so that the processing temperature is a desired processing temperature. At this time, the power supply to the heater 207 is feedback-controlled based on the temperature information detected by the temperature sensor 263 so that the processing chamber 201 has a desired temperature distribution. Also, the rotation mechanism 267 starts rotating the wafer 200. The evacuation inside the processing chamber 201 and the heating and rotation of the wafer 200 are all continued at least until the processing of the wafer 200 is completed.

[0043] (Etching process) Thereafter, a cycle of performing the next step A and step B non-simultaneously is executed a predetermined number of times.

[0044] [Step A] In step A, a first gas is supplied to the wafer 200 in the processing chamber 201, that is, to the wafer 200 having the base 200a exposed on the surface as a first film.

[0045] Specifically, the valve 243a is opened to allow a first gas to flow into the gas supply pipe 232a. The flow rate of the first gas is adjusted by the MFC 241a, and the first gas is supplied into the processing chamber 201 via the nozzle 249a, flows over the surface of the wafer 200, and is exhausted from the exhaust port 231a. At this time, the first gas is supplied to the wafer 200. Also, at this time, the valves 243d to 243f may be opened to supply an inert gas into the processing chamber 201 via each of the nozzles 249a to 249c.

[0046] By supplying the first gas to the wafer 200 under the conditions described below, it becomes possible to uniformly modify the surface of the base 200a. Specifically, as shown in Fig. 5(a), when the first gas 10 is supplied to the wafer 200 having the base 200a exposed on its surface, the first gas 10 is uniformly adsorbed onto the surface of the base 200a to form a first modified layer 200b.

[0047] The first modified layer 200b is formed by at least one of physically or chemically adsorbing at least a part of the molecules of the first gas 10 to at least a part of the surface of the base 200a (hereinafter also referred to as modification by adsorption) and generating a compound by a chemical reaction between at least a part of the molecules of the first gas 10 and at least a part of the atoms or molecules on the surface of the base 200a (hereinafter also referred to as modification by compound generation). That is, in this step, it is possible to modify the surface of the base 200a by modification by adsorption and / or modification by compound generation using the first gas 10. FIG. 5(a) shows, as an example, the first modified layer 200b formed by adsorbing at least a part of the molecules of the first gas 10 to at least a part of the surface of the base 200a.

[0048] In the modification by adsorption, the modified portion of the underlayer 200a (i.e., the portion where the first modified layer 200b is formed) becomes the base of the etching species to be generated in step B described later. Therefore, the amount of the etching species to be generated in step B can be controlled by the amount of the first gas adsorbed on the surface of the underlayer 200a. Similarly, in the modification by compound generation, the modified portion of the underlayer 200a (i.e., the portion where the first modified layer 200b is formed) becomes the base of the etching species to be generated in step B described later. Therefore, the amount of the etching species to be generated in step B can be controlled by the amount of the compound to be generated on the surface of the underlayer 200a. Then, under the conditions described later, the first modified layer 200b can be formed uniformly in the surface of the underlayer 200a, and thus, in step B described later, the etching species can be generated uniformly in the surface of the underlayer 200a.

[0049] Depending on the processing conditions, a self-limit can be generated in the reaction forming the first modified layer 200b. That is, depending on the processing conditions, the modification reaction by adsorption can be saturated, and the modification reaction by compound generation can be saturated. By saturating the reaction forming the first modified layer 200b, it becomes possible to form the first modified layer 200b more uniformly in the surface of the base 200a. This makes it possible to generate etching species more uniformly in the surface of the base 200a in step B described later.

[0050] After the formation of the first modified layer 200b on the surface of the base 200a is completed, the valve 243a is closed to stop the supply of the first gas into the processing chamber 201. Then, the processing chamber 201 is evacuated to remove gas remaining in the processing chamber 201 from the processing chamber 201. At this time, the valves 243d to 243f may be opened to supply an inert gas into the processing chamber 201 through the nozzles 249a to 249c. The inert gas supplied from the nozzles 249a to 249c acts as a purge gas, thereby purging the processing chamber 201 (purging). Purging with the inert gas may not be performed. The above-mentioned purge removes the first gas 10 and the like that is not adsorbed to the wafer 200, leaving the first modified layer 200b on the surface of the base 200a.

[0051] In step A, the process conditions for supplying the first gas are as follows: Treatment temperature: 25 to 400°C, preferably 50 to 250°C Treatment pressure: 1 to 13,300 Pa, preferably 50 to 2,660 Pa First gas supply flow rate: 1 to 5000 sccm, preferably 50 to 2000 sccm First gas supply time: 1 to 3000 sec, preferably 10 to 1200 sec Inert gas supply flow rate (per gas supply pipe): 100 to 5000 sccm, preferably 100 to 3000 sccm Examples are given below.

[0052] Here, in this specification, when a numerical range such as "25 to 400°C" is expressed, it means that the lower limit and the upper limit are included in the range. Thus, for example, "25 to 400°C" means "25°C or higher and 400°C or lower". The same applies to other numerical ranges. Note that the process temperature means the temperature of the wafer 200, and the process pressure means the pressure inside the process chamber 201. The same applies in the following explanation.

[0053] Under the above processing conditions, the first modified layer 200b can be formed at a practical formation rate by setting the processing temperature to 25° C. or higher, preferably 50° C. or higher. Moreover, under the above processing conditions, the processing temperature to 400° C. or lower, preferably 250° C. or lower, can prevent the first film (underlying layer 200a) from being directly etched by the first gas, and can uniformly form the first modified layer 200b in the surface of the underlayer 200a.

[0054] In this step, the first gas can be supplied to the wafer 200 under conditions that allow the reaction forming the first modified layer 200b to be saturated. This allows the first modified layer 200b to be formed more uniformly within the surface of the base 200a. For example, the reaction forming the first modified layer 200b can be saturated by setting the processing temperature to a predetermined temperature of 250° C. or less, preferably 200° C. or less, and more preferably 150° C. or less. Even when such a processing temperature is used, the reaction forming the first modified layer 200b can be unsaturated by adjusting conditions other than the processing temperature (for example, shortening the first gas supply time, lowering the processing pressure, etc.).

[0055] The above process conditions can also be said to be conditions under which the etching reaction of the underlayer 200a does not proceed continuously when the first gas is present alone (i.e., when the first gas is supplied alone to the wafer 200 with the underlayer 200a exposed, the same applies below). The above process conditions are also conditions under which the etching reaction of the underlayer 200a does not proceed continuously when the second gas is present alone (i.e., when the second gas is supplied alone to the wafer 200 with the underlayer 200a exposed, the same applies below).

[0056] The processing conditions for purging with an inert gas in step A are as follows: Treatment temperature: 25 to 400°C, preferably 50 to 250°C Treatment pressure: 1 to 13300 Pa, preferably 50 to 1330 Pa Inert gas supply flow rate (per gas supply pipe): 100 to 5000 sccm, preferably 500 to 3000 sccm Inert gas supply time: 1 to 600 seconds, preferably 10 to 120 seconds Examples are given below.

[0057] The first gas used in step A is not particularly limited as long as it is a gas capable of modifying the surface of the base 200a, which is the first film.

[0058] Examples of the first gas include a silicon (Si)-containing gas, a metal-containing gas, an oxygen (O)-containing gas, a nitrogen (N)- and hydrogen (H)-containing gas, a boron (B)-containing gas, a phosphorus (P)-containing gas, a halogen-containing gas, and the like, and one or more of these can be used.

[0059] As the Si-containing gas given as an example of the first gas, for example, an aminosilane-based gas that contains Si and an amino group can be used.

[0060] Here, the amino group is a functional group (NH 2(functional group in which one or both of H of an amino group represented by the formula (I) are substituted with a hydrocarbon group containing one or more C atoms). When two hydrocarbon groups constituting a part of an amino group are coordinated to one N, the two may be the same hydrocarbon group or different hydrocarbon groups. The hydrocarbon group may contain a single bond like an alkyl group, or may contain an unsaturated bond such as a double bond or a triple bond. The amino group may have a cyclic structure. Since the amino group is bonded to Si, which is the central atom of the aminosilane molecule, the amino group in the aminosilane may also be referred to as a ligand (ligand) or an amino ligand. The aminosilane-based gas may contain Si and an amino group, and may further contain a hydrocarbon group. The hydrocarbon group may contain a single bond like an alkyl group, or may contain an unsaturated bond such as a double bond or a triple bond. The hydrocarbon group may have a cyclic structure. The hydrocarbon group may be bonded to Si, which is the central atom of the aminosilane molecule, and in that case, the hydrocarbon group in the aminosilane may also be referred to as a ligand or a hydrocarbon ligand. When the hydrocarbon group is an alkyl group, the hydrocarbon group may be referred to as an alkyl ligand. Hereinafter, the alkyl group may be represented by R.

[0061] As an example of an aminosilane gas, dimethylaminotrimethylsilane ((CH 3 ) 2 NSi(CH 3 ) 3 , abbreviation: DMATMS) gas, diethylaminotrimethylsilane ((C 2 H 5 ) 2 NSi(CH 3 ) 3 , abbreviation: DEATMS) gas, diethylaminotriethylsilane ((C 2 H 5 ) 2 NSi(C 2 H 5 ) 3 , abbreviation: DEATES) gas, dimethylaminotriethylsilane ((CH 3 ) 2 NSi(C 2 H 5) 3 , abbreviated as DMATMS) gas, etc. can be used. The central atom of DMATMS, DEATMS, DEATES, DMATES, etc., is Si, to which one amino group (dimethylamino group or diethylamino group) is bonded, as well as three alkyl groups (methyl group or ethyl group). In other words, DMATMS, DEATMS, DEATES, DMATES, etc., contain one amino ligand and three alkyl ligands.

[0062] In addition to the above, the aminosilane-based gas may also be a gas of an aminosilane compound represented by the following formula [1]:

[0063] SiA x [(NB 2 ) (4-x) ][1]

[0064] In the formula [1], A represents an H atom, an alkyl group, or an alkoxy group, B represents an H atom or an alkyl group, and x represents an integer of 1 to 3. The alkyl group represented by A is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms. The alkyl group represented by A may be linear or branched. Examples of the alkyl group represented by A include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isopropyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. The alkoxy group represented by A is preferably an alkoxy group having 1 to 5 carbon atoms, and more preferably an alkoxy group having 1 to 4 carbon atoms. The alkyl group in the alkoxy group represented by A is the same as the alkyl group represented by A above. When x is 2 or 3, two or three A may be the same or different. The alkyl group represented by B is the same as the alkyl group represented by A above. In addition, two B may be the same or different, and when x is 1 or 2, a plurality of (NB 2 ) may be the same or different. Furthermore, two B's may be bonded to form a ring structure, and the ring structure formed may further have a substituent such as an alkyl group.

[0065] The aminosilane gas represented by formula [1] may be, for example, monoaminosilane (SiH 3 (NR 2 ), abbreviated as MAS gas, and bisaminosilane (SiH 2 (NR 2 ) 2 (abbreviation: BAS) gas, and trisaminosilane (SiH(NR 2 ) 3 (abbreviated as TAS) gas can be used. Among them, it is preferable to use MAS gas as the aminosilane-based gas. By using MAS gas as the first gas, it is possible to modify the surface of the base 200a more uniformly and sufficiently in step A.

[0066] The MAS gas may be, for example, ethylmethylaminosilane (SiH 3 [N(CH 3 )(C 2 H 5 )]) gas, dimethylaminosilane (SiH 3 [N(CH 3 ) 2 ]) gas, diisopropylaminosilane (SiH 3 [N(C 3 H 7 ) 2 ]) gas, di-secondary butyl amino silane (SiH 3 [H(C 4 H 9 ) 2 ]) gas, dimethylpiperidinosilane (SiH 3 [NC 5 H 8 (CH 3 ) 2 ]) gas, diethylpiperidinosilane (SiH3 [NC 5 H 8 (C 2 H 5 ) 2 In this specification, the MAS gas may be any gas containing an aminosilane compound having one amino group in one molecule, and the above-mentioned SiH 3 (NR 2 ) is also included. For example, the above-mentioned DMATMS, DEATMS, DEATES, and DMATES are also aminosilane compounds that contain one amino group per molecule, and therefore can also be included in the MAS gas. Note that the above-mentioned DMATMS, DEATMS, DEATES, and DMATES are aminosilane compounds in which A in formula [1] is an alkyl group, B is an alkyl group, and x is 3.

[0067] As the Si-containing gas given as an example of the first gas, for example, a halosilane-based gas, which is a gas containing Si and a halogeno group, can be used. The halogeno group preferably contains at least one of a fluoro group, a chloro group, a bromo group, and an iodine group, and more preferably contains a chloro group. That is, the halosilane-based gas preferably contains at least one of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), and more preferably contains Cl. As the halosilane-based gas, for example, hexachlorodisilane (Si 2 Cl 6 ) gas, tetrachlorosilane (SiCl 4 ) gas, trichlorosilane (SiHCl 3 ) gas, dichlorosilane (SiH 2 Cl 2 ) gas, monochlorosilane (SiH 3 Chlorosilane gases such as chlorosilane (Cl) gas, tetrafluorosilane (SiF 4 ) gas, difluorosilane (SiH 2 F 2 ) gas, tetrabromosilane (SiBr 4 ) gas, dibromosilane (SiH2 Br 2 ) gas, tetraiodosilane (SiI 4 ) gas, diiodosilane (SiH 2 I 2 ) gas and other iodosilane-based gases, and one or more of these can be used.

[0068] Moreover, an alkylhalosilane gas may be used as the halosilane gas. For example, dimethyldichlorosilane ((CH 3 ) 2 SiCl 2 ) gas, trimethylchlorosilane ((CH 3 ) 3 SiCl) gas and other alkylchlorosilane gases, dimethyldifluorosilane ((CH 3 ) 2 SiF 2 ) gas, trimethylfluorosilane ((CH 3 ) 3 SiF) gas and other alkylfluorosilane gases, dimethyldibromosilane ((CH 3 ) 2 SiBr 2 ) gas, trimethylbromosilane ((CH 3 ) 3 SiBr) gas and other alkylbromosilane gases, dimethyldiiodosilane ((CH 3 ) 2 SiI 2 ) gas, trimethyliodosilane ((CH 3 ) 3 and alkyl iodosilane gases such as SiI) gas. One or more of these can be used.

[0069] As an example of the first gas, a gas containing Si and H, that is, a silicon hydride gas, can be used. As the silicon hydride gas, for example, monosilane (SiH 4 ) gas, disilane (Si 2 H 6 ) gas, trisilane (Si 3 H8 ) gas, tetrasilane (Si 4 H 10 ) gases, etc., and one or more of these can be used.

[0070] Examples of the metal-containing gas given as an example of the first gas include a gas containing a metal and an amino group, a gas containing a metal and a halogeno group, and the like. The halogeno group preferably contains at least one of a fluoro group, a chloro group, a bromo group, and an iodine group, and more preferably contains a chloro group. That is, the gas containing a metal and a halogeno group preferably contains at least one of F, Cl, Br, and I, and more preferably contains Cl. Examples of these gases include tetrakis(dimethylamino)titanium (Ti[N(CH 3 ) 2 ] 4 ) gas, tetrakis(diethylamino)titanium (Ti[N(C 2 H 5 ) 2 ] 4 ) gas, titanium tetrafluoride (TiF 4 ) gas, titanium tetrachloride (TiCl 4 ) gas, titanium tetrabromo (TiBr 4 ) gas, titanium tetraiodide (TiI 4 ) gases, etc., and one or more of these can be used.

[0071] An example of the first gas that contains O is, for example, oxygen (O 2 ) gas, nitric oxide (NO) gas, nitrogen dioxide (NO 2 ) gas, nitrous oxide (N 2 O) gas, ozone (O 3 ) gas, water vapor (H 2 O gas), hydrogen peroxide (H 2 O 2 ) Gas, O 2 Gas + H 2 Gas, O 3 Gas + H 2 gas, etc., and one or more of these can be used.

[0072] Examples of the first gas that contains N and H include ammonia (NH 3 ) gas, hydrazine (N 2 H 4 ) gas, diazene (N 2 H 2 ) gas, monomethylhydrazine (CH 3 HN 2 H 2 ) gas, dimethylhydrazine ((CH 3 ) 2 N 2 (CH 3 )H) gas, trimethylhydrazine ((CH 3 ) 3 N 2 H 2 ) gases, etc., and one or more of these can be used.

[0073] Examples of the first gas that can be used include a B-containing gas and a P-containing gas, such as a B and H-containing gas and a P and H-containing gas. 2 H 6 ) gas, phosphine (PH 3 ) gases, etc., and one or more of these can be used.

[0074] Examples of halogen-containing gases that can be used as the first gas include C and F-containing gas, Cl and F-containing gas, F-containing gas, N and F-containing gas, N, F and O-containing gas, and N, Cl and O-containing gas. Examples of these gases include tetrafluoromethane (CF 4 ) gas, hexafluoroethane (C 2 F 6 ) gas, octafluoropropane (C 3 F 8 ) gas, chlorine monofluoride (ClF) gas, chlorine trifluoride (ClF 3 ) gas, fluorine (F 2 ) gas, nitrogen trifluoride (NF 3 ) gas, nitrosyl fluoride (FNO) gas, nitrosyl trifluoride (F3 NO) gas, nitrofluoride (FNO 2 ) gas, nitrosyl chloride (ClNO) gas, NF 3 Gas + NO gas, F 2 Gas + NO gas, ClF gas + NO gas, ClF 3 gas + NO gas, etc., and one or more of these can be used.

[0075] In this specification, "NF 3 The description of two gases, such as "NF gas + NO gas", is 3 In the case of supplying a mixed gas, the two gases may be mixed (premixed) in a supply pipe and then supplied into the processing chamber 201, or the two gases may be separately supplied into the processing chamber 201 through different supply pipes and then mixed (postmixed) in the processing chamber 201.

[0076] In addition, gases that are difficult to store, such as FNO gas, e.g. 2 It is preferable to generate FNO gas by mixing the FNO gas and NO gas in a supply pipe or nozzle installed in the substrate processing apparatus, and supply the FNO gas generated in the supply pipe or nozzle into the processing chamber 201. Also, for example, a gas mixing chamber is provided in the substrate processing apparatus, and FNO gas is mixed in the gas mixing chamber. 2 The FNO gas may be generated by mixing the gas with NO gas, and the FNO gas generated in the gas mixing chamber may be supplied into the processing chamber 201 through a supply pipe or a nozzle.

[0077] The inert gas used in step A is, for example, nitrogen (N 2 In addition to the above gas, rare gases such as argon (Ar) gas, helium (He) gas, neon (Ne) gas, xenon (Xe) gas, etc. can be used. As the inert gas, the same gas can be used in each step described later.

[0078] [Step B] In step B, after step A is completed, a second gas is supplied to the wafer 200 in the processing chamber 201, that is, to the wafer 200 having the first modified layer 200b formed on the surface of the base 200a. As described above, the second gas is a gas having a molecular structure different from that of the first gas.

[0079] Specifically, the valve 243b is opened to allow the second gas to flow into the gas supply pipe 232b. The flow rate of the second gas is adjusted by the MFC 241b, and the second gas is supplied into the processing chamber 201 via the nozzle 249b, flows over the surface of the wafer 200, and is exhausted from the exhaust port 231a. At this time, the second gas is supplied to the wafer 200. Also, at this time, the valves 243d to 243f may be opened to supply an inert gas into the processing chamber 201 via each of the nozzles 249a to 249c.

[0080] By supplying the second gas to the wafer 200 under conditions described below, etching species are generated from the first modified layer 200b formed on the surface of the base 200a. Specifically, when the second gas 20 is supplied to the wafer 200 having the first modified layer 200b formed on the surface of the base 200a as shown in Fig. 5(b), the first modified layer 200b (here, the first gas 10 adsorbed on the surface of the base 200a) is activated by the second gas 20, and etching species 200c are generated as shown in Fig. 5(c).

[0081] The etching species 200c are generated by at least one of reacting the second gas with the first modified layer 200b and activating the first modified layer 200b with the second gas. The former method of generating the etching species 200c is also referred to as etching species generation by reaction. The latter method of generating the etching species 200c is also referred to as etching species generation by activation. That is, in this step, the etching species 200c are generated on the surface of the base 200a by etching species generation by reaction and / or etching species generation by activation. The etching species 200c are generated based on the first modified layer 200b formed in a layered form and exist in a layered form, so the etching species 200c can also be referred to as a layer 200c containing etching species, an etching species-containing layer 200c, or simply an etching species layer 200c. FIG. 5(c) shows, as an example, etching species 200c generated by activating the first gas 10 adsorbed on the surface of the base 200a with the second gas 20, that is, a layer 200c containing the etching species.

[0082] When the etching species 200c are generated on the surface of the base 200a, a part of the surface of the base 200a is etched by the etching species 200c as shown in Fig. 5(d). When a part of the surface of the base 200a is etched by the etching species 200c, for example, a first product 12, which is a by-product, is generated in the process of the etching reaction as shown in Fig. 5(d). At this time, in addition to the first product 12, a second product 14 may also be generated as a by-product. Hereinafter, a case where the first product 12 and the second product 14 are generated as by-products will be described.

[0083] When a part of the surface of the base 200a is etched by the etching species 200c, the first product 12 and the second product 14, which are by-products, are generated. For example, as shown in FIG. 5(e), the first product 12 is desorbed from the surface of the base 200a. At this time, the second product 14 remains on the surface of the base 200a. At this time, a part of the second product 14 may be desorbed from the surface of the base 200a. At this time, the second product 14 may behave in such a way that it repeats desorption from the surface of the base 200a and adsorption to the surface of the base 200a. FIG. 5(e) shows, as an example, the desorption of the second product 14 from the surface of the base 200a and adsorption to the surface of the base 200a. After that, the second product 14 remains and / or is adsorbed uniformly in the surface of the base 200a whose surface has been partially etched, as shown in FIG. 5(f).

[0084] In this way, when the second product 14 remains and / or is adsorbed uniformly in the surface of the base 200a whose surface has been partially etched, at least one of the second product 14, the second gas 20, and the base 200a whose surface has been partially etched reacts with each other, as shown in FIG. 5(g), to form a second modified layer 200d on the surface of the base 200a whose surface has been partially etched. For example, the second modified layer 200d may be formed by the reaction of the second product 14 and the second gas 20 with the base 200a whose surface has been partially etched. Also, for example, the second modified layer 200d may be formed by the reaction of the second product 14, the second gas 20, and the base 200a whose surface has been partially etched.

[0085] When the base 200a is a silicon-based nitrogen-containing film such as a SiN film, and at least one of the first gas and the second gas is the above-mentioned halogen-containing gas, the first modified layer 200b may become an adsorption layer of the halogen-containing gas. In this case, the first product 12 may be a substance containing at least one of nitrogen, halogen, and silicon, and the second product 14 may be a substance containing at least one of nitrogen, oxygen, silicon, and halogen. In this case, the second modified layer 200d may be a substance containing silicon, oxygen, and halogen.

[0086] As described above, in this step, the second product 14 may not be generated as a by-product, in which case the second modified layer 200d will not be formed on the surface of the base 200a, the surface of which has been partially etched.

[0087] As described above, in this step, the etching species 200c are generated by the second gas using the first modified layer 200b as a base, and a part of the surface of the base 200a is etched by the generated etching species 200c. Through such a process, it is possible to improve the controllability of the etching amount when etching the base 200a.

[0088] This is because this technique does not directly etch the film to be etched (here, the base 200a) using an etching gas, and is therefore less susceptible to the distribution of gas partial pressure (≒ supply amount) resulting from the shape of the film to be etched.

[0089] In this method, the amount of etching of the underlayer 200a can be controlled by controlling the amount of etching species 200c generated in step B. The amount of etching species 200c can be controlled by the amount of the first gas adsorbed on the surface of the underlayer 200a in step A and the amount of compounds generated on the surface of the underlayer 200a in step A. That is, the amount of etching species 200c can be controlled by the amount of the first modified layer 200b formed in step A, i.e., the thickness of the first modified layer 200b, i.e., the amount of modification of the underlayer 200a in step A. In step A, the first modified layer 200b is uniformly formed in the surface of the underlayer 200a, so that in step B, etching species can be uniformly generated in the surface of the underlayer 200a, and the uniformity of the amount of etching of the underlayer 200a can be improved. This enables conformal etching processing.

[0090] As described above, in step A, a self-limit can be generated in the reaction forming the first modified layer 200b. That is, in step A, the modification reaction by adsorption can be saturated, and the modification reaction by compound generation can also be saturated. By saturating the reaction forming the first modified layer 200b, the first modified layer 200b can be formed more uniformly in the surface of the base 200a. As a result, in step B, etching species can be generated more uniformly in the surface of the base 200a, and the uniformity of the etching amount of the base 200a can be further improved. This further enables a conformal etching process. As a method for saturating the modification reaction, the method for saturating the modification reaction by adsorption can improve the controllability of the etching amount more than the method for saturating the modification reaction by compound generation.

[0091] As described above, the amount of the etching species 200c generated in step B depends on the amount of the first modified layer 200b formed in step A. That is, after the generation reaction of the etching species 200c based on the first modified layer 200b is completed in step B, the etching species 200c is not generated any more even if the second gas is further supplied. That is, after the entire first modified layer 200b is converted into the etching species in step B, or after the components that convert the first modified layer 200b into the etching species disappear, the etching species 200c is not generated any more even if the second gas is further supplied. In this way, in this method, not only the modification reaction in step A can be saturated, but also the generation reaction of the etching species 200c in step B can be saturated. It is also possible to make the modification reaction in step A and / or the generation reaction of the etching species 200c in step B unsaturated, which makes it possible to control the etching amount more precisely and finely.

[0092] After the etching of a part of the surface of the base 200a by the etching species 200c is completed and the second modified layer 200d is formed on the surface of the base 200a whose surface has been partially etched, the valve 243b is closed and the supply of the second gas 20 into the processing chamber 201 is stopped. Then, the processing chamber 201 is evacuated to a vacuum by the same processing procedure as the purging in step A, and gases remaining in the processing chamber 201 are removed from the processing chamber 201. At this time, similar to step A, the valves 243d to 243f may be opened and an inert gas may be supplied into the processing chamber 201 through the nozzles 249a to 249c to perform purging with the inert gas. The above purging removes the second gases remaining in the processing chamber 201 while leaving the second modified layer 200d on the surface of the base 200a whose surface has been partially etched.

[0093] The process conditions for supplying the second gas in step B are as follows: Treatment temperature: 25 to 400°C, preferably 50 to 250°C Treatment pressure: 1 to 13,300 Pa, preferably 50 to 2,660 Pa Second gas supply flow rate: 1 to 5000 sccm, preferably 50 to 2000 sccm Second gas supply time: 1 to 3000 sec, preferably 10 to 1200 sec Inert gas supply flow rate (per gas supply pipe): 100 to 5000 sccm, preferably 100 to 3000 sccm Examples are given below.

[0094] Under the above processing conditions, the processing temperature is set to 25° C. or higher, preferably 50° C. or higher, thereby enabling generation of etching species by reaction and / or generation of etching species by activation. Moreover, under the above processing conditions, the processing temperature is set to 400° C. or lower, preferably 250° C. or lower, thereby enabling promotion of etching of the first film (underlying layer 200a) by the etching species 200c while suppressing direct etching of the first film (underlying layer 200a) by the second gas 20.

[0095] The above process conditions can be said to be conditions under which the etching reaction of the underlayer 200a does not proceed continuously when the second gas is present alone. The above process conditions are also conditions under which the etching reaction of the underlayer 200a does not proceed continuously when the first gas is present alone.

[0096] In this step, the second gas is supplied to the wafer 200 under conditions in which the reaction between the second gas and the first modified layer 200b occurs more predominantly (is dominant) than the reaction between the second gas and the underlayer 200a. This makes it possible to promote the generation of etching species that contribute to the etching of the underlayer 200a while suppressing direct etching of the underlayer 200a with the second gas. As a result, it becomes possible to further improve the controllability of the etching amount when etching the underlayer 200a. In the above processing conditions, for example, by setting the processing temperature to a predetermined temperature of 400°C or less, preferably 250°C or less, it becomes possible to supply the second gas to the wafer 200 under conditions in which the reaction between the second gas and the first modified layer 200b occurs more predominantly than the reaction between the second gas and the underlayer 200a.

[0097] In addition, in this step, the second gas can be supplied to the wafer 200 under conditions where the reaction between the second gas and the first modified layer 200b proceeds and the reaction between the second gas and the underlayer 200a does not proceed. This makes it possible to promote the generation of etching species that contribute to the etching of the underlayer 200a while reliably suppressing the direct etching of the underlayer 200a by the second gas. As a result, it becomes possible to further improve the controllability of the etching amount when etching the underlayer 200a. In the above processing conditions, for example, by setting the processing temperature to a predetermined temperature of 250°C or less, preferably 200°C or less, more preferably 150°C or less, it becomes possible to supply the second gas to the wafer 200 under conditions where the reaction between the second gas and the first modified layer 200b proceeds and the reaction between the second gas and the underlayer 200a does not proceed.

[0098] In this step, the second gas is supplied to the wafer 200 under conditions where activation of the first modified layer 200b by the second gas occurs more predominantly than activation of the underlayer 200a by the second gas. This makes it possible to promote the generation of etching species that contribute to etching of the underlayer 200a while suppressing direct etching of the underlayer 200a by the second gas. As a result, it becomes possible to further improve the controllability of the etching amount when etching the underlayer 200a. In the above processing conditions, for example, by setting the processing temperature to a predetermined temperature of 400°C or less, preferably 250°C or less, it becomes possible to supply the second gas to the wafer 200 under conditions where activation of the first modified layer 200b by the second gas occurs more predominantly than activation of the underlayer 200a by the second gas.

[0099] In addition, in this step, the second gas can be supplied to the wafer 200 under conditions where the activation of the first modified layer 200b by the second gas proceeds and the activation of the underlayer 200a by the second gas does not proceed. This makes it possible to promote the generation of etching species that contribute to the etching of the underlayer 200a while reliably suppressing the direct etching of the underlayer 200a by the second gas. As a result, it becomes possible to further improve the controllability of the etching amount when etching the underlayer 200a. In the above processing conditions, for example, by setting the processing temperature to a predetermined temperature of 250°C or less, preferably 200°C or less, more preferably 150°C or less, it becomes possible to supply the second gas to the wafer 200 under conditions where the activation of the first modified layer 200b by the second gas proceeds and the activation of the underlayer 200a by the second gas does not proceed.

[0100] In addition, in this step, the second gas is supplied to the wafer 200 under conditions in which the etching of the underlayer 200a by the etching species proceeds more rapidly than the reaction between the second gas and the underlayer 200a. This makes it possible to suppress direct etching of the underlayer 200a by the second gas, and to allow the etching reaction of the underlayer 200a by the etching species to occur predominantly. As a result, it becomes possible to further improve the controllability of the etching amount when etching the underlayer 200a. In the above processing conditions, for example, by setting the processing temperature to a predetermined temperature of 400° C. or less, preferably 250° C. or less, it becomes possible to supply the second gas to the wafer 200 under conditions in which the etching of the underlayer 200a by the etching species proceeds more rapidly than the reaction between the second gas and the underlayer 200a.

[0101] In addition, the processing conditions in this step can also supply the second gas to the wafer 200 under conditions in which the etching of the underlayer 200a by the etching species proceeds and the reaction between the second gas and the underlayer 200a does not proceed. This reliably suppresses direct etching of the underlayer 200a by the second gas, and makes it possible to more predominantly cause the etching reaction of the underlayer 200a by the etching species. As a result, it becomes possible to further improve the controllability of the etching amount when etching the underlayer 200a. In the above processing conditions, for example, by setting the processing temperature to a predetermined temperature of 250° C. or less, preferably 200° C. or less, more preferably 150° C. or less, it becomes possible to supply the second gas to the wafer 200 under conditions in which the etching of the underlayer 200a by the etching species proceeds and the reaction between the second gas and the underlayer 200a does not proceed.

[0102] As described above, in this step, the second gas can be supplied to the wafer 200 under conditions that allow the generation reaction of the etching species 200c to be saturated. For example, the processing temperature can be set to a predetermined temperature of 400° C. or less, preferably 250° C. or less, to allow the generation reaction of the etching species 200c to be saturated. For example, even if the processing temperature is set to a predetermined temperature of 200° C. or less, 150° C. or less, the generation reaction of the etching species 200c can be saturated. As described above, in this step, after all of the first modified layer 200b is converted into etching species, or after the components that convert the first modified layer 200b into etching species disappear, the etching species 200c is no longer generated, so the generation reaction of the etching species 200c is relatively easily saturated. However, even if such a processing temperature is used, the generation reaction of the etching species 200c can be unsaturated by adjusting conditions other than the processing temperature (for example, shortening the second gas supply time, lowering the processing pressure, etc.).

[0103] The processing conditions for purging with an inert gas in step B are as follows: Treatment temperature: 25 to 400°C, preferably 50 to 250°C Treatment pressure: 1 to 13300 Pa, preferably 50 to 1330 Pa Inert gas supply flow rate (per gas supply pipe): 100 to 5000 sccm, preferably 500 to 3000 sccm Inert gas supply time: 1 to 600 seconds, preferably 10 to 120 seconds Examples are given below.

[0104] The second gas used in step B is not particularly limited as long as it is a gas that can react with the first modified layer 200b and / or activate the first modified layer 200b to generate etching species.

[0105] The second gas may be, for example, a halogen-containing gas, an acetylacetone-based gas, etc. Examples of the halogen-containing gas and the acetylacetone-based gas include an I and F-containing gas, a B and Cl-containing gas, a Cl-containing gas, an H and Cl-containing gas, an S, O and Cl-containing gas, an H and F-containing gas, a metal and F-containing gas, a metal and Cl-containing gas, a Cl and F-containing gas, an F-containing gas, an N and F-containing gas, an N, F and O-containing gas, an N, Cl and O-containing gas, a C, H and O-containing gas, a C, H, F and O-containing gas, etc.

[0106] These gases include, for example, iodine heptafluoride (IF 7 ) gas, iodine pentafluoride (IF 5 ) gas, boron trichloride (BCl 3 ) gas, chlorine (Cl 2 ) gas, hydrogen chloride (HCl) gas, thionyl chloride (SOCl 2 ) gas, hydrogen fluoride (HF) gas, tungsten hexafluoride (WF 6 ) gas, tungsten hexachloride (WCl 6 ) gas, tungsten pentachloride (WCl 5 ) gas, chlorine monofluoride (ClF) gas, chlorine trifluoride (ClF 3 ) gas, fluorine (F 2 ) gas, nitrogen trifluoride (NF 3 ) gas, nitrosyl fluoride (FNO) gas, nitrosyl trifluoride (F 3NO) gas, nitrofluoride (FNO 2 ) gas, nitrosyl chloride (ClNO) gas, acetylacetone (C 5 H 8 O 2 ) gas, hexafluoroacetylacetone (C 5 H 2 F 6 O 2 ) gases, etc., and one or more of these can be used.

[0107] As mentioned above, gases that are difficult to store, such as FNO gas, are 2 It is preferable to generate FNO gas by mixing the FNO gas and NO gas in a supply pipe or nozzle installed in the substrate processing apparatus, and supply the FNO gas generated in the supply pipe or nozzle into the processing chamber 201. Also, as described above, for example, a gas mixing chamber is provided in the substrate processing apparatus, and FNO gas is mixed in the gas mixing chamber. 2 The FNO gas may be generated by mixing the gas with NO gas, and the FNO gas generated in the gas mixing chamber may be supplied into the processing chamber 201 through a supply pipe or a nozzle.

[0108] [Step A from the second cycle onwards] As described above, in step B, the second modified layer 200d may be formed on the surface of the base 200a whose surface has been partially etched. In this case, in step A of the second cycle and thereafter, a first gas is supplied to the wafer 200 in the processing chamber 201, that is, to the wafer 200 on which the second modified layer 200d has been formed on the surface of the base 200a whose surface has been partially etched. The supply method and supply conditions of the first gas may be the same as those of step A described above.

[0109] Under the above-mentioned conditions, the first gas is supplied to the wafer 200 having the second modified layer 200d formed on the surface of the base 200a, the surface of which has been partially etched, so that the first gas 10 is adsorbed on the surface of the second modified layer 200d, as shown in FIG. 5(h). When the first gas 10 is adsorbed on the surface of the second modified layer 200d, the first gas 10 reacts with the second modified layer 200d, and the second modified layer 200d is removed, as shown in FIG. 5(i). In the process of the reaction between the first gas 10 and the second modified layer 200d, a by-product 30 is generated and is adsorbed on the surface of the base 200a after the second modified layer 200d has been removed. The product 30 may be, for example, the same substance as the first product 12.

[0110] Even after the product 30 is adsorbed on the surface of the underlayer 200a, the product 30 is desorbed from the surface of the underlayer 200a as shown in Fig. 5(j) by continuing to supply the first gas 10 to the wafer 200. Then, after the product 30 is desorbed from the surface of the underlayer 200a, the surface of the underlayer 200a is exposed again as shown in Fig. 5(k).

[0111] Then, even after the underlayer 200a is exposed again, the supply of the first gas 10 to the wafer 200 continues, so that the first gas 10 is adsorbed on the surface of the underlayer 200a to form a first modified layer 200b, as in the state shown in Fig. 5(a). The subsequent processing is performed in the same manner as in the first cycle, and the same reactions as in the first cycle occur.

[0112] In addition, if the second product 14 is not generated as a by-product in step B, the second modified layer 200d is not formed on the surface of the base 200a whose surface has been partially etched. In this case, the same reaction as in step A in the first cycle occurs in step A of the second cycle or later.

[0113] [Perform the specified number of times] By performing the above-mentioned steps A and B non-simultaneously, i.e., without synchronization, a predetermined number of times (n times, n being an integer equal to or greater than 1), it becomes possible to etch the underlayer 200a exposed on the surface of the wafer 200 to a desired depth. It is preferable to repeat the above-mentioned cycle multiple times. In other words, it is preferable to set the thickness of the layer etched in each cycle to be thinner than the desired thickness, and to repeat the above-mentioned cycle multiple times until the thickness of the layer removed by etching reaches the desired thickness.

[0114] (After purging and atmospheric pressure recovery) After the etching process of the base 200a is completed, an inert gas is supplied as a purge gas from each of the nozzles 249a to 249c into the processing chamber 201 and exhausted from the exhaust port 231a. This purges the processing chamber 201, and gas and reaction by-products remaining in the processing chamber 201 are removed from the processing chamber 201 (after-purge). Thereafter, the atmosphere in the processing chamber 201 is replaced with the inert gas (inert gas replacement), and the pressure in the processing chamber 201 is returned to normal pressure (return to atmospheric pressure).

[0115] (Boat unloading and wafer discharging) The seal cap 219 is lowered by the boat elevator 115, and the lower end of the manifold 209 is opened. Then, the processed wafers 200 are carried out from the lower end of the manifold 209 to the outside of the reaction tube 203 while being supported by the boat 217 (boat unloading). After the boat unloading, the shutter 219s is moved, and the lower end opening of the manifold 209 is sealed by the shutter 219s via the O-ring 220c (shutter close). After being carried out to the outside of the reaction tube 203, the processed wafers 200 are taken out of the boat 217 (wafer discharge).

[0116] (3) Effects of this mode According to this aspect, one or more of the following effects can be obtained.

[0117] By etching the underlayer 200a by performing a cycle of step A and step B non-simultaneously a predetermined number of times, the controllability of the etching amount of the underlayer 200a can be improved. That is, the underlayer 200a is not directly etched by the first gas or the second gas, but the etching species 200c generated on the surface of the underlayer 200a in step B is used to etch the underlayer 200a. This makes it possible to reduce the influence of the distribution of gas partial pressure (≒ supply amount) caused by the shape of the underlayer 200a, and to improve the controllability of the etching amount of the underlayer 200a. In this case, by controlling the amount of the etching species 200c generated on the surface of the underlayer 200a in step B, it becomes possible to freely control the etching amount of the underlayer 200a. For example, it becomes possible to control the etching amount of the underlayer 200a at a level of one atomic layer (one molecular layer) or less, and also at a level exceeding one atomic layer (one molecular layer), for example, at a level of several atomic layers (several molecular layers). The etching amount at a level of one atomic layer (one molecular layer) or less means that the etching thickness is at a level of one atomic layer (one molecular layer) or less than one atomic layer (one molecular layer). The etching amount at a level of less than one atomic layer (one molecular layer) means that the etching thickness is at a level less than one atomic layer (one molecular layer), and for example, the etching amount at half an atomic layer (half a molecular layer) corresponds to this level. Note that, according to this method, it is also possible to control the etching amount at a level of half an atomic layer (half a molecular layer), that is, at a level of half an atomic layer (half a molecular layer) or less than half an atomic layer (half a molecular layer).

[0118] For example, in a case where a 3D structure such as a trench or a hole is formed on the surface of the wafer 200 and the base 200a is provided along the surface shape, the amount of gas exposure is likely to decrease locally, or the partial pressure of the gas in the processing chamber 201 is not constant depending on the location, the base 200a is etched by performing a cycle of non-simultaneous steps A and B a predetermined number of times, so that the amount of etching of the base 200a can be precisely controlled to be uniform across the surface of the wafer 200. This enables conformal etching processing.

[0119] In order to achieve these effects, it is preferable to perform a cycle of non-simultaneously performing step A and step B a predetermined number of times under conditions in which the etching reaction of the underlayer 200a is unlikely to proceed continuously when at least one of the first gas and the second gas is present alone. It is more preferable to perform a cycle of non-simultaneously performing step A and step B a predetermined number of times under conditions in which the etching reaction of the underlayer 200a is unlikely to proceed continuously when each of the first gas and the second gas is present alone.

[0120] In step A, the portion where the first modified layer 200b is formed becomes the base for the etching species 200c to be generated on the surface of the base 200a in step B. Therefore, the amount of the etching species 200c to be generated in step B, i.e., the etching amount, can be controlled by the amount of the first gas adsorbed to the surface of the base 200a in step A.

[0121] For example, in step A, by setting the thickness of the adsorption layer of the first gas formed on the surface of the underlayer 200a (i.e., the first modified layer 200b, the same applies below) to one atomic layer (one molecular layer) or less, it is possible to control the etching amount (etching thickness) of the underlayer 200a in step B at a level of, for example, one atomic layer (one molecular layer) or less. Also, for example, in step A, by setting the thickness of the adsorption layer of the first gas formed on the surface of the underlayer 200a to less than one atomic layer (one molecular layer), it is possible to control the etching amount of the underlayer 200a in step B at a level of, for example, less than one atomic layer (one molecular layer). Also, for example, in step A, by setting the thickness of the adsorption layer of the first gas formed on the surface of the underlayer 200a to more than one atomic layer (one molecular layer), it is possible to control the etching amount of the underlayer 200a in step B at a level of, for example, more than one atomic layer (one molecular layer). Furthermore, for example, by setting the thickness of the adsorption layer of the first gas formed on the surface of the base 200a to several atomic layers (several molecular layers) in step A, it becomes possible to control the amount of etching of the base 200a in step B, for example, at the level of several atomic layers (several molecular layers).

[0122] Since the portion where the first modified layer 200b is formed in step A serves as the base for the etching seeds 200c to be generated on the surface of the base 200a in step B, the amount of the etching seeds 200c to be generated in step B, i.e., the etching amount, can be controlled by the amount of the compound to be generated on the surface of the base 200a in step A.

[0123] For example, in step A, by setting the thickness of the compound generated on the surface of the underlayer 200a to one atomic layer (one molecular layer) or less, it is possible to control the etching amount (etching thickness) of the underlayer 200a in step B at a level of, for example, one atomic layer (one molecular layer) or less. Also, for example, in step A, by setting the thickness of the compound generated on the surface of the underlayer 200a to less than one atomic layer (one molecular layer), it is possible to control the etching amount of the underlayer 200a in step B at a level of, for example, less than one atomic layer (one molecular layer). Also, for example, in step A, by setting the thickness of the compound generated on the surface of the underlayer 200a to a thickness exceeding one atomic layer (one molecular layer), it is possible to control the etching amount of the underlayer 200a in step B at a level exceeding one atomic layer (one molecular layer). Furthermore, for example, by making the thickness of the compound generated on the surface of the base 200a in step A to be several atomic layers (several molecular layers), it becomes possible to control the amount of etching of the base 200a in step B, for example, at the level of several atomic layers (several molecular layers).

[0124] In step A, the reaction forming the first modified layer 200b, i.e., the modification reaction, can be saturated. As a result, in step A, the first modified layer 200b can be formed more uniformly in the surface of the underlayer 200a. As a result, in step B, etching species can be generated more uniformly in the surface of the underlayer 200a, and the uniformity of the etching amount of the underlayer 200a can be further improved. This further enables conformal etching processing. As a method for saturating the modification reaction, a method for saturating the modification reaction by adsorption can further improve the controllability of the etching amount than a method for saturating the modification reaction by compound generation. For example, in step A, by saturating the modification reaction by adsorption, it becomes easy to make the thickness of the adsorption layer of the first gas formed on the surface of the underlayer 200a one atomic layer (one molecular layer) or less.

[0125] In step B, not only a part of the surface of the underlayer 200a is etched, but also a second modified layer 200d that can be removed by the first gas can be formed on the surface of the underlayer 200a after the surface is etched. In this case, in step A after the second cycle, the second modified layer 200d is removed by supplying the first gas to the wafer 200, and the first modified layer 200b can be formed on the surface of the underlayer 200a that is exposed by removing the second modified layer 200d. That is, in step A after the second cycle, the second modified layer 200d formed in step B can be removed, and the first modified layer 200b can be formed on the surface of the underlayer 200a. This makes it possible to improve the total etching rate of the underlayer 200a when a cycle in which steps A and B are not performed simultaneously is repeated.

[0126] The first gas preferably contains one or more of the gases exemplified above as the first gas, and the second gas preferably contains one or more of the gases exemplified above as the second gas. However, the first gas and the second gas must have different molecular structures. In the case of such a combination of the first gas and the second gas, the above-mentioned effect is particularly pronounced.

[0127] By performing a cycle of non-simultaneous execution of step A and step B a predetermined number of times to etch the underlayer 200a in a non-plasma atmosphere, it is possible to improve the controllability of the amount of etching. In addition, by performing this etching process in a non-plasma atmosphere, it is possible to prevent damage caused by plasma to the wafer 200 and the film formed on the surface of the wafer 200.

[0128] <Other Aspects of the Disclosure> Although the embodiments of the present disclosure have been specifically described above, the present disclosure is not limited to the above embodiments and can be modified in various ways without departing from the spirit and scope of the present disclosure.

[0129] For example, the base 200a as the first film, which is the film to be etched, may be at least any one of a silicon nitride film (SiN film), a silicon carbonitride film (SiCN film), a nitrogen-rich silicon oxynitride film (SiON film), a nitrogen-rich silicon oxycarbonitride film (SiOCN film), a silicon boron nitride film (SiBN film), a silicon boron carbonitride film (SiBCN film), a boron nitride film (BN film), a titanium nitride film (TiN film), a tungsten nitride film (WN film), a tungsten film (W film), a molybdenum film (Mo film), a silicon film (Si film), a germanium film (Ge film), and a silicon germanium film (SiGe film).

[0130] In addition, the O-containing film such as a SiON film or a SiOCN film as the first film is preferably an N-rich film, that is, a film in which the N concentration is higher than the O concentration in the film. That is, the SiON film or the SiOCN film is preferably an N-rich SiON film or an N-rich SiOCN film. Even if the first film contains O in addition to N, as long as the N concentration is higher than the O concentration, the first film can be sufficiently etched by the method of the above-mentioned embodiment.

[0131] As described above, the base 200a as the first film may be a nitrogen-containing film such as a silicon-based nitride film (silicon-based nitrogen-containing film) such as a SiN film, a SiCN film, an N-rich SiON film, an N-rich SiOCN film, a SiBN film, a SiBCN film, etc., a boron-based nitride film (boron-based nitrogen-containing film) such as a BN film, etc., a metal-based nitride film (metal-based nitrogen-containing film) such as a TiN film, a WN film, etc., a metal film (transition metal film, transition metal simple film) such as a W film, a Mo film, etc., or a semiconductor film such as a Si film, a Ge film, a SiGe film, etc.

[0132] Even if the base 200a as the first film is at least any one of these films, the same effects as those of the above embodiment can be obtained.

[0133] Also, for example, as in the process sequence shown below, a pre-processing (step C) of supplying a third gas to the wafer 200 may be performed before supplying the first gas to the wafer 200. This makes it possible to promote the formation of the first modified layer 200b on the surface of the base 200a exposed on the surface of the wafer 200.

[0134] (Third gas → First gas → Second gas) × n

[0135] The following describes the processing procedure and processing conditions in step C. Note that the processing procedures and processing conditions other than step C may be the same as those in the above-mentioned embodiment.

[0136] [Step C] In step C, the third gas is supplied to the wafer 200 in the processing chamber 201, that is, to the wafer 200 having the base 200a exposed on its surface as the first film.

[0137] Specifically, the valve 243c is opened to allow the third gas to flow into the gas supply pipe 232c. The flow rate of the third gas is adjusted by the MFC 241c, and the third gas is supplied into the processing chamber 201 via the nozzle 249c, flows over the surface of the wafer 200, and is exhausted from the exhaust port 231a. At this time, the third gas is supplied to the wafer 200. Also, at this time, the valves 243d to 243f may be opened to supply an inert gas into the processing chamber 201 via each of the nozzles 249a to 249c.

[0138] Supplying the third gas to the wafer 200 under conditions described below makes it possible to pre-treat the surface of the underlayer 200a exposed on the surface of the wafer 200. For example, it is possible to pre-treat the surface of the underlayer 200a so that the surface of the underlayer 200a functions as an adsorption site for the first gas.

[0139] After the surface of the base 200a is pre-treated, the valve 243c is closed to stop the supply of the third gas into the processing chamber 201. Then, the processing chamber 201 is evacuated to remove gas remaining in the processing chamber 201 from the processing chamber 201. At this time, the valves 243d to 243f are opened to supply an inert gas into the processing chamber 201 through the nozzles 249a to 249c. The inert gas supplied from the nozzles 249a to 249c acts as a purge gas, thereby purging the processing chamber 201 (purging). Purging with an inert gas may not be performed.

[0140] The process conditions for supplying the third gas in step C are as follows: Processing temperature: 30~300℃ Processing pressure: 5~1000Pa Third gas supply flow rate: 10 to 2000 sccm Third gas supply time: 5 to 1800 seconds Inert gas supply flow rate (per gas supply pipe): 0 to 10,000 sccm Examples are given below.

[0141] There are no particular limitations on the third gas, so long as it is a gas capable of carrying out the above-mentioned pretreatment, that is, a gas capable of forming adsorption sites for the first gas on the surface of the base 200a.

[0142] As the third gas, for example, a gas containing O and H can be used. As the gas containing O and H, for example, H 2 O gas and H 2 O 2 Gases containing O and H can be used. 2 Gas + H 2An O-containing gas and an H-containing gas, such as a gas, can be used. When these gases are used as the third gas, the surface of the base 200a is terminated with hydroxyl groups (OH) in step C. That is, in this case, OH terminations are formed as adsorption sites on the surface of the base 200a. When OH terminations are formed as adsorption sites on the surface of the base 200a, it is preferable to use a gas that reacts with OH terminations as the first gas, and for example, the above-mentioned aminosilane-based gas can be used.

[0143] The third gas may be, for example, a gas containing N and H. The third gas may be, for example, NH 3 Gas and N 2 H 4 Gas and N 2 H 2 Gases, etc. can be used. When these gases are used as the third gas, in step C, the surface of the underlayer 200a is terminated with NH groups. That is, in this case, NH terminations are formed as adsorption sites on the surface of the underlayer 200a. When NH terminations are formed as adsorption sites on the surface of the underlayer 200a, it is preferable to use a gas that reacts with NH terminations as the first gas, and for example, the above-mentioned halosilane gas, alkylhalosilane gas, etc. can be used. In this case, it is preferable to use the above-mentioned chlorosilane gas or alkylchlorosilane gas as the halosilane gas or alkylhalosilane gas.

[0144] As the third gas, for example, a N- and H-containing gas or a N-containing gas that has been plasma-excited can be used. For example, NH 3 Gas, N 2 H 4 Gas, N 2 H 2 Gas, N 2 When a gas containing N and H is used as the third gas by being plasma-excited, NH 3 * , N.H. 2 * , N.H.* In this case, in step C, the surface of the base 200a is terminated with an NH group, and an NH termination is formed as an adsorption site on the surface of the base 200a. In addition, when an N-containing gas is plasma-excited and used as the third gas, N is adsorbed on the surface of the base 200a. 2 * , N * A gas containing active species (e.g., radicals) such as NH is supplied. In this case, in step C, the surface of the underlayer 200a is terminated with N, and N-terminations are formed on the surface of the underlayer 200a as adsorption sites. When NH-terminations are formed on the surface of the underlayer 200a as adsorption sites, it is preferable to use a gas that reacts with NH-terminations as the first gas, and for example, the above-mentioned halosilane gas or alkylhalosilane gas can be used. In this case, it is preferable to use the above-mentioned chlorosilane gas or alkylchlorosilane gas as the halosilane gas or alkylhalosilane gas. In addition, when N-terminations are formed on the surface of the underlayer 200a as adsorption sites, it is preferable to use a gas that reacts with N-terminations as the first gas, and for example, the above-mentioned aminosilane gas can be used.

[0145] According to this embodiment, the same effect as the above embodiment can be obtained. Moreover, according to this embodiment, the adsorption of the first gas to the surface of the base 200a can be promoted, and thus the processing time in step A can be shortened. Furthermore, in step A, the adsorption layer of the first gas can be formed more uniformly in the surface of the base 200a, and further, the density of the adsorption layer of the first gas formed on the surface of the base 200a can be increased, and thus, in step B, the etching seeds can be generated more uniformly in the surface of the base 200a. This further enables conformal etching processing.

[0146] This embodiment is particularly effective when a reforming reaction is caused to occur by adsorption in step A.

[0147] 9(a), a cycle of non-simultaneously performing step A and step B may be performed a predetermined number of times on a wafer 200 having an exposed surface including an underlayer 200a as a first film and an underlayer 200e as a second film made of a material different from that of the underlayer 200a. The underlayer 200a as the first film includes a silicon-based nitrogen-containing film such as a silicon nitride film (SiN film). The underlayer 200e as the second film includes a silicon-based oxygen-containing film such as a silicon oxide film (SiO film).

[0148] The difference between this embodiment and the above-mentioned embodiment is that the present embodiment uses a wafer 200 having the underlayer 200a and the underlayer 200e exposed on the surface, and the etching process in this embodiment can be performed in the same manner as the etching process in the above-mentioned embodiment. That is, the process procedure and the process conditions of the etching process in this embodiment can be the same as the process procedure and the process conditions of the etching process in the above-mentioned embodiment.

[0149] By performing a cycle of non-simultaneous processing of step A and step B for a wafer 200 having the underlayer 200a and the underlayer 200e exposed on the surface a predetermined number of times, it becomes possible to selectively etch the underlayer 200a with respect to the underlayer 200e, as shown in FIG. 9(b) and FIG. 9(c). That is, by performing a cycle of non-simultaneous processing of step A and step B for a wafer 200 having the underlayer 200a and the underlayer 200e exposed on the surface a predetermined number of times, it becomes possible to promote etching of the underlayer 200a while suppressing etching of the underlayer 200e. This is considered to be due to the fact that, in the etching process in the above-mentioned embodiment, the above-mentioned various reactions occur on the surface of the underlayer 200a, but the above-mentioned various reactions are unlikely to occur on the surface of the underlayer 200e. FIG. 9(b) shows the state of the surface of the wafer 200 during the etching process, and FIG. 9(c) shows the state of the surface of the wafer 200 after the etching process is completed.

[0150] According to this embodiment, the underlayer 200a can be etched with a selectivity of 5:1 or more, 10:1 or more, or 20:1 or more to the underlayer 200e. Also, according to this embodiment, the underlayer 200a can be etched with a selectivity of 30:1 or more, 40:1 or more, 50:1 or more, or even more than that to the underlayer 200e. Also, according to this embodiment, depending on the conditions, the underlayer 200a can be etched without substantially etching the underlayer 200e. In this specification, "etching the underlayer 200a with a selectivity of 5:1 or more to the underlayer 200e" means that the etching amount of the underlayer 200a is "5" or more when the etching amount of the underlayer 200e is "1".

[0151] Thus, according to this embodiment, etching of the underlayer 200a can be promoted while suppressing etching of the underlayer 200e, and the underlayer 200a can be etched with high selectivity with respect to the underlayer 200e. That is, according to this embodiment, selective etching, in which a specific film is selectively etched, becomes possible. Furthermore, according to this embodiment, it becomes possible to improve the controllability of the amount of etching in the selective etching.

[0152] In this embodiment, it is preferable that the underlayer 200a includes a nitride film, and the underlayer 200e includes a film other than the nitride film (for example, an oxide film). It is preferable that the underlayer 200a includes a silicon nitride film, and the underlayer 200e includes a film other than the silicon nitride film (for example, a silicon oxide film). It is also preferable that the underlayer 200a includes a nitrogen-containing film, and the underlayer 200e includes a film other than the nitrogen-containing film (for example, an oxygen-containing film). It is also preferable that the underlayer 200a includes a silicon and nitrogen-containing film, and the underlayer 200e includes a film other than the silicon and nitrogen-containing film (for example, a silicon and oxygen-containing film). In the case of such a combination of the underlayer 200a and the underlayer 200e, the above-mentioned effect is particularly remarkable. However, the underlayer 200a may be a film other than the nitride film (silicon nitride film, nitrogen-containing film, silicon and nitrogen-containing film). It is also preferable that the underlayer 200e be a film other than the oxide film (silicon oxide film, oxygen-containing film, silicon and oxygen-containing film).

[0153] For example, the base 200a as the first film may be at least one of a SiN film, a SiCN film, an N-rich SiON film, an N-rich SiOCN film, a SiBN film, a SiBCN film, a BN film, a TiN film, a WN film, a W film, a Mo film, a Si film, a Ge film, and a SiGe film, as in the above-mentioned embodiment. Note that, as in the above-mentioned embodiment, the O-containing film such as a SiON film or a SiOCN film as the first film is preferably an N-rich film, that is, a film in which the N concentration in the film is higher than the O concentration in the film. As described above, the base 200a as the first film may be a nitrogen-containing film such as a silicon-based nitride film (silicon-based nitrogen-containing film) such as a SiN film, a SiCN film, an N-rich SiON film, an N-rich SiOCN film, a SiBN film, a SiBCN film, etc., a boron-based nitride film (boron-based nitrogen-containing film) such as a BN film, etc., a metal-based nitride film (metal-based nitrogen-containing film) such as a TiN film, a WN film, etc., a metal film (transition metal film, transition metal simple film) such as a W film, a Mo film, etc., or a semiconductor film such as a Si film, a Ge film, a SiGe film, etc.

[0154] Furthermore, the base 200e as the second film may be at least any one of a silicon oxide film (SiO film), a silicon oxycarbide film (SiOC film), an oxygen-rich silicon oxynitride film (SiON film), an oxygen-rich silicon oxycarbonitride film (SiOCN film), a titanium oxide film (TiO film), a hafnium oxide film (HfO film), a zirconium oxide film (ZrO film), an aluminum oxide film (AlO film), and an aluminum film (Al film).

[0155] In addition, the O-containing film such as a SiON film or a SiOCN film as the second film is preferably an O-rich film, that is, a film in which the O concentration in the film is higher than the N concentration in the film. That is, the SiON film or the SiOCN film is preferably an O-rich SiON film or an O-rich SiOCN film. Even if the second film contains N in addition to O, if the O concentration is higher than the N concentration, it is possible to suppress the etching of the second film by the method of the above-mentioned aspect.

[0156] As described above, the base 200e as the second film may be an oxygen-containing film such as a silicon-based oxide film (silicon-based oxygen-containing film) such as a SiO film, a SiOC film, an O-rich SiON film, or an O-rich SiOCN film, or a metal-based oxide film (metal-based oxygen-containing film) such as a TiO film, a HfO film, a ZrO film, or an AlO film, or a metal film (non-transition metal film, non-transition metal simple substance film) such as an Al film.

[0157] Also, for example, in addition to the first film (underlying 200a), a plurality of films, such as a second film (underlying 200e) and a third film, may be exposed on the surface of the wafer 200. The films (specifically, the first film, the second film, the third film, etc.) exposed on the surface of the wafer 200 may be any of the films exemplified as the first film and the films exemplified as the second film.

[0158] For example, a SiN film, a SiO film, and a Si film may be exposed on the surface of the wafer 200 as the first film, the second film, and the third film, respectively. In this case, it is possible to selectively etch the SiN film and the Si film with respect to the SiO film. Also, for example, a SiCN film, a SiOC film, and an AlO film may be exposed on the surface of the wafer 200 as the first film, the second film, and the third film, respectively. In this case, it is possible to selectively etch the SiCN film with respect to the SiOC film and the AlO film. Also, for example, an N-rich SiOCN film, an O-rich SiOCN film, an N-rich SiON film, and an O-rich SiON film may be exposed on the surface of the wafer 200 as the first film, the second film, the third film, and the fourth film, respectively. In this case, it is possible to selectively etch the N-rich SiOCN film and the N-rich SiON film with respect to the O-rich SiOCN film and the O-rich SiON film. In these cases, the same effects as those of the above-mentioned embodiment can be obtained.

[0159] It is preferable that the recipes used for each process are prepared individually according to the process contents and stored in the storage device 121c via an electric communication line or an external storage device 123. Then, when starting each process, it is preferable that the CPU 121a appropriately selects an appropriate recipe according to the process contents from among the multiple recipes stored in the storage device 121c. This makes it possible to realize various etching processes with good reproducibility using a single substrate processing device. It is also possible to reduce the burden on the operator and quickly start each process while avoiding operational errors.

[0160] The above-mentioned recipes may not only be newly created, but may also be prepared by modifying an existing recipe that has already been installed in the substrate processing apparatus. When modifying a recipe, the modified recipe may be installed in the substrate processing apparatus via an electric communication line or a recording medium on which the recipe has been recorded. In addition, an existing recipe that has already been installed in the substrate processing apparatus may be directly modified by operating the input / output device 122 provided in the existing substrate processing apparatus.

[0161] In the above-mentioned embodiment, an example of performing an etching process using a batch-type substrate processing apparatus that processes multiple substrates at a time has been described. The present disclosure is not limited to the above-mentioned embodiment, and can be suitably applied to, for example, a case where an etching process is performed using a single-wafer type substrate processing apparatus that processes one or several substrates at a time. In addition, in the above-mentioned embodiment, an example of performing an etching process using a substrate processing apparatus having a hot-wall type processing furnace has been described. The present disclosure is not limited to the above-mentioned embodiment, and can be suitably applied to a case where an etching process is performed using a substrate processing apparatus having a cold-wall type processing furnace.

[0162] When these substrate processing apparatuses are used, the processes can be performed under the same processing procedures and conditions as in the above embodiment, and the same effects as in the above embodiment can be obtained.

[0163] The above-mentioned aspects may be used in appropriate combination. The processing procedures and processing conditions in this case may be the same as those of the above-mentioned aspects. EXAMPLES

[0164] (Reference example 1) Using the above-mentioned substrate processing apparatus, the SiN film and the SiO film exposed on the surface of the wafer were etched using the first gas alone, and the amount of etching was measured. As the first gas, one of the fluorine-based gases exemplified as the first gas in the above-mentioned embodiment was used. The processing conditions were within the range of the processing conditions in the above-mentioned step A, except that the processing temperature was 100°C, 250°C, 350°C, or 400°C.

[0165] Fig. 6 shows the measurement results of the etching amount in Reference Example 1. The horizontal axis of Fig. 6 shows the processing temperature (°C), and the vertical axis of Fig. 6 shows the etching amount (Å) of the SiN film and the SiO film, respectively. In Fig. 6, the ■ marks show the measurement results of the etching amount of the SiO film, and the ● marks show the measurement results of the etching amount of the SiN film.

[0166] 6 shows that in the case of treatment using only the first gas, etching does not proceed for either the SiN film or the SiO film at a treatment temperature of 100 to 250° C. On the other hand, when the treatment temperature exceeds 250° C., etching proceeds for the SiN film and slightly proceeds for the SiO film, even in the case of treatment using only the first gas.

[0167] (Reference example 2) Using the above-mentioned substrate processing apparatus, the SiN film and the SiO film exposed on the surface of the wafer were etched using the second gas alone, and their etching amounts were measured. The second gas was a gas with a molecular structure different from that of the first gas in Reference Example 1, and was one of the fluorine-based gases exemplified as the second gas in the above-mentioned embodiment. The processing conditions were set to predetermined conditions within the range of the processing conditions in the above-mentioned step B, except that the processing temperature was set to 35°C or 100°C.

[0168] Fig. 7 shows the measurement results of the etching amount in Reference Example 2. The horizontal axis of Fig. 7 shows the processing temperature (°C), and the vertical axis of Fig. 7 shows the etching amount (Å) of the SiN film and the SiO film, respectively. In Fig. 7, the ■ marks show the measurement results of the etching amount of the SiO film, and the ● marks show the measurement results of the etching amount of the SiN film.

[0169] From FIG. 7, it can be seen that in the case of treatment with the second gas alone, etching does not proceed for either the SiN film or the SiO film at a treatment temperature of 35 to 100° C. It was confirmed that in the case of treatment with the second gas alone, etching does not tend to proceed for either the SiN film or the SiO film at a treatment temperature of 100 to 250° C. It was also confirmed that when the treatment temperature exceeds 250° C., etching proceeds slightly for both the SiN film and the SiO film even in the case of treatment with the second gas alone, and when the treatment temperature is 400° C. or higher, etching tends to proceed for both the SiN film and the SiO film even in the case of treatment with the second gas alone.

[0170] (Example) Using the above-mentioned substrate processing apparatus, an etching process was performed on the SiN film and SiO film exposed on the surface of the wafer according to the process sequence shown in Fig. 4, and the etching amounts were measured. As the first gas, a gas similar to the first gas in Reference Example 1 was used, and as the second gas, a gas similar to the second gas in Reference Example 2 was used. The process conditions were set to predetermined conditions within the range of the process conditions in the above-mentioned steps A and B, except that the process temperature was set to 100°C.

[0171] FIG. 8 shows the measurement results of the etching amount in the examples. For comparison, FIG. 8 also shows the etching amount when the processing temperature in Reference Examples 1 and 2 was set to 100° C. The vertical axis in FIG. 8 shows the etching amount (Å) of the SiN film and the SiO film, respectively. In FIG. 8, the ■ marks show the measurement results of the SiO film, and the ● marks show the measurement results of the SiN film.

[0172] As shown in Fig. 8, at a processing temperature of 100°C, neither the SiN film nor the SiO film is etched, whether the processing is performed using the first gas alone (Reference Example 1) or the second gas alone (Reference Example 2). On the other hand, in the examples, by performing an etching process according to the processing sequence shown in Fig. 4 at a processing temperature of 100°C, the etching hardly progresses for the SiO film, but an etching amount of nearly 80 Å for the SiN film is obtained. It is noted that in the examples shown in Fig. 8, the SiN film was etched with a selectivity of 35:1 to 45:1 relative to the SiO film.

[0173] Such a difference in the amount of etching, that is, the difference between the amount of etching of the SiO film in Reference Example 1, Reference Example 2, and Examples and the amount of etching of the SiN film in Examples, shows a similar tendency at least within a processing temperature range of 25 to 250° C. Moreover, such a difference in the amount of etching also shows a similar tendency within a range of 250 to 400° C. Therefore, when performing the etching process according to the processing sequence shown in FIG. 4, the processing temperature is preferably within a range of 25 to 400° C., and more preferably within a range of 25 to 250° C.

[0174] <Preferred aspects of the present disclosure> Preferred aspects of the present disclosure will be described below.

[0175] (Appendix 1) According to one aspect of the present disclosure, (a) supplying a first gas to a substrate to form a first modified layer on at least a portion of a surface of a first film exposed on the substrate; (b) supplying a second gas having a molecular structure different from that of the first gas to the substrate to react the second gas with the first modified layer and / or activating the first modified layer with the second gas to generate etching species, and etching at least a portion of the first film with the etching species; a non-simultaneous cycle is performed a predetermined number of times to etch the first film, thereby providing a method for manufacturing a semiconductor device or a method for processing a substrate.

[0176] (Appendix 2) 2. The method according to claim 1, comprising: In (a), at least a portion of the molecules of the first gas are physically or chemically adsorbed onto at least a portion of the surface of the first film to form the first modified layer.

[0177] (Appendix 3) 3. The method according to claim 1 or 2, In (a), at least a part of the molecules of the first gas is chemically reacted with at least a part of the atoms or molecules on the surface of the first film to generate a compound, thereby forming the first modified layer.

[0178] (Appendix 4) The method according to any one of appendix 1 to 3, In (b), the second gas is supplied to the substrate under conditions in which a reaction between the second gas and the first modified layer occurs more predominantly than a reaction between the second gas and the first film.

[0179] (Appendix 5) The method according to any one of appendix 1 to 3, In (b), the second gas is supplied to the substrate under conditions in which a reaction between the second gas and the first modified layer proceeds but a reaction between the second gas and the first film does not proceed.

[0180] (Appendix 6) The method according to any one of appendix 1 to 5, In (b), the second gas is supplied to the substrate under conditions in which activation of the first modified layer by the second gas is dominant over activation of the first film by the second gas.

[0181] (Appendix 7) The method according to any one of appendix 1 to 5, In (b), the second gas is supplied to the substrate under conditions in which activation of the first modified layer by the second gas proceeds and activation of the first film by the second gas does not proceed.

[0182] (Appendix 8) The method according to any one of appendix 1 to 7, In (b), the second gas is supplied to the substrate under conditions in which etching of at least a portion of the first film by the etching species occurs more predominantly than the reaction between the second gas and the first film.

[0183] (Appendix 9) The method according to any one of appendix 1 to 7, In (b), the second gas is supplied to the substrate under conditions in which etching of at least a portion of the first film by the etching species proceeds and reaction between the second gas and the first film does not proceed.

[0184] (Appendix 10) The method according to any one of appendix 1 to 9, In (b), a second modified layer is further formed on at least a portion of the surface of the first film that has been at least partially etched.

[0185] (Appendix 11) 11. The method of claim 10, further comprising: In (a) from the second cycle onwards, the first gas is supplied to the substrate, causing the first gas to react with the second modified layer to remove the second modified layer, and the first modified layer is formed on at least a portion of the surface of the first film from which the second modified layer has been removed.

[0186] (Appendix 12) The method according to any one of appendix 1 to 11, The first film includes a nitrogen-containing film, a transition metal film, or a semiconductor film.

[0187] (Appendix 13) The method according to any one of appendix 1 to 12, A second film is further exposed on the surface of the substrate, The cycle is repeated a predetermined number of times to selectively etch the first film relative to the second film.

[0188] (Appendix 14) 14. The method of claim 13, comprising: The first film includes a nitrogen-containing film, a transition metal film, or a semiconductor film, and the second film includes an oxygen-containing film or a non-transition metal film.

[0189] (Appendix 15) 15. The method according to claim 14, The nitrogen-containing film includes a silicon-based nitrogen-containing film, a boron-based nitrogen-containing film, or a metal-based nitrogen-containing film.

[0190] (Appendix 16) 16. The method according to claim 14 or 15, The oxygen-containing film includes a silicon-based oxygen-containing film or a metal-based oxygen-containing film.

[0191] (Appendix 17) The method according to any one of appendix 13 to 16, By performing the cycle a predetermined number of times, the first film is etched relative to the second film with a selectivity of 5:1 or greater, preferably 10:1 or greater, preferably 20:1 or greater, preferably 30:1 or greater, preferably 40:1 or greater, and preferably 50:1 or greater.

[0192] (Appendix 18) The method according to any one of appendix 1 to 17, The first gas includes one or more of a silicon (Si)-containing gas, a metal-containing gas, an oxygen (O)-containing gas, a nitrogen (N)- and hydrogen (H)-containing gas, a boron (B)-containing gas, a phosphorus (P)-containing gas, and a halogen-containing gas; The second gas includes at least one of a halogen-containing gas and an acetylacetone-based gas.

[0193] (Appendix 19) The method according to any one of appendix 1 to 18, The cycle is repeated a predetermined number of times in a non-plasma atmosphere.

[0194] (Appendix 20) The method according to any one of appendix 1 to 19, The cycle is performed a predetermined number of times under conditions in which the etching reaction of the first film does not proceed continuously when at least one of the first gas and the second gas is present alone. Preferably, the cycle is performed a predetermined number of times under conditions in which the etching reaction of the first film does not proceed continuously when each of the first gas and the second gas is present alone.

[0195] (Appendix 21) According to another aspect of the present disclosure, a processing chamber in which the substrate is processed; a first gas supply system that supplies a first gas to the substrate in the processing chamber; a second gas supply system for supplying a second gas having a molecular structure different from that of the first gas to the substrate in the processing chamber; a temperature regulator for adjusting the temperature of the substrate in the processing chamber; A control unit configured to be able to control the first gas supply system, the second gas supply system, and the temperature regulator so as to perform each process (each step) of Appendix 1 in the processing chamber; A substrate processing apparatus having a

[0196] (Appendix 22) According to yet another aspect of the present disclosure, There is provided a program for causing a substrate processing apparatus to execute each procedure (each step) of Supplementary Note 1 by a computer, or a computer-readable recording medium having the program recorded thereon. [Explanation of symbols]

[0197] 10 First gas (First gas molecules) 12 1st product 14 Second product 20 Second gas (molecule of second gas) 30 products 200 wafers (substrates) 200a Base (first layer) 200b First modified layer 200c Etching species (layer containing etching species) 200d Second modified layer 200e Base (2nd layer)

Claims

1. (a) supplying a first gas to a substrate having a first underlayer and a second underlayer on a surface thereof to form a first layer on at least a portion of the surface of the first underlayer; (b) generating an etching species by at least one of reacting the second gas with the first layer and activating the first layer by the second gas by supplying a second gas having a molecular structure different from that of the first gas to the substrate; and and etching the first underlayer by alternately performing the steps (b) removing at least a portion of a surface of the first base with the etching species, and forming a second layer removable by the first gas on at least a portion of the surface of the first base from which at least a portion of the surface has been removed; In the etching step, a cycle including (a) and (b) is performed multiple times; A substrate processing method in which (a) in the second cycle or later removes the second layer by reacting the first gas with the second layer, and forms the first layer on at least a portion of the surface of the first base from which the second layer has been removed.

2. 2. The substrate processing method according to claim 1, wherein in (a), the first layer is formed by physically or chemically adsorbing at least a portion of the molecules of the first gas onto at least a portion of the surface of the first base.

3. 3. The substrate processing method according to claim 1, wherein in step (a), the first layer is formed by generating a compound through a chemical reaction between at least a portion of the molecules of the first gas and at least a portion of the atoms or molecules of the surface of the first base.

4. The substrate processing method according to any one of claims 1 to 3, wherein in (b), the second gas is supplied to the substrate under conditions in which a reaction between the second gas and the first layer occurs more predominantly than a reaction between the second gas and the first base.

5. The substrate processing method according to any one of claims 1 to 3, wherein in (b), the second gas is supplied to the substrate under conditions in which a reaction between the second gas and the first layer progresses and a reaction between the second gas and the first base does not progress.

6. The substrate processing method according to any one of claims 1 to 5, wherein in (b), the second gas is supplied to the substrate under conditions in which activation of the first layer by the second gas is dominant over activation of the first base by the second gas.

7. The substrate processing method according to any one of claims 1 to 5, wherein in (b), the second gas is supplied to the substrate under conditions in which activation of the first layer by the second gas progresses and activation of the first base by the second gas does not progress.

8. 8. The substrate processing method according to claim 1, further comprising: supplying the second gas to the substrate under conditions in which a reaction between the etching species and at least a portion of the first base occurs more predominantly than a reaction between the second gas and the first base.

9. The substrate processing method according to any one of claims 1 to 7, wherein in (b), the second gas is supplied to the substrate under conditions in which a reaction between the etching species and at least a part of the first base proceeds and a reaction between the second gas and the first base does not proceed.

10. 10. The substrate processing method according to claim 1, wherein the first underlayer includes a nitrogen-containing film, a transition metal film, or a semiconductor film.

11. 11. The substrate processing method according to claim 1, wherein in the etching step, the first underlayer is selectively etched with respect to the second underlayer.

12. The substrate processing method according to claim 11 , wherein the first underlayer includes a nitrogen-containing film, a transition metal film, or a semiconductor film, and the second underlayer includes an oxygen-containing film or a non-transition metal film.

13. The substrate processing method according to claim 12 , wherein the nitrogen-containing film includes a silicon-based nitrogen-containing film, a boron-based nitrogen-containing film, or a metal-based nitrogen-containing film.

14. 14. The substrate processing method according to claim 12, wherein the oxygen-containing film includes a silicon-based oxygen-containing film or a metal-based oxygen-containing film.

15. 15. The substrate processing method according to claim 11, wherein in the etching step, the first underlayer is etched with a selectivity of 5:1 or more to the second underlayer.

16. the first gas includes one or more of a silicon-containing gas, a metal-containing gas, an oxygen-containing gas, a nitrogen- and hydrogen-containing gas, a boron-containing gas, a phosphorus-containing gas, and a halogen-containing gas; 16. The substrate processing method according to claim 1, wherein the second gas contains at least one of a halogen-containing gas and an acetylacetone-based gas.

17. The substrate processing method according to any one of claims 1 to 16, wherein the etching is carried out in a non-plasma atmosphere.

18. (a) supplying a first gas to a substrate having a first underlayer and a second underlayer on a surface thereof to form a first layer on at least a portion of the surface of the first underlayer; (b) generating an etching species by at least one of reacting the second gas with the first layer and activating the first layer by the second gas by supplying a second gas having a molecular structure different from that of the first gas to the substrate; and and etching the first underlayer by alternately performing the steps (b) removing at least a portion of a surface of the first base with the etching species, and forming a second layer removable by the first gas on at least a portion of the surface of the first base from which at least a portion of the surface has been removed; In the etching step, a cycle including (a) and (b) is performed multiple times; In (a) in the second cycle or later, the first gas is reacted with the second layer to remove the second layer, and the first layer is formed on at least a portion of the surface of the first base from which the second layer has been removed.

19. a first gas supply system that supplies a first gas to the substrate; a second gas supply system that supplies a second gas having a molecular structure different from that of the first gas to the substrate; A temperature regulator for adjusting the temperature of the substrate; a control unit configured to be capable of controlling the first gas supply system, the second gas supply system, and the temperature regulator so as to: (a) perform a process of etching the first underlayer by alternately performing a process of supplying the first gas to a substrate having a first underlayer and a second underlayer on a surface thereof to form a first layer on at least a portion of a surface of the first underlayer; and (b) perform a process of supplying the second gas to the substrate to generate etching species by at least one of reacting the second gas with the first layer and activating the first layer with the second gas, wherein in (b), at least a portion of the surface of the first underlayer is removed by the etching species, and a second layer removable by the first gas is formed on at least a portion of the surface of the first underlayer from which at least a portion of the surface has been removed, and the etching process includes a plurality of cycles including (a) and (b), and in (a) from a second cycle onward, the first gas reacts with the second layer to remove the second layer, and the first layer is formed on at least a portion of the surface of the first underlayer from which the second layer has been removed; A substrate processing apparatus comprising:

20. (a) supplying a first gas to a substrate having a first underlayer and a second underlayer on a surface thereof to form a first layer on at least a portion of a surface of the first underlayer; (b) generating an etching species by at least one of supplying a second gas having a molecular structure different from that of the first gas to the substrate, thereby reacting the second gas with the first layer and activating the first layer with the second gas; and and etching the first underlayer by alternately performing the steps. (b) removing at least a portion of a surface of the first base with the etching species, and forming a second layer removable by the first gas on at least a portion of the surface of the first base from which at least a portion of the surface has been removed; The etching step includes performing a cycle including (a) and (b) multiple times; In the step (a) in the second or subsequent cycles, the first gas is reacted with the second layer to remove the second layer, and the first layer is formed on at least a portion of the surface of the first base from which the second layer has been removed; A program for causing a computer to execute the above in a substrate processing apparatus.

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