Processing method, method for manufacturing semiconductor device, processing device and program

Abstract

To provide a technology capable of effectively performing selective processing on the desired surface.SOLUTION: A processing method comprises (a) the step of: preparing a substrate having a first surface and a second surface made of a different material from the first surface, in which a first oxide film is formed on the first surface and a second oxide film is formed on the second surface; and (b) removing the second oxide film formed on the second surface while leaving the first oxide film formed on the first surface by exposing the substrate to an etchant.SELECTED DRAWING: Figure 4D

Description

[Technical Field]

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

[0002] As one step in the manufacturing process of a semiconductor device, a process of selectively growing and forming a film on a specific surface among multiple types of surfaces of different materials exposed on the surface of a substrate (hereinafter, this process is also referred to as selective growth or selective film formation) may be performed (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-106242 [Patent Document 2] Japanese Patent Publication No. 2020-155452 [Patent Document 3] Japanese Patent Publication No. 2020-155607 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that enables selective treatment to be effectively performed on a desired surface. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, (a) preparing a substrate having a first surface and a second surface made of a material different from that of the first surface, a first oxide film formed on the first surface, and a second oxide film formed on the second surface; (b) exposing the substrate to an etching agent to remove the second oxide film formed on the second surface while leaving the first oxide film formed on the first surface; The present invention provides a technique having the following. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to effectively perform selective processing on a desired surface. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of a vertical processing furnace of a processing apparatus suitably used in one embodiment of the present disclosure, showing a processing furnace 202 portion in vertical cross section. [Figure 2] FIG. 2 is a schematic configuration diagram of a vertical processing furnace of a processing apparatus suitably used in one embodiment of the present disclosure, and is a cross-sectional view of the processing furnace 202 portion taken along line AA in FIG. [Figure 3] FIG. 3 is a schematic configuration diagram of the controller 121 of the processing device suitably used in one embodiment of the present disclosure, and is a block diagram showing the control system of the controller 121. [Figure 4A] FIG. 4A is a schematic cross-sectional view showing a surface portion of a wafer having native oxide films formed on the first and second surfaces. [Figure 4B] FIG. 4B is a schematic cross-sectional view showing the surface portion of the wafer after the native oxide films formed on the first and second surfaces have been removed by performing step C from the state of FIG. 4A. [Figure 4C] FIG. 4C is a schematic cross-sectional view showing the surface portion of the wafer after step A is performed from the state of FIG. 4B to form a first oxide film on the first surface and a second oxide film on the second surface. [Figure 4D] FIG. 4D is a schematic cross-sectional view showing the surface portion of the wafer after the second oxide film formed on the second surface has been selectively removed by performing step B from the state of FIG. 4C. [Figure 4E] Figure 4E is a schematic cross-sectional view showing the surface portion of the wafer after performing step D from the state of Figure 4D to modify the surface so as to form an inhibitor layer on the surface of the first oxide film formed on the first surface. [Figure 4F]FIG. 4F is a schematic cross-sectional view showing the surface portion of the wafer after a film has been formed on the second surface by performing step E from the state of FIG. 4E. [Figure 5] FIG. 5 is a graph showing the measurement results of the thickness of the film formed on the first surface and the thickness of the film formed on the second surface for evaluation samples 1 and 2. DETAILED DESCRIPTION OF THE INVENTION

[0008] (1) Embodiment 1 Hereinafter, a first embodiment of the present disclosure will be described mainly with reference to Figures 1 to 3 and 4A to 4F. Note that the drawings used in the following description are all schematic, and the dimensional relationships, ratios, etc. of elements shown in the drawings do not necessarily match those of reality. Furthermore, the dimensional relationships, ratios, etc. of elements between multiple drawings do not necessarily match.

[0009] (1.1) Configuration of the processing device As shown in Fig. 1, the processing furnace 202 of the processing apparatus has a heater 207 as a temperature regulator (heating unit). The heater 207 is cylindrical and is installed vertically by being supported by a holding plate. The heater 207 functions as an energy imparting unit that imparts energy to the gas, and also functions as an activation mechanism (excitation unit) when the gas is activated (excited) by heat.

[0010] A reaction tube 203 is disposed concentrically with the heater 207 inside the heater 207. The reaction tube 203 is made of a heat-resistant material such as quartz (SiO2) or silicon carbide (SiC) and has a cylindrical shape with a closed upper end and an open lower end. 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 has a cylindrical shape with open upper and lower ends. 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 between the manifold 209 and the reaction tube 203 as a sealing member. The reaction tube 203 is installed vertically, similar to 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 portion of the processing vessel. The processing chamber 201 is configured to be able to accommodate wafers 200 as substrates. In the processing chamber 201, processing of the wafers 200 is performed.

[0011] Nozzles 249a to 249c serving as first to third supply units are respectively provided in the processing chamber 201 so as to penetrate the sidewall of the manifold 209. 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.

[0012] Gas supply pipes 232a-232c are provided, in order from the upstream side of the gas flow, with mass flow controllers (MFCs) 241a-241c, which are flow rate control devices (flow rate control parts), and valves 243a-243c, which are on-off valves. Gas supply pipes 232d, 232e, and 232h are connected to the gas supply pipe 232a downstream of the valve 243a. Gas supply pipes 232f and 232g are connected to the gas supply pipes 232b and 232c downstream of the valves 243b and 243c, respectively. Gas supply pipes 232d-232h are provided, in order from the upstream side of the gas flow, with MFCs 241d-241h and valves 243d-243h. Gas supply pipes 232a-232h are made of a metal material, such as SUS.

[0013] As shown in FIG. 2, the nozzles 249a to 249c are respectively provided in an annular space between the inner wall of the reaction tube 203 and the wafers 200 in a plan view, extending from the lower part to the upper part of the inner wall of the reaction tube 203 and rising upward in the arrangement direction of the wafers 200. That is, the nozzles 249a to 249c are respectively provided in regions horizontally surrounding the wafer arrangement region on the sides of the wafer arrangement region where the wafers 200 are arranged, and extending 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 line L passing through the nozzle 249b and the center of the exhaust port 231a along the inner wall of the reaction tube 203 (the outer periphery of the wafers 200) from both sides. The line L also passes through the nozzle 249b and the center of the wafer 200. In other words, the nozzle 249c can be said to be 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 as the axis of symmetry. Gas supply holes 250a to 250c for supplying gas are provided on the side surfaces of the nozzles 249a to 249c, respectively. Each of the gas supply holes 250a to 250c opens to face (face) the exhaust port 231a in a plan view, and is able to supply gas toward the wafers 200. A plurality of the gas supply holes 250a to 250c are provided from the bottom to the top of the reaction tube 203.

[0014] From the gas supply pipe 232a, a raw material is supplied through the MFC 241a, the valve 243a, and the nozzle 249a into the processing chamber 201. The raw material is used as one of the film forming agents.

[0015] A reactant 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 reactant is used as one of the film forming agents.

[0016] An oxidizing agent is supplied from the gas supply pipe 232c into the processing chamber 201 via an MFC 241c, a valve 243c, and a nozzle 249c.

[0017] The modifying agent is supplied from the gas supply pipe 232d into the processing chamber 201 via the MFC 241d, the valve 243d, the gas supply pipe 232a, and the nozzle 249a.

[0018] An etching agent is supplied from the gas supply pipe 232h into the processing chamber 201 via the MFC 241h, the valve 243h, the gas supply pipe 232a, and the nozzle 249a.

[0019] Inert gases are supplied from the gas supply pipes 232e to 232g through the MFCs 241e to 241g, the valves 243e to 243g, the gas supply pipes 232a to 232c, and the nozzles 249a to 249c into the processing chamber 201. The inert gases act as purge gases, carrier gases, dilution gases, etc.

[0020] The raw material supply system (raw material exposure system) is mainly composed of the gas supply pipe 232a, MFC 241a, and valve 243a. The reactant supply system (reactant exposure system) is mainly composed of the gas supply pipe 232b, MFC 241b, and valve 243b. The oxidant supply system (oxidant exposure system) is mainly composed of the gas supply pipe 232c, MFC 241c, and valve 243c. The raw material supply system and reactant supply system are also referred to as film-forming agent supply system (film-forming agent exposure system). The modifying agent supply system (modifying agent exposure system) is mainly composed of the gas supply pipe 232d, MFC 241d, and valve 243d. The etching agent supply system (etching agent exposure system) is mainly composed of the gas supply pipe 232h, MFC 241h, and valve 243h. An inert gas supply system is mainly composed of the gas supply pipes 232e to 232g, the MFCs 241e to 241g, and the valves 243e to 243g.

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

[0022] An exhaust port 231a for exhausting the atmosphere inside the processing chamber 201 is provided at the bottom of the sidewall of the reaction tube 203. As shown in FIG. 2, the exhaust port 231a is provided at a position facing (opposite) the nozzles 249a-249c (gas supply holes 250a-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 bottom to the top, i.e., along the wafer arrangement area. An exhaust pipe 231 is connected to the exhaust port 231a. A vacuum pump 246 serving as a vacuum exhaust device is connected to the exhaust pipe 231 via a pressure sensor 245 serving as a pressure detector (pressure detection unit) for detecting the pressure inside the processing chamber 201 and an APC (Auto Pressure Controller) valve 244 serving as a pressure regulator (pressure adjustment unit). The APC valve 244 is configured to be able to evacuate and stop the evacuation of the processing chamber 201 by opening and closing the valve while the vacuum pump 246 is operating, and further, to be able to adjust the pressure inside 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 operating. 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.

[0023] Below the manifold 209, a seal cap 219 is provided as a furnace port cover capable of airtightly 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 sealing member that abuts against the lower end of the manifold 209. Below the seal cap 219, a rotation mechanism 267 is provided to rotate the boat 217 (described later). A rotation shaft 255 of the rotation mechanism 267 penetrates the seal cap 219 and is connected to the boat 217. The rotation mechanism 267 is configured to rotate the boat 217, thereby rotating the wafers 200. The seal cap 219 is configured to be vertically raised and lowered 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) that transfers the wafers 200 into and out of the processing chamber 201 by raising and lowering the seal cap 219.

[0024] 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 removed from the processing chamber 201. The shutter 219s is made of a metal material such as SUS and has a disk shape. An O-ring 220c is provided on the upper surface of the shutter 219s as a sealing member that abuts against 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.

[0025] The boat 217 as a substrate support is configured to support a plurality of wafers 200, for example, 25 to 200 wafers 200, in a horizontal position and aligned vertically with their centers aligned, i.e., arranged at intervals, in multiple stages. 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, also made of a heat-resistant material such as quartz or SiC, are supported in multiple stages.

[0026] A temperature sensor 263 serving as a temperature detector is installed inside the reaction tube 203. By adjusting the power supply to the heater 207 based on the temperature information detected by the temperature sensor 263, the temperature inside the processing chamber 201 can be adjusted to a desired temperature distribution. The temperature sensor 263 is installed along the inner wall of the reaction tube 203.

[0027] As shown in FIG. 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. An external storage device 123 can also be connected to the controller 121. The processing device may be configured to include one or more control units. That is, control for performing the processing sequence described below may be performed using one control unit or multiple control units. The multiple control units may be configured as a control system connected to each other via a wired or wireless communication network, and control for performing the processing sequence described below may be performed by the entire control system. In this specification, when the term "control section" is used, it may include one control section, multiple control sections, or a control system configured by multiple control sections.

[0028] The storage device 121c is configured with, for example, a flash memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), etc. Control programs for controlling the operation of the processing device, process recipes describing the procedures and conditions of the processes described below, etc., are readably recorded and stored in the storage device 121c. The process recipe is a combination of the procedures described below that are executed by the controller 121 in the processing device (processing system) to obtain a predetermined result, and functions as a program. Hereinafter, the process recipes, control programs, etc. are collectively referred to simply as programs (program products). The process recipes are also simply referred to as recipes. In this specification, the term "program" may refer to a recipe alone, a control program alone, or both. The RAM 121b is configured as a memory area (work area) for temporarily storing programs, data, etc. read by the CPU 121a.

[0029] The I / O port 121d is connected to the above-mentioned MFCs 241a to 241h, valves 243a to 243h, 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.

[0030] 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 input of an operation command from the input / output device 122. The CPU 121a is configured to control, in accordance with the contents of the read recipe, the flow rate adjustment operation of various substances (various gases) by the MFCs 241a to 241h, the opening and closing operation of the valves 243a to 243h, 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, and the like.

[0031] The controller 121 can be configured by installing the above-mentioned program recorded and stored in the external storage device 123 into a computer. The external storage device 123 includes, for example, a magnetic disk such as an HDD, an optical disk such as a CD, or a semiconductor memory such as a USB memory or an SSD. The storage device 121c and the external storage device 123 are configured as computer-readable recording media. Hereinafter, these will be collectively referred to 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. Note that 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.

[0032] (1.2) Treatment process An example of a substrate processing method (processing method) as one step in a semiconductor device manufacturing process (manufacturing method) using the processing apparatus described above, i.e., a processing sequence for selectively forming a film on the second surface of a wafer 200 serving as a substrate, out of a first surface and a second surface thereof, will be described mainly with reference to FIGS. 4A to 4F. In the first embodiment, a case will be described in which the first surface (first base) includes a silicon film (Si film) and the second surface (second base) includes a silicon nitride film (SiN film). That is, in the first embodiment, an example will be described in which the first surface includes silicon (Si) as a semiconductor element and the second surface includes silicon (Si) and nitrogen (N) as semiconductor elements. In the following description, the operation of each component constituting the processing apparatus is controlled by a controller 121. The processing apparatus will also be referred to as a substrate processing apparatus, a film formation processing apparatus, or a film formation apparatus. The processing method will also be referred to as a substrate processing method, a film formation processing method, or a film formation method.

[0033] 4A, the wafer 200 has a first underlayer and a second underlayer on its surface. A native oxide film is formed on the first surface of the first underlayer and the second surface of the second underlayer.

[0034] In the processing sequence of the first embodiment, (a) Step A of preparing a wafer 200 having a first surface and a second surface made of a material different from that of the first surface, a first oxide film formed on the first surface, and a second oxide film formed on the second surface; (b) Step B of exposing the wafer 200 to an etching agent to remove the second oxide film formed on the second surface while leaving the first oxide film formed on the first surface; Do the following.

[0035] In the processing sequence of the first embodiment, (c) Step C of removing native oxide films formed on the first and second surfaces by exposing the wafer 200 before step A to an etching agent; (d) Step D of modifying the surface of the wafer 200 after step B by exposing the wafer 200 to a modifying agent to form an inhibitor layer on the surface of the first oxide film on the first surface; (e) Step E of forming a film on the second surface by exposing the wafer 200 after step D to a film-forming agent; Further implementation will be carried out.

[0036] The term "wafer" used in this specification may refer to the wafer itself or to a laminate of the wafer and a predetermined layer or film formed on its surface. The term "surface of a wafer" used in this specification may refer to the surface of the wafer itself or to the surface of a predetermined layer or the like formed on the wafer. When described in this specification, "forming a predetermined layer on a wafer" may mean forming a predetermined layer directly on the surface of the wafer itself or forming a predetermined layer on a layer or the like formed on the wafer. When used in this specification, the term "substrate" is synonymous with the term "wafer".

[0037] The term "film" as used herein includes at least one of a continuous layer and a discontinuous layer. For example, a native oxide film, a first oxide film, a second oxide film, an inhibitor layer, and a film may each include a continuous layer, a discontinuous layer, or both.

[0038] The term "agent" as used herein includes at least one of a gaseous substance and a liquid substance. A liquid substance includes a mist substance. That is, each of the raw material, reactant, oxidizing agent, modifier, and etching agent may include a gaseous substance, a liquid substance such as a mist substance, or both.

[0039] The term "inhibitor" as used herein may refer to a film-formation inhibitory action (adsorption inhibitory action, reaction inhibitory action), a modifier, or a residue derived from a modifier, for example, at least a part of the molecular structure of a molecule that constitutes a modifier, or may be used as a general term for all of these.

[0040] (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, and the lower end opening of the manifold 209 is opened (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. In this manner, the wafers 200 are prepared in the processing chamber 201.

[0041] (pressure and temperature regulation) After the boat loading is completed, the processing chamber 201, i.e., the space in which the wafers 200 are present, is evacuated (reduced pressure exhausted) by the vacuum pump 246 so that the interior of the processing chamber 201 is at 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. Furthermore, the wafers 200 inside the processing chamber 201 are heated by the heater 207 so that the processing temperature is at a desired processing temperature. At this time, the power supply to the heater 207 is feedback-controlled based on temperature information detected by the temperature sensor 263 so that the processing chamber 201 has a desired temperature distribution. Furthermore, the rotation mechanism 267 starts to rotate the wafers 200. The evacuation inside the processing chamber 201 and the heating and rotation of the wafers 200 are all continued at least until the processing of the wafers 200 is completed.

[0042] (1.2.1) Step C Then, step C is performed. In step C, the wafer 200 before step A is subjected to is exposed to an etching agent to remove the native oxide films formed on the first and second surfaces.

[0043] Specifically, the valve 243h is opened to allow the etching agent to flow into the gas supply pipe 232h. The flow rate of the etching agent is adjusted by the MFC 241h, and the etching agent is supplied into the processing chamber 201 via the gas supply pipe 232a and the nozzle 249a, and is exhausted from the exhaust port 231a. At this time, the etching agent is supplied to the wafer 200 from the side of the wafer 200, and the wafer 200 is exposed to the etching agent. At this time, the valves 243e to 243g may be opened to supply an inert gas into the processing chamber 201 via the nozzles 249a to 249c, respectively.

[0044] By performing step C, the native oxide film formed on the first surface and the second surface can be removed to expose the first surface and the second surface, as shown in Fig. 4B. As a result, in step A, uniform processing can be performed on the first surface and also on the second surface.

[0045] The etching agent can be a substance containing fluorine (F), i.e., a fluorine-based substance, such as a fluorine-containing gas. Examples of the fluorine-containing gas include fluorine (F) gas, hydrogen fluoride (HF) gas, chlorine trifluoride (ClF) gas, chlorine fluoride (ClF) gas, nitrogen fluoride (NF) gas, and nitrosyl fluoride (FNO) gas. Other examples include hydrogen and fluorine-containing gases, chlorine and fluorine-containing gases, nitrogen and fluorine-containing gases, and fluorine, nitrogen, and oxygen-containing gases. Examples of the etching agent include fluorine-containing substances, hydrogen and fluorine-containing substances, chlorine and fluorine-containing substances, nitrogen and fluorine-containing substances, and fluorine, nitrogen, and oxygen-containing substances. Examples of the etching agent include halogens, hydrogen halides, interhalogen compounds, nitrogen halides, and nitrosyl halides. Examples of the etching agent include fluorine-based substances such as a hydrogen fluoride (HF) aqueous solution. One or more of these can be used as the etching agent.

[0046] As the inert gas, for example, nitrogen (N2) gas or a rare gas can be used. As the rare gas, argon (Ar) gas, helium (He) gas, neon (Ne) gas, xenon (Xe) gas, etc. can be used. As the inert gas, one or more of these can be used. This also applies to each step described later.

[0047] In step C, the processing conditions when a fluorine-containing gas is used as the etching agent are as follows: Treatment temperature: room temperature (25°C) to 400°C, preferably 50 to 250°C Treatment pressure: 1 to 13332 Pa, preferably 1 to 1333 Pa Treatment time: 1 second to 120 minutes, preferably 1 minute to 60 minutes Etching agent supply flow rate: 0.001 to 2 slm Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm is exemplified.

[0048] In this specification, when a numerical range such as "25 to 400°C" is expressed, both the lower limit and the upper limit are included in the range. For example, "25 to 400°C" means "25°C or higher and 400°C or lower." The same applies to other numerical ranges. In this specification, the processing temperature refers to the temperature of the wafer 200 or the temperature inside the processing chamber 201, and the processing pressure refers to the pressure inside the processing chamber 201. The processing time refers to the time the processing continues. In addition, when the supply flow rate includes 0 slm (sccm), 0 slm (sccm) means that the gas is not supplied. These terms also apply to the following description.

[0049] In step C, the processing conditions when using an HF aqueous solution as an etching agent are as follows: Treatment temperature: 10 to 60°C, preferably 15 to 40°C Treatment time: 1 to 600 seconds, preferably 1 to 300 seconds Etching agent concentration: 0.1 to 5%, preferably 0.5 to 2% is exemplified.

[0050] After removing the native oxide films formed on the first and second surfaces, the valve 243h is closed to stop the supply of the etching agent into the processing chamber 201. Then, the processing chamber 201 is evacuated to remove gaseous substances remaining in the processing chamber 201. At this time, the valves 243e to 243g 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.

[0051] Note that if the native oxide films formed on the first and second surfaces of the wafer 200 have been removed in advance and the wafer 200 is used in such a state, step C can be omitted. In this case, step A, which will be described later, will be performed after the pressure and temperature adjustments.

[0052] (1.2.2) Step A In step A, a wafer 200 is prepared, which has a first surface and a second surface, a first oxide film formed on the first surface, and a second oxide film formed on the second surface.

[0053] In the first embodiment, the first oxide film and the second oxide film are formed by oxidizing the first surface and the second surface by exposing the wafer 200 to an oxidizing agent. The oxidation of the first surface and the second surface is performed under conditions such that the thickness of the first oxide film formed on the first surface is greater than the thickness of the second oxide film formed on the second surface.

[0054] Specifically, wafer 200 is exposed to an oxidizing agent after step C. As a result, wafer 200 is prepared with a first oxide film formed on its first surface and a second oxide film formed on its second surface, as shown in FIG.

[0055] Specifically, the valve 243c is opened to allow an oxidizing agent to flow into the gas supply pipe 232c. The flow rate of the oxidizing agent is adjusted by the MFC 241c, and the oxidizing agent is supplied into the processing chamber 201 via the gas supply pipe 232c and the nozzle 249c, and is exhausted from the exhaust port 231a. At this time, the oxidizing agent is supplied to the wafer 200 from the side of the wafer 200, and the wafer 200 is exposed to the oxidizing agent. At this time, the valves 243e to 243g may be opened to supply an inert gas into the processing chamber 201 via the nozzles 249a to 249c, respectively.

[0056] The processing conditions for supplying the oxidizing agent in step A are as follows: Treatment temperature: 200 to 800°C, preferably 300 to 600°C Treatment pressure: 1 to 105,000 Pa, preferably 1,000 to 105,000 Pa Treatment time: 1 to 11,000 seconds, preferably 5 to 7,200 seconds Oxidant supply flow rate: 0.01 to 10 slm, preferably 0.1 to 5 slm Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm is exemplified.

[0057] If the treatment temperature exceeds 800°C, the second oxide film formed on the second surface may become too thick, making it difficult to subsequently remove the second oxide film using an etching agent. Furthermore, stronger etching conditions are required when removing the second oxide film using an etching agent, which may raise concerns about etching damage. Furthermore, since the first and second surfaces are directly oxidized at high temperatures, there may be concerns about damage to each surface. Setting the treatment temperature to 800°C or less makes it possible to resolve these issues. Setting the treatment temperature to 600°C or less makes it possible to effectively resolve these issues.

[0058] If the treatment temperature is below 200°C, the oxidation of the first surface will be insufficient, and the first oxide film formed on the first surface will be too thin, which may prevent the inhibitor layer from being properly formed on the surface of the first oxide film. Furthermore, the first oxide film may not function adequately as a protective film for the first surface, and the first surface may be damaged, particularly when a fluorine-containing substance is used to form the inhibitor layer. These problems can be solved by setting the treatment temperature to 200°C or higher. These problems can be effectively solved by setting the treatment temperature to 300°C or higher.

[0059] For these reasons, in step A, the treatment temperature is preferably 200°C or higher and 800°C or lower, and more preferably 200°C or higher and 600°C or lower.

[0060] Examples of oxidizing agents include oxygen (O2) gas, ozone (O3) gas, O2 gas + hydrogen (H2) gas, O2 gas + deuterium (D2) gas, O3 gas + H2 gas, O3 gas + D2 gas, hydrogen peroxide (H2O2) gas, water vapor (H2O gas), nitrous oxide (N2O) gas, nitric oxide (NO) gas, nitrogen dioxide (NO2) gas, carbon dioxide (CO2) gas, and carbon monoxide (CO) gas. Oxygen- and hydrogen-containing gases, oxygen- and deuterium-containing gases, oxygen- and nitrogen-containing gases, and oxygen- and carbon-containing gases can be used. One or more of these can be used as the oxidizing agent. Here, the combination of two gases, such as "O2 gas + H2 gas," refers to a mixture of O2 gas and H2 gas. When 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 supplied separately into the processing chamber 201 through different supply pipes and then mixed (postmixed) in the processing chamber 201.

[0061] In the first embodiment, the wafer 200 is exposed to an oxidizing agent under conditions that oxidize both the first surface and the second surface, i.e., under conditions that perform non-selective oxidation. Therefore, the restrictions on the processing conditions in step A of the first embodiment can be relaxed compared to when the wafer 200 is exposed to an oxidizing agent under conditions that oxidize the first surface without oxidizing the second surface, i.e., under conditions that perform selective oxidation, and the degree of freedom in the processing conditions can be increased.

[0062] The thickness of the first oxide film thus formed is thicker than the thickness of the second oxide film, which is, for example, about 1 to 20 Å, and the thickness of the second oxide film is, for example, about 1 to 15 Å.

[0063] In the first embodiment, the first oxide film contains a semiconductor element, and the first oxide film has a composition that is rich in the semiconductor element relative to the stoichiometric composition. For example, a silicon oxide film with a stoichiometric composition can be expressed as SiO2. On the other hand, when the semiconductor element contained in the first surface is Si, the silicon oxide film with a composition that is rich in the semiconductor element relative to the stoichiometric composition can be expressed as, for example, SiO1.9 , SiO 1.8 , SiO 1.7 In the first embodiment, for example, the first oxide film contains Si as a semiconductor element, and the first oxide film is a silicon oxide film (e.g., SiO 1.9 , SiO 1.8 , SiO 1.7 etc.)

[0064] In the first embodiment, the first oxide film and the second oxide film contain semiconductor elements, and the first oxide film has a composition richer in semiconductor elements than the second oxide film. "The first oxide film has a composition richer in semiconductor elements than the second oxide film" means that the atomic ratio of semiconductor elements among the elements constituting the first oxide film is greater than the atomic ratio of semiconductor elements among the elements constituting the second oxide film. For example, when the semiconductor element is Si, SiO 1.7 The oxide film represented by SiO 1.9 In the first embodiment, the first oxide film has a composition richer in semiconductor elements (Si-rich) than the second oxide film. In the first embodiment, the reason why the first oxide film has a composition richer in semiconductor elements than the second oxide film is believed to be that the first oxide film is formed by oxidizing the first surface containing Si, and the second oxide film is formed by oxidizing the second surface containing Si and N. It is believed that when the first surface containing Si is oxidized, the first oxide film rich in semiconductor elements is formed, and when the second surface containing Si and N is oxidized, the second oxide film is formed, the composition of which on the surface side is SiO2 and the composition of which on the bottom side is SiON.

[0065] After the first surface and the second surface are oxidized, the valve 243c is closed to stop the supply of the oxidizing agent into the processing chamber 201. Then, gaseous substances remaining in the processing chamber 201 are removed from the processing chamber 201 by a processing procedure similar to the purging in step C.

[0066] (1.2.3) Step B Then, step B is performed. In step B, the wafer 200 is exposed to an etching agent to remove the second oxide film formed on the second surface while leaving the first oxide film formed on the first surface.

[0067] By performing step B, the first oxide film formed on the first surface can be left and the second surface can be exposed, as shown in Figure 4D. At this time, the secondary action of the etching agent can adjust and optimize the adsorption sites on the surface of the first oxide film. Therefore, in step D, the adsorption of inhibitor molecules on the surface of the first oxide film can be promoted, making it possible to effectively selectively form an inhibitor layer on the surface of the first oxide film. As a result, in the film formation in step E, the film formation inhibitory effect on the first surface can be enhanced, making it possible to effectively selectively form a film on the second surface. Furthermore, in step B, the removal accuracy of the second oxide film can be improved, making it possible to improve the smoothness of the second surface.

[0068] As the etching agent, the same etching agent as that used in step C can be used, and the etching treatment at this time can be performed according to the same treatment procedure as the etching treatment in step C.

[0069] In step B, the processing conditions when a fluorine-containing gas is used as the etching agent are as follows: Treatment temperature: room temperature (25°C) to 400°C, preferably 50 to 250°C Treatment pressure: 1 to 13332 Pa, preferably 1 to 1333 Pa Treatment time: 1 second to 120 minutes, preferably 1 minute to 60 minutes Etching agent supply flow rate: 0.001 to 2 slm Inert gas supply flow rate (per gas supply pipe): 0 to 50 slm is exemplified.

[0070] In step B, the processing conditions when using an HF aqueous solution as an etching agent are as follows: Treatment temperature: 10 to 60°C, preferably 15 to 40°C Treatment time: 1 to 600 seconds, preferably 1 to 300 seconds Etching agent concentration: 0.01 to 1%, preferably 0.05 to 0.5% is exemplified.

[0071] It is preferable to expose wafer 200 to the etching agent for a time period different from that of wafer 200 in step B. This allows for improved control of the etching agent treatment in step B and the etching agent treatment in step C. If the etching agent used in step B contains an aqueous HF solution, i.e., contains HF and HO, it becomes possible to more effectively adjust and optimize the adsorption sites on the surface of the first oxide film formed on the first surface by a secondary action of the etching agent when removing the second oxide film formed on the second surface by etching.

[0072] The etching agent used in step B and the etching agent used in step C preferably contain the same substance X, but the concentration of substance X in the etching agent used in step B is different from the concentration of substance X in the etching agent used in step C. This allows for improved control of the etching agent processes in step B and step C. For example, by making the concentration of substance X in the etching agent used in step B lower than the concentration of substance X in the etching agent used in step C, it is possible to remove the second oxide film while effectively leaving the first oxide film in step B, and it is also possible to effectively remove the native oxide film in step C. In this case, by exposing the wafer 200 to the etching agent for a longer period of time in step B than in step C, it is possible to effectively remove the second oxide film in step B while maintaining these effects. In these cases, it is more preferable that substance X contains HF. For example, it is preferable that the etching agent used in step B contains an HF aqueous solution or HF gas, and the etching agent used in step C contains an HF aqueous solution or HF gas. It is more preferable that the etching agent used in step B is an aqueous HF solution, that is, a solution containing HF and H2O.

[0073] Here, the etching rate of the first oxide film is lower than that of the second oxide film. This is thought to be due to the fact that the first oxide film has a semiconductor-element-rich composition compared to the second oxide film. Specifically, the first oxide film formed by oxidizing the first surface containing Si tends to be semiconductor-element-rich, i.e., Si-rich. When the first oxide film becomes Si-rich, its etching resistance increases and the first oxide film becomes less susceptible to etching. That is, its etching rate decreases. In contrast, the second oxide film formed by oxidizing the second surface containing Si and N tends to contain SiO2 of a stoichiometric composition at least on its surface. When the second oxide film contains SiO2 at least on its surface, the second oxide film is etched at a typical etching rate. That is, when both the first oxide film and the second oxide film are exposed to an etching agent simultaneously under similar conditions, the first oxide film formed on the first surface remains unetched, while most of the second oxide film formed on the second surface is etched. This is thought to be mainly due to the high etching resistance of the first oxide film and its resistance to etching. That is, the main reason is thought to be that the etching rate of the first oxide film is lower than that of the second oxide film, that is, the etching resistance of the first oxide film is higher than that of the second oxide film.

[0074] After removing the second oxide film while leaving the first oxide film, the supply of the etching agent into the processing chamber 201 is stopped. Then, gaseous substances remaining in the processing chamber 201 are removed from the processing chamber 201 by a processing procedure similar to the purging in step C.

[0075] Note that step B can be omitted when the second oxide film formed on the second surface of wafer 200 is somewhat thinner (e.g., extremely thin) than the first oxide film, or when the density of OH terminations on the surface of the second oxide film is somewhat lower (e.g., extremely lower) than the density of OH terminations on the surface of the first oxide film. In this case, step A is performed, followed by step D, which will be described later.

[0076] (1.2.4) Step D In step D, the wafer 200 after step B is exposed to a modifying agent to modify the surface so as to form an inhibitor layer on the surface of the first oxide film on the first surface.

[0077] By performing step D, an inhibitor layer is formed on the surface of the first oxide film out of the surface of the first oxide film and the second surface, as shown in FIG. 4E.

[0078] Specifically, the valve 243d is opened to allow the modifying agent to flow into the gas supply pipe 232d. The flow rate of the modifying agent is adjusted by the MFC 241d, and the modifying agent is supplied into the processing chamber 201 via the gas supply pipe 232a and the nozzle 249a, and then exhausted from the exhaust port 231a. At this time, the modifying agent is supplied to the wafer 200 from the side of the wafer 200, and the wafer 200 is exposed to the modifying agent. At least one of a silicon (Si)-containing gas and a fluorine (F)-containing gas can be used as the modifying agent. At this time, the valves 243e to 243g may be opened to supply an inert gas into the processing chamber 201 via each of the nozzles 249a to 249c.

[0079] The processing conditions for supplying a Si-containing gas as a modifier in step D are as follows: Treatment temperature: room temperature (25°C) to 500°C, preferably room temperature to 250°C Treatment pressure: 5 to 2000 Pa, preferably 10 to 1000 Pa Processing time: 1 second to 120 minutes, preferably 30 seconds to 60 minutes Si-containing gas supply flow rate: 0.001 to 3 slm, preferably 0.001 to 0.5 slm Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm is exemplified.

[0080] The processing conditions for supplying the F-containing gas as a modifying agent in step D are as follows: Treatment temperature: room temperature (25°C) to 300°C, preferably room temperature to 200°C Treatment pressure: 1 to 2000 Pa, preferably 1 to 1000 Pa Processing time: 1 second to 60 minutes F-containing gas supply flow rate: 0.001 to 2 slm, preferably 0.001 to 0.5 slm Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm is exemplified.

[0081] By exposing the wafer 200 to the modifying agent under the above-described conditions, inhibitor molecules, which are at least a part of the molecular structure of the molecules constituting the modifying agent, are adsorbed onto the surface of the first oxide film remaining on the first surface of the wafer 200, thereby selectively forming an inhibitor layer on that surface. This allows the surface of the first oxide film on the first surface to be terminated with inhibitor molecules, which are at least a part of the molecular structure of the molecules constituting the modifying agent. The inhibitor layer functions to prevent the adsorption of the raw material (film-forming agent) onto the first surface of the wafer 200 and inhibit the formation of a film on the first surface in Step E, which will be described later. The inhibitor molecules are also referred to as film-formation-inhibiting molecules (adsorption-inhibiting molecules, reaction-inhibiting molecules). The inhibitor layer is also referred to as a film-formation-inhibiting layer (adsorption-inhibiting layer, reaction-inhibiting layer).

[0082] In this step, at least a portion of the molecular structure of the molecules constituting the modifier may be adsorbed to a portion of the second surface, but the amount of adsorption is small, and the amount of adsorption to the surface of the first oxide film at the first surface is overwhelmingly greater. Such selective (preferential) adsorption is possible because OH terminations that serve as adsorption sites are formed throughout the first surface, i.e., the first oxide film, while OH terminations are not formed in most areas of the second surface.

[0083] In step D, a Si-containing gas, an F-containing gas, or both may be supplied as the modifier. When both a Si-containing gas and an F-containing gas are supplied as the modifier, it is preferable to supply the Si-containing gas first and then the F-containing gas. After supplying the Si-containing gas, purging may be performed before supplying the F-containing gas. By supplying the Si-containing gas first, at least a portion of the molecular structure A of the molecules constituting the Si-containing gas can be adsorbed onto the surface of the first oxide film. By subsequently supplying the F-containing gas, the F-containing gas can react with at least a portion of the molecular structure A adsorbed onto the surface of the first oxide film, thereby adsorbing at least a portion of the molecular structure B of the molecules constituting the F-containing gas onto the surface of the first oxide film. By sequentially supplying the Si-containing gas and the F-containing gas as the modifier, the density of the inhibitor layer, i.e., the density of the inhibitor molecules, can be increased compared to when only the F-containing gas is supplied as the modifier.

[0084] Examples of Si-containing gases that can be used as modifiers include tetrakis(dimethylamino)silane (Si[N(CH3)2]4) gas, tris(dimethylamino)silane (Si[N(CH3)2]3H) gas, bis(diethylamino)silane (Si[N(C2H5)2]2H2) gas, bis(tertiarybutylamino)silane (SiH2[NH(C4H9)]2) gas, (diisobutylamino)silane (SiH3[N(C4H9)2]) gas, and (diisopropylamino)silane (SiH3[N(C3H7)2]) gas, which are substances in which Si is bonded to H and an amino group, i.e., aminosilane-based gases. In addition, as a modifier, for example, a substance in which an amino group and an alkyl group are bonded to Si, i.e., an alkylaminosilane-based gas, such as (dimethylamino)trimethylsilane ((CH3)2NSi(CH3)3) gas, (diethylamino)triethylsilane ((C2H5)2NSi(C2H5)3) gas, (dimethylamino)triethylsilane ((CH3)2NSi(C2H5)3) gas, (diethylamino)trimethylsilane ((C2H5)2NSi(CH3)3) gas, or (dipropylamino)trimethylsilane ((C3H7)2NSi(CH3)3) gas, can be used. These can also be referred to as a substance containing at least one of H and an alkyl group and an amino group. One or more of these can be used as a modifier.

[0085] Examples of F-containing gases that can be used as a modifier include ClF gas, ClF gas, F gas, F + NO gas, ClF + NO gas, NF gas, FNO gas, tungsten hexafluoride (WF) gas, etc. One or more of these can be used as a modifier.

[0086] After the inhibitor layer is formed on the surface of the first oxide film on the first surface, the valve 243d is closed to stop the supply of the modifying agent into the processing chamber 201. Then, gaseous substances remaining in the processing chamber 201 are removed from the processing chamber 201 by a processing procedure similar to the purging in step C.

[0087] (1.2.5) Step E In step E, a film is formed on the second surface by exposing the wafer 200 after step D to a film forming agent. Specifically, in step E, steps E1 and E2 are performed in sequence.

[0088] By performing step E, a film is selectively formed on the second surface of the first surface and the second surface, as shown in FIG. 4F.

[0089] (1.2.5.1) Step E1 In step E1, a raw material is supplied as a film forming agent to the wafer 200 after the surface of the first oxide film on the first surface has been selectively modified.

[0090] Specifically, valve 243a is opened to allow the raw material to flow into gas supply pipe 232a. The raw material has a flow rate adjusted by MFC 241a, is supplied into processing chamber 201 through nozzle 249a, and is exhausted from exhaust port 231a. At this time, the raw material is supplied to wafer 200 from the side of wafer 200, and wafer 200 is exposed to the raw material. At this time, valves 243e to 243g may be opened to supply an inert gas into processing chamber 201 through nozzles 249a to 249c, respectively.

[0091] The processing conditions for supplying the raw material as the film forming agent in step E1 are as follows: Treatment temperature: room temperature (25°C) to 700°C, preferably 350 to 550°C Treatment pressure: 1 to 2000 Pa, preferably 1 to 1333 Pa Treatment time: 1 to 180 seconds, preferably 10 to 120 seconds Raw material supply flow rate: 0.001 to 2 slm, preferably 0.01 to 1 slm Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm is exemplified.

[0092] By supplying the raw material to the wafer 200 under the above conditions, it is possible to selectively adsorb at least a portion of the molecular structure of the molecules constituting the raw material onto the second surface while suppressing adsorption of at least a portion of the molecular structure of the molecules constituting the raw material onto the first surface. As a result, a first layer is selectively formed on the second surface. The first layer contains at least a portion of the molecular structure of the molecules constituting the raw material, which is a residue of the raw material. In other words, the first layer contains at least a portion of the atoms constituting the raw material. When the raw material described below is used, the first layer becomes, for example, a Si-containing layer.

[0093] In this step, at least a portion of the molecular structure of the molecules constituting the raw material may be adsorbed onto a portion of the surface of the first oxide film on the first surface, but the amount of adsorption is small, and the amount of adsorption onto the second surface is overwhelmingly greater. Such selective (preferential) adsorption is possible because an inhibitor layer is formed over the entire first surface, i.e., the first oxide film, while no inhibitor layer is formed in most areas of the second surface.

[0094] After the first layer is formed on the second surface, the valve 243a is closed to stop the supply of raw materials into the processing chamber 201. Then, gases and the like remaining in the processing chamber 201 are removed from the processing chamber 201 by a processing procedure similar to the purging in step C.

[0095] As a raw material, for example, a Si- and halogen-containing gas (Si- and halogen-containing substance) can be used. Examples of halogens include chlorine (Cl), fluorine (F), bromine (Br), and iodine (I). The Si- and halogen-containing gas preferably contains halogen in the form of a chemical bond between Si and halogen. Examples of the Si- and halogen-containing gas include a silane-based gas having a Si-Cl bond, a Si-F bond, a Si-Br bond, or a Si-I bond, i.e., a chlorosilane-based gas, a fluorosilane-based gas, a bromosilane-based gas, or an iodosilane-based gas. The Si- and halogen-containing gas may further contain carbon (C), and in this case, it is preferable that C be contained in the form of a Si-C bond. Examples of the Si- and halogen-containing gas include a silane-based gas containing Si, Cl, and an alkylene group and having a Si-C bond, i.e., an alkylenechlorosilane-based gas. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, and the like. Furthermore, as the Si- and halogen-containing gas, for example, a silane-based gas containing Si, Cl, and an alkyl group and having a Si-C bond, i.e., an alkylchlorosilane-based gas, can be used. The alkyl group includes a methyl group, an ethyl group, a propyl group, a butyl group, etc. The Si- and halogen-containing gas may further contain O, and in this case, it is preferable that O is contained in the form of a Si-O bond, for example, in the form of a siloxane bond (Si-O-Si bond). As the Si- and halogen-containing gas, for example, a silane-based gas containing Si, Cl, and a siloxane bond, i.e., a chlorosiloxane-based gas, can be used.

[0096] Examples of usable raw materials include 1,1,3,3-tetrachloro-1,3-disilacyclobutane (C2H4Cl4Si2), 1,1,2,2-tetrachloro-1,2-dimethyldisilane ((CH3)2Si2Cl4), 1,2-dichloro-1,1,2,2-tetramethyldisilane ((CH3)4Si2Cl2), bis(trichlorosilyl)methane ((SiCl3)2CH2), 1,2-bis(trichlorosilyl)ethane ((SiCl3)2C2H4), etc. Examples of usable first raw materials include monochlorosilane (SiH3Cl), dichlorosilane (SiH2Cl2), trichlorosilane (SiHCl3), tetrachlorosilane (SiCl4), hexachlorodisilane (Si2Cl6), octachlorotrisilane (Si3Cl8), etc. As raw materials, for example, hexachlorodisiloxane (Cl3Si-O-SiCl3), octachlorotrisiloxane (Cl3Si-O-SiCl2-O-SiCl3), etc. can be used. As raw materials, for example, tetrafluorosilane (SiF4), difluorosilane (SiH2F2), tetrabromosilane (SiBr4), dibromosilane (SiH2Br2), tetraiodosilane (SiI4), diiodosilane (SiH2I2), etc. can be used. As raw materials, one or more of these can be used.

[0097] (1.2.5.2) Step E2 In step E2, a reactant is supplied as a film-forming agent to the wafer 200 having the first layer formed on the second surface thereof.

[0098] Specifically, valve 243b is opened to allow the reactant to flow into gas supply pipe 232b. The reactant has its flow rate adjusted by MFC 241b, is supplied into processing chamber 201 via nozzle 249b, and is exhausted from exhaust port 231a. At this time, the reactant is supplied to wafer 200 from the side of wafer 200, and wafer 200 is exposed to the reactant. At this time, valves 243e to 243g may be opened to supply an inert gas into processing chamber 201 via nozzles 249a to 249c, respectively.

[0099] The processing conditions for supplying the reactant as the film-forming agent in step E2 are as follows: Treatment temperature: room temperature (25°C) to 700°C, preferably 350 to 550°C Treatment pressure: 1 to 4000 Pa, preferably 1 to 1333 Pa Treatment time: 1 to 180 seconds, preferably 10 to 120 seconds Reactant supply flow rate: 0.01 to 20 slm, preferably 0.01 to 10 slm Inert gas supply flow rate (per gas supply pipe): 0 to 20 slm is exemplified.

[0100] By supplying a reactant to the wafer 200 under the above-described conditions, at least a portion of the first layer formed on the second surface can be reacted with the reactant, thereby converting the first layer into a second layer. If the reactant contains, for example, an N-containing gas (N-containing substance), at least a portion of the first layer formed on the second surface can be nitrided, and a layer containing Si and N, i.e., a silicon nitride layer (SiN layer), can be formed on the second surface. At this time, the surface of the first oxide film on the first surface is maintained by suppressing nitridation due to the action of the inhibitor layer, etc.

[0101] After the second layer is formed on the second surface, the valve 243b is closed to stop the supply of the reactant into the processing chamber 201. Then, gases and the like remaining in the processing chamber 201 are removed from the processing chamber 201 by a processing procedure similar to the purging in step C.

[0102] As the reactant, for example, an N-containing gas (N-containing substance) can be used. As the N-containing gas (N-containing substance), for example, an N- and H-containing gas or a C- and N-containing gas can be used. As the N- and H-containing gas, for example, a hydrogen nitride-based gas containing an N-H bond can be used. As the C- and N-containing gas, an amine-based gas or an organic hydrazine-based gas can be used.

[0103] Examples of reactants that can be used include ammonia (NH3), hydrazine (N2H4), diazene (N2H2), and N3H8. Examples of reactants that can be used include monoethylamine (C2H5NH2), diethylamine ((C2H5)2NH), triethylamine ((C2H5)3N), monomethylamine (CH3NH2), dimethylamine ((CH3)2NH), and trimethylamine ((CH3)3N). Examples of reactants that can be used include monomethylhydrazine ((CH3)HN2H2), dimethylhydrazine ((CH3)2N2H2), and trimethylhydrazine ((CH3)2N2(CH3)H). One or more of these can be used as the reactant.

[0104] [Implemented a specified number of times] By performing a cycle including the above-described steps E1 and E2, for example, a cycle in which steps E1 and E2 are alternately (non-simultaneously) performed a predetermined number of times (n times, where n is an integer of 1 or 2 or greater), a film can be selectively formed on the second surface of the first and second surfaces of wafer 200, as shown in FIG. 4F. As described above, when the reactant includes, for example, an N-containing gas, a silicon nitride film (SiN film) is formed on the second surface. The above-described cycle is preferably repeated multiple times. That is, it is preferable to set the thickness of the second layer formed per cycle to be thinner than the desired film thickness, and to repeat the above-described cycle multiple times until the film formed by stacking the second layer reaches the desired film thickness.

[0105] Note that when steps E1 and E2 are performed, the inhibitor layer present on the surface of the first oxide film is maintained on the surface of the first oxide film, thereby suppressing the growth of a film on the surface of the first oxide film. However, if the inhibitor layer is not sufficiently formed on the surface of the first oxide film due to some factor, the formation and growth of a film on the surface of the first oxide film may be very slight. However, even in this case, the thickness of the film formed on the surface of the first oxide film will be much thinner than the thickness of the film formed on the second surface. In this specification, the phrase "selectively (preferentially) forming a film on the second surface" includes not only the case where no film is formed on the surface of the first oxide film on the first surface and a film is formed only on the second surface, but also the case where a very thin film is formed on the surface of the first oxide film and a much thicker film is formed on the second surface.

[0106] In step E, it is desirable that the thickness of the film formed on the second surface is, for example, 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 5 nm or less, and more preferably 1.5 nm or more and 3 nm or less.

[0107] In step E, a Si-containing film other than a SiN film may be formed. Examples of the Si-containing film include a silicon film (Si film), a silicon carbonitride film (SiCN film), a silicon boronitride film (SiBN film), a silicon boron carbonitride film (SiBCN film), a silicon oxycarbonitride film (SiOCN film), a silicon oxycarbide film (SiOC film), a silicon oxynitride film (SiON film), and a silicon oxide film (SiO film). In addition to the Si-containing film, a metal-containing film may be formed in step E. Examples of metal-containing films include an aluminum film (Al film), a titanium film (Ti film), a hafnium film (Hf film), a zirconium film (Zr film), a tantalum film (Ta film), a tungsten film (W film), a molybdenum film (Mo film), a ruthenium film (Ru film), an aluminum nitride film (AlN film), a titanium nitride film (TiN film), a hafnium nitride film (HfN film), a zirconium nitride film (ZrN film), a tantalum nitride film (TaN film), a tungsten nitride film (WN film), a molybdenum nitride film (MoN film), an aluminum oxide film (AlO film), a titanium oxide film (TiO film), a hafnium oxide film (HfO film), a zirconium oxide film (ZrO film), a tantalum oxide film (TaO film), a tungsten oxide film (WO film), a molybdenum oxide film (MoO film), and a ruthenium oxide film (RuO film).

[0108] (After purging and atmospheric pressure recovery) After the formation of the film on the second surface of the wafer 200 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 gases 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 (atmospheric pressure return).

[0109] (Boat unloading and wafer discharge) Thereafter, 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, supported by the boat 217, are unloaded from the lower end of the manifold 209 to the outside of the reaction tube 203 (boat unloading). After the boat unloading, the shutter 219s is moved, and the opening at the lower end of the manifold 209 is sealed by the shutter 219s via the O-ring 220c (shutter close). After being unloaded to the outside of the reaction tube 203, the processed wafers 200 are removed from the boat 217 (wafer discharge).

[0110] (1.3) Effects of the First Embodiment According to the first embodiment, one or more of the following effects can be obtained.

[0111] In the processing method according to the first embodiment, by performing steps A and B, a state in which a first oxide film is formed on the first surface and the second surface is exposed can be efficiently, effectively, and accurately created. Furthermore, the secondary action of the etching agent can adjust and optimize the adsorption sites on the surface of the first oxide film formed on the first surface. This makes it possible to effectively selectively form an inhibitor layer on the surface of the first oxide film formed on the first surface, and effectively form a film on the second surface. In other words, it becomes possible to effectively perform selective processing on a desired surface.

[0112] In the processing method according to the first embodiment, when the first oxide film and the second oxide film are formed on the first surface and the second surface, respectively, the composition of the first oxide film and the composition of the second oxide film can be made different. This makes it possible to make the etching resistance of the first oxide film different from the etching resistance of the second oxide film, and to make the etching resistance of the first oxide film higher than the etching resistance of the second oxide film. This makes it possible to effectively remove the second oxide film while leaving the first oxide film when exposing the wafer 200 to an etching agent.

[0113] In the processing method according to the first embodiment, when the wafer 200 is exposed to an etching agent, it is possible to effectively remove the second oxide film by etching with high precision while leaving the first oxide film.

[0114] In the processing method according to the first embodiment, it is possible to effectively make the etching resistance of the first oxide film higher than the etching resistance of the second oxide film.

[0115] In the processing method according to the first embodiment, by removing the native oxide film that has formed unevenly on the first surface and the second surface under uncontrolled conditions, it is possible to improve the uniformity of the film thickness of the first oxide film and the second oxide film that are formed on the first surface and the second surface, respectively. Furthermore, by making the etching resistance of the first oxide film and the second oxide film that are formed on the first surface and the second surface, respectively, that are exposed by removing the native oxide film different from each other, it is possible to effectively make the etching resistance of the first oxide film higher than the etching resistance of the second oxide film.

[0116] In the processing method according to the first embodiment, when the second oxide film formed on the second surface is removed by etching, the secondary action of the etching agent effectively adjusts and optimizes the adsorption sites on the surface of the first oxide film formed on the first surface.

[0117] The processing method according to the first embodiment makes it possible to improve the controllability of each of the etching agent treatments in step B and step C. When the etching agent used in step B contains an HF aqueous solution (hydrogen fluoride aqueous solution), it becomes possible to more effectively adjust and optimize the adsorption sites on the surface of the first oxide film formed on the first surface by a secondary action of the etching agent when removing the second oxide film formed on the second surface by etching.

[0118] In the processing method according to the first embodiment, it is possible to effectively perform selective film formation on the second surface, that is, it is possible to effectively improve the selectivity in selective film formation.

[0119] (2) Other embodiments The processing sequence of the first embodiment can be modified as in the other embodiments shown below. These embodiments can be combined as desired. Unless otherwise specified, the processing procedures and processing conditions in each step of each embodiment can be the same as the processing procedures and processing conditions in each step of the above-described processing sequence.

[0120] (2.1) Embodiment 2 In the processing sequence of embodiment 1, an example in which the first surface includes a Si film and the second surface includes a SiN film has been described, but the present disclosure is not limited thereto. The present disclosure is also applicable to cases in which the first surface includes a semiconductor material other than a Si film and the second surface includes a nitride other than a SiN film. The present disclosure is also applicable to cases in which the first surface includes a semiconductor material other than a Si film and the second surface includes a semiconductor element other than a SiN film and a material containing nitrogen. The first surface is preferably composed of a material that is more easily oxidized than the second surface, i.e., a material that is less resistant to oxidation than the second surface. For example, the first surface is preferably composed of a material with a higher Si atomic concentration and / or a lower N atomic concentration than the second surface. Furthermore, the first and second surfaces are preferably composed of materials such that the etching rate of the first oxide film formed by oxidizing the first surface is lower than the etching rate of the second oxide film formed by oxidizing the second surface. That is, the first surface and the second surface are preferably made of a material that provides a first oxide film formed by oxidizing the first surface with a higher etching resistance than a second oxide film formed by oxidizing the second surface. The first surface and the second surface are preferably made of a material that satisfies these relationships, and the first surface and the second surface may be made of at least one of a Si film and a SiN film, a silicon-containing film such as single crystal Si (Si wafer), a SiCN film, a SiBN film, a SiBCN film, a SiOCN film, a SiOC film, or a SiON film, or a metal-containing film such as an Al film, a Ti film, a Hf film, a Zr film, a Ta film, a W film, a Mo film, a Ru film, an AlN film, a TiN film, a HfN film, a ZrN film, a TaN film, a WN film, or a MoN film. The second embodiment also provides the same effects as the first embodiment.

[0121] (2.2) Embodiment 3 In the processing sequence of the first embodiment, an example has been described in which step C, step A, step B, step D, and step E are performed in this order, but the present disclosure is not limited to this.

[0122] For example, if the native oxide films formed on the first and second surfaces of the wafer 200 have been removed in advance and the wafer 200 is kept in that state, step C can be omitted. In that case, steps A, B, D, and E are performed in this order.

[0123] Furthermore, for example, if the second oxide film formed on the second surface of wafer 200 is somewhat thinner (e.g., extremely thin) than the first oxide film, or if the density of OH terminations on the surface of the second oxide film is somewhat lower (e.g., extremely low) than the density of OH terminations on the surface of the first oxide film, step B can be omitted. In such cases, steps C, A, D, and E are performed in this order. In such cases, if step C can be omitted, steps A, D, and E are performed in this order. In these cases, inhibitor layers are formed on the surfaces of the first oxide film and the second oxide film in step D, but the density of the inhibitor layer formed on the surface of the second oxide film is lower than the density of the inhibitor layer formed on the surface of the first oxide film. As a result, in step E, by performing a cycle including steps E1 and E2 a predetermined number of times, the inhibitor layer formed on the surface of the second oxide film is removed and / or neutralized by the action of the film-forming agent (raw material, reactant), and then a film is formed on the surface of the second oxide film starting from that portion.

[0124] In these cases, the same effects as those of the first embodiment can be obtained.

[0125] (2.3) Embodiment 4 In addition, in the first embodiment, an example has been described in which the above-described processing sequence is performed in the same processing chamber of the same processing apparatus (in-situ). The present disclosure is not limited to the first embodiment, and for example, one step and another step of the above-described processing sequence may be performed in different processing chambers of different processing apparatuses (ex-situ), or may be performed in different processing chambers of the same processing apparatus. In these cases, the same effects as those of the first embodiment can be obtained.

[0126] In the various cases described above, if a series of steps are performed in-situ, the wafer 200 is not exposed to the atmosphere during the process, and the wafer 200 can be processed consistently while being kept under vacuum, allowing for stable processing. Also, if some steps are performed ex-situ, the temperature inside each processing chamber can be set in advance to, for example, the processing temperature for each step or a temperature close to that temperature, thereby shortening the time required for temperature adjustment and enabling an improvement in throughput, i.e., productivity.

[0127] It is preferable that the recipes used for each process are individually prepared according to the process content and recorded 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 content from the multiple recipes recorded and stored in the storage device 121c. This enables the processing device to reproducibly form films with various film types, composition ratios, film qualities, and film thicknesses. It also reduces the burden on the operator, prevents operational errors, and enables each process to be started quickly.

[0128] The above-mentioned recipes do not necessarily have to be newly created, but may be prepared by modifying an existing recipe that has already been installed in the processing device. When modifying a recipe, the modified recipe may be installed in the processing device via an electric communication line or a recording medium on which the recipe has been recorded. Alternatively, an existing recipe that has already been installed in the processing device may be directly modified by operating the input / output device 122 provided in the existing processing device.

[0129] In the first embodiment, an example of forming a film using a batch-type processing apparatus that processes multiple wafers 200 at a time has been described. The present disclosure is not limited to the first embodiment, and can be applied, for example, to a case where a film is formed using a single-wafer processing apparatus that processes one or several wafers 200 at a time. Furthermore, in the first embodiment, an example of forming a film using a processing apparatus having a hot-wall processing furnace has been described. The present disclosure is not limited to the first embodiment, and can be applied to a case where a film is formed using a processing apparatus having a cold-wall processing furnace.

[0130] When using these processing devices, each processing can be performed under the same processing procedures and conditions as in the first to third embodiments, and the same effects as in the first to third embodiments can be obtained.

[0131] It is possible to use an appropriate combination of the first to fourth embodiments. In this case, the processing procedures and processing conditions may be the same as those of the first to fourth embodiments, for example. [Example]

[0132] The present disclosure will be explained in more detail below based on examples, but the present disclosure is not limited to these examples in any way.

[0133] Example 1 A wafer having the same first and second surfaces as those in Embodiment 1 was subjected to the same processing sequence as in Embodiment 1 to form a film on the second surface, thereby producing Evaluation Sample 1 of Example 1. The processing conditions in each step when producing Evaluation Sample 1 were set to predetermined conditions within the range of processing conditions in each step of Embodiment 1. In Example 1, the first surface was the surface of a Si film, the second surface was the surface of a SiN film, and the film formed on the second surface was a SiN film.

[0134] <Reference example 1> A wafer having the same first and second surfaces as those of Embodiment 1 was subjected to a processing sequence in which only step B of the processing sequence of Embodiment 1 was omitted, and a film was formed on the second surface, thereby producing evaluation sample 2 of Reference Example 1. The processing conditions in each step when producing evaluation sample 2 were the same as the processing conditions in each step except for step B of Example 1 described above. Note that in Reference Example 1, as in Example 1, the first surface was the surface of a Si film, the second surface was the surface of a SiN film, and the film formed on the second surface was a SiN film.

[0135] For each evaluation sample, the thickness of the film formed on the first surface and the thickness of the film formed on the second surface were measured. The results are shown in Figure 5. The horizontal axis of Figure 5 indicates the type of evaluation sample, and the vertical axis indicates the film thickness (arbitrary unit: au). The bar graph on the left of each evaluation sample indicates the thickness of the film formed on the second surface, and the bar graph on the right of each evaluation sample indicates the thickness of the film formed on the first surface.

[0136] 5, it can be seen that in both Evaluation Sample 1 and Evaluation Sample 2, the film formed on the second surface is thicker than the film formed on the first surface, and a film is selectively formed on the second surface. Furthermore, the difference in film thickness between the film formed on the first surface and the film formed on the second surface is greater in Evaluation Sample 1 than in Evaluation Sample 2, at more than 2.5 times, indicating that the selectivity in Evaluation Sample 1 is far higher. From these findings, it was confirmed that both Example 1 and Reference Example 1 were able to selectively form a film, and that Example 1 achieved far higher selectivity than Reference Example 1.

Claims

1. (a) preparing a substrate having a first surface and a second surface made of a material different from that of the first surface, a first oxide film formed on the first surface, and a second oxide film formed on the second surface; (b) exposing the substrate to an etching agent to remove the second oxide film formed on the second surface while leaving the first oxide film formed on the first surface; A processing method comprising:

2. 10. The method of claim 1, wherein the first surface comprises a semiconductor material and the second surface comprises a nitride.

3. 10. The method of claim 1, wherein the first surface comprises a semiconductor element and the second surface comprises a semiconductor element and nitrogen.

4. 2. The method of claim 1, wherein the first surface comprises a silicon film and the second surface comprises a silicon nitride film.

5. 2. The method of claim 1, wherein the first oxide film and the second oxide film are formed by oxidation of the first surface and the second surface by exposing the substrate to an oxidizing agent.

6. 6. The processing method of claim 5, wherein the oxidation of the first surface and the second surface is performed under conditions in which the thickness of the first oxide film formed on the first surface is greater than the thickness of the second oxide film formed on the second surface.

7. 2. The processing method according to claim 1, wherein the first oxide film contains a semiconductor element, and the first oxide film has a composition that is rich in the semiconductor element relative to a stoichiometric composition.

8. 2. The processing method according to claim 1, wherein the first oxide film and the second oxide film contain semiconductor elements, and the first oxide film has a composition richer in semiconductor elements than the second oxide film.

9. 2. The method of claim 1, wherein the etching rate of the first oxide film is lower than the etching rate of the second oxide film.

10. 10. The method of claim 1, further comprising the step of: (c) removing native oxide films formed on the first surface and the second surface by exposing the substrate to an etching agent before performing (a).

11. 11. The method of claim 10, wherein the exposure time of the substrate to the etchant in (b) is different from the exposure time of the substrate to the etchant in (c).

12. the etching agent used in (b) and the etching agent used in (c) comprise the same substance; 11. The method of claim 10, wherein the concentration of the substance in the etching agent used in (b) is made different from the concentration of the substance in the etching agent used in (c).

13. The method of claim 12 wherein the substance comprises HF.

14. The etching agent used in (b) includes an aqueous HF solution or HF gas; The method of claim 10 , wherein the etchant used in (c) comprises an aqueous HF solution or HF gas.

15. The etching agent used in (b) is HF and H ２ The processing method according to any one of claims 1 to 9, further comprising O.

16. 10. The method of claim 1, further comprising the step of: (d) exposing the substrate after (b) to a modifier to modify the surface of the first oxide film on the first surface so as to form an inhibitor layer on the surface of the first oxide film.

17. 17. The method of claim 16, further comprising: (e) exposing the substrate after (d) to a film-forming agent to form a film on the second surface.

18. (a) preparing a substrate having a first surface and a second surface made of a material different from that of the first surface, a first oxide film formed on the first surface, and a second oxide film formed on the second surface; (b) exposing the substrate to an etching agent to remove the second oxide film formed on the second surface while leaving the first oxide film formed on the first surface; A method for manufacturing a semiconductor device having the above structure.

19. a device for preparing a substrate; an etchant exposure system for exposing the substrate to an etchant; a control unit configured to be able to control the device and the etching agent exposure system to perform the following processes: (a) a process of preparing a substrate having a first surface and a second surface made of a material different from that of the first surface, with a first oxide film formed on the first surface and a second oxide film formed on the second surface; and (b) a process of exposing the substrate to the etching agent, thereby removing the second oxide film formed on the second surface while leaving the first oxide film formed on the first surface; A processing device having:

20. (a) preparing a substrate having a first surface and a second surface made of a material different from that of the first surface, a first oxide film formed on the first surface, and a second oxide film formed on the second surface; (b) exposing the substrate to an etching agent to remove the second oxide film formed on the second surface while leaving the first oxide film formed on the first surface; A program that causes a processing device to execute the above by a computer.

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