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

Abstract

The present invention has a step in which a cycle including (a), (b), and (c) is performed a predetermined number of times so that at least a part of the implementation periods of (a) and (b) overlap each other to etch a film, (a) being a step in which a modifying gas is supplied to the film, (b) being a step in which an inert gas is supplied to the film, and (c) being a step in which an etching gas is supplied to the film.

Description

Technical Field

[0001] This invention relates to a processing method, a method for manufacturing a semiconductor device, a process, and a processing apparatus. Background Technology

[0002] As a step in the manufacturing process of a semiconductor device, there is a step of etching a substrate (see, for example, Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-136221 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] This invention provides a technique that can improve the controllability of etching on a substrate.

[0008] Solution for solving the problem

[0009] According to one aspect of the present invention, a technique is provided that includes the following steps: etching the membrane by repeating a process comprising (a) supplying a modified gas to the membrane, (b) supplying an inert gas to the membrane, and (c) supplying an etching gas to the membrane, such that at least a portion of the implementation period of (a) and the implementation period of (b) overlap for a predetermined number of times.

[0010] Invention Effects

[0011] According to the present invention, the controllability of etching of the substrate can be improved. Attached Figure Description

[0012] Figure 1 This is a schematic structural diagram of the processing apparatus used in a scheme, and is a longitudinal sectional view showing the processing furnace 202 section.

[0013] Figure 2 This is a schematic structural diagram of the processing device used in a solution, and it is based on... Figure 1 The AA-line sectional view shows part of the processing furnace 202.

[0014] Figure 3 This is a schematic structural diagram of the controller 121 of the processing device used in a scheme, and a block diagram representing the control system of the controller 121.

[0015] Figure 4 This is a diagram illustrating the substrate processing sequence of a given scheme.

[0016] Figure 5(a) is an enlarged cross-sectional view of the surface of a wafer 200 with recesses formed by a substrate processing procedure according to a scheme. Figure 5 (b) is an enlarged cross-sectional view of a wafer 200 after a modified gas is supplied to the film 200a formed on the surface of the recess. Figure 5 (c) is an enlarged cross-sectional view of wafer 200 after an inert gas is supplied to film 200a. Figure 5 (d) is a cross-sectional enlarged view of wafer 200 after the film 200a is supplied with etching gas. Detailed Implementation

[0017] <One aspect of the present invention>

[0018] The following is mainly based on Figures 1 to 4 , Figure 5 (a) to Figure 5 (d) One aspect of the present invention will be described. Furthermore, the figures used in the following description are schematic diagrams, and the dimensional relationships and ratios of the elements shown in the figures may not be consistent with reality. Additionally, the dimensional relationships and ratios of the elements may not be consistent between multiple figures.

[0019] (1) Structure of the processing device

[0020] like Figure 1 As shown, the processing furnace 202 of the processing apparatus has a heater 207 as a temperature adjustment unit (heating unit). The heater 207 is cylindrical and is vertically erected by being supported by a holding plate. The heater 207 also functions as an activation mechanism (activation unit) that uses heat to activate (excite) the gas.

[0021] Inside the heater 207, a reaction tube 203 is arranged concentrically with the heater 207. The reaction tube 203 is made of a heat-resistant material such as quartz (SiO2) or silicon carbide (SiC) and is formed into a cylindrical shape that is closed at the top and open at the bottom. Below the reaction tube 203, a manifold 209 is arranged concentrically with the reaction tube 203. The manifold 209 is made of a metal material such as stainless steel (SUS) and is formed into a cylindrical shape that is open at both the top and bottom. The upper end of the manifold 209 engages with the lower end of the reaction tube 203 and serves to support the reaction tube 203. An O-ring 220a is provided between the manifold 209 and the reaction tube 203 as a sealing component. The reaction tube 203 is vertically erected, just like the heater 207. The processing container (reaction container) is mainly composed of the reaction tube 203 and the manifold 209. A processing chamber 201 is formed in the hollow part of the processing container. The processing chamber 201 is configured to accommodate a wafer 200, which serves as a substrate. The wafer 200 is processed within the processing chamber 201.

[0022] Inside the processing chamber 201, nozzles 249a to 249c, serving as the first to third supply units, are respectively installed on the sidewalls of the manifold 209. These nozzles are also referred to as the first nozzle and the third nozzle, respectively. Each nozzle is made of a heat-resistant material such as quartz or SiC. Gas supply pipes 232a to 232c are connected to each nozzle. Nozzles 249a to 249c are different nozzles, and nozzles 249b and 249c are respectively arranged adjacent to nozzle 249a.

[0023] In gas supply pipes 232a-232c, mass flow controllers (MFCs) 241a-241c (flow controllers, flow control units) and valves 243a-243c (on / off valves) are sequentially installed from the upstream side of the airflow. Gas supply pipe 232d is connected downstream of valve 243a in gas supply pipe 232a. Gas supply pipe 232e is connected downstream of valve 243b in gas supply pipe 232b. In gas supply pipes 232d and 232e, MFCs 241d and 241e and valves 243d and 243e are sequentially installed from the upstream side of the airflow. Gas supply pipes 232a-232e are made of a metal material such as SUS.

[0024] like Figure 2 As shown, nozzles 249a to 249c are arranged in a ring-shaped space between the inner wall of the reaction tube 203 and the wafer 200 when viewed from above, and are respectively positioned upright along the inner wall of the reaction tube 203 from bottom to top, facing upwards towards the arrangement direction of the wafer 200. That is, the horizontal regions of nozzles 249a to 249c surrounding the wafer arrangement area on the side of the wafer arrangement area of ​​the wafer 200 are respectively arranged along the wafer arrangement area. When viewed from above, nozzle 249a is positioned opposite the exhaust port 231a (described later) across the center of the wafer 200 in the processing chamber 201. Nozzles 249b and 249c are arranged along the inner wall of the reaction tube 203 (outer periphery of the wafer 200) from both sides, sandwiching a straight line L passing through the center of nozzle 249a and exhaust port 231a. Straight line L is also a straight line passing through the center of nozzle 249a and wafer 200. That is, nozzle 249c can also be positioned on the opposite side of nozzle 249b, separated by a straight line L. Nozzles 249b and 249c are arranged in a linearly symmetrical configuration with straight line L as the axis of symmetry. Gas supply holes 250a to 250c are respectively provided on the side of nozzles 249a to 249c. Gas supply holes 250a to 250c open in a manner opposite (face-to-face) to exhaust port 231a when viewed from above, and can supply gas toward wafer 200. Multiple gas supply holes 250a to 250c are provided from the bottom to the top of reaction tube 203.

[0025] Modified gas is supplied into the processing chamber 201 from the gas supply pipe 232a via MFC 241a, valve 243a, and nozzle 249a.

[0026] Etching gas is supplied to the processing chamber 201 from the gas supply pipe 232b via MFC 241b, valve 243b, and nozzle 249b.

[0027] Inert gas is supplied to the treatment chamber 201 from gas supply pipes 232c-232e via MFCs 241c-241e, valves 243c-243e, gas supply pipes 232a-232c, and nozzles 249a-249c. The inert gas functions as a purge gas, carrier gas, and dilution gas.

[0028] The modified gas supply system (first gas supply system) mainly consists of gas supply pipe 232a, MFC 241a, and valve 243a. The etching gas supply system (third gas supply system) mainly consists of gas supply pipe 232b, MFC 241b, and valve 243b. The inert gas supply system (second gas supply system) mainly consists of gas supply pipes 232c-232e, MFC 241c-241e, and valves 243c-243e.

[0029] In the aforementioned supply systems, any one or all of the supply systems can be configured as an integrated supply system 248, which integrates valves 243a-243e or MFCs 241a-241e, etc. The integrated supply system 248 is connected to gas supply pipes 232a-232e respectively, and is configured to control the supply of various substances (various gases) to the gas supply pipes 232a-232e, i.e., the opening and closing of valves 243a-243e, and flow adjustment based on MFCs 241a-241e, etc., via the controller 121 described later. The integrated supply system 248 is configured as a single or segmented integrated unit, capable of being installed and removed from the gas supply pipes 232a-232e, etc., on a unit-by-unit basis, and is configured to allow for maintenance, replacement, and addition of the integrated supply system 248 on a unit-by-unit basis.

[0030] An exhaust port 231a is provided below the side wall of the reaction tube 203 for exhausting the ambient gas inside the processing chamber 201. For example... Figure 2As shown, the exhaust port 231a, viewed from above, is positioned opposite (face-to-face) the nozzles 249a-249c (gas supply ports 250a-250c) across the wafer 200. The exhaust port 231a may also be positioned along the side wall of the reaction tube 203 from bottom to 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 (which detects the pressure inside the processing chamber 201) and an APC (Auto Pressure Controller) valve 244 (which acts as a pressure regulator). The APC valve 244 is configured to allow for vacuum exhaust or cessation of vacuum exhaust within the processing chamber 201 by opening and closing the valve while the vacuum pump 246 is operating. Furthermore, by adjusting the valve opening based on pressure information detected by the pressure sensor 245 while the vacuum pump 246 is operating, the pressure within the processing chamber 201 can be adjusted. The exhaust system mainly consists of the exhaust pipe 231, the APC valve 244, and the pressure sensor 245. Alternatively, the vacuum pump 246 can be included within the exhaust system.

[0031] Below the manifold 209, a sealing cover 219 (hereinafter referred to as cover 219) is provided, which can airtightly seal the lower opening of the manifold 209 as a furnace opening cover. The cover 219 is made of a metal material such as SUS and is formed in a disc shape. On the upper surface of the cover 219, an O-ring 220b, which serves as a sealing member, abuts against the lower end of the manifold 209. Below the cover 219, a rotation mechanism 267 is provided to rotate the crystal boat 217 (described later). The rotation shaft 255 of the rotation mechanism 267 passes through the cover 219 and is connected to the crystal boat 217. The rotation mechanism 267 is configured to rotate the wafer 200 by rotating the crystal boat 217. The cover 219 is configured to move vertically by a crystal boat lifter 115 (hereinafter referred to as lifter 115), which serves as a lifting mechanism and is provided outside the reaction tube 203. The lifter 115 is configured as a conveying device (conveying mechanism) for moving the wafer 200 in and out of the processing chamber 201 by lifting the cover 219.

[0032] Below the manifold 209, a baffle 219s, serving as a furnace opening cover, is provided. This baffle can airtightly seal the lower opening of the manifold 209 while the cover 219 is lowered and the crystal boat 217 is removed from the processing chamber 201. The baffle 219s is made of a metal material such as SUS and is formed in a disc shape. On the upper surface of the baffle 219s, an O-ring 220c, acting as a sealing member, abuts against the lower end of the manifold 209. The opening and closing action (lifting or rotating action, etc.) of the baffle 219s is controlled by a baffle opening and closing mechanism 115s.

[0033] The crystal boat 217, serving as a substrate support, is configured to support multiple layers of wafers 200, for example, 25 to 200 wafers, arranged horizontally and aligned with each other in a vertical direction, i.e., spaced apart. The crystal boat 217 is made of a heat-resistant material such as quartz or SiC. Multiple layers of heat-insulating plates 218, also made of heat-resistant materials such as quartz or SiC, are supported at the bottom of the crystal boat 217.

[0034] A temperature sensor 263, serving as a temperature detector, is installed inside the reaction tube 203. By adjusting the energization of the heater 207 based on the temperature information detected by the temperature sensor 263, the temperature within the processing chamber 201 is adjusted to achieve the desired temperature distribution. The temperature sensor 263 is disposed along the inner wall of the reaction tube 203.

[0035] like Figure 3 As shown, the controller 121, serving as the control unit (control unit), is configured as a computer equipped with a CPU (Central Processing Unit) 121a, RAM (Random Access Memory) 121b, a storage device 121c, and an I / O port 121d. The RAM 121b, storage device 121c, and I / O port 121d are configured 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. Additionally, an external storage device 123 can be connected to the controller 121. Furthermore, the processing device can be configured to have one control unit or multiple control units. That is, one control unit can be used to control the processing sequence described later, or multiple control units can be used to control the processing sequence described later. Furthermore, multiple control units can be configured as a control system interconnected via a wired or wireless communication network, or the entire control system can be used to control the processing sequence described later. The use of the term "control unit" in this specification includes not only cases with one control unit, but also cases with multiple control units and cases with a control system composed of multiple control units.

[0036] The storage device 121c is composed of, for example, flash memory, HDD (Hard Disk Drive), SSD (Solid State Drive), etc. The storage device 121c contains a control program that controls the operation of the processing device, and a process recipe that describes the steps or conditions of the substrate processing described later. The process recipe is a combination of each step in the substrate processing described later, executed by the processing device via the controller 121, in a manner that allows for a predetermined structure, and functions as a program. Hereinafter, the process recipe, control program, etc., will be collectively referred to as a program. Additionally, the process recipe may sometimes be simply referred to as a recipe. The term "program" is used in this specification in cases where only the recipe unit is included, cases where only the control program unit is included, and cases where both are included. RAM 121b is configured as a memory area for temporarily storing programs or data read by CPU 121a.

[0037] I / O port 121d is connected to the aforementioned MFC241a~241e, valves 243a~243e, pressure sensor 245, APC valve 244, vacuum pump 246, temperature sensor 263, heater 207, rotating mechanism 267, lifter 115, baffle opening and closing mechanism 115s, etc.

[0038] CPU 121a is configured to read and execute control programs from storage device 121c, and can also read recipes from storage device 121c based on inputs such as operation instructions from input / output device 122. CPU 121a is configured to control, according to the read recipe, the following actions: flow rate adjustment of various substances (various gases) by MFCs 241a-241e; opening and closing of valves 243a-243e; opening and closing of APC valve 244; pressure adjustment of APC valve 244 based on pressure sensor 245; start and stop of vacuum pump 246; temperature adjustment of heater 207 based on temperature sensor 263; rotation and speed adjustment of crystal boat 217 by rotating mechanism 267; lifting and lowering of crystal boat 217 by elevator 115; and opening and closing of baffle 219s by baffle opening and closing mechanism 115s.

[0039] The controller 121 is configured to install the aforementioned program, recorded and stored in the external storage device 123, onto a computer. The external storage device 123 includes, for example, a hard disk such as an HDD, an optical disk such as a CD, a USB flash drive, or a semiconductor memory such as an SSD. The storage device 121c or the external storage device 123 constitutes a computer-readable storage medium containing a program. Hereinafter, they will be collectively referred to as storage media. The term "storage media" is used in this specification in cases including only the storage device 121c, only the external storage device 123, and both. Furthermore, the program may be provided to the computer without using the external storage device 123, but instead using communication methods such as a network or dedicated line.

[0040] (2) Substrate processing steps

[0041] For example, in a process of manufacturing a semiconductor device, the above-mentioned processing apparatus (substrate processing apparatus) is used to etch the wafer 200, which serves as a substrate. The main process used is... Figure 4 , Figure 5 (a)~ Figure 5 (d) Explanation. In the following explanation, the operation of each part constituting the processing device is controlled by the controller 121.

[0042] As a wafer 200 processed by a substrate processing step according to one aspect of the present invention, a Si substrate made of single-crystal silicon (Si) can be used, for example. On the surface of the wafer 200, for example, a substrate is formed... Figure 5 (a) shows grooves or pores or other recesses on the surface where a natural oxide film 200a, such as a silicon oxide film (SiO film), is formed. Hereinafter, the natural oxide film 200a will sometimes be referred to simply as film 200a.

[0043] like Figure 4 As shown, the processing sequence of this scheme includes etching the film 200a by performing a cycle comprising the following steps a predetermined number of times (n times, where n is an integer of 1 or 2 or higher):

[0044] (a) Step A: supplying modified gas to membrane 200a;

[0045] (b) Step B, which involves supplying an inert gas to membrane 200a; and with

[0046] (c) Step C: Supplying etching gas to membrane 200a.

[0047] In the above loop, at least a portion of the implementation period of step A and the implementation period of step B overlap.

[0048] In addition, such as Figure 4As shown, in the processing sequence of this solution, step A begins before step B, and step B begins while step A is still being executed. This solution explains the scenario where step B is performed during the latter half of the implementation period of step A.

[0049] In addition, as an example, the following situation will be explained in this plan: After implementing step C, the process chamber 201 will be heated (hereinafter referred to as step D).

[0050] In this specification, for convenience, the above-described substrate processing sequence is sometimes indicated as follows. The same notation is also used in the following descriptions of variations or other solutions.

[0051] (Modified gas + Inert gas → Etching gas → Heating) × n

[0052] As used in this specification, the term "wafer" sometimes refers to the wafer itself, and sometimes to a laminate of the wafer and a predetermined layer or film formed on its surface. The term "wafer surface" sometimes refers to the surface of the wafer itself, and sometimes to the surface of a predetermined layer, etc., formed on the wafer. The phrase "etching a predetermined layer on the wafer" as described in this specification sometimes refers to directly etching a predetermined layer on the surface of the wafer itself, and sometimes refers to etching a predetermined layer formed on top of layers, etc., formed on the wafer. The term "substrate" as used in this specification has the same meaning as the term "wafer."

[0053] As used in this specification, the term "substance" includes at least one of gaseous and liquid substances. Liquid substances include mist-like substances. That is, a substance may include gaseous substances, liquid substances such as mist-like substances, or both.

[0054] (Filling and crystal boat loading)

[0055] When multiple wafers 200 are loaded into the crystal boat 217, the baffle 219s is moved by the baffle opening and closing mechanism 115s, opening the lower end of the manifold 209. Then, as... Figure 1 As shown, a wafer boat 217 supporting multiple wafers 200 is lifted by a wafer boat lifter 115 and moved into the processing chamber 201 (wafer boat loading). In this state, the cover 219 seals the lower end of the manifold 209 via an O-ring 220b. In this way, wafers 200 are prepared (provided) into the processing chamber 201.

[0056] (Pressure and temperature adjustment)

[0057] After the wafer boat is loaded, vacuum pump 246 is used to exhaust the vacuum (reduced pressure exhaust) to bring the processing chamber 201, i.e., the space containing the wafer 200, to the desired pressure (vacuum level). At this time, the pressure inside the processing chamber 201 is measured by pressure sensor 245, and APC valve 244 is controlled based on the measured pressure information. Additionally, heating is performed by heater 207 to bring the wafer 200 inside the processing chamber 201 to the desired processing temperature. The energization of heater 207 is controlled based on temperature information detected by temperature sensor 263 to achieve the desired temperature distribution inside the processing chamber 201. Furthermore, the wafer 200 is rotated by rotation mechanism 267. Exhausting the vacuum in the processing chamber 201, heating the wafer 200, and rotating the wafer 200 all continue at least until the processing of the wafer 200 is completed.

[0058] (Etching)

[0059] Then, perform the following steps A through D in that order.

[0060] [Step A]

[0061] In this step, a modified gas is supplied to the wafer 200 in the processing chamber 201, that is, the film 200a formed on the surface of the wafer 200.

[0062] Specifically, valve 243a is opened, allowing modified gas to flow into gas supply pipe 232a. The modified gas flow rate is adjusted by MFC 241a, supplied to processing chamber 201 via nozzle 249a, and discharged from exhaust port 231a. At this time, modified gas is supplied to wafer 200 from a direction different from the bottom direction of the recess on the surface of wafer 200 (modified gas supply). In this specification, the bottom direction of the recess refers to a direction perpendicular to the upper surface of the recess. A direction different from the bottom direction of the recess is, for example, a direction substantially perpendicular to the bottom direction of the recess. Furthermore, when the recess extends along the thickness direction of wafer 200, the direction different from the bottom direction of the recess is a direction substantially parallel to the surface of wafer 200. Additionally, when the recess extends along a direction substantially parallel to the surface of wafer 200, the direction different from the bottom direction of the recess is a direction perpendicular to the surface of wafer 200.

[0063] Examples of processing conditions for supplying the modified gas in this step are as follows:

[0064] Processing temperature: 20~75℃, preferably 25~70℃;

[0065] Processing pressure: 1–10000 Pa, preferably 10–1333 Pa;

[0066] Modified gas supply flow rate: 0.01–3 slm, preferably 0.1–1 slm;

[0067] Modified gas supply time: 30-1800 seconds, preferably 50-1200 seconds.

[0068] The processing pressure in this step is preferably higher than the processing pressure in step C described later. Furthermore, in this step, it is preferable to maintain the modified gas in its undecomposed state at the aforementioned processing pressure.

[0069] Furthermore, the notation of numerical ranges such as "20~75℃" in this specification means that the range includes both the lower and upper limits. Therefore, for example, "20~75℃" means "above 20℃ and below 75℃". Other numerical ranges follow the same principle. Additionally, the processing temperature in this specification 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; in other words, it refers to the pressure of the space in which the wafer 200 exists. Furthermore, the processing time refers to the duration of the processing. Additionally, the supply flow rate includes cases where 0 slm is supplied; 0 slm means that no substance (gas) is supplied. These same principles apply in the following descriptions.

[0070] By supplying a modifying gas to the wafer 200 (film 200a) under the above processing conditions, at least one of the following can be adsorbed onto the surface of film 200a: the modifying gas, a substance having a part of the molecular structure of the modifying gas, and a predetermined element contained in the modifying gas (see reference). Figure 5 (b)). Hereinafter, the term "modified gas" may refer to at least one of the following: a modified gas, a substance having part of the molecular structure of a modified gas, or a modified gas containing at least one predetermined element. Additionally, Figure 5 (b)~ Figure 5 In (d), the modified gas is indicated by the letter α.

[0071] By supplying a modified gas to the wafer 200 (film 200a) under the above processing conditions, the modified gas fills from the upper surface (hereinafter referred to as the upper surface of the recess) on the opening side of the recess formed on the wafer 200 to the bottom surface (hereinafter referred to as the bottom surface of the recess) on the inner side of the recess, causing the modified gas to be adsorbed on the upper surface of the recess, the inner side surface of the recess, and the bottom surface (hereinafter referred to as the side surface and bottom surface of the recess). At this time, the modified gas is preferentially adsorbed on the upper surface of the recess compared to the side surface and bottom surface of the recess. In other words, the amount of modified gas adsorbed on the upper surface of the recess is greater than the amount of modified gas adsorbed on the side surface and bottom surface of the recess (refer to...). Figure 5 (b)).

[0072] For example, NH-containing gases such as ammonia (NH3), hydrazine (N2H4), pyridine (C5H5N), pyrimidine (C4H4N2), and methylpyridine (C6H7N) can be used as modifying gases. One or more of these can be used as modifying gases.

[0073] [Step B]

[0074] After step A begins, and after a predetermined time has elapsed, while continuing to execute step A, an inert gas is supplied to the wafer 200 in the processing chamber 201, i.e., the membrane 200a adsorbed with the modified gas (refer to...). Figure 4 ).

[0075] Specifically, during the latter half of step A, after the modified gas is adsorbed on the upper, side, and bottom surfaces of the recess—that is, the entire surface of the recess—while continuing to supply modified gas, valves 243c-243e are opened to allow inert gas to flow into gas supply pipes 232c-232e. The inert gas flow rate is adjusted by MFCs 241c-241e, and it is supplied to the processing chamber 201 via nozzles 249a-249c and discharged from exhaust port 231a. At this time, inert gas is supplied to the wafer 200 from a direction different from the bottom direction of the recess (inert gas supply).

[0076] The following is an example of the processing conditions for supplying inert gas in this step:

[0077] Processing temperature: 20~75℃, preferably 25~70℃;

[0078] Processing pressure: 1–10000 Pa, preferably 10–1333 Pa;

[0079] Inert gas supply flow rate: 0.01–3 slm, preferably 0.1–1 slm;

[0080] Inert gas supply time: 10-300 seconds, preferably 20-60 seconds.

[0081] The execution time of this step (the inert gas supply time) is preferably shorter than the execution time of step A (the modified gas supply time). Furthermore, the amount of inert gas supplied in this step is preferably less than the amount of modified gas supplied in step A. Additionally, the gas supply amount can be obtained by multiplying the gas supply flow rate by the gas supply time.

[0082] By supplying an inert gas to the membrane 200a, which adsorbs modified gases, etc., from a direction different from, for example, the bottom direction of the recess, under the above conditions, a portion of the modified gases, etc., adsorbed (layered) on the upper surface of the recess can be peeled off from the upper surface of the recess and removed (detached) (see reference). Figure 5(c)). On the other hand, the supply of inert gas under the above conditions will not cause the modified gas adsorbed on the sides and bottom of the recess to peel off. Thus, by adjusting the amount of modified gas adsorbed on the surface of the recess, in this embodiment, the amount of modified gas adsorbed on the upper surface of the recess can be less than the amount of modified gas adsorbed on the sides and bottom of the recess (see reference). Figure 5 (c)). Furthermore... Figure 5 In (c), the flow of inert gas is shown by arrows.

[0083] As inert gases, rare gases such as nitrogen (N2), argon (Ar), helium (He), neon (Ne), and xenon (Xe) can be used. More than one of these can be used as an inert gas. This also applies to the steps described later.

[0084] Next, valves 243a and 243c-243e are closed to stop the supply of modified and inert gases to the processing chamber 201. Then, the processing chamber 201 is evacuated to remove any gaseous substances remaining in the processing chamber 201. Alternatively, valves 243c-243e can be kept open to supply inert gas to the processing chamber 201 through nozzles 249a-249c. The inert gas supplied from nozzles 249a-249c acts as a purging gas, thereby purging the space where the wafer 200 exists, i.e., the processing chamber 201.

[0085] [Step C]

[0086] After steps A and B are completed, etching gas is supplied to the wafer 200 in the processing chamber 201, i.e., the film 200a adsorbing modified gases, etc. (refer to...) Figure 4 ).

[0087] Specifically, valve 243b is opened to allow etching gas to flow into gas supply pipe 232b. The etching gas flow rate is adjusted by MFC 241b and supplied to processing chamber 201 via nozzle 249b, and discharged from exhaust port 231a. At this time, etching gas is supplied to wafer 200 (etching gas supply). Alternatively, valves 243c to 243e can be opened to supply inert gas into processing chamber 201 via nozzles 249a to 249c respectively.

[0088] Examples of processing conditions for supplying etching gas in this step are as follows:

[0089] Processing temperature: 25~75℃, preferably 25~70℃;

[0090] Processing pressure: 1–10000 Pa, preferably 10–1333 Pa;

[0091] Etching gas supply flow rate: 0.01~3 slm, preferably 0.1~1 slm;

[0092] Etching gas supply time: 10-120 seconds, preferably 20-60 seconds;

[0093] Inert gas supply flow rate (per gas supply pipe): 0-10 slm.

[0094] Under the above processing conditions, an etching gas is supplied to the wafer 200 (film 200a), which can adsorb at least one of the following: the etching gas, a substance having part of the molecular structure of the etching gas, and a predetermined element contained in the etching gas (see reference). Figure 5 (d)). Hereinafter, etching gas, a substance having part of the molecular structure of etching gas, or at least one of the predetermined elements contained in etching gas are sometimes referred to as etching gas, etc. Furthermore, in Figure 5 In (d), the word β is used to indicate etching gas, etc.

[0095] By supplying etching gas to the film 200a under the aforementioned processing conditions, the etching gas can be transported from the upper surface of the recess formed on the wafer 200 to the bottom surface of the recess, causing the etching gas to be adsorbed on the upper surface, side surface, and bottom surface of the recess. At this time, the etching gas is preferentially adsorbed on the upper surface of the recess compared to the side surface and bottom surface. In other words, the amount of etching gas adsorbed on the upper surface of the recess is greater than the amount adsorbed on the side surface and bottom surface of the recess (see reference). Figure 5 (d)).

[0096] For example, fluorine-containing (F) gases such as hydrogen fluoride (HF), chlorine trifluoride (ClF3), fluorine (F2), nitrogen trifluoride (NF3), and carbon tetrafluoride (CF4) can be used as etching gases. More than one of these gases can be used as etching gases.

[0097] After the etching gas and other modified gases are adsorbed onto the surface of the film 200a, valve 243d is closed to stop the supply of etching gas to the processing chamber 201. Then, the processing chamber 201 is evacuated to remove any gaseous substances remaining in the processing chamber 201. At this time, valves 243c to 243e are opened to supply inert gas to the processing chamber 201 through nozzles 249a to 249c. The inert gas supplied from nozzles 249a to 249c acts as a purging gas, thereby purging the space where the wafer 200 exists, i.e., the processing chamber 201.

[0098] [Step D]

[0099] The output of heater 207 is adjusted to raise the temperature inside processing chamber 201, i.e., the temperature of wafer 200, to a predetermined temperature. Additionally, vacuum pump 246 is used to vent a vacuum, bringing the space inside processing chamber 201, i.e., the space containing wafer 200, to a predetermined pressure. This step is preferably performed in an inert gas environment. That is, during this step, valves 243c-243e are preferably opened to supply inert gas into processing chamber 201 via nozzles 249a-249c, purging processing chamber 201.

[0100] As an example of a processing condition in this step:

[0101] Processing temperature: 100~200℃, preferably 150~200℃;

[0102] Processing pressure: 1–10000 Pa, preferably 10–1333 Pa;

[0103] Processing time: 0.5 to 5 hours

[0104] Inert gas supply flow rate (per gas supply pipe): 0-10 slm.

[0105] By heating the wafer 200 under the above-described processing conditions (heat treatment), the film 200a can be etched. The following example illustrates the etching process of film 200a, where the film 200a formed on the surface of the recess is a SiO film, and NH3 gas is used as the modifying gas and HF gas as the etching gas. Under the above-described processing conditions, steps A and C are performed. When NH3 gas (modifying gas) and HF gas (etching gas) are supplied to the SiO film (film 200a), the NH3 gas and HF gas are adsorbed onto the surface of the wafer 200 and react with the SiO film. The SiO film after reacting with the NH3 gas and HF gas is modified into an ammonium hexafluorosilicate ((NH4)SiF6) film. Then, under the above-described processing conditions, step D is performed to heat the wafer 200, thereby causing the (NH4)SiF6 film to sublimate and be removed (etched).

[0106] After etching the film 200a, a vacuum is applied to the processing chamber 201 to remove any remaining gaseous substances. At this time, valves 243c-243e are opened, supplying inert gas into the processing chamber 201 through nozzles 249a-249c. The inert gas supplied from nozzles 249a-249c acts as a purging gas, thereby purging the space containing the wafer 200, i.e., the processing chamber 201. Then, as needed, the temperature inside the processing chamber 201 is lowered to the processing temperature of step A.

[0107] [Number of scheduled implementations]

[0108] By performing steps A through D in this order n times (n being an integer of 1 or 2), the film 200a formed on the surface of wafer 200 can be etched to a predetermined depth. Preferably, the above-described cycle is repeated multiple times. That is, preferably, the thickness of the film etched in each cycle is thinner than the desired thickness, and the above-described cycle is repeated multiple times until the thickness of the film removed by etching becomes the desired thickness.

[0109] (Purge and atmospheric pressure recovery)

[0110] After the etching process is completed, inert gases are supplied as purging gases into the processing chamber 201 through nozzles 249a to 249c, and exhaust gases are discharged through exhaust port 231a. This purges the processing chamber 201, removing residual ambient gases or reaction byproducts. Afterward, the ambient gases in the processing chamber 201 are replaced with inert gases, and the pressure inside the processing chamber 201 returns to atmospheric pressure.

[0111] (Wafer removal and wafer take-out)

[0112] Next, the cover 219 is lowered by the lifter 115, opening the lower end of the manifold 209. Then, the processed wafer 200, supported by the crystal boat 217, is moved from the lower end of the manifold 209 to the outside of the reaction tube 203. After being moved out, the baffle 219s moves, sealing the lower opening of the manifold 209 by the baffle 219s via the O-ring 220c. After being moved to the outside of the reaction tube 203, the processed wafer 200 is removed from the crystal boat 217.

[0113] (3) Effects of this implementation method

[0114] According to this embodiment, one or more of the effects shown below can be obtained.

[0115] (a) By overlapping at least a portion of the execution period of step A and the execution period of step B, the amount of modified gas, etc., adsorbed on the surface of film 200a can be adjusted. This allows for adjustment (control) of the etching amount of film 200a. Especially when a recess is formed on the surface of wafer 200, the amount of modified gas present on the upper surface of the recess can be made different from the amount of modified gas present on the side and bottom surfaces of the recess. In other words, the amount of modified gas present on the opening side of the recess can be made different from the amount of modified gas present on the bottom side of the recess. This allows for adjustment (control) of the etching amount of film 200a formed on the upper surface of the recess and film 200a formed on the side and bottom surfaces of the recess. These will be explained below. Furthermore, the amount of modified gas present is the amount of molecules or a portion of molecules of the material constituting the modified gas itself. Additionally, the modified gas also includes substances floating in the space within the recess or substances adsorbed on the surfaces within the recess.

[0116] For example, when supplying gas to a wafer 200 with recesses on its surface, the supplied gas tends to preferentially adsorb onto the upper surface of the recesses. That is, the amount of modified gas or etching gas adsorbed onto the upper surface of the recesses is greater than the amount adsorbed onto the sides and bottom of the recesses. Therefore, when etching the film 200a formed on the surface of the recesses, the upper surface of the recesses will be etched more than the sides and bottom of the recesses, making it difficult to etch the film 200a uniformly.

[0117] In this scheme, the execution period of step A and a portion of the execution period of step B overlap. Specifically, while the membrane 200a is supplied with a modified gas in step A, an inert gas is supplied to the membrane 200a in step B. This allows a portion of the modified gas, etc., adsorbed on the upper surface of the recess to be removed (detached) by the flow of the inert gas (see reference). Figure 5 (c) This reduces the amount of modified gas, etc., adsorbed (present) on the upper surface of the recess. Then, when etching gas is supplied to the film 200a in step C, although the etching gas preferentially adsorbs on the upper surface of the recess, the amount of modified gas, etc., adsorbed on the upper surface of the recess is small, thus suppressing the etching amount of the film 200a on the upper surface of the recess. On the other hand, the modified gas, etc., adsorbed (present) on the side and bottom surfaces of the recess is almost unaffected by the inert gas supplied in step B. Therefore, the amount of modified gas, etc., present on the side and bottom surfaces of the recess hardly decreases. Thus, in step C, the film 200a formed on the side and bottom surfaces of the recess is etched almost unaffected by the inert gas supplied in step B. In this way, the etching amount of the film 200a on the upper surface and the side and bottom surfaces of the recess can be adjusted (controlled). As a result, the film 200a can be etched uniformly.

[0118] (b) By making the pressure in the processing chamber 201 in step A higher than the pressure in the processing chamber 201 in step C, that is, by performing step A at a higher pressure, the interior of the recess can be filled with modified gas, and the modified gas can be uniformly adsorbed from the opening of the recess to the bottom surface.

[0119] (c) By performing step B during the latter half of the implementation period of step A, the amount of modified gas, etc., present on the upper surface of the recess can be reduced compared to the amount of modified gas, etc., present on the sides and bottom of the recess. Specifically, by performing step B during the latter half of the implementation period of step A, after the modified gas has filled the space from the upper surface to the bottom of the recess, an inert gas is supplied. The inert gas is preferentially supplied to the upper surface of the recess, thus removing (detaching) the modified gas, etc., present on the upper surface of the recess. In contrast, the modified gas, etc., present on the sides and bottom of the recess is almost unaffected by the inert gas, thus maintaining its state of remaining inside the recess. Therefore, the amount of modified gas, etc., present on the upper surface of the recess can be reduced compared to the amount of modified gas, etc., present on the sides and bottom of the recess.

[0120] (d) By shortening the execution time of step B compared to the execution time of step A, the controllability of the amount of modified gas, etc., adsorbed on membrane 200a (residual on membrane 200a) can be improved. Specifically, by shortening the execution time of step B, inert gas can be supplied only momentarily for a short time, thus reducing the amount of modified gas, etc., present on the upper surface of the recess without significantly reducing the amount of modified gas, etc., present on the side and bottom surfaces of the recess.

[0121] (e) By making the amount of inert gas supplied in step B less than the amount of modified gas supplied in step A, the controllability of the amount of modified gas and the like adsorbed on membrane 200a can be improved.

[0122] (4) Variations

[0123] The processing sequence of this scheme can be changed as shown in the following variations. These variations can be combined arbitrarily. Unless otherwise specified, the processing procedures and conditions in each step of each variation can be the same as those in each step of the above processing sequence.

[0124] (Variation Example 1)

[0125] Step B can also be performed during the middle period (i.e., the middle or mid-term) of the implementation of step A. In this variation, the same effect as the above scheme can be obtained.

[0126] (Variation Example 2)

[0127] Alternatively, steps A through D can be performed in the order of steps B, A, C, and D, while inert gas is continuously supplied in step B, and step A, which supplies the modified gas, can then begin. Specifically, step A can also be performed during the latter half of the implementation period of step B.

[0128] In this modified example, at least some of the effects described in the above-described scheme can also be obtained. Furthermore, in this modified example, by performing step A in the latter half of the execution period of step B, the amount of modified gas, etc., present on the upper surface of the recess can be greater than the amount of modified gas, etc., present on the sides and bottom of the recess. The reason for this is that since step A is performed in the latter half of the execution period of step B, the modified gas is supplied after the interior of the recess has been filled with inert gas. Because the interior of the recess is filled with inert gas, the modified gas is preferentially supplied to the upper surface of the recess, thereby causing most of the supplied modified gas to be adsorbed onto the upper surface of the recess. In this way, the amount of modified gas, etc., present on the upper surface of the recess can be greater than the amount of modified gas, etc., present on the sides and bottom of the recess. As a result, the film 200a formed on the upper surface of the recess can be etched more effectively. This modified example is particularly useful when it is desired to widen the opening of the recess.

[0129] (Variation Example 3)

[0130] Alternatively, steps A through D can be performed in the order of steps B, A, C, and D, while step A, which supplies the modified gas, is started while step B is continuously supplied with inert gas. Specifically, step A can also be performed in the middle of the implementation period of step B (i.e., the middle or intermediate stage).

[0131] In this modified example, at least some of the effects described in the above-described solution can also be obtained. Furthermore, in this modified example, by performing step A during a mid-period of the implementation of step B, the amount of modified gas, etc., present on the upper surface of the recess can be greater than the amount of modified gas, etc., present on the sides and bottom of the recess. The reason for this is that by performing step A during a mid-period of the implementation of step B, the modified gas is supplied after the interior of the recess has been filled to a certain extent with inert gas. Since the interior of the recess is filled to a certain extent with inert gas, the modified gas is preferentially supplied to the upper surface of the recess, thereby most of the supplied modified gas is adsorbed onto the upper surface of the recess. In this way, the amount of modified gas, etc., present on the upper surface of the recess can be greater than the amount of modified gas, etc., present on the sides and bottom of the recess. As a result, the film 200a formed on the upper surface of the recess can be etched selectively. This modified example is useful when it is desired to widen the opening of the recess.

[0132] (Variation Example 4)

[0133] Alternatively, as shown in the following processing sequence, step E can also include supplying an inert gas to the membrane 200a during the implementation of step C. Specifically, step E can begin while the etching gas is being continuously supplied in step C, and the inert gas can be supplied at the same time. Step E can be performed during the latter half of the implementation period of step C, or it can be performed during the middle (mid-stage) of the implementation period of step C. In this modified example, the implementation time of step E is preferably shorter than the implementation time of step C. In addition, the amount of inert gas supplied in step E is less than the amount of etching gas supplied in step C.

[0134] (Modified gas + inert gas → Etching gas + inert gas → Heating treatment) × n

[0135] In this modified example, the same effect as the above-described solution can be obtained. In this modified example, by further performing step E, the flow of etching gas present on the film 200a can be improved, thus enhancing the controllability of the amount of etching gas remaining on the film 200a. By performing step E during the latter half or middle of the execution period of step C, the controllability of the amount of etching gas, etc., present on the upper surface of the recess can be improved in particular. By making the execution time of step E shorter than that of step C, and by making the supply amount of inert gas in step E less than that of etching gas in step C, the controllability of the amount of etching gas, etc., present on the upper surface of the recess can be improved in particular.

[0136] <Other aspects of the present invention>

[0137] The present invention has been specifically described above. However, the present invention is not limited to the above-described solution, and various modifications can be made without departing from its spirit.

[0138] For example, the above-described embodiment illustrates the case where the film 200a, which is the object of etching, is formed on the surface of the wafer 200. However, the present invention is not limited to this embodiment. For example, the film 200a, which is the object of etching, may also be formed on the reaction tube 203, etc. In this embodiment, the same effects as the above-described embodiment can be obtained.

[0139] For example, the above-described solution uses a wafer 200 with recesses formed on its surface as an example. However, the present invention is not limited to this solution. For example, a wafer 200 without recesses formed on its surface can also be used. In this solution, the same effects as the above-described solution can be obtained.

[0140] Although not specifically mentioned in the above scheme, inert gas can also be pulsed in step B or step E. The same effect as the above scheme can be achieved in this scheme. In this scheme, the controllability of the amount of modified gas or etching gas remaining on the membrane 200a can be further improved.

[0141] For example, the above description illustrates the case where a SiO film is formed on the concave surface. However, the present invention is not limited to this approach. For example, a silicon nitride film (SiN film) may also be formed. Furthermore, a film containing a metal element may also be formed. The metal-containing film may be a film containing a single metal element, or a film containing a metal element and at least one of oxygen, nitrogen, and carbon. In this embodiment, the same effects as described above can be obtained.

[0142] The formulations used in each process are preferably prepared individually according to the processing requirements and recorded and stored in the storage device 121c via a telecommunication channel or external storage device 123. Then, preferably, when starting each process, the CPU 121a selects a suitable formulation from the multiple formulations recorded and stored in the storage device 121c according to the processing requirements. As a result, the processing device can perform etching with good reproducibility for various film types, composition ratios, film qualities, and film thicknesses. In addition, it can reduce the operator's workload and allow each process to start quickly while avoiding operational errors.

[0143] The above-described formula is not limited to newly created formulations; for example, it can also be prepared by modifying an existing formula already installed in the processing device. In the case of a modified formula, the modified formula can be installed in the processing device via a telecommunication channel or a storage medium containing the formula. Alternatively, the existing formula already installed in the processing device can be directly modified by operating the input / output device 122 of the existing processing device.

[0144] In the above-described embodiments, an example of etching the film using a batch processing apparatus that processes multiple substrates at a time has been explained. The present invention is not limited to the above embodiments; for example, it can also be suitably applied to etching the film using a single-piece processing apparatus that processes one or more substrates at a time. Furthermore, in the above-described embodiments, an example of etching the film using a processing apparatus with a hot-wall type furnace has been explained. The present invention is not limited to the above embodiments; it can also be suitably applied to etching the film using a processing apparatus with a cold-wall type furnace.

[0145] Furthermore, the above-described solution illustrates an example of performing the aforementioned processing sequence within the same processing chamber (in-situ) of the same processing device. The present invention is not limited to the above-described solution; for example, any step in the above-described processing sequence and other steps may be performed separately in different processing chambers (ex-situ) of different processing devices, or separately in different processing chambers of the same processing device.

[0146] When using these processing devices, each process can be performed according to the same processing procedure and processing conditions as the above-described scheme or modification, and the same effect as the above-described scheme or modification can be obtained.

[0147] The above-described solutions or variations can be appropriately combined and used. The processing procedures and conditions in this case can be the same as those in the above-described solutions or variations.

[0148] Symbol Explanation

[0149] 200a—membrane.

Claims

1. A processing method, characterized in that, The process involves etching a film by overlapping at least a portion of the implementation period of (a) and the implementation period of (b) a predetermined number of times in a cycle comprising (a), (b), and (c). The above (a) refers to the process of supplying the modified gas to the above membrane. The above (b) describes the process of supplying inert gas to the membrane. The above (c) is the process of supplying etching gas to the above membrane.

2. The processing method according to claim 1, characterized in that, The implementation time of (b) is shorter than that of (a).

3. The processing method according to claim 1, characterized in that, In (b), the inert gas is pulsed and supplied.

4. The processing method according to claim 1, characterized in that, (b) will be carried out during the latter half of the implementation period of (a).

5. The processing method according to claim 1, characterized in that, (b) will be carried out during the middle period of the implementation of (a).

6. The processing method according to claim 1, characterized in that, The supply of the inert gas in (b) is less than the supply of the modified gas in (a).

7. The processing method according to claim 1, characterized in that, (a) will be carried out during the latter half of the implementation period of (b).

8. The processing method according to claim 1, characterized in that, (a) will be carried out during the middle period of the implementation of (b).

9. The processing method according to claim 1, characterized in that, It has (e), which is the process of supplying the inert gas to the membrane during the implementation of (c).

10. The processing method according to claim 9, characterized in that, The implementation time of (e) is shorter than that of (c).

11. The processing method according to claim 9, characterized in that, In (e), the inert gas is pulsed and supplied.

12. The processing method according to claim 9, characterized in that, (e) will be carried out during the latter half of the implementation period of (c).

13. The processing method according to claim 9, characterized in that, (e) will be carried out during the middle period of the implementation of (c).

14. The processing method according to claim 13, characterized in that, The supply of the inert gas in (e) is less than the supply of the etching gas in (c).

15. The processing method according to any one of claims 1 to 14, characterized in that, A recess is provided on the surface of the substrate on which the above-mentioned film is formed.

16. The processing method according to claim 15, characterized in that, The modified gas and the inert gas are supplied from a direction different from the bottom direction of the recess.

17. The processing method according to claim 15, characterized in that, The pressure in the space where the substrate exists in (a) is higher than the pressure in the space where the substrate exists in (c).

18. A method for manufacturing a semiconductor device, characterized in that, The process involves etching a film by overlapping at least a portion of the implementation period of (a) and the implementation period of (b) a predetermined number of times in a cycle comprising (a), (b), and (c). The above (a) refers to the process of supplying the modified gas to the above membrane. The above (b) describes the process of supplying inert gas to the membrane. The above (c) is the process of supplying etching gas to the above membrane.

19. A program, characterized in that, The processing device is instructed by a computer to perform the following steps: etching the film by overlapping at least a portion of the implementation period of (a) and the implementation period of (b) a predetermined number of times in a cycle comprising (a), (b), and (c). The above (a) refers to the step of supplying the modified gas to the above membrane. The above (b) refers to the step of supplying an inert gas to the membrane. The above (c) is the step of supplying etching gas to the above membrane.

20. A processing apparatus, characterized in that, have: A first gas supply system for supplying modified gas to the membrane; A second gas supply system for supplying inert gas to the aforementioned membrane; A third gas supply system for supplying etching gas to the aforementioned membrane; and Control Department The control unit is configured to control the first gas supply system, the second gas supply system, and the third gas supply system to perform the following process: etching the film by overlapping at least a portion of the implementation period of (a) and the implementation period of (b) a predetermined number of times through a cycle including (a), (b), and (c). The above (a) describes the treatment of supplying the modified gas to the above membrane. The above (b) describes the process of supplying the above-mentioned inert gas to the above-mentioned membrane. The above (c) is the process of supplying the above etching gas to the above membrane.

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