Substrate processing method, substrate processing apparatus, and cleaning apparatus

Abstract

A substrate processing method includes: a step of preparing a substrate including an etching target film and a mask; a step of etching the etching target film through the mask with plasma; and a step of heat-treating the substrate at a predetermined temperature after the etching step. According to the present invention, the etching target film can be prevented from being damaged by a reaction product deposited on the etching target film.

Description

Technical Field

[0001] This invention relates to a substrate processing method, a substrate processing apparatus, and a cleaning apparatus. Background Technology

[0002] A method for etching high aspect ratio holes at low temperature on a semiconductor wafer composed of stacked silicon oxide and silicon nitride films is known (e.g., see Patent Document 1). When etching the silicon nitride-containing film using hydrogen-containing gas, reaction products are generated that deposit on the surface and / or sidewalls of the film after the etching process.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent document 1: Japanese Patent Application Publication No. 2016-207840. Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] The purpose of this invention is to prevent damage to the etched film caused by reaction products deposited on it.

[0008] Technical means for solving problems

[0009] According to one aspect of the present invention, a substrate processing method is provided, comprising: a step of preparing a substrate containing an etch target film and a mask; a step of etching the etch target film by passing plasma through the mask; and a step of heat-treating the substrate at a predetermined temperature after the etching step.

[0010] Invention Effects

[0011] According to one side, it can prevent the etched film from being damaged by reaction products deposited on the etched film. Attached Figure Description

[0012] Figure 1 This is a diagram illustrating an example of a substrate processing system according to one embodiment.

[0013] Figure 2 This is a diagram showing an example of an etched object film exposed to the atmosphere after the etching step.

[0014] Figure 3 This is a diagram illustrating an example of a substrate processing apparatus according to one embodiment.

[0015] Figure 4 This is a graph showing the analytical results of the reaction products generated during the etching step.

[0016] Figure 5 This is a flowchart illustrating an example of a substrate processing method according to one embodiment.

[0017] Figure 6 This is a diagram illustrating an example of the temperature at which various materials are modified or deformed.

[0018] Figure 7 This is a diagram illustrating an example of an etched object film after a heat treatment step in one embodiment.

[0019] Figure 8 This is a diagram showing an example of reaction products deposited on an inclined portion of a substrate according to one embodiment.

[0020] Figure 9 This is a diagram illustrating an example of a cleaning device according to one embodiment.

[0021] Explanation of reference numerals in the attached figures

[0022] 1: Substrate processing device

[0023] 2: Cleaning equipment,

[0024] 10: Substrate processing system

[0025] 11-14: Processing room,

[0026] 20: Vacuum transport chamber

[0027] 21: Conveying mechanism,

[0028] 31, 32: Load locking chamber,

[0029] 40: Atmospheric transport chamber

[0030] 41: Conveying mechanism,

[0031] 51-53: Loading ports

[0032] 61-68: Gate valves

[0033] 70: Control Department

[0034] 102: Handling containers,

[0035] 110: Silicon nitride film,

[0036] 120: Silicon oxide film,

[0037] 121: Stage (lower electrode),

[0038] 122: Upper electrode,

[0039] 170: Control Department

[0040] 300: Handling container,

[0041] 301: Platform,

[0042] 302: Upper electrode,

[0043] 310: Upper gas supply unit,

[0044] 320: Lower gas supply section,

[0045] 330: Gas Supply Department. Detailed Implementation

[0046] Hereinafter, with reference to the accompanying drawings, the embodiments for carrying out the present invention will be described. In the drawings, the same reference numerals are used to label the same components, and sometimes repeated descriptions are omitted.

[0047] [Substrate Processing System]

[0048] First, refer to Figure 1 An example of a substrate processing system 10 according to one embodiment will be described. Figure 1 This is a diagram illustrating an example of a substrate processing system 10 according to one embodiment. In the substrate processing system 10, a substrate processing method including an etching step and a heat treatment step according to one embodiment is performed.

[0049] The substrate processing system 10 includes processing chambers 11-14, vacuum transport chamber 20, load locking chambers 31 and 32, atmospheric transport chamber 40, load ports 51-53, gate valves 61-68, and control device 70.

[0050] Processing chamber 11 has a mounting stage 11a capable of holding a substrate W, and is connected to vacuum delivery chamber 20 via gate valve 61. Similarly, processing chamber 12 has a mounting stage 12a capable of holding a substrate, and is connected to vacuum delivery chamber 20 via gate valve 62. Processing chamber 13 has a mounting stage 13a capable of holding a substrate, and is connected to vacuum delivery chamber 20 via gate valve 63. Processing chamber 14 has a mounting stage 14a capable of holding a substrate, and is connected to vacuum delivery chamber 20 via gate valve 64. The processing chambers 11-14 can be depressurized to a predetermined vacuum atmosphere, and the substrate can be subjected to desired processing (etching, heat treatment, etc.) within them. Furthermore, the operation of each processing component in processing chambers 11-14 is controlled by control device 70.

[0051] The vacuum transport chamber 20 can be depressurized to a specified vacuum atmosphere. Furthermore, a transport mechanism 21 is provided within the vacuum transport chamber 20. The transport mechanism 21 transports substrates to processing chambers 11-14 and load locking chambers 31 and 32. The operation of the transport mechanism 21 is controlled by a control device 70.

[0052] The load locking chamber 31 has a mounting stage 31a capable of holding a substrate, connected to the vacuum delivery chamber 20 via a gate valve 65, and connected to the atmospheric delivery chamber 40 via a gate valve 67. Similarly, the load locking chamber 32 has a mounting stage 32a capable of holding a substrate, connected to the vacuum delivery chamber 20 via a gate valve 66, and connected to the atmospheric delivery chamber 40 via a gate valve 68. The load locking chambers 31 and 32 are configured to switch between atmospheric and vacuum atmospheres. Furthermore, the switching between vacuum and atmospheric atmospheres within the load locking chambers 31 and 32 is controlled by a control device 70.

[0053] An atmospheric atmosphere is formed within the atmospheric transport chamber 40, for example, a downward flow of clean air is formed. Furthermore, a transport mechanism 41 is provided within the atmospheric transport chamber 40. The transport mechanism 41 transports the substrate to the carrier C in the load locking chambers 31, 32, and the loading ports 51-53 (described later). Furthermore, the operation of the transport mechanism 41 is controlled by a control device 70.

[0054] Loading ports 51-53 are located on the long side wall of the atmospheric transport chamber 40. Loading ports 51-53 can accommodate a carrier C containing a substrate or an empty carrier C. For example, a FOUP (Front Opening Unified Pod) can be used as the carrier C.

[0055] Gate valves 61 to 68 are configured to open and close. Furthermore, the opening and closing of gate valves 61 to 68 are controlled by control device 70.

[0056] The control device 70 controls the entire substrate processing system 10 by performing actions on the processing chambers 11-14, the conveying mechanisms 21 and 41, the opening and closing of the gate valves 61-68, and the switching of the vacuum atmosphere or atmospheric atmosphere in the load locking chambers 31 and 32.

[0057] The following describes an example of the operation of the substrate processing system 10. For example, the control device 70 opens the gate valve 67 and controls the conveying mechanism 41 to convey the substrate, for example, housed in the carrier C in the loading port 51, to the loading stage 31a of the load locking chamber 31. The control device 70 closes the gate valve 67, creating a vacuum atmosphere inside the load locking chamber 31.

[0058] The control device 70 opens gate valves 61 and 65 and controls the conveying mechanism 21 to transport the substrate from the load locking chamber 31 to the mounting stage 11a of the processing chamber 11. The control device 70 closes gate valves 61 and 65, causing the processing chamber 11 to operate. As a result, a prescribed process (e.g., etching process) is performed on the substrate in the processing chamber 11.

[0059] Next, the control device 70 opens gate valves 61 and 63 and controls the conveying mechanism 21 to transport the substrate processed in processing chamber 11 to the mounting stage 13a in processing chamber 13. The control device 70 closes gate valves 61 and 63, causing processing chamber 13 to operate. As a result, the substrate undergoes a prescribed treatment (e.g., heat treatment, described later) in processing chamber 13.

[0060] The control device 70 can also transport the processed substrate in processing chamber 11 to a stage 14a capable of performing the same processing as processing chamber 13 in processing chamber 14. In this embodiment, the substrate in processing chamber 11 is transported to processing chamber 13 or processing chamber 14 depending on the operating state of processing chambers 13 and 14. Therefore, the control device 70 can use processing chambers 13 and 14 to perform a predetermined process (e.g., heat treatment) on multiple substrates simultaneously. This improves productivity. Similarly, processing chambers 11 and 12 can be used to perform etching on multiple substrates simultaneously, and processing chambers 12, 13, and 14 can be used to perform heat treatment on multiple substrates simultaneously.

[0061] Control device 70 controls conveying mechanism 21 to transport the processed substrate from processing chamber 13 or processing chamber 14 to the loading stage 31a of load locking chamber 31 or the loading stage 32a of load locking chamber 32. Control device 70 creates an atmospheric atmosphere within load locking chamber 31 or load locking chamber 32. Control device 70 opens gate valve 67 or gate valve 68 and controls conveying mechanism 41 to transport the substrate from load locking chamber 32 to carrier C, for example, loading port 53, and house it therein.

[0062] In this way, according to Figure 1 The substrate processing system 10 shown can perform etching and heat treatment on the substrate without exposing it to the atmosphere, i.e. without disrupting the vacuum atmosphere, during the processing of the substrate by each processing chamber.

[0063] Damage caused by atmospheric exposure

[0064] Figure 2 This is a diagram showing an example of an etched object film exposed to the atmosphere after the etching step. Figure 2 The film to be etched is a laminated film consisting of a silicon nitride (SiN) film 110 and a silicon oxide (SiO2) film 120. In the etching step, plasma of CF-based gas is used to etch the laminated film through a mask 130, thereby forming slots and holes in the laminated film.

[0065] When using plasmas containing CF-based or CHF-based gases to etch the laminated silicon nitride film 110 and silicon oxide film 120, ammonium fluoride silicide (AFS) is generated during etching and deposited on the laminated film. When the substrate is exposed to the atmosphere while AFS is deposited, the reaction products react with moisture in the atmosphere. The longer the exposure time, the more likely it is that depressions (side etching) 110b will form on the side of the silicon nitride film 110, or that expansion impurities 110a, which expand due to the reaction with moisture, will form on the sidewalls of the silicon nitride film 110. As a result, damage to the laminated film or blockage of gaps will have a negative impact on subsequent steps, leading to a decrease in yield. Furthermore, in order to minimize this yield reduction and complete the etching process, the atmospheric exposure time needs to be managed to shorten the period until the next substrate processing step.

[0066] Therefore, it is important to remove ammonium fluoride silicon before exposing the substrate to the atmosphere. To remove ammonium fluoride silicon, wet cleaning using pure water and chemical solutions can be employed. However, wet cleaning requires exposing the substrate to the atmosphere. Therefore, wet cleaning can cause side etching and expansion impurities on the substrate, potentially damaging the silicon nitride film 110. Furthermore, this additional step of wet cleaning can lead to a reduction in productivity.

[0067] In this embodiment, the substrate processing system 10 allows for heat treatment (baking, heating) after the etching step without exposing the substrate W to the atmosphere. This removes ammonium fluoride and prevents damage to the laminated film. Furthermore, in this embodiment, the substrate processing system 10 performs heat treatment before transporting the etched substrate to the atmospheric transport chamber 40 after etching, allowing for heat treatment without exposing the substrate to the atmosphere after etching. Therefore, after etching, it is not necessary to manage the atmospheric exposure time, such as the time required until the substrate returns to the FOUP and the time until the next substrate processing step, in a manner that prevents side etching and expansion impurities, making control easier.

[0068] Furthermore, etching and heat treatment are not limited to being performed in-system within the substrate processing system 10; they can also be performed in… Figure 3 In the substrate processing apparatus 1 of this embodiment, etching and heat treatment are performed in-situ. This allows for heat treatment to be performed after the etching step, without exposing the substrate to the atmosphere, and before the etched substrate is transported to the atmosphere transport chamber 40. This removes ammonium fluoride silicon, preventing a decrease in yield.

[0069] Furthermore, in the heat treatment chamber, a heater is provided in the stage to bring the stage to a high temperature for heat treatment of the substrate. Heat treatment can also be performed in at least one of a treatment chamber equipped with a stage having a heater or a load-locking chamber. Heat treatment can also be performed in a vacuum transport chamber 20 where a heater is mounted on the arm holding the substrate in the transport mechanism 21. Alternatively, the substrate W can be heat-treated by radiant heat from an irradiator or infrared heating.

[0070] [Substrate Processing Device]

[0071] Next, use Figure 3 The substrate processing apparatus 1 of one embodiment will be described. Figure 3 This is a diagram illustrating an example of a substrate processing apparatus 1 according to one embodiment. Here, as an example of the substrate processing apparatus 1, a capacitively coupled plasma etching apparatus can be cited. The substrate processing apparatus 1 corresponds to at least one of the processing chambers 11 to 14 of the substrate processing system 10 that can perform etching or heat treatment.

[0072] The substrate processing apparatus 1 includes, for example, a processing container 102 formed of a conductive material such as aluminum and a gas supply source 111 for supplying gas to the interior of the processing container 102. The processing container 102 is electrically grounded. Inside the processing container 102 is a mounting stage 121 and an upper electrode 122 arranged opposite and parallel to it. The mounting stage 121 also functions as a mounting stage for mounting the substrate W.

[0073] The stage 121 is connected to the first high-frequency power supply 132 via a first matching device 133, and to the second high-frequency power supply 134 via a second matching device 135. The first high-frequency power supply 132 applies high-frequency electrical power HF for plasma generation, for example, at a frequency of 27 MHz to 100 MHz, to the stage 121. The second high-frequency power supply 134 has a lower frequency than the first high-frequency power supply 132 and applies high-frequency electrical power LF for ion introduction, for example, at a frequency of 400 kHz to 13 MHz, to the stage 121. Furthermore, the first high-frequency power supply 132 can also be connected to the upper electrode 122 via the first matching device 133.

[0074] The first matching unit 133 matches the internal impedance of the first high-frequency power supply 132 with the load impedance. The second matching unit 135 matches the internal impedance of the second high-frequency power supply 134 with the load impedance. This allows the internal impedances of the first high-frequency power supply 132 and the second high-frequency power supply 134 to appear to match the load impedance during plasma generation in the processing space U.

[0075] The upper electrode 122 is mounted on top of the processing container 102 via an insulating component 141 covering its periphery. The upper electrode 122 is provided with a gas inlet 145 for introducing gas from the gas supply source 111 and a diffusion chamber 150 for diffusing the introduced gas. Gas output from the gas supply source 111 is supplied to the diffusion chamber 150 via the gas inlet 145, and then supplied to the processing space U through the orifice 128 via the gas flow path 155. As described above, the upper electrode 122 also functions as a gas spray head.

[0076] An exhaust port 160 is formed on the bottom surface of the processing container 102. An exhaust device 165 connected to the exhaust port 160 is used to exhaust air from the interior of the processing container 102. This allows the interior of the processing container 102 to be maintained at a predetermined vacuum level. A gate valve G is provided on the side wall of the processing container 102. The gate valve G opens and closes the inlet and outlet ports when the substrate W is fed into and out of the processing container 102.

[0077] The substrate processing apparatus 1 includes a control unit 170 that controls the overall operation of the apparatus. The control unit 170 includes a CPU, ROM, and RAM. The ROM stores basic programs executed by the control unit 170. The RAM stores a scheme. The scheme contains control information for the substrate processing apparatus 1 corresponding to processing conditions (etching conditions and heat treatment conditions). The control information includes processing time, pressure (gas exhaust), high-frequency electrical power or voltage, various gas flow rates, and chamber temperature (e.g., the set temperature of the substrate). Alternatively, the scheme can be stored on a hard disk or semiconductor memory. Furthermore, the scheme can be stored on a portable computer-readable storage medium such as a CD-ROM or DVD and set to a predetermined location in the storage area. The control unit 170 controls the substrate W to undergo desired processing, such as etching, by supplying a specified type of gas according to the scheme stored in the RAM, etc.

[0078] [Analysis of reaction products]

[0079] Figure 4 This graph shows the analytical results of the reaction products deposited on the sidewalls of the gaps formed in the silicon nitride film during the etching step. In this experiment, after etching the silicon nitride film formed on the substrate using CF4 and H2 gases in substrate processing apparatus 1, the substrate was placed in the atmosphere for 24 hours. Subsequently, the reaction products on the sidewalls of the silicon nitride film were analyzed using TOF (Time of Flight)-SIMS (Secondary Ion Mass Analysis).

[0080] Figure 4In the figure, (a) represents the mass spectrum (intensity) of the negative ions released during the secondary ionization of the sidewalls of the silicon nitride film after primary ion irradiation. The analysis confirms that the reaction products deposited on the sidewalls of the silicon nitride film by etching contain... Figure 4 Ammonium fluoride (NH4)(SiF5) is shown in (b) above. y﹣ In addition, such as Figure 4 As shown in (a), when the substrate temperature is controlled at -37°C and 25°C during etching of the silicon nitride film, more ammonium fluoride is removed in the case of etching the substrate at a low temperature of -37°C.

[0081] In other words, it is known that when using plasma containing hydrogen and fluorine gases to etch silicon nitride films, reaction products containing ammonium fluoride silicon are deposited on the surface and sidewalls of the silicon nitride film. Subsequently, when the substrate is exposed to the atmosphere, it reacts with moisture and other atmospheric substances, resulting in side etching and expansion impurities in the silicon nitride film, which may become obstacles in later steps. Therefore, it is preferable to perform in-system heat treatment on the substrate after etching the silicon nitride film to remove the ammonium fluoride silicon.

[0082] [Substrate Processing Methods]

[0083] Figure 5 This is a flowchart illustrating an example of a substrate processing method according to one embodiment. When this process begins, a substrate is transported to the etching chambers 11-14 to prepare the substrate (step S1). Furthermore, the etching target film formed on the substrate can be a silicon-containing film. The etching target film can be a silicon nitride film, a silicon oxide film, or a laminate of silicon oxide and silicon nitride films.

[0084] Next, a CF-based etching gas is supplied, and the CF-based gas plasma is used to etch the target film (step S2). The etching conditions at this time are as follows.

[0085] (Etching conditions)

[0086] Gas species: C4F8, H2, Ar

[0087] Pressure: 10mT~100mT (1.33Pa~13.3Pa),

[0088] Stage temperature (substrate temperature): -60℃~0℃

[0089] High-frequency electrical power HF: On.

[0090] After the etching target film on the substrate is etched under the above etching conditions, the substrate is transported in the in-system to the ashing processing chamber (step S3). Next, the temperature of the stage in the processing chamber where the substrate has been transported is set to a predetermined high temperature, and the substrate is heat-treated (baked) (step S4) to complete the process. The baking conditions at this time are as follows.

[0091] (Baking conditions)

[0092] Gas type: N2 gas or Ar gas,

[0093] Pressure: 1T~100T (133Pa~13300Pa).

[0094] In addition, Figure 3 During the heat treatment shown, the temperature of the stage 121 for heat treatment is higher than the temperature at which the reaction products of ammonium fluoride silicide are thermally decomposed. Furthermore, the temperature of the stage 121 is set to be lower than the lowest of the following temperatures: the temperature at which the etched target film on the substrate undergoes thermal deformation, the temperature at which the mask undergoes thermal deformation, and the temperature at which the tilted deposits attached to the tilted portion generated in the etching step undergo thermal deformation.

[0095] The inclined portion refers to the R portion (edge ​​portion) outside the flat portion on the back side of the substrate W. The inclined deposit refers to the reaction product of carbon and fluorine-containing CF polymers attached to the inclined portion.

[0096] For example, Figure 6 This is a graph showing an example of the modification or deformation temperatures for various materials. The modification or deformation temperatures for tilted deposits, photoresist (G line), organic films, monocrystalline silicon, silicon oxide, and silicon nitride are 250°C, 120°C, 500°C, 1414°C, 1710°C, and 1900°C, respectively.

[0097] In the substrate processing method of this embodiment, baking is performed at a temperature above the temperature at which ammonium fluoride decomposes and below the temperature at which the tilted deposits generated during etching do not peel off. For example, if the temperature at which ammonium fluoride decomposes is 120°C or higher and the temperature at which the tilted deposits do not peel off is less than 250°C, the temperature of the mounting stage is controlled to be 120°C or higher and less than 250°C to heat the substrate. However, for example, if another film on the substrate is modified at a temperature lower than the temperature at which the tilted deposits do not peel off, the temperature of the mounting stage is controlled to be such that all films on the substrate containing the other film do not undergo modification. For example, if the wiring layer deforms at the lowest temperature, the temperature of the mounting stage is controlled to be lower than the temperature at which the wiring layer deforms.

[0098] [Example]

[0099] Next, as an example, the experimental results of the heat treatment performed after the etching process in the above-described substrate processing method are referred to... Figure 7 and Figure 8 Please provide an explanation. Figure 7 This is a figure illustrating an example of the observation results of the etched object film after a heat treatment step in one embodiment. Figure 8 It means Figure 7 A figure showing an example of the observation results of the tilted deposits attached to the tilted portion R of the substrate.

[0100] Figure 7 The etched film shown is a laminate of silicon nitride film 110 and silicon oxide film 120. The etching and baking conditions are as described above. Figure 7 It is a portion of the cross-section formed by etching the gap shape in the laminated film, representing the result of shape observation 24 hours after the etching process. Figure 7 From top left, the figures show the cases where the substrate was not baked after etching, and the cases where it was baked at 60°C, 90°C, 120°C, 180°C, and 250°C after etching. Thus, in the cases where the substrate was not baked after etching, and in the cases where it was baked at 60°C and 90°C after etching, side etching occurred in the silicon nitride film 110. In contrast, in the cases where the substrate was baked at 120°C, 180°C, and 250°C, no side etching or expansion impurities occurred in the silicon nitride film 110. Furthermore, in the silicon oxide film 120, no side etching or expansion impurities occurred under any circumstances, regardless of whether it was baked.

[0101] Figure 8 It means Figure 7 The figure shows an example of the observation results of the inclined deposits attached to the inclined portion R on the back side of the substrate. When the temperature of the mounting stage on which the substrate is mounted is 120°C and 180°C, the inclined deposits attached to the inclined portion R do not peel off. On the other hand, when the temperature of the mounting stage is 250°C, the inclined deposits attached to the inclined portion R are peeled off.

[0102] Based on the above, and based on these results, it is known that the temperature at which ammonium fluoride decomposes is 120°C or higher, without side etching and expansion impurities. Furthermore, it is known that the temperature at which tilted deposits do not peel off is less than 250°C. Therefore, in the heat treatment step following the etching step, the temperature of the stage is controlled to be 120°C or higher but less than 250°C to heat the substrate. Thus, ammonium fluoride deposited on the sidewalls of the etched film can be removed without causing the tilted deposits to peel off from the tilted portion. This prevents damage to the etched film caused by ammonium fluoride contained in reaction products containing silicon, nitrogen, and fluorine deposited on the etched film.

[0103] [Cleaning equipment]

[0104] Finally, refer to Figure 9 The cleaning device 2 according to one embodiment will be described. Figure 9 This is a diagram illustrating an example of a cleaning device 2 according to one embodiment.

[0105] The cleaning device 2 includes a processing container 300, a mounting stage 301 (mounting platform) capable of holding a substrate W, an upper electrode 302 opposite to the mounting stage 301, and a support 303 for suspending the upper electrode 302. The processing container 300 is provided with a conveying port (not shown) for feeding and feeding the substrate W in and out, and a gate valve for opening and closing the conveying port.

[0106] The support portion 303 extends through the processing container 300 and is connected to a drive portion (not shown). The upper electrode 302 moves vertically by the drive portion causing the support portion 303 to move vertically. A bellows (not shown) is used to vacuum seal the wall of the processing container 300 and the support portion 303 outside the processing container 300. The support portion 303 has a gas supply portion 330 from which inactive gases such as N2 are supplied to the center of the substrate W. An upper gas supply portion 310 and a lower gas supply portion 320 extend through the sidewall of the processing container 300. The upper gas supply portion 310 and the lower gas supply portion 320 laterally supply O2 gas, as an example of a cleaning gas, near the outer periphery of the substrate W on the stage 301.

[0107] A substrate W, on which the pattern of the etch target film is etched by a mask, is placed on a stage 301. High-frequency electrical power for plasma generation is applied to the stage 301 by a high-frequency power source (not shown). This generates O2 gas plasma around the outer periphery of the substrate W. At this time, by making the space between the stage 301 and the upper electrode 302 narrower than the range of the plasma sheath, no plasma is generated in this space. Thus, O2 gas plasma is generated around the outer periphery of the substrate W, and the oxygen plasma asheens the tilted deposits attached to the tilted portion R of the substrate W. Alternatively, high-frequency electrical power from the high-frequency power source can be applied to the upper electrode 302.

[0108] A heater 305 is embedded in the mounting stage 301. An AC voltage is applied to the heater 305 from the AC power supply 304, heating the substrate on the mounting stage 301 to a predetermined temperature. The control unit 370 maintains the temperature of the mounting stage 301 at 120°C or higher. This causes the ammonium fluoride silicon deposited on the etched film generated during etching to decompose due to heat. The decomposed ammonium fluoride silicon is then purged from the center of the substrate to the outer periphery by N2 gas supplied from the gas supply unit 330, pushed to the outer periphery of the substrate W, and discharged to the outside through an exhaust device (not shown).

[0109] As described above, the cleaning apparatus 2 with this structure ashing process is performed by using oxygen plasma to ashed the tilted deposits attached to the tilted portion R of the substrate W, while simultaneously decomposing the ammonium fluoride silicon film deposited on the substrate W by heat treatment at a temperature above 120°C. Thus, both the tilted deposits and the ammonium fluoride silicon can be removed simultaneously.

[0110] Furthermore, the temperature of the stage 301 is higher than the temperature at which the ammonium fluoride deposited on the etch target film can thermally decompose, and is set to a temperature lower than the lowest of the temperatures at which the etch target film and the mask undergo thermal deformation. Moreover, the temperature of the stage 301 is set to a temperature higher than the temperature at which tilted deposits can be removed. Thus, both the ammonium fluoride and tilted deposits can be removed while preventing thermal deformation of the etch target film and the mask.

[0111] The above describes etching a silicon-containing film containing nitrogen (N) as the etching target film, but it is not limited to this. For example, when etching a silicon-containing film that does not contain nitrogen (N) as the etching target film, a gas containing nitrogen (N) and hydrogen (H) can be used as the etching gas in addition to a CF-based gas.

[0112] Furthermore, the reaction products deposited on the etchable film may contain ammonium fluoride, but this is not a limitation. For example, when etching the etchable film in the presence of nitrogen (N), hydrogen (H), and halogens, reaction products containing ammonium halides may be deposited on the etchable film. Examples of halogens include fluorine (F), chloride (Cl), bromine (Br), and iodine (I), while examples of ammonium halides include ammonium fluoride, ammonium chloride, ammonium bromide, and ammonium iodide. It is believed that when the substrate is exposed to the atmosphere in a state where reaction products containing ammonium halides have been deposited, the reaction products may react with moisture in the atmosphere, resulting in side etching or expansion impurities in the silicon nitride film, which could hinder subsequent steps. In addition, by setting the temperature of the stage 301 higher than the temperature at which the ammonium halides thermally decompose, the occurrence of side etching or expansion impurities can be suppressed.

[0113] It should be understood that the substrate processing method, substrate processing apparatus, and cleaning apparatus of one embodiment of the present invention are illustrative in all respects and not limiting. The above embodiments can be modified and improved in various ways without departing from the scope and spirit of the appended claims. The contents described in the above embodiments can be supplemented with other structures and combined without contradiction.

[0114] The substrate processing apparatus of the present invention can also be applied to any type of apparatus, including Atomic Layer Deposition (ALD), Capacitively Coupled Plasma (CCP), Inductively Coupled Plasma (ICP), Radial Line Slot Antenna (RLSA), Electron Cyclotron Resonance Plasma (ECR), and Helicon Wave Plasma (HWP).

Claims

1. A substrate processing method, characterized in that, include: The step of preparing a substrate containing a laminated film and a mask formed by alternately stacking multiple silicon oxide films and multiple silicon nitride films; The step of etching the laminated film with plasma through the mask to form a recess in the laminated film and forming a reaction product containing ammonium fluoride or ammonium halide on the sidewall of the recess; The step of ashing the inclined deposits attached to the inclined portion of the substrate after the etching step; and After the etching step, the substrate is heat-treated at a specified temperature to remove the reaction products from the sidewalls of the recess. The ashing of the tilted deposit and the heat treatment of the substrate are performed simultaneously, and the heat treatment chamber for the substrate is different from the etching chamber. In the steps of ashing the tilted deposits and removing the reaction products, the temperature of the stage on which the substrate is placed is set to 120°C or higher but less than 250°C.

2. The substrate processing method as described in claim 1, characterized in that: The ammonium halide includes at least one of ammonium fluoride, ammonium chloride, ammonium bromide, and ammonium iodide.

3. The substrate processing method as described in claim 1 or 2, characterized in that: The steps of forming the reaction products and removing the reaction products are performed in a manner that prevents the substrate from being exposed to the atmosphere.

4. A substrate processing apparatus comprising a processing container, a stage for holding a substrate, and a control unit, characterized in that: The control unit controls the execution of the following steps: The step of preparing a substrate containing a laminated film and a mask formed by alternately stacking multiple silicon oxide films and multiple silicon nitride films, and placing the substrate on the mounting stage; The step of etching the laminated film with plasma through the mask to form a recess in the laminated film and forming a reaction product containing ammonium fluoride or ammonium halide on the sidewall of the recess; The step of ashing the inclined deposits attached to the inclined portion of the substrate after the etching step; and After the etching step, the substrate is heat-treated at a specified temperature to remove the reaction products from the sidewalls of the recess. The control unit controls the ashing of the tilted deposit and the heat treatment of the substrate to be performed simultaneously, and in the steps of ashing the tilted deposit and removing the reaction products, the temperature of the stage on which the substrate is placed is set to 120°C or higher and less than 250°C.

5. A cleaning apparatus comprising a processing container, a stage for holding a substrate, and a control unit, characterized in that: The control unit controls the execution of the following steps: The step of preparing a substrate containing a laminated film and a mask formed by alternately stacking multiple silicon oxide films and multiple silicon nitride films, and placing the substrate on the mounting stage; The step of etching the laminated film with plasma through the mask to form a recess in the laminated film and forming a reaction product containing ammonium fluoride or ammonium halide on the sidewall of the recess; The step of ashing the inclined deposits attached to the inclined portion of the substrate after the etching step; and After the etching step, the substrate is heat-treated to remove the reaction products from the sidewalls of the recess. The control unit controls the ashing of the tilted deposit and the heat treatment of the substrate to be performed simultaneously, and in the steps of ashing the tilted deposit and removing the reaction products, the temperature of the stage on which the substrate is placed is set to 120°C or higher and less than 250°C.

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