Film forming method, protective film, and substrate processing apparatus

Abstract

To provide a method of forming a protective film for suppressing generation of particles, and to provide the protective film and a substrate processing apparatus.SOLUTION: A film forming method of forming a protective film on a surface of a member in a processing chamber in a plasma processing apparatus, the method including supplying a processing gas including a first silicon-containing gas that does not include hydrogen and fluorine and includes silicon and a first oxygen-containing gas including oxygen into the processing chamber, supplying a high frequency power for generating plasma to an upper electrode, and forming a silicon oxide film on the surface of the member by plasma generated from the processing gas including the first silicon-containing gas and the first oxygen-containing gas.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a film forming method, a protective film, and a substrate processing apparatus. [Background technology]

[0002] Patent Document 1 discloses a plasma processing method characterized by including a supply step of supplying into a chamber a mixed gas containing a compound gas containing silicon and a halogen element, an oxygen-containing gas, and an additive gas containing the same type of halogen element as the halogen element contained in the compound gas but not containing silicon element, and a film formation step of forming a protective film on a surface of a member in the chamber by using plasma of the mixed gas supplied into the chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-009403 Summary of the Invention [Problem to be solved by the invention]

[0004] In one aspect, the present disclosure provides a method for forming a protective film that suppresses particle generation, a protective film, and a substrate processing apparatus. [Means for solving the problem]

[0005] In order to solve the above problem, according to one aspect, there is provided a film formation method for forming a protective film on the surface of a member in a processing chamber of a plasma processing apparatus, the film formation method comprising: supplying a processing gas containing a first silicon-containing gas that does not contain hydrogen or fluorine but contains silicon, and a first oxygen-containing gas that contains oxygen into the processing chamber; supplying high-frequency power to an upper electrode to generate plasma; and forming a silicon oxide film on the surface of the member by the plasma generated from the processing gas containing the first silicon-containing gas and the first oxygen-containing gas. [Effects of the Invention]

[0006] According to one aspect, it is possible to provide a method for forming a protective film that suppresses particle generation, a protective film, and a substrate processing apparatus. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a vertical cross-sectional view showing an example of a plasma processing apparatus. [Figure 2] 1 is a flowchart showing an example of a plasma processing method. [Figure 3] Particle count ratio adhering to the substrate immediately after pre-coating. [Figure 4] Particle count ratio adhering to the substrate immediately after pre-coating. [Figure 5] 1 is a graph showing the bond energy between atoms of a silicon-containing gas and Si. [Figure 6] 1 is a graph showing the electronegativity of atoms of a silicon-containing gas. [Figure 7] 10 is a graph showing an example of the film density of a protective film relative to the flow rate ratio of SiF4 / SiCl4 and the power density of high-frequency power supplied to a high-frequency antenna. [Figure 8] 10 is an example of a graph showing the film density of a protective film relative to the power density of high-frequency power supplied to a high-frequency antenna. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0009] [Plasma processing equipment] The plasma processing apparatus 100 will be described with reference to Fig. 1. Fig. 1 is a vertical cross-sectional view showing an example of the plasma processing apparatus 100.

[0010] The plasma processing apparatus 100 shown in FIG. 1 is an inductively coupled plasma (ICP) processing apparatus that performs various substrate processing methods on a rectangular substrate G (hereinafter simply referred to as "substrate") for a flat panel display (hereinafter referred to as "FPD") in a planar view. The substrate is primarily made of glass, although transparent synthetic resin may also be used depending on the application. Substrate processing includes film formation using a chemical vapor deposition (CVD) method. Examples of FPDs include liquid crystal displays (LCDs), electroluminescence (EL), and plasma display panels (PDPs). The substrate may be a substrate having a circuit patterned on its surface, as well as a supporting substrate. Furthermore, the planar dimensions of FPD substrates have become larger with each generation, and the planar dimensions of the substrate G processed by the plasma processing apparatus 100 range at least from approximately 1500 mm × 1800 mm for the sixth generation to approximately 3000 mm × 3400 mm for the 10.5th generation. The thickness of the substrate G is approximately 0.2 mm to several mm.

[0011] 1 includes a processing vessel 20 having a rectangular box shape, a substrate mounting table (mounting table) 70 having a rectangular outer shape in a plan view that is disposed in the processing vessel 20 and on which a substrate G is mounted, and a control unit 90. The processing vessel 20 may have a cylindrical box shape or an elliptical cylindrical box shape, and in this configuration, the substrate mounting table also has a circular or elliptical shape, and the substrate mounted on the substrate mounting table also has a circular or elliptical shape.

[0012] Processing vessel 20 is divided into two spaces, upper and lower, by metal window 30, with antenna chamber A, which is the upper space, being formed by upper chamber 13, and processing chamber S, which is the lower space, being formed by lower chamber 17. In processing vessel 20, a rectangular ring-shaped support frame 14 is disposed at the boundary between upper chamber 13 and lower chamber 17 so as to protrude into the inside of processing vessel 20, and metal window 30 is attached to support frame 14.

[0013] An upper chamber 13 forming the antenna room A is formed by a side wall 11 and a top plate 12, and is made entirely of a metal such as aluminum or an aluminum alloy.

[0014] The lower chamber 17, which houses the processing chamber S, is formed by a sidewall 15 and a bottom plate 16, and is made entirely of a metal such as aluminum or an aluminum alloy. The sidewall 15 is grounded by a grounding wire 21. The sidewall 15 is also provided with a temperature control medium flow path, a feed pipe, and a return pipe (none of which are shown), which are connected to a chiller 86, which will be described later.

[0015] The support frame 14 is made of a conductive metal such as aluminum or an aluminum alloy, and can also be called a metal frame. The support frame 14 is provided with a temperature control medium flow path, a feed pipe, and a return pipe (none of which are shown), which are connected to a chiller 86, which will be described later.

[0016] A rectangular annular (endless) seal groove 22 is formed at the upper end of the side wall 15 of the lower chamber 17, and a seal member 23 such as an O-ring is fitted into the seal groove 22, and the seal member 23 is held by the abutting surface of the support frame 14, thereby forming a seal structure between the lower chamber 17 and the support frame 14.

[0017] A loading / unloading port 15a is formed in the side wall 15 of the lower chamber 17 to load and unload the substrate G into and from the lower chamber 17, and the loading / unloading port 15a is configured to be freely opened and closed by a gate valve 24. A transfer chamber (neither of which is shown) containing a transfer mechanism is adjacent to the lower chamber 17, and the gate valve 24 is controlled to open and close, and the substrate G is loaded and unloaded by the transfer mechanism through the loading / unloading port 15a.

[0018] Furthermore, a plurality of exhaust ports 16a are provided in the bottom plate 16 of the lower chamber 17. Each exhaust port 16a is connected to an exhaust device 300 via an exhaust flow path 301a. A pressure gauge (not shown) is installed at an appropriate position in the lower chamber 17, and information monitored by the pressure gauge is sent to the control unit 90.

[0019] The substrate mounting table 70 includes a base material 71 and an electrostatic chuck 76 formed on an upper surface 71 a of the base material 71 .

[0020] The base material 71 has a rectangular shape in a plan view, and has planar dimensions approximately the same as those of the substrate G to be placed on the substrate mounting table 70. That is, the mounting surface of the substrate mounting table 70 on which the substrate is placed has planar dimensions approximately the same as those of the substrate. In other words, the mounting surface of the substrate mounting table 70 has an area approximately the same as that of the substrate. The length of the long side of the base material 71 can be set to approximately 1800 mm to 3400 mm, and the length of the short side can be set to approximately 1500 mm to 3000 mm. With respect to these planar dimensions, the thickness of the base material 71 can be, for example, approximately 50 mm to 100 mm.

[0021] The base material 71 is provided with a temperature control medium flow path 72a that snakes so as to cover the entire area of ​​the rectangular plane, and is made of stainless steel, aluminum, an aluminum alloy, or the like. The temperature control medium flow path 72a may also be provided in the electrostatic chuck 76. Furthermore, the base material 71 may not be made of a single member as in the illustrated example, but may be made of a laminate of two members made of aluminum, an aluminum alloy, or the like.

[0022] A box-shaped pedestal 78 made of an insulating material and having a step on the inside is fixed on the bottom plate 16 of the lower chamber 17, and the substrate mounting table 70 is placed on the step of the pedestal 78.

[0023] An electrostatic chuck 76 on which a substrate G is directly placed is formed on an upper surface 71a of the base material 71. The electrostatic chuck 76 has a ceramic layer 74, which is a dielectric coating formed by thermally spraying a ceramic such as alumina, and a conductive layer 75 (attraction electrode) that is embedded inside the ceramic layer 74 and has an electrostatic attraction function.

[0024] The conductive layer 75 is connected to a DC power supply 85 via a power supply line 84. When a switch (not shown) on the power supply line 84 is turned on by the control unit 90, a DC voltage is applied from the DC power supply 85 to the conductive layer 75, thereby generating a Coulomb force. Due to this Coulomb force, the substrate G is electrostatically attracted to the upper surface of the electrostatic chuck 76 and is held in a state where it is placed on the upper surface 71 a of the base material 71.

[0025] A temperature control medium flow path 72a is provided on a base material 71 that constitutes the substrate mounting table 70, and the temperature control medium flow path 72a is formed to meander so as to cover the entire area of ​​a rectangular plane. Both ends of the temperature control medium flow path 72a are connected to a feed pipe 72b through which the temperature control medium is supplied to the temperature control medium flow path 72a, and a return pipe 72c through which the temperature control medium that has been heated after flowing through the temperature control medium flow path 72a is discharged.

[0026] As shown in FIG. 1 , a feed flow path 87 and a return flow path 88 are connected to the feed pipe 72b and the return pipe 72c, respectively. The feed flow path 87 and the return flow path 88 are connected to a chiller 86. The chiller 86 includes a main body that controls the temperature and discharge flow rate of the temperature-controlling medium, and a pump that pumps the temperature-controlling medium (neither of which is shown). A refrigerant is used as the temperature-controlling medium, such as Galden (registered trademark) or Fluorinert (registered trademark). The illustrated temperature control method involves circulating a temperature-controlling medium through the substrate 71. However, the substrate 71 may have a built-in heater or the like, and temperature control may be performed using the heater, or temperature control may be performed using both the temperature-controlling medium and the heater. Instead of using a heater, temperature control involving heating may be performed by circulating a high-temperature temperature-controlling medium. The heater, which is a resistor, is made of tungsten, molybdenum, or a compound of one of these metals with alumina, titanium, or the like. In the illustrated example, the temperature control medium flow path 72a is formed in the base material 71, but, for example, the electrostatic chuck 76 may also have a temperature control medium flow path. The sidewall 15 of the processing chamber S, the support frame 14, and the metal window conductor plate 32 (described later) are also connected to the chiller 86 by individual feed and return pipes (none of which are shown), and the temperatures are individually controlled by the flow of a temperature control medium. The temperature controllable ranges are, for example, 40°C or higher and 120°C or lower for the sidewall 15 and the support frame 14, 40°C or higher and 150°C or lower for the conductor plate 32, and 25°C or higher and lower than 350°C for the base material 71.

[0027] Temperature sensors (not shown), such as thermocouples, are provided on the sidewall 15, the support frame 14, the base material 71, and the conductor plate 32, and information monitored by the temperature sensors is transmitted to the control unit 90 as needed. Based on the transmitted monitoring information, the control unit 90 controls the temperatures of, for example, the base material 71 and the substrate G. More specifically, the control unit 90 adjusts the temperature and flow rate of the temperature-control medium supplied from the chiller 86 to the feed channel 87. The temperature- and flow-adjusted temperature-control medium is circulated through the temperature-control medium channel 72a, thereby controlling the temperature of the substrate mounting table 70. Similar temperature control is also performed on the sidewall 15, the support frame 14, and the conductor plate 32. The temperature sensors, such as thermocouples, may be provided on, for example, the electrostatic chuck 76.

[0028] A step is formed by the outer periphery of electrostatic chuck 76 and base 71 and the upper surface of pedestal 78, and a rectangular frame-shaped focus ring 79 is placed on this step. With focus ring 79 placed on the step, the upper surface of focus ring 79 is set lower than the upper surface of electrostatic chuck 76. Focus ring 79 is made of ceramics such as alumina, quartz, or the like.

[0029] A power supply member 80 is connected to the underside of the base material 71. A power supply line 81 is connected to the lower end of the power supply member 80, and the power supply line 81 is connected to a high-frequency power supply 83, which serves as a bias power supply, via a matcher 82 that performs impedance matching. When high-frequency power (second high-frequency power), for example, of 3.2 MHz, is applied to the substrate mounting table 70 from the high-frequency power supply 83, an RF bias is generated, and ions generated by the high-frequency power supply 56, which serves as a plasma generation source described below, can be attracted to the substrate G. In this manner, the substrate mounting table 70 forms a bias electrode that supports the substrate G and generates an RF bias. At this time, a portion of the lower chamber 17 that is at ground potential functions as a counter electrode of the bias electrode and forms a return circuit for the high-frequency power. The metal window 30 may also be configured as part of the return circuit for the high-frequency power. The metal window 30 is formed by a plurality of divided metal windows 31. The number of divided metal windows 31 that form the metal window 30 can be set to various numbers, such as 12 or 24.

[0030] The divided metal window 31 includes a conductor plate 32 and a shower plate 34. The divided metal window 31 also serves as a process gas outlet that discharges process gas into the process chamber S. Both the conductor plate 32 and the shower plate 34 are made of a nonmagnetic, conductive, corrosion-resistant metal or a metal with a corrosion-resistant surface treatment, such as aluminum, an aluminum alloy, or stainless steel. Examples of the corrosion-resistant surface treatment include anodizing and ceramic spraying. The exposed surface 34a of the shower plate 34 facing the process chamber S may be subjected to a plasma-resistant coating by anodizing or ceramic spraying. The conductor plate 32 is grounded via a ground wire (not shown), and the shower plate 34 is also grounded via the conductor plate 32, which is joined to the conductor plate 32. The conductor plate 32 is provided with a temperature control medium flow path, a feed pipe, and a return pipe (all not shown), which are connected to the chiller 86.

[0031] Each divided metal window 31 constituting the metal window 30 is suspended from the top plate 12 of the upper chamber 13 by a plurality of suspenders (not shown). A spacer (not shown) made of an insulating material is disposed above each divided metal window 31, and a high-frequency antenna (inductively coupled antenna) 51 is disposed at a distance from the conductor plate 32 by the spacer. The high-frequency antenna 51 contributes to plasma generation and is formed by winding an antenna wire made of a highly conductive metal such as copper in a circular or spiral shape. For example, multiple circular antenna wires may be disposed. The high-frequency antenna 51 is disposed on the top surface of the divided metal window 31, and is therefore suspended from the top plate 12 via the divided metal window 31. The high-frequency antenna 51 is disposed in an antenna chamber A of the upper chamber 13, above the processing vessel 20.

[0032] Gas diffusion grooves 33 are formed in the lower surface of the conductor plate 32, and through holes 32b are provided to connect the gas diffusion grooves 33 to the upper end surface 32a. Gas introduction pipes 52 are embedded in the through holes 32b. The shower plate 34 has a plurality of gas discharge holes 35 that connect the gas diffusion grooves 33 of the conductor plate 32 to the processing chamber S. The shower plate 34 is fastened to the lower surface of the conductor plate 32 in an area outside the gas diffusion grooves 33 with metal screws (not shown). The gas diffusion grooves may also be provided in the upper surface of the shower plate.

[0033] Each divided metal window 31 is electrically insulated from the support frame 14 and the adjacent divided metal window 31 by an insulating member 37. The insulating member 37 is made of a fluororesin such as PTFE (Polytetrafluoroethylene). An end face 37a of the insulating member 37 facing the processing chamber S is flush with the exposed face 34a of the shower plate 34 facing the processing chamber S, and an insulating cover member 38 is disposed across the exposed face 34a of the adjacent shower plate 34 while covering the end face 37a of the insulating member 37. The cover member 38 is made of ceramic such as alumina.

[0034] The insulating member 37 is made of a lightweight resin such as PTFE, which has high insulating properties. However, compared to ceramics such as alumina, resins are not as plasma-resistant. Furthermore, it is difficult to apply a plasma-resistant coating to the resin surface by anodizing or ceramic spraying. Therefore, in the plasma processing apparatus 100, the end surface 37a of the insulating member 37 facing the processing chamber S is covered with a ceramic cover member 38, for example, to protect the insulating member 37 from plasma. Each insulating member 37, which insulates the support frame 14 from the divided metal windows 31 and between adjacent divided metal windows 31, is covered with the cover member 38.

[0035] A power supply member 53 extending above the upper chamber 13 is connected to the high-frequency antenna 51, and a power supply line 54 is connected to the upper end of the power supply member 53. The power supply line 54 is connected to a high-frequency power source 56 via a matching box 55 that performs impedance matching.

[0036] When high frequency power (first high frequency power), for example, 13.56 MHz, is applied to the high frequency antenna 51 from the high frequency power supply 56, an inductive electric field is formed in the lower chamber 17. This inductive electric field converts the processing gas supplied from the shower plate 34 to the processing chamber S into plasma, generating inductively coupled plasma, and the components in the processing chamber S and the substrate G placed in the processing chamber S are exposed to the processing gas plasma. The metal window 30 exposed to the processing chamber S and on which the inductive electric field is formed is also referred to as an upper electrode.

[0037] The high frequency power supply 56 is a source for generating plasma, and the high frequency power supply 83 connected to the substrate mounting table 70 is a bias source that attracts the generated ions and imparts kinetic energy to them. In this way, the ion source generates plasma using inductive coupling, and a bias source, which is a separate power supply, is connected to the substrate mounting table 70 to control the ion energy, thereby independently generating plasma and controlling the ion energy, thereby increasing the degree of freedom in the process.

[0038] 1, the gas introduction pipes 52 of each divided metal window 31 are gathered together in one place inside the antenna chamber A, and the gas introduction pipes 52 extending upward pass airtight through the supply port 12a opened in the top plate 12 of the upper chamber 13. The gas introduction pipes 52 are then connected to a process gas supply source 64 via an airtightly joined gas supply pipe 61.

[0039] An on-off valve 62 and a flow rate controller 63 such as a mass flow controller are provided midway along the gas supply pipe 61. The gas supply pipe 61, the on-off valve 62, the flow rate controller 63, and the process gas supply source 64 form a process gas supply unit 60. The gas supply pipe 61 branches midway, and each branch pipe is connected to an on-off valve, a flow rate controller, and a process gas supply source appropriate for the type of process gas (not shown).

[0040] In plasma processing, processing gas is supplied from a processing gas supply unit 60 via a gas supply pipe 61 and a gas introduction pipe 52 to the gas diffusion grooves 33 of the conductor plate 32 of each divided metal window 31. Then, the processing gas is discharged from each gas diffusion groove 33 into the processing chamber S via the gas discharge holes 35 of each shower plate 34.

[0041] Alternatively, the gas inlet pipes 52 of the divided metal windows 31 may not be combined into one, but may each be individually connected to the process gas supply unit 60, and the supply of process gas may be controlled for each divided metal window 31. Alternatively, the gas inlet pipes 52 of multiple divided metal windows 31 located outside the metal window 30 may be combined into one, and the gas inlet pipes 52 of multiple divided metal windows 31 located inside the metal window 30 may be separately combined into one, and each gas inlet pipe 52 may be individually connected to the process gas supply unit 60, and the supply of process gas may be controlled. That is, in the former configuration, the supply of process gas is controlled for each divided metal window 31, and in the latter configuration, the supply of process gas is controlled separately for the external region and the internal region of the metal window 30. Furthermore, each divided metal window 31 may have its own radio-frequency antenna, and radio-frequency power may be applied to each radio-frequency antenna individually.

[0042] As described above, the plasma processing apparatus 100 includes a plasma generating unit that generates processing plasma for performing substrate processing (such as film formation processing) on ​​the substrate G. The plasma generating unit includes at least the metal window 30, the high-frequency antenna 51, and the high-frequency power supply 56. The high-frequency power supply 56 supplies high-frequency power to the high-frequency antenna 51, and the processing gas supply unit 60 supplies processing gas to the processing chamber S through the divided metal window 31 (processing gas discharge unit). The plasma generating unit forms an induction electric field within the processing chamber S, and generates plasma of the processing gas supplied into the processing chamber S by this induction electric field.

[0043] The control unit 90 controls the operation of each component of the plasma processing apparatus 100, such as the chiller 86, the high-frequency power supplies 56 and 83, the processing gas supply unit 60, and the exhaust unit 300 based on monitor information transmitted from a pressure gauge. The control unit 90 includes a central processing unit (CPU), a read-only memory (ROM), and a random access memory (RAM). The CPU executes a predetermined process in accordance with a recipe (process recipe) stored in the storage area of ​​the RAM or ROM. The recipe contains control information for the plasma processing apparatus 100 relative to process conditions. The control information includes, for example, the gas flow rate, the pressure in the processing chamber 20, the temperature in the processing chamber 20, the temperature of the substrate 71, and the process time.

[0044] The recipes and the programs applied by the control unit 90 may be stored, for example, on a hard disk, a compact disk, a magneto-optical disk, etc. Alternatively, the recipes and the like may be stored on a portable computer-readable storage medium such as a CD-ROM, a DVD, or a memory card and set in the control unit 90 so that they can be read out. The control unit 90 also has user interfaces such as input devices such as a keyboard and a mouse for inputting commands, a display device such as a display that visualizes and displays the operating status of the plasma processing apparatus 100, and an output device such as a printer.

[0045] <Processing method> Next, an example of a plasma processing method of the plasma processing apparatus 100 will be described with reference to Fig. 2. Fig. 2 is a flowchart showing the example of the plasma processing method. Here, the plasma processing apparatus 100 is a substrate processing apparatus that forms a silicon oxide film on a substrate G. The plasma processing apparatus 100 also forms a protective film inside a processing chamber 20.

[0046] In step S101, a precoating process is performed to form a protective film (precoat film) inside the processing vessel 20. Here, the plasma processing apparatus 100 is an apparatus for forming a silicon oxide film on a substrate G, and in the precoating process, a silicon oxide film is formed as a protective film. In addition, in the precoating process, a protective film is formed on the surfaces of components inside the processing chamber S. Specifically, the protective film is formed on the inside of the lower chamber 17 (the inner wall surface of the sidewall 15), the support frame 14, the shower plate 34, the cover member 38, the surface of the focus ring 79 facing the processing chamber S, the substrate mounting surface of the substrate mounting table 70, etc.

[0047] Here, the control unit 90 controls the process gas supply unit 60 to supply a process gas (first process gas) containing a first silicon-containing gas and a first oxygen-containing gas to the process chamber S. The control unit 90 also controls the high-frequency power supply 56 to supply high-frequency power to the high-frequency antenna 51. As a result, plasma of the process gas (first silicon-containing gas, first oxygen-containing gas) is generated in the process chamber S, the first silicon-containing gas and the first oxygen-containing gas are dissociated, and the dissociated first silicon-containing gas and the dissociated first oxygen-containing gas are reacted with each other to form a protective film of silicon oxide (SiOx) on the surfaces of the components in the process chamber S.

[0048] Here, the first silicon-containing gas may be a gas containing silicon (Si) but not containing fluorine (F). Alternatively, the first silicon-containing gas may be a gas containing silicon (Si) but not containing fluorine (F) or hydrogen (H). Specifically, the first silicon-containing gas may be SiCl4 gas.

[0049] The first oxygen-containing gas may be a gas containing oxygen (O). Specifically, the first oxygen-containing gas may be O 2 gas or N 2 O gas.

[0050] Furthermore, the power density (first power density) of the high frequency power supplied to the high frequency antenna 51 in step S101 is smaller than the power density (second power density) of the high frequency power supplied to the high frequency antenna 51 in step S103, which will be described later. The power density of the high frequency power indicates the power of the high frequency power supplied to the high frequency antenna 51 relative to the area of ​​the substrate mounting table 70 (mounting surface). Specifically, the power density (first power density) of the high frequency power supplied to the high frequency antenna 51 in step S101 is, for example, 1.8 kW / m per unit area of ​​the substrate in the plasma processing apparatus 100 for processing sixth generation substrates G. 2 ~3.7kW / m 2 It is preferable that the range is within the range of .

[0051] The temperature for forming the protective film is preferably less than 350° C. Specifically, the temperature for forming the protective film on the surface of each component is preferably 80° C. or more and 120° C. or less, more preferably 110° C. or more and 120° C. or less, for the side wall 15 and the support frame 14, 80° C. or more and 150° C. or less, more preferably 110° C. or more and 150° C. or less, for the conductor plate 32, and 200° C. or more and less than 350° C., more preferably 300° C. or more and less than 350° C. for the base material 71.

[0052] In step S102, an unprocessed substrate G is carried into the processing chamber S.

[0053] In step S103, a film formation process is performed on the substrate G. Here, a film formation process is performed to form a silicon oxide film (SiOx) on the substrate G. The control unit 90 controls the process gas supply unit 60 to supply a process gas (second process gas) containing a second silicon-containing gas and a second oxygen-containing gas to the process chamber S. The control unit 90 also controls the high-frequency power supply 56 to supply high-frequency power to the high-frequency antenna 51. As a result, plasma of the process gas (second silicon-containing gas, second oxygen-containing gas) is generated in the process chamber S, the second silicon-containing gas and the second oxygen-containing gas are dissociated, and the dissociated second silicon-containing gas and the dissociated second oxygen-containing gas are reacted with each other to form a silicon oxide film (SiOx) on the substrate G. The silicon oxide film (SiOx) is also deposited on components in the process chamber S.

[0054] Here, the second silicon-containing gas may be a gas containing silicon (Si) but not hydrogen (H). Alternatively, the second silicon-containing gas may be a gas containing silicon (Si) and fluorine (F) but not hydrogen (H). Specifically, the second silicon-containing gas may be a mixed gas of SiF4 gas and SiCl4 gas.

[0055] The second oxygen-containing gas may be a gas containing oxygen (O). Specifically, the second oxygen-containing gas may be O2 gas or N2O gas.

[0056] Furthermore, the power density (first power density) of the high frequency power supplied to the high frequency antenna 51 in step S103 is greater than the power density (second power density) of the high frequency power supplied to the high frequency antenna 51 in the above-described step S101. The power density of the high frequency power indicates the power of the high frequency power supplied to the high frequency antenna 51 relative to the area of ​​the substrate mounting table 70 (mounting surface). Specifically, the power density (second power density) of the high frequency power supplied to the high frequency antenna 51 in step S103 is 14.8 kW / m in the plasma processing apparatus 100 for processing sixth-generation substrates G. 2This range is preferable. As a result, the Si-F bond of the SiF4 gas and the Si-Cl bond of the SiCl4 gas are dissociated, and a silicon oxide film can be formed on the substrate G.

[0057] The temperature for forming the protective film is preferably less than 350° C. Specifically, the temperature for forming the protective film on the surface of each component is preferably 80° C. or more and 120° C. or less, more preferably 110° C. or more and 120° C. or less, for the side wall 15 and the support frame 14, 80° C. or more and 150° C. or less, more preferably 110° C. or more and 150° C. or less, for the conductor plate 32, and 200° C. or more and less than 350° C., more preferably 300° C. or more and less than 350° C. for the base material 71.

[0058] In step S104, the processed substrate G is carried out of the processing chamber S.

[0059] In step S105, it is determined whether or not the predetermined number of times has passed. If the predetermined number of times has not passed (S105: No), the process of the control unit 90 returns to step S102, and the next substrate G is processed (S102 to S104). If the predetermined number of times has passed (S105: Yes), the process of the control unit 90 proceeds to step S106.

[0060] In step S106, a cleaning process is performed to clean (remove) deposits accumulated inside the processing vessel 20. Here, the control unit 90 controls the processing gas supply unit 60 to supply a cleaning gas to the processing chamber S. The control unit 90 may also control the high-frequency power supply 56 to supply high-frequency power to the high-frequency antenna 51.

[0061] The cleaning gas may be, for example, NF3, CF4, etc. This removes reaction products containing silicon (Si) deposited inside the processing chamber 20. The protective film is also removed.

[0062] In step S107, it is determined whether or not the process is to be ended. If the process is not to be ended (S107: No), the process by the control unit 90 returns to step S101, where the pre-coating process is performed and the film forming process on the substrate G is continued. If the process is to be ended (S107: Yes), the process by the control unit 90 is ended.

[0063] In this manner, in the film formation process (S103) on the substrate G, a silicon oxide film is formed on the substrate G using a second silicon-containing gas that does not contain hydrogen (H) and a second oxygen-containing gas. This allows for a reduction in hydrogen in the silicon oxide film compared to when a silicon oxide film is formed using a silicon-containing gas that contains hydrogen (H), such as SiH4. Furthermore, for example, in a transistor using an oxide semiconductor, the hydrogen in the insulating film (the silicon oxide film formed in step S103) can be reduced, thereby suppressing fluctuations in transistor characteristics due to the influence of hydrogen in the film. Furthermore, in the film formation process (S103) on the substrate G, a silicon oxide film is formed on the substrate G using a second silicon-containing gas that contains fluorine (F) and a second oxygen-containing gas. This allows for an improvement in transistor characteristics, for example, in a transistor using an oxide semiconductor.

[0064] However, if a protective film is formed using a silicon-containing gas (SiF4) containing fluorine and an oxygen-containing gas (O2 or N2O) in the pre-coating process (S101), the adhesion to the upper electrode (metal window 30 including the conductor plate 32 and shower plate 34) is poor, and in the film formation process (S103) immediately after the pre-coating process (S101), the protective film may peel off from the upper electrode, etc., and the number of particles adhering to the substrate G may increase.

[0065] 3 shows the particle count ratio of particles adhering to a substrate G immediately after pre-coating. The power density of the high-frequency power indicates the power of the high-frequency power supplied to the high-frequency antenna 51 relative to the area of ​​the substrate mounting table 70 (mounting surface). Here, a mixed gas of SiF4 gas and SiCl4 gas (including the case where only one gas is used) is used as the silicon-containing gas, and O2 gas is used as the oxygen-containing gas to form the protective film. Note that the plasma processing apparatus 100 here will be described as an example of an apparatus that processes a sixth-generation substrate G (approximately 1500 mm × 1800 mm).

[0066] In (a), the ratio of the flow rate of SiF4 gas to the flow rate of the mixed gas of SiF4 gas and SiCl4 gas is 14.2%, and the power density of the high frequency power supplied to the high frequency antenna 51 is 3.7 kW / m 2 In (b), the ratio of the flow rate of SiF4 gas to the flow rate of the mixed gas of SiF4 gas and SiCl4 gas is 7.6%, and the power density of the high frequency power supplied to the high frequency antenna 51 is 3.7 kW / m 2 In (c), the ratio of the flow rate of SiF4 gas to the flow rate of the mixed gas of SiF4 gas and SiCl4 gas is 0% (i.e., SiCl4 gas only), and the power density of the high frequency power supplied to the high frequency antenna 51 is 3.7 kW / m 2 In (a) to (c), the film formation temperature is less than 350°C. Specifically, the temperatures of the side wall 15 and the support frame 14 were controlled at 110°C, the conductive plate 32 at 150°C, and the substrate 71 at 300°C. The vertical axis represents the particle count normalized to the count in (c) of 1.

[0067] 3, the lower the flow rate of SiF4, the lower the number of particles adhering to the substrate G. Furthermore, by using only SiCl4 gas as the silicon-containing gas shown in (c), the number of particles adhering to the substrate G can be reduced compared to the case where a mixed gas of SiF4 gas and SiCl4 gas shown in (a) and (b) is used.

[0068] 4 shows the particle count ratio of particles adhering to a substrate G immediately after pre-coating. The power density of the high-frequency power indicates the power of the high-frequency power supplied to the high-frequency antenna 51 relative to the area of ​​the substrate mounting table 70 (mounting surface). Here, the protective film was formed using SiCl4 gas as the silicon-containing gas and O2 gas as the oxygen-containing gas. Note that the plasma processing apparatus 100 here will be described as an example of an apparatus that processes a sixth-generation substrate G (approximately 1500 mm x 1800 mm).

[0069] In (a), the power density of the high frequency power supplied to the high frequency antenna 51 is 3.7 kW / m 2 In (b), the power density of the high frequency power supplied to the high frequency antenna 51 is 7.4 kW / m 2 In (c), the power density of the high frequency power supplied to the high frequency antenna 51 is 18.5 kW / m 2 In (a) to (c), the film formation temperature is less than 350°C. Specifically, the temperatures of the side wall 15 and the support frame 14 were controlled at 110°C, the conductive plate 32 at 150°C, and the substrate 71 at 300°C. The vertical axis represents the particle count normalized to the count in (c) of 1.

[0070] As shown in FIG. 4, the number of particles adhering to the substrate G decreases as the power density of the high frequency power supplied to the high frequency antenna 51 decreases.

[0071] Fig. 5 is a graph showing the bond energy between atoms of a silicon-containing gas and Si. Fig. 6 is a graph showing the electronegativity of atoms of a silicon-containing gas.

[0072] In the film formation process of a silicon oxide film (SiOx) using a silicon-containing gas containing SiF4, the Si-F bond energy of the SiF4 gas is high, so a high-power density high-frequency power must be supplied to the high-frequency antenna 51 for gas dissociation and film formation. It is also believed that an etching reaction of the silicon oxide film (SiOx) occurs due to F radicals dissociated from the SiF4 gas during film formation. Furthermore, because the electronegativity of F is high, the reaction products between the F radicals and the silicon oxide film (SiOx) are easily volatilized and susceptible to etching.

[0073] Therefore, in the initial stage of film formation, silicon (Si) and oxygen (O) molecules are adsorbed onto the substrate (such as the shower plate 34) to form a protective film (silicon oxide film), and the formation of the protective film (silicon oxide film) is inhibited by etching using F radicals, resulting in a long incubation time before the formation of the protective film begins.

[0074] In addition, an increase in the impurity concentration (fluorine (F) concentration) in the film is thought to reduce the adhesion between the substrate and the protective film. Also, depending on the material of the substrate (such as the shower plate 34), the underlying film may be scraped off, which is thought to reduce the adhesion between the substrate and the protective film.

[0075] In addition, the bond energy of Si-F is greater than that of Si-O (Si-F > Si-O), and silicon oxide films (SiOx) are easily etched by F radicals. Furthermore, the Si-F bonds in the film are strong during the film formation process, which may inhibit the bonds (network) with Si and O.

[0076] In contrast, in the pre-coating process of this embodiment, SiCl4 gas is used as the first silicon-containing gas, and O2 or N2O gas is used as the first oxygen-containing gas.

[0077] Since the Si—Cl bond energy of SiCl4 gas is lower than the Si—F bond energy of SiF4 gas, the power density of the high frequency power supplied to the high frequency antenna 51 can be suppressed.

[0078] In addition, the bonding energy of Si-Cl is smaller than that of Si-O (Si-Cl < Si-O), and it is possible to suppress the residual of Cl in the silicon oxide film (SiOx). As a result, the adhesion between the substrate and the protective film is improved.

[0079] Also, by using a first silicon-containing gas that does not contain fluorine (F), the etching effect by F radicals can be eliminated, the incubation time of the protective film can be shortened, and the adhesion of the protective film is improved.

[0080] In addition, in the precoat treatment, by suppressing the power density of the high-frequency power supplied to the high-frequency antenna 51, the amount of heat input from the plasma to the substrate on which the protective film is formed is also reduced. Therefore, the thermal expansion of the substrate is reduced, and it is possible to suppress the peeling of the protective film due to the thermal expansion of the substrate during the precoat treatment.

[0081] FIG. 7 is an example of a graph showing the film density of the protective film with respect to the flow rate ratio of SiF4 / SiCl4 and the power density of the high-frequency power supplied to the high-frequency antenna 51. The power density of the high-frequency power indicates the power of the high-frequency power supplied to the high-frequency antenna 51 with respect to the area of the substrate mounting table 70 (mounting surface). Here, a mixed gas of SiF4 gas and SiCl4 gas (including the case of only one gas) is used as the silicon-containing gas, and O2 gas is used as the oxygen-containing gas to form a protective film on a sample placed on the mounting surface of the substrate mounting table 70. Note that the plasma processing apparatus 100 here will be described by taking, as an example, an apparatus for processing a sixth-generation (about 1500 mm × 1800 mm) substrate G. In addition, in (a) to (c), the film formation temperature is less than 350°C. Specifically, the temperature control of the side wall 15 and the support frame 14 was performed at 110°C, the conductor plate 32 at 150°C, and the substrate 71 at 300°C.

[0082] The horizontal axis represents the flow rate ratio of SiF4 / SiCl4 in the silicon-containing gas. The vertical axis represents the film density of the formed protective film (silicon oxide film). In addition, the power density of the high-frequency power supplied to the high-frequency antenna 51 is 3.7 kW / m 2 The results are shown by black circles. When the power density of the high frequency power supplied to the high frequency antenna 51 is 11.1 kW / m 2 The results are shown by the open circles and solid lines. 2 The results are shown by open circles and dashed lines.

[0083] As shown by arrow 701, the film density increases as the flow rate ratio of SiF4 in the silicon-containing gas decreases. In other words, the etching resistance of the protective film improves as the flow rate ratio of SiF4 in the silicon-containing gas decreases. In other words, the quality of the protective film improves by using SiCl4 as the first silicon-containing gas.

[0084] Furthermore, as indicated by arrow 702, the film density decreases as the power density of the high-frequency power supplied to the high-frequency antenna 51 decreases. Therefore, when a mixed gas of SiF4 and SiCl4 is used as the silicon-containing gas, the protective film may not achieve the desired film density. In contrast, by using SiCl4 as the first silicon-containing gas, the protective film can achieve the desired film density. In other words, by using SiCl4 as the first silicon-containing gas, the power density of the high-frequency power supplied to the high-frequency antenna 51 can be reduced while the protective film achieves the desired film density.

[0085] In this way, a protective film is formed by plasma generated from a processing gas containing the first silicon-containing gas (SiCl) and the first oxygen-containing gas (O or N O), and the film density of the protective film is 2.18 g / cm 3 It is preferable to do the following:

[0086] 8 is an example of a graph showing the film density of a protective film versus the power density of the high-frequency power supplied to the high-frequency antenna 51. Here, SiCl4 gas was used as the silicon-containing gas and O2 gas was used as the oxygen-containing gas to form a protective film on a sample placed on the mounting surface of the substrate mounting table 70. Note that the plasma processing apparatus 100 here is described as an apparatus for processing a sixth-generation substrate G (approximately 1500 mm × 1800 mm). Also, in (a) to (c), the film formation temperature is less than 350°C. Specifically, the sidewall 15 and support frame 14 were temperature-controlled at 110°C, the conductor plate 32 at 150°C, and the base material 71 at 300°C.

[0087] The horizontal axis represents the power density of the high-frequency power supplied to the high-frequency antenna 51. The vertical axis represents the film density of the formed protective film (silicon oxide film). The power density of the high-frequency power represents the power of the high-frequency power supplied to the high-frequency antenna 51 relative to the area of ​​the substrate mounting table 70 (mounting surface).

[0088] The power density of the high frequency power supplied to the high frequency antenna 51 is 1.8 [kW / m 2 ] or more, 3.6[kW / m 2 ] or less (shown as range 801 in FIG. 8).

[0089] The power density of the high frequency power supplied to the high frequency antenna 51 is set to 3.6 [kW / m 2 ] or less, peeling of the protective film from the upper electrode and the like can be suppressed in the film forming process (S103) immediately after the pre-coating process (S101), and the number of particles adhering to the substrate G can be suppressed.

[0090] The power density of the high frequency power supplied to the high frequency antenna 51 is set to 1.8 [kW / m 2 ] or more, the first silicon-containing gas (SiCl4) and the first oxygen-containing gas (O2 or N2O) can be dissociated.

[0091] The pre-coating process may include a first step of supplying a first silicon-containing gas (SiCl4 gas) and a first oxygen-containing gas (O2 gas or N2O gas) and supplying high-frequency power at a first power density (low power density) to the high-frequency antenna 51, and a second step of supplying a second silicon-containing gas (a mixed gas of SiF4 gas and SiCl4 gas) and a second oxygen-containing gas (O2 gas or N2O gas) and supplying high-frequency power at a second power density (high power density) to the high-frequency antenna 51 after the first step. That is, by forming a silicon oxide film using a silicon-containing gas that does not contain fluorine (F) and a first power density in the initial stage of protective film formation, the incubation time can be shortened and the adhesion of the protective film to the substrate can be improved. Then, the protective film may be formed under the same conditions as in the film formation process (S103) for the substrate G. This can prevent film peeling.

[0092] Although the substrate mounting stage having an electrostatic chuck function, a temperature control medium flow path, and a heater, or an electrostatic chuck function and a heater, has been described as an example of a plasma processing apparatus, it is of course also possible to use a substrate mounting stage that has a temperature control medium flow path and a heater without an electrostatic chuck function, or a substrate mounting stage that has a heater without an electrostatic chuck function.

[0093] The above describes embodiments of the plasma processing method, but the present disclosure is not limited to the above embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure as described in the claims. [Explanation of symbols]

[0094] G board Antenna Room A S Processing Room 100 Plasma processing device 20 Processing container 30 Metal window (plasma generation section) 31 Split metal window 32 Conductor plate 34 shower plate 38 Cover member 51 High frequency antenna (plasma generation part) 56 High frequency power supply (plasma generating part) 60 Processing gas supply unit 70 Board mounting table 90 Control Unit

Claims

1. 1. A method for forming a protective film on a surface of a member in a processing chamber of a plasma processing apparatus, comprising: supplying a processing gas containing a first silicon-containing gas containing silicon but not containing hydrogen or fluorine and a first oxygen-containing gas containing oxygen into the processing chamber; and supplying high-frequency power to the upper electrode to generate plasma; forming a silicon oxide film on the surface of the member by plasma generated from the processing gas containing the first silicon-containing gas and the first oxygen-containing gas; Film formation method.

2. The first silicon-containing gas is SiF ４ Does not include The film forming method according to claim 1 .

3. The first silicon-containing gas is SiCl ４ That is, The film forming method according to claim 2 .

4. The first oxygen-containing gas is O ２ or N ２ It is O. The film forming method according to claim 3 .

5. The high frequency power supplied to the upper electrode is 1.8 kW / m with respect to the area of ​​the mounting surface of the substrate mounting table disposed in the processing chamber ２ Above, 3.7kW / m ２ Below is the The film forming method according to any one of claims 1 to 4.

6. The film formation temperature for forming the silicon oxide film is less than 350°C. The film forming method according to any one of claims 1 to 4.

7. In a plasma processing apparatus, a protective film is formed on a surface of a member in a processing chamber, The plasma is formed by plasma generated from a process gas including a first silicon-containing gas that does not include hydrogen or fluorine but includes silicon, and a first oxygen-containing gas that includes oxygen; The film density is 2.18 g / cm ３ The silicon oxide film is: protective film.

8. a processing vessel having a processing chamber; a substrate mounting table provided in the processing chamber; a processing gas supply unit that supplies a processing gas into the processing chamber; a plasma generating unit that generates plasma of the processing gas; a control unit, The control unit The apparatus is configured to be capable of performing a step of forming a protective film on a surface of a member in the processing chamber by plasma generated from a processing gas including a first silicon-containing gas that does not include hydrogen or fluorine but does include silicon, and a first oxygen-containing gas that includes oxygen. Substrate processing equipment.

9. The control unit After the step of forming the protective film, the plasma processing apparatus is configured to be capable of performing a step of forming a silicon oxide film on a substrate placed on the substrate placement table by using plasma generated from a process gas including a second silicon-containing gas that does not include hydrogen but contains silicon and fluorine, and a second oxygen-containing gas that contains oxygen. The substrate processing apparatus according to claim 8 .

10. The first silicon-containing gas is SiCl ４ and The first oxygen-containing gas is O ２ or N ２ O, The second silicon-containing gas is SiF ４ and SiCl ４ is a gas mixture of The second oxygen-containing gas is O ２ or N ２ It is O. The substrate processing apparatus according to claim 9 .

11. a power density of the high frequency power supplied to the upper electrode in the step of forming the protective film is lower than a power density of the high frequency power supplied to the upper electrode in the step of forming a silicon oxide film on the substrate; The substrate processing apparatus according to claim 9 or 10.

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