Method and apparatus for forming silicon nitride film

Abstract

Provided are a method and an apparatus for forming a silicon nitride film. A method for forming a silicon nitride film on a substrate housed in a processing chamber, the method comprising: a step (a) in which a gas containing a silicon halide gas is supplied into the processing chamber without supplying high-frequency power; a step (b) in which, after the step (a), the supply of the gas containing the silicon halide gas is stopped, and the inside of the processing chamber is exhausted; a step (c), after the step (b), supplying a nitrogen-containing gas into the processing chamber; a step (d), after the steps (c), for generating plasma by supplying high-frequency power into the processing chamber; after the steps (e) and (d), stopping the supply of the nitrogen-containing gas and the supply of the high-frequency power, and exhausting the inside of the processing chamber; and repeating the steps of (a) to (e) for X times (X > = 1) until a silicon nitride film having a predetermined film thickness is formed, wherein the substrate temperature is controlled to 100 DEG C or less in the steps (a) to (e).

Description

[0001] This application is a divisional application of an application with an application date of November 9, 2021, application number 202111318553.8, and invention name “Film forming method and film forming device for silicon nitride film”. Technical Field

[0002] The present disclosure relates to a film forming method and a film forming apparatus for forming a silicon nitride film. Background Art

[0003] For example, Patent Documents 1 and 2 propose the following method: a process of alternately supplying a silicon-containing raw material gas and a nitrogen-containing gas while purging the residual gas in the chamber is repeated, and a silicon nitride film is formed by an ALD (Atomic Layer Deposition) method. In the above film forming method, the temperature of the substrate is controlled to about 300° C. to 650° C. during the process.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-64924

[0007] Patent Document 2: Japanese Patent Application Publication No. 2000-114257 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] The present disclosure provides a film forming method and a film forming apparatus capable of forming a silicon nitride film with good coverage in an environment where the temperature of a substrate is 200° C. or less.

[0010] Solutions for solving problems

[0011] According to one embodiment of the present disclosure, a method for forming a silicon nitride film is provided, which is a method for forming a silicon nitride film on a substrate accommodated in a processing chamber, and the film forming method comprises the following steps: step (a), supplying a gas containing a silicon halide gas into the aforementioned processing chamber without supplying high-frequency power; step (b), after the aforementioned step (a), stopping the supply of the aforementioned gas containing a silicon halide gas and exhausting the aforementioned processing chamber; step (c), after the aforementioned step (b), supplying a nitrogen-containing gas into the aforementioned processing chamber. gas; step (d), after the step (c), supplying the high-frequency power into the processing chamber to generate plasma; step (e), after the step (d), stopping the supply of the nitrogen-containing gas and the supply of the high-frequency power to exhaust the processing chamber; and repeating the steps (a) to (e) for X times (X ≥ 1) until the silicon nitride film of a predetermined film thickness is formed, wherein the temperature of the substrate is controlled to be below 200°C in the steps (a) to (e).

[0012] According to another embodiment of the present disclosure, a method for forming a silicon nitride film is provided, which is a method for forming a silicon nitride film on a substrate in a processing chamber accommodated in a processing chamber, the processing chamber comprising: a mounting table for mounting the substrate; a high-frequency antenna, which is arranged above the mounting table and is used to form an inductively coupled plasma; a shower head, which is arranged between the mounting table and the high-frequency antenna, and the film forming method comprises the following steps: step (a), supplying a gas containing a silicon halide gas from the shower head into the processing chamber without supplying high-frequency power to the high-frequency antenna; step (b), after step (a), stopping the supply of the gas containing a silicon halide gas, exhausting the processing chamber and decompression; step (c), supplying a nitrogen-containing gas into the processing chamber after step (b); step (d), supplying the high-frequency power to the high-frequency antenna after step (c) to generate the inductively coupled plasma in the processing chamber; step (e), after step (d), stopping the supply of the nitrogen-containing gas and the supply of the high-frequency power, exhausting and decompressing the processing chamber; and, repeating steps (a) to (e) X times in the same processing chamber of the processing chamber until the silicon nitride film of a predetermined film thickness is formed, wherein X ≥ 1, and in the steps (a) to (e), the temperature of the substrate is controlled to be below 100°C.

[0013] According to another embodiment of the present disclosure, there is provided a film forming device for forming a silicon nitride film on a substrate in a processing chamber accommodated in a processing chamber, the film forming device comprising a processing chamber and a control unit, the processing chamber comprising: a mounting table for mounting the substrate; a high-frequency antenna, which is arranged above the mounting table and is used to form an inductively coupled plasma; a shower head, which is arranged between the mounting table and the high-frequency antenna, the control unit being used to control the following steps: step (a), supplying a gas containing a silicon halide gas from the shower head into the processing chamber without supplying high-frequency power to the high-frequency antenna; step (b), after step (a), stopping the supply of the gas containing a silicon halide gas and exhausting the processing chamber and decompressing the chamber; step (c), supplying a nitrogen-containing gas from the shower head into the processing chamber after the step (b); step (d), supplying the high-frequency power to the high-frequency antenna after the step (c) to generate an inductively coupled plasma in the processing chamber; step (e), after the step (d), stopping the supply of the nitrogen-containing gas and the supply of the high-frequency power, exhausting the chamber and decompressing the chamber; and, repeating the steps (a) to (e) X times in the same processing chamber of the processing chamber until the silicon nitride film of a predetermined film thickness is formed, wherein X ≥ 1, and further, controlling the temperature of the substrate to be below 100°C in the steps (a) to (e).

[0014] Effects of the Invention

[0015] According to one aspect, a silicon nitride film having good coverage can be formed in an environment where the temperature of the substrate is 200° C. or lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic cross-sectional view showing an example of the organic EL device according to the embodiment.

[0017] Figure 2 It is a schematic cross-sectional view showing an example of a film forming apparatus according to an embodiment.

[0018] Figure 3 This is a flowchart showing an example of a film forming method according to an embodiment.

[0019] Figure 4 This is a timing chart showing an example of the film forming method according to the embodiment.

[0020] Figure 5 It is a diagram showing an example of the evaluation of the characteristics of the silicon nitride film by the film forming method according to the embodiment and the comparative example.

[0021] Description of Reference Numerals

[0022] 10Processing chamber

[0023] 60 substrate mounting table

[0024] 100 film forming device

[0025] 110 Light-emitting element driving circuit layer

[0026] 120 Anode

[0027] 130 hole injection layer

[0028] 114 hole transport layer

[0029] 115 organic light emitting layer

[0030] 116 Electron transport layer

[0031] 150 transistor components

[0032] 160 banks

[0033] 180 electron injection layer

[0034] 190 cathode

[0035] 200 organic EL devices

[0036] 220 Sealing Film DETAILED DESCRIPTION

[0037] Hereinafter, the mode for implementing the present disclosure will be described with reference to the drawings. In each of the drawings, the same components are denoted by the same reference numerals, and duplicate descriptions may be omitted.

[0038] [Organic EL devices]

[0039] Organic EL devices are characterized by being intolerant to moisture. Therefore, in the manufacturing process of organic EL devices, there is a process in which a silicon nitride film is formed as a sealing film for protecting the organic EL device from external moisture. However, in particular, in an organic EL device including an oxide semiconductor, since the oxide semiconductor is degraded by hydrogen, it is desirable to reduce the hydrogen contained in the silicon nitride film as a sealing film. First, referring to Figure 1 , the structure of the organic EL device 200 including the sealing film of the silicon nitride film will be briefly described.

[0040] Figure 1 1 is a schematic cross-sectional view showing an example of an organic EL device 200 according to an embodiment. The organic EL device 200 includes a light-emitting element driving circuit layer 110, an anode 120, a hole injection layer 130, a hole transport layer 114, an organic light-emitting layer 115, a storage body 160, an electron transport layer 116, an electron injection layer 180, a cathode 190, and a sealing film 220. The cathode 190 and the sealing film 220 are transparent films.

[0041] The light emitting element driving circuit layer 110 includes a plate 140 , transistor elements 150 ( 150A, 150B) disposed on the plate 140 , and a planarization film 157 disposed on the plate 140 so as to cover the transistor elements 150 .

[0042] The plate 140 may be, for example, a glass plate or a flexible plate formed of resin. The transistor element 150 disposed on the plate 140 is a thin film transistor (TFT). The transistor element 150 includes: a source / drain electrode 151, a semiconductor layer 152 formed in contact with the source / drain electrode 151, a gate insulating film 153 formed on the semiconductor layer 152, and a gate electrode 154 disposed on the gate insulating film 153. The two transistor elements 150 (150A and 150B) are electrically connected to each other by wiring 155. According to this structure, the organic EL device 200 has an active matrix structure. The semiconductor layer 152 is composed of an oxide semiconductor such as indium gallium zinc oxide (IGZO (InGaZnO)), indium tin zinc oxide (ITZO), zinc oxide (ZnO), indium zinc oxide (IZO), indium gallium oxide (IGO), indium tin oxide (ITO) or indium oxide (InO) containing indium, gallium and zinc.

[0043] The planarization film 157 is disposed on the board 140 so as to cover the transistor element 150. The planarization film 157 makes the surface of the light emitting element driving circuit layer 110 flat.

[0044] The organic EL device 200 has a top emission structure, and when a voltage is applied between the anode 120 and the cathode 190, light is generated in the organic light-emitting layer 115, and the light 170 is emitted outward (upward) through the cathode 190 and the sealing film 220. In addition, among the light generated in the organic light-emitting layer 115, the light toward the light-emitting element driving circuit layer 110 is reflected by the anode 120, and is emitted outward (upward) as the light 170 through the cathode 190 and the sealing film 220.

[0045] The anode 120 is stacked on the surface of the light emitting element driving circuit layer 110, and is a pixel electrode that applies a positive voltage to the cathode 190 to the organic EL device 200. The hole injection layer 130 is arranged on the anode 120. The hole transport layer 114 is arranged on the hole injection layer 130. The organic light emitting layer 115 is arranged on the hole transport layer 114. Furthermore, the electron transport layer 116 is arranged on the organic light emitting layer 115. The electron injection layer 180 is arranged on the electron transport layer 116. The cathode 190 is arranged on the electron injection layer 180. Among them, the hole transport layer 114 and the electron transport layer 116 are sometimes omitted depending on the performance of the hole injection layer 130, the electron injection layer 180, and the organic light emitting layer 115 as the adjacent layers.

[0046] The anode 120 , the hole injection layer 130 , the hole transport layer 114 , the organic light emitting layer 115 , the electron transport layer 116 , the electron injection layer 180 , and the cathode 190 are examples of light emitting elements, and the transistor element 150 is an example of a driving element including an oxide semiconductor.

[0047] The sealing film 220 is used as a protective film to block moisture from penetrating from the outside into the organic EL device 200. The sealing film 220 is an example of a sealing film for sealing a light emitting element formed on the surface of a substrate and a driving element including an oxide semiconductor for driving the light emitting element.

[0048] The organic EL device 200 is not tolerant to moisture. If moisture is doped into the organic EL device 200 from the outside, the organic EL device 200 deteriorates. In addition, the oxide semiconductor contained in the transistor element 150 deteriorates due to the doping of hydrogen. Therefore, in the process of forming the sealing film 220, in order to reduce hydrogen (H2) and moisture (H2O), it is considered to use SiF4 gas and N2 gas that do not contain hydrogen atoms to form a silicon nitride film. Thus, the hydrogen concentration in the sealing film 220 in the manufacturing process of the organic EL device 200 is reduced, so that the degradation of the characteristics of the sealing film 220 and the deterioration of the reliability of the organic EL device 200 can be suppressed.

[0049] In the process of forming the sealing film 220, if the temperature of the substrate is controlled to be higher than 200°C, the stability and other characteristics of the film will be improved, but it will have an adverse effect on the organic EL device 200 with low heat resistance. Therefore, the silicon nitride film must be formed in a state where the temperature of the substrate is controlled to be 200°C or less, preferably 100°C or less.

[0050] Therefore, when the temperature of the substrate is controlled to be below 200°C, preferably below 100°C, and a silicon nitride film is formed by CVD (Chemical Vapor Deposition) method using SiF4 gas and N2 gas, the film quality is poor and an unstable film will be formed. An unstable film refers to, for example, when a large amount of fluorine remains in the formed silicon nitride film, the fluorine in the film reacts with moisture in the atmosphere, thereby changing the film quality of the silicon nitride film. When the temperature of the substrate is controlled to be below 200°C and a silicon nitride film is formed, fluorine is likely to remain in the silicon nitride film, and therefore, an unstable film is likely to be formed. On the other hand, as mentioned above, when the temperature of the substrate is controlled to be, for example, above 300°C during the formation of the silicon nitride film, the stability of the film becomes good, but the organic EL device 200 deteriorates due to the heat applied during the manufacturing process.

[0051] In addition, when the temperature of the substrate is controlled below 200°C and a silicon nitride film is formed by CVD using SiF4 gas and N2 gas, the coverage is poor and the silicon nitride film is not easy to adhere to the inclined surface (tapered portion).

[0052] For example, Figure 1 , a plurality of concave portions and convex portions are formed on the surface of a substrate formed with a silicon nitride film, and the side surfaces of at least some of the concave portions or convex portions are configured in a tapered shape like the inclined surface A.

[0053] Therefore, if there is too much fluorine in the silicon nitride film, the coverage of the film on the side surfaces of the concave or convex portion becomes poor, and the silicon nitride film cannot be formed on the inclined surface A, or cracks are introduced into the silicon nitride film on the inclined surface A. As a result, moisture is introduced into the organic EL device 200 from the outside, and the organic EL device 200 is deteriorated.

[0054] From the above, it is desired to form a silicon nitride film used as the sealing film 220 in an environment where the temperature of the substrate is 200° C. or less, to form a film with good coverage and film stability, and to prevent degradation of the organic EL device 200. Therefore, in the film forming method of this embodiment, a film with good coverage and film stability is formed in an environment where the temperature of the substrate is 200° C. or less.

[0055] In the film forming method of the present embodiment, film formation is performed in an ALD (Atomic Layer Deposition) manner. That is, SiF4 gas is initially supplied to allow the SiF4 gas to adhere to the surface of the substrate, and then the SiF4 gas is stopped and the residual gas of the SiF4 gas is exhausted. Next, N2 gas and high-frequency power are supplied to generate N2 gas plasma, and the SiF4 gas attached to the surface of the substrate is nitrided by the N2 gas plasma, thereby forming a silicon nitride film. The temperature of the substrate during film formation is controlled to be below 200°C, preferably below 100°C. According to the film forming method of the present embodiment, during Figure 1 A silicon nitride film can be formed with good coverage in tapered portions such as the inclined surface A. In addition, a stable silicon nitride film with good film quality can be formed in an environment where the temperature of the substrate during film formation is controlled to be 200° C. or less.

[0056] An example of a film forming apparatus for executing the film forming method of this embodiment will be described below with reference to Figure 2 After describing the film forming method and its effect of this embodiment, refer to Figure 3 to Figure 5 While explaining in detail.

[0057] [Film forming device]

[0058] Figure 2The cross-sectional schematic diagram shows an example of a film forming apparatus 100 for performing a film forming method according to an embodiment. The film forming apparatus 100 is an inductively coupled plasma (ICP) processing apparatus for performing various substrate processing methods on a rectangular substrate (hereinafter referred to as a "substrate") G for FPD in a top view. The film forming apparatus 100 is an example of a film forming apparatus for performing a film forming method according to an embodiment, but is not limited thereto.

[0059] As the material of the substrate, glass is mainly used, and transparent synthetic resins are sometimes used depending on the purpose. Here, the substrate processing includes film forming processing and etching processing. As an FPD, a liquid crystal display (Liquid Crystal Display: LCD) can be exemplified. It can be electroluminescence (Electro Luminescence: EL), plasma display panel (Plasma Display Panel; PDP), etc. The substrate G has a circuit pattern of the light-emitting element and driving element of the organic EL device 200 formed on its surface. In addition, the plane size of the substrate for FPD has been mass-produced with the passage of time. The plane size of the substrate G processed by the film forming device 100, for example, at least includes a size ranging from about 1500mm×1800mm of the 6th generation to about 3000mm×3400mm of the 10.5th generation. In addition, the thickness of the substrate G is about 0.2mm to several mm.

[0060] The film forming apparatus 100 includes a rectangular parallelepiped box-shaped processing chamber 10 , a substrate mounting table 60 disposed in the processing chamber 10 and having a rectangular outer shape in a plan view on which a substrate G is mounted, and a control unit 90 .

[0061] The processing chamber 10 is divided into two spaces, upper and lower, by a dielectric plate 11. The antenna room as the upper space is formed by the upper chamber 12, and the processing chamber S as the lower space is formed by the lower chamber 13. The processing chamber 10 is formed of metal such as aluminum, and the dielectric plate 11 is formed of ceramics such as alumina (Al2O3) or quartz. The dielectric plate 11 is an example of a window member of the inductively coupled plasma device, and the window member can be composed of a plurality of metal plates instead of the dielectric plate.

[0062] In the processing chamber 10, a rectangular ring-shaped support frame 14 is disposed at a position that becomes a boundary between the lower chamber 13 and the upper chamber 12 so as to protrude into the processing chamber 10, and a dielectric plate 11 is placed on the support frame 14. The processing chamber 10 is grounded by a ground wire.

[0063] A loading / unloading port 13b for loading / unloading the substrate G into / out of the lower chamber 13 is provided on the side wall 13a of the lower chamber 13, and the loading / unloading port 13b is openable and closed by a gate valve 20. The lower chamber 13 is adjacent to a conveying chamber (not shown) containing a conveying mechanism, and the gate valve 20 is opened and closed to allow the conveying mechanism to load / unload the substrate G via the loading / unloading port 13b.

[0064] In addition, a plurality of exhaust ports 13f are provided on the bottom plate 13d of the lower chamber 13. The exhaust ports 13f are connected to a gas exhaust pipe 51, and the gas exhaust pipe 51 is connected to an exhaust device 53 via a pressure control valve 52. The gas exhaust pipe 51, the pressure control valve 52, and the exhaust device 53 form a gas exhaust section 50. The exhaust device 53 has a vacuum pump such as a turbomolecular pump, and the lower chamber 13 can be freely evacuated to a predetermined vacuum degree during the process.

[0065] A support beam for supporting the dielectric plate 11 is provided on the lower surface of the dielectric plate 11, and the support beam also serves as a shower head 30. The shower head 30 is formed of a metal such as aluminum, and a surface treatment based on anodization can be performed. A gas flow path 31 extending in the horizontal direction is formed in the shower head 30. The gas flow path 31 is connected to a gas discharge hole 32 extending downward and located below the shower head 30 and facing the processing chamber S.

[0066] A gas introduction pipe 45 connected to the gas flow path 31 is connected to the upper surface of the dielectric plate 11. The gas introduction pipe 45 airtightly penetrates the supply port 12b opened at the top 12a of the upper chamber 12, and is connected to the processing gas supply unit 40 via a gas supply pipe 41 airtightly combined with the gas introduction pipe 45. The processing gas supply unit 40 is formed by the gas introduction pipe 45, the gas supply pipe 41, valves 42a, 42b, flow controllers 43a, 43b, SiF4 gas supply source 44a, and N2 gas supply source 44b. The SiF4 gas and N2 gas supplied from the processing gas supply unit 40 are supplied to the shower head 30 via the gas supply pipe 41 and the gas introduction pipe 45, and are discharged to the processing chamber S via the gas flow path 31 and the gas discharge hole 32. It should be noted that when a metal plate is used instead of the dielectric plate 11, a gas discharge hole can be provided in the metal plate to serve as a shower head.

[0067] A high frequency antenna 15 is disposed in the upper chamber 12 forming the antenna chamber. The high frequency antenna 15 is formed by winding an antenna line 15a formed of a conductive metal such as copper in a loop or spiral shape. For example, multiple loop-shaped antenna lines 15a may be disposed.

[0068] The terminal of the antenna line 15a is connected to a power supply member 16 extending upward from the upper chamber 12, and the upper end of the power supply member 16 is connected to a power supply line 17, and the power supply line 17 is connected to a high-frequency power supply 19 via a matching device 18 for impedance matching. A high-frequency power of, for example, 13.56 MHz is applied to the high-frequency antenna 15 from the high-frequency power supply 19, thereby forming an induced electric field in the lower chamber 13. Through this induced electric field, the processing gas supplied from the shower head 30 to the processing chamber S is plasmatized, and an inductively coupled plasma is generated, and ions, neutral radicals, etc. in the plasma are provided to the substrate G. The high-frequency power supply 19 is a source source for plasma generation, and the high-frequency power supply 73 connected to the substrate mounting table 60 attracts the generated ions and becomes a bias source that imparts kinetic energy. In this way, the ion source generates plasma by inductive coupling, and the bias source as another power source is connected to the substrate mounting table 60 to control the ion energy. In this way, the generation of plasma and the control of ion energy are independently performed, which can improve the degree of freedom of the process. The processing gas supply unit 40 and the high frequency power supply 19 are an example of a plasma generating unit that converts the gas into plasma and generates plasma in the chamber.

[0069] The substrate mounting table 60 has a substrate 63 and an electrostatic chuck 66 formed on the upper surface 63a of the substrate 63. The top view shape of the substrate 63 is rectangular, and has a plane size equal to that of the substrate G mounted on the substrate mounting table 60. The length of the long side can be set to about 1800mm to 3400mm, and the length of the short side can be set to about 1500mm to 3000mm. For this plane size, the thickness of the substrate 63 can be, for example, about 50mm to 100mm. The substrate 63 is formed of stainless steel, aluminum, aluminum alloy, etc. On the substrate 63, a serpentine temperature regulating medium flow path 62a is provided in a manner covering the entire area of ​​the rectangular plane. It should be noted that the temperature regulating medium flow path 62a can be provided on the electrostatic chuck 66, for example.

[0070] At both ends of the temperature regulating medium flow path 62a, there are connected: a delivery pipe 62b for supplying the temperature regulating medium to the temperature regulating medium flow path 62a, and a return pipe 62c for discharging the temperature regulating medium that is heated by circulating the temperature regulating medium flow path 62a. The delivery pipe 62b and the return pipe 62c are respectively connected to the delivery flow path 82 and the return flow path 83, and the delivery flow path 82 and the return flow path 83 are connected to the cooler unit 81 arranged in the external space E. The cooler unit 81 has: a main body for controlling the temperature and discharge flow rate of the temperature regulating medium, and a pump for pumping the temperature regulating medium (both are not shown in the figure). It should be noted that a refrigerant is used as the temperature regulating medium. The temperature regulating form is a form in which the temperature regulating medium is circulated in the substrate 63, but it can be a form in which a heater is built into the substrate 63 and the temperature is regulated by the heater, or it can be a form in which the temperature regulating medium and the heater are both used to regulate the temperature. In addition, instead of the heater, temperature regulation accompanied by heating can be performed by circulating a high-temperature temperature regulating medium.

[0071] A box-shaped susceptor 68 formed of an insulating material and having a step portion inside is fixed to the bottom plate 13d of the lower chamber 13, and a substrate mounting table 60 is mounted on the step portion of the susceptor 68. An electrostatic chuck 66 is formed on the upper surface of the substrate 63 to directly mount the substrate G. The electrostatic chuck 66 includes a ceramic layer 64, which is a dielectric coating formed by thermally spraying ceramics such as alumina, and an adsorption electrode 65, which is a conductive layer embedded in the ceramic layer 64 and has an electrostatic adsorption function. The adsorption electrode 65 is connected to a DC power supply 75 via a power supply line 74 and a switch 76. When the switch 76 is turned on by the control unit 90, a DC voltage is applied from the DC power supply 75 to the adsorption electrode 65 to generate a Coulomb force. By this Coulomb force, the substrate G is electrostatically adsorbed to the electrostatic chuck 66 and is held in a state of being mounted on the upper surface of the substrate 63. When the switch 76 is closed and the switch 77 interposed on the ground line branched from the power supply line 74 is opened, the charge accumulated in the adsorption electrode 65 flows to the ground.

[0072] A temperature sensor such as a thermocouple is provided on the substrate 63, and the monitor information based on the temperature sensor is transmitted to the control unit 90 at any time. The control unit 90 performs temperature control of the substrate 63 and the substrate G based on the transmitted temperature monitor information. More specifically, the temperature and flow rate of the temperature control medium supplied from the cooler unit 81 to the conveying flow path 82 are adjusted by the control unit 90. Then, the temperature control medium with temperature adjustment and flow adjustment circulates in the temperature control medium flow path 62a, thereby performing temperature control of the substrate mounting table 60. It should be noted that a temperature sensor such as a thermocouple can be provided on, for example, the electrostatic chuck 66.

[0073] A rectangular frame-shaped focus ring 69 is placed on the upper surface of the base 68, which is the outer periphery of the electrostatic chuck 66, and is set so that the upper surface of the focus ring 69 is lower than the upper surface of the electrostatic chuck 66. The focus ring 69 is made of ceramics such as alumina or quartz.

[0074] The lower surface of the substrate 63 is connected to the power supply member 70. The lower end of the power supply member 70 is connected to the power supply line 71, and the power supply line 71 is connected to the high-frequency power supply 73 as a bias source via a matching device 72 for impedance matching. The high-frequency power supply 73 applies a high-frequency power of, for example, 3.2 MHz to the substrate stage 60, so that the substrate stage 60 functions as a lower electrode, and ions generated in the high-frequency power supply 19 as a source source for plasma generation can be attracted to the substrate G.

[0075] A plurality of, for example, twelve lift pins 78 are provided inside the substrate stage 60 to lift the substrate G in order to exchange the substrate G with a transfer arm (not shown) outside the processing chamber 10 . Figure 1 In the figure, two lifting pins 78 are shown in simplified form. The plurality of lifting pins 78 penetrate the substrate mounting table 60 and move up and down by the power of the motor transmitted through the connecting member. A bottom bellows (not shown) is provided on the through hole of the lifting pin 78 that penetrates the outside of the processing container to maintain the airtightness between the vacuum side and the atmosphere side in the processing container.

[0076] The control unit 90 is used to control the operation of each component of the film forming device 100, such as the cooler unit 81, the high-frequency power supply 19, 73, the direct current power supply 75, the processing gas supply unit 40, the gas exhaust unit 50, etc. The control unit 90 has a CPU (Central Processing Unit) and a memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The CPU performs a prescribed process according to a process program (process process program) stored in a storage area of ​​the memory. In the process program, control information of the process conditions of the film forming device 100 is set. The control information includes, for example, gas flow rate, pressure in the processing chamber 10, temperature in the processing chamber 10, temperature of the substrate 63, process time, etc.

[0077] The process program and program used by the control unit 90 can be stored in a hard disk, an optical disk, a magneto-optical disk, etc. In addition, the process program etc. can be stored in a storage medium such as a CD-ROM, a DVD, a memory card, etc. that can be read by a portable computer and installed in the control unit 90. The control unit 90 also has a user interface such as an input device such as a keyboard and a mouse for inputting commands, a display device such as a display that visually displays the operating status of the film forming device 100, and an output device such as a printer.

[0078] [Film Forming Method]

[0079] Next, use Figure 3 and Figure 4 ,right Figure 2 The film forming method of this embodiment performed in the film forming apparatus 100 is described. Figure 3 This is a flowchart showing an example of a film forming method according to an embodiment. Figure 4 This is a timing chart showing an example of a film forming method according to an embodiment. Figure 2 Valves 42a, 42b.

[0080] first, Figure 3 In step S1, a substrate W is placed on the substrate stage 60 and prepared. The substrate W is transported from the loading / unloading port 13b to the processing chamber 10 by, for example, opening and closing the gate valve 20, and is placed on the substrate stage 60. Next, Figure 3 In step S2, the temperature control medium at a desired temperature is circulated in the temperature control medium flow path 62a of the substrate mounting table 60 from the cooler unit 81 to control the temperature of the substrate to a predetermined temperature of 100° C. or less. In addition, the pressure in the processing chamber 10 is reduced to a predetermined vacuum degree.

[0081] Next, in the processing gas supply unit 40, Figure 3 In step S3, open Figure 2 The valve 42a is closed, and SiF4 gas, which is an example of silicon halide gas, is supplied from the SiF4 gas supply source 44a to the processing chamber 10 via the gas introduction pipe 45. Figure 4 In the first cycle of supply of SiF 4 gas, SiF 4 gas molecules adhere to the surface of the substrate.

[0082] After a predetermined time (e.g., 10 seconds) has passed since the valve 42a was opened, Figure 3 In step S4, the residual gas of SiF4 gas is removed for another predetermined time (e.g., 10 seconds). At this time, close Figure 2 Valve 42a is opened to stop the supply of SiF4 gas from SiF4 gas supply source 44a. Thus, SiF4 gas is exhausted from processing chamber 10, and the residual gas of SiF4 gas is removed. The above is a supply step of raw material gas for forming a silicon nitride film (hereinafter referred to as "step A"). During the execution of step S4, inert gas such as Ar gas and He gas can be supplied into processing chamber 10. Thus, SiF4 gas is exhausted from processing chamber 10 by inert gas, and the residual gas of SiF4 gas is removed. It should be noted that the prescribed time for opening valve 42a and the prescribed time for removing the residual gas of SiF4 gas can be set to the same time or to different times.

[0083] then, Figure 3 In step S5, the processing gas supply unit 40 supplies N2 gas as an example of nitrogen-containing gas. Figure 3 In step S6, high frequency power (RF (Radio Frequency) power) is applied from the high frequency power supply 19. The timing of applying the high frequency power may be after the timing of supplying the N2 gas, or may be at the same time as the timing of supplying the N2 gas. Thus, the start Figure 4 The supply of N2 gas of the first cycle is started, and the supply of RF power is started, and the N2 gas is ionized by the high frequency power to generate N2 gas plasma. By the N2 gas plasma, the SiF4 gas molecules attached to the surface of the substrate are ionized by the high frequency power into atoms containing Si and F, and similarly react with the ionized N atoms to form a silicon nitride film.

[0084] After a predetermined time (e.g., 10 seconds) has passed since the valve 42b was opened, Figure 3 In step S7, the residual gas of N2 gas is removed for another predetermined time (e.g., 10 seconds). At this time, close Figure 2 Valve 42b is closed to stop the supply of N2 gas from N2 gas supply source 44b. In addition, the application of high-frequency power is stopped. The above is a step of supplying reaction gas for forming a silicon nitride film (hereinafter referred to as "step B"). During the execution of step S7, an inert gas can be supplied to the processing chamber 10. Thus, the N2 gas is exhausted from the processing chamber 10 by the inert gas, and the residual gas of the N2 gas is removed. It should be noted that the prescribed time for opening valve 42b and the prescribed time for removing the residual gas of the N2 gas can be set to the same time or to different times.

[0085] then, Figure 3 In step S8, whether the silicon nitride film reaches a predetermined film thickness is determined by determining whether to repeat steps A and B for a predetermined X number of times. The film thickness of the silicon nitride film corresponds to the number of executions of steps A and B. When steps A and B are repeated X times, the silicon nitride film reaches a predetermined film thickness. In other words, the number of repetitions of steps A and B corresponding to the predetermined film thickness reached by the silicon nitride film is X times. X is an integer greater than 1. In step S8, steps A and B are repeated until it is determined that they have been executed X times. Thus, if Figure 4 As shown, steps (A, B) of the 2nd cycle, steps (A, B) of the 3rd cycle, ..., steps (A, B) of the Xth cycle are performed sequentially. Figure 3 In step S8, when it is determined that step (A, B) has been executed X times, the process proceeds to step S9, the substrate is unloaded, and the process ends.

[0086] It should be noted that the number of repetitions X may be preset, or, for example, the thickness of the silicon nitride film may be optically measured in real time and the number of repetitions X may be set in real time based on the measurement result.

[0087] An example of the evaluation of the characteristics of the silicon nitride film by the film forming method of the present embodiment described above is shown in FIG. Figure 5 , and the description will be given while comparing with the comparative example. Figure 5 It is a diagram showing an example of the evaluation of the characteristics of the silicon nitride film by the film forming methods according to the embodiment and the comparative example.

[0088] like Figure 5 As shown, the film forming method of this embodiment forms the film by ALD method, while the film forming method of the comparative example forms the film by CVD method. In addition, in the film forming method of this embodiment, the temperature of the substrate during film forming is controlled to 100° C. and 200° C., while in the comparative example, the temperature of the substrate during film forming is controlled to 100° C. In addition, SiF4 gas and N2 gas are used in both.

[0089] As a result, the tapered portion ( Figure 1 The coverage of the inclined surface A) is b / a( Figure 5 The ratio of the film thickness b of the tapered portion shown in the figure to the film thickness a of the upper portion of the silicon nitride film) is basically 0 in the comparative example (that is, a state in which no silicon nitride film is formed in the tapered portion). In contrast, it can be seen that in the film forming method of the present embodiment, when the temperature of the substrate is 100°C, b / a is "0.37", and a silicon nitride film can also be formed in the tapered portion. In addition, when the temperature of the substrate is 200°C, b / a is "0.47". That is, in the film forming method of the present embodiment, a film is formed in the tapered portion by the ALD method based on the process conditions shown above, so that a silicon nitride film with good coverage can be formed. It should be noted that in the case of the comparative example, the cone angle θ is 73°, and in the case of the present embodiment, when the temperature of the substrate is 100°C, the cone angle θ is 72°, and when the temperature of the substrate is 200°C, the cone angle θ is 77°, and the cone angles are equal.

[0090] Furthermore, the refractive index (RI) of the silicon nitride film, which is an indicator of film quality, is "1.79" in the case of the comparative example, and is "1.91" in the case of the present embodiment when the substrate temperature is 100°C. When the refractive index RI of the film is 1.9 to 2.0, it can be evaluated that the film quality is good. It can be seen that the film forming method of the present embodiment can form a silicon nitride film with better film quality than the film forming method based on the CVD method of the comparative example.

[0091] As described above, according to the film forming method of this embodiment, the temperature of the substrate during film forming is controlled to be below 200° C., preferably below 100° C. Furthermore, by repeating the ALD method of supplying a gas containing a silicon halide gas → exhausting → supplying a nitrogen-containing gas → exhausting X times, a sealing film of a silicon nitride film is formed on the light-emitting element of the organic EL device 200.

[0092] According to the film forming method, a silicon nitride film with good coverage and good film quality can be formed on a tapered portion such as the inclined surface A on a light-emitting element. In addition, in an environment where the temperature of the substrate during film formation is controlled to a low temperature of 200°C or less, the coverage is also good, and a silicon nitride film with good film quality characteristics can be formed. In the process of forming a sealing film of a silicon nitride film on a light-emitting element with low heat resistance, according to the film forming method of this embodiment, a silicon nitride film with good coverage and good film quality can also be formed when the temperature of the substrate is controlled to 100°C or less.

[0093] It should be noted that various changes are considered for the gas used in the film forming method of this embodiment. For example, the silicon halogenated gas contained in the gas containing silicon halogenated gas is not limited to silicon tetrafluoride gas (SiF4). The gas containing silicon halogenated gas may include at least one of silicon tetrafluoride gas (SiF4), silicon tetrachloride gas (SiCl4), disilicon hexafluoride gas (Si2F6), and disilicon hexachloride gas (Si2Cl6).

[0094] In addition, the nitrogen-containing gas is not limited to nitrogen (N2). The nitrogen-containing gas may include at least one of nitrogen (N2) and ammonia (NH3).

[0095] Furthermore, H2 gas may be added to the nitrogen-containing gas, or a rare gas such as He gas or Ar gas may be added. By adding H2 gas, the coverage of the silicon nitride film can be improved.

[0096] However, the concentration of the added H2 gas is preferably adjusted so that the hydrogen concentration in the silicon nitride film becomes 15% or less. This is because the hydrogen from the H2 gas combines with the fluorine remaining in the silicon nitride film in excess to remove the fluorine, which can suppress the degradation of the film quality of the silicon nitride film based on fluorine. However, if the amount of H2 gas is increased excessively, even if the fluorine is removed, hydrogen that is not combined with fluorine will remain, and there is a concern that the light-emitting element formed on the surface of the substrate and the driving element including an oxide semiconductor that drives the light-emitting element will degrade due to hydrogen.

[0097] As described above, according to the silicon nitride film forming method and film forming apparatus of the present embodiment, a silicon nitride film with good coverage can be formed even in an environment where the substrate temperature is 200° C. or less.

[0098] The film forming method and film forming apparatus of the silicon nitride film of the embodiment disclosed this time are examples in all aspects and should be considered as non-limiting. The embodiment can be deformed and improved in various ways without departing from the attached claims and their gist. The features described in the above-mentioned multiple embodiments can also take other configurations within the scope of non-contradiction, and can be combined within the scope of non-contradiction.

[0099] The film forming device disclosed in the present invention can also be used for any type of device such as Atomic Layer Deposition (ALD) device, 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 method for forming a silicon nitride film, the method comprising forming a silicon nitride film on a substrate in a processing chamber accommodated in a processing chamber, The processing chamber has: A mounting table, used for mounting the substrate; A high frequency antenna, which is disposed above the mounting platform and is used to form an inductively coupled plasma; A shower head is arranged between the mounting platform and the high frequency antenna. The film forming method comprises the following steps: Step (a), supplying a gas containing silicon halide gas from the shower head into the processing chamber without supplying high frequency power to the high frequency antenna; Step (b), after the step (a), stopping the supply of the gas containing the silicon halide gas, exhausting and depressurizing the processing chamber; Step (c), supplying a nitrogen-containing gas into the processing chamber after the step (b); Step (d), after the step (c), supplying the high frequency power to the high frequency antenna to generate the inductively coupled plasma in the processing chamber; Step (e), after the step (d), stopping the supply of the nitrogen-containing gas and the supply of the high-frequency power, exhausting and depressurizing the interior of the processing chamber; and, Repeating the steps (a) to (e) X times in the same processing chamber of the processing chamber until the silicon nitride film having a predetermined film thickness is formed, wherein X ≥ 1, In the steps (a) to (e), the temperature of the substrate is controlled to be 100° C. or less.

2. The method for forming a silicon nitride film according to claim 1, wherein: The gas containing silicon halide gas includes at least any one of silicon tetrafluoride gas (SiF4), silicon tetrachloride gas (SiCl4), disilicon hexafluoride gas (Si2F6), and disilicon hexachloride gas (Si2Cl6).

3. The method for forming a silicon nitride film according to claim 1, wherein: The nitrogen-containing gas includes at least one of nitrogen (N 2 ) and ammonia (NH 3 ).

4. The method for forming a silicon nitride film according to claim 1 or 2, wherein: A plurality of concave portions and convex portions are formed on the surface of the substrate, at least a part of the side surfaces of the concave portions or the convex portions are constituted by inclined surfaces, and the silicon nitride film is formed at least on the inclined surfaces.

5. The method for forming a silicon nitride film according to claim 1 or 2, wherein: A layer including an oxide semiconductor is formed on the surface of the substrate.

6. The method for forming a silicon nitride film according to claim 5, wherein: The silicon nitride film is a sealing film for sealing a light emitting element formed on the surface of the substrate and a driving element including the oxide semiconductor for driving the light emitting element.

7. The method for forming a silicon nitride film according to claim 1 or 2, wherein: A predetermined concentration of H 2 gas and / or a rare gas is added to the nitrogen-containing gas.

8. A film forming device for forming a silicon nitride film on a substrate in a processing chamber accommodated in a processing chamber, comprising the processing chamber and a control unit, The processing chamber has: A mounting table, used for mounting the substrate; A high frequency antenna, which is disposed above the mounting platform and is used to form an inductively coupled plasma; A shower head is arranged between the mounting platform and the high frequency antenna. The control unit is used to control the following processes: Step (a), supplying a gas containing silicon halide gas from the shower head into the processing chamber without supplying high frequency power to the high frequency antenna; Step (b), after the step (a), stopping the supply of the gas containing the silicon halide gas, exhausting and depressurizing the processing chamber; Step (c), after the step (b), supplying nitrogen-containing gas from the shower head into the processing chamber; Step (d), after step (c), supplying the high frequency power to the high frequency antenna to generate inductively coupled plasma in the processing chamber; Step (e), after the step (d), stopping the supply of the nitrogen-containing gas and the supply of the high-frequency power, exhausting and depressurizing the interior of the processing chamber; and, Repeating the steps (a) to (e) X times in the same processing chamber of the processing chamber until the silicon nitride film having a predetermined film thickness is formed, wherein X ≥ 1, Furthermore, in the steps (a) to (e), the temperature of the substrate is controlled to be 100° C. or lower.

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