CN103403847A - Silicon nitride film deposition method, organic electronic device manufacturing method, and silicon nitride film deposition device - Google Patents

Abstract

The present invention provides a method of forming a silicon nitride film for forming a silicon nitride film on a substrate accommodated in a processing container, wherein a processing gas containing silane-based gas, nitrogen gas, and hydrogen gas is supplied into the processing container, and the above-mentioned processing The gas is excited to generate plasma, and plasma processing using the plasma is performed to form a silicon nitride film on the substrate. The aforementioned silicon nitride film is used as a sealing film for organic electronic devices. In the plasma processing using the plasma, the pressure in the processing container is maintained at 20 Pa to 60 Pa.

Description

Film-forming method of silicon nitride film, method of manufacturing organic electronic device, and film-forming apparatus of silicon nitride film

technical field

The present invention relates to a method for forming a silicon nitride film, a method for manufacturing an organic electronic device, and a device for forming a silicon nitride film.

Background technique

In recent years, organic EL elements using organic electroluminescence (EL: Electro Luminescence), which are light-emitting devices including organic layers, are being developed. Since organic EL elements are self-illuminating, they consume less power and have advantages such as superior viewing angles compared with liquid crystal displays (LCDs), etc., and future development is expected.

The most basic structure of this organic EL element is a laminated structure (sandwich structure) in which a positive electrode (anode) layer, a light-emitting layer, and a negative electrode (cathode) layer are laminated on a glass substrate. Among them, the light-emitting layer is weak against water and oxygen, and when water or oxygen is mixed, its characteristics change, resulting in non-luminous spots (dark spots), which is one of the causes of shortening the life of organic EL elements. Therefore, in the manufacture of organic electronic devices, organic elements are sealed so that external water and oxygen do not pass through the device. That is, in the manufacture of an organic electronic device, a positive electrode layer, a light-emitting layer, and a negative electrode layer are sequentially formed on a glass substrate, and a sealing film (sealing film) layer is further formed.

As the sealing film, for example, a silicon nitride film (SiN film) can be used. The silicon nitride film is formed, for example, by plasma CVD (Chemical Vapor Deposition). Specifically, for example, a source gas including silane (SiH ₄ ) gas and nitrogen (N ₂ ) gas is excited by microwave power to generate plasma, and a silicon nitride film is formed using the generated plasma. In addition, the organic EL element has a problem of being damaged when the temperature of the glass substrate reaches a high temperature of 100° C. or higher, so the silicon nitride film is formed in a low temperature environment of 100° C. or lower (Patent Document 1).

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2010-219112

Contents of the invention

The problem to be solved by the invention

However, in the case of using the method described in Patent Document 1, since the silicon nitride film is formed in a low-temperature environment, the film characteristics of the silicon nitride film may decrease. Specifically, for example, the silicon nitride film may have low step coverage (step coverage) and film quality (for example, density related to the wet etching rate of hydrofluoric acid), and the silicon nitride film may have low film stress (film stress) is inappropriate.

In addition, in the above, the case where a silicon nitride film is formed on a glass substrate as a sealing film for an organic electronic device has been described, but this problem may arise when a silicon nitride film is formed for applications other than a sealing film for an organic electronic device. also exist. That is, when the temperature of the substrate is, for example, 100° C. or lower, when the silicon nitride film is formed on the substrate, the film quality of the silicon nitride film may decrease as described above.

The present invention was made in view of the above circumstances, and an object of the present invention is to properly form a silicon nitride film on a substrate in a low-temperature environment where the temperature of the substrate is 100° C. or lower, and to improve the film characteristics of the silicon nitride film.

Technical solutions for solving problems

In order to achieve the above object, according to an aspect of the present invention, it is a film forming method of a silicon nitride film, which is a film forming method of forming a silicon nitride film on a substrate accommodated in a processing container. A processing gas containing silane-based gas, nitrogen gas, and hydrogen gas is excited to generate plasma, and plasma processing using the plasma is performed to form a silicon nitride film on the substrate.

As a result of intensive research by the inventors, it was found that when a silicon nitride film is formed on a substrate by a plasma film forming method, when a processing gas containing silane-based gas, nitrogen gas, and hydrogen gas is used, the The etch characteristics of the wet etch rate are improved. Specifically, by adding hydrogen gas to the process gas, the wet etching rate is reduced and the step coverage of the silicon nitride film is improved. In addition, when the amount of hydrogen added to the process gas is increased, the film stress of the silicon nitride film becomes negative. That is, it can be seen that the film stress of the silicon nitride film can be appropriately controlled. Therefore, according to the present invention, even if the temperature of the substrate in the processing container is in a low-temperature environment such as 100° C. or lower, the controllability of the silicon nitride film formed on the substrate can be improved. In addition, by adding hydrogen gas to the processing gas in this way, the controllability of the film properties is improved, which will be described in detail later.

According to another aspect of the present invention, it is a method of manufacturing an organic electronic device. An organic element is formed on a substrate, and then, a processing gas containing a silane gas, nitrogen gas, and hydrogen gas is supplied to a processing container containing the substrate, so that The process gas is excited to generate plasma, and a plasma process using the plasma is performed to form a silicon nitride film as a sealing film so as to cover the organic element.

In addition, according to another aspect of the present invention, there is provided a silicon nitride film forming apparatus for forming a silicon nitride film on a substrate, comprising: a processing container for accommodating and processing a substrate; a processing gas supply unit for processing gas including silane-based gas, nitrogen gas, and hydrogen gas; a plasma excitation unit that excites the processing gas to generate plasma; and a control unit that controls the processing gas supply unit and the plasma excitation unit, A silicon nitride film is formed on the substrate by performing the plasma treatment using the aforementioned plasma.

The effect of the invention

According to the present invention, the silicon nitride film is appropriately formed on the substrate in a low-temperature environment where the temperature of the substrate is 100° C. or lower, and the controllability of the film characteristics of the silicon nitride film can be improved.

Description of drawings

FIG. 1 is an explanatory diagram showing a schematic configuration of a substrate processing system for carrying out the method for manufacturing an organic EL device according to the present embodiment.

FIG. 2 is an explanatory view showing a manufacturing process of the organic EL device of the present embodiment.

3 is a longitudinal sectional view schematically showing the configuration of a plasma film forming apparatus.

Fig. 4 is a plan view of a raw material gas supply structure.

5 is a plan view of a gas supply structure for plasma excitation.

6 is a graph showing the relationship between the supply flow rate of hydrogen gas and the wet etching rate of a silicon nitride film when the plasma film forming method of this embodiment is used.

7 is a graph showing the relationship between the supply flow rate of hydrogen gas and the film stress of the silicon nitride film when the plasma film forming method of this embodiment is used.

8 is a graph showing the relationship between the microwave power and the film stress of the silicon nitride film when the plasma film forming method of this embodiment is used.

FIG. 9 is a case where a silicon nitride film is formed using a processing gas containing silane gas, nitrogen gas, and hydrogen gas in the manner of the present embodiment, and a silicon nitride film is formed using a processing gas containing silane gas and ammonia gas as in the prior art. An explanatory diagram comparing the case of a silicon film.

Fig. 10 is a plan view of a raw material gas supply structure according to another embodiment.

Fig. 11 is a cross-sectional view of a raw material gas supply pipe according to another embodiment.

Fig. 12 is a cross-sectional view of a raw material gas supply pipe according to another embodiment.

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in this specification and the drawings, the same reference numerals are attached to constituent elements having substantially the same functions, and repeated descriptions are omitted.

First, a method for manufacturing an organic electronic device according to an embodiment of the present invention will be described together with a substrate processing system for implementing the method. FIG. 1 is an explanatory diagram showing a schematic configuration of a substrate processing system 1 . FIG. 2 is an explanatory view showing a manufacturing process of an organic EL device. In addition, in this embodiment mode, the case where an organic EL device is manufactured as an organic electronic device is demonstrated.

As shown in FIG. 1 , a cluster-type substrate processing system 1 has a transfer chamber 10 . The transport chamber 10 has, for example, a substantially polygonal shape (hexagonal in the illustrated example) in plan view, and the inside thereof may be hermetically sealed. Around the transfer chamber 10 , a load lock chamber 11 , a cleaning device 12 , a vapor deposition device 13 , a sputtering device 14 , an etching device 15 , and a plasma film forming device 16 are arranged in this order clockwise in plan view.

A telescopic and rotatable multi-joint transport arm 17 is provided inside the transport chamber 10 . By this transfer arm 17, the glass substrate which is a board|substrate is transferred to the load lock chamber 11 and each processing apparatus 12-16.

The load lock chamber 11 is a vacuum transfer chamber that maintains the inside at a predetermined reduced pressure state in order to transfer a glass substrate transferred from an atmospheric environment (system) to the transfer chamber 10 in a reduced pressure state.

In addition, the configuration of the plasma film forming apparatus 16 will be described later. In addition, general apparatuses may be used for the cleaning apparatus 12 , the vapor deposition apparatus 13 , the sputtering apparatus 14 , and the etching apparatus 15 as other processing apparatuses, and descriptions of their configurations are omitted.

Next, a method of manufacturing an organic EL device performed in the substrate processing system 1 configured as described above will be described.

As shown in FIG. 2( a ), a positive electrode (anode) layer 20 is formed in advance on the upper surface of the glass substrate G. As shown in FIG. The positive electrode layer 20 includes, for example, a transparent conductive material such as indium tin oxide (ITO: Indium Tin Oxide). In addition, the positive electrode layer 20 is formed on the upper surface of the glass substrate G by sputtering or the like, for example.

Then, in the cleaning device 12, after cleaning the surface of the positive electrode layer 20 on the glass substrate G, as shown in FIG. The light emitting layer (organic layer) 21 is formed into a film. Furthermore, the light-emitting layer 21 includes, for example, a multilayer structure in which a hole transport layer, a non-light-emitting layer (electron blocking layer), a blue light-emitting layer, a red light-emitting layer, a green light-emitting layer, and an electron transport layer are stacked.

Next, as shown in FIG. 2( b ), in the sputtering device 14 , a negative electrode (cathode) layer 22 made of, for example, Ag, Al, or the like is formed on the light emitting layer 21 . The negative electrode layer 22 is formed, for example, by depositing target atoms on the light emitting layer 21 through a pattern mask by sputtering. In addition, these positive electrode layer 20, light emitting layer 21, and negative electrode layer 22 constitute the organic EL element of the present invention, and are sometimes simply referred to as "organic EL element" hereinafter.

Next, as shown in FIG. 2( c ), dry etching is performed on the light emitting layer 21 in the etching device 15 using the negative electrode layer 22 as a mask. In this way, the light emitting layer 21 is patterned into a predetermined pattern.

In addition, after the etching of the light-emitting layer 21, the exposed part of the organic EL element and the glass substrate G (positive electrode layer 20) may be cleaned to remove substances adsorbed on the organic EL element, such as organic substances, that is, to perform pre-cleaning. . Furthermore, after precleaning, for example, silylation treatment using a coupling agent may be performed to form a very thin adhesive layer (not shown) on the negative electrode layer 22 . The adhesive layer is firmly bonded to the organic EL element, and the adhesive layer is firmly bonded to the silicon nitride film 23 described later.

Next, as shown in FIG. 2( d ), in the plasma film forming apparatus 16 , for example, silicon nitride as a sealing film is formed so as to cover the light emitting layer 21 , the periphery of the negative electrode layer 22 and the exposed portion of the positive electrode layer 20 . film (SiN film)23. The silicon nitride film 23 is formed by, for example, a microwave plasma CVD method as will be described later.

As described above, in the manufactured organic EL device A, the light emitting layer 21 can emit light by applying a voltage between the positive electrode layer 20 and the negative electrode layer 22 . This organic EL device A can be applied to a display device, a surface light-emitting element (illumination, a light source, etc.), and can be used in various electronic devices in addition.

Next, a film-forming method for forming the above-mentioned silicon nitride film 23 will be described together with the plasma film-forming apparatus 16 for forming the silicon nitride film 23 . FIG. 3 is a longitudinal sectional view schematically showing the configuration of the plasma film forming apparatus 16 . In addition, the plasma film forming apparatus 16 of the present embodiment is a CVD apparatus that generates plasma using a radial line slot antenna.

The plasma film forming apparatus 16 has, for example, a bottomed cylindrical processing container 30 with an open upper surface. The processing container 30 is formed of, for example, an aluminum alloy. In addition, the processing container 30 is grounded. A mounting table 31 as a mounting portion for mounting a glass substrate G, for example, is provided at a substantially central portion of the bottom of the processing container 30 .

The mounting table 31 includes, for example, an electrode plate 32 , and the electrode plate 32 is connected to a DC power supply 33 provided outside the processing container 30 . Electrostatic force is generated on the surface of the mounting table 31 by this DC power supply 33 , and the glass substrate G can be electrostatically adsorbed on the mounting table 31 . In addition, the electrode plate 32 may be connected to, for example, a high-frequency power supply (not shown) for bias voltage.

A dielectric window 41 is provided at the upper opening of the processing container 30 via a seal 40 such as an O-ring for ensuring airtightness. The inside of the processing container 30 is sealed by the dielectric window 41 . On the upper portion of the dielectric window 41, a radial line slot antenna 42 is provided as a plasma excitation unit for supplying microwaves for generating plasma. In addition, aluminum oxide (Al ₂ O ₃ ), for example, can be used for the dielectric window 41 . In this case, the dielectric window 41 has resistance (corrosion resistance) to nitrogen trifluoride (NF ₃ ) gas used in dry cleaning. In addition, in order to further improve the resistance to nitrogen trifluoride, the surface of the alumina of the dielectric window 41 may be covered with diyttrium trioxide (Y ₂ O ₃ ), spinel (MgAl ₂ O ₄ ) or aluminum nitride ( AlN).

The radial line slot antenna 42 includes a substantially cylindrical antenna body 50 whose lower surface is opened. A disk-shaped slit plate 51 having a plurality of slits is provided in an opening on the lower surface of the antenna main body 50 . A dielectric plate 52 formed of a low-loss dielectric material is provided on an upper portion of the slot plate 51 in the antenna main body 50 . A coaxial waveguide 54 passing through a microwave oscillation device 53 is connected to the upper surface of the antenna main body 50 . The microwave oscillation device 53 is provided outside the processing container 30 and is capable of oscillating microwaves of a predetermined frequency, for example, 2.45 GHz, to the radial line slot antenna 42 . With this structure, the microwave oscillated from the microwave oscillator 53 is transmitted into the radial line slot antenna 42, and after being compressed by the dielectric plate 52 to shorten the wavelength, a circularly polarized wave is generated in the slot plate 51, and is transmitted from the dielectric window 41 to the process. The container 30 is irradiated.

Between the mounting table 31 and the radial line slot antenna 42 in the processing container 30 , for example, a substantially flat plate-shaped source gas supply structure (structure) 60 is provided. The external shape of the raw material gas supply structure 60 is formed in the circular shape larger than the diameter of the glass substrate G at least in planar view. The raw material gas supply structure 60 divides the inside of the processing chamber 30 into a plasma generation region R1 on the radial line slot antenna 42 side and a raw material gas dissociation region R2 on the mounting table 31 side. In addition, aluminum oxide can be used for the raw material gas supply structure 60, for example. In this case, since alumina is a ceramic, it has higher heat resistance and higher strength than metal materials such as aluminum. In addition, since the plasma generated in the plasma generation region R1 is not trapped, sufficient ions can be irradiated to the glass substrate. Furthermore, a dense film can be formed by irradiating sufficient ions to the film on the glass substrate. In addition, the source gas supply structure 60 is resistant to nitrogen trifluoride gas used in dry cleaning. Furthermore, in order to improve the resistance to nitrogen trifluoride gas, the surface of the alumina of the raw material gas supply structure 60 may be covered with diyttrium trioxide, spinel, or aluminum nitride.

As shown in FIG. 4 , the raw material gas supply structure 60 is composed of continuous raw material gas supply pipes 61 arranged substantially in a grid on the same plane. The raw material gas supply pipe 61 is formed to have a square longitudinal section when viewed in the axial direction. A plurality of openings 62 are formed between the raw material gas supply pipes 61 . Plasma and radicals generated in the plasma generation region R1 above the raw material gas supply structure 60 can enter the raw material gas dissociation region R2 on the mounting table 31 side through the opening 62 .

As shown in FIG. 3 , a plurality of raw material gas supply ports 63 are formed on the lower surface of the raw material gas supply pipe 61 of the raw material gas supply structure 60 . These raw material gas supply ports 63 are uniformly arranged in the plane of the raw material gas supply structure 60 . The raw material gas supply pipe 61 is connected to a gas pipe 65 which communicates with a raw material gas supply source 64 provided outside the processing container 30 . In the source gas supply source 64 , for example, silane (SiH ₄ ) gas and hydrogen (H ₂ ) gas, which are silane-based gases, can be respectively enclosed as source gases. The gas pipe 65 is provided with a valve 66 , a mass flow controller 67 . With this configuration, predetermined flow rates of silane gas and hydrogen gas are respectively introduced into the raw material gas supply pipe 61 from the raw material gas supply source 64 through the gas pipe 65 . And these silane gas and hydrogen gas are supplied from each raw material gas supply port 63 to the raw material gas dissociation region R2 below.

On the inner peripheral surface of the processing container 30 covering the outer peripheral surface of the plasma generation region R1, a first plasma excitation gas supply port 70 for supplying a plasma excitation gas serving as a raw material of plasma is formed. The first gas supply ports 70 for plasma excitation are formed at a plurality of positions along the inner peripheral surface of the processing container 30 , for example. The first gas supply port 70 for plasma excitation is connected to a first gas supply pipe 72 for plasma excitation. The external first plasma excitation gas supply source 71 is connected. A valve 73 and a mass flow controller 74 are provided in the first plasma excitation gas supply pipe 72 . With this configuration, a predetermined flow rate of the gas for plasma excitation can be supplied from the side to the plasma generation region R1 in the processing chamber 30 . In the present embodiment, for example, argon (Ar) gas is sealed in the first plasma excitation gas supply source 71 as the plasma excitation gas.

On the upper surface of the source gas supply structure 60 , for example, a substantially flat plate-shaped plasma excitation gas supply structure 80 having the same configuration as the source gas supply structure 60 is stacked. The gas supply structure 80 for plasma excitation is comprised from the 2nd gas supply pipe 81 for plasma excitation arrange|positioned in grid form as shown in FIG. In addition, aluminum oxide can be used for the gas supply structure 80 for plasma excitation, for example. In this case, as described above, since alumina is a ceramic, it has higher heat resistance and higher strength than metal materials such as aluminum. In addition, since the plasma generated in the plasma generation region R1 is not trapped, sufficient ions can be irradiated to the glass substrate. Furthermore, a dense film can be formed by irradiating sufficient ions to the film on the glass substrate. In addition, the plasma excitation gas supply structure 80 is resistant to nitrogen trifluoride gas used in dry cleaning. Furthermore, in order to improve the resistance to nitrogen trifluoride gas, the surface of the alumina of the plasma excitation gas supply structure 80 may be covered with diyttrium trioxide or spinel.

As shown in FIG. 3 , a plurality of second plasma excitation gas supply ports 82 are formed on the upper surface of the second plasma excitation gas supply pipe 81 . The plurality of second gas supply ports 82 for plasma excitation are uniformly arranged in the plane of gas supply structure 80 for plasma excitation. Accordingly, the gas for plasma excitation can be supplied from the lower side to the upper side to the plasma generation region R1. In addition, in this embodiment, the gas for plasma excitation is, for example, argon gas. In addition to the argon gas, nitrogen (N ₂ ) gas as a source gas can also be supplied from the plasma excitation gas supply structure 80 to the plasma generation region R1.

Openings 83 are formed between the grid-shaped second plasma excitation gas supply pipes 81, and the plasma and radicals generated in the plasma generation region R1 can pass through the plasma excitation gas supply structure 80 and the raw material. The gas supply structure 60 enters the raw material gas dissociation region R2 below.

The second plasma excitation gas supply pipe 81 is connected to a gas pipe 85 that communicates with a second plasma excitation gas supply source 84 provided outside the processing chamber 30 . In the second plasma excitation gas supply source 84 , for example, argon gas as a gas for plasma excitation and nitrogen gas as a source gas are respectively sealed. The gas pipe 85 is provided with a valve 86 and a mass flow controller 87 . With this configuration, it is possible to supply predetermined flow rates of nitrogen gas and argon gas from the second plasma excitation gas supply port 82 to the plasma generation region R1 .

In addition, the above-mentioned source gas and gas for plasma excitation constitute the processing gas of the present invention. In addition, the source gas supply structure 60 and the plasma excitation gas supply structure 80 constitute the processing gas supply unit of the present invention.

Exhaust ports 90 for exhausting the atmosphere in the processing container 30 are provided on both sides of the bottom of the processing container 30 sandwiching the mounting table 31 . The exhaust port 90 is connected to an exhaust pipe 92 which communicates with an exhaust device 91 such as a turbomolecular pump. The inside of the processing container 30 can be maintained at a predetermined pressure, for example, 20 Pa to 60 Pa, which will be described later, by the exhaust from the exhaust port 90 .

The above plasma film forming apparatus 16 is provided with a control unit 100 . The control unit 100 is, for example, a computer, and has a program storage unit (not shown). A program for controlling the film formation process of the silicon nitride film 23 on the glass substrate G in the plasma film formation apparatus 16 is stored in the program storage unit. Also stored in the program storage section are programs for executing the film formation process in the plasma film formation apparatus 16 by controlling the supply of the above-mentioned source gas, the supply of the gas for plasma excitation, the radiation of microwaves, the operation of the drive system, and the like. program. In addition, the above-mentioned program is a program stored in a computer-readable storage medium such as a computer-readable hard disk (HD), floppy disk (FD), compact disk (CD), magneto-optical disk (MO), and memory card, and may be is a program installed in the control unit 100 from the storage medium.

Next, a method of forming the silicon nitride film 23 performed in the plasma film forming apparatus 16 configured as described above will be described.

First, for example, when the plasma film forming apparatus 16 is activated, the supply flow rate of the argon gas supplied from the first plasma excitation gas supply port 70 and the supply flow rate of the argon gas supplied from the second plasma excitation gas supply port 82 are The concentration of argon gas supplied to the plasma generation region R1 is adjusted to be uniform. In this supply flow rate adjustment, for example, the exhaust device 91 is operated to form the same gas flow in the processing chamber 30 as in the actual film formation process, and the gas supply is set to be supplied from the respective plasma excitation gas supply ports 70 and 82 . Appropriate supply flow of argon. Then, with this supply flow rate setting, film formation was performed on a substrate for actual testing, and it was checked whether or not the film formation proceeded uniformly within the surface of the substrate. When the concentration of the argon gas in the plasma generation region R1 is uniform, the film formation in the substrate surface is uniformly performed. Therefore, when the result of the inspection is that the film formation is not uniformly performed in the substrate surface, change each argon gas concentration. The supply flow rate was set, and film formation was performed on the test substrate again. The above steps are repeated, and the supply flow rates from the plasma excitation gas supply ports 70 and 82 are set so that the film formation is uniform within the substrate surface and the concentration of argon gas in the plasma generation region R1 becomes uniform.

As described above, after the supply flow rates of the plasma excitation gas supply ports 70 and 82 are set, the film formation process on the glass substrate G in the plasma film formation apparatus 16 is started. First, the glass substrate G is carried into the processing container 30 , and is sucked and held on the mounting table 31 . At this time, the temperature of the glass substrate G is maintained at 100°C or lower, for example, 50°C to 100°C. Next, the exhaust in the processing container 30 is started by the exhaust device 91, and the pressure in the processing container 30 is reduced to a predetermined pressure, for example, 20Pa to 60Pa, and this state is maintained. In addition, the temperature of the glass substrate G is not limited to 100° C. or lower, as long as it is a temperature at which the organic EL device A is not damaged, and is determined by the material of the organic EL device A and the like.

Here, as a result of intensive studies by the inventors, it has been found that when the pressure in the processing container 30 is lower than 20 Pa, the silicon nitride film 23 may not be properly formed on the glass substrate G. In addition, it can be seen that when the pressure in the processing container 30 exceeds 60 Pa, the reaction between gas molecules in the gas phase increases, and particles may be generated. Therefore, as described above, the pressure in the processing container 30 is maintained at 20 Pa to 60 Pa.

When the pressure in the processing chamber 30 is reduced, argon gas is supplied from the first gas supply port 70 for plasma excitation on the side, and nitrogen gas is supplied from the second gas supply port 82 for plasma excitation below in the plasma generation region R1. and argon. At this time, the concentration of argon gas in the plasma generation region R1 is kept uniform in the plasma generation region R1. In addition, nitrogen gas is supplied at a flow rate of, for example, 21 sccm. Microwaves having a power of 2.5 kW to 3.0 kW are radiated from radial line slot antenna 42 to plasma generation region R1 directly below at a frequency of, for example, 2.45 GHz. By the irradiation of the microwave, the argon gas is plasmaized in the plasma generation region R1, and the nitrogen gas is radicalized (or ionized). Also, at this time, microwaves traveling below are absorbed by the generated plasma. As a result, high-density plasma is generated in the plasma generation region R1.

Plasma and radicals generated in the plasma generation region R1 pass through the plasma excitation gas supply structure 80 and the source gas supply structure 60 into the lower source gas dissociation region R2. Silane gas and hydrogen gas are supplied to the source gas dissociation region R2 from each source gas supply port 63 of the source gas supply structure 60 . At this time, silane gas is supplied at a flow rate of, for example, 18 sccm, and hydrogen gas is supplied at a flow rate of, for example, 64 sccm. In addition, the supply flow rate of this hydrogen gas is set according to the film characteristic of the silicon nitride film 23 as mentioned later. Silane gas and hydrogen gas are respectively dissociated by the plasma entering from above. Then, the silicon nitride film 23 is deposited on the glass substrate G by using these radicals and the radicals of the nitrogen gas supplied from the plasma generation region R1.

Then, the silicon nitride film 23 is formed, and when the silicon nitride film 23 of a predetermined thickness is formed on the glass substrate G, irradiation of microwaves and supply of processing gas are stopped. Then, the glass substrate G is unloaded from the processing container 30, and a series of plasma film-forming processes are completed.

Here, as a result of intensive studies by the inventors, it has been found that when the silicon nitride film 23 is formed on the glass substrate G by the above-mentioned plasma film formation process, when a processing gas containing silane gas, nitrogen gas, and hydrogen gas is used, Therefore, the controllability of the film characteristics of the silicon nitride film 23 is improved.

6 shows how the wet etching rate of the silicon nitride film 23 with hydrofluoric acid changes when the supply flow rate of hydrogen gas in the process gas is changed using the plasma film forming method of the above-mentioned embodiment. In addition, at this time, the supply flow rate of the silane gas was 18 sccm, and the supply flow rate of the nitrogen gas was 21 sccm. In addition, in the plasma film-forming process, the temperature of the glass substrate G was 100 degreeC.

Referring to FIG. 6, it can be seen that the wet etching rate of the silicon nitride film 23 is reduced by further adding hydrogen gas to the process gas containing silane gas and nitrogen gas. Therefore, the density of the silicon nitride film 23 is improved by the hydrogen gas in the process gas, and the film quality (chemical resistance, density) of the silicon nitride film 23 is improved. In addition, the step coverage of the silicon nitride film 23 is also improved. Furthermore, it can be seen that the refractive index of the silicon nitride film 23 is increased to, for example, 2.0±0.1. Therefore, by controlling the supply flow rate of the hydrogen gas, the wet etching rate of the silicon nitride film 23 can be controlled, and the film characteristics of the silicon nitride film 23 can be controlled.

FIG. 7 shows how the film stress of the silicon nitride film 23 changes when the supply flow rate of the hydrogen gas in the processing gas is changed using the plasma film forming method of the above-mentioned embodiment. In addition, at this time, the supply flow rate of the silane gas was 18 sccm, and the supply flow rate of the nitrogen gas was 21 sccm. In addition, in the plasma film-forming process, the temperature of the glass substrate G was 100 degreeC.

Referring to FIG. 7 , it can be seen that the film stress of the silicon nitride film 23 changes to the negative side (compression side) by further adding hydrogen gas to the process gas containing silane gas and nitrogen gas. Therefore, by controlling the supply flow rate of the hydrogen gas, the film stress of the silicon nitride film 23 can be controlled.

As described above, according to the present embodiment, the film properties of the silicon nitride film 23 can be changed by changing the flow rate of the hydrogen gas in the processing gas. Therefore, since the silicon nitride film 23 can be suitably formed as a sealing film in the organic EL device A, the organic EL device A can be suitably manufactured. In addition, when used for a sealing film, it is preferable that the absolute value of the magnitude of the stress of the sealing film be small.

In addition, in the plasma film forming method of the present embodiment, plasma is generated using microwaves radiated from the radial line slot antenna 42 . Here, as a result of research and discussion by the inventors, it has been found that when the processing gas includes silane gas, nitrogen gas, and hydrogen gas, for example, as shown in FIG. Therefore, according to the present embodiment, even by controlling the power of the microwave, the film stress of the silicon nitride film 23 can be controlled. By optimizing the flow rate of hydrogen gas and optimizing the microwave power, it is possible to obtain a film precisely having desired film properties. Specifically, after determining the power of the microwave, it is only necessary to optimize the flow rate of the hydrogen gas.

However, conventionally, when forming a silicon nitride film on a glass substrate, it is also possible to use the above-mentioned processing gas containing silane gas and ammonia gas (NH ₃ ) gas. However, in a low-temperature environment where the temperature of the glass substrate is 100° C. or lower, the ammonia gas supplied before forming the silicon nitride film corrodes metal electrodes, such as aluminum electrodes, formed on the base of the silicon nitride film. In addition, since the film is formed in a low-temperature environment, unreacted ammonia is trapped in the silicon nitride film. When ammonia is trapped in the silicon nitride film, the ammonia may be degassed from the silicon nitride film after an environmental test or the like, which may deteriorate the organic EL device.

In contrast, in this embodiment, nitrogen gas is used instead of ammonia gas. Therefore, corrosion of the metal electrode of the above-mentioned base and deterioration of the organic EL device can be prevented.

Furthermore, when nitrogen gas is used instead of ammonia gas as in the present embodiment, and hydrogen gas is added to the process gas, the film characteristics of the formed silicon nitride film can be improved as shown in FIG. 9 . That is, the film quality (density) of the silicon nitride film in the stepped portion can be improved. In addition, the upper stage of FIG. 9 shows the appearance of the silicon nitride film in the case of using a processing gas containing silane gas and ammonia gas, and the lower layer shows the state of the silicon nitride film in the case of using a processing gas containing silane gas, nitrogen gas, and hydrogen gas. The appearance of the film. In addition, the left column of FIG. 9 shows the state of the silicon nitride film after film formation, and the right column shows the state of the silicon nitride film after wet etching with buffered hydrofluoric acid (BHF) for 120 seconds.

In the plasma film forming apparatus 16 of the above embodiment, the silane gas and the hydrogen gas are supplied from the raw material gas supply structure 60, and the nitrogen gas and the argon gas are supplied from the plasma excitation gas supply structure 80, but the hydrogen gas may also be supplied from the plasma The excitation gas supply structure 80 supplies it. Alternatively, the hydrogen gas may be supplied from both the source gas supply structure 60 and the plasma excitation gas supply structure 80 . In any case, as described above, by controlling the supply flow rate of hydrogen gas, the film characteristics of the silicon nitride film 23 can be controlled.

Here, as a result of research and discussion by the inventors, it is known that the film quality of the silicon nitride film 23, especially in the case of a dense film quality with the highest (large) Si-N bonding density in the film, the silicon nitride film 23 The refractive index is about 2.0. In addition, from the viewpoint of the barrier property (sealing property) of the silicon nitride film 23, it can be seen that the refractive index is preferably 2.0±0.1.

Therefore, in order to make the above-mentioned refractive index 2.0±0.1, it is preferable to set the ratio of the supply flow rate of nitrogen gas to the supply flow rate of silane gas in the plasma film forming apparatus 16 to be 1 to 1.5. On the other hand, in a typical (conventional) plasma CVD apparatus, when a silicon nitride film is formed using silane gas and nitrogen gas, the ratio of the supply flow rate of nitrogen gas to the supply flow rate of silane gas is usually 10 to 50. In a general plasma CVD apparatus, since a large amount of nitrogen is required as described above, the flow rate of the silane gas is increased to increase the film formation rate, and the flow rate of the nitrogen gas in balance with the increase is required, and a limitation occurs in the exhaust system. Therefore, it becomes difficult to maintain the above-mentioned refractive index of 2.0±0.1 as the refractive index of the silicon nitride film under the condition that the film forming rate is high. Therefore, the plasma film forming apparatus 16 of the present embodiment exhibits an extremely superior effect compared with a normal plasma CVD apparatus.

In addition, by controlling the ratio of the supply flow rate of nitrogen gas to the supply flow rate of silane gas, the film stress of the silicon nitride film 23 can be controlled within the range of the refractive index of 2.0±0.1. Specifically, this film stress can be brought close to zero. Furthermore, this film stress can also be controlled by adjusting the power of the microwave from the radial line slot antenna 42 and the supply flow rate of the hydrogen gas.

In addition, as described above, the nitrogen gas supply flow rate in the plasma film forming apparatus 16 can be made smaller than that of a normal plasma CVD apparatus because it is easy to activate the supplied nitrogen gas and the degree of dissociation can be increased. That is, when the nitrogen gas is supplied from the gas supply structure 80 for plasma excitation, it is positioned very close to the dielectric window 41 where the plasma is generated, so that the second plasma excitation gas of the gas supply structure 80 for plasma excitation can The nitrogen gas discharged from the supply port 82 into the plasma generation region R1 in the processing chamber 30 at a relatively high pressure is more likely to be ionized to generate a large amount of active nitrogen radicals and the like. Furthermore, as described above, in order to increase the degree of dissociation of nitrogen gas, the plasma excitation gas supply structure 80 is arranged within 30 mm from the radial line slot antenna 42 (strictly speaking, the dielectric window 41 ). When the inventors investigated, when the gas supply structure 80 for plasma excitation is arranged in such a position, the gas supply structure 80 for plasma excitation itself is arranged in the plasma generation region R1. Therefore, the degree of dissociation of nitrogen gas can be increased.

In the plasma film forming apparatus 16 of the above-mentioned embodiment, supply of a source gas may be performed simultaneously with plasma generation, or may be performed before plasma generation. That is, first, silane gas and hydrogen gas (or only silane gas) are supplied from the source gas supply structure 60 . Simultaneously with or after the supply of the silane gas and hydrogen gas, argon gas and nitrogen gas (and hydrogen gas) are supplied from the plasma excitation gas supply structure 80 , and microwaves are radiated from the radial line slot antenna 42 . Furthermore, plasma is generated in the plasma generation region R1.

Here, the negative electrode layer 22 containing a metal element is formed on the glass substrate G on which the silicon nitride film 23 is formed. For example, when the organic EL device A including the negative electrode layer 22 is exposed to plasma, the negative electrode layer 22 is peeled off from the light emitting layer 21 and the organic EL element A may be damaged. On the other hand, in this embodiment, since plasma is generated simultaneously with or after the supply of the silane gas and the hydrogen gas, the formation of the silicon nitride film 23 starts simultaneously with the generation of the plasma. Therefore, the surface of the negative electrode layer 22 is protected, the organic EL device A is not exposed to plasma, and the organic EL device A can be manufactured appropriately.

In the above embodiments, the source gas supply port 63 is formed downward from the source gas supply structure 60 , and the second plasma excitation gas supply port 82 is formed upward from the plasma excitation gas supply structure 80 . These raw material gas supply ports 63 and the second plasma excitation gas supply ports 82 may be formed in inclined directions other than the horizontal direction or vertically downward, and are more preferably formed in a direction inclined at 45 degrees from the horizontal direction.

In this case, as shown in FIG. 10 , a plurality of raw material gas supply pipes 61 extending parallel to each other are formed in the raw material gas supply structure 60 . The raw material gas supply pipes 61 are arranged at regular intervals in the raw material gas supply structure 60 . On both sides of the side surface of the raw material gas supply pipe 61 , as shown in FIG. 11 , raw gas supply ports 63 for supplying the raw material gas in the horizontal direction are formed. The raw material gas supply ports 63 are arranged at regular intervals on the raw material gas supply pipe 61 as shown in FIG. 10 . In addition, adjacent raw material gas supply ports 63 are formed to face directions opposite to the mutual horizontal direction. In addition, the plasma excitation gas supply structure 80 may have the same configuration as the above-mentioned source gas supply structure 60 . In addition, the source gas supply structure is arranged such that the source gas supply pipe 61 of the source gas supply structure 60 and the second plasma excitation gas supply pipe 81 of the plasma excitation gas supply structure 80 are substantially in a lattice shape. 60 and a gas supply structure 80 for plasma excitation.

The raw material gas supplied from the raw material gas supply port 63 is mainly deposited in the raw material gas supply port 63 as silicon nitride, and therefore the deposited silicon nitride is removed by dry cleaning during maintenance. In this case, when the raw material gas supply port 63 is formed facing downward, it is difficult for plasma to enter the raw material gas supply port 63 , so the silicon nitride accumulated in the raw material gas supply port 63 may not be completely removed to the inside. remove. In this regard, when the source gas supply port 63 is oriented horizontally as in the present embodiment, plasma generated during dry cleaning enters the source gas supply port 63 . Therefore, silicon nitride can be completely removed to the inside of the source gas supply port 63 . Therefore, after maintenance, the source gas can be appropriately supplied from the source gas supply port 63, and the silicon nitride film 23 can be formed more appropriately.

In addition, the raw material gas supply structure is arranged so that the raw material gas supply pipe 61 of the raw material gas supply structure 60 and the second plasma excitation gas supply pipe 81 of the plasma excitation gas supply structure 80 form a substantially lattice shape. 60 and a gas supply structure 80 for plasma excitation. Therefore, the source gas supply structure 60 and the plasma excitation gas supply structure 80 can be fabricated more easily than each of the source gas supply structure 60 and the plasma excitation gas supply structure 80 itself in a substantially lattice shape. In addition, the plasma generated in the plasma generation region R1 can also easily pass through.

In addition, as shown in FIG. 12 , the raw material gas supply port 63 may be formed such that its inner diameter expands in a tapered shape from the inner side toward the outer side. In this case, plasma enters the inside of the source gas supply port 63 more easily during dry cleaning. Therefore, the silicon nitride accumulated in the source gas supply port 63 can be more reliably removed. In addition, the second plasma excitation gas supply port 82 may also be formed so that its inner diameter expands in a tapered shape from the inner side toward the outer side.

In the above embodiment, the case where the silane gas is used as the silane-based gas has been described, but the silane-based gas is not limited to the silane gas. After research and discussion by the inventors, it has been found that, for example, when disilane (Si ₂ H ₆ ) gas is used, the step coverage of the silicon nitride film 23 is further improved compared to the case where silane gas is used.

In addition, in the plasma film forming apparatus 16 of the above embodiment, plasma is generated by microwaves from the radial line slot antenna 42 , but the generation of this plasma is not limited to this embodiment. As the plasma, for example, CCP (capacitively coupled plasma), ICP (inductively coupled plasma), ECRP (electron cyclotron resonance plasma), HWP (helicon wave plasma, helicon wave excited plasma) or the like can also be used. In either case, since the silicon nitride film 23 is formed in a low-temperature environment where the temperature of the glass substrate G is 100° C. or lower, it is preferable to use high-density plasma.

Furthermore, in the above embodiments, the case where the organic EL device A is manufactured by forming the silicon nitride film 23 as the sealing film on the glass substrate G has been described, but the present invention can also be applied to the case of manufacturing other organic electronic devices. . For example, when an organic transistor, an organic solar cell, an organic FET (Field Effect Transistor, field effect transistor) etc. are manufactured as an organic electronic device, the method for forming a silicon nitride film of the present invention can also be used. Furthermore, in addition to the production of such organic electronic devices, the present invention can also be widely used in the case of forming a silicon nitride film on a substrate in a low-temperature environment where the temperature of the substrate is 100° C. or lower.

As mentioned above, although the suitable embodiment of this invention was described referring drawings, this invention is not limited to this example. Those skilled in the art can naturally conceive of various modifications and amendments within the scope of the ideas described in the claims, and those of course also belong to the technical scope of the present invention.

Symbol Description

1 Substrate processing system

16 Plasma film forming device

20 positive layer

21 luminous layer

22 Negative electrode layer

23 Silicon nitride film

30 disposal containers

31 Carrying table

42 Radial Line Slot Antenna

60 raw gas supply structure

62 opening

63 Raw material gas supply port

70 1st gas supply port for plasma excitation

80 Plasma excitation gas supply structure

82 Second gas supply port for plasma excitation

83 opening

90 Exhaust port

100 Control Department

A organic EL device

G glass substrate

R1 Plasma generation area

R2 Raw material gas dissociation area

Claims (27)

1. the film build method of a silicon nitride film, be to form the film build method of silicon nitride film on the substrate in being accommodated in container handling, and the film build method of this silicon nitride film is characterised in that:

To supplying with the processing gas that comprises silane based gas, nitrogen and hydrogen in described container handling,

Described processing gas excited and generate plasma, implementing to utilize the plasma treatment that this plasma carries out and form silicon nitride film on substrate.

2. the film build method of silicon nitride film as claimed in claim 1 is characterized in that:

Described silicon nitride film uses as the diaphragm seal of organic electronic device.

3. the film build method of silicon nitride film as claimed in claim 1 is characterized in that:

Utilize in the plasma treatment that described plasma carries out, the pressure in described container handling is maintained 20Pa～60Pa.

4. the film build method of silicon nitride film as claimed in claim 1 is characterized in that:

Control the supply flow rate of described hydrogen, thereby control the membrane stress of described silicon nitride film.

5. the film build method of silicon nitride film as claimed in claim 1 is characterized in that:

Described plasma utilizes the described processing gas of microwave-excitation and generates.

6. the film build method of silicon nitride film as claimed in claim 5 is characterized in that:

Control the power of described microwave, thereby control the membrane stress of described silicon nitride film.

7. the film build method of silicon nitride film as claimed in claim 1 is characterized in that:

Described processing gas comprises:

Be used to form the unstrpped gas of described silicon nitride film; With

Be used for generating the plasma exciatiaon gas of described plasma,

Supply with described unstrpped gas when utilizing described plasma exciatiaon to generate described plasma with gas or before generating described plasma.

8. the film build method of silicon nitride film as claimed in claim 1 is characterized in that:

In the described processing gas of supplying with in to described container handling, the supply flow rate of described nitrogen is 1～1.5 with the ratio of the supply flow rate of described silane based gas.

9. the manufacture method of an organic electronic device is characterized in that:

Form organic element on substrate,

Then, to supplying with the processing gas that comprises silane based gas, nitrogen and hydrogen in the container handling of taking in this substrate, described processing gas is excited and generate plasma, the plasma treatment that enforcement utilizes this plasma to carry out, form silicon nitride film as diaphragm seal so that cover the mode of described organic element.

10. the manufacture method of organic electronic device as claimed in claim 9 is characterized in that:

In the plasma treatment of utilizing described plasma to carry out, the pressure in described container handling is maintained 20Pa～60Pa.

11. the manufacture method of organic electronic device as claimed in claim 9 is characterized in that:

Control the supply flow rate of described hydrogen, thereby control the membrane stress of described silicon nitride film.

12. the manufacture method of organic electronic device as claimed in claim 9 is characterized in that:

Described plasma utilizes the described processing gas of microwave-excitation and generates.

13. the manufacture method of organic electronic device as claimed in claim 12 is characterized in that:

Control the power of described microwave, thereby control the membrane stress of described silicon nitride film.

14. the manufacture method of organic electronic device as claimed in claim 9 is characterized in that:

Described processing gas comprises:

Be used to form the unstrpped gas of described silicon nitride film; With

Be used for generating the plasma exciatiaon gas of described plasma,

When utilizing described plasma exciatiaon to generate described plasma with gas or before generating described plasma, supply with described unstrpped gas.

15. the manufacture method of organic electronic device as claimed in claim 9 is characterized in that:

In the described processing gas of supplying with in to described container handling, the supply flow rate of described nitrogen is 1～1.5 with the ratio of the supply flow rate of described silane based gas.

16. a film formation device that forms the silicon nitride film of silicon nitride film on substrate, is characterized in that, comprising:

Take in substrate and to its container handling of processing;

To supplying with the processing gas supply part of the processing gas that comprises silane based gas, nitrogen and hydrogen in described container handling;

Described processing gas is excited and generate the plasma exciatiaon section of plasma; With

Control part, it controls described processing gas supply part and described plasma exciatiaon section,, to implement the plasma treatment of utilizing described plasma to carry out, forms silicon nitride film on substrate.

17. the film formation device of silicon nitride film as claimed in claim 16 is characterized in that:

Described silicon nitride film uses as the diaphragm seal of organic electronic device.

18. the film formation device of silicon nitride film as claimed in claim 16 is characterized in that:

Described control part, control described processing gas supply part, makes in the plasma treatment of utilizing described plasma to carry out, and the pressure in described container handling is maintained 20Pa～60Pa.

19. the film formation device of silicon nitride film as claimed in claim 16 is characterized in that:

Described control part is controlled the supply flow rate of described hydrogen, thereby controls the membrane stress of described silicon nitride film.

20. the film formation device of silicon nitride film as claimed in claim 16 is characterized in that:

The described processing gas of described plasma exciatiaon section's supply microwave-excitation.

21. the film formation device of silicon nitride film as claimed in claim 20 is characterized in that:

Described control part is controlled the power of described microwave, thereby controls the membrane stress of described silicon nitride film.

22. the film formation device of silicon nitride film as claimed in claim 16 is characterized in that:

Described processing gas comprises:

Be used to form the unstrpped gas of described silicon nitride film; With

Be used for generating the plasma exciatiaon gas of described plasma,

Described control part is controlled described processing gas supply part and described plasma exciatiaon section, makes when utilizing described plasma exciatiaon to generate described plasma with gas or before generating described plasma and supplies with described unstrpped gas.

23. the film formation device of silicon nitride film as claimed in claim 16 is characterized in that:

Described control part is controlled described processing gas supply part, and the supply flow rate that makes described nitrogen is 1～1.5 for the ratio of the supply flow rate of described silane based gas.

24. the film formation device of silicon nitride film as claimed in claim 16 is characterized in that:

Described processing gas comprises:

Be used to form the unstrpped gas of described silicon nitride film; With

Be used for generating the plasma exciatiaon gas of described plasma,

Be provided with described plasma exciatiaon section on the top of described container handling,

Be provided with the mounting portion of mounting substrate in the bottom of described container handling,

Between described plasma exciatiaon section and described mounting portion, be provided with plasma exciatiaon structure for gas supply body and the unstrpped gas supplying structure body dividing in described container handling and form described processing gas supply part,

Be formed with in the structure for gas supply body at described plasma exciatiaon: the plasma exciatiaon gas supply port of described plasma exciatiaon with gas supplied with in the zone to described plasma exciatiaon section side; With the peristome that makes the described plasma that generates in the zone of described plasma exciatiaon section side by the zone of described mounting portion side,

Be formed with in described unstrpped gas supplying structure body: the unstrpped gas supply port of the zone of described mounting portion side being supplied with described unstrpped gas; With the peristome that makes the described plasma that generates in the zone of described plasma exciatiaon section side by the zone of described mounting portion side.

25. the film formation device of silicon nitride film as claimed in claim 24 is characterized in that:

Described plasma exciatiaon is disposed at apart from the described plasma exciatiaon 30mm of section with interior position with the structure for gas supply body.

26. the film formation device of silicon nitride film as claimed in claim 24 is characterized in that:

Described unstrpped gas supply port forms towards horizontal direction.

27. the film formation device of silicon nitride film as claimed in claim 26 is characterized in that:

Described unstrpped gas supply port forms its internal diameter and goes toward the outer side tapered shape to enlarge from inboard.

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