TWI426152B - Preparation method of carbonized silicon film - Google Patents

Description

Film forming method of carbonized ruthenium film

The present invention relates to a method of forming a transparent hard film of SiC composition on a substrate using radical assisted sputtering.

In the sputtering of the target, a lanthanoid film is formed on the substrate by a so-called reactive sputtering method in which a reactive gas (O ₂ , N ₂ , CH _{4 ,} etc.) flows together with an inert gas (Ar) ( A method of SiO ₂ , SiC, Si ₃ N ₄ or the like is known (the background art of Patent Document 1). It is also known to form a thin film of a SiC single crystal on a substrate by using a CVD (Chemical Vapor Deposition) apparatus using SiH ₄ as a germanium source gas, wherein the structure of the above CVD apparatus is performed in the same SiC thin film formation process. In the pretreatment stage of the substrate (heating process and high temperature process) and the stage of growing the film to the substrate, or in the cooling stage, the supply of the hydrocarbon gas species is instantaneously switched, and the supply is most suitable for each. Hydrocarbon gas of the type of the stage (Patent Document 2). In addition, a Si _x C _1-x film (where 0 < x < 1) is formed on the substrate by sputtering the target and the carbon target under a mixed atmosphere of inert gas and hydrogen, and is thermally annealed after film formation. A method of producing a semiconductor film is also known (Patent Document 3).

[First technical literature] [Patent Literature]

[Patent Document 1] JP-A-3-271197

[Patent Document 2] JP-A-2010-95431

[Patent Document 3] License No. 3386436

However, in the reactive sputtering method described in the background art 1 of Patent Document 1, since the sputtering efficiency is extremely poor, there is a disadvantage that the film formation takes a long time and the manufacturing cost is high. In the CVD method described in Patent Document 2, SiH ₄ used as a raw material for bismuth is self-igniting, and has a disadvantage that it is extremely dangerous in the process. Further, in the CVD method, it is necessary to carry out a process after setting the substrate temperature to a high temperature such as 1400 ° C, and it is not suitable to treat a substrate having low heat resistance such as a plastic substrate. The semiconductor film obtained by the method described in Patent Document 3 cannot be used for applications requiring transparency because of its low light transmittance.

In one aspect of the present invention, there is provided a film forming method which can efficiently form a light transmittance and a high film strength in a short time and safely, even on a substrate having low heat resistance, and can be used for optical use. Tantalum carbide film.

According to the present invention, there is provided a method for forming a tantalum carbide film, which is a method for forming a tantalum carbide film on a moving substrate while independently controlling the splash of the target and the exposure of the plasma in a vacuum state. The utility model is characterized in that: under an inert gas atmosphere, a plurality of targets having different materials are respectively splashed, and an intermediate film containing bismuth and carbon is formed on the substrate; and the intermediate film is exposed to an atmosphere of a mixed gas of an inert gas and hydrogen. The resulting plasma is converted into an ultra-thin film, and thereafter the formation of the intermediate film and the film conversion of the ultra-thin film are repeated on the ultra-thin film.

The above invention is achieved by the use of a film forming apparatus (exciting auxiliary sputtering apparatus) which spatially separates a reaction process area and a plurality of film forming process areas in a single vacuum container. In order to be able to independently control the composition of the processing in each region.

Specifically, the present invention provides a film forming method of a tantalum carbide film, which is a method of forming a tantalum carbide film on a moving substrate by using the film forming apparatus as an example, and is characterized by an inert gas atmosphere. Separating each of the plurality of targets in each of the film forming process regions, and forming an intermediate film containing tantalum and carbon on the substrate; exposing the intermediate film to the inert gas in the reaction process region The plasma generated in the atmosphere of the mixed gas with hydrogen is converted into an ultrathin film, and thereafter the formation of the intermediate film and the film conversion of the ultrathin film are repeated on the ultrathin film.

According to the above invention, the intermediate film of ruthenium and carbon which is formed by being sputtered under an inert gas and formed on the substrate is exposed to a plasma generated under an atmosphere of a mixed gas of an inert gas and hydrogen, and the film is converted. The film is formed into an ultra-thin film, and thereafter, the above operation is repeated, whereby the tantalum carbide film can be efficiently formed in a short time and safely, even on a substrate having low heat resistance.

The tantalum carbide film formed by the method of the present invention has high light transmittance and film strength and is suitable for use in optical applications. That is, an optical substrate having a film of tantalum carbide on the substrate, a light transmittance of 70% or more at a wavelength of 650 nm to 700 nm, and a Vickers hardness HV of 1300 or more on the film side can be obtained by the method of the present invention.

[Best form for implementing the invention]

Hereinafter, an embodiment of the method of the present invention will be described in detail based on the drawings.

First, a configuration example of a film forming apparatus which can realize the method of the present invention will be described.

As shown in FIGS. 1 and 2, the film forming apparatus 1 of the present embodiment (hereinafter simply referred to as "sputtering apparatus 1") is a device capable of implementing an excitation assisted sputtering (RAS) method, and has a vacuum container 11 It is a hollow body having a substantially rectangular parallelepiped shape. The piping 15a for exhaust is connected to the vacuum vessel 11, and the vacuum pump 15 for exhausting inside the vessel 11 is connected to the piping. The vacuum pump 15 is constituted by, for example, a rotary pump, a turbo molecular pump (TMP), or the like. The substrate holder 13 is disposed in the vacuum container 11. The outer peripheral surface of the substrate holder 13 is constituted by a cylindrical member which can hold the substrate S as a film formation object in the vacuum container 11. The substrate holder 13 of this example is disposed in the vacuum container 11, and the rotation axis Z extending in the cylinder direction is directed in the vertical direction (Y direction) of the vacuum container 11. The substrate holder 13 is rotated about the axis Z by driving the motor 17.

In this example, two sputtering sources and one plasma source 80 are disposed around the substrate holder 13 disposed in the vacuum vessel 11.

Film forming process regions 20, 40 are formed on the front surface of each of the sputtering sources. The four sides of each of the regions 20, 40 are surrounded by the partition walls 12, 14 projecting from the inner wall of the vacuum vessel 11 toward the substrate holder 13, and are partitioned to ensure that the respective regions 20, 40 are inside the vacuum vessel 11. Independent space. Similarly, on the front surface of the plasma source 80, a reaction process region 60 is formed. This region 60 is also surrounded by the partition walls 16 projecting from the inner wall of the vacuum vessel 11 toward the substrate holder 13 in the same manner as the regions 20, 40, thereby ensuring the region 60 in the interior of the vacuum vessel 11 and the region 20, 40 separate spaces. In this example, it is configured to be independently controllable in each of the regions 20, 40, and 60.

Each of the sputtering sources of this example is constituted by a double cathode type having two magnetron sputtering electrodes 21a, 21b (or 41a, 41b). At the time of film formation (described later), the one end side surfaces of the respective electrodes 21a and 21b (or 41a, 41b) are held in contact with or away from the targets 29a and 29b (or 49a, 49b). The other end side of each of the electrodes 21a and 21b (or 41a, 41b) is configured to be connected to an AC power source 23 (or 43) as a power supply via a transformer 24 (or 44) as a power controller for adjusting the amount of electric power. An AC voltage of, for example, about 1 k to 100 kHz is applied to each of the electrodes 21a and 21b (or 41a, 41b).

Each sputtering source is a gas supply for connection sputtering. The gas supply for sputtering of this example is a flow controller including a gas cylinder 26 (or 46) for storing a gas for sputtering, and a flow rate for adjusting a sputtering gas supplied from the gas cylinder 26 (or 46). (mass flow controller) 25 (or 45). The sputtering gas is introduced into the region 20 (or 40) via a pipe. The flow controller 25 (or 45) is means for adjusting the flow rate of the sputtering gas. The sputtering gas from the gas cylinder 26 (or 46) is regulated by the flow controller 25 (or 45) to be introduced into the region 20 (or 40).

The plasma source 80 of this example has a case 81 and a dielectric plate 83 fixed to the case 81, wherein the dielectric plate 83 is fixed to an opening formed in the wall surface of the vacuum container 11 to block the opening. . On the other hand, since the dielectric plate 83 is fixed to the casing 81, the antenna housing 83 is formed in a region surrounded by the casing 81 and the dielectric plate 83. The antenna storage chamber communicates with the vacuum pump 15 via the line 15a, and the inside of the antenna housing chamber can be evacuated by a vacuum generated by the vacuum pump 15 to be in a vacuum state.

The plasma source 80 includes antennas 85a and 85b in addition to the case 81 and the dielectric plate 83. The antennas 85a and 85b are connected to the high-frequency power source 89 via a matching box 87 that houses a matching circuit. The antennas 85a and 85b are supplied with electric power from the high-frequency power source 89, and an induced electric field is generated inside the vacuum vessel 11 (area 60), and plasma is generated in the region 60. In the configuration of this embodiment, an alternating current voltage having a frequency of 1 to 27 MHz is applied to the antennas 85a and 85b from the high-frequency power source 89, and a plasma for the reaction processing gas is generated in the region 60. A variable capacitor is provided in the matching box 87 so that the electric power supplied from the high-frequency power source 89 to the antennas 85a and 85b can be changed.

The plasma source 80 is a gas supply for connection reaction treatment. The gas supply for reaction processing of this example is a flow rate controller 67 including a gas storage tank 68 for storing the reaction processing gas and a flow rate for adjusting the reaction processing gas supplied from the gas cylinder 68. The reaction treatment gas is introduced into the region 60 via a pipe. The flow rate controller 67 is means for adjusting the flow rate of the reaction processing gas. The reaction treatment gas from the gas cylinder 68 is regulated by the flow controller 67 to be introduced into the region 60.

Further, the gas supply for the reaction treatment is not limited to the above configuration (that is, a configuration including a gas cylinder and a flow controller), and may be a configuration including a plurality of gas cylinders and a flow controller (hereinafter described herein) For example, a configuration includes two gas cylinders for storing an inert gas and hydrogen, and two flow controllers for adjusting a flow rate of each gas supplied from each gas cylinder.

Next, an example of the method of the present invention using the sputtering apparatus 1 will be described (please refer to the flowchart of FIG. 3).

(1) First, prepare for film formation. Specifically, the targets 29a, 29b (or 49a, 49b) are first placed on the electrodes 21a, 21b (or 41a, 41b). At the same time, the substrate S as a film formation target is placed on the substrate holder 13 in addition to the vacuum container 11, and is accommodated in a load lock of the vacuum container 11.

As the substrate S, a metal substrate such as stainless steel or the like can be applied in addition to a plastic substrate (organic glass substrate) or an inorganic substrate (inorganic glass substrate), and the thickness thereof is, for example, 0.1 to 5 mm. In addition, examples of the inorganic glass substrate as an example of the substrate S include soda-lime glass (6H to 7H) and borosilicate glass (6H to 7H). Further, the number in the parentheses of the inorganic glass substrate is a value of pencil hardness measured according to the method of JIS-K5600-5-4.

A plurality of substrates S are intermittently arranged on the outer circumferential surface of the substrate holder 13 along the rotation direction (lateral direction) of the substrate holder; and in a direction parallel to the axis Z of the substrate holder 13 (vertical direction, Y direction) A plurality of substrates S are intermittently arranged.

The targets 29a and 29b (or 49a, 49b) are materials in which the film material is formed into a flat plate shape, and the longitudinal direction thereof is parallel to the rotation axis Z of the substrate holder 13, and the surface in the parallel direction and the side of the substrate holder 13 are formed. The opposite direction is maintained on the surface of each of the electrodes 21a, 21b (or 41a, 41b). In this example, a ruthenium (Si) constituting member is used as the targets 29a and 29b, and a carbon (C) constituting member is used as the targets 49a and 49b.

Further, as the target materials 49a and 49b, a carbon nanotube (SiC) composition of a compound having a plurality of elements may be used instead of the carbon (C) composition. Further, in the same manner, a ruthenium (Si) constituting member may be used as the targets 29a and 29b.

As the target of the niobium carbide target, those obtained by, for example, the following methods can be used. First, a slurry of SiC is prepared by adding a dispersant, a binder (for example, an organic binder), and water to a tantalum carbide powder to form a slurry of SiC (for example, casting, press forming, and extrusion molding). Etc.) to obtain a shaped body. Next, the obtained molded body is baked at a temperature of, for example, 1450 to 2300 ° C (preferably 1500 to 2200 ° C, more preferably 1600 to 1800 ° C) in a vacuum or a non-oxidizing atmosphere, and then sintered. Next, the sintered body is impregnated with molten Si in a vacuum or a reduced pressure non-oxidizing atmosphere at a temperature of 1450 to 2200 ° C (preferably 1500 to 2200 ° C, more preferably 1500 to 1800 ° C). The pores of the sintered body are filled with Si. In this example, a SiC target having a density of 3 g/cm ³ or more obtained by the above steps can be used. Such a high-density and uniform SiC target can stably discharge at a high input power at the time of sputtering deposition, and can contribute to an improvement in film formation speed.

Next, after the substrate holder 13 is moved to the film forming chamber of the vacuum container 11, the inside of the vacuum container 11 is sealed in a state where the gate between the load chamber and the load chamber is closed, and the vacuum container 15 is used to make the inside of the vacuum container 11 10 ^-5 to 0.1. High vacuum state of Pa degree. At this time, the valve is opened, and the antenna accommodation chamber of the plasma source 80 is also exhausted.

Next, the drive motor 17 is started to rotate the substrate holder 13 about the axis Z. Then, the substrate S held on the outer circumferential surface of the substrate holder 13 revolves around the rotation axis-axis Z of the substrate holder 13, and moves between the positions facing the regions 20 and 40 and the position facing the region 60. In this example, the rotation speed of the substrate holder 13 may be 10 rpm or more, preferably 50 rpm or more, more preferably 80 rpm or more. In the case of 50 rpm or more, the effect of introducing hydrogen can be appropriately exhibited when exposed to the plasma, and the light transmittance of the tantalum carbide film formed on the substrate S and the film strength can be easily promoted. Further, in this example, the upper limit of the rotational speed of the substrate holder 13 is, for example, about 150 rpm, preferably 100 rpm.

The above is the preparation of the film formation in the step of FIG. 3 (hereinafter simply referred to as "S") 1.

Then, the sputtering treatment in the regions 20 and 40 and the plasma exposure treatment in the region 60 are sequentially repeated, and a film made of tantalum carbide is formed on the surface of the substrate S to form a final film having a predetermined film thickness.

In this example, an intermediate film is formed on the surface of the substrate S by a continuous sputtering process, and the intermediate film is film-converted by the subsequent plasma exposure treatment to become an ultrathin film. Then, two sputtering treatments and plasma exposure treatments are repeatedly performed, and the next ultra-thin film is deposited on the ultra-thin film, and the operation is repeated until the final film is completed.

Further, in the present example, the "intermediate film" means a film formed by the two regions of the region 20 and the region 40. "Ultra-thin film" refers to the term used after the deposition of a plurality of ultra-thin films to form the final film (the film of the target film thickness), in order to prevent confusion with the final "film", which is far more than the final " The film is also used in a thin sense.

(2) Next, in S2 of Fig. 3, film formation is started. The sputtering treatment of this example is carried out as follows.

First, after confirming the stabilization of the pressure in the vacuum vessel 11, the pressure in the region 20 is adjusted to, for example, 0.05 to 0.2 Pa, and then the sputtering gas of a predetermined flow rate is introduced into the region 20 from the gas cylinder 26 via the flow rate controller 25.

In this example, an inert gas is used alone as a gas for sputtering, and it is not used in combination with a reactive gas such as nitrogen or oxygen. The film formation rate is not lowered as compared with the case of the reactive sputtering method in which the reactive gas is introduced at the same time. The introduction flow rate of the inert gas in this example is, for example, about 100 to 600 sccm, preferably about 150 to 500 sccm. Then, the periphery of the targets 29a and 29b is an inert gas atmosphere. In this state, an alternating current voltage is applied from the alternating current power source 23 to each of the electrodes 21a and 21b via the transformer 22, and an alternating electric field is applied to the targets 29a and 29b.

In this example, the power (sputtering power) is supplied so that the sputtering power density at the targets 29a and 29b becomes 1.5 W/cm ² to 2.0 W/cm ² , preferably 1.6 W/cm ² to 1.8 W. /cm ² , particularly preferably about 1.7 W/cm ² . The "power density" refers to the meaning of electric power (W) per unit area supplied to the targets 29a, 29b (or 49a, 49b) (the same applies hereinafter).

By supplying electric power to the targets 29a and 29b, the target 29a becomes a cathode (negative electrode) at a certain point of time, and at this time, the target 29b must be an anode (positive electrode). After the change of the direction of the alternating current at the next time point, the target 29b becomes the cathode (negative electrode), and the target 29a becomes the anode (positive electrode). Thus, by causing the pair of targets 29a and 29b to alternate into an anode and a cathode, a part of the sputtering gas (inert gas) around the respective targets 29a and 29b emits electrons and is ionized. Since the magnets disposed on the respective electrodes 21a and 21b form a leakage magnetic field on the surfaces of the respective targets 29a and 29b, the electrons are drawn in a magnetic field generated near the surface of each of the targets 29a and 29b. Rotate like a curve. Strong plasma is generated along the orbit of the electron, and ions of the sputtering gas in the plasma are accelerated toward the target in the negative potential state (cathode side), and each target is impinged upon impinging on each target 29a, 29b. The atoms, particles, and the like on the surface of the materials 29a and 29b (thorium atoms, ruthenium particles, etc.) are sputtered (splashing). The atoms, particles, and the like are film raw material of a raw material of a film, and adhere to the surface of the substrate S.

The above is the splash of the target (or carbon target) in the region 20 in S21 of Fig. 3.

In addition, when sputtering is performed, there is adhesion of an incomplete reactant having low conductivity or low conductivity on the anode, but after the anode is converted into a cathode by an alternating electric field, these incomplete reactants may be splashed. The surface of the target will become the original clean state. While the pair of targets 29a and 29b alternately become anodes and cathodes, a constant anode potential can be obtained, and a change in the plasma potential (generally substantially equal to the anode potential) can be prevented, so that the film raw material is stably attached to the substrate. The surface of S.

In this example, the region 40 is also actuated while the operation of the region 20 (the supply of the sputtering gas and the supply of electric power from the AC power source 23). Specifically, the pressure in the region 40 is adjusted to, for example, 0.05 to 0.2 Pa, and then the sputtering gas of a predetermined flow rate is introduced into the region 40 from the gas cylinder 46 via the flow controller 45.

In the present embodiment, the inert gas is used alone as the sputtering gas, and the introduction flow rate of the inert gas is, for example, about 100 to 600 sccm, preferably about 150 to 500 sccm. Then, the periphery of the targets 49a and 49b also becomes an inert gas atmosphere. In this state, an alternating current voltage is applied from the alternating current power source 43 to the respective electrodes 41a and 41b via the transformer 42, and an alternating electric field is applied to the targets 49a and 49b.

In this example, it is important that the supplied electric power is such that the sputtering power density of the targets 49a and 49b becomes a predetermined multiple of the power density of the splash targets 29a and 29b (for example, 4.5 to 5.5 times, preferably 4.8 times ~ 5.2 times, especially good about 5 times). The "power density" refers to the meaning of electric power (W) per unit area supplied to the targets 29a, 29b (or 49a, 49b) (the same applies hereinafter). Thereby, there is an advantage that a tantalum carbide film having high light transmittance and high film strength can be efficiently formed. When the power density of the targets 29a and 29b is 1.5 W/cm ² to 2.0 W/cm ² , the power density of the targets 49 a and 49 b is, for example, 8.5 W/cm ² to 9.0 W/cm ² , preferably 8.5 W/cm ² to 8.7 W/cm ² , particularly preferably about 8.6 W/cm ² .

Further, when a bismuth (Si) constituting member is used as the targets 29a and 29b and a ruthenium carbide (SiC) constituting member is used as the targets 49a and 49b, the power supplied can cause the sputtering power density at the targets 49a and 49b. The power density of the splash targets 29a and 29b is a predetermined multiple (for example, 2 to 3 times, preferably 2.3 to 2.8 times, particularly preferably about 2.5 times). At this time, the above-described target 29a, 29b of the power density of ^{3.0W / cm 2 ~ 4.0W / cm} 2 ( preferably 3.3 ~ 3.7W / cm ^2, particularly preferably 3.5W / ² cm & lt left), in The power density of the targets 49a and 49b may be, for example, 7.5 W/cm ² to 10 W/cm ² , preferably 8.2 W/cm ² to 9.3 W/cm ² , particularly preferably about 8.8 W/cm ² .

On the other hand, when a ruthenium carbide (SiC) constituting member is used as the targets 29a and 29b and a carbon (C) constituting member is used as the targets 49a and 49b, the supplied electric power can cause sputtering on the targets 29a and 29b. The power density is a predetermined multiple of the power density of the splash targets 49a and 49b (for example, 0.5 to 1.2 times, preferably 0.7 to 1.0 times, particularly preferably about 0.8 times). In this case, when the power density of the targets 49a and 49b is 10 W/cm ² to 18 W/cm ² (preferably 13 to 15 W/cm ² , particularly preferably about 14 W/cm ² ), the target material 29a, 29b, for example, power density may be 7 ~ 15W / cm ^2, preferably 9 ~ 13W / cm ^2, particularly preferably from about 11W / cm ^2.

By supplying electric power to the targets 49a and 49b, the target 49a becomes a cathode (negative electrode) at a certain point in time as described above, and at this time, the target 49b is always an anode (positive electrode). After the change of the direction of the alternating current at the next time point, the target 49b becomes the cathode (negative electrode), and the target 49a becomes the anode (positive electrode). Thus, by causing the pair of targets 49a and 49b to alternate into an anode and a cathode, a part of the sputtering gas (inert gas) around the respective targets 49a and 49b emits electrons and is ionized. Since the magnets disposed on the respective electrodes 41a and 41b form a leakage magnetic field on the surfaces of the respective targets 49a and 49b, the electrons are rotated in a magnetic field generated in the vicinity of the surface of each of the targets 49a and 49b. Strong plasma is generated along the orbit of the electron, and ions of the sputtering gas in the plasma are accelerated toward the target in the negative potential state (cathode side), and each target is hit by impinging on each of the targets 49a and 49b. The atoms, particles, and the like (carbon atoms, carbon particles, etc.) on the surface of the materials 49a and 49b are sputtered (splashing). The atoms, particles, and the like are thin film raw material of a raw material of a film, and adhere to a ruthenium atom, ruthenium particles, or the like adhering to the substrate S to form an intermediate film.

The above is the splash of the carbon target (or the niobium carbide target) in the region 40 in S22 of Fig. 3 .

The intermediate film of this example is composed of a mixture of elements (germanium atoms or cerium particles, and carbon atoms or carbon particles), and it is presumed that it is not in a strong chemical bonding state.

The plasma treatment was carried out as follows. In this example, the actuation of zone 20 begins with the actuation of zone 20, 40. Specifically, the reaction processing gas of a predetermined flow rate is introduced into the region 60 from the gas cylinder 68 via the flow rate controller 67, and the periphery of the antennas 85a and 85b is set to a predetermined gas atmosphere.

The pressure in the region 60 is maintained at, for example, 0.07 to 1 Pa. Further, when at least the region 60 is generating plasma, the internal pressure of the antenna accommodation chamber is maintained at 0.001 Pa or less. In a state where the reaction processing gas is introduced from the gas cylinder 68, a voltage of 100 k to 50 MHz (preferably 1 M to 27 MHz) is applied to the antennas 85a and 85b from the high-frequency power source 89, and the antenna in the facing region 60 is applied. The areas of 85a, 85b produce plasma. In the case where the substrate is made of a glass material, the electric power (the plasma processing power) supplied from the high-frequency power source 89 can be, for example, 3 kW or more, preferably 4 kW or more, more preferably 4.5 kW or more. In the case of constituting the substrate S, for example, it is possible to have a small electric power of 1 kW or less, preferably 0.8 kW or less, more preferably 0.5 kW or less.

In this example, it is important to use a mixed gas of an inert gas and hydrogen as a reaction treatment gas. As a result, in the plasma produced in this example, ions (H ₂ ⁺ ) of hydrogen molecules (H ₂ ) and/or active species of hydrogen may be present, which are guided to the region 60. After the substrate holder 13 is rotated and the substrate S is introduced into the region 60, the intermediate film composed of a mixture of tantalum and carbon formed on the surface of the substrate S in the regions 20, 40 is subjected to plasma exposure treatment, and the film is converted into a chemical Sexually strong bonding states with carbon compounds to form ultra-thin films.

The above is the plasma exposure of the intermediate film in the region 60 in S23 of Fig. 3.

In this example, the steps S21 to S23 of FIG. 3 (that is, the two-way sputtering treatment and the plasma exposure treatment) are repeated until the ultra-thin film formed on the surface of the substrate S has a predetermined film thickness (for example, 3 μm). The above is preferably about 3 to 7 μm) (in the case where S3 is No. The film deposition step). Thereby, a final film (SiC film) having a desired film thickness is formed on the substrate S.

The inventors of the present invention have experimentally ascertained the fact that a plasma generated under an atmosphere of a mixed gas of an inert gas and hydrogen is brought into contact with the intermediate film to convert the film into an ultrathin film, and thereafter the ultrathin film is accumulated to a predetermined film thickness. On the substrate S, a tantalum carbide film having a high light transmittance and a high film strength can be formed. The reason why the above-described treatment is carried out to obtain a carbide film excellent in film quality is not fully understood. In this example, the deposition of the intermediate film and the exposure under the plasma are each independent in time, and the above steps are periodically repeated, as compared with a general continuous film formation (vacuum vapor deposition method, etc.). It is very different in composition. Also in this case, the deposited intermediate film is exposed to a specific plasma generated under a mixed gas atmosphere of an inert gas containing hydrogen. Imagine, it is presumed that such a specific plasma is in contact with an intermediate film which efficiently absorbs ions (H ₂ ⁺ ) and hydrogen from hydrogen molecules in the plasma when the film is converted into an ultra-thin film. As a result of the energy of the active material or the like, the light transmittance and the film strength of the tantalum carbide film as the final film are improved by achieving high-strength interatomic bonding. The inventors of the present invention have speculated that, in particular, ions (H ₂ ⁺ ) of hydrogen molecules in the plasma have an effect of promoting bonding of atoms in the intermediate film.

In this example, the mixing ratio of the inert gas to the hydrogen is preferably 97:3 to 80:20 in terms of volume (that is, the hydrogen concentration is 3 to 20%), more preferably 97:3 to 90:10 (hydrogen concentration). 3~10%), and more preferably 97:3~94:6 (hydrogen concentration 3~6%), especially good at 95:5 (hydrogen concentration about 5%). As the hydrogen concentration increases, the light transmittance of the obtained tantalum carbide film tends to become high, but if it is excessively too high (for example, more than 20%), it may be hindered in safety management in the process. At the same time, the balance between the light transmittance of the formed tantalum carbide film and the film strength tends to be deteriorated. On the other hand, if the hydrogen concentration is too low, the light transmittance of the obtained hydrocarbon film is lowered.

In this example, the introduction flow rate of the mixed gas is, for example, about 300 to 1000 sccm, preferably about 400 to 600 sccm. When the introduction flow rate of the mixed gas is small, the light transmittance of the formed tantalum carbide film tends to decrease together with the film strength. Conversely, if there is too much traffic to be imported, there is a security problem.

Further, in the above-described sputtering treatment and plasma exposure treatment, it is generally considered to use, for example, argon, helium or the like as an inert gas. In this example, the case of using argon as an inert gas is exemplified.

(3) In the case of Yes in S3 of Fig. 3, the above steps are terminated (S4). Specifically, the re-rotation of the substrate holder 13 is stopped, the vacuum state inside the vacuum container 11 is released, the substrate holder 13 is taken out from the vacuum container 11, and the processed substrate S is recovered from the substrate holder 13.

The tantalum carbide thin film formed on the substrate S in this example has high light transmittance and film strength. Specifically, in the state in which the tantalum carbide thin film is provided on the substrate S, the light transmittance at a wavelength of 650 nm to 700 nm is 70% or more, preferably 75% or more, and the Vickers hardness HV on the film side is 1300 or more. It is 1500 or more, preferably 1700 or more, more preferably 1800 or more. Further, the dynamic friction coefficient μk may be 0.5 or less. Thus, an optical substrate on which a tantalum carbide film is formed on the substrate S can be used for, for example, a window material of a sand blast apparatus.

The Vickers hardness HV is a type of indentation hardness and is a type generally used to indicate the hardness of an object. The measurement method is to use a positive quadrangular pyramid of a diamond having an angle of 136° with respect to the surface as a pressure head, and to obtain a diagonal length of a quadrangular indentation generated when the indenter is pressed into the test piece with a constant load. From this, the surface area of the indentation was obtained from the length of the diagonal line, and the value obtained by dividing the load by the surface area was obtained as the Vickers hardness. This Vickers hardness is not attached to the unit and is only expressed as a numerical value.

(4) The embodiments described above are described in order to facilitate understanding of the above invention, and are not described in order to limit the invention. Therefore, the respective elements disclosed in the above embodiments are intended to include all design changes, equivalents, and the like belonging to the technical scope of the invention described above.

In the above embodiment, a final film (barium carbide film) having a desired film thickness may be formed on the substrate, and then post-plasma treatment may be applied. Specifically, first, when the rotation of the substrate holder 13 is stopped, the operations in the regions 20 and 40 (the supply of the sputtering gas and the supply of the electric power from the AC power sources 23 and 43) are stopped. On the other hand, the actuation of zone 60 continues as it is. That is, in the region 60, the supply of the reaction processing gas and the supply of electric power from the high-frequency power source 89 are continued, and plasma is continuously generated. In this state, after the substrate holder 13 is rotated again and the substrate S is transported to the region 60, the tantalum carbide film formed on the substrate S is subjected to plasma treatment (post-treatment) in the process of passing through the region 60. By applying a post-plasma treatment, the final film is expected to have an improved light transmittance.

In the case where the plasma treatment is applied in this example, the plasma exposure treatment for forming the tantalum carbide film and the post-plasma treatment after the formation of the tantalum carbide film may be carried out under the same conditions, or may be carried out under different conditions.

In the case of applying post-plasma treatment, for example, the concentration of hydrogen in the mixed gas may also be varied. For example, the mixing ratio of the inert gas to the hydrogen is 95:5 in the plasma treatment in forming the tantalum carbide film, and 93:7 in the plasma post-treatment, so that the latter has a higher hydrogen concentration than the former. The opposite can also be done. Further enhancement of the light transmittance can be expected by the latter having a higher hydrogen concentration than the former.

Further, in the case of applying the post-plasma treatment, the plasma processing power (electric power supplied from the high-frequency power source 89) may be changed with respect to the plasma exposure treatment when the tantalum carbide film is formed. In this case, the box 87 can be matched for adjustment. The post-plasma treatment time is, for example, in the range of about 1 to 60 minutes as an appropriate time.

In the above-described embodiment, the case where the tantalum carbide thin film is formed by using the sputtering apparatus 1 is exemplified, and the sputtering apparatus 1 is an excitation-assisted sputtering method which can realize magnetron sputtering which is an example of sputtering. However, it is not limited thereto, and other sputtering methods may be used to form a film. The film forming apparatus used in the above other sputtering method is another known sputtering such as bipolar sputtering which does not use magnetron discharge. However, the atmosphere at the time of sputtering is an inert gas atmosphere in any case.

[Examples]

Next, an embodiment in which the embodiment of the above invention is further embodied will be described, and the invention will be described in more detail.

<Experimental Examples 1 to 5>

By using the sputtering apparatus 1 shown in FIGS. 1 and 2, BK7 of a plurality of glass substrates is provided as the substrate S on the substrate holder 13, and sputtering in the region 20 is repeated over the following conditions in the region 40. The sputtering and the plasma exposure in the region 60 (thin film deposition step) were carried out to obtain a sample of each experimental example in which a silicon carbide film having a thickness of 4 μm was formed on the substrate S.

‧ Film formation rate: 0.1nm/s

‧ substrate temperature: room temperature

<<Sputter in area 20>>

‧ Sputtering gas: Ar

‧Barrier pressure: 0.1Pa

‧Injection flow rate of sputtering gas: 150sccm

‧Targets 29a, 29b: 矽 (Si)

‧ Sputtering power density: 1.7W/cm ²

‧ Frequency of alternating voltage applied to electrodes 21a, 21b: 40 kHz

<<Sputtering in area 40>>

‧ Sputtering gas: Ar

‧Barrier pressure: 0.1Pa

‧Injection flow rate of sputtering gas: 150sccm

‧Targets 49a, 49b: Carbon (C)

‧ Sputtering power density: 8.6W/cm ²

(corresponding to splashing about 5 times the power density of the targets 29a, 29b made of bismuth (Si))

‧ Frequency of alternating voltage applied to electrodes 41a, 41b: 40 kHz

<<Plastic exposure in area 60>>

‧Reaction treatment gas: Ar+H ₂

‧ Hydrogen concentration in the gas for reaction treatment: Please refer to Table 1.

‧The gas pressure of the reaction treatment gas: 0.3Pa

‧Introduction flow rate of reaction treatment gas: 500sccm

‧ Power supplied from the high-frequency power source 89 to the antennas 85a and 85b (plasma processing power): 2 kW

‧ Frequency of AC voltage applied to antennas 85a, 85b: 13.56 MHz

<<Evaluation>>

The obtained samples were evaluated for cropness by the following methods, and the results are shown in Table 1.

(1) Evaluation of film strength

The hardness of the surface of the tantalum carbide film of the experimental sample was measured using a micro hardness tester (MMT-X7, manufactured by MATSUZAWA Co., Ltd.) under the following measurement conditions.

‧Indenter shape: Vickers indenter (a=136°)

‧Measurement environment: temperature 20 ° C ‧ relative humidity 60%

‧ Test load: 25gf

‧Load speed: 10μ/s

‧creep under load time: 15 seconds

(2) Evaluation of light transmittance

The light transmittance at a wavelength of 650 nm to 700 nm was measured using a spectrophotometer (trade name: U-4000, manufactured by Hitachi, Ltd.).

(3) Evaluation of slidability

The automatic friction wear analysis device (Triboster TS501: manufactured by Kyowa Interface Science Co., Ltd.) was used to measure the carbonization of the sample under the conditions of a load of 50 g, a speed of 60 mm/min, and a number of measurements: 10 round trips. The coefficient of dynamic friction (μk) on the side of the film.

The following items can be understood according to Table 1. First, regarding the Vickers hardness HV of the surface of the tantalum carbide film, when the hydrogen concentration in the mixed gas is from 0% to 10%, it is seen that the Vickers hardness tends to increase as the value thereof increases. When the hydrogen concentration exceeds 10%, the higher the value is, the lower the Vickers hardness tends to be. Next, with respect to the light transmittance of the sample of the experimental example, it was found that as the concentration of hydrogen in the mixed gas became higher, the light transmittance increased.

In particular, in Test Examples 2 to 5 (hydrogen concentration: 3 to 20%), when HV was 1300 or more and light transmittance was 70%, it was confirmed that good results were obtained. In the sample of Experimental Example 3, it was confirmed that the light transmittance and the film strength were excellent. On the other hand, in Experimental Example 1 (zero hydrogen concentration), HV was 1200 and the hardness was insufficient, and the light transmittance was 50%, which was insufficient.

In addition, as the dynamic friction coefficient μk on the film side increases as the hydrogen concentration in the mixed gas increases, the value tends to increase, that is, the improvement in slidability can be confirmed.

<Experimental Example 6~10>

The targets 49a and 49b located in the region 40 are changed to be made of tantalum carbide (SiC). Further, the sputtering power density of the targets 29a and 29b made of yttrium (Si) in the region 20 is changed to 3.5 W/cm ² , and the sputtering power density of the targets 49a and 49b located in the region 40 is changed to 8.8 W/cm ² (corresponding to about 2.5 times the power density of the splash target 29a, 29b).

In addition to the above conditions, film formation was carried out under the same conditions as those of Experimental Examples 1 to 5, and a sample of each experimental example in which a tantalum carbide film having a thickness of 4 μm was formed on the substrate S was obtained. When the same evaluations as in Experimental Examples 1 to 5 were carried out for each of the obtained samples, it was confirmed that the same tendency was observed.

<Experimental Examples 11 to 15>

The sputtering power density of the targets 49a and 49b made of carbon (C) in the region 40 was changed to 14 W/cm ² . Further, the targets 29a and 29b are changed to be made of tantalum carbide (SiC). Further, the sputtering power density of the targets 29a and 29b was changed to 11 W/cm ² (corresponding to about 0.8 times the power density of the targets 49a and 49b made of carbon (C).

In addition to the above conditions, film formation was carried out under the same conditions as those of Experimental Examples 1 to 5, and a sample of each experimental example in which a tantalum carbide film having a thickness of 4 μm was formed on the substrate S was obtained. Further, when the same evaluations as in Experimental Examples 1 to 5 were carried out for each of the obtained samples, it was confirmed that the same tendency was observed.

1. . . Sputtering device

11. . . Vacuum container

12. . . Compartment wall

13. . . Substrate holder

14. . . Compartment wall

15. . . Vacuum pump

15a. . . Pipeline

16. . . Compartment wall

17. . . motor

20. . . Film forming process area

21a. . . Magnetron sputtering electrode

21b. . . Magnetron sputtering electrode

twenty three. . . AC power

twenty four. . . transformer

25. . . Flow controller

26. . . Gas cylinder

29a. . . Target

29b. . . Target

40. . . Film forming process area

41a. . . Magnetron sputtering electrode

41b. . . Magnetron sputtering electrode

43. . . AC power

44. . . transformer

45. . . Flow controller

46. . . Gas cylinder

49a. . . Target

49b. . . Target

60. . . Reaction process area

67. . . Flow controller

68. . . Gas cylinder

80. . . Plasma source

81. . . Box

83. . . Dielectric plate

85a. . . antenna

85b. . . antenna

87. . . Matching box

89. . . High frequency power supply

S. . . Substrate

S1. . . step

S2. . . step

S3. . . step

S4. . . step

S21. . . step

S22. . . step

S23. . . step

Z. . . Rotation axis

Fig. 1 is a partial cross-sectional view showing an example of a film forming apparatus which realizes the method of the present invention.

Fig. 2 is a partial longitudinal sectional view taken along line II-II of Fig. 1.

Fig. 3 is a flow chart showing the flow of a film forming method using the film forming apparatuses of Figs. 1 and 2.

1. . . Sputtering device

11. . . Vacuum container

12. . . Compartment wall

13. . . Substrate holder

14. . . Compartment wall

15. . . Vacuum pump

15a. . . Pipeline

16. . . Compartment wall

20. . . Film forming process area

21a. . . Magnetron sputtering electrode

21b. . . Magnetron sputtering electrode

twenty three. . . AC power

twenty four. . . transformer

25. . . Flow controller

26. . . Gas cylinder

29a. . . Target

29b. . . Target

40. . . Film forming process area

41a. . . Magnetron sputtering electrode

41b. . . Magnetron sputtering electrode

43. . . AC power

44. . . transformer

45. . . Flow controller

46. . . Gas cylinder

49a. . . Target

49b. . . Target

60. . . Reaction process area

67. . . Flow controller

68. . . Gas cylinder

80. . . Plasma source

81. . . Box

83. . . Dielectric plate

87. . . Matching box

89. . . High frequency power supply

Claims (10)

A method for forming a tantalum carbide film, which is a method for forming a tantalum carbide film on a moving substrate while independently controlling the splashing of the target and the exposure of the plasma in a vacuum state, characterized in that the inert gas is Under the atmosphere, two targets selected from the group consisting of a ruthenium target, a carbon target and a ruthenium carbide target are respectively splashed, and an intermediate film containing ruthenium and carbon is formed on the substrate; and the intermediate film is exposed to an inert gas. The plasma generated in the atmosphere of the mixed gas with hydrogen is converted into an ultrathin film, and thereafter the formation of the intermediate film and the film conversion of the ultrathin film are repeated on the ultrathin film. A film forming method of a tantalum carbide film, wherein in the film forming method, a film forming apparatus is used to form a tantalum carbide film on a moving substrate, wherein the film forming apparatus converts a reaction process region in a single vacuum container The plurality of film forming process regions are each spatially separated and disposed, and the processing in each region is independently controlled, and is characterized in that, in an inert gas atmosphere, each of the film forming process regions is selected from the group consisting of a target and a carbon target. Any one of the two targets in the material and the niobium carbide target is splashed, and an intermediate film containing tantalum and carbon is formed on the substrate; the intermediate film is exposed to the inert gas and hydrogen in the reaction process region The plasma generated in the atmosphere of the mixed gas is converted into an ultra-thin film, and thereafter the formation of the intermediate film and the film conversion of the ultra-thin film are repeated on the ultra-thin film. A film forming method of a tantalum carbide film according to claim 1 or 2, wherein the mixed gas contains hydrogen in a concentration of 3 to 20%. The film forming method of the tantalum carbide film according to claim 1 or 2, wherein in the case of using the tantalum target and the carbon target, the energy density of the target is splashed 5 times. The left and right energy density splashes the carbon target. A method of forming a tantalum carbide film according to claim 4, wherein the target of the tantalum is splashed at an energy density of about 1.7 W/cm ² . The film forming method of the tantalum carbide film according to claim 1 or 2, wherein in the case of using the tantalum target and the tantalum carbide target, 2.5 of the energy density of the target is splashed. The energy density of about double times is used to splash the target of the tantalum carbide. A film forming method for a tantalum carbide film according to claim 6, wherein the target of the tantalum is splashed at an energy density of about 3.5 W/cm ² . The film forming method of the tantalum carbide film according to claim 1 or 2, wherein in the case of using the carbon target and the niobium carbide target, 0.8 of the energy density of the carbon target is splashed. The energy density of about double times is used to splash the target of the tantalum carbide. The film forming method of the tantalum carbide film according to Item 8 of the invention is characterized in that the carbon target is splashed at an energy density of about 14 W/cm ² . An optical substrate formed on a substrate in a film having a film of tantalum carbide on a substrate, which is formed on the substrate by a method according to any one of claims 1 to 9, at a wavelength of 650 nm to 700 nm. through The light transmittance is 70% or more, and the Vickers hardness HV on the film side is 1300 or more.