Film formation method

Abstract

A film formation method that arranges within a chamber a target made of yttrium and a base material on which a film is to be formed, introduces at least oxygen into the chamber, applies a predetermined bias voltage to the base material, and forms a yttrium oxide film on the base material by evaporating the surface of the target in the oxygen, wherein the bias voltage is set so that the porosity of the film will be 0.5% or less to form the yttrium oxide film having a thickness of 40 μm or more.

Description

Film forming method

[0001] The present invention relates to a film forming method for forming a film having excellent plasma resistance on the surface of a substrate.

[0002] Conventionally, there has been a demand for materials with excellent plasma resistance for components used in environments exposed to plasma, such as semiconductor manufacturing equipment. Patent Document 1 discloses a method for obtaining such a material by using yttrium oxide (Y ２ O ３ Patent Document 2 discloses a technique for forming an yttrium oxide film on the surface of a substrate by an ion plating method using yttrium oxide as a raw material. Patent Document 2 also discloses a technique for forming an yttrium oxide film by a reactive sputtering method.

[0003] JP 2007-290933 A International Publication No. 2019 / 26818

[0004] In the methods described in Patent Documents 1 and 2, the deposition rate of the yttrium oxide film is relatively slow, so in order to obtain a more practical deposition rate, deposition by an arc ion plating method (vacuum arc method) is desirable. However, when the present inventors attempted to form an yttrium oxide film by the arc ion plating method, they discovered a new problem: as the film thickness increases, the porosity increases, and the quality of the deposited film decreases.

[0005] An object of the present invention is to provide a film forming method that can stably form an yttrium oxide film of a predetermined thickness on a substrate by arc ion plating.

[0006] In order to achieve the above object, the inventors of the present application have conducted extensive experiments using an arc ion plating method to form an yttrium oxide film, and as a result have discovered a new film formation method.

[0007] A film formation method according to the present invention is a film formation method for forming an yttrium oxide film on a substrate by an arc ion plating method, and includes the steps of placing a target made of yttrium and the substrate in a chamber, introducing at least oxygen into the chamber, applying a predetermined bias voltage to the substrate, and evaporating the surface of the target in the oxygen to form an yttrium oxide film on the substrate, wherein the bias voltage is set so that the porosity of the film is 0.5% or less, and the yttrium oxide film is formed to a thickness of 40 μm or more.

[0008] A film formation method according to the present invention is a film formation method for forming an yttrium oxide film on a substrate by an arc ion plating method, the method comprising the steps of: placing a target made of yttrium and the substrate in a chamber; introducing at least oxygen into the chamber; applying a predetermined bias voltage to the substrate; and evaporating the surface of the target in the oxygen to form an yttrium oxide film on the substrate; and ３ and setting the bias voltage so as to form the yttrium oxide film having a thickness of 40 μm or more.

[0009] Furthermore, a film formation method according to the present invention is a film formation method for forming an yttrium oxide film on a substrate, which is the object of the film formation, by an arc ion plating method, and includes the steps of placing a target made of yttrium and the substrate in a chamber, introducing at least oxygen into the chamber, applying a predetermined bias voltage to the substrate, and evaporating the surface of the target in the oxygen to form an yttrium oxide film on the substrate, wherein the bias voltage is set so that the hardness of the film is 9 GPa or more, and the yttrium oxide film is formed to a thickness of 40 μm or more.

[0010] FIG. 1 is a schematic diagram showing the general configuration of a film formation apparatus for performing a film formation method according to one embodiment of the present invention. FIG. 2 is a schematic diagram for calculating stress from film warpage. FIG. 3 is a cross-sectional photograph of an yttrium oxide film formed on a substrate in an example of the present invention. FIG. 4 is a graph showing the relationship between the distance from the interface of the film with the substrate and the porosity of the film. FIG. 5 is a graph showing the relationship between the porosity of the film and the etching rate. FIG. 6 is a graph showing the relationship between the bias voltage applied during film formation and the porosity of the film. FIG. 7 is a graph showing the relationship between the bias voltage applied during film formation and the density of the film. FIG. 8 is a graph showing the relationship between the density of the film and the etching rate. FIG. 9 is a graph showing the relationship between the bias voltage applied during film formation and the hardness of the film. FIG. 10 is a graph showing the relationship between the hardness of the film and the etching rate. FIG. 11 is a graph showing the relationship between the bias voltage applied during film formation and the stress of the film.

[0011] An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. Fig. 1 is a schematic diagram showing the general configuration of a film formation apparatus 10 for performing a film formation method according to this embodiment. The film formation method according to this embodiment is a method for forming a coating having excellent plasma resistance on the surface of a substrate.

[0012] 1 is an example of a film formation apparatus for carrying out the film formation method according to this embodiment, and the film formation apparatus for carrying out the film formation method is not limited to the one shown in Fig. 1. This film formation apparatus 10 is an apparatus that uses a physical vapor deposition (PVD) method to form a film on the surface of a workpiece W (substrate) placed in a vacuum chamber 12. Examples of this film formation apparatus 10 include an AIP (Arc Ion Plating) apparatus that forms a film using an arc ion plating method and a sputtering apparatus that forms a film using a sputtering method.

[0013] The film formation apparatus 10 is an arc ion plating apparatus and includes a vacuum chamber 12, a rotary table 14, a plurality of substrate holders 16, a bias power supply 18, a target 20 as an evaporation source, an arc power supply 22, a heater 24, an argon tank 30, an oxygen tank 32, a vacuum pump P, and a controller 50.

[0014] The vacuum chamber 12 accommodates a turntable 14 and a plurality of substrate holders 16 arranged on the turntable 14. The interior of the vacuum chamber 12 (i.e., the space accommodating the turntable 14 and the plurality of substrate holders 16) is maintained in a vacuum or near-vacuum state by a vacuum pump P during various processes including the film formation process. The vacuum chamber 12 is provided with a gas inlet 12A and an exhaust outlet 12B.

[0015] The turntable 14 has a disk shape with a centerline extending in the vertical direction in Fig. 1 . The turntable 14 is disposed within the vacuum chamber 12. During the film formation process, the turntable 14 rotates around its centerline while supporting a plurality of substrate holders 16. The turntable 14 may further include a turntable on which each of the plurality of substrate holders 16 is individually disposed so that each of the plurality of substrate holders 16 can rotate on its own axis. The number of substrate holders 16 is not limited to two as shown in Fig. 1 .

[0016] Each of the plurality of substrate holders 16 supports a workpiece W (substrate) on which a film is to be formed. In this embodiment, the workpiece W is disposed on the outer circumferential surface of the substrate holder 16. Note that only some of the workpieces W are shown in FIG. 1 .

[0017] In this embodiment, the workpiece W is made of an A6061 alloy (Al alloy) (also referred to as an Al base material) and is a square plate piece measuring 20 mm x 20 mm. However, the material and shape of the workpiece W are not limited to this.

[0018] Each of the substrate holders 16 is made of a conductive material, such as stainless steel.

[0019] The plurality of substrate holders 16 are arranged at equal intervals in the circumferential direction of the turntable 14. In this state, the center line of each of the plurality of substrate holders 16 is parallel to the center line of the turntable 14.

[0020] The bias power supply 18 applies a negative bias voltage to each of the plurality of substrate holders 16 via the rotary table 14. In the present embodiment, as an example, the bias power supply 18 intermittently applies a negative bias voltage to each of the plurality of substrate holders 16. In other words, the bias power supply 18 is a pulse power supply. When the resistance of the coating formed on the workpiece W is relatively high, applying a DC bias as the bias voltage may cause a problem of charge accumulation (charge-up) due to incident ions. On the other hand, by applying a pulse voltage as the bias voltage as in the present embodiment, this problem can be prevented even when the resistance of the coating formed on the workpiece W is relatively high. More specifically, the charge-up problem can be prevented by switching the bias between the negative side and 0 V or the positive side as the pulse voltage on the order of μS or mS.

[0021] Note that the bias power supply 18 does not apply a bias when it is not applying a negative bias voltage during the film formation process. Alternatively, the bias power supply 18 can alternately apply a negative bias voltage and a positive bias voltage to each of the plurality of substrate holders 16. The absolute value of the negative bias voltage is greater than the absolute value of the positive bias voltage.

[0022] If a negative bias voltage and a positive bias voltage are applied alternately, the bias power supply 18 may be, for example, an alternating current power supply (AC power supply) or a radio frequency power supply (RF power supply).The bias power supply 18 may also apply a DC bias, as will be described in detail later.

[0023] The target 20 is a disk-shaped member made of yttrium. As an example, the target 20 is a disk having a diameter of 100 mm.

[0024] The arc power supply 22 is a DC power supply that functions as a discharge power supply that generates a vacuum arc discharge in the target 20 placed in the vacuum chamber 12. In this case, the target 20 functions as a cathode in the discharge. Meanwhile, as shown in FIG. 1, the vacuum chamber 12 functions as an anode in the discharge. The target 20 emits evaporated yttrium ions from its surface upon receiving the discharge generated by the arc power supply 22. The arc power supply 22, together with the target 20, constitutes an arc evaporation source.

[0025] The heater 24 is provided in the vacuum chamber 12 and generates heat when supplied with current from a heater power supply (not shown). As a result, the environment in the vacuum chamber 12 and the workpiece W are heated.

[0026] The argon tank 30 contains argon and supplies argon gas to the vacuum chamber 12. Similarly, the oxygen tank 32 contains oxygen and supplies oxygen to the vacuum chamber 12. The amount of gas supplied from these tanks is controlled by adjusting the opening of a regulator (not shown) in response to a command from the controller 50. In another embodiment, the amount of gas supplied may be manually adjusted by an operator.

[0027] The vacuum pump P creates a vacuum in the internal space of the vacuum chamber 12 through the exhaust port 12B (evacuation).

[0028] In addition to the regulators, the controller 50 controls the vacuum pump P, the bias power supply 18, the arc power supply 22, and various voltages or currents of the heater 24, as well as the rotation of the rotary table 14, etc.

[0029] Next, an example of the film formation method according to this embodiment will be described. In the following description, oxygen may be represented as O and yttrium as Y. The present invention is not limited to the scope of the following example. To carry out the film formation method, as shown in FIG. 1, a target 20 and a workpiece W are installed in a film formation apparatus 10, and a vacuum chamber 12 is evacuated to a vacuum state by a vacuum pump P.

[0030] Next, after preheating inside the vacuum chamber 12 by the heater 24, argon gas is introduced from the argon tank 30 into the vacuum chamber 12 through the gas inlet 12A, and as a pretreatment, the surface of the workpiece W is bombarded with argon gas ions. Here, bombardment means generating heavy inert gas ions such as argon ions by plasma discharge, and irradiating the workpiece W with these ions to heat and sputter the surface of the workpiece W, thereby cleaning moisture and contaminants from the surface.

[0031] After the above bombardment, pure oxygen gas is introduced at a flow rate of about 240 sccm so that the pressure in the chamber becomes about 1 Pa. In another embodiment, instead of pure oxygen gas, Ar—O ２ A mixed gas (e.g., Ar 450 sccm, oxygen 50 sccm) may be introduced so that the pressure inside the chamber becomes approximately 2 Pa. In order to maintain stable discharge, it is desirable to set the total pressure inside the chamber in the range of 0.6 Pa to 4 Pa.

[0032] Next, while the target 20 functions as a cathode, a discharge is generated in the vacuum chamber 12, and an yttrium oxide film is formed on the workpiece W. During this process, the temperature of the workpiece W is approximately 300°C (200°C to 400°C), the arc current is in the range of 100 A to 125 A, and the voltage applied to the workpiece W is a unipolar pulse (pulse waveform) with a frequency of 200 kHz and a duty of 56% or a DC bias (direct current voltage), with the average voltage varied between 10 and 100 V. The thickness of the yttrium oxide film formed on the workpiece W is approximately 10 to 100 μm. As mentioned above, an example of the workpiece W is A6061Al (20 mm x 20 mm square piece). The amount of oxygen in the formed yttrium oxide film is controlled by changing the pressure of the oxygen flowing into the chamber, i.e., the oxygen partial pressure (oxygen flow rate).

[0033] Next, a method for evaluating the yttrium oxide film formed on the workpiece W will be described together with its indicators.

[0034] (1) Evaluation of porosity A test piece (workpiece W made of an Al substrate) on which a coating was formed was cut along the film thickness direction and embedded in a resin for evaluation. The cross section was observed from the cross-sectional direction using a scanning electron microscope (SEM). Then, using an SEM image at a magnification of 500 times, the voids in the coating observable on the cross section were calculated by image analysis. In this case, as an example, ImageJ 1.50b was used as the analysis software. The image analysis procedure is as follows.

[0035] (Step 1) The analysis portion is cut out from the image. In this case, a region approximately 20 μm deep from the surface of the film is cut out. (Step 2) The image is binarized. The conditions for binarization were a threshold value of 110 and 256 gradations. (Step 3) The defect (void) area is calculated.

[0036] (2) Evaluation of Film Stress As shown in FIG. 2, the amount of warpage of a sample Al plate was measured over a length of 10 mm using a stylus surface roughness meter, with an yttria film (yttrium oxide film) formed on a workpiece W of 20 × 20 × 5 mm, and the stress σ was calculated using the following Stoney formula (1).

[0037]

[0038] In Equation 1 and FIG. 2, σ is stress, E is Young's modulus of the substrate 72 GPa, bs is substrate thickness 5 mm, δs is deflection amount mm, ls is cantilever length 5 mm, and ds is film thickness μm.

[0039] (3) Evaluation of film density A yttria film with a thickness of about 100 μm was formed on an Al plate of 30 × 30 × 5 mm, and the weight increase of the substrate before and after film formation was measured. ２ ) and calculate the volume of the film, and then calculate its density.

[0040] (4) Evaluation of Hardness of Coating The Al substrate on which the coating was formed was cut and embedded in resin. Using a nanoindenter, the substrate was indented in the thickness direction at 10 μm intervals from the cross-sectional direction, and a load-unload curve was measured at 10 points using an indenter with a Berkovich-type indenter at a maximum load of 5 mN. Tip curvature correction according to Oliver et al. (W.C. Oliver, G.m. Pharr; J. Mater. Res, 7, 1564 (1992) or J.B. Pechica, W.C. Oliver; Physica Scripta, T19, 61 (1987)) was performed, and the average hardness of the cross section was measured.

[0041] (5) Evaluation of Etching Resistance The etching resistance of the formed film was evaluated using the following equipment and conditions: Equipment used: ICP etching equipment Gas composition: Ar:CHF ３ :O ２ = 130:14:5 (flow ratio) Pressure 9 Pa Power Coil 13.56 MHz, 1 kW, Sample 13.56 MHz, 0.9 kW (Vdc approx. 950 V)

[0042] Figure 3 shows a cross-sectional SEM image of an yttrium oxide film formed at a bias voltage of 10 V. As can be seen from Figure 3, the thicker the film (the region closer to the surface), the more voids there are in the film. The formation of these voids is thought to be due to nodule growth centered around particles (molten particles and macroparticles scattered from the target) specific to the vacuum arc method.

[0043] Figure 4 is a graph showing the relationship between the distance from the interface with the substrate in the thickness direction and the porosity in that region for a coating formed at a bias voltage of 10 V. This porosity corresponds to the result of dividing the interior of the coating into 20 μm intervals and calculating the porosity in each section. The porosity at a distance of 10 μm from the interface represents the average porosity in the range from 0 to 20 μm, with the interface being set at 0. Similarly, the plot for 70 μm in Figure 4 represents the average porosity in the range from 60 to 80 μm. As shown in Figure 4, the porosity increases with increasing film thickness, and in particular, it can be seen that the porosity reaches approximately 0.5% when the film thickness (distance from the interface) exceeds 40 μm. As shown in Figures 3 and 4, almost no voids are observed near the interface between the coating and the substrate, but the porosity increases in the upper part of the coating.

[0044] Fig. 5 is a graph showing the relationship between the porosity of the film and the plasma etching rate. As shown in Fig. 5, the etching rate increases as the porosity in the film increases, and by keeping the porosity at 0.5% or less, the etching rate can be kept at 1.75 µm / hr or less. In semiconductor manufacturing equipment, which is an example of the application field of the present invention, etching processes using plasma are widely used, and in recent years, as the semiconductor device structure has become more complex, etching times have become longer, which has led to problems of etching, damage, and wear of components inside the equipment by plasma. For this reason, materials that are difficult to etch with plasma (i.e., have a small etching rate) (e.g., Y ２ O ３ Materials with low etching rates are suitable as protective materials for semiconductor manufacturing equipment components because they are less likely to wear down due to etching, meaning they last longer before needing to be replaced (long life), and they also emit less pollutants.

[0045] FIG. 6 is a graph showing the relationship between bias voltage and porosity, showing the results for pulse bias (AC bias) and DC bias, respectively. The porosity was also measured in a region approximately 20 μm from the surface of a film with a thickness of 50 μm or more. As shown in FIG. 6, with pulse bias, by setting the bias voltage during film formation to 25 V or more, the porosity within 20 μm from the surface of the film can be kept to 0.5% or less, even for thick films with a thickness of 50 μm or more. Similarly, with DC bias, by setting the bias voltage during film formation to 25 V or more, the porosity can be kept to 0.5% or less. When the applied voltage is a pulse voltage, the bias voltage can be calculated by time averaging.

[0046] Fig. 7 is a graph showing the relationship between the bias voltage applied during film formation and the density of the film. Fig. 8 is a graph showing the relationship between the density of the film and the etching rate. As shown in Figs. 7 and 8, it has been newly discovered that the etching rate changes with an increase in the film density measured from the change in weight of the substrate, as well as the porosity of the film. In order to keep the etching rate low, the density of the film should be 5 g / cm. ３ It turns out that it's better to have more than that.

[0047] Fig. 9 is a graph showing the relationship between the bias voltage applied during film formation and the hardness of the film. Fig. 10 is a graph showing the relationship between the hardness of the film and the etching rate. As shown in Figs. 9 and 10, it has been newly discovered that the etching rate changes not only with the porosity of the film but also with an increase in the hardness of the film measured from the cross-sectional direction. Similarly, it is found that in order to keep the etching rate low, it is best for the average hardness of the film to be 9 GPa or more.

[0048] Fig. 11 is a graph showing the relationship between the bias voltage applied during film formation and the stress of the film. As shown in Fig. 11, increasing the bias voltage decreases the porosity of the film and the etching rate due to plasma irradiation, while increasing the residual stress generated in the film. For this reason, it is preferable to set the bias voltage to less than 75 V.

[0049] As described above, the film formation method according to this embodiment is a method for forming an yttrium oxide film on a substrate by arc ion plating, which includes placing a target made of yttrium and the substrate in a chamber, introducing at least oxygen into the chamber, applying a predetermined bias voltage to the substrate, evaporating the surface of the target in the oxygen to form an yttrium oxide film on the substrate, and setting the bias voltage so that the porosity of the film is 0.5% or less, thereby forming an yttrium oxide film having a thickness of 40 μm or more.

[0050] According to this method, it is possible to stably form an yttrium oxide film at a practical film formation rate while suppressing the porosity of the film by using the bias voltage as a control parameter.

[0051] In other words, the film forming method according to this embodiment includes the steps of: placing a target made of yttrium and the substrate in a chamber; introducing at least oxygen into the chamber; applying a predetermined bias voltage to the substrate; evaporating the surface of the target in oxygen to form an yttrium oxide film on the substrate; and depositing an yttrium oxide film on the substrate so that the density of the film is 5 g / cm. ３ and setting the bias voltage so as to form an yttrium oxide film having a thickness of 40 μm or more. This method also has the same effects as those described above.

[0052] Furthermore, in other words, the film formation method includes placing a target made of yttrium and the substrate in a chamber, introducing at least oxygen into the chamber, applying a predetermined bias voltage to the substrate, evaporating the surface of the target in the oxygen to form an yttrium oxide film on the substrate, and setting the bias voltage so that the hardness of the film is 9 GPa or more, thereby forming an yttrium oxide film having a thickness of 40 μm or more. This method can also achieve the same effects as those described above.

[0053] These methods form an yttrium oxide film on a substrate by arc ion plating at a practical film formation rate, and have a common technical effect of keeping the etching rate of the film low.

[0054] When the thickness of the yttrium oxide film is 50 μm or more, the effect of applying the bias voltage is more pronounced, and when the thickness is 80 μm or more, the effect is even more pronounced.

[0055] The porosity is more preferably 0.3% or less, and even more preferably 0.1% or less.

[0056] Here, it is desirable that the bias voltage be set to an average of 25 V or more. Furthermore, it is more desirable that the bias voltage be set to an average of 30 V or more, and even more desirable that the bias voltage be set to an average of 50 V or more. On the other hand, as mentioned above, if the bias voltage is set to an average of 75 V or more, stress increases, so it is preferable that the bias voltage be set to less than 75 V. In this case, as shown in FIG. 6, by setting the bias voltage to 40 V or more, the porosity can be suppressed regardless of whether a pulse bias or a DC bias is used. It can be said that the DC bias has a constant value compared to a pulse bias.

[0057] To achieve a practical film formation rate, it is desirable to form the film using an arc ion plating method rather than a conventional ion plating method or reactive sputtering method. For example, conventional etching equipment typically uses a film with a thickness of 100 μm or more, and the slow film formation rate of ion plating or sputtering methods is an issue. However, the inventors have discovered that an inherent problem with arc ion plating, which is expected to achieve a high film formation rate, is that the porosity increases as the film thickness increases, particularly when forming films with a thickness of 40 μm or more and 100 μm or less. The inventors have newly discovered that this problem can be solved by adjusting the bias voltage. In the above-mentioned thickness range, it is difficult to achieve a practical film formation rate while reducing the porosity using conventional sputtering methods.

[0058] The desirable lower limit of the bias voltage varies somewhat depending on the apparatus, but the inventors have confirmed that by setting the bias voltage to 25 V or higher, the above-mentioned variations can be absorbed and good film formation can be achieved.

[0059] In the present invention, the yttrium oxide film is a film containing Y ２ O ３ and Y are mixed together, and Y ２ O ３ As a result of changing the ratio of Y to O in the film, the ratio of Y to O in the film changes. ２ O ３ Films in which Y and O are mixed together are collectively referred to as "yttrium oxide films." Note that the ratio of Y to O in this case is an atomic ratio.

[0060] The yttrium oxide film obtained by the film forming method according to the present invention can be widely applied to members exposed to plasma, such as semiconductor manufacturing equipment.

[0061] These are merely examples, and the present invention should not be construed as being limited in any way by the description of the above-described embodiments. In the present invention, the substrate is not limited to one made of an insulating material, but may be made of a conductive material. In the present invention, the manner in which a negative bias voltage and a positive bias voltage, or a negative bias and no bias (0 V), are alternately applied is not limited to the pulsed form described in the above-described embodiments, and may be, for example, a sinusoidal, rectangular, or triangular waveform. Furthermore, if the arc current is too small, the discharge will be unstable, and if it is too large, the target may be heated. Therefore, it is desirable to set the arc current in the range of 50 A to 200 A for a target with a diameter of approximately 100 mm.

[0062] A film formation method according to a first aspect of the present invention is a film formation method for forming an yttrium oxide film on a substrate by an arc ion plating method, comprising: placing a target made of yttrium and the substrate in a chamber; introducing at least oxygen into the chamber; applying a predetermined bias voltage to the substrate; evaporating the surface of the target in the oxygen to form an yttrium oxide film on the substrate; setting the bias voltage so that the porosity of the film is 0.5% or less; and forming the yttrium oxide film to a thickness of 40 μm or more.

[0063] When an yttrium oxide film is formed by arc ion plating using yttrium discharge in an oxygen atmosphere, the porosity of the film tends to increase as the film thickness increases. However, by adjusting the bias voltage applied to the substrate during film formation, the porosity can be reduced even for yttrium oxide films with a thickness of 40 μm or more. In particular, by keeping the porosity at 0.5% or less, the etching rate can be reduced.

[0064] A film formation method according to a second aspect of the present invention is a film formation method for forming an yttrium oxide film on a substrate by an arc ion plating method, the method comprising the steps of: placing a target made of yttrium and the substrate in a chamber; introducing at least oxygen into the chamber; applying a predetermined bias voltage to the substrate; and evaporating the surface of the target in the oxygen to form an yttrium oxide film on the substrate; and ３ and setting the bias voltage so as to form the yttrium oxide film having a thickness of 40 μm or more.

[0065] Furthermore, a film formation method according to a third aspect of the present invention may be a film formation method for forming an yttrium oxide film on a substrate, which is an object to be formed with a film, by an arc ion plating method, comprising: placing a target made of yttrium and the substrate in a chamber; introducing at least oxygen into the chamber; applying a predetermined bias voltage to the substrate; evaporating the surface of the target in the oxygen to form an yttrium oxide film on the substrate; setting the bias voltage so that the hardness of the film is 9 GPa or more; and forming the yttrium oxide film to a thickness of 40 μm or more.

[0066] A method according to a fourth aspect of the present invention may be the method according to any one of the first to third aspects, further comprising setting the bias voltage to be 25 V or more on average.

[0067] According to this method, the bias voltage to be adjusted is set to 25 V or more on average, so that the porosity can be stably reduced.

[0068] A method according to a fifth aspect of the present invention may be the method according to any one of the first to fourth aspects, further comprising setting the bias voltage to be less than 75V on average.

[0069] According to this method, it is possible to prevent the stress acting on the film from becoming too large.

[0070] A method according to a sixth aspect of the present invention may be the method according to any one of the first to fifth aspects, wherein the bias voltage has a pulse waveform.

[0071] A method according to a seventh aspect of the present invention may be the method according to any one of the first to fifth aspects, wherein the bias voltage is a constant value.

Claims

1. A film-forming method for forming a yttrium oxide film on a substrate to be filmed by an arc ion plating method, comprising: disposing a target made of yttrium and the substrate in a chamber; introducing at least oxygen into the chamber; applying a predetermined bias voltage to the substrate; evaporating the surface of the target in oxygen to form a yttrium oxide film on the substrate, wherein the bias voltage is set so that the porosity of the film is 0.5% or less, and the yttrium oxide film having a thickness of 40 μm or more is formed.

2. A film forming method for forming a yttrium oxide film on a substrate to be formed with a film by an arc ion plating method, comprising: disposing a target made of yttrium and the substrate in a chamber; introducing at least oxygen into the chamber; applying a predetermined bias voltage to the substrate; evaporating the surface of the target in oxygen to form a yttrium oxide film on the substrate, wherein the bias voltage is set so that the density of the film is 5 g / cm ３ or more, and forming the yttrium oxide film having a thickness of 40 μm or more.

3. A film-forming method for forming a yttrium oxide film on a substrate to be filmed by an arc ion plating method, comprising: disposing a target made of yttrium and the substrate in a chamber; introducing at least oxygen into the chamber; applying a predetermined bias voltage to the substrate; evaporating the surface of the target in oxygen to form a yttrium oxide film on the substrate, wherein the bias voltage is set so that the hardness of the film is 9 GPa or more, and the yttrium oxide film having a thickness of 40 μm or more is formed.

4. The film-forming method according to any one of claims 1 to 3, further comprising setting the bias voltage to an average of 25 V or more.

5. The film-forming method according to any one of claims 1 to 3, further comprising setting the bias voltage to an average of less than 75 V.

6. The film-forming method according to any one of claims 1 to 3, wherein the waveform of the bias voltage is a pulse waveform.

7. The film-forming method according to any one of claims 1 to 3, wherein the bias voltage is a constant value.

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