Yttrium oxide film and method for forming the film

Abstract

This invention provides a yttrium oxide coating and a method for forming the coating, in which a decrease in plasma resistance due to abnormal growth originating from foreign matter is suppressed. [Solution] In a yttrium oxide film formed on a substrate, the average ratio of the major axis to the minor axis when each of the multiple particles, mainly composed of metallic yttrium, present in the film is approximated by an ellipse in a cross-section including the thickness direction of the film is greater than 1.5.

Description

Technical Field

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[0001] The present invention relates to a yttrium oxide film excellent in plasma resistance and a method for forming the same.

Background Art

[0002] Conventionally, for members used in an environment exposed to plasma, such as semiconductor manufacturing equipment, materials excellent in plasma resistance have been demanded. In Patent Document 1, in order to obtain such a material, a technique for forming a yttrium oxide film on the surface of a substrate by an ion plating method using yttrium oxide (Y2O3) as a raw material is disclosed. Further, in Patent Document 2, a technique for forming a yttrium oxide film by a reactive sputtering method is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the techniques described in Patent Documents 1 and 2, when particles such as foreign substances are present in the film during the formation of the yttrium oxide film, abnormal growth (nodules) starting from the particles occurs, voids are generated in the film, and the airtightness, that is, the plasma resistance, is impaired.

[0005] The present invention has been conceived in view of the above problems, and an object thereof is to provide a yttrium oxide film in which a decrease in plasma resistance due to abnormal growth starting from particles such as foreign substances is suppressed, and a method for forming the same.

Means for Solving the Problems

[0006] The present invention provides a yttrium oxide film formed on a substrate, wherein, in a cross-section including the thickness direction of the film, the average ratio of the major axis to the minor axis of each of the multiple particles, mainly composed of metallic yttrium, present in the film is greater than 1.5 when each particle is approximated by an ellipse.

[0007] This configuration prevents abnormal growth (nodule growth) from occurring in the coating, which originates from particles and forms voids, thereby preventing a decrease in plasma resistance.

[0008] In the above configuration, the coating may have a thickness of 30 μm or more.

[0009] The nodule growth and void formation based on the particles described above become more pronounced when the film thickness increases to 30 μm or more. With this configuration, by focusing on the flattening ratio of the particles, even within this thickness range, abnormal growth originating from the particles within the film and the formation of voids can be suppressed, thereby preventing a decrease in plasma resistance.

[0010] The present invention provides a method for forming the yttrium oxide film described above, comprising appropriately setting the distance between the target and the substrate, and then melting and evaporating the surface of the target by an arc ion plating method to form the film on the substrate.

[0011] Particle contamination is particularly pronounced in arc ion plating, where melting and scattering of the target due to arc discharge are unavoidable. According to this method, even in such cases, abnormal growth and void formation caused by foreign particles in the coating are suppressed, thereby preventing a decrease in plasma resistance. Specifically, by appropriately setting the distance between the target and the workpiece, this method allows for the formation of flattened particle shapes with a major-axis / minor-axis ratio exceeding 1.5. In arc ion plating, particles (molten metal) scattered from the target experience a temperature decrease due to radiation as they travel from the target to the substrate. If the distance from the target to the substrate is long, the particles cool and solidify before reaching the substrate, becoming spherical and adhering to it. In this case, voids are created between the substrate and the particles, and nodules are formed starting from these voids. On the other hand, if the distance from the target to the substrate is short, the particles are more likely to reach the substrate in a molten state, deform along the shape of the substrate, and become flattened. In this case, voids like those formed by the spherical particles are less likely to occur, thus reducing the likelihood of nodule growth.

[0012] The above method may further include setting the distance between the target and the substrate during film formation so that the porosity of the film is 0.2% or less.

[0013] According to this method, a dense yttrium oxide film can be formed by setting the porosity of the film to 0.2% or less.

[0014] The above method may further include setting the shortest distance between the target and the substrate during film formation to 300 mm or less. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a yttrium oxide coating in which a decrease in plasma resistance due to abnormal growth originating from particles such as foreign matter is suppressed, and a method for forming the same coating. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic diagram showing a schematic configuration of a film-forming apparatus for forming a yttrium oxide film according to an embodiment of the present invention. [Figure 2A] Figure 2A is a magnified cross-sectional photograph showing particles in the yttrium oxide film. [Figure 2B] Figure 2B is a magnified cross-sectional photograph showing particles in the yttrium oxide film. [Figure 3A] Figure 3A is a cross-sectional photograph of a substrate and a yttrium oxide film. [Figure 3B] Figure 3B is a cross-sectional photograph of a substrate and a yttrium oxide film. [Figure 4A] Figure 4A is a diagram showing the result of applying image analysis to the yttrium oxide film region of Figure 3A. [Figure 4B] Figure 4B is a diagram showing the result of applying image analysis to the yttrium oxide film region of Figure 3B. [Figure 5] Figure 5 is a graph showing the relationship between the aspect ratio of particles and the porosity of the film. [Figure 6] Figure 6 is a graph showing the relationship between the TS distance and the aspect ratio of particles. [Figure 7] Figure 7 is a graph showing the relationship between the film thickness of the film and the porosity.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 is a schematic diagram showing a schematic configuration of a film-forming apparatus 10 for forming a yttrium oxide film according to the present embodiment. The method for forming a yttrium oxide film according to the present embodiment is a method for forming a film excellent in plasma resistance on the surface of a substrate. The formed yttrium oxide film can be applied, for example, to a member exposed to plasma in a semiconductor manufacturing apparatus or the like.

[0018] Note that the film deposition apparatus 10 shown in Figure 1 is an example of a film deposition apparatus for carrying out the film deposition method according to this embodiment, and the film deposition apparatus for carrying out the film deposition method is not limited to the one shown in Figure 1. This film deposition apparatus 10 is an apparatus that deposits a film on the surface of a workpiece W (substrate) placed in a vacuum chamber 12 using the physical vapor deposition method (PVD method). This film deposition apparatus 10 may include an AIP (Arc Ion Plating) apparatus that performs film deposition using the arc ion plating method, or a sputtering apparatus that performs film deposition using the sputtering method.

[0019] The film deposition apparatus 10 is an arc ion plating apparatus. The film deposition apparatus 10 comprises 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.

[0020] The vacuum chamber 12 houses a rotary table 14 and a plurality of substrate holders 16 arranged on the rotary table 14. The inside of the vacuum chamber 12 (i.e., the space housing the rotary table 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 deposition process. The vacuum chamber 12 is provided with a gas inlet 12A and an exhaust port 12B.

[0021] The rotary table 14 has a disc shape including a center line extending in the vertical direction in Figure 1. The rotary table 14 is located inside the vacuum chamber 12. During the film deposition process, the rotary table 14 rotates around its center line while supporting a plurality of substrate holders 16. The rotary table 14 may further include a rotating base on which each of the plurality of substrate holders 16 is individually positioned 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 the two shown in Figure 1.

[0022] Each of the multiple substrate holders 16 supports a workpiece W (substrate) on which a film is to be formed. In this embodiment, the workpiece W is arranged on the outer circumferential surface of the substrate holder 16. Note that only some of the workpiece W are shown in Figure 1.

[0023] In this embodiment, the workpiece W is made of A6061 alloy (Al alloy) (also called Al base material) and is a square plate measuring 20 mm x 20 mm. The thickness of the workpiece W is 5 mm. However, the material and shape of the workpiece W are not limited to this.

[0024] Each of the multiple base material holders 16 is formed of a conductive material. The conductive material is, for example, stainless steel.

[0025] Multiple substrate holders 16 are arranged at equal intervals in the circumferential direction of the rotary table 14. In this state, the center line of each of the multiple substrate holders 16 is parallel to the center line of the rotary table 14.

[0026] The bias power supply 18 applies a negative bias voltage to each of the multiple substrate holders 16 via the rotary table 14. In this embodiment, the bias power supply 18 intermittently applies a negative bias voltage to each of the multiple substrate holders 16. In other words, the bias power supply 18 is a pulse power supply. When the resistance of the film formed on the workpiece W is relatively high, applying a DC bias as the bias voltage can cause a problem of charge accumulation (charge up) due to incident ions. On the other hand, as in this embodiment, by applying a pulse voltage as the bias voltage, the above problem can be suppressed even when the resistance of the film formed on the workpiece W is relatively high. More specifically, by switching the bias between the negative side and 0V or the positive side as a pulse voltage on the order of μS or mS, the charge up problem can be suppressed.

[0027] Furthermore, when a negative bias voltage is not applied to the bias power supply 18 during the film deposition process, no bias is applied. Alternatively, the bias power supply 18 can alternately apply a negative bias voltage and a positive bias voltage to each of the multiple substrate holders 16. The absolute value of the negative bias voltage is greater than the absolute value of the positive bias voltage.

[0028] Furthermore, if negative and positive bias voltages are applied alternately, the bias power supply 18 may be, for example, an AC power supply or an RF power supply.

[0029] Target 20 is a disc-shaped component made of yttrium. For example, Target 20 is a disc with a diameter of 100 mm.

[0030] The arc power supply 22 is a DC power supply that functions as a discharge power source to generate a vacuum arc discharge in the target 20 placed in the vacuum chamber 12. In this case, the target 20 functions as the cathode in the discharge. On the other hand, as shown in Figure 1, the vacuum chamber 12 functions as the anode in the discharge. The target 20 receives the discharge generated by the arc power supply 22 and releases yttrium ions evaporated (molten) from its surface. The arc power supply 22, together with the target 20, constitutes an arc evaporation source.

[0031] The heater 24 is located inside the vacuum chamber 12 and generates heat by receiving current from a heater power supply (not shown). As a result, the environment inside the vacuum chamber 12 and the workpiece W are heated.

[0032] 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 other embodiments, the amount of gas supplied may be adjusted manually by an operator.

[0033] The vacuum pump P creates a vacuum in the internal space of the vacuum chamber 12 through the exhaust port 12B (vacuuming).

[0034] In addition to the regulators mentioned above, the controller 50 controls the vacuum pump P, the bias power supply 18 and arc power supply 22, the various voltages and current values ​​of the heater 24, and the rotation of the rotary table 14. [Examples]

[0035] Next, an example of the film deposition method according to this embodiment will be described. In the following description, oxygen may be denoted as O and yttrium as Y. Furthermore, the present invention is not limited to the scope of the following examples. In carrying out the film deposition method, as shown in Figure 1, the target 20 and workpiece W are installed in the film deposition apparatus 10, and the vacuum chamber 12 is evacuated to a vacuum state using a vacuum pump P.

[0036] Next, after preheating the vacuum chamber 12 with 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, bombardment is performed on the surface of the workpiece W using 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.

[0037] After the bombardment described above, an Ar-O2 mixed gas (e.g., 450 sccm of Ar and 50 sccm of oxygen) is introduced into the chamber so that the pressure inside the chamber is around 2 Pa. To maintain a stable discharge, it is desirable to set the total pressure inside the chamber within the range of 0.6 Pa to 4 Pa.

[0038] Next, a target 20 made of metallic yttrium is discharged in a vacuum chamber 12 while functioning as a cathode, and a yttrium oxide film is deposited on the workpiece W. At this time, the temperature of the workpiece W during film deposition is around 300°C (200°C to 400°C), the arc current is 100A (preferably in the range of 100A to 125A), and the voltage applied to the workpiece W is a unipolar pulse with a frequency of 200kHz and a duty cycle of 56%, with the average voltage varying between 10 and 100V. The thickness of the yttrium oxide film formed on the workpiece W is approximately 50 to 100 μm. As mentioned above, as an example, A6061Al (20 mm x 20 mm rectangular piece shape, 5 mm thick) is used as the workpiece W. In this experiment, the workpiece W (Al substrate) was placed at various distances of approximately 155 to 400 mm from the target 20.

[0039] In this embodiment, experiments were also conducted using a different AIP (Air Injection Precipitation) deposition apparatus than the one described above. In this case, an Ar-O2 gas mixture (Ar 900 sccm, oxygen flow rate approximately 50 sccm) was introduced into the chamber at a pressure of around 1 Pa, and a metal Y cathode was discharged to deposit a yttrium oxide film on the substrate. In this case, the substrate temperature during deposition was around 200°C, the arc current was 100A, and the voltage applied to the workpiece W was a unipolar pulse with a frequency of 30kHz and a duty cycle of 50%, with the average voltage varying between 40 and 60V.

[0040] Next, we will explain the evaluation method for the yttrium oxide film formed on the workpiece W, along with the indicators used.

[0041] (1) Evaluation of particle (foreign matter) shape A test specimen (workpiece W made of an Al substrate) with a film formed on it was cut along the film thickness direction, embedded in an evaluation resin, and its cross-section was observed from the cross-sectional direction using a Scanning Electron Microscope (SEM). Specifically, the film portion of the backscattered electron image at a magnification of 500x was image-processed, and the shape of particles within the film with a circumference of approximately 2.7 μm, i.e., a circular diameter of approximately 0.86 μm or more, was analyzed from the binarized image. These particles are considered foreign matter compared to the main component of the yttrium oxide film, and most of them are areas with a lower oxygen content compared to the yttrium oxide matrix. The area of ​​the SEM image analyzed is approximately 100 μm (film thickness) × 250 μm (width). In other words, the particles in the following explanation refer to particulate foreign matter made of a material different from yttrium oxide within the yttrium oxide film.

[0042] Figures 2A and 2B are magnified cross-sectional images showing particles in a yttrium oxide film. Whether the particles have a nearly circular shape as shown in Figure 2A, or a long elliptical shape as shown in Figure 2B, the major axis and minor axis can be identified through image analysis. The ellipse that best fits the particle shape is determined, its major axis and orthogonal minor axis are determined, and the flattening ratio is calculated. Here, the ratio of the major axis to the minor axis is defined as the flattening ratio for each particle. Note that particles that fly in a molten state become flattened along the substrate surface of the workpiece W, and therefore rarely extend diagonally relative to the substrate surface; however, the same method for calculating the flattening ratio is used even for particles that extend diagonally. Under each condition, the average value of the flattening ratios of multiple particles in the aforementioned SEM images is calculated. Here, the shape of a particle is defined by observation from a cross-sectional direction. If the particle is circular when observed from a cross-sectional direction, the actual particle shape will be spherical. If it is elliptical or flattened, the actual shape will be closer to an ellipsoid or a thick disk.

[0043] (2) Evaluation of porosity In a sample prepared in the same manner as in (1), the cross-section was observed using an SEM image at a magnification of 500x, and the voids in the film observable in the cross-section were calculated by image analysis. The procedure for image analysis is as follows: (Step 1) Cut out the analysis portion from the image. At this time, a region approximately 20 μm deep from the surface of the film is cut out. (Step 2) Binarize the image. (Step 3) Calculate the defect (void) area. The ratio of the area of ​​voids included in the image is evaluated as the void ratio. Note that voids are formed by nodules generated from particles. When the shape of the particles is spherical, it is presumed that surface tension acts in space after they are released in a molten state. If they solidify in that spherical shape and adhere to the workpiece W (substrate), a void is created between the spherical particle and the substrate at the bottom, and it is thought that this void is not filled by the film-forming particles incident from the vertical direction.

[0044] Figures 3A and 3B are cross-sectional images of the substrate and the yttrium oxide film. In both cross-sectional images, the lower side is the substrate and the upper side is the film. Figure 3A mainly shows particles with the shape shown in Figure 2A, and Figure 3B mainly shows particles with the shape shown in Figure 2B. Figure 4A shows the results of image analysis applied to the yttrium oxide film region of Figure 3A. Figure 4B shows the results of image analysis applied to the yttrium oxide film region of Figure 3B.

[0045] The images in Figures 3A and 4A show the results of experiments conducted under conditions where the shortest distance between the target and the substrate was 400 mm, while the images in Figures 3B and 4B show the results of experiments conducted under conditions where the shortest distance between the target and the substrate was 155 mm. Under the conditions in Figures 3A and 4A, the average flatness ratio of multiple particles in the images was 1.2, and the void ratio was 1.7%. On the other hand, under the conditions in Figures 3B and 4B, the average flatness ratio of multiple particles in the images was 3.7, and the void ratio was 0.15%. These results newly reveal that in coatings where the particle shape is close to flat and many particles have a large flatness ratio, the generation of nodules is suppressed and the voids are reduced. Note that the black areas visible around the white particles in Figure 3A are voids. In Figure 3B, these voids are not very visible.

[0046] Figure 5 is a graph showing the relationship between particle flatness and the porosity of the coating. As mentioned above, the graph shows the relationship between the particle flatness (average value) and porosity in the coating, which were obtained by image analysis from cross-sectional SEM observation. As shown in Figure 5, when the average value of particle flatness is small, i.e., when the shape of the particles is close to a sphere, the porosity shows a large value, whereas when the flatness exceeds 1.5 (see dashed line in Figure 5), the porosity becomes 0.2% or less, and it was found that a dense coating can be formed.

[0047] Figure 6 is a graph showing the relationship between the TS distance and the flattening ratio of particles. The TS distance is defined as the straight-line distance between the substrate and the target. Figure 6 shows the relationship between the shortest TS distance and the flattening ratio (average value) of particles contained in the film when the TS distance is varied in film deposition using the AIP method. The shortest distance is defined as the distance when the substrate and target are closest together, as shown in Figure 1 when the substrate is mounted on a rotary table. Strictly speaking, the TS distance changes during film deposition because the target is consumed by discharge, but here it is defined as the distance from the target surface at the start of film deposition. Even when the substrate moves along a trajectory other than rotation, the shortest distance is defined as the distance when the substrate and target are closest together. During the experiment, the surface of the target gradually wears down, so the distance gradually increases. When the TS distance from the target to the substrate is 300 mm or less, the flattening ratio of particles contained in the film is greater than 1.5. In this case, it was found that a dense yttrium oxide film with a small porosity can be formed, as shown in the graph in Figure 5.

[0048] Figure 7 is a graph showing the relationship between film thickness and porosity. Figure 7 shows the relationship between film thickness and porosity of a yttrium oxide film formed with a TS distance of 400 mm, as described above. The porosity was calculated for a thick yttrium oxide film of about 100 μm, by calculating the porosity in each region from the interface at 25, 50, and 75 μm, as well as in the overall film thickness, and using these values ​​as the values ​​for each film thickness. As a result, although there is some variation, it was found that the porosity exceeds 0.2% when the film thickness exceeds 30 μm. On the other hand, as shown in Figures 3B and 4B, when the TS distance is short, the particle flattening ratio becomes a value greater than 2, and the porosity is 0.2% or less. From this, it was confirmed that the present invention is effective for film thicknesses of 30 μm or more.

[0049] In this embodiment, in the yttrium oxide film formed on the workpiece W, the average ratio of the major axis to the minor axis (flatness) when each of the multiple particles mainly composed of metallic yttrium present in the film, in a cross-section including the thickness direction of the film, is approximated by an ellipse, is greater than 1.5. Furthermore, it is more desirable that the average flatness be greater than 2.0. Moreover, it is even more desirable that the average flatness be 3.0 or higher.

[0050] This configuration prevents abnormal growth (nodule growth) from occurring in the coating, which originates from particles and forms voids. As a result, it is possible to prevent a decrease in plasma resistance.

[0051] In the above configuration, the coating may have a thickness of 30 μm or more.

[0052] Nodule growth and void formation by particles become significant when the film thickness increases to 30 μm or more, and even 40 μm or more. With this configuration, by focusing on the flattening ratio of the particles, it is possible to suppress abnormal growth and void formation that occur in the film starting from foreign matter, even within this thickness range, and thereby prevent a decrease in plasma resistance.

[0053] The present invention provides a method for forming the yttrium oxide film described above, comprising appropriately setting the distance between the target and the substrate, and then melting and evaporating the surface of the target by an arc ion plating method to form the film on the substrate. The appropriate distance in the above is a predetermined distance such that the shape of the particles in cross-section has a flattened shape with a major axis / minor axis ratio of 1.5 or more.

[0054] Particle contamination is particularly pronounced in the AIP method, where melting and scattering of the target due to arc discharge are unavoidable. According to this method, even in such cases, abnormal growth and void formation caused by foreign particles within the coating are suppressed, thereby preventing a decrease in plasma resistance. Specifically, by appropriately setting the distance between the target 20 and the workpiece W (TS distance), this method allows for the particle shape to be flattened with a major axis / minor axis ratio exceeding 1.5. In the AIP method, particles (molten metal) scattered from the target 20 experience a temperature decrease due to radiation during their journey from the target 20 to the workpiece W. If the distance from the target 20 to the workpiece W is long, the particles cool and solidify before reaching the workpiece W, becoming spherical and adhering to the workpiece W. In this case, a void is created between the workpiece W (substrate) and the particles, and nodules are formed starting from this point. On the other hand, if the distance from the target 20 to the workpiece W is short, the particles are more likely to reach the workpiece W in a molten state, deform along the shape of the workpiece W, and become flattened. In this case, since voids like those in the spherical particles described above are less likely to form, nodule growth is less likely to occur.

[0055] The above method may further include setting the distance between the target and the substrate during film formation so that the porosity of the film is 0.2% or less.

[0056] According to this method, a dense yttrium oxide film can be formed by setting the porosity of the film to 0.2% or less.

[0057] The above method may further include setting the shortest distance between the target and the substrate during film formation to 300 mm or less. More preferably, the shortest distance is 200 mm or less.

[0058] As described above, this embodiment provides a yttrium oxide coating and a method for forming the coating, in which a decrease in plasma resistance due to abnormal growth originating from foreign matter is suppressed.

[0059] To give a more specific example of the film formation method according to this embodiment, the method is a method for forming a yttrium oxide film on a substrate to be formed by arc ion plating. The method comprises 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 oxygen to form a yttrium oxide film on the substrate. The film formed by such a film formation method has the flattening characteristics described above.

[0060] Furthermore, in order to obtain a practical film deposition rate, it is desirable to deposit the film using the arc ion plating method rather than the known ion plating method or reactive sputtering method. For example, known etching equipment generally uses films with a thickness of 100 μm or more, and the slow deposition rate is a problem with ion plating or sputtering methods. On the other hand, the inventors have discovered that a significant problem with the arc ion plating method, which is expected to have a fast deposition rate, is that abnormal growth (nodule growth) occurs starting from particles (foreign matter), and when the porosity increases, the plasma resistance decreases. The inventors have newly discovered that this problem can be solved by controlling the flattening ratio of particles in the film. In the thickness range described above, it is difficult to achieve a practical film deposition rate while keeping the porosity low with known sputtering methods.

[0061] Furthermore, the yttrium oxide film in this invention is a state in which Y2O3 and Y are mixed within the film, and as a result of a change in the ratio of Y2O3 to Y, the ratio of Y to O within the film changes. In this invention, films in such a mixed state of Y2O3 and Y are collectively referred to as "yttrium oxide films." In this case, the ratio of Y to O is an atomic ratio.

[0062] The embodiments of the present invention have been described in detail above. Since the yttrium oxide film obtained by the film formation method according to the present invention has excellent plasma resistance, it can be widely applied to components exposed to plasma, such as those found in semiconductor manufacturing equipment.

[0063] These are merely illustrative examples, and the present invention is not to be interpreted in any way as being limited by the above-described embodiments. In the present invention, the substrate is not limited to an insulating material, but may also be a conductive material. The method of forming the film is not limited to the AIP method, but may also be other PVD methods. In this case as well, nodule growth can occur, and the present invention can be effectively utilized. However, the present invention is particularly effective in the AIP method, which tends to generate a large number of particles. [Explanation of Symbols]

[0064] 10 Film deposition equipment 12 Vacuum Chamber 14 Rotating Table 16. Base material holder 18 Bias power supply 20 Targets 22 Arc power supply 24 Heater 30 argon tanks 32 oxygen tanks 50 controllers W Work W (Base Material)

Claims

1. A yttrium oxide film formed on a substrate, A yttrium oxide film in which, in a cross-section including the thickness direction of the film, the average ratio of the major axis to the minor axis when each of the multiple particles, mainly composed of metallic yttrium, present in the film is approximated by an ellipse is greater than 1.

5.

2. The yttrium oxide film according to claim 1, The aforementioned film is a yttrium oxide film having a thickness of 30 μm or more.

3. A method for forming a yttrium oxide film according to claim 1, A film formation method comprising appropriately setting the distance between the target and the substrate, and then melting and evaporating the surface of the target by an arc ion plating method to form the film on the substrate.

4. A film formation method according to claim 3, A film formation method further comprising setting the distance between the target and the substrate during film formation so that the porosity of the film is 0.2% or less.

5. A film formation method according to claim 4, A film deposition method further comprising setting the shortest distance between the target and the substrate during film deposition to 300 mm or less.

Images