Ion milling source, vacuum processing apparatus, and vacuum processing method

Abstract

To provide an ion milling source, a vacuum processor, and a method for vacuum processing which have an excellent resistance to fluorine as well when using fluorine-based gas as a processing gas.SOLUTION: The ion milling source includes a vacuum container, a discharge electrode, and an extraction electrode. The discharge electrode ionizes the fluorine-containing gas supplied into the vacuum container, in the vacuum container. The extraction electrode has a plurality of through-holes and contains a fluorine-resistive material, and extracts ion particles in the fluorine-containing gas ionized in the vacuum container to the outside of the vacuum container through the through-holes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ion milling source, a vacuum processing apparatus, and a vacuum processing method. [Background technology]

[0002] Electronic devices such as smartphones are equipped with filter elements that transmit and receive signals in specific frequency bands within the radio frequency range. These filter elements are formed on substrates using wafer processes. The substrates on which these filter elements are mounted must be flattened to the order of several nanometers.

[0003] One technique for planarizing a substrate involves accelerating ions using an electric field in a reduced pressure atmosphere and irradiating the substrate with the accelerated ions to flatten it. An example of an apparatus for irradiating ions is an ion milling apparatus (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-156077 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned ion milling apparatus, the kinetic energy of ions is lower than that of an ion implantation apparatus. Therefore, it is difficult to process a target object such as a substrate with argon ions, so a highly reactive fluorine-based gas may be used. However, when a fluorine-based gas is used, depending on the material of the extraction electrode (e.g., graphite), there is a risk that the extraction electrode may be corroded by the fluorine-based gas.

[0006] In view of the above circumstances, an object of the present invention is to provide an ion milling source, a vacuum processing apparatus, and a vacuum processing method that are excellent in fluorine resistance even when a fluorine-based gas is used as the processing gas. [Means for solving the problem]

[0007] In order to achieve the above object, an ion milling source according to one aspect of the present invention includes a vacuum vessel, a discharge electrode, and an extraction electrode. The discharge electrode ionizes the fluorine-containing gas supplied to the vacuum vessel within the vacuum vessel. The extraction electrode has a plurality of through holes, contains a fluorine-resistant material, and extracts ion particles in the fluorine-containing gas ionized within the vacuum vessel to the outside of the vacuum vessel through the plurality of through holes.

[0008] Such an ion milling source exhibits excellent fluorine resistance even when a fluorine-based gas is used as the processing gas.

[0009] In the ion milling source, the extraction electrode may be configured by overlapping a plurality of electrodes, and at least one of the plurality of electrodes may be configured from the fluorine-resistant material.

[0010] Such an ion milling source exhibits excellent fluorine resistance even when a fluorine-based gas is used as the processing gas.

[0011] In the ion milling source, the fluorine-resistant material may include at least one of aluminum-containing graphite and silicon-doped aluminum-containing graphite.

[0012] Such an ion milling source exhibits excellent fluorine resistance even when a fluorine-based gas is used as the processing gas.

[0013] In the ion milling source, the fluorine-resistant material may include at least one of aluminum, cobalt, nickel, copper, and a nickel-chromium-iron alloy.

[0014] Such an ion milling source exhibits excellent fluorine resistance even when a fluorine-based gas is used as the processing gas.

[0015] In order to achieve the above object, a vacuum processing apparatus according to one aspect of the present invention includes a vacuum chamber, an ion milling source attached to the vacuum chamber, a gas supply device for supplying the fluorine-containing gas to the vacuum vessel; a support table that is provided in the vacuum chamber and positioned opposite the ion milling source and that supports a substrate; and an exhaust device for exhausting the inside of the vacuum chamber.

[0016] Such a vacuum processing apparatus exhibits excellent fluorine resistance even when a fluorine-based gas is used as the processing gas.

[0017] In the vacuum processing apparatus, the extraction electrode may be formed by overlapping a plurality of electrodes, and at least one of the plurality of electrodes may be made of the fluorine-resistant material.

[0018] Such a vacuum processing apparatus exhibits excellent fluorine resistance even when a fluorine-based gas is used as the processing gas.

[0019] In the vacuum processing apparatus, the fluorine-resistant material may include at least one of aluminum-containing graphite and silicon-added aluminum-containing graphite.

[0020] Such a vacuum processing apparatus exhibits excellent fluorine resistance even when a fluorine-based gas is used as the processing gas.

[0021] In the vacuum processing apparatus, the fluorine-resistant material may include at least one of aluminum, cobalt, nickel, copper, and a nickel-chromium-iron alloy.

[0022] Such a vacuum processing apparatus exhibits excellent fluorine resistance even when a fluorine-based gas is used as the processing gas.

[0023] In order to achieve the above object, a vacuum processing method according to one aspect of the present invention includes: a substrate is placed opposite an ion milling source in a reduced pressure atmosphere, the ion milling source having a vacuum vessel, a discharge electrode that ionizes a fluorine-containing gas supplied to the vacuum vessel within the vacuum vessel, and an extraction electrode that has a plurality of through holes, includes a fluorine-resistant material, and extracts ion particles in the fluorine-containing gas ionized within the vacuum vessel into the vacuum tank via the plurality of through holes; The fluorine-containing gas is supplied to the vacuum vessel, and the ionized fluorine-containing gas is ejected from the ion milling source; The substrate is exposed to the ionized fluorine-containing gas.

[0024] Such a vacuum processing method allows stable processing of substrates due to the excellent fluorine resistance even when a fluorine-based gas is used as the processing gas.

[0025] In the vacuum processing method, the fluorine-resistant material may be at least one of aluminum-containing graphite and aluminum-containing graphite doped with silicon.

[0026] Such a vacuum processing method allows stable processing of substrates due to the excellent fluorine resistance even when a fluorine-based gas is used as the processing gas.

[0027] In the vacuum processing method, the fluorine-resistant material may be at least one of aluminum, cobalt, nickel, copper, and a nickel-chromium-iron alloy.

[0028] Such a vacuum processing method allows stable processing of substrates due to the excellent fluorine resistance even when a fluorine-based gas is used as the processing gas.

[0029] In the vacuum processing method, the ionized fluorine-containing gas may be accelerated with a voltage of 0.5 KeV to 5 KeV and irradiated onto the substrate.

[0030] Such a vacuum processing method allows stable processing of substrates due to the excellent fluorine resistance even when a fluorine-based gas is used as the processing gas. [Effects of the Invention]

[0031] As described above, the present invention provides an ion milling source, a vacuum processing apparatus, and a vacuum processing method that are excellent in fluorine resistance even when ions of a fluorine-based gas are used. [Brief explanation of the drawings]

[0032] [Figure 1] 1A is a schematic cross-sectional view showing an ion milling source according to the present embodiment, and FIG. 1B is a schematic plan view showing an extraction electrode according to the present embodiment. [Figure 2] 1 is a schematic diagram showing a vacuum processing apparatus according to an embodiment of the present invention; [Figure 3] 10 is a graph showing a comparison of corrosion in the through-holes of the extraction electrode. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The configurations shown in each drawing are examples. XYZ axis coordinates may be introduced in each drawing. Furthermore, the same reference numerals may be used to refer to identical components or components having the same functions, and after describing the components, further description may be omitted as appropriate. Furthermore, the numerical values ​​shown below are examples and are not limited to these examples.

[0034] Fig. 1(a) is a schematic cross-sectional view showing an ion milling source according to this embodiment, and Fig. 1(b) is a schematic plan view showing an extraction electrode according to this embodiment.

[0035] As shown in FIG. 1( a ), the ion milling source 1 includes a vacuum vessel 10 , a discharge electrode 20 , an extraction electrode 30 , a lid 11 , a shielding plate 12 , and a gas supply port 40 .

[0036] The vacuum vessel 10 is a cylindrical vessel that can maintain a reduced pressure state using an exhaust device (described later). The vacuum vessel 10 also defines plasma. The vacuum vessel 10 is made of a material that is permeable to the electric field emitted from the discharge electrode 20. For example, the material of the vacuum vessel 10 is quartz, alumina, or the like. The inner wall of the vacuum vessel 10 may be provided with a coating that is permeable to the electric field emitted by the discharge electrode 20 and has excellent fluorine resistance. For example, the coating is made of at least one of yttria, silicon nitride, and silicon carbide.

[0037] When a discharge gas (e.g., a fluorine-containing gas) is supplied to the vacuum vessel 10, the discharge electrode 20 causes the discharge gas to discharge inside the vacuum vessel 10. The discharge electrode 20 is a coil-shaped electrode (antenna) that winds around the vacuum vessel 10. The number of turns of the discharge electrode 20 is not limited to the number shown in the figure. Furthermore, a coil-shaped discharge electrode may be wound around the outside of the discharge electrode 20 shown in the figure.

[0038] The discharge electrode 20 is connected to a high-frequency power supply 50. High-frequency power is supplied to the discharge electrode 20 from the high-frequency power supply 50. A matching circuit (not shown) is provided between the discharge electrode 20 and the high-frequency power supply 50. The high-frequency power supply 50 is, for example, an RF power supply. The high-frequency power supply 50 may also be a VHF power supply. A permanent magnet may also be placed between the discharge electrode 20 and the vacuum vessel 10. When a discharge gas is introduced into the vacuum vessel 10 and high-frequency power is supplied to the discharge electrode 20 from the high-frequency power supply 50, plasma is generated inside the vacuum vessel 10 by inductively coupled discharge. The plasma generation means is not limited to the inductive coupling method, and may also be an electron cyclotron resonance plasma source, a helicon wave plasma source, or the like.

[0039] The extraction electrode 30 includes a first electrode 31, a second electrode 32, and a third electrode 33. The extraction electrode 30 is configured by overlapping a plurality of electrodes (the first electrode 31, the second electrode 32, and the third electrode 33) in one axial direction (the X-axis direction) extending from a gas supply port 40 of a pipe or the like toward the lid 11 or the shielding plate 12 (hereinafter, referred to as the lid 11, etc.). The first electrode 31, the second electrode 32, and the third electrode 33 are arranged side by side in the axial direction. The first electrode 31, the second electrode 32, and the third electrode 33 are, for example, plate-shaped electrodes. The planar shapes of the first electrode 31, the second electrode 32, and the third electrode 33 are, for example, disk-shaped.

[0040] The thickness of the first electrode 31 is thinner than the second electrode 32 and the third electrode 33. For example, the thickness of the first electrode 31 is set to 0.5 mm to 10 mm, e.g., 0.5 mm, the thickness of the second electrode 32 is set to 0.5 mm to 10 mm, e.g., 1.5 mm, and the thickness of the third electrode 33 is set to 0.5 mm to 10 mm, e.g., 1.5 mm. The distance between the first electrode 31 and the second electrode 32 is set to 0.1 mm to 5 mm, and the distance between the second electrode 32 and the third electrode 33 is set to 0.1 mm to 10 mm.

[0041] The first electrode 31 has a main surface 311 on the gas supply port 40 side and a main surface 312 on the lid portion 11 side etc. The second electrode 32 has a main surface 321 on the gas supply port 40 side and a main surface 322 on the lid portion 11 side etc. The third electrode 33 has a main surface 331 on the gas supply port 40 side and a main surface 332 on the lid portion 11 side etc. The main surface 312 of the first electrode 31 and the main surface 321 of the second electrode 32 face each other in one axial direction. The main surface 322 of the second electrode 32 and the main surface 331 of the third electrode 33 face each other in one axial direction.

[0042] For example, when a fluorine-containing gas is used as the discharge gas, the extraction electrode 30 extracts ion particles in the fluorine-containing gas ionized inside the vacuum vessel 10 to the outside of the vacuum vessel 10 through the multiple through-holes. Examples of fluorine-containing gases include SF6, CF4, NF3, and CHF3, with SF6 being preferred. Each fluorine-containing gas may be diluted with a gas such as Ar.

[0043] Here, a material with a low sputtering rate, excellent oxidation resistance, and excellent conductivity may be typically selected as the material for the extraction electrode 30. Graphite is an example of such a material. However, graphite has low resistance to fluorine, and when a fluorine-based gas is used as the discharge gas, there is a risk that the extraction electrode will corrode due to a chemical reaction between the graphite and fluorine.

[0044] Therefore, the material for the extraction electrode 30 to be used instead of graphite must be fluorine-resistant and have electrical conductivity (1×10 6 S / m) and has a linear expansion coefficient similar to that of graphite (2×10 -6 / K~4×10 -6 / K).

[0045] The extraction electrode 30 according to this embodiment is made of a material that includes a fluorine-resistant material and satisfies the above-mentioned conditions for electrical conductivity and thermal expansion characteristics. For example, at least one of the first electrode 31, the second electrode 32, and the third electrode 33 is made of the fluorine-resistant material shown below. The fluorine-resistant material includes a first fluorine-resistant material or a second fluorine-resistant material.

[0046] The first fluorine-resistant material may be at least one of aluminum-containing graphite and aluminum-containing graphite doped with silicon. The second fluorine-resistant material may be at least one of aluminum, cobalt, nickel, copper, and a nickel-chromium-iron alloy. By using such a fluorine-resistant material for at least one of the first electrode 31, the second electrode 32, and the third electrode 33, the inner diameters of the through-holes provided in the first electrode 31, the second electrode 32, and the third electrode 33 are less likely to change due to corrosion. As a result, the divergence angle of the ion beam is less likely to change, and the divergence angle of the ion beam is stabilized.

[0047] Here, aluminum-containing graphite is graphite impregnated with 10 wt% to 30 wt% aluminum. If the aluminum content of the graphite is less than 10 wt%, the aluminum-containing graphite is corroded by fluorine-based gas, which is undesirable. On the other hand, if the aluminum content of the graphite is more than 30 wt%, the aluminum is not uniformly dispersed in the graphite, and the linear expansion coefficient increases, which reduces processing accuracy, which is undesirable.

[0048] Furthermore, silicon in an amount of 1 wt% to 20 wt% may be added to aluminum-containing graphite (Al: 10 wt% to 30 wt%).

[0049] Furthermore, since the second fluorine-resistant material has a larger coefficient of linear thermal expansion than the first fluorine-resistant material, it is more desirable to use the first fluorine-resistant material.

[0050] An insulator 101 is provided between the vacuum vessel 10 and the first electrode 31, an insulator 102 is provided between the first electrode 31 and the second electrode 32, and an insulator 103 is provided between the second electrode 32 and the third electrode 33. A DC power supply 51 is connected to the first electrode 31, and a predetermined potential is supplied to the first electrode 31. For example, a positive potential is applied to the first electrode 31. A DC power supply 52 is connected to the second electrode 32, and a predetermined potential is supplied to the second electrode 32. For example, a negative potential is applied to the second electrode 32. The third electrode 33 is set to a ground potential. Note that, if necessary, a negative potential may be applied to the first electrode 31, and a positive potential may be applied to the second electrode 32. Furthermore, a DC power supply may be connected to the third electrode 33, and a positive or negative potential may be applied to the third electrode 33. That is, the first electrode 31, the second electrode 32, and the third electrode 33 can be supplied with a potential independently.

[0051] The first electrode 31 has a plurality of through-holes 31h through which ions in the plasma pass. The second electrode 32 has a plurality of through-holes 32h through which ions in the plasma pass. The third electrode 33 has a plurality of through-holes 33h through which ions in the plasma pass.

[0052] For example, FIG. 1(b) shows a plan view of the first electrode 31 as a representative of the first electrode 31, the second electrode 32, and the third electrode 33. A plurality of through-holes 31h are provided in the center of the first electrode 31, penetrating between the main surface 311 and the main surface 312. The plurality of through-holes 31h may be arranged in a honeycomb pattern as shown in the figure, or in a lattice pattern. Such a plurality of through-holes is also provided in the second electrode 32 and the third electrode 33. Here, the regions in which the plurality of through-holes are arranged in each of the first electrode 31, the second electrode 32, and the third electrode 33 are referred to as regions 34.

[0053] For example, when the first electrode 31, the second electrode 32, and the third electrode 33 are arranged one on top of the other in the axial direction, and when any one of the through-holes 31h is viewed from the gas supply port 40 side, any one of the through-holes 32h is located beyond this through-hole 31h, and any one of the through-holes 33h is located beyond that. That is, ions that have passed through any one of the through-holes 31h in the first electrode 31 are not blocked by the second electrode 32 and the third electrode 33, and pass through the through-hole 32h and the through-hole 33h located beyond that in that order.

[0054] The inner diameters of through holes 32h and 33h are set to be larger than the inner diameter of through hole 31h. For example, the inner diameter of through hole 31h is set to approximately 1.5 mm, and the inner diameter of through hole 32h is set to approximately 2 mm. As a result, ions that have passed through through hole 31h are less likely to be blocked by second electrode 32 and third electrode 33, and after passing through through hole 32h, they pass through through hole 33h.

[0055] In particular, when the first electrode 31, the second electrode 32, and the third electrode 33 are made of at least one of aluminum-containing graphite and aluminum-containing graphite doped with silicon, the linear expansion coefficients of the first electrode 31, the second electrode 32, and the third electrode 33 become close to that of graphite. As a result, even if the temperatures of the first electrode 31, the second electrode 32, and the third electrode 33 rise during processing, misalignment between adjacent through holes in a direction perpendicular to the axial direction is unlikely to occur between the through holes. In particular, because the first electrode 31 is closer to the plasma than the second electrode 32 and the third electrode 33, misalignment between the through holes in a direction perpendicular to the axial direction is suppressed even if the temperature of the first electrode 31 rises more than the temperatures of the second electrode 32 and the third electrode 33.

[0056] The inner diameter of the through-hole 33h may be set smaller than the inner diameter of the through-hole 32h, thereby suppressing the backflow of electrons that pass through the third electrode 33 from the substrate 81 side and fly to the second electrode 32. Alternatively, the re-adhesion of the coating that peels off from the substrate 81 side to the first electrode 31 or the second electrode 32 is suppressed.

[0057] The lid portion 11 is disposed so as to overlap the extraction electrode 30 in one axial direction. For example, the lid portion 11 is disposed next to the extraction electrode 30 on the opposite side from the gas supply port 40. The lid portion 11 has a planar shape, for example, a disk shape. An insulator 104 is provided between the lid portion 11 and the third electrode 33 of the extraction electrode 30. An opening 11h is provided in the center of the lid portion 11, penetrating the lid portion 11 and allowing ions to pass through. The area of ​​the opening 11h is larger than the area of ​​the region 34. As a result, ions that have passed through the region 34 pass through the opening 11h without being blocked by the lid portion 11. The lid portion 11 may be made of the second fluorine-resistant material or the first fluorine-resistant material.

[0058] The shielding plate 12 is disposed so as to overlap the lid portion 11 in one axial direction. For example, the shielding plate 12 is disposed next to the lid portion 11 on the side opposite to the gas supply port 40. The planar shape of the shielding plate 12 is, for example, a disk shape. An insulator 105 is provided between the shielding plate 12 and the lid portion 11. An opening 12h is provided in the center of the shielding plate 12, through which ions pass through the shielding plate 12. The area of ​​the opening 12h is larger than the area of ​​the opening 11h. As a result, ions that pass through the opening 11h pass through the opening 12h without being blocked by the shielding plate 12. The shielding plate 12 may be made of the second fluorine-resistant material or the first fluorine-resistant material.

[0059] A DC power supply 55 is connected to the shielding plate 12. For example, when the ions released from the opening 11h of the lid portion 11 are positive ions, the potential of the shielding plate 12 is set to a predetermined negative potential in order to block these positive ions with the shielding plate 12. As a result, the positive ions are attracted to the shielding plate 12, and are blocked by the shielding plate 12.

[0060] FIG. 2 is a schematic diagram showing the vacuum processing apparatus of this embodiment.

[0061] The vacuum processing apparatus 2 is, for example, an ion milling apparatus, and includes an ion milling source 1, a high-frequency power supply 50, DC power supplies 51 and 52, a vacuum chamber 60, a gas supply device 70, a support stand 80, an exhaust device 90, and a control device 91. The vacuum chamber 60 is a container that can maintain a reduced pressure state using the exhaust device 90. The vacuum chamber 60 is set to ground potential. The capacity of the vacuum chamber 60 is larger than the capacity of the vacuum container 10. The ion milling source 1 is attached to the vacuum chamber 60. Ions emitted from the ion milling source 1 reach the substrate 81.

[0062] The gas supply device 70 supplies a discharge gas, such as a fluorine-containing gas, to the vacuum chamber 10 via the gas supply port 40. The gas supply device 70 includes a flow rate regulator that adjusts the flow rate of the discharge gas. The support table 80 is provided inside the vacuum chamber 60. The support table 80 is positioned opposite the ion milling source 1. The support table 80 supports a substrate 81. The support table 80 may be set to a predetermined temperature by a temperature regulator (not shown) provided outside the vacuum chamber 60. In addition, a bias power supply that can adjust the ion acceleration voltage may be connected to the support table 80.

[0063] The exhaust device 90 is a turbomolecular pump or the like, and exhausts the inside of the vacuum vessel 10 and the inside of the vacuum chamber 60. The substrate 81 is, for example, a metal nitride substrate, a substrate with a metal nitride film formed on its uppermost layer, or a substrate with a high-melting-point metal film formed on its uppermost layer. The substrate 81 is, for example, an aluminum nitride substrate, a substrate with an LT (LiTaO3) film, or a substrate with an aluminum nitride film, molybdenum film, or the like formed on its uppermost layer. Furthermore, the substrate 81 is not limited to the above examples, and may be a semiconductor substrate, or a semiconductor substrate with a silicon oxide film formed on its uppermost layer.

[0064] The ion milling source 1, high-frequency power supply 50, DC power supplies 51 and 52, gas supply device 70, support table 80, and exhaust device 90 are controlled by a control device 91. In the ion milling source 1, the ion acceleration voltage is set to, for example, greater than 0 KeV, for example, in the range of 0.5 KeV to 5 KeV. The discharge gas used may be at least one of SF, CF, CF / O, CHF, NF, etc. The discharge gas may be diluted with gases such as Ar, He, N, and O.

[0065] In this embodiment, such a vacuum processing apparatus 2 is used to perform vacuum processing on a substrate 81. For example, the substrate 81 is placed opposite the ion milling source 1 in a reduced pressure atmosphere. Next, a fluorine-containing gas is supplied to the vacuum vessel 10. Next, the ionized fluorine-containing gas is ejected from the ion milling source 1 into the vacuum chamber 60. Then, the ionized fluorine-containing gas is irradiated onto the substrate 81. An example of ion milling conditions is shown below.

[0066] (Ion milling conditions) Discharge gas: SF6 Discharge gas flow rate: 1sccm to 10sccm Discharge power: 50W~300W Vacuum chamber pressure: 1.0 x 10 -3 Pa~5×10 -2 Pa First electrode potential: +0.5kV~+5kV Second electrode potential: -0.1kV~-2kV Third electrode potential: ground potential Ion acceleration energy: 0.5KeV to 5KeV Substrate temperature: Room temperature Substrate: AlN wafer

[0067] Under the above ion milling conditions, the inside of the vacuum vessel 10 is filled with, for example, SF5 + A plasma containing ions is generated. These fluorine-containing positive ions (hereinafter, sometimes simply referred to as positive ions) pass through the through-holes 31h of the first electrode 31 and are accelerated by the electric field formed by the first electrode 31 and the second electrode 32. The acceleration energy of the ions is set to 0.5 KeV to 5 KeV. The positive ions then pass through the through-holes 32h of the second electrode 32 and then through the through-holes 33h of the third electrode 33, reaching the substrate 81. Under ion milling conditions, the potential of the third electrode 33 is set slightly higher (toward a positive potential) than the potential of the second electrode 32. This makes it possible to block electrons flowing back from the direction in which the ion beam is emitted.

[0068] The positive ions that reach the surface of the substrate 81 are highly reactive because they contain fluorine, and since positive ions continuously reach the surface of the substrate 81, the reaction of the positive ions is promoted by an ion-assisted reaction on the surface of the substrate 81. As a result, AlN decomposes on the surface of the substrate 81, and the surface of the substrate 81 is gradually eroded. For example, the vacuum processing of this embodiment can be applied to planarizing the surface of a substrate.

[0069] For example, Ar +It has been found that reactive etching using fluorine-containing positive ions results in a smoother surface of the substrate 81 after processing than physical etching using ions. For example, when an AlN substrate with an arithmetic mean roughness Ra of 2.7 nm before ion trimming is used, the surface roughness becomes smoother when Ar + It has been found that ion milling using ions results in an arithmetic mean roughness Ra of 1.2 nm, whereas ion milling using fluorine-containing positive ions results in an arithmetic mean roughness Ra of 0.6 nm. As such, it has been found that the vacuum processing of this embodiment makes it possible to achieve planarization on the order of 1 nm or less. The arithmetic mean roughness Ra was measured using an atomic force microscope (AFM).

[0070] However, during ion milling using fluorine-containing positive ions, the extraction electrode 30 must not be corroded by the fluorine-containing positive ions. In particular, since the second electrode 32 in the extraction electrode 30 is irradiated with fluorine-containing positive ions accelerated at a predetermined energy, it is desirable to suppress corrosion (reaction) at the second electrode 32. If the extraction electrode 30 is corroded by the fluorine-containing positive ions (the inner diameter of the through-hole increases), the divergence angle of the ion beam changes, making it difficult to ensure the reproducibility of the ion beam. In addition, there is a possibility of abnormal discharge occurring between the electrodes.

[0071] 3 is a graph showing a comparison of corrosion in the through-holes of the extraction electrodes. The horizontal axis represents the ion trimming time (h). The vertical axis represents the inner diameter (μm) of the through-hole 32h provided in the second electrode 32.

[0072] In the comparative example, the first electrode 31, the second electrode 32, and the third electrode 33 are made of graphite. In contrast, in this embodiment, the first electrode 31, the second electrode 32, and the third electrode 33 are made of, for example, graphite containing 15 wt% aluminum. As described above, the second electrode 32 in the extraction electrode 30 is irradiated with fluorine-containing positive ions accelerated at a predetermined energy, so it is desirable to suppress corrosion (reaction) in the second electrode 32. Figure 3 shows a comparison of the degree of corrosion. Figure 3 shows how much the inner diameter of the through-hole 32h in the second electrode 32 increases before and after ion milling when ion milling is performed for 500 hours. In other words, the larger the inner diameter, the more corroded the through-hole 32h is.

[0073] As shown in FIG. 3, in the comparative example, the inner diameter (diameter) before ion milling is 2017 μm, and after ion milling, the inner diameter increases to 2176 μm. In the comparative example, the difference is Δ159 μm. In contrast, in this embodiment, the inner diameter before ion milling is 2021 μm, and after ion milling, the inner diameter is reduced to 2029 μm. In this embodiment, the difference is Δ8 μm.

[0074] As described above, according to this embodiment, the surface of a metal nitride can be planarized to 1 nm or less by ion milling using a fluorine-containing gas as the source gas. Furthermore, it has been found that by using an extraction electrode 30 made of a fluorine-resistant material, contamination of the extraction electrode 30 by fluorine can be suppressed even when ion milling is performed using a fluorine-containing gas as the source gas.

[0075] Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the above-described embodiments and can be modified in various ways. For example, the ion milling source 1 is not limited to ion milling processes, but may also be applied to cleaning processes for the inner walls and internal components of a vacuum chamber 60. Furthermore, this embodiment is not limited to planarizing the substrate surface, but can also be applied to patterning processes for etching the underlying layer exposed from a mask pattern. Each embodiment is not necessarily independent, and can be combined as far as technically possible. [Explanation of symbols]

[0076] 1...Ion milling source 2...Vacuum processing equipment 10...Vacuum container 11...Lid part 11h…Aperture 12...Shielding plate 12h…Opening 20…discharge electrode 30…Extraction electrode 31...1st electrode 31h...Through hole 32…Second electrode 32h…Through hole 33...Third electrode 33h…Through hole 34…area 40...Gas supply port 50…High frequency power supply 51…DC power supply 52…DC power supply 55…DC power supply 60...Vacuum chamber 70...Gas supply device 80...Support stand 81... Circuit board 90...Exhaust system 91...Control device 101, 102, 103, 104, 105...Insulators 311, 312, 321, 322, 331, 332...Main surfaces

Claims

1. A vacuum vessel; a discharge electrode for ionizing a fluorine-containing gas supplied to the vacuum vessel within the vacuum vessel; an extraction electrode having a plurality of through holes, including a fluorine-resistant material, and extracting ion particles in the fluorine-containing gas ionized in the vacuum chamber to the outside of the vacuum chamber via the plurality of through holes; Equipped with The fluorine-resistant material includes at least one of aluminum-containing graphite and silicon-added aluminum-containing graphite. Ion milling source.

2. 10. The ion milling source of claim 1, the extraction electrode is configured by overlapping a plurality of electrodes, At least one of the plurality of electrodes is made of the fluorine-resistant material. Ion milling source.

3. A vacuum chamber; attached to the vacuum chamber, A vacuum vessel; a discharge electrode for ionizing a fluorine-containing gas supplied to the vacuum vessel within the vacuum vessel; an extraction electrode having a plurality of through holes, including a fluorine-resistant material, and extracting ion particles in the fluorine-containing gas ionized in the vacuum vessel into the vacuum chamber via the plurality of through holes; an ion milling source having a gas supply device for supplying the fluorine-containing gas to the vacuum vessel; a support table that is provided in the vacuum chamber and that is disposed opposite the ion milling source and that supports a substrate; an exhaust device that exhausts the inside of the vacuum chamber; Equipped with The fluorine-resistant material includes at least one of aluminum-containing graphite and silicon-added aluminum-containing graphite. Vacuum processing equipment.

4. 4. The vacuum processing apparatus according to claim 3, the extraction electrode is configured by overlapping a plurality of electrodes, At least one of the plurality of electrodes is made of the fluorine-resistant material. Vacuum processing equipment.

5. a substrate is placed facing an ion milling source in a reduced pressure atmosphere, the ion milling source including: a vacuum vessel attached to a vacuum chamber; a discharge electrode that ionizes a fluorine-containing gas supplied to the vacuum vessel within the vacuum vessel; and an extraction electrode that has a plurality of through holes, includes a fluorine-resistant material, and extracts ion particles in the fluorine-containing gas ionized within the vacuum vessel into the vacuum chamber via the plurality of through holes; supplying the fluorine-containing gas into the vacuum vessel and ejecting the ionized fluorine-containing gas from the ion milling source; Irradiating the substrate with the ionized fluorine-containing gas.

1. A vacuum processing method comprising: The fluorine-resistant material includes at least one of aluminum-containing graphite and silicon-added aluminum-containing graphite. Vacuum processing method.

6. 6. The vacuum processing method according to claim 5, The ionized fluorine-containing gas is accelerated with a voltage of 0.5 KeV to 5 KeV and irradiated onto the substrate. Vacuum processing method.

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