Exhaust network manufacturing method, plasma processing apparatus and exhaust network

Abstract

To provide a technique that can strike a balance between exhaust performance and discharge stability.SOLUTION: The present invention provides a method for producing an exhaust net that allows a gas to pass through it when the gas is exhausted from a treatment vessel of a plasma treatment device. The method includes the steps of (a) preparing a plurality of metal plates, (b) forming a honeycomb structure including a plurality of adjacent hexagonal through-holes in each of the plurality of metal plates, making a plurality of thin honeycomb nets, (b) layering the thin honeycomb nets to bring the through-holes of the thin honeycomb nets into communication with each other and joining together the thin honeycomb nets, to make a thickened exhaust net.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing an exhaust network, a plasma processing apparatus, and an exhaust network. [Background technology]

[0002] Patent Document 1 discloses a plasma processing apparatus that introduces gas into a processing vessel, converts the gas into plasma, and performs processing such as etching on a substrate. Gas generated during this processing is exhausted from inside the processing vessel to an exhaust section (exhaust mechanism). To prevent the plasma from entering the exhaust section, the plasma processing apparatus includes an exhaust mesh (mesh member) made of metal and connected to a ground potential. The exhaust mesh has a plurality of circular through holes that penetrate the thickness of the exhaust mesh.

[0003] In this type of exhaust network, the larger the aperture ratio of each through hole, the easier it is to exhaust gas, but the greater the likelihood of abnormal discharge occurring due to the intrusion of plasma. In other words, there is a trade-off between the exhaust performance and discharge stability of the exhaust network. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-188194 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a technique that can achieve both exhaust performance and discharge stability. [Means for solving the problem]

[0006] One aspect of the present disclosure is a method for manufacturing an exhaust network through which a gas passes when exhausting the gas from a processing container of a plasma processing apparatus, comprising: the exhaust network is made of stainless steel and is grounded via at least one of a lower chamber having an exhaust port of the processing vessel and an exhaust pipe connected to the exhaust port; (a) preparing a plurality of metal plates; (b) forming a plurality of hexagonal through holes on the metal plates; Intersect at intervals ranging from 0.3mm to 0.4mmThe present invention provides a method for manufacturing an exhaust network, comprising the steps of: (a) forming adjacent honeycomb structures on each of the plurality of metal plates to obtain a plurality of thin honeycomb networks; and (b) stacking the plurality of thin honeycomb networks so that the plurality of through holes of the plurality of thin honeycomb networks are interconnected, and joining the plurality of thin honeycomb networks together to produce a thicker exhaust network. Effect of the Invention

[0007] According to one embodiment, it is possible to achieve both exhaust performance and discharge stability. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view illustrating an example of a plasma processing apparatus according to an embodiment. [Diagram 2] 2 is an enlarged schematic cross-sectional view showing a portion where gas is exhausted from the processing vessel in FIG. 1. [Diagram 3] FIG. 2 is a perspective view showing an exhaust mesh according to an embodiment. [Figure 4] FIG. 2 is an explanatory diagram showing an enlarged view of a honeycomb structure of an exhaust network according to an embodiment. [Diagram 5] 1A to 1C are process explanatory diagrams showing a method for manufacturing an exhaust network according to one embodiment. [Figure 6] FIG. 10 is an explanatory diagram showing the results of an experiment to confirm the exhaust performance of an exhaust network according to one embodiment. [Figure 7] 11 is a table showing discharge stability with respect to changes in pressure inside a processing chamber and changes in plasma output according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and duplicated descriptions may be omitted.

[0010] Fig. 1 is a schematic cross-sectional view showing an example of a plasma processing apparatus according to an embodiment. As shown in Fig. 1, an exhaust network 100 according to an embodiment is applied to a plasma processing apparatus 1. In the following, in order to facilitate understanding of the present invention, the configuration of the plasma processing apparatus 1 will be described first.

[0011] The plasma processing apparatus 1 is an inductively coupled plasma (ICP) processing apparatus that performs various substrate processing on a substrate for FPD (hereinafter, simply referred to as substrate G). Examples of FPDs manufactured by processing the substrate G include liquid crystal displays (LCD), electroluminescence (EL), and plasma display panels (PDP). In this case, glass or synthetic resin is used as the material for the substrate G. The substrate G may include a substrate having a circuit patterned on its surface, or a support substrate without a circuit. The planar dimensions of the substrate G are preferably in the range of about 1800 mm to 3400 mm for the long side and about 1500 mm to 3000 mm for the short side. The thickness of the substrate G is preferably in the range of about 0.2 mm to 4.0 mm. Substrate processing performed by the plasma processing apparatus 1 includes a film formation process using a CVD (Chemical Vapor Deposition) method, an etching process, and the like. The following describes a plasma processing apparatus 1 that performs a film formation process as a substrate process.

[0012] The plasma processing apparatus 1 includes a rectangular parallelepiped box-shaped processing vessel 10. The processing vessel 10 is made of a metal such as aluminum or an aluminum alloy. The processing vessel 10 may be formed into an appropriate shape depending on the shape of the substrate G. For example, when the substrate G is a disk or an elliptical plate, the processing vessel 10 is preferably formed into a cylindrical shape, an elliptical cylindrical shape, or the like.

[0013] The processing vessel 10 is provided with a rectangular support frame 11 that protrudes inwardly of the processing vessel 10 at a predetermined vertical position, and this support frame 11 supports a dielectric plate 12 in the horizontal direction. The processing vessel 10 is divided into an upper chamber 13 and a lower chamber 14, with the dielectric plate 12 in between. The upper chamber 13 forms an antenna chamber 13a inside. The lower chamber 14 accommodates a substrate G and forms an internal space 14a inside where the substrate is processed.

[0014] A side wall 15 of the lower chamber 14 is provided with a transfer port 17 that is opened and closed by a gate valve 16. When the gate valve 16 is open, the plasma processing apparatus 1 transfers the substrate G into and out of the plasma processing apparatus 1 through the transfer port 17 by a transfer device (not shown).

[0015] In addition, the side walls 15 of the lower chamber 14 are grounded (connected to a ground potential) via a ground wire 18. The four side walls 15 of the lower chamber 14 have an endless circumferential seal groove 19 at their upper ends. A seal member 20 such as an O-ring is disposed in the seal groove 19, so that the support frame 11 and the lower chamber 14 air-tightly seal the internal space 14a.

[0016] The support frame 11 is made of a metal such as aluminum or an aluminum alloy, etc. The dielectric plate 12 is made of a ceramic such as alumina (Al2O3) or quartz.

[0017] A shower head 21, which is connected to the support frame 11 and is made of a plurality of elongated members and ejects gas into the internal space 14a, is provided inside the support frame 11 and also serves as a support beam for supporting the dielectric plate 12. The dielectric plate 12 is supported on the upper surface of the shower head 21. The shower head 21 is preferably made of a metal such as aluminum and has been subjected to a surface treatment by anodization. A gas flow path 21a is formed inside the shower head 21 along the horizontal direction. The shower head 21 also has a plurality of gas ejection holes 21b that communicate the gas flow path 21a with the lower surface (internal space 14a) of the shower head 21.

[0018] A gas introduction pipe 22 communicating with the gas flow path 21a is connected to the upper surface of the shower head 21. The gas introduction pipe 22 extends upward within the upper chamber 13, penetrates the upper chamber 13, and is connected to a gas supply unit 23 provided outside the processing vessel 10.

[0019] The gas supply unit 23 has a gas supply pipe 24 connected to the gas introduction pipe 22, and is provided with, in this order from upstream to downstream of the gas supply pipe 24, a gas supply source 25, a mass flow controller 26, and an on-off valve 27. In the film forming process, a gas is supplied from the gas supply source 25, the flow rate is controlled by the mass flow controller 26, and the supply timing is controlled by the on-off valve 27. This gas flows from the gas supply pipe 24 through the gas introduction pipe 22 into the gas flow path 21a, and is discharged into the internal space 14a through each gas discharge hole 21b.

[0020] A high-frequency antenna 28 is installed in the upper chamber 13 that forms the antenna room 13a. The high-frequency antenna 28 is formed by wiring an antenna wire made of a conductive metal such as copper in a circular or spiral shape. Alternatively, the high-frequency antenna 28 may be a multiplexed arrangement of circular antenna wires. A power supply member 29 extending upward within the upper chamber 13 is connected to a terminal of the high-frequency antenna 28.

[0021] The power supply member 29 has an upper end that protrudes outside the processing vessel 10, and a power supply line 30 is connected to this upper end. The power supply line 30 is connected to a high frequency power source 32 via a matching device 31 that performs impedance matching. The high frequency power source 32 applies high frequency power of a frequency (e.g., 13.56 MHz) according to the substrate processing to the high frequency antenna 28. As a result, the high frequency antenna 28 forms an induced electric field in the lower chamber 14.

[0022] The processing vessel 10 includes a stage 40 (mounting table) for mounting the substrate G loaded from the load / unload port 17 in the lower chamber 14. The stage 40 has a stage body 41, a pedestal 42, a plurality of lift pins 43, and a plurality of lift pin lifting mechanisms 44. The substrate G loaded into the lower chamber 14 is transferred to each of the lift pins 43 raised by each of the lift pin lifting mechanisms 44, and is mounted on the stage body 41 by lowering each of the lift pins 43.

[0023] The stage main body 41 is formed in a rectangular shape in a plan view, and has a mounting surface 411 with planar dimensions approximately equal to those of the substrate G. For example, the planar dimensions of the mounting surface 411 may be such that the long side is in the range of approximately 1800 mm to 3400 mm, and the short side is in the range of approximately 1500 mm to 3000 mm.

[0024] A plasma processing space PCS is formed between the mounting surface 411 of the stage body 41 and the shower head 21. In the plasma processing space PCS, plasma is generated by converting the gas supplied from the shower head 21 to the internal space 14a into plasma due to an induction electric field formed by the high frequency antenna 28. The plasma processing apparatus 1 provides the substrate G with a film formation precursor in the plasma generated in the plasma processing space PCS.

[0025] The stage body 41 is formed of aluminum, an aluminum alloy, or the like, and includes a heater wire 45 therein, which is a resistor. The heater wire 45 is connected to a heater driver 46, and is heated based on the power supply from the heater driver 46. The heater driver 46 is connected to a control unit 60 of the plasma processing apparatus 1, and outputs power according to a temperature command from the control unit 60. Furthermore, the stage body 41 may include a cooling mechanism to enable precise temperature control. For example, when performing substrate processing (film formation processing), the plasma processing apparatus 1 heats the mounting surface 411 of the stage 40 to about 200° C. and maintains that temperature state.

[0026] The pedestal 42 is made of an insulating material, and is disposed on the bottom plate 33 of the lower chamber 14 to support the stage body 41. The pedestal 42 has an opening at the bottom, and fixes and supports the stage body 41 in a state in which the stage body 41 is spaced apart from the bottom plate 33.

[0027] The plasma processing apparatus 1 has a control unit 60 that controls the operation of the entire apparatus. The control unit 60 is a control computer that includes one or more processors 61, a memory 62, an input / output interface (not shown), and an electronic circuit. The memory 62 includes a non-volatile memory and a volatile memory, and forms a storage unit of the control unit 60 that stores programs and recipe data. A part of the memory 62 may be built into the processor 61. An input / output device (not shown) of the plasma processing apparatus 1 is connected to the input / output interface. Examples of the input / output device include a touch panel, a monitor, and a keyboard. The one or more processors 61 may be one or a combination of a CPU, an ASIC, an FPGA, a circuit made of a plurality of discrete semiconductors, and the like. The one or more processors 61 execute the program in the memory 62, and perform plasma processing on the substrate G according to the recipe data.

[0028] The plasma processing apparatus 1 has an exhaust port 14b in the bottom plate 33 of the processing vessel 10 for exhausting gas from the internal space 14a, and includes an exhaust unit 70 connected to the processing vessel 10 via the exhaust port 14b. Although one exhaust port 14b and one exhaust unit 70 are illustrated in FIG. 1, the plasma processing apparatus 1 may include a plurality of exhaust ports 14b and exhaust units 70.

[0029] Exhaust port 14b is formed in a perfect circle shape and is provided between the side wall of processing vessel 10 and stage 40. The diameter of exhaust port 14b depends on the size of processing vessel 10, but is preferably set in the range of about 200 mm to 400 mm, for example, and is set to 300 mm in this embodiment. Note that the shape of exhaust port 14b does not necessarily have to be a perfect circle depending on the arrangement position, and may be a semicircular shape or other shape depending on the arrangement position.

[0030] Fig. 2 is an enlarged schematic cross-sectional view of exhaust port 14b (gas exhaust port) that exhausts gas from processing vessel 10. As shown in Fig. 2, exhaust unit 70 includes an exhaust pipe 71 connected to exhaust port 14b, and an exhaust mechanism 72 provided in exhaust pipe 71 to exhaust gas (e.g., volatile gas) inside processing vessel 10.

[0031] The exhaust pipe 71 is a pipe having a circular cross section and an internal passage 71a communicating with the exhaust port 14b, and is made of an appropriate metal. The exhaust pipe 71 may extend linearly downward as shown in FIG. 2, or may be curved or bent at an intermediate position. As described above, the processing vessel 10 is grounded, and thus the exhaust pipe 71 connected to the processing vessel 10 is also grounded. The inner peripheral surface of the exhaust pipe 71 forming the passage 71a is preferably coated to suppress corrosion of the exhaust pipe 71.

[0032] 1 and 2, exhaust mechanism 72 includes, in this order downstream in the gas flow direction of exhaust pipe 71, an APC (Automatic Pressure Control) valve 73, a turbo molecular pump (TMP) 74, and a dry pump 75. Exhaust mechanism 72 rough pumps the inside of processing vessel 10 with dry pump 75, and then evacuates the inside of processing vessel 10 with turbo molecular pump 74. In addition, exhaust mechanism 72 controls the pressure in internal space 14a by adjusting the aperture of APC valve 73.

[0033] The exhaust network 100 may be disposed in contact with the exhaust pipe 71 or the lower chamber 14 in the plasma processing apparatus 1 between the stage 40 (mounting table) and the inlet side of the APC valve 73 of the exhaust mechanism 72 of the exhaust pipe 71 via the exhaust port 14b. The exhaust network 100 is at ground potential by contacting the exhaust pipe 71 or the lower chamber 14, which are at ground potential. This allows the exhaust network 100 to block plasma and prevent it from entering the APC valve 73, turbo molecular pump 74, and the like. More preferably, the exhaust network 100 is disposed closer to the exhaust port 14b than the inlet side of the APC valve 73, or at a position (exit side, inlet side) near the exhaust port 14b so that a part of the exhaust network 100 is in contact with the lower chamber 14. By disposing the exhaust network 100 at a position near the exhaust port 14b, it is possible to avoid discharge due to the intrusion of plasma into the exhaust pipe 71. In addition, the exhaust network 100 can prevent components from falling to the APC valve 73 in the exhaust pipe 71.

[0034] In the plasma processing apparatus 1 according to the present embodiment, the exhaust network 100 is disposed at a position adjacent to the outlet side of the exhaust port 14b at the connection end of the exhaust pipe 71 on the exhaust port 14b side. Alternatively, the exhaust network 100 may be disposed on the inlet side of the exhaust port 14b. The exhaust network 100 may be disposed on the inlet side of the exhaust port 14b so as to contact the lower chamber 14, or may be disposed inside the exhaust port 14b (between the outlet side and the inlet side) so as to contact the lower chamber 14. Alternatively, the exhaust network 100 may be disposed in the internal space 14a above the exhaust port 14b so as to contact the lower chamber 14 directly or indirectly with electrical conduction. In addition to the exhaust network 100 in the exhaust pipe 71 (or the exhaust port 14b), the plasma processing apparatus 1 may also be provided with a baffle plate (not shown) in the processing vessel 10. If the exhaust network 100 is not in electrical contact with the lower chamber 14 and also not in contact with the exhaust pipe 71 and is therefore not at ground potential, the effect of the exhaust network 100 in blocking plasma is weakened.

[0035] Fig. 3 is a perspective view showing the exhaust net 100. As shown in Fig. 3, the exhaust net 100 is formed in a perfect circular shape in a plan view. The diameter of the exhaust net 100 is preferably set in the range of about 200 mm to 400 mm. In this embodiment, an exhaust net 100 having a diameter of 300 mm is applied in accordance with the size of the exhaust port 14b.

[0036] 2 and 3, exhaust mesh 100 includes a ring-shaped outer frame portion 101 and an inner portion 102 that allows gas to flow inside outer frame portion 101. Note that exhaust mesh 100 may be formed only by inner portion 102 having honeycomb structure 104, without providing outer frame portion 101. In addition, exhaust pipe 71 and exhaust mesh 100 are fixed to exhaust pipe 71 by engagement structure 76 so that exhaust mesh 100 can be detached from exhaust pipe 71.

[0037] For example, the engagement structure 76 is provided at a connection end (upper end) of the exhaust pipe 71 that is connected to the processing vessel 10. The inner diameter of the exhaust pipe 71 is set to be substantially the same as the diameter of the inner portion 102, and the connection end of the exhaust pipe 71 is provided with a flange portion 77 that expands radially outward in correspondence with the outer frame portion 101. The exhaust pipe 71 is fixed to the bottom plate 33 of the processing vessel 10 by a connecting means such as a screw, in a state in which the outer frame portion 101 of the exhaust mesh 100 is placed on the flange portion 77. Thereby, in the plasma processing apparatus 1, the exhaust mesh 100 can be disposed at a position adjacent to the exhaust port 14b of the processing vessel 10 with the connection of the exhaust pipe 71. In addition, the inner portion 102 is disposed to face the passage 71a in the exhaust pipe 71 when the exhaust pipe 71 is disposed.

[0038] The outer frame 101 and the inner portion 102 are continuous with each other through a metal mainly composed of stainless steel (e.g., SUS304) or aluminum. The surface of the exhaust network 100 may be coated with ceramics such as yttria (Y2O3). The ceramic coating can provide the exhaust network 100 with plasma resistance. However, the ceramic coating needs to be kept to a thickness that allows the exhaust network 100 to function as a ground potential in the RF circuit. The exhaust network 100, which is made of metal and fixed to the exhaust pipe 71, is grounded (connected to a ground potential) via the exhaust pipe 71 and the processing vessel 10.

[0039] FIG. 4 is an explanatory diagram in which the honeycomb structure 104 of the exhaust network 100 is enlarged. FIG. 4(a) is a partial plan view of the inner portion 102 of the exhaust network 100, and FIG. 4(b) is a partial cross-sectional view taken along line IV-IV in (a). The inner portion 102 of the exhaust network 100 is formed in a plate shape, and a honeycomb structure 104 is formed by arranging a plurality of hexagonal (regular hexagonal) through holes 103 adjacent to each other while sharing sides. That is, as shown in FIG. 4(a), the inner portion 102 has a plurality of through holes 103 and a plurality of hole sides 105 surrounding each of the plurality of through holes 103. Note that each through hole 103 may have a hexagonal shape other than a regular hexagonal shape (for example, a flattened hexagonal shape).

[0040] The through holes 103 of the honeycomb structure 104 are arranged in a direction in which the sides 105 of the holes are arranged in parallel to each other (a direction perpendicular to the longitudinal direction of the sides 105 of the holes), thereby forming a mesh of the exhaust network 100. The sides 105 of the holes are elongated compared to the size of the through holes 103, and extend linearly with a constant width. Furthermore, the sides 105 of the holes are formed to have the same length according to the hexagonal through holes 103, and are connected to each other at an angle of 120°. By having such a plurality of through holes 103 and a plurality of sides 105 of the holes, the aperture ratio of the inner portion 102 (exhaust network 100) is set to 85% or more. In other words, the honeycomb structure 104 significantly increases the aperture ratio of the inner portion 102 of the exhaust network 100, and gas can easily flow from the exhaust port 14b to the passage 71a.

[0041] 4(b), the exhaust network 100 is formed by stacking a plurality of thin plates (hereinafter referred to as thin honeycomb networks 110) having honeycomb structures 104 together and bonding the plurality of thin honeycomb networks 110 together using a manufacturing method described below. Therefore, the exhaust network 100 has a configuration in which a plurality of thin honeycomb networks 110 are bonded together in the thickness direction (bonding portion 106).

[0042] The joint 106 is produced by an appropriate joining means in the manufacturing method. For example, the joint 106 is in a state where atoms of the lower thin honeycomb network 110 and atoms of the upper thin honeycomb network 110 diffuse into each other at the interface between them by diffusion bonding, while crossing the interface to form new crystal grains. The joint 106 is not limited to diffusion bonding, and may be a joint between the lower thin honeycomb network 110 and the upper thin honeycomb network 110 by bonding means such as adhesion, welding, and pressure bonding, as long as the bonding can maintain electrical conduction between the lower thin honeycomb network 110 and the upper thin honeycomb network 110.

[0043] The thickness ts (plate thickness: dimension in the thickness direction) of the thin honeycomb mesh 110 is preferably set according to the width We of the hole sides 105 (spacing between two adjacent through holes 103) described below, and may be, for example, the same as the width We of the hole sides 105 or slightly shorter than the width We of the hole sides 105. The thickness ts of the thin honeycomb mesh 110 according to this embodiment is set to 0.4 mm.

[0044] The width We of the multiple hole sides 105 is determined by the frequency f of the high frequency wave and the relative permeability μ r It is preferable to set the value to be equal to or greater than the skin depth δ in the following formula (1) using the magnetic permeability μ0 and electrical conductivity σ of a vacuum in order to facilitate the flow of high-frequency power along the inner wall surface of through-hole 103 formed by hole sides 105.

[0045] δ = 1 / (π × f × μ r ×μ0×σ) 1 / 2 (1)

[0046] As an example, assuming that SUS304 is used as the material of the thin honeycomb net 110 and that the frequency of the high frequency power is 3.2 MHz, the skin depth δ in formula (1) is 0.27 mm. Therefore, the width We of the hole side 105 (the interval between the through holes 103) is set to a value of 0.3 mm or more. This makes it easier for the high frequency power to flow through the inner wall surface of the through holes 103 of the exhaust net 100 formed by joining the thin honeycomb nets 110, and the high frequency power can be passed to the ground through the exhaust net 100. As a result, it is possible to prevent abnormal discharge from occurring in the exhaust net 100. For example, the width We of the hole side 105 may be set in the range of about 0.3 mm to 1.0 mm. However, if the width We of the hole side 105 is widened, the aperture ratio decreases, the conductance decreases, and the gas exhaust efficiency decreases. Therefore, the width We of the hole side 105 is preferably 0.4 mm or less. From the above, in order to achieve both exhaust performance and discharge stability, it is more preferable to set the interval between the through holes 103 of the thin honeycomb mesh 110 in the range of 0.3 mm or more and 0.4 mm or less.

[0047] The width We of the hole sides 105 according to this embodiment is 0.4 mm. That is, the hole sides 105 of the thin honeycomb net 110 have a substantially square shape with a thickness ts of 0.4 mm and a width We of 0.4 mm in a cross section perpendicular to the extension direction of the hole sides 105.

[0048] The number of stacked thin honeycomb nets 110 constituting the exhaust net 100 may be designed as desired, and is preferably within a range of, for example, 2 to 15 sheets, and is set to 10 sheets in this embodiment. That is, the overall thickness T of the exhaust net 100 formed by stacking a plurality of thin honeycomb nets 110 is preferably set to a range of about 0.8 mm to 6.0 mm, and is 4.0 mm in this embodiment. By setting the thickness T of the exhaust net 100 to 0.8 mm or more, it is possible to suppress the plasma from entering the APC valve 73 side.

[0049] The size of each through hole 103 of the exhaust network 100 is set so that the length E of the line connecting two opposing vertices of the hexagonal shape of each through hole 103 is shorter than the wavelength of the high frequency wave in order to suppress the intrusion of plasma generated by high frequency power in the processing vessel 10. Moreover, each through hole 103 is preferably set to a size smaller than the components (e.g., M4 screws) used in the processing vessel 10 in order to prevent the components from falling off. As an example, the distance D between a pair of hole sides 105 extending in parallel across each through hole 103 (the width of the through hole 103) is preferably set to a range of about 3.0 mm to 7.0 mm, and is set to 4.77 mm (= 3 / 16 inch) in this embodiment.

[0050] Furthermore, when the distance D between the hole sides 105 is 4.77 mm, when the thickness T of the exhaust network 100 is 2.0 mm, the discharge becomes unstable, and when the thickness T is 4.0 mm, the exhaust characteristics become poor. For this reason, it is preferable that the width of the through hole 103 (the distance D between a pair of hole sides 105) is in the range of 1.4 to 2.0 times the thickness T of the exhaust network 100. If the width of the through hole 103 is smaller than 1.4 times the thickness T of the exhaust network 100, the aperture ratio decreases, and it becomes more likely that the gas will not flow easily. On the other hand, if the width of the through hole 103 is larger than 2.0 times the thickness T of the exhaust network 100, the aperture ratio increases, but plasma passes through the exhaust network 100, making it more likely that abnormal discharge will occur.

[0051] Furthermore, the ratio of the width We of the hole sides 105 to the width of the through-hole 103 (the distance D between a pair of hole sides 105) is preferably in the range of about 1 / 15 to 1 / 8. If this ratio is less than 1 / 15, the plasma discharge stability and mechanical strength of the exhaust network 100 may decrease, and if this ratio is more than 1 / 8, the aperture ratio may decrease.

[0052] 5 is a process explanatory diagram showing a manufacturing method of the exhaust mesh 100. Next, the manufacturing method of the exhaust mesh 100 will be described with reference to FIG.

[0053] In manufacturing the exhaust mesh 100, the manufacturer performs a preparation step, a plate processing step, and a joining step in this order.

[0054] The preparation process is a process of preparing a plurality of metal plates 120 that will be the base material of the thin honeycomb mesh 110, and the manufacturer prepares the plurality of metal plates 120 by molding, purchasing, etc. In this embodiment, the plurality of metal plates 120 are stainless steel (SUS) plates and have the same thickness as the thickness ts of the thin honeycomb mesh 110 to be formed. In the preparation process, the desired thickness ts may be obtained by performing appropriate processing (e.g., pressing) on ​​a plate material having a thickness different from the thickness ts of the thin honeycomb mesh 110 to be formed.

[0055] The plate processing step is a step of manufacturing a thin honeycomb network 110 having a honeycomb structure 104 by forming a plurality of through holes 103 in a metal plate 120. For example, in the plate processing step, each of the plurality of metal plates 120 is etched.

[0056] An example of an apparatus for etching the metal plate 120 is an etching apparatus (not shown) for performing wet etching. In this case, the manufacturer inputs a processing recipe for the honeycomb structure 104 having a plurality of through holes 103 into the etching apparatus, and sets the metal plate 120 in the etching apparatus. A mask for each hole side 105 of the honeycomb structure 104 is formed on the metal plate 120 in advance, and the metal plate 120 is further immersed in the etching solution of the etching apparatus to form the through holes 103 at the portions exposed from the mask. Although burrs may be generated in mechanical processing such as punching, by performing etching in this manner in the plate processing step, it is possible to suppress the generation of processing marks such as burrs on the metal plate 120. Note that the plate processing step is not limited to etching, and the plurality of through holes 103 may be formed in each metal plate 120 by other processing methods as long as they do not generate burrs. In addition, the outer peripheral shape of the thin honeycomb mesh 110 may be formed at the same time as the formation of the through holes 103 by the above-mentioned wet etching, or the metal plate 120 may be processed into the outer peripheral shape of the thin honeycomb mesh 110 beforehand prior to the formation of the through holes 103.

[0057] The joining process is a process for manufacturing a thickened exhaust net 100 by stacking a plurality of thin honeycomb nets 110 formed in the plate processing process and joining the plurality of thin honeycomb nets 110 together. At this time, the manufacturer stacks the thin honeycomb nets 110 while positioning the thin honeycomb nets 110 so that the through holes 103 of the plurality of thin honeycomb nets 110 communicate with each other. For example, at a location where the plurality of thin honeycomb nets 110 are stacked (e.g., a workbench for the joining process, etc.), several pins (not shown) slightly smaller than the hexagonal through holes 103 stand up, and the through holes 103 are inserted into each of these pins to position the thin honeycomb nets 110 relative to each other.

[0058] Furthermore, for example, a method for bonding multiple thin honeycomb networks 110 together includes diffusion bonding (including vacuum diffusion bonding or argon diffusion bonding). In this case, the manufacturer applies pressure and heat (hot press) to multiple stacked thin honeycomb networks 110 using a diffusion bonding device (not shown). As a result, metal atoms at the interfaces between the stacked thin honeycomb networks 110 diffuse and mix, eliminating voids, and new crystal grains of metal atoms (bonding portions 106) are formed across the interfaces to bond the thin honeycomb networks 110 together.

[0059] The exhaust network 100 manufactured by the above manufacturing method becomes a thick plate with a beautiful honeycomb structure 104 without burrs or steps. That is, the through holes 103 of the exhaust network 100 that has undergone the plate processing process and the joining process smoothly continue along the thickness direction of the exhaust network 100 (the stacking direction of the multiple thin plate honeycomb networks 110), maintaining a high aperture ratio of the multiple thin plate honeycomb networks 110. Therefore, the exhaust network 100 allows gas to stably pass through in the thickness direction, and an appropriate thickness T can suppress abnormal plasma discharge.

[0060] 6 is an explanatory diagram showing the results of an experiment to confirm the exhaust performance of the exhaust network. FIG. 6(a) shows a graph showing the exhaust performance of the exhaust network when the pressure inside the processing vessel 10 is adjusted to 10 mT (1.33 Pa). The horizontal axis represents the opening degree of the APC valve 73, and the vertical axis represents the supply flow rate [slm] of oxygen gas supplied to the processing vessel 10 by the mass flow controller 26. In other words, while the pressure inside the processing vessel 10 is being adjusted to 10 mT, the change in the supply flow rate of gas supplied into the processing vessel 10 corresponds to the exhaust amount of gas discharged from the processing vessel 10 to the exhaust section 70.

[0061] In the graph of Fig. 6(a), the solid line shows the change in flow rate when an exhaust network 100 having a honeycomb structure 104 according to this embodiment (hereinafter referred to as honeycomb exhaust network A) is applied. The dashed line shows the change in flow rate when an exhaust network having a plurality of round holes 130 according to a comparative example and a conventional technology (hereinafter referred to as round hole exhaust network B) is applied. Fig. 6(b) is an enlarged plan view illustrating the honeycomb exhaust network A used in the experiment. Fig. 6(c) is an enlarged plan view illustrating the round hole exhaust network B used in the experiment.

[0062] The size of each through hole 103 of the honeycomb exhaust network A (the distance D between a pair of hole sides 105) is 4.77 mm as described above, and in this case the opening rate of the entire honeycomb exhaust network A is 85.1%. In contrast, the diameter of each round hole 130 of the round hole exhaust network B is 5 mm, and the opening rate of the entire round hole exhaust network B is 62.9%. The diameter (outer diameter) of both the honeycomb exhaust network A and the round hole exhaust network B is 350 mm. The thickness of the honeycomb exhaust network A is 3 mm, and the thickness of the round hole exhaust network B is 2 mm.

[0063] As shown in FIG. 6(a), in both the honeycomb exhaust network A and the round hole exhaust network B, the gas supply flow rate to the processing vessel 10 increases as the opening degree of the APC valve 73 increases. In other words, since the pressure inside the processing vessel 10 is constant, the increase in the gas supply flow rate means that the exhaust volume increases. However, as the opening degree of the APC valve 73 increases, the gas supply flow rate of the honeycomb exhaust network A increases more than that of the round hole exhaust network B. For example, when the opening degree of the APC valve 73 is 400, the supply flow rate of the round hole exhaust network B is 4.55 [slm], while the supply flow rate of the honeycomb exhaust network A is 4.8 [slm]. In other words, the honeycomb exhaust network A exhausts more gas from the processing vessel 10 to the exhaust section 70 than the round hole exhaust network B, and it can be said that the exhaust performance of the honeycomb exhaust network A is superior to that of the round hole exhaust network B. Although some aspects of the experiment cannot be simply compared due to manufacturing constraints of each exhaust network, the ultimate consideration of the arrangement of hexagonal through holes 103 and the arrangement of round holes 130 can be considered as follows. In the case of hexagonal through holes 103, as the distance between the through holes 103 approaches 0, the aperture ratio approaches 100%. On the other hand, in the case of round holes 130, even if the distance between the round holes 130 approaches 0, there remains a margin between the openings of the three round holes 130, and the aperture ratio is limited to approximately 93%. This also shows that honeycomb exhaust network A has a better aperture ratio than round hole exhaust network B.

[0064] FIG. 7 is a table showing discharge stability in relation to changes in pressure in the processing vessel 10 and changes in plasma output. FIG. 7(a) shows a case where an exhaust network 100 (honeycomb exhaust network A) having a honeycomb structure 104 according to the present embodiment is applied, and FIG. 7(b) shows a case where an exhaust network (round hole exhaust network B) having a plurality of round holes 130 according to a comparative example is applied. The discharge stability is determined by visually observing the occurrence of abnormal discharge in the plurality of through holes 103 or the plurality of round holes 130. Specifically, when no light emission due to plasma occurs in each of the through holes 103 or each of the round holes 130, it is determined that there is discharge stability and OK is recorded. When light emission due to plasma occurs in the through holes 103 or the round holes 130, it is determined that there is no discharge stability and NG is recorded.

[0065] As shown in FIG. 7(b), the round-hole exhaust network B has discharge stability when the pressure in the processing vessel 10 is 15 mT (2.00 Pa) or less. On the other hand, the round-hole exhaust network B does not have discharge stability when the pressure in the processing vessel 10 is 20 mT (2.67 Pa) and the plasma output (high frequency power) is 11.1 kW or more. Furthermore, when the pressure in the processing vessel 10 is 25 mT (3.33 Pa) to 35 mT (4.67 Pa), abnormal discharge occurs at a plasma output of 5.5 kW or more. Furthermore, when the pressure in the processing vessel 10 is 40 mT (5.33 Pa), the round-hole exhaust network B loses discharge stability regardless of the plasma output.

[0066] In contrast, as shown in FIG. 7(a), the honeycomb exhaust network A does not generate abnormal discharge when the pressure of the processing vessel 10 is 20 mT (2.67 Pa) or less. The honeycomb exhaust network A does not have discharge stability when the pressure of the processing vessel 10 is 25 mT (3.33 Pa) and the plasma output (high frequency power) is 18.0 kW or more. The honeycomb exhaust network A does not have discharge stability when the pressure of the processing vessel 10 is 30 mT (4.00 Pa) and the plasma output is 8.3 kW or more. Furthermore, when the pressure of the processing vessel 10 is 35 mT (4.67 Pa) to 40 mT (5.33 Pa), the honeycomb exhaust network A does not have discharge stability when the plasma output is 5.5 kW or more. Therefore, the honeycomb exhaust network A has discharge stability at a low plasma output even when the pressure of the processing vessel 10 is 40 mT (5.33 Pa).

[0067] 7(a) and 7(b), the honeycomb exhaust network A is more likely to achieve discharge stability and has a larger discharge stability region than the round-hole exhaust network B. In other words, it can be said that the honeycomb exhaust network A is superior to the round-hole exhaust network B in terms of discharge stability.

[0068] As described above, the manufacturing method of the exhaust network 100 according to one embodiment of the present disclosure makes it possible to precisely form the honeycomb structure 104 in which a plurality of hexagonal through-holes 103 are arranged in the exhaust network 100. Since the opening ratio of the exhaust network 100 is significantly increased by the honeycomb structure 104, the exhaust network 100 can improve the exhaust performance when exhausting gas. Furthermore, in the manufacturing method of the exhaust network 100, a plurality of thin honeycomb nets 110 are joined together to form a thick plate. As a result, the exhaust network 100 reduces abnormal plasma discharge and further improves discharge stability. In other words, the exhaust network 100 can improve both the exhaust performance and the discharge stability.

[0069] Moreover, the opening ratio of the honeycomb structure 104 in the exhaust network 100 is 85% or more. This allows the exhaust network 100 to have further improved exhaust performance.

[0070] Furthermore, the distance between adjacent through holes 103 among the plurality of through holes 103 is in the range of 0.3 mm to 0.4 mm. This narrows the width We of the hole side 105 extending between the plurality of through holes 103 in the exhaust network 100, making it possible to further easily increase the aperture ratio.

[0071] Furthermore, the distance D between a pair of hole sides 105 extending in parallel with the multiple through holes 103 in between is in the range of 1.4 to 2.0 times the thickness T of the exhaust network 100. As a result, the exhaust network 100 can improve exhaust performance by increasing the size of the multiple through holes 103, while improving discharge stability by ensuring that the length of the through holes 103 along the thickness direction is sufficient.

[0072] In the bonding process, the thin honeycomb nets 110 are bonded together by diffusion bonding. As a result, the manufacturing method for the exhaust net 100 can stably manufacture the exhaust net 100 in which the thin honeycomb nets 110 are firmly fixed together and burrs and steps are suppressed.

[0073] In the plate processing step, the metal plates 120 are each wet-etched via a plurality of honeycomb-shaped masks to form a plurality of through-holes 103. This enables the manufacturing method for the exhaust mesh 100 to form the thin honeycomb mesh 110 efficiently and accurately.

[0074] Moreover, a plasma processing apparatus 1 for performing plasma processing on a substrate G according to an embodiment of the present disclosure includes a processing vessel 10 having a mounting table (stage 40) on which a substrate G is mounted, an exhaust pipe 71 connected to an exhaust port 14b provided in the processing vessel 10, an exhaust mechanism 72 provided in the exhaust pipe 71 for exhausting gas in the processing vessel 10, and an exhaust network 100 provided at a position from the stage 40 to the exhaust mechanism 72 of the exhaust pipe 71 via the exhaust port 14b, the exhaust network 100 having a honeycomb structure 104 with a plurality of hexagonal through holes 103 adjacent to each other, and having a configuration in which a plurality of thin honeycomb nets 110 are joined in the thickness direction to form a thick plate. This allows the plasma processing apparatus 1 to improve exhaust performance and discharge stability.

[0075] Moreover, the exhaust network 100 has a configuration in which a plurality of thin honeycomb nets 110 are bonded together by diffusion bonding. As a result, the exhaust network 100 having the bonded portions 106 can be made thicker while suppressing burrs and steps, and the exhaust performance and discharge stability can be further improved.

[0076] Further, the position where the exhaust network 100 is provided is a position where the exhaust port 14b is covered by the exhaust network 100. By covering the exhaust port 14b with the exhaust network 100, the plasma processing apparatus 1 can effectively suppress the intrusion of plasma into the exhaust pipe 71 connected downstream of the exhaust network 100.

[0077] Moreover, an exhaust network according to one embodiment of the present disclosure is an exhaust network 100 provided in a plasma processing apparatus 1 that performs plasma processing on a substrate G, and has a honeycomb structure 104 in which a plurality of hexagonal through-holes 103 are adjacent to each other, and is thickened by having a configuration in which a plurality of thin honeycomb nets 110 are joined in the thickness direction. As a result, the exhaust network 100 can improve the exhaust performance and discharge stability of the plasma processing apparatus 1.

[0078] The exhaust mesh 100 has a configuration in which a plurality of thin honeycomb meshes 110 are bonded together by diffusion bonding. This allows the exhaust mesh 100 to be made thicker while suppressing burrs and steps.

[0079] The manufacturing method of the exhaust network 100, the plasma processing apparatus 1, and the exhaust network 100 according to the embodiments disclosed herein are illustrative and not restrictive in all respects. The embodiments can be modified and improved in various forms without departing from the scope and spirit of the appended claims. The matters described in the above embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent.

[0080] The plasma processing apparatus 1 of the present disclosure can be applied to any type of apparatus for PE-ALD (Plasma Enhanced Atomic Layer Deposition), PE-CVD (Plasma Enhanced Chemical Vapor Deposition), and dry etching. The objects to be plasma processed by the plasma processing apparatus 1 include, for example, a G6 substrate having a size of 1.5 m×1.85 m and rectangular substrates having other dimensions, but are not limited thereto, and may be various members such as a disk-shaped wafer. [Explanation of symbols]

[0081] 1. Plasma processing equipment 10 Processing vessel 14b Exhaust port 40 Stages 71 Exhaust pipe 72 Exhaust system 100 Exhaust Net 103 Through hole 104 Honeycomb structure 106 Joint 110 Thin honeycomb mesh 120 metal plate G board

Claims

1. A method for manufacturing an exhaust network through which a gas passes when the gas is exhausted from a processing vessel of a plasma processing apparatus, comprising the steps of: the exhaust network is made of stainless steel and is grounded via at least one of a lower chamber having an exhaust port of the processing vessel and an exhaust pipe connected to the exhaust port; (a) providing a plurality of metal plates; (b) forming a honeycomb structure in each of the plurality of metal plates, in which a plurality of hexagonal through holes are adjacent to each other at intervals in the range of 0.3 mm to 0.4 mm, to obtain a plurality of thin plate honeycomb networks; (c) stacking the plurality of thin honeycomb nets so that the plurality of through holes of the plurality of thin honeycomb nets are mutually connected, and bonding the plurality of thin honeycomb nets together to produce the thickened exhaust net, A method for manufacturing an exhaust network comprising the steps of:

2. The opening ratio of the honeycomb structure in the exhaust network is 85% or more. A method for manufacturing an exhaust network according to claim 1.

3. The distance between a pair of hole sides extending parallel to each other across the plurality of through holes is in the range of 1.4 to 2.0 times the thickness of the exhaust net.

3. A method for manufacturing an exhaust network according to claim 1 or 2.

4. In the step (c), the plurality of thin honeycomb networks are bonded to each other by diffusion bonding. A method for manufacturing an exhaust network according to any one of claims 1 to 3.

5. In the step (b), the plurality of through holes are formed by performing wet etching on each of the plurality of metal plates via a plurality of honeycomb-shaped masks. A method for manufacturing an exhaust network according to any one of claims 1 to 4.

6. A plasma processing apparatus for plasma processing a substrate, comprising: a processing vessel including a mounting stage for mounting the substrate; an exhaust pipe connected to an exhaust port provided in the processing vessel; an exhaust mechanism provided in the exhaust pipe for exhausting gas from within the processing vessel; an exhaust net provided at a position between the mounting table, the exhaust port, and the exhaust mechanism of the exhaust pipe; The exhaust network includes: a lower chamber having an exhaust port of the processing vessel and being grounded via at least one of the exhaust pipe and the lower chamber; Furthermore, the honeycomb structure has a plurality of hexagonal through holes adjacent to each other at intervals of 0.3 mm to 0.4 mm, and a plurality of thin honeycomb nets are joined in the thickness direction to form a thick plate.

2. A plasma processing apparatus comprising:

7. The exhaust network has a configuration in which the plurality of thin honeycomb networks are bonded together by diffusion bonding.

7. The plasma processing apparatus according to claim 6,

8. The position where the exhaust net is provided is a position where the exhaust port is covered by the exhaust net.

8. The plasma processing apparatus according to claim 6, wherein the plasma processing apparatus is a plasma processing apparatus.

9. An exhaust network provided in a plasma processing apparatus having a processing chamber for performing plasma processing on a substrate, comprising: The exhaust network is: a lower chamber formed of stainless steel and having an exhaust port of the processing vessel and an exhaust pipe connected to the exhaust port; and Furthermore, the honeycomb structure has a plurality of hexagonal through holes adjacent to each other at intervals of 0.3 mm to 0.4 mm, and a plurality of thin honeycomb nets are joined in the thickness direction to form a thick plate. An exhaust network characterized by:

10. The exhaust network has a configuration in which the plurality of thin honeycomb networks are bonded together by diffusion bonding.

10. An exhaust network as claimed in claim 9.

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