Method for manufacturing exhaust screen, plasma processing device and exhaust screen

Abstract

This invention provides a method for manufacturing an exhaust mesh, a plasma processing apparatus, and an exhaust mesh. The exhaust mesh is used to allow gas to pass through when it is discharged from the processing container of the plasma processing apparatus. The method for manufacturing the exhaust mesh is characterized by comprising: step a, preparing a plurality of metal plates; step b, forming a honeycomb structure consisting of a plurality of adjacent hexagonal through-holes on the plurality of metal plates to obtain a plurality of thin-plate honeycomb meshes; and step c, stacking the plurality of thin-plate honeycomb meshes in such a way that the plurality of through-holes are interconnected, and joining the plurality of thin-plate honeycomb meshes together to form the exhaust mesh, which is then formed into a thick plate. According to this invention, both exhaust performance and discharge stability can be achieved.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an exhaust screen, a plasma treatment apparatus, and an exhaust screen. Background Technology

[0002] Patent Document 1 discloses a plasma processing apparatus in which gas is introduced into a processing container to perform plasmaification and etching of a substrate. The gas generated during this process is discharged from the processing container to an exhaust section (exhaust mechanism). To suppress plasma intrusion into the exhaust section, the plasma processing apparatus has an exhaust mesh (mesh component) made of metal and connected to a ground potential. The exhaust mesh has multiple circular through holes extending through its thickness.

[0003] The larger the opening ratio of each through hole in this type of exhaust mesh, the easier it is for gas to escape; however, it also makes it more prone to abnormal discharges caused by plasma intrusion. In other words, the exhaust performance and discharge stability of the exhaust mesh are a trade-off.

[0004] Existing technical documents

[0005] Patent Literature

[0006] Patent document 1: Japanese Patent Application Publication No. 2020-188194. Summary of the Invention

[0007] The problem the invention aims to solve

[0008] This invention provides a technology that can simultaneously achieve exhaust performance and discharge stability.

[0009] Technical means for solving problems

[0010] One aspect of the present invention provides a method for manufacturing an exhaust screen, which is used to allow gas to pass through when gas is discharged from a processing container of a plasma processing device. The method for manufacturing the exhaust screen is characterized by comprising: step a, preparing a plurality of metal plates; step b, forming a honeycomb structure in the plurality of metal plates, each consisting of a plurality of hexagonal through holes arranged adjacently, to obtain a plurality of thin-plate honeycomb meshes; and step c, fabricating the exhaust screen, which is formed as a thick plate, by stacking the plurality of thin-plate honeycomb meshes in such a way that the plurality of through holes are interconnected, and joining the plurality of thin-plate honeycomb meshes together.

[0011] Invention Effects

[0012] One approach can balance exhaust performance and discharge stability. Attached Figure Description

[0013] Figure 1This is a cross-sectional schematic diagram illustrating an example of a plasma processing apparatus according to one embodiment.

[0014] Figure 2 It will be from Figure 1 A magnified cross-sectional diagram showing the part of the treatment container from which gas is discharged.

[0015] Figure 3 This is a perspective view of an exhaust screen according to one embodiment.

[0016] Figure 4 This is an enlarged illustration of the honeycomb structure of an exhaust screen according to one embodiment.

[0017] Figure 5 This is a step-by-step diagram illustrating a method for manufacturing an exhaust screen according to one embodiment.

[0018] Figure 6 This is an explanatory diagram showing the experimental results confirming the exhaust performance of an exhaust mesh according to one embodiment.

[0019] Figure 7 This is a table showing the discharge stability in response to changes in pressure within the processing container and changes in plasma output in one embodiment.

[0020] Explanation of reference numerals in the attached figures

[0021] 1. Plasma processing device

[0022] 10. Handling Containers

[0023] 14b Exhaust port

[0024] 40 mounting platforms

[0025] 71 Exhaust pipe

[0026] 72 Exhaust Mechanism

[0027] 100 Exhaust Net

[0028] 103 Through Hole

[0029] 104 Honeycomb Structure

[0030] 106 Joint

[0031] 110 Thin-plate honeycomb mesh

[0032] 120 metal sheet

[0033] G substrate Detailed Implementation

[0034] Hereinafter, the embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals are sometimes used to refer to the same structural parts, and repeated descriptions are omitted.

[0035] Figure 1 This is a cross-sectional schematic diagram illustrating one embodiment of a plasma processing apparatus. (e.g.) Figure 1 As shown, an exhaust screen 100 of one embodiment is applied to a plasma processing apparatus 1. Hereinafter, to facilitate understanding of the present invention, the structure of the plasma processing apparatus 1 will be described first.

[0036] The plasma processing apparatus 1 is an inductively coupled plasma (ICP) processing apparatus for performing various substrate processing on an FPD substrate (hereinafter referred to as substrate G). Examples of FPDs manufactured by processing substrate G include liquid crystal displays (LCDs), electroluminescent displays (ELs), and plasma display panels (PDPs). In this case, glass or synthetic resin can be used as the material for substrate G. Substrate G can include substrates with circuits patterned on their surface or support substrates without circuits. The planar dimensions of substrate G are preferably in the range of approximately 1800 mm to 3400 mm for the long side and approximately 1500 mm to 3000 mm for the short side. Furthermore, the thickness of substrate G is preferably in the range of approximately 0.2 mm to 4.0 mm. Examples of substrate processing performed by the plasma processing apparatus 1 include film deposition using CVD (Chemical Vapor Deposition) methods and etching processes. The plasma processing apparatus 1, used for film formation as substrate processing, will be described below.

[0037] The plasma processing apparatus 1 has a rectangular box-shaped processing container 10. The processing container 10 is formed of a metal such as aluminum or an aluminum alloy. In addition, the processing container 10 can be formed into an appropriate shape depending on the shape of the substrate G. For example, if the substrate G is a circular plate or an elliptical plate, the processing container 10 is preferably formed into a cylindrical or elliptical cylindrical shape.

[0038] The processing container 10 has a rectangular support frame 11 protruding inward at a predetermined position in the vertical direction, which supports the dielectric plate 12 in the horizontal direction. The processing container 10 is divided into an upper chamber 13 and a lower chamber 14 across the dielectric plate 12. An antenna chamber 13a is formed on the inner side of the upper chamber 13. The lower chamber 14 houses the substrate G and has an internal space 14a for substrate processing formed on its inner side.

[0039] The side wall 15 of the lower chamber 14 has an inlet / outlet 17 that is opened and closed by a gate 16. When the gate 16 is open, the plasma processing apparatus 1 feeds the substrate G in and out via the inlet / outlet 17 through a conveying device (not shown).

[0040] Additionally, the sidewall 15 of the lower chamber 14 is grounded (connected to the grounding potential) via a grounding wire 18. The sidewall 15 of the lower chamber 14 has an annular sealing groove 19 at its upper end. By arranging sealing components 20 such as O-rings in the sealing groove 19, the support frame 11 and the lower chamber 14 airtightly seal the internal space 14a.

[0041] The support frame 11 is made of metals such as aluminum or aluminum alloy. In addition, the dielectric plate 12 is made of ceramics such as alumina (Al2O3) or quartz.

[0042] Inside the support frame 11, a nozzle 21, which releases gas into the internal space 14a and is connected to the support frame 11 and is composed of multiple elongated components, is also provided as a support beam for the dielectric plate 12. The dielectric plate 12 is supported on the upper surface of the nozzle 21. The nozzle 21 is preferably made of a metal such as aluminum and has undergone an anodized surface treatment. Inside the nozzle 21, a gas flow path 21a is formed in the horizontal direction. In addition, the nozzle 21 has multiple gas release holes 21b that connect the gas flow path 21a and the lower surface (internal space 14a) of the nozzle 21.

[0043] A gas inlet pipe 22, which communicates with the gas flow path 21a, is connected to the upper surface of the nozzle 21. The gas inlet pipe 22 extends upward through the upper chamber 13 and is connected to the gas supply section 23 located outside the processing container 10.

[0044] The gas supply unit 23 has a gas supply pipe 24 connected to the gas inlet pipe 22, and a gas supply source 25, a mass flow controller 26, and an on / off valve 27 are sequentially arranged from upstream to downstream of the gas supply pipe 24. During the film formation process, 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. The gas flows from the gas supply pipe 24 into the gas flow path 21a through the gas inlet pipe 22, and is released into the internal space 14a through each gas release hole 21b.

[0045] A high-frequency antenna 28 is disposed within the upper chamber 13 that forms the antenna chamber 13a. The high-frequency antenna 28 is formed by wiring an antenna made of a conductive metal such as copper in a loop or spiral pattern. Alternatively, multiple loop antennas may be disposed within the high-frequency antenna 28. A power supply component 29 extending upward within the upper chamber 13 is connected to the terminals of the high-frequency antenna 28.

[0046] The power supply component 29 has an upper end protruding outward from the processing container 10, to which a power supply line 30 is connected. The power supply line 30 is connected to a high-frequency power supply 32 via an impedance matching device 31. The high-frequency power supply 32 applies high-frequency power (e.g., 13.56 MHz) to the high-frequency antenna 28 at a frequency corresponding to the substrate processing. As a result, the high-frequency antenna 28 generates an induced electric field within the lower chamber 14.

[0047] Furthermore, the processing container 10 has a mounting stage 40 (worktable) within the lower chamber 14 for placing the substrate G fed in from the feed inlet 17. The mounting stage 40 has a mounting stage body 41, a base 42, a plurality of lifting pins 43, and a plurality of lifting pin lifting mechanisms 44. The substrate G fed into the lower chamber 14 is handed over to the lifting pins 43 raised by the lifting pin lifting mechanisms 44, and then the lifting pins 43 are lowered, thereby placing it onto the mounting stage body 41.

[0048] The mounting stage body 41 is rectangular in shape when viewed from above, and has a mounting surface 411 with the same planar dimensions as the substrate G. For example, the planar dimensions of the mounting surface 411 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.

[0049] A plasma processing space PCS is formed between the mounting surface 411 of the stage body 41 and the nozzle 21. In the plasma processing space PCS, plasma is generated by the induced electric field formed by the high-frequency antenna 28, which plasmaifies the gas supplied from the nozzle 21 to the internal space 14a. The plasma processing apparatus 1 provides the film-forming precursor in the plasma generated in the plasma processing space PCS to the substrate G.

[0050] Furthermore, the stage body 41 is formed of aluminum, aluminum alloy, or the like, and has a heating wire 45 inside, which acts as a resistive element. The heating wire 45 is connected to the heating drive unit 46 and is heated based on the power supply from the heating drive unit 46. The heating drive unit 46 is connected to the control unit 60 of the plasma processing apparatus 1 and outputs power corresponding to the temperature command of the control unit 60. Moreover, the stage body 41 may also have a cooling mechanism for precise temperature control. For example, when performing substrate processing (film formation), the plasma processing apparatus 1 heats the mounting surface 411 of the stage 40 to about 200°C and maintains that temperature.

[0051] The base 42, made of insulating material, is disposed on the bottom plate 33 of the lower chamber 14 and supports the platform body 41. The base 42 has an opening at the bottom, which fixes and supports the platform body 41 when it is separated from the bottom plate 33.

[0052] The plasma processing apparatus 1 includes a control unit 60 that controls the operation of the entire apparatus. The control unit 60 is a control computer having one or more processors 61, a memory 62, an input / output interface (not shown), and electronic circuitry. The memory 62 includes non-volatile memory and volatile memory, forming a storage unit for the control unit 60 that stores program and process data. Furthermore, a portion of the memory 62 may be integrated into the processor 61. The input / output interface is connected to an input / output device (not shown) of the plasma processing apparatus 1. Examples of input / output devices include touch panels, monitors, and keyboards. The one or more processors 61 may be one or a combination of processors such as CPUs, ASICs, FPGAs, or circuits composed of multiple discrete semiconductors. The one or more processors 61 execute the program in the memory 62 and perform plasma processing on the substrate G according to the process data.

[0053] Furthermore, the plasma processing apparatus 1 has an exhaust port 14b on the bottom plate 33 of the processing container 10 for venting gas from the internal space 14a, and an exhaust section 70 connected to the processing container 10 via the exhaust port 14b. Additionally, in Figure 1 The example shown is one exhaust port 14b and one exhaust section 70, but the plasma processing apparatus 1 may also have multiple exhaust ports 14b and exhaust sections 70.

[0054] The exhaust port 14b is formed into a perfect circle and is disposed between the side wall of the processing container 10 and the mounting stage 40. The diameter of the exhaust port 14b also depends on the size of the processing container 10, and is preferably set in the range of about 200mm to 400mm, and is set to 300mm in this embodiment. In addition, the shape of the exhaust port 14b may not be a perfect circle, but may be a semi-circle or other shape corresponding to the placement position, depending on the placement position.

[0055] Figure 2 This is an enlarged cross-sectional schematic diagram showing the exhaust port 14b (gas exhaust port) from which gas is discharged from the processing container 10. (See diagram below.) Figure 2 As shown, the exhaust section 70 includes an exhaust pipe 71 connected to the exhaust port 14b and an exhaust mechanism 72 provided on the exhaust pipe 71 for exhausting the gas (e.g., volatile gas) inside the processing container 10.

[0056] The exhaust pipe 71 is a pipe with a circular cross-section and an inner passage 71a communicating with the exhaust port 14b, and is formed of a suitable metal. The exhaust pipe 71 can be as follows: Figure 2It extends downwards in a straight line as shown, but it can also be curved or bent midway. Additionally, as described above, by grounding the processing container 10, the exhaust pipe 71 connected to the processing container 10 is also grounded. Preferably, a coating for inhibiting corrosion of the exhaust pipe 71 is applied to the inner circumferential surface of the exhaust pipe 71 constituting the passage 71a.

[0057] like Figure 1 and Figure 2 As shown, the exhaust mechanism 72, downstream of the gas flow direction from the exhaust pipe 71, includes an APC (Automatic Pressure Control) valve 73, a turbomolecular pump (TMP) 74, and a dry pump 75. After coarsely evacuating the processing container 10 using the dry pump 75, the exhaust mechanism 72 uses the turbomolecular pump 74 to evacuate the processing container 10. Furthermore, the exhaust mechanism 72 controls the pressure in the internal space 14a by adjusting the opening of the APC valve 73.

[0058] The exhaust screen 100 is disposed in contact with the exhaust pipe 71 or the lower chamber 14 between the inlet side of the APC valve 73 of the exhaust mechanism 72, which extends from the stage 40 (stage) through the exhaust port 14b to the exhaust pipe 71 in the plasma processing apparatus 1. The exhaust screen 100 becomes grounded by contacting the exhaust pipe 71 or the lower chamber 14, which is a grounded potential. Therefore, the exhaust screen 100 can shield the plasma, suppressing plasma intrusion into the APC valve 73, turbomolecular pump 74, etc. More preferably, the exhaust screen 100 is disposed with a portion of its part in contact with the lower chamber 14 at a position closer to the exhaust port 14b than the inlet side of the APC valve 73, or near the exhaust port 14b (outlet side, inlet side). By being disposed near the exhaust port 14b, the exhaust screen 100 can prevent discharge caused by plasma intrusion into the exhaust pipe 71. Furthermore, the exhaust screen 100 can prevent components from falling into the APC valve 73 inside the exhaust pipe 71.

[0059] In this embodiment, the plasma processing apparatus 1 has an exhaust screen 100 disposed at the connection end of the exhaust port 14b in the exhaust pipe 71, adjacent to the outlet side of the exhaust port 14b. Alternatively, the exhaust screen 100 may be disposed at the inlet side of the exhaust port 14b. Furthermore, the exhaust screen 100 may be disposed at the inlet side of the exhaust port 14b in contact with the lower chamber 14, or it may be disposed within the exhaust port 14b (between the outlet side and the inlet side) in contact with the lower chamber 14. Alternatively, the exhaust screen 100 may be disposed in direct or indirect electrical contact with the lower chamber 14 in the internal space 14a above the exhaust port 14b. In addition to having an exhaust screen 100 in the exhaust pipe 71 (or exhaust port 14b), the plasma processing apparatus 1 may also have a baffle (not shown) inside the processing container 10. Furthermore, when the exhaust screen 100 is not in electrical contact with the lower chamber 14 and is not in contact with the exhaust pipe 71 and therefore does not become grounded, the effect of the exhaust screen 100 in shielding the plasma will be weakened.

[0060] Figure 3 This is a three-dimensional diagram representing the exhaust screen 100. (Example:) Figure 3 As shown, the exhaust screen 100 is circular when viewed from above. The diameter of the exhaust screen 100 is preferably set in the range of approximately 200 mm to 400 mm. In this embodiment, an exhaust screen 100 with a diameter of 300 mm is used, depending on the size of the exhaust port 14b.

[0061] like Figure 2 and Figure 3 As shown, the exhaust mesh 100 has an annular outer frame portion 101 and an inner portion 102 that allows gas to flow inside the outer frame portion 101. Alternatively, the exhaust mesh 100 can be constructed using only the inner portion 102, which has a honeycomb structure 104, without the outer frame portion 101. Furthermore, the exhaust pipe 71 and the exhaust mesh 100 are secured to the exhaust pipe 71 in a detachable manner via a snap-fit ​​mechanism 76.

[0062] For example, a snap-fit ​​mechanism 76 is provided at the connection end (upper end) of the exhaust pipe 71 connected to the processing container 10. The inner diameter of the exhaust pipe 71 is set to be approximately the same as the diameter of the inner side portion 102, and the connection end of the exhaust pipe 71 has a flange portion 77 that extends radially outward corresponding to the outer frame portion 101. With the outer frame portion 101 of the exhaust mesh 100 mounted on the flange portion 77, the exhaust pipe 71 is fixed to the bottom plate 33 of the processing container 10 by a connecting mechanism such as screws. Thus, the plasma processing apparatus 1 can be arranged with the exhaust mesh 100 adjacent to the exhaust port 14b of the processing container 10 along with the connection of the exhaust pipe 71. In addition, the inner side portion 102 is arranged opposite to the passage 71a inside the exhaust pipe 71 when the exhaust pipe 71 is arranged.

[0063] The outer frame 101 and the inner side 102 are continuous with each other by a metal mainly composed of stainless steel (e.g., SUS304) or aluminum. Alternatively, the exhaust mesh 100 may be coated with a ceramic such as yttrium oxide (Y2O3). Through the ceramic coating, the exhaust mesh 100 can possess plasma resistance. However, the ceramic coating needs to be of sufficient thickness to allow the exhaust mesh 100 to function as a ground potential in the RF circuit. The exhaust mesh 100, formed of metal and fixed to the exhaust pipe 71, is grounded (connected to the ground potential) via the exhaust pipe 71 and the processing container 10.

[0064] Figure 4 This is an enlarged illustration of the honeycomb structure 104 of the exhaust mesh 100. Figure 4 (a) is a partial top view of the inner side 102 of the exhaust mesh 100. Figure 4 (b) is a partial cross-sectional view along line IV-IV of (a). The inner portion 102 of the exhaust mesh 100 is formed as a plate, and a honeycomb structure 104 is formed by arranging multiple hexagonal (regular hexagonal) through holes 103 that share common sides and are adjacent to each other. That is, as shown Figure 4 As shown in (a), the inner portion 102 has a plurality of through holes 103 and a plurality of hole edges 105 that respectively surround each of the plurality of through holes 103. In addition, each through hole 103 may also be a hexagonal shape other than a regular hexagonal shape (e.g., a flat hexagonal shape).

[0065] The through holes 103 of the honeycomb structure 104 are arranged in a direction parallel to each other along the edges 105 (orthogonal to the length direction of the edges 105), forming the mesh (grid) of the exhaust net 100. Each edge 105 is elongated compared to the size of each through hole 103 and extends linearly with a certain width. Furthermore, each edge 105 and each hexagonal through hole 103 are correspondingly formed to have the same length and are connected to each other at an angle of 120°. By having such a plurality of through holes 103 and edges 105, the opening ratio of the inner portion 102 (exhaust net 100) is set to 85% or more. That is, through the honeycomb structure 104, the opening ratio of the inner portion 102 of the exhaust net 100 is significantly increased, allowing gas to easily flow from the exhaust port 14b to the passage 71a.

[0066] In addition, such as Figure 4 As shown in (b), the exhaust mesh 100 is formed by stacking multiple thin plates (hereinafter referred to as thin plate honeycomb mesh 110) having a honeycomb structure 104 on each other and joining the multiple thin plate honeycomb meshes 110 together by the manufacturing method described later. Therefore, the exhaust mesh 100 has a structure (joint portion 106) formed by joining the multiple thin plate honeycomb meshes 110 in the thickness direction.

[0067] The joint 106 is formed by a suitable joining means in the manufacturing process. For example, the joint 106 is formed by diffusion bonding, such that atoms of the lower thin-plate honeycomb network 110 and the upper thin-plate honeycomb network 110 diffuse into each other at their interface and reform grains across the interface. In addition, the joint 106 is not limited to diffusion bonding. As long as the bonding can maintain the electrical conductivity between the lower thin-plate honeycomb network 110 and the upper thin-plate honeycomb network 110, the lower thin-plate honeycomb network 110 and the upper thin-plate honeycomb network 110 can also be bonded by bonding means such as adhesive bonding, welding, or pressing.

[0068] The thickness ts (thickness in the thickness direction) of the thin-plate honeycomb mesh 110 is preferably set according to the width We (the interval between two adjacent through holes 103) of the hole edge 105, as described later. For example, it can be the same as or slightly shorter than the width We of the hole edge 105. In this embodiment, the thickness ts of the thin-plate honeycomb mesh 110 is set to 0.4 mm.

[0069] Furthermore, the width We of the plurality of aperture edges 105 is preferably set to a skin depth δ or greater than that of the following formula (1), using a high-frequency f, a relative permeability μr, a vacuum permeability μ0, and a conductivity σ. This is to facilitate the flow of high-frequency electricity along the inner wall surface of the through hole 103 formed by the aperture edges 105.

[0070] δ=1 / (π×f×μr×μ0×σ) 1 / 2 …(1)

[0071] As an example, assuming SUS304 is used as the material for the thin-plate honeycomb mesh 110 and the high-frequency power output is 3.2MHz, the skin depth δ of equation (1) is 0.27mm. Therefore, the width We of the hole edge 105 (the spacing between the through holes 103) is 0.3mm or more. As a result, the high-frequency power can easily flow on the inner wall surface of the through holes 103 of the exhaust mesh 100 formed by joining the thin-plate honeycomb mesh 110, and can flow to the ground through the exhaust mesh 100. As a result, abnormal discharge in the exhaust mesh 100 can be avoided. For example, the width We of the hole edge 105 can also be set in the range of about 0.3mm to 1.0mm. However, if the width We of the hole edge 105 is increased, the aperture ratio decreases, the conductivity decreases, and the gas exhaust efficiency deteriorates. Therefore, the width We of the hole edge 105 is preferably 0.4mm or less. As described above, in order to balance exhaust performance and discharge stability, it is more preferable to set the spacing between the through holes 103 of the thin plate honeycomb mesh 110 in the range of 0.3 mm to 0.4 mm.

[0072] In this embodiment, the width We of the hole edge 105 is set to 0.4 mm. That is, the hole edge 105 of the thin plate honeycomb mesh 110 has a roughly square shape with a thickness ts of 0.4 mm and a width We of 0.4 mm in a cross section orthogonal to the extending direction of the hole edge 105.

[0073] Furthermore, the number of layers of the thin-plate honeycomb mesh 110 constituting the exhaust mesh 100 can be arbitrarily designed, preferably in the range of about 2 to 15 layers, and in this embodiment, it is set to 10 layers. That is, the overall thickness T of the exhaust mesh 100 formed by stacking multiple thin-plate honeycomb meshes 110 is preferably set to the range of about 0.8 mm to 6.0 mm, and in this embodiment, it is 4.0 mm. By making the thickness T of the exhaust mesh 100 0.8 mm or more, plasma intrusion into the APC valve 73 side can be suppressed.

[0074] To suppress the intrusion of plasma generated by high-frequency electricity in the processing container 10, the size of each through-hole 103 of the exhaust mesh 100 is set such that the length E of the line connecting the two opposite vertices of the hexagonal shape of each through-hole 103 is shorter than the wavelength of the high frequency. Furthermore, to prevent components used in the processing container 10 (e.g., M4 screws) from falling out, each through-hole 103 is preferably set to a size smaller than the component. As an example, the distance D (width of the through-hole 103) between a pair of parallel hole edges 105 sandwiching each through-hole 103 can be set in the range of approximately 3.0 mm to 7.0 mm; in this embodiment, it is set to 4.77 mm (=3 / 16 inch).

[0075] Furthermore, when the spacing D between the hole edges 105 is 4.77 mm, the discharge becomes unstable when the thickness T of the exhaust mesh 100 is 2.0 mm, and the exhaust characteristics deteriorate when the thickness T is 4.0 mm. Therefore, the width of the through hole 103 (the spacing D between a pair of hole edges 105) is preferably in the range of 1.4 to 2.0 times the thickness T of the exhaust mesh 100. When the width of the through hole 103 is less than 1.4 times the thickness T of the exhaust mesh 100, the aperture ratio decreases and the possibility of gas flow difficulties increases. On the other hand, when the width of the through hole 103 is greater than 2.0 times the thickness T of the exhaust mesh 100, although the aperture ratio increases, plasma can easily pass through the exhaust mesh 100, causing abnormal discharge.

[0076] Furthermore, the ratio of the width We of the hole edge 105 to the width of the through hole 103 (the distance D between a pair of hole edges 105) is preferably in the range of about 1 / 15 to 1 / 8. When this ratio is less than 1 / 15, the discharge stability and mechanical strength of the plasma of the exhaust network 100 decrease, and when this ratio is greater than 1 / 8, there is a possibility of a decrease in the opening ratio.

[0077] Figure 5 This is a step-by-step diagram illustrating the manufacturing method of the exhaust screen 100. Next, refer to... Figure 5 The manufacturing method of the exhaust screen 100 described above will be explained.

[0078] In the manufacturing of the exhaust mesh 100, the manufacturer sequentially performs the preparation step, the plate processing step, and the joining step.

[0079] The preparation step involves preparing multiple metal plates 120 to serve as the substrate for the thin-film honeycomb mesh 110. The manufacturer prepares these multiple metal plates 120 through forming, purchasing, or other methods. In this embodiment, the multiple metal plates 120 are stainless steel (SUS) plates having the same thickness ts as the intended thickness of the thin-film honeycomb mesh 110. During the preparation step, plates with a thickness different from the intended thickness ts of the thin-film honeycomb mesh 110 may also be appropriately processed (e.g., stamped) to obtain the target thickness ts.

[0080] The plate processing step is a step of creating a thin plate honeycomb mesh 110 with a honeycomb structure 104 by forming a plurality of through holes 103 on the metal plate 120. For example, in the plate processing step, the plurality of metal plates 120 are etched separately.

[0081] As an apparatus for etching the metal plate 120, an etching apparatus (not shown) that performs wet etching can be cited as an example. In this case, the manufacturer inputs a processing plan for a honeycomb structure 104 having multiple through holes 103 into the etching apparatus, and places the metal plate 120 in the etching apparatus. A mask for each hole edge 105 of the honeycomb structure 104 is formed on the metal plate 120 beforehand, and then the metal plate 120 is immersed in the etching solution of the etching apparatus, thereby forming through holes 103 at the locations exposed from the mask. Burrs may sometimes be generated during machining processes such as punching, but by performing etching in the plate processing step as described above, the generation of machining marks such as burrs on the metal plate 120 can be suppressed. In addition, in the plate processing step, not limited to etching, multiple through holes 103 can be formed on each metal plate 120 by other processing methods that do not generate burrs. In addition, the outer periphery shape of the thin plate honeycomb mesh 110 can be formed at the same time as the through hole 103 is formed by the above wet etching. Alternatively, the metal plate 120 can be pre-processed into the outer periphery shape of the thin plate honeycomb mesh 110 before forming the through hole 103.

[0082] The joining step is a step of creating a thick plate exhaust mesh 100 by stacking multiple thin-plate honeycomb meshes 110 formed in the plate processing step and joining them together. At this time, the manufacturer positions the thin-plate honeycomb meshes 110 to each other so that the through holes 103 of the multiple thin-plate honeycomb meshes 110 are interconnected, and then stacks the thin-plate honeycomb meshes 110. For example, at the location where the multiple thin-plate honeycomb meshes 110 are stacked (e.g., at the worktable of the joining operation), several pins (not shown) slightly smaller than the hexagonal through holes 103 are erected, and by inserting these pins into the respective through holes 103, the thin-plate honeycomb meshes 110 can be positioned relative to each other.

[0083] Alternatively, as a method for joining multiple thin-plate honeycomb meshes 110 together, diffusion bonding (including vacuum diffusion bonding or argon diffusion bonding) can be employed. In this case, the manufacturer uses a diffusion bonding apparatus (not shown) to pressurize and heat (hot press) the stacked multiple thin-plate honeycomb meshes 110. As a result, the metal atoms at the interfaces between the stacked thin-plate honeycomb meshes 110 diffuse and mix with each other, causing the voids to disappear, crossing the interfaces, and reforming the metal atom grains (bonding portions 106), thus bonding the thin-plate honeycomb meshes 110 together.

[0084] The exhaust mesh 100 manufactured by the above method becomes a thick plate of clean honeycomb structure 104 without burrs and / or step differences. That is, after the plate processing and joining steps, each through hole 103 of the exhaust mesh 100 is smoothly continuous along the thickness direction of the exhaust mesh 100 (the stacking direction of the multiple thin plate honeycomb meshes 110), maintaining a high opening ratio of the multiple thin plate honeycomb meshes 110. Therefore, the exhaust mesh 100 can allow gas to pass through stably in the thickness direction and can suppress abnormal plasma discharge with an appropriate thickness T.

[0085] Figure 6 This is an explanatory diagram showing the experimental results confirming the exhaust performance of the exhaust mesh. Figure 6 (a) is a graph showing the exhaust performance of the exhaust network when the pressure inside the processing container 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 oxygen supply flow rate [slm] supplied to the processing container 10 by the mass flow controller 26. That is, during the process of adjusting the pressure inside the processing container 10 to 10 mT, the change in the gas supply flow rate to the processing container 10 is equivalent to the exhaust volume of the gas discharged from the processing container 10 to the exhaust section 70.

[0086] In addition, Figure 6In graph (a), the flow rate change is represented by a solid line when an exhaust screen 100 (hereinafter referred to as honeycomb exhaust screen A) with the honeycomb structure 104 of this embodiment is applied. The flow rate change is represented by a dashed line when an exhaust screen with a plurality of circular holes 130 of the prior art and a comparative example (hereinafter referred to as circular hole exhaust screen B) is applied. Figure 6 (b) is an enlarged top view of the honeycomb exhaust net A used in the illustrative experiment. Figure 6 (c) is an enlarged top view of the circular perforated exhaust screen B used in the illustrative experiment.

[0087] The size of each through hole 103 in the honeycomb exhaust mesh A (the spacing D between a pair of hole edges 105) is 4.77 mm as described above, resulting in an overall opening ratio of 85.1% for the honeycomb exhaust mesh A. In contrast, the diameter of each circular hole 130 in the circular hole exhaust mesh B is 5 mm, but the overall opening ratio of the circular hole exhaust mesh B is 62.9%. Both the honeycomb exhaust mesh A and the circular hole exhaust mesh B have an outer diameter of 350 mm. The thickness of the honeycomb exhaust mesh A is 3 mm, and the thickness of the circular hole exhaust mesh B is 2 mm.

[0088] like Figure 6 As shown in (a), in both the honeycomb exhaust net A and the perforated exhaust net B, the gas supply flow rate to the processing container 10 increases with the increase of the opening degree of the APC valve 73. That is, the pressure inside the processing container 10 is constant, so the increase in the gas supply flow rate means an increase in the exhaust volume. However, the larger the opening degree of the APC valve 73, the greater the increase in the gas supply flow rate of the honeycomb exhaust net A compared to the perforated exhaust net B. For example, when the opening degree of the APC valve 73 is 400, the supply flow rate of the perforated exhaust net B is 4.55 [slm], while the supply flow rate of the honeycomb exhaust net A is 4.8 [slm]. That is, the honeycomb exhaust net A discharges more gas from the processing container 10 to the exhaust section 70 than the perforated exhaust net B, so it can be said that the exhaust performance of the honeycomb exhaust net A is better than that of the perforated exhaust net B. Furthermore, while there were aspects in the experiment where simple comparisons were impossible due to manufacturing limitations of each exhaust mesh, the following conclusions were drawn from studying the configurations of the hexagonal through holes 103 and the circular holes 130: With the hexagonal through holes 103, if the distance between the through holes 103 is close to zero, the opening ratio approaches 100%. On the other hand, with the circular holes 130, even if the distance between the circular holes 130 is close to zero, there are still gaps between the openings of the three circular holes 130, with an opening ratio of approximately 93% as the limit. Therefore, it can be concluded that the opening ratio of the honeycomb exhaust mesh A is superior to that of the circular hole exhaust mesh B.

[0089] Figure 7 This is a table showing the discharge stability in response to changes in pressure within the processing container 10 and changes in plasma output. Additionally, Figure 7 (a) is the case where an exhaust net 100 (honeycomb exhaust net A) with the honeycomb structure 104 of this embodiment is applied. Figure 7 (b) describes the application of an exhaust mesh (orifice exhaust mesh B) with multiple circular holes 130 as in the comparative example. Discharge stability is determined by visually observing the occurrence of abnormal discharges in the multiple through holes 103 or multiple circular holes 130. Specifically, if plasma-generated light does not occur in any of the through holes 103 or circular holes 130, discharge stability is determined and recorded as OK. If plasma-generated light occurs in any of the through holes 103 or circular holes 130, discharge stability is determined and recorded as NG.

[0090] like Figure 7 As shown in (b), the circular aperture exhaust net B exhibits discharge stability when the pressure of the processing container 10 is below 15 mT (2.00 Pa). However, when the pressure of the processing container 10 is 20 mT (2.67 Pa) and the plasma output (high-frequency power) is 11.1 kW or more, the circular aperture exhaust net B lacks discharge stability. Furthermore, when the pressure of the processing container 10 is between 25 mT (3.33 Pa) and 35 mT (4.67 Pa), the circular aperture exhaust net B generates abnormal discharges with a plasma output of 5.5 kW or more. Moreover, when the pressure of the processing container 10 is 40 mT (5.33 Pa), the discharge stability of the circular aperture exhaust net B disappears regardless of the plasma output.

[0091] Unlike this, such as Figure 7 As shown in (a), the cellular exhaust network A does not generate abnormal discharge when the pressure of the processing container 10 is below 20 mT (2.67 Pa). Furthermore, the cellular exhaust network A lacks discharge stability when the pressure of the processing container 10 is 25 mT (3.33 Pa) and the plasma output (high-frequency power) is 18.0 kW or more. Additionally, the cellular exhaust network A lacks discharge stability when the pressure of the processing container 10 is 30 mT (4.00 Pa) and the plasma output is 8.3 kW or more. Moreover, when the pressure of the processing container 10 is between 35 mT (4.67 Pa) and 40 mT (5.33 Pa), the cellular exhaust network A lacks discharge stability if the plasma output is 5.5 kW or more. Therefore, the cellular exhaust network A achieves discharge stability even at a low plasma output when the pressure of the processing container 10 is 40 mT (5.33 Pa).

[0092] from Figure 7 (a) and Figure 7As shown in (b), honeycomb exhaust mesh A is easier to achieve discharge stability and the discharge stability region is larger compared to circular hole exhaust mesh B. That is, from the point of view of discharge stability, honeycomb exhaust mesh A can be said to be superior to circular hole exhaust mesh B.

[0093] As described above, the method for manufacturing an exhaust mesh 100 according to one aspect of the present invention can form a honeycomb structure 104 with a plurality of hexagonal through holes 103 arranged with high precision. Furthermore, the opening ratio of the exhaust mesh 100 is significantly increased due to the honeycomb structure 104, thus improving the exhaust performance when exhausting gas. In addition, in the method for manufacturing the exhaust mesh 100, a plurality of thin-plate honeycomb meshes 110 are joined together to form a thick plate. As a result, the exhaust mesh 100 reduces abnormal plasma discharge and further improves discharge stability. In other words, the exhaust mesh 100 can improve both exhaust performance and discharge stability.

[0094] Furthermore, the opening ratio of the honeycomb structure 104 in the exhaust mesh 100 is over 85%. Therefore, the exhaust mesh 100 can further improve exhaust performance.

[0095] Furthermore, the spacing between adjacent through holes 103 is in the range of 0.3 mm to 0.4 mm. As a result, in the exhaust mesh 100, the width We of the hole edges 105 extending between the multiple through holes 103 becomes narrower, making it easier to increase the opening ratio.

[0096] Furthermore, the spacing D between a pair of hole edges 105 extending parallel to each other with multiple through holes 103 is in the range of 1.4 to 2.0 times the thickness T of the exhaust mesh 100. Thus, the exhaust mesh 100 improves exhaust performance by increasing the size of the multiple through holes 103, and by fully utilizing the length of the through holes 103 along the thickness direction, it can improve discharge stability.

[0097] Furthermore, in the bonding step, multiple thin-plate honeycomb meshes 110 are bonded together by diffusion bonding. Thus, the method for manufacturing the exhaust mesh 100 can firmly fix multiple thin-plate honeycomb meshes 110 together and can stably produce an exhaust mesh 100 that suppresses burrs and staggered edges.

[0098] Furthermore, in the plate processing step, multiple through holes 103 are formed by wet etching multiple metal plates 120 through multiple honeycomb-shaped masks. Thus, the method for manufacturing the exhaust mesh 100 can efficiently and precisely form a thin-plate honeycomb mesh 110.

[0099] Furthermore, one embodiment of the plasma processing apparatus 1 for plasma processing of a substrate G according to the present invention includes: a processing container 10 having a mounting stage (mounting stage 40) for placing the substrate G; an exhaust pipe 71 connected to an exhaust port 14b provided in the processing container 10; an exhaust mechanism 72 provided in the exhaust pipe 71 for exhausting gas within the processing container 10; and an exhaust mesh 100 provided at a position between the mounting stage 40, the exhaust port 14b, and the exhaust mechanism 72 in the exhaust pipe 71. The exhaust mesh 100 has a honeycomb structure 104 formed by adjacently arranged hexagonal through holes 103, and is formed as a thick plate by having a structure in which multiple thin-plate honeycomb meshes 110 are joined in the thickness direction. Thus, the plasma processing apparatus 1 can improve exhaust performance and discharge stability.

[0100] Furthermore, the exhaust mesh 100 has a structure in which multiple thin-plate honeycomb meshes 110 are joined together by diffusion bonding. As a result, the exhaust mesh 100 with the joint portion 106 can be formed into a thick plate while suppressing burrs and step differences, thereby improving exhaust performance and discharge stability.

[0101] Furthermore, the exhaust net 100 is positioned such that it can cover the exhaust port 14b. By covering the exhaust port 14b with the exhaust net 100, the plasma processing apparatus 1 can effectively suppress the intrusion of plasma into the exhaust pipe 71 connected to the downstream side of the exhaust net 100.

[0102] In another embodiment of the present invention, the exhaust screen is an exhaust screen 100 disposed in a plasma processing apparatus 1 for plasma processing of a substrate G. It has a honeycomb structure 104 formed by adjacent arrangement of a plurality of hexagonal through holes 103, and is formed as a thick plate by having a structure in which a plurality of thin-plate honeycomb meshes 110 are joined together in the thickness direction. Thus, the exhaust screen 100 can improve the exhaust performance and discharge stability of the plasma processing apparatus 1.

[0103] Furthermore, the exhaust mesh 100 has a structure in which multiple thin-plate honeycomb meshes 110 are joined together by diffusion bonding. Thus, the exhaust mesh 100 is formed as a thick plate while suppressing burrs and step differences.

[0104] The manufacturing method of the exhaust screen 100, the plasma processing apparatus 1, and the exhaust screen 100 disclosed herein are illustrative and not limiting in all respects. The embodiments can be modified and improved in various ways without departing from the appended technical solutions and their spirit. The items described in the above embodiments can be adopted in other structures and combined without contradiction.

[0105] The plasma processing apparatus 1 of the present invention can also be applied to any type of apparatus in PE-ALD (Plasma Enhanced Atomic Layer Deposition), PE-CVD (Plasma Enhanced Chemical Vapor Deposition), and dry etching. Examples of substrates subjected to plasma processing in the plasma processing apparatus 1 include 1.5m × 1.85m substrates of G6 and other rectangular substrates of other sizes, but it is not limited to these; various components such as disk-shaped wafers can also be used.

Claims

1. A method for manufacturing an exhaust screen, wherein the exhaust screen is used to allow gas to pass through when gas is discharged from a processing container of a plasma processing apparatus, characterized in that, The exhaust screen is made of stainless steel and is grounded via at least one of the lower chamber of the processing container having an exhaust port and an exhaust pipe connected to the exhaust port. The method for manufacturing the exhaust mesh includes: Step a, prepare multiple metal plates; Step b, forming a honeycomb structure in each of the plurality of metal plates, consisting of a plurality of hexagonal through holes arranged adjacent to each other at intervals ranging from 0.3 mm to 0.4 mm, to obtain a plurality of thin-plate honeycomb meshes; and Step c involves stacking the plurality of thin-plate honeycomb meshes in such a way that the plurality of through holes of the plurality of thin-plate honeycomb meshes are interconnected, and joining the plurality of thin-plate honeycomb meshes together to form the exhaust mesh as a thick plate.

2. The method for manufacturing an exhaust screen as described in claim 1, characterized in that: The opening ratio of the honeycomb structure in the exhaust mesh is 85% or more.

3. The method for manufacturing an exhaust mesh as described in claim 1 or 2, characterized in that: The spacing between a pair of hole edges that extend in parallel with multiple through holes is in the range of 1.4 to 2.0 times the thickness of the exhaust mesh.

4. The method for manufacturing an exhaust mesh as described in claim 1 or 2, characterized in that: In step c, the plurality of thin-plate cell meshes are joined together by diffusion bonding.

5. The method for manufacturing an exhaust screen as described in claim 1 or 2, characterized in that: In step b, the plurality of through holes are formed by wet etching each of the plurality of metal plates through a plurality of honeycomb-shaped masks.

6. A plasma processing apparatus for plasma processing of a substrate, characterized in that, include: A processing container having a stage for placing the substrate; An exhaust pipe connected to the exhaust port of the processing container; An exhaust mechanism, which is disposed in the exhaust pipe, exhausts the gas in the processing container; and An exhaust screen is positioned between the exhaust mechanism and the platform, via the exhaust port, and the exhaust pipe. The exhaust mesh is made of stainless steel and is grounded via at least one of the lower chamber of the processing container having the exhaust port and the exhaust pipe connected to the exhaust port. The exhaust mesh has a honeycomb structure consisting of multiple hexagonal through holes arranged adjacent to each other at intervals ranging from 0.3 mm to 0.4 mm, and is formed into a thick plate by having a structure in which multiple thin-plate honeycomb meshes are joined together in the thickness direction.

7. The plasma processing apparatus as described in claim 6, characterized in that: The exhaust mesh has a structure in which the plurality of thin-plate honeycomb meshes are joined together by diffusion bonding.

8. The plasma processing apparatus as described in claim 6 or 7, characterized in that: The position of the exhaust mesh is set so that it can cover the exhaust port.

9. An exhaust screen disposed in a plasma processing apparatus having a processing container for plasma processing of a substrate, characterized in that: The exhaust screen is made of stainless steel and is grounded via at least one of the lower chamber of the processing container having an exhaust port and an exhaust pipe connected to the exhaust port. The exhaust mesh has a honeycomb structure consisting of multiple hexagonal through holes arranged adjacent to each other at intervals ranging from 0.3 mm to 0.4 mm, and is formed into a thick plate by having a structure in which multiple thin-plate honeycomb meshes are joined together in the thickness direction.

10. The exhaust screen as described in claim 9, characterized in that: The exhaust mesh has a structure in which the plurality of thin-plate honeycomb meshes are joined together by diffusion bonding.

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