Gas mass flow controller filtering structure and gas conveying pipeline system

Abstract

The utility model discloses a gas mass flow controller filtering structure, and relates to the technical field of semiconductor production and manufacturing, a gas flow channel arranged in a gas path structural member is used for guiding gas to flow, a first step groove is formed in the inlet end of the gas flow channel, and the diameter of the first step groove is larger than that of the gas flow channel; a first step surface is formed at the junction of the first step groove and the airflow channel, the filter screen is welded and fixed on the first step surface, and the periphery of the filter screen is supported by the first step surface; the diameter of the filter screen is larger than that of the airflow channel, so that the airflow channel is completely covered; due to the adoption of a welding fixing form, when air flow passes through, the filter screen and the air path structural member do not move relatively to generate friction to cause particles, and the filter screen can completely cover the air flow channel, so that the interception efficiency is high, and a high-cleanliness effect can be achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor production and manufacturing, in particular to a gas mass flow controller filtering structure and a gas delivery pipeline system. BACKGROUND

[0002] A gas mass flow controller is a metering and control instrument for gas flow, mainly used in industrial, scientific research, environmental protection monitoring and medical equipment fields. In the semiconductor field, accurate control of the flow and quality of various gases is a key factor to ensure the stability of the manufacturing process and product quality. As a high-precision and high-stability measuring device, the gas mass flow controller plays an indispensable role in the semiconductor manufacturing process.

[0003] In the application of the semiconductor field, the cleanliness requirement of the gas mass flow controller is very high, and a filter is usually added upstream of the gas mass flow controller, and a filtering structure is also added inside the gas mass flow controller to ensure the normal operation of the gas mass flow controller and the cleanliness of the high-purity delivery gas path.

[0004] The existing technical solution usually uses a stainless steel woven filter disc installed in a clamping groove for filtering the flow channel of the gas mass flow controller, which is generally installed at the upstream position or both upstream and downstream positions. The filter screen not only plays a cleaning and filtering role, but also has an effect of uniform flow of the gas path.

[0005] In combination Figure 10 As shown in the prior art gas mass flow controller filter screen installation structure, the fine metal filter screen 01 and the coarse metal filter screen 02 are sequentially deformed by extrusion and then installed in the corresponding installation slot of the gas path structure block 03, and the installation slot hole diameter is slightly larger than the diameter of the outlet hole diameter. In this way, the filter screen can be fixed by relying on the limiting effect of its own shape. Generally, the fine metal filter screen 01 is placed upstream of the gas flow, and the coarse metal filter screen 02 is placed downstream. The coarse metal filter screen 02 has better rigidity and can provide good support to prevent the center of the fine metal filter screen 01 from being depressed and falling off due to the impact of the gas flow when the gas path flow is too large.

[0006] The clamping groove installation may have a filtering blind area. When installing the filter screen, the filter screen is easily deformed due to extrusion during installation and assembly gap caused by the installation slot cooperation, resulting in insufficient coverage of the filter screen and a filtering blind area.

[0007] The clamping groove installation has the risk of gas path shaking. When installing the filter screen, the filter screen is easily deformed due to warping during installation, and the flow rate pattern of the flow channel area not covered after deformation is inconsistent with other areas, thereby causing gas path shaking.

[0008] The filter screen is installed in the card slot, and generally two sets of filter screens are needed, one coarse and one fine. The effect of equal flow is not as good as that of a single set of fine filter screen. The fine filter screen plays a role in filtering the smallest particles to ensure cleanliness, but the wire of the filter screen is usually thin and the overall thickness is relatively thin, and the rigidity is not enough to support its effective fixation in the card slot, so the fine filter screen is usually arranged upstream of the gas path, and the coarse filter screen is arranged downstream of the gas path. The coarse filter screen mainly plays a role in supporting the fine filter screen.

[0009] The installation structure of the card slot is not stable enough, especially under dynamic flow, which is particularly obvious. Once the metal filter screen pulsates with the change of flow, mechanical friction will be generated between the structure and the structure, which will cause particle cleanliness problems.

[0010] In combination Figure 11 As shown in the prior art, another way of the prior art is to use a metal wire sintering filter structure, which comprises a first gas path structure 01, a metal wire sintering filter screen 02, a sealing ring 03, and a second gas path structure 04. The first gas path structure 01 and the second gas path structure 04 cooperate to press the metal wire sintering filter screen 02, and the sealing ring 03 is also pressed between the first gas path structure 01 and the second gas path structure 04. This structure is usually rigid enough, but the card slot needs to be made detachable during installation. That is, the first gas path structure 01 and the second gas path structure 04 are fixed by screws, and the metal wire sintering filter screen 02 is clamped and fixed in the slot. Since the filter structure is formed by metal wire sintering, it cannot be excessively pressed, otherwise the wire will break and fall off, which will cause the risk of particle pollution.

[0011] The metal wire sintering filter structure has the risk of filter blind area. Due to the existence of assembly gap, the filter structure has a certain activity space inside, that is, there is a gap, and it is impossible to completely cover the filter area.

[0012] Under the disturbance of dynamic flow, pulsating mechanical friction is easy to occur, particles are easy to be generated, and the internal cleanliness of the gas mass flow controller is affected. Practical new type content

[0013] The application discloses a gas mass flow controller filter structure, which is used to solve the problem that the filter screen is easy to generate particle pollutants, and the specific scheme is as follows:

[0014] In a first aspect, the application provides a gas mass flow controller filter structure, which comprises a gas path structure and a filter screen. The gas path structure is provided with a gas flow channel, the entering end of the gas flow channel is provided with a first stepped groove, and the diameter of the first stepped groove is greater than that of the gas flow channel. The filter screen is welded and fixed on the first step surface at the junction of the first stepped groove and the gas flow channel, and the diameter of the filter screen is greater than that of the gas flow channel, so as to completely cover the gas flow channel.

[0015] The filter screen is welded and fixed with the air path structure, the filter screen is connected firmly and stably, the filter screen will not be impacted and rubbed with the air path structure to generate particles, the filter screen will not be excessively extruded to generate particles, and high cleanliness is maintained; and the periphery of the filter screen is welded and fixed, so that the filter screen can also avoid being bent and deformed due to air flow impact to affect air flow uniformity; the filter screen forms 100% complete coverage on the air flow passage area, eliminates the filtering blind area caused by assembly gap, and has high interception efficiency.

[0016] In a possible implementation, the circumferential edge of the filter screen is fully welded or uniformly point-welded. The filter screen can be selected to be fully welded or uniformly point-welded based on the flow and pressure of the flow-through, so as to reasonably control the welding cost.

[0017] In a possible implementation, the filter screen is fixed by laser protection welding or vacuum diffusion welding. Both laser protection welding and vacuum diffusion welding can maximize the guarantee of not introducing impurities while meeting the demand for welding strength.

[0018] In a possible implementation, the filter screen is a woven metal wire screen or is formed by punching on a flat plate.

[0019] In a possible implementation, the filter screen is provided with single-layer or multi-layer woven metal wire.

[0020] In a possible implementation, the filter screen is a flat screen. The flat screen is convenient to process and manufacture, and is helpful to reasonably control the cost.

[0021] In a possible implementation, the flow channel surface of the air flow passage is subjected to fluid polishing or electrolytic polishing treatment. The high smoothness surface after precision machining guarantees the cleanliness of the air flow passage, and facilitates more thorough cleaning of particles by blowing.

[0022] In a possible implementation, the first stepped groove is provided with a second stepped groove at an entering end, the diameter of the second stepped groove is greater than that of the first stepped groove, a second step surface is formed at the junction of the second stepped groove and the first stepped groove, and the second stepped groove is used for inserting and assembling the gas pipeline.

[0023] In a second aspect, the application provides a gas delivery pipeline system, which comprises a filter, a diaphragm valve and a gas mass flow controller, and the gas mass flow controller adopts the gas mass flow controller filtering structure according to any one of the above. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0025] Figure 1 The axial view of the filter structure of the gas mass flow controller according to the embodiment of the present application;

[0026] Figure 2 The cross-sectional axial view of the filter structure of the gas mass flow controller according to the embodiment of the present application from one perspective;

[0027] Figure 3 The cross-sectional axial view of the filter structure of the gas mass flow controller according to the embodiment of the present application from another perspective;

[0028] Figure 4 The cross-sectional view of the filter structure of the gas mass flow controller according to the embodiment of the present application;

[0029] Figure 5 The first welding schematic view of the front view structure of the filter structure of the gas mass flow controller according to the embodiment of the present application;

[0030] Figure 6 The second welding schematic view of the front view structure of the filter structure of the gas mass flow controller according to the embodiment of the present application;

[0031] Figure 7 The axial view of the gas path structure according to the embodiment of the present application;

[0032] Figure 8 The cross-sectional axial view of the gas path structure according to the embodiment of the present application;

[0033] Figure 9 The schematic view of the gas delivery pipeline system according to the embodiment of the present application;

[0034] Figure 10 The filter screen mounting structure of the first gas mass flow controller according to the prior art;

[0035] Figure 11 The filter screen mounting structure of the second gas mass flow controller according to the prior art.

[0036] Explanation of reference signs:

[0037] 10-gas path structure; 101-gas flow channel; 1011-horizontal air duct; 1012-vertical air duct; 102-first stepped groove; 1021-first stepped surface; 103-second stepped groove; 1031-second stepped surface; 20-filter screen; 30-welding seam. DETAILED DESCRIPTION

[0038] In the process of semiconductor product processing, various gases need to be applied, and the gas mass flow controller can accurately control the flow of various gases to ensure the stability of the semiconductor production process. The filter screen in the gas mass flow controller is not stable enough due to the insufficient installation form, and the metal filter screen generates particles due to the pulsation of the flow change or the excessive extrusion of the filter screen, which affects the cleanliness of the gas.

[0039] The application provides a gas mass flow controller filtering structure applied to a gas mass flow controller, which filters the passing airflow and makes the passing airflow uniformly distributed; the filter screen structure is firmly connected and neither pulsation of the filter screen nor excessive extrusion of the filter screen occurs, and no relative movement occurs between the filter screen and the gas path structural member when the airflow passes, so as to generate particles due to friction, thereby improving the cleanliness; the filter screen completely covers the airflow channel, thereby reducing the blind area of filtration.

[0040] In order to enable those skilled in the art to better understand the technical solutions of the present application, the semiconductor shower head of the present application will be described in detail below in combination with the accompanying drawings and specific embodiments. The terms used in the following embodiments are only for the purpose of describing the specific embodiments and are not intended to be limiting to the present application. As used in the specification and the appended claims of the present application, the singular expressions "one", "a", "some", "the above", "the" and "this" are intended to also include expressions such as "one or more", unless there is clear indication to the contrary in the context. The directional expressions described below are described in the direction corresponding to the direction shown in the accompanying drawings, and do not represent the direction in the actual use state.

[0041] Embodiment one:

[0042] The gas mass flow controller filtering structure of the present application is suitable for a gas mass flow controller, which comprises a gas path structural member 10 and a filter screen 20. The gas path structural member 10 is a block-shaped solid structure, which can adopt a cuboid, a cylinder or the like. The gas path structural member 10 is provided with an airflow channel 101, which is a cavity provided inside the gas path structural member 10. As shown in Figure 4 In some embodiments, the airflow channel 101 comprises a horizontal air duct 1011 and a vertical air duct 1012, which are in communication with each other, and the extension directions of the horizontal air duct 1011 and the vertical air duct 1012 are perpendicular to each other, and the gas flows from the horizontal air duct 1011 to the vertical air duct 1012 to change the direction. The inner diameters of the horizontal air duct 1011 and the vertical air duct 1012 are not required to be equal, and the inner diameter of the horizontal air duct 1011 is usually greater than that of the vertical air duct 1012. As shown in Figure 4As shown by the arrow, the right end of the horizontal air passage 1011 is the inlet end for the gas to enter, the gas flow enters from the right end of the horizontal air passage 1011 and flows to the left, flows through the horizontal air passage 1011 into the vertical air passage 1012 to change the direction, flows downward in the vertical air passage 1012, and is discharged. The left end of the horizontal air passage 1011 is provided with a smooth guide angle transition to make the gas enter the vertical air passage 1012 smoothly. The specific structure of the gas flow passage 101 is not limited to the structure shown in the figure, and other structure forms such as a straight-through cavity can also be used, and these specific structures also belong to the protection scope of the present application.

[0043] The inlet end of the gas flow passage 101 is provided with a first stepped groove 102, as shown in the figure. Figure 4 The first stepped groove 102 is provided at the right end of the horizontal air passage 1011 and at the right end of the entire gas flow passage 101. The cross sections of the gas flow passage 101 and the first stepped groove 102 are circular, wherein the main body of the horizontal air passage 1011 is cylindrical, the left end is a smooth reduced spherical surface, the vertical air passage 1012 is cylindrical, and the first stepped groove 102 is cylindrical. The diameter of the first stepped groove 102 is larger than the diameter of the gas flow passage 101, as shown in the figure, D1 is the diameter of the gas flow passage 101, D2 is the diameter of the first stepped groove 102, D3 is the diameter of the second stepped groove 103, and D1 < D2 < D3. The present application does not exclude that the gas flow passage 101 and the first stepped groove 102 adopt other shapes such as elliptical, rectangular, square, etc., and the cross-sectional area of the first stepped groove 102 should be larger than that of the horizontal air passage 1011. Figure 4

[0044] Due to the size change between the first stepped groove 102 and the gas flow passage 101, a first step surface 1021 is formed at the junction between the first stepped groove 102 and the gas flow passage 101, and the surface of the first step surface 1021 is perpendicular to the axis direction of the horizontal air passage 1011. The filter screen 20 is welded and fixed on the first step surface 1021 at the junction between the first stepped groove 102 and the gas flow passage 101, and the filter screen 20 is fixedly connected with the gas passage structure 10 by welding.

[0045] As shown in the figure, Figure 2 , Figure 3 The diameter of the filter screen 20 is larger than the diameter of the gas flow passage 101 to ensure that the filter screen 20 completely covers the gas flow passage 101, and the gas passing through the gas flow passage 101 will pass through the filter screen 20 without omission. A plurality of fine small holes are provided through the filter screen 20 to allow the gas flow to pass through, when the gas flow passes through the filter screen 20, on the one hand, the gas flow can be filtered to remove the particulate matter carried in the gas flow, and on the other hand, the uniform and fine small holes make the gas flow form a uniform distribution.

[0046] ​The gas mass flow controller filtering structure of the present application fixes the filter screen 20 by welding. The filter screen 20 is welded to the gas path structure 10 and fixed as a whole with the gas path structure 10. There is no assembly gap between the filter screen 20 and the gas path structure 10, so the particle cleaning problem caused by the pulsating friction of the traditional clamping slot filter screen structure under dynamic flow disturbance can be avoided. The filter screen 20 is fixed by welding at the periphery, and the welding fixing points form a tension effect around the filter screen 20, which improves the support performance of the filter screen 20. The filter screen 20 can be provided with small and dense holes without reducing the structural strength, so it is not necessary to additionally provide a supporting screen. Compared with the existing double-layer filter screen structure, only one layer of filter screen 20 is needed, which avoids the problem of flow uniformity decline caused by the double-layer filter screen, and the single-layer filter screen has good flow uniformity, which helps to improve the flow detection accuracy and is more simple. The filter screen 20 is fixed to the gas path structure 10 by welding, so only one surface of the filter screen 20 contacts the gas path structure 10, and the filter screen 20 will not be extruded. Compared with the existing mechanical extrusion fixing method of the filter screen 20 on both sides, the phenomenon of particle generation caused by excessive extrusion can also be avoided.

[0047] Embodiment two:

[0048] The main feature of the present embodiment is the welding form of the filter screen 20.

[0049] The filter screen 20 is fixed to the gas path structure 10 by welding, and the periphery of the filter screen 20 is fully welded or uniformly spot welded. In combination with Figure 5 , it is shown that the periphery of the filter screen 20 is fully welded to the gas path structure 10, that is, the welding seam 30 is completely distributed around the filter screen 20, and the welding seam 30 is formed in a circular ring shape by welding at each position of the 360° contact between the filter screen 20 and the gas path structure 10. In combination with Figure 6 , it is shown that the periphery of the filter screen 20 is uniformly spot welded, and the entire welding seam is composed of a plurality of independent welding points. The welding points are discontinuous and spaced apart from each other, and the entire welding seam is composed of a plurality of welding points uniformly distributed around the circumference. Each welding point can be located on the same circumference or distributed on two or more circumferences of different sizes. Each welding point can be a round point or an arc. Regardless of which welding seam form is used, the filter screen 20 must be fixed firmly and stably. The periphery of the filter screen 20 can be fully welded or spot welded according to specific needs. For example, based on the flow and pressure, the periphery of the filter screen 20 can be fully welded or uniformly spot welded to reasonably control the welding cost. The larger the flow and pressure, the longer the welding seam should be.

[0050] The filter screen 20 and the air path structure 10 are both made of metal material, the filter screen 20 is fixed by laser protection welding or vacuum diffusion welding, that is, the welding mode between the filter screen 20 and the air path structure 10 can be variously selected. The filter screen 20 can be welded by laser protection welding and vacuum diffusion welding, which can maximize the guarantee of not introducing impurities while meeting the demand of welding strength.

[0051] Embodiment three:

[0052] The main feature of the embodiment is the structure of the filter screen 20.

[0053] The filter screen 20 can be processed in different structures. The filter screen 20 can be composed of woven metal wire, and the metal filter screen 20 is usually composed of woven metal (such as 316L) wire. In addition, the filter screen 20 can also be punched on a flat plate. In combination with Figure 1 、 Figure 2 、 Figure 3 It is shown that the filter screen 20 is a circular flat plate, and a plurality of array holes are processed on the surface of the circular flat plate, so that the gas flow passes through the screen holes, and the filtering and flow uniformizing effects are achieved.

[0054] For the filter screen 20 composed of woven metal wire, the filter screen 20 is provided with single-layer or multi-layer woven metal wire, and the metal wire can adopt a grid structure formed by mutual superposition and interpenetration. The metal wire that is mutually superposed and interpenetrated can be a plurality of warp threads and a plurality of weft threads that are perpendicular to each other, or other angle grids; the shape of the grid can be a square, a rectangle, a regular polygon, etc.

[0055] The filter screen 20 is a planar screen, as shown in Figure 2 、 Figure 3 The filter screen 20 is a sheet-shaped grid structure. The utility model should also include the case that the filter screen 20 adopts a spherical surface structure, for example, the convex direction of the filter screen 20 is toward the air inlet direction, and the entering gas flow impacts on the convex spherical filter screen 20.

[0056] Embodiment four:

[0057] The main feature of the embodiment is the structure design of the air path structure 10.

[0058] The flow channel surface of the air flow channel 101 is treated by fluid polishing or electrolytic polishing, and the high smoothness surface after precision machining ensures the cleanliness of the air flow channel 101, facilitates purging, and removes particles.

[0059] The first stepped groove 102 is provided with a second stepped groove 103, and the diameter of the second stepped groove 103 is greater than that of the first stepped groove 102, as shown in Figure 4The diameter D3 of the second stepped groove 103 is greater than the diameter D2 of the first stepped groove 102. The diameter of the second stepped groove 103 is further increased on the basis of the first stepped groove 102, and a second stepped surface 1031 with a size mutation is formed at the junction of the second stepped groove 103 and the first stepped groove 102, and the second stepped surface 1031 is perpendicular to the airflow direction. The second stepped groove 103 is used for inserting the gas pipeline, and facilitates the butt joint and fixation of the gas pipeline.

[0060] Embodiment five:

[0061] The application also provides a gas delivery pipeline system, which comprises a filter, a diaphragm valve and a gas mass flow controller, and the gas mass flow controller adopts the gas mass flow controller filter structure. The gas mass flow controller is applied to an ultrahigh-purity and ultraclean gas delivery pipeline system, and is combined with Figure 9 As shown, wherein P1 represents a pressure gauge, the upstream of the pressure gauge P1 is a pressure regulating valve V3, F1 / F2 is a filter, V1 / V2 is a diaphragm valve, MFC1 and MFC2 are gas mass flow controllers. The clean filter structure inside the MFC is particularly important, the internal particles potentially affect the function of the flow meter itself and the cleanliness of the overall gas circuit. For the scene where no additional filter components are set downstream of the MFC, the clean filter structure inside the MFC itself is particularly important, and the use of the gas mass flow controller filter structure provided by the application helps to improve the cleanliness inside the MFC.

[0062] The gas mass flow controller filter structure of the application is provided with a single-piece metal filter screen 20, which is welded and fixed with the gas circuit structural part 10, the structure is firm and stable, after the airflow passes through, the filter screen 20 and the gas circuit structural part 10 will not move relatively to generate friction and particles, and the single-piece metal filter screen 20 can form 100% complete coverage of the airflow passage 101 area, with high interception efficiency, which can achieve high cleanliness.

[0063] The filter screen 20 adopts a welded assembly structure, which is very stable during use, and can avoid the problem of particle generation caused by non-pulsating friction of the filter screen in a dynamic airflow environment

[0064] The gas mass flow controller filter structure of the application can also be applied to other components with high cleanliness requirements, such as flow meters, flow controllers, control valves with particle interception requirements, etc., which can achieve the same benefits.

[0065] The above preferred embodiments further illustrate the purpose, technical solutions and advantages of the application. It should be understood that the above is only a preferred embodiment of the application and does not limit the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A gas mass flow controller filter structure, characterized by, The application relates to a gas mass flow controller filter structure. The gas path structure (10) is provided with a gas flow channel (101), and the inlet end of the gas flow channel (101) is provided with a first stepped groove (102) with a diameter larger than that of the gas flow channel (101); the filter screen (20) is welded and fixed on a first step surface (1021) at the joint of the first stepped groove (102) and the gas flow channel (101), and the diameter of the filter screen (20) is larger than that of the gas flow channel (101) so as to completely cover the gas flow channel (101). The circumferential edge of the filter screen (20) is fully welded or uniformly spot welded.

2. The gas mass flow controller filter structure of claim 1, wherein, The filter screen (20) is fixed by laser protective welding or vacuum diffusion welding.

3. The gas mass flow controller filter structure of claim 1, wherein, The filter screen (20) is a woven metal wire screen or is punched on a flat plate.

4. The gas mass flow controller filter structure of claim 1, wherein, The filter screen (20) is provided with single-layer or multi-layer woven metal wires.

5. The gas mass flow controller filter structure of claim 4, wherein, The filter screen (20) is a flat screen.

6. The gas mass flow controller filter structure of claim 1, wherein, The flow channel surface of the gas flow channel (101) is treated by fluid polishing or electrolytic polishing.

7. The gas mass flow controller filter structure of claim 1, wherein, The inlet end of the first stepped groove (102) is provided with a second stepped groove (103) with a diameter larger than that of the first stepped groove (102), and a second step surface (1031) is formed at the joint of the second stepped groove (103) and the first stepped groove (102), and the second stepped groove (103) is used for inserting and mounting a gas pipeline.

8. The gas mass flow controller filter structure of claim 1, wherein, The gas mass flow controller adopts the gas mass flow controller filter structure according to any one of claims 1 to 8.

9. A gas delivery line system comprising a filter, a diaphragm valve, and a gas mass flow controller, characterized by, ​

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