Particle separator

Abstract

A pre-pump type sub-atmospheric pressure particle separator includes: an inlet duct configured to receive a sub-atmospheric pressure waste gas flow from a semiconductor processing tool; and a counter-current cyclone having an inlet orifice fluidly connected to the inlet duct and located adjacent to an enlarged end, a particle trap located adjacent to a narrowed end away from the enlarged end, and an outlet located adjacent to the enlarged end. The inlet duct includes a baffle structure located therein, the baffle structure being configured to guide the waste gas flow through the inlet duct and tangentially into the cyclone.

Description

Technical Field

[0001] This invention relates to a particle separator. Background Technology

[0002] Particulate separators are known. These separators are used to remove particles from exhaust gas streams.

[0003] While these separators provide the ability to remove particles from the exhaust gas stream, they have several drawbacks. Therefore, an improved particle separator is desired. Summary of the Invention

[0004] According to a first aspect, a pre-pump type subatmospheric particulate separator is provided, comprising: an inlet duct configured to receive a subatmospheric waste gas stream from a semiconductor processing tool; and a counter-current cyclone having an inlet orifice, a particulate trap, and an outlet, the inlet orifice being fluidly connected to the inlet duct and positioned adjacent to an enlarged end, the particulate trap being positioned adjacent to a constricted end away from the enlarged end, and the outlet being positioned adjacent to the enlarged end. The inlet duct includes a baffle structure located therein, the baffle structure being configured to guide the waste gas stream flow through the inlet duct and tangentially into the cyclone. The first aspect recognizes that one problem with existing separators is that, typically, particulate separation of subatmospheric gas streams involves the use of filters or other media traps, which can be problematic, particularly for waste gas streams from semiconductor processing tools that may contain problematic chemicals and require long-term reliable operation.

[0005] Therefore, a particle separator is provided. The particle separator may be a subatmospheric pressure particle separator. The particle separator may be a pre-pump type particle separator. In other words, the particle separator may be located upstream of a pump. The particle separator may include an inlet conduit. The inlet conduit may be configured or adapted to receive or deliver subatmospheric pressure waste gas from a semiconductor processing tool. The particle separator may include a cyclone separator. The cyclone separator may be a counter-current cyclone separator. The cyclone separator may have an inlet orifice. The inlet orifice may be fluidly connected to the inlet conduit. The inlet orifice may be located or positioned adjacent to, toward, near, or within the enlarged end of the cyclone separator. A particle trap may be located or positioned adjacent to, toward, near, or within the narrowed end of the cyclone separator. The narrowed end may be located away from or positioned away from the enlarged end. The cyclone separator may include an outlet located or positioned adjacent to, toward, near, or within the enlarged end. The inlet conduit may include a baffle structure or arrangement. The baffle structure can be located within the inlet duct. The baffle structure can be configured or arranged to guide or transport the waste gas flow through the inlet duct. The baffle structure can be configured to guide the waste gas flow tangentially or with a tangential component into the cyclone separator. In this way, particles in the sub-atmospheric pressure waste gas flow can be captured by the particulate filter, thereby achieving effective separation of particles from the sub-atmospheric pressure waste gas flow and providing long-term reliable operation.

[0006] The baffle structure defines an open area and a closed area within the inlet duct. The open area facilitates the tangential flow of the waste gas into the cyclone separator, while the closed area impedes the flow of the waste gas. Therefore, the baffle structure divides the inlet duct into an area through which the waste gas can flow and an area that impedes its flow.

[0007] The baffle structure may include a guide vane extending generally along the elongated axis of the inlet duct to guide the exhaust gas flow tangentially into the cyclone separator. Therefore, the guide vane can control the flow of the exhaust gas flow to deliver it tangentially or with a tangential flow component into the cyclone separator.

[0008] The guide vane can be oriented to narrow the open area along the elongated axis of the inlet duct toward the cyclone separator, thereby guiding the waste gas flow tangentially into the cyclone separator. This narrowing not only helps guide the waste gas flow into the cyclone separator but also helps increase the velocity of the waste gas entering the cyclone separator, thus improving separation efficiency.

[0009] The size of the guide plate can be designed to extend into the cyclone. Therefore, the plate itself can extend into the cyclone, which further helps guide the flow of exhaust gas already within the cyclone.

[0010] The baffle structure may include a blocking element configured to define the enclosed area to prevent the exhaust gas from flowing back from the cyclone into the inlet duct. This helps prevent backflow into the inlet duct and prevents eddies from disrupting the circumferential flow within the cyclone.

[0011] The inlet conduit may have a circular cross-section, and the baffle may be oriented such that its leading edge forms a chord, the chord defining an open sector as the open region. The blocking element may include a sector plate that spans the inlet conduit extension between the baffle and the inner surface of the inlet conduit, thereby defining a closed sector as the closed region.

[0012] The cyclone separator may include a cylindrical chamber defining the enlarged end and a conical chamber sharing a common axis and defining the narrowed end. The inlet duct may be positioned to overlap with the common axis, and the baffle structure may be configured to prevent the exhaust gas from flowing non-tangentially around the common axis into the cylindrical chamber.

[0013] The outlet may be provided by an outlet duct extending from the cylindrical chamber, and the baffle structure may be configured to guide the waste gas flow tangentially into the cyclone located between the cylindrical chamber and the outlet duct.

[0014] The outlet conduit can be designed to extend into the cylindrical chamber and beyond the inlet orifice. This helps prevent the exhaust gas flow from bypassing the conical chamber, thereby improving the particle separation efficiency of the cyclone separator.

[0015] The outlet conduit may have a radially extending upper support with a circumferential seal and an annular plate surrounding the outlet conduit, the annular plate being configured to retain the outlet conduit within the cylindrical cavity and close the enlarged end. This facilitates the simplification of separator manufacturing by aiding in the precise positioning of the outlet conduit within the cyclone separator.

[0016] The outlet duct may have a radially extending lower support configured to retain the outlet duct within the cylindrical chamber. This helps simplify the manufacture of the cyclone, particularly for those with a high axial length-to-diameter ratio, which facilitates the removal of particles from the subatmospheric exhaust gas stream with the desired removal efficiency.

[0017] The inlet duct and / or the outlet duct may include a flow direction changing structure configured to change the flow direction of the waste gas flow.

[0018] The flow direction changing structure can be configured to provide orthogonal and / or reverse flow direction to the waste gas flow.

[0019] The particulate trap may include a closure configured to fluidly isolate the particulate trap from the cyclone to facilitate particulate removal during subatmospheric operation.

[0020] The particle separator may include multiple particle traps. This can help facilitate continuous operation by allowing one particle trap to be isolated for emptying while another particle trap remains operational.

[0021] The particle separator may include a vacuum pump connected to the outlet.

[0022] The inlet conduit may include a front-end conduit that can be connected to the semiconductor processing tool.

[0023] The pre-pipeline, the counter-current cyclone separator, and the vacuum pump can be connected in series via fluid connection.

[0024] The diameter of the cylindrical chamber can be approximately 1.2 to 1.4 times the diameter of the inlet conduit.

[0025] The height of the conical chamber can be approximately 2 to 2.25 times the diameter of the inlet conduit.

[0026] The height of the cylindrical chamber can be approximately 1.3 to 1.5 times the diameter of the inlet conduit.

[0027] The outlet conduit can be positioned to extend into the cylindrical chamber a distance approximately 1.15 times the diameter of the inlet conduit. In other words, the outlet can be positioned within the cylindrical chamber at approximately 1.15 times the diameter of the inlet conduit.

[0028] Further specific and preferred aspects are set forth in the appended independent and dependent claims. Features of the dependent claims may be suitably combined with features of the independent claims, and in other combinations not expressly set forth in the claims.

[0029] When a device feature is described as operable to provide a certain function, it should be understood that this includes device features that provide that function or are adapted or configured to provide that function. Attached Figure Description

[0030] Embodiments of the present invention will be further described with reference to the accompanying drawings, in which: Figure 1 This is a perspective view of a particle separator according to one embodiment; Figure 2 yes Figure 1 A cross-sectional view of a particle separator; Figure 3 This is a more detailed perspective view of a counter-current cyclone separator; Figure 4 yes Figure 3 A partial cross-sectional view of the counter-current cyclone shown in the image; Figure 5 An arrangement for securing the first cylindrical portion within the cylindrical cavity is shown; and Figure 6 The arrangement of a pair of particle traps is shown, with the conical chamber narrowed at its narrow end. Detailed Implementation

[0031] Before discussing the embodiments in more detail, an overview is first provided. Some embodiments provide a particle separator assembly for removing particles from the exhaust gas stream of a semiconductor processing tool. The particle separator arrangement typically includes: a coupling for connection to a pre-running pipeline of the semiconductor processing tool; a cyclone separator; and a vacuum pump for drawing the exhaust gas stream from the semiconductor processing tool, passing it through the pre-running pipeline and coupling, through the cyclone separator, and into the vacuum pump. The cyclone separator provides simple, typically continuous, mechanical separation of particles from the exhaust gas stream without the need for additional chemicals that may pose an adverse reaction risk or filters or matrices that may become clogged. The coupling is configured to connect to a conventional vacuum coupling, and the construction of the cyclone separator, along with the baffle structure at the cyclone separator inlet, contributes to improved particle separation efficiency at sub-atmospheric pressure.

[0032] Figure 1 This is a perspective view of a particle separator 10 according to one embodiment. Figure 2 yes Figure 1 A cross-sectional view of a particle separator 10. The particle separator 10 is a sub-atmospheric pressure particle separator located upstream of a vacuum pump (not shown). The particle separator 10 has an inlet duct 20 that receives exhaust gas from a pre-line of a semiconductor processing tool (not shown), and the inlet duct 20 is connected to a downstream counter-current cyclone separator 30. The counter-current cyclone separator 30 is connected to a particle trap (not shown) and a downstream outlet duct 40. The outlet duct 40 is connected to the vacuum pump.

[0033] The inlet duct 20 has an inlet hole 22, which has a circular cross-section and forms a 90° elbow bend 24. Downstream of the elbow bend 24 is an elongated cylindrical duct 26, which is connected to the downstream inlet hole 32 of the counter-current cyclone separator 30.

[0034] The counter-current cyclone separator 30 includes a cylindrical chamber 34 connected at one end to a conical chamber 36. The conical chamber 36 narrows away from the cylindrical chamber 34 and terminates at the particle trap assembly 50. The cylindrical chamber is closed at its other end by an annular plate 38, which receives a first cylindrical portion 42 of the outlet conduit 40.

[0035] Downstream of the first cylindrical portion 42 is the U-shaped bend 44 of the outlet conduit 40. Downstream of the U-shaped bend 44 is the second cylindrical portion 46. The outlet conduit 40 has an inlet port 48 located within a cylindrical chamber 34. The first cylindrical portion 42 is concentrically positioned within the cylindrical chamber 34. The first cylindrical portion 42 extends axially within the cylindrical chamber 34 to extend beyond the inlet port 32. This positions the inlet port 48 towards the conical chamber 36, below the inlet port 32.

[0036] Although the elbow bend 24 and the U-bend 44 are provided in this embodiment, it should be understood that these components can be omitted or changed if the placement of the inlet conduit 20 to be connected to the pre-stage pipeline and the placement of the outlet conduit 40 to be connected to the inlet of the downstream vacuum pump are oriented or positioned in different locations.

[0037] The diameter B of the cylindrical chamber 34 is typically about 1.2 to 1.4 times the diameter A of the inlet conduit 20. The height C of the conical chamber 36 is typically about 2 to 2.25 times the diameter A of the inlet conduit 20. The height D of the cylindrical chamber 34 is typically about 1.3 to 1.5 times the diameter A of the inlet conduit 20. The outlet conduit 40 can typically be positioned to extend into the cylindrical chamber 34 a distance E, which is about 1.15 times the diameter A of the inlet conduit 20. In other words, the outlet 48 is typically positioned in the cylindrical chamber 34 at about 1.15 times the diameter A of the inlet conduit 20.

[0038] Figure 3 This is a more detailed perspective view of the counter-current cyclone separator 30. Figure 4 yes Figure 3The diagram shows a partial cross-sectional view of the counter-current cyclone separator 30. As can be seen, the centerline of the inlet orifice 32 is not centered with the centerline of the counter-current cyclone separator 30, but is offset to one side. A baffle structure is provided, comprising a guide vane 60 and a fan-shaped plate 62. The guide vane 60 extends from the interior of the cylindrical chamber 34 through the inlet orifice 32 and into the cylindrical duct 26. The guide vane 60 extends fully between the opposing surfaces of the inlet duct 20, defining a chord in cross-section. The guide vane 60 is not axially aligned with the centerline of the inlet duct 20, but is angularly offset (not parallel to the axis of the inlet duct 20), such that the cross-sectional area of ​​the space in which the exhaust gas flows decreases toward the counter-current cyclone separator 30. In other words, the guide vane 60 is positioned and oriented to extend approximately tangentially into the cylindrical chamber 34. The fan-shaped plate 62 defines a fan-shaped area that blocks the inlet duct 20 on the closed (blind) side of the guide vane 60.

[0039] Figure 5 The arrangement for securing the first cylindrical portion 42 within the cylindrical chamber 34 is illustrated. Specifically, an annular retainer, in the form of an elastic seal 45, is secured to the outer surface of the first cylindrical portion 42 using a plurality of radially extending support strips 47. This allows the first cylindrical portion 42 to be positioned within the cylindrical chamber 34, wherein the seal 45 is pressed against the inner surface of the cylindrical chamber 34 to coaxially hold the first cylindrical portion at the desired axial position within the cylindrical chamber 34, thereby positioning the inlet port 48 outside the inlet port 32.

[0040] Figure 6 The arrangement of a pair of particulate traps 52A, 52B at the narrowed end of the conical chamber 36 is shown. Each particulate trap 52A, 52B is individually actuable, such that one particulate trap can be emptied while the other particulate trap remains in use.

[0041] In operation, a vacuum pump (not shown), connected to the outlet port 49 of the outlet duct 40, draws waste gas from the pre-line (not shown) of the semiconductor processing tool via the inlet port 22. The waste gas carries suspended particles that are to be removed. The waste gas flows through the elbow bend 20 into the cylindrical duct 26. A baffle 60 defines a narrowing gap within the inlet duct 20 through which the waste gas flows. The narrowing toward the counter-current cyclone 30 increases the velocity of the waste gas. The orientation and positioning of the baffle 60 cause the waste gas to flow approximately tangentially into the cylindrical chamber 34. This causes the waste gas to flow circumferentially around the cylindrical chamber 34. The combination of the fan-shaped plate 62 and the baffle 60 helps maintain the approximately circumferential flow of the waste gas within the cylindrical chamber 34. The waste gas flow continues into the conical chamber 36, and particles within the waste gas flow fall from the waste gas flow and move towards the particle trap assembly 50 at the narrowing end of the conical chamber 36. The particle-free waste gas flow flows into the inlet orifice 48 and through the outlet conduit 40 to the vacuum pump. When... Figure 5 When the arrangement shown is in operation, one of the particle traps 52A is activated to allow particulate matter to be removed while the vacuum pump remains running, and vice versa, thus allowing the particle separator to operate continuously.

[0042] Most chemical reaction byproducts in semiconductor chambers are drawn into dry vacuum pumps as powder or particles. The difference between vacuum range and temperature causes instantaneous changes in the physical properties of these byproducts. These powder deposits can cause a range of problems, such as pump jamming or stopping, increased energy consumption, etc. In particular, large amounts of byproduct powder can be generated during the process, and powder accumulation leads to pressure drops. This results in shortened pump life during demanding processes. Pump failures cause backflow to the tool. However, because the internal physical environment of the pump and chamber can be difficult to alter, powder becomes a problem, and a filtration device is desired to reduce powder in the dry pump. Therefore, the primary objective is to improve or extend pump life by trapping powder before the pump. Consequently, some embodiments provide a device configured to be installed before a dry pump that improves dry pump life by separating powder or other particles from process gases or exhaust gases before the dry pump. The device is designed to allow gas to enter the device and cause a cyclone to rotate to separate powder from the process gas. This approach helps improve pump life in demanding semiconductor processes. It also helps address process backflow from the pump and helps reduce steady loads on the pump or avalanche-like buildup of powder. Specifically, some embodiments provide a metal tube with internal baffles designed to create vortices in the incoming gas, and an internal gas cyclone separator that uses centrifugal force to expel the powder. This cyclone collector operates through physical treatment, which does not alter the chemical structure of the exhaust gas flow, thus reducing risk. Particles naturally fall by gravity and are collected by a container below. Pressure loss should be considered since the cyclone collector is installed before the dry pump. However, simulations show that the pressure drop is only 7.72 Pa when the inlet gas is 5 slm.

[0043] Although illustrative embodiments of the invention have been disclosed in detail herein with reference to the accompanying drawings, it should be understood that the invention is not limited to the precise embodiments, and that various changes and modifications can be made therein by those skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.

[0044] List of reference numerals Particle separator 10 Inlet catheter 20 Inlet hole 22 Elbow-shaped bend 24 Cylindrical conduit 26 Counter-current cyclone separator 30 Inlet hole 32 Cylindrical chamber 34 Conical chamber 36 Annular plate 38 Outlet conduit 40 First cylindrical section 42 U-shaped bend section 44 Seal 45 Second cylindrical section 46 Support bar 47 Inlet hole 48 Outlet hole 49 Particle trap assembly 50 Particle traps 52a, 52b Deflector 60 Sector plate 62

Claims

1. A pre-pump type sub-atmospheric pressure particle separator, comprising: An inlet duct configured to receive sub-atmospheric pressure exhaust gas from a semiconductor processing tool; as well as A counter-current cyclone separator having an inlet orifice, a particulate trap, and an outlet, the inlet orifice being fluidly connected to an inlet duct and located adjacent to an enlarged end, the particulate trap being located adjacent to a narrowed end away from the enlarged end, and the outlet being located adjacent to the enlarged end. The inlet duct includes a baffle structure located therein, the baffle structure being configured to guide the exhaust gas flow through the inlet duct and tangentially into the cyclone separator.

2. The particle separator according to claim 1, wherein, The baffle structure defines an open area and a closed area within the inlet duct. The open area facilitates the tangential flow of the waste gas into the cyclone, while the closed area prevents the waste gas from flowing.

3. The particle separator according to claim 1 or 2, wherein, The baffle structure includes a guide plate that extends generally along the elongated axis of the inlet duct to guide the exhaust gas flow tangentially into the cyclone.

4. The particle separator according to claim 3, wherein, The baffle is oriented to narrow the open area toward the cyclone along the elongated axis of the inlet duct, so as to guide the exhaust gas flow tangentially into the cyclone.

5. The particle separator according to claim 3 or 4, wherein, The size of the deflector is designed to extend into the cyclone.

6. The particle separator according to any one of the preceding claims, wherein, The baffle structure includes a blocking element configured to define the enclosed area to prevent the exhaust gas flow from the cyclone back into the inlet duct.

7. The particle separator according to any one of claims 3 to 6, wherein, The inlet conduit has a circular cross-section, and the guide plate is oriented such that its leading edge forms a chord, the chord defining an open sector as the open region, and wherein the blocking member includes a sector plate that spans the inlet conduit extension between the guide plate and the inner surface of the inlet conduit, thereby defining a closed sector as the closed region.

8. The particle separator according to any one of the preceding claims, wherein, The cyclone includes a cylindrical chamber defining the enlarged end and a conical chamber sharing a common axis and defining the narrowed end, the inlet duct being positioned to overlap with the common axis, and the baffle structure being configured to prevent the exhaust gas flow from entering the cylindrical chamber in a non-tangential manner around the common axis.

9. The particle separator according to claim 8, wherein, The outlet is provided by an outlet duct extending from the cylindrical chamber, and the baffle structure is configured to guide the exhaust gas flow tangentially into the cyclone located between the cylindrical chamber and the outlet duct.

10. The particle separator according to claim 9, wherein, The outlet conduit is sized to extend into the cylindrical chamber and beyond the inlet orifice.

11. The particle separator according to claim 9 or 10, wherein, The outlet conduit has a radially extending upper support member with a circumferential seal and an annular plate disposed around the outlet conduit, the annular plate being configured to retain the outlet conduit within the cylindrical cavity and close the enlarged end.

12. The particle separator according to any one of claims 9 to 11, wherein, The outlet conduit has a radially extending lower support configured to retain the outlet conduit within the cylindrical cavity.

13. The particle separator according to any one of claims 9 to 12, wherein, The inlet duct and / or the outlet duct includes a flow direction changing structure configured to change the flow direction of the waste gas flow.

14. The particle separator according to claim 13, wherein, The flow direction changing structure is configured to cause the flow direction of the waste gas to undergo orthogonal and / or reverse reversal.

15. The particle separator according to any one of the preceding claims, wherein, The particulate trap includes a closure configured to fluidly isolate the particulate trap from the cyclone separator to facilitate particulate removal during subatmospheric operation.

16. The particle separator according to any one of the preceding claims, comprising a plurality of the particle traps.

17. The particle separator according to any one of the preceding claims, comprising a vacuum pump connected to the outlet.

18. The particle separator according to any one of the preceding claims, wherein, The inlet conduit includes a front-end conduit that can be connected to the semiconductor processing tool.

19. The particle separator according to claim 18, wherein, The pre-pipeline, the counter-current cyclone separator, and the vacuum pump are connected in series via fluid connection.

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