Cavity air exhaust hole filter screen applied to ALD (atomic layer deposition) equipment

Abstract

The invention discloses a cavity exhaust hole filter screen applied to ALD (atomic layer deposition) equipment, relates to the technical field of atomic layer deposition, and aims to solve the problems that an existing filter screen for atomic layer deposition is easy to block and poor in filtering effect. Comprising multiple layers of filter screens arranged in an air exhaust pipeline, and the sizes of meshes of the multiple layers of filter screens are gradually reduced in the direction away from an inlet of the air exhaust pipeline; air flow of the reaction cavity passes through the multiple layers of filter screens to be filtered in a classified mode, and the air flow filtered in a classified mode enters the vacuum pump. The cavity exhaust hole filter screen applied to the ALD equipment can effectively filter particles in airflow, and the service life of the filter screen is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of atomic layer deposition, and particularly to a filter screen for the cavity air extraction hole of an ALD device. Background Art

[0002] The ALD (Atomic Layer Deposition) atomic layer deposition process is a method for precisely controlling the film thickness and composition at the micro-nano scale, and its temperature has an important influence on the deposition process and film properties. During the atomic layer deposition process, a vacuum environment needs to be provided for the reaction chamber by a vacuum pump. In order to prevent the particulate matter generated in the reaction chamber from being extracted into the vacuum pump by the vacuum pump during the air extraction process and causing pollution to the vacuum pump, usually a layer of filter screen is set at the outlet of the reaction chamber or in the air extraction pipeline connecting the reaction chamber and the vacuum pump to intercept the particulate matter. However, if a small-aperture filter screen is selected, the small-aperture filter screen will be directly exposed to the front end of the air flow, and particles such as unreacted precursor clusters and debris falling off inside the chamber will quickly block its pores, resulting in a greatly shortened service life of the filter screen and unable to ensure long-term stable filtration. If a large-aperture filter screen is selected, fine particles such as nanoscale dust will penetrate the filter screen, polluting downstream equipment such as the vacuum pump or causing excessive emissions. Summary of the Invention

[0003] The purpose of the present invention is to provide a filter screen for the cavity air extraction hole of an ALD device, which can effectively filter and intercept the particulate matter in the air flow and improve the service life of the filter screen.

[0004] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0005] A filter screen for the cavity air extraction hole of an ALD device includes multiple layers of filter screens arranged in the air extraction pipeline. Along the direction away from the inlet of the air extraction pipeline, the pore sizes of the multiple layers of filter screens gradually decrease; the air flow in the reaction chamber passes through the multiple layers of filter screens to achieve hierarchical filtration of the air flow, and the hierarchically filtered air flow enters the vacuum pump.

[0006] Optionally, the centers of the multiple layers of filter screens are located on the same vertical line, and the intervals between the multiple layers of filter screens are the same, and the interval is greater than or equal to 20 mm.

[0007] Optionally, the multiple layers of filter screens include a first filter screen and a second filter screen. The first filter screen is the layer of filter screen farthest from the inlet of the air extraction pipeline, and the second filter screen is the layer of filter screen closest to the inlet of the air extraction pipeline. The mesh number of the first filter screen is 80 mesh, and the mesh number of the second filter screen is 30 mesh.

[0008] Optionally, the pore shapes of the multiple layers of filter screens are circular, square or diamond-shaped.

[0009] Optionally, the shapes of the multi-layer filter screens are all circular, and the diameters of the multi-layer filter screens are the same as the diameter of the air extraction pipe.

[0010] Optionally, the multi-layer filter screens are perpendicular to the pipe wall of the air extraction pipe.

[0011] Optionally, adjacent two layers of filter screens are connected by a detachable bracket.

[0012] Optionally, the detachable bracket is a hollow tube structure, the hollow tube structure includes a plurality of cylinder segments and annular grooves, adjacent two cylinder segments are connected by the annular grooves, the annular grooves are recessed along the central axis direction of the hollow tube structure, the annular grooves are used for installing sealing rings, the number of the cylinder segments is the same as the number of layers of the multi-layer filter screens, and one layer of filter screen is installed in each cylinder segment.

[0013] Optionally, the multi-layer filter screens all include metal rings and filter plates, the filter plates are fixed on the inner ring surfaces of the metal rings, and the filter plates are composed of a plurality of cross-arranged metal wires.

[0014] Optionally, the filter plates are plain weave structures, twill weave structures or sintered mesh structures.

[0015] Compared with the prior art, a filter screen for a cavity air extraction hole applied to an ALD device provided by the present invention includes a multi-layer filter screen arranged in an air extraction pipe. Along the direction away from the air extraction pipe inlet, the mesh sizes of the multi-layer filter screens gradually decrease; the air flow in the reaction cavity passes through the multi-layer filter screens to realize the hierarchical filtration of the air flow, and the hierarchically filtered air flow enters a vacuum pump. The filter screen with a large aperture is near the pipe inlet, and large particle substances can be filtered out through the filter screen with a large aperture. Then, as the mesh size of the filter screen decreases, the interception of small-aperture or even nano-scale particles can be realized, so as to complete the efficient capture of full-size particles. And by intercepting large particles first, the small-aperture filter screen is not easy to be blocked, thereby prolonging the service life of the filter screen and reducing the maintenance efficiency. In addition, the large-aperture filter screen serves as a buffer layer to slow down the rising speed of the pressure drop, and the air flow can still be maintained stable even if it is partially blocked. In addition, through hierarchical filtration, the risk of particles entering the vacuum pump is almost eliminated, and the service life of the vacuum pump is prolonged. Description of the Drawings

[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0017] Figure 1 It is a schematic structural diagram of the multi-layer filter screen provided by the present invention;

[0018] Figure 2Structural schematic diagram of the detachable bracket corresponding to the double-layer filter screen provided by the present invention.

[0019] Reference numerals:

[0020] 1 - Air extraction pipeline, 2 - Multi-layer filter screen, 21 - First filter screen, 22 - Second filter screen, 3 - Hollow tube structure, 31 - First cylindrical section, 32 - Second cylindrical section, 33 - Annular groove. Detailed implementation manners

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0023] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined. The meaning of "several" is one or more unless otherwise specifically defined.

[0024] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0025] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] During the atomic layer deposition process, the chemical reaction of the new atomic film layer is directly associated with the previous layer in such a way that only one atomic layer is deposited per reaction, so it is also called single atomic layer deposition. Atomic layer deposition is to continuously introduce at least two gaseous precursor species onto the substrate in a heated reactor. The chemisorption process automatically terminates when the surface is saturated, and the appropriate process temperature hinders the physical adsorption of molecules on the surface. Atomic layer deposition requires a vacuum environment. Currently, the particulate matter in the gas flow of the reaction chamber is usually filtered by a single-layer filter screen, which is not only prone to clogging, shortening the service life of the filter screen, but also prone to unstable gas flow and requires frequent maintenance and cleaning of the filter screen.

[0027] To solve the above problems, the present invention provides a filter screen for the cavity air extraction hole of an ALD device, which will be described below with reference to the accompanying drawings.

[0028] Please refer to Figure 1 , a filter screen for the cavity air extraction hole of an ALD device provided by the present invention includes: a multi-layer filter screen 2 disposed in the air extraction pipeline 1. Along the direction away from the air extraction pipeline inlet, the mesh size of the multi-layer filter screen 2 gradually decreases, that is, the mesh count gradually increases; wherein, the air extraction pipeline communicates with the reaction chamber and the vacuum pump, the air extraction pipeline inlet is the inlet at the connection with the reaction chamber, and the gas flow in the reaction chamber passes through the multi-layer filter screen to achieve hierarchical filtration of the gas flow, and the hierarchically filtered gas flow enters the vacuum pump.

[0029] As a possible implementation manner, the shapes of the multi-layer filter screens are all circular, the centers of the multi-layer filter screens are located on the same vertical line, the multi-layer filter screens are parallel to each other, and the diameters of the multi-layer filter screens are the same as the diameter of the air extraction pipeline. The multi-layer filter screens are perpendicular to the pipe wall of the air extraction pipeline, and the intervals between the multi-layer filter screens are the same, and the interval is greater than or equal to 20 mm. This distance can effectively achieve buffering, avoiding problems such as unstable gas flow and accumulation and blockage of filtered particulate matter between two filter screens due to too small a distance. The perpendicular arrangement of the filter screen and the air extraction pipeline can distribute the gas flow more evenly, thereby ensuring that impurities in the gas flow are effectively captured, and the flow path of the gas flow on the horizontal filter screen is more stable, reducing the filtration dead angle caused by uneven flow.

[0030] As a possible implementation manner, the mesh shapes of the multi-layer filter screens are circular, square or diamond-shaped.

[0031] As a possible implementation, the multi-layer filter screen includes a first filter screen and a second filter screen. The first filter screen is the layer of filter screen farthest from the inlet of the air extraction pipe, and the second filter screen is the layer of filter screen closest to the inlet of the air extraction pipe. The mesh number of each layer of filter screen can be set according to requirements. The filter screen closest to the inlet of the air extraction pipe serves as the coarse filter layer, which preferentially intercepts large particles. The filter screen farthest from the inlet of the air extraction pipe serves as the fine filter layer, which is used to filter fine particles, such as nanoparticles, to avoid being directly blocked by large particles. Exemplarily, if the number of layers of the multi-layer filter screen is 2, the mesh number of the first filter screen is about 80 meshes, and the mesh number of the second filter screen is about 30 meshes. If the number of layers of the multi-layer filter screen is greater than 2, the mesh number of the filter screen between the first filter screen and the second filter screen is between 30 meshes and 80 meshes, and the difference in mesh number between adjacent two filter screens can be the same or different. Setting the filter screen with the smallest mesh size to 30 meshes can achieve the filtration and interception of nanoparticles. The thickness of the metal wires of each layer of filter screen is the same.

[0032] As an alternative way, the mesh size of each filter screen can also be determined by setting the aperture of the mesh. Exemplarily, the aperture of the mesh of the first filter screen is 0.1 μm, the aperture of the mesh of the second filter screen is greater than or equal to 1 μm, and the aperture of the filter screens between the first filter screen and the second filter screen gradually increases, with a value between 0.1 μm and 1 μm. The aperture of the mesh can also be set according to needs. If the mesh is circular, the aperture of the mesh is the diameter. If the mesh is square, the aperture of the mesh is the side length of the square. If the mesh is rhombus, the aperture of the mesh is the length of the longest diagonal of the rhombus.

[0033] As an alternative way, the multi-layer filter screen all includes a metal ring and a filter screen plate. The filter screen plate is fixed on the inner surface of the inner ring of the metal ring. The filter screen plate is composed of multiple metal wires arranged in a cross pattern. The filter screen plate can be a plain weave structure, a twill weave structure or a sintered mesh structure. The material of the filter screen can be a metal material, a ceramic material, a polymer material, etc.

[0034] As an alternative way, each layer of the multi-layer filter screen can be directly installed in the air extraction pipe. Specifically, it can be connected by a buckle or a screw.

[0035] As an alternative way, adjacent two layers of filter screens are connected by a detachable bracket. The multi-layer filter screen is installed on the detachable bracket and installed in the air extraction pipe through the detachable bracket.

[0036] Specifically, the detachable bracket is of a hollow tube structure with a certain wall thickness. The hollow tube structure includes multiple cylindrical segments and annular grooves provided on the outer surface of the hollow tube structure. The outer surfaces of two adjacent cylindrical segments are connected through the concave surface of the annular groove. The multiple cylindrical segments and the annular grooves are integrally formed. The annular grooves are recessed along the central axis direction of the hollow tube structure and are used for installing sealing rings. The number of cylindrical segments is the same as the number of filter layers of the multi-layer filter. One layer of filter is installed in each cylindrical segment. The diameters of the filter layers are the same as the inner diameters of the cylindrical segments. The outer diameters of the cylindrical segments are the same as the inner diameters of the air extraction pipes. The distance between the central points of two adjacent cylindrical segments is greater than or equal to 20 mm.

[0037] See Figure 2 , when the number of filter meshes of the multi-layer filter is 2, the hollow tube structure 3 includes a first cylindrical segment 31, a second cylindrical segment 32 and an annular groove 33. The first filter 21 is installed in the first cylindrical segment 31, and the second filter 22 is installed in the second cylindrical segment 32.

[0038] A filter screen for the cavity air extraction hole of an ALD device provided by the present invention is provided with a multi-layer filter screen. The filter screen near the pipe inlet is set as a large-aperture filter screen. The large-aperture filter screen can filter out large-particle substances. Then, as the mesh size of the filter screen decreases, the interception of fine particles or even nano-scale particles can be achieved, so as to complete the efficient capture of full-size particles. And by intercepting large particles first, the small-aperture filter screen is not easy to be blocked, thereby prolonging the service life of the filter screen and reducing the maintenance efficiency. In addition, the large-aperture filter screen serves as a buffer layer to slow down the rising speed of the pressure drop. Even if it is partially blocked, the air extraction airflow can still be maintained stable. In addition, through hierarchical filtration, the risk of particles entering the vacuum pump is almost eliminated, and the service life of the vacuum pump is extended by 2-3 times. Experimental data shows that the multi-layer filter screen can reduce the vacuum fluctuation range from 15% to ±3%, significantly improving the process repeatability.

[0039] During specific implementation: the multi-layer filter screen is sequentially installed on the detachable bracket, and then the detachable bracket installed with the filter screen is installed into the air extraction pipe, or each layer of filter screen is directly installed into the air extraction pipe by means of screws, buckles, etc., or the filter screen with the largest mesh size can be installed at the outlet of the reaction cavity, and the remaining filter screens are installed into the air extraction pipe in sequence. After the multi-layer filter screen is installed, the vacuum pump performs the air extraction operation, and the airflow in the reaction cavity is hierarchically filtered through the multi-layer filter screen, and the filtered airflow flows into the vacuum pump.

[0040] In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0041] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the said claims.

Claims

1. A cavity exhaust hole filter screen used in ALD equipment, characterized in that: It includes a multi-layer filter screen arranged in an exhaust pipe, and the mesh size of the multi-layer filter screen gradually decreases along the direction away from the exhaust pipe inlet; the airflow in the reaction chamber passes through the multi-layer filter screen to achieve graded filtration of the airflow, and the airflow after graded filtration enters the vacuum pump.

2. The chamber exhaust hole filter used in ALD equipment according to claim 1, characterized in that: The centers of the multiple layers of filter screens are located on the same vertical line, and the intervals between the multiple layers of filter screens are the same, and the intervals are greater than or equal to 20 mm.

3. The chamber exhaust hole filter used in ALD equipment according to claim 1, characterized in that: The multi-layer filter screen includes a first filter screen and a second filter screen, the first filter screen is the layer of filter screen farthest from the inlet of the exhaust pipe, and the second filter screen is the layer of filter screen closest to the inlet of the exhaust pipe. The mesh number of the first filter screen is 80 meshes, and the mesh number of the second filter screen is 30 meshes.

4. The chamber exhaust hole filter used in ALD equipment according to claim 1, characterized in that: The mesh shape of the multi-layer filter is circular, square or diamond.

5. The chamber exhaust hole filter used in ALD equipment according to claim 1, characterized in that: The multi-layer filter screens are all circular in shape, and the diameter of the multi-layer filter screens is the same as the diameter of the air extraction pipe.

6. The chamber exhaust hole filter used in ALD equipment according to claim 2, characterized in that: The multi-layer filter screen is perpendicular to the pipe wall of the air extraction pipe.

7. The chamber exhaust hole filter used in ALD equipment according to claim 1, characterized in that: Two adjacent filter screen layers are connected via a detachable bracket.

8. The chamber exhaust hole filter used in ALD equipment according to claim 7, characterized in that: The detachable bracket is a hollow tube structure, which includes multiple cylindrical segments and an annular groove arranged on the outer surface of the hollow tube structure. The outer surfaces of two adjacent cylindrical segments are connected by the annular groove. The annular groove is recessed along the central axis direction of the hollow tube structure. The annular groove is used to install a sealing ring. The number of the cylindrical segments is the same as the number of layers of the multi-layer filter screen, and a layer of filter screen is installed in each cylindrical segment.

9. The chamber exhaust hole filter used in ALD equipment according to claim 1, characterized in that: The multi-layer filter screens all include a metal ring and a filter screen plate. The filter screen plate is fixed on the inner ring surface of the metal ring. The filter screen plate is composed of a plurality of cross-arranged metal wires.

10. The chamber exhaust hole filter used in ALD equipment according to claim 9, characterized in that: The filter screen plate is a plain weave structure, a twill weave structure or a sintered mesh structure.

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