Gas purification device and piping system for process chamber

Abstract

The application relates to a gas purification device and a pipeline system for a process cavity. The gas purification device comprises a shell with a pipeline cavity; a filter structure arranged in the pipeline cavity, the filter structure comprising a plurality of filter pieces with both ends penetrating through and filter cores arranged in the filter pieces, the outer diameter and the inner diameter of the filter pieces gradually decrease from the first end to the second end, the axes of all the filter pieces are parallel to the axis of the pipeline cavity, the first end of each filter piece is located at the same end side of the pipeline cavity, the second ends of the filter pieces form a gas path buffer zone, all the filter pieces jointly form a gas passage in the shell, and when gas enters the pipeline cavity from the second end of the filter piece to the first end of the filter piece, part of the gas contacts the outer surface of the filter piece through the gas path buffer zone. According to the application, backflow gas carrying particle pollutants can be prevented from flowing into the process cavity to contaminate wafers and affect product quality.

Description

Technical Field

[0001] This application relates to the field of semiconductor process gas treatment technology, specifically to a gas purification device and a piping system for a process chamber. Background Technology

[0002] Semiconductor manufacturing processes typically require highly clean environments, often involving vacuum conditions. This necessitates complex gas delivery and exhaust systems, such as exhaust lines for process chambers and pump lines for vacuum pumps. Within these systems, flowing gases may carry fine particles from reaction byproducts, equipment wear, or externally introduced contaminants. If these particles are carried into the vacuum pump or flow back into the process chamber, they can contaminate critical components such as wafers and photomasks, leading to increased defect rates, decreased yields, and potentially shortened lifespans of core equipment like vacuum pumps.

[0003] To address the aforementioned issues, gas filtration devices must be installed in the exhaust passage or pump pipeline. Traditional gas filtration devices primarily employ multi-layer filter structures or roller-type slit structures to adsorb and purify the gas. However, when the pressure difference in the exhaust passage or pump pipeline is too large, such as during a momentary system depressurization, backflow gas is easily generated, meaning gas flows backward into the process chamber. These traditional gas filtration devices mainly target forward airflow (i.e., from inside the chamber to the outside) and cannot purify backflow gas. This results in backflow gas carrying a large amount of particulate contaminants that directly impact and contaminate the wafers inside the chamber, leading to batch defects and significant economic losses.

[0004] Therefore, a new gas filtration device is needed that can limit particulate contaminants in the filtered return gas. Summary of the Invention

[0005] The technical problem to be solved by this application is to provide a gas purification device and a piping system for the process chamber, which can prevent the return gas from carrying particulate contaminants into the process chamber and contaminating the wafer, thus affecting product quality.

[0006] According to a first aspect of the embodiments of this application, a gas purification device is provided, comprising: The shell has a tubular cavity; A filter structure is disposed within the pipe cavity. The filter structure includes multiple filter elements with both ends extending through it and filter cartridges disposed within the filter elements. The outer diameter and inner diameter of the filter elements both decrease from the first end to the second end. The axes of all filter elements are parallel to the axis of the pipe cavity, and the first ends of each filter element are located on the same end side of the pipe cavity. The gap between the second ends of each filter element forms an air passage buffer, so that all filter elements together form a gas channel within the housing. When gas enters the pipe cavity and flows from the second end of the filter element to the first end of the filter element, part of the gas contacts the outer surface of the filter element through the air passage buffer, and part of the gas enters the filter element and is filtered by the filter cartridge.

[0007] In one embodiment, the outer surface of the filter element is a smooth surface.

[0008] In one embodiment, the first end of the filter element is flush with one end of the housing, and the second end of the filter element is at a predetermined distance from the other end of the housing.

[0009] In one embodiment, a filter screen is provided in the duct cavity between the second end of the filter element and the other end of the housing.

[0010] In one embodiment, the filter element is located at the second end of the filter element.

[0011] In one embodiment, the housing is provided with multiple layers of the filter structure, each layer of the filter structure is arranged sequentially along the axis of the pipe cavity, and the axes of the filter elements in adjacent layers are staggered.

[0012] In one embodiment, the gas purification device includes a plurality of housings connected in series, each housing having a filter structure therein, and the filter elements in adjacent housings being staggered.

[0013] In one embodiment, the housing is a tapered tube.

[0014] In one embodiment, the gas channels in different layers have different flow cross-sectional dimensions, and the flow cross-section of the gas channels gradually decreases from one end of the gas purification device to the other end of the gas purification device.

[0015] According to a second aspect of the present application, a piping system for a process chamber is provided, comprising: a gas pipe with an opening valve, a gas purification device as described in any of the preceding claims, wherein the gas purification device is connected to the gas pipe, and a first end of the filter element is disposed near the side of the gas pipe connected to the process chamber.

[0016] Compared with the prior art, the beneficial effects of this application are as follows: By installing multiple filters within the pipeline cavity, with both the outer and inner diameters of the filters gradually decreasing from the first end to the second end, the flow resistance (pressure drop) generated by the forward airflow from the first end to the second end is significantly lower than the flow resistance generated by the reverse airflow from the second end to the first end. This characteristic allows the device to effectively suppress and mitigate the occurrence of reverse backflow while ensuring smooth process exhaust. Furthermore, when backflow is unavoidable, the gas path buffer can adsorb and intercept contaminant particles in the backflow gas. In other words, the outer surface of the filter can guide and block contaminant particles, thereby purifying the backflow gas and preventing contaminant particles from flowing into the process cavity with the backflow gas and contaminating the wafer, thus affecting product quality. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a gas purification device according to an exemplary embodiment; Figure 2 This is a schematic diagram illustrating a filter element according to an exemplary embodiment; Figure 3 This is a schematic diagram of a gas purification device according to another exemplary embodiment; Figure 4 This is a top view of a gas purification device according to another exemplary embodiment; Figure 5 This is a schematic diagram of a gas purification device according to another exemplary embodiment.

[0018] In the picture, 1. Shell; 2. Filter element; 3. Filter cartridge; 100. Pipe cavity. Detailed Implementation

[0019] Unless otherwise defined, the technical or scientific terms used in this specification and claims shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. Specific embodiments of this application will be described below in conjunction with the accompanying drawings. It should be noted that, in order to provide a concise description, this specification cannot exhaustively describe all features of the actual embodiments. Without departing from the spirit and scope of this application, those skilled in the art can modify and substitute the embodiments of this application, and the resulting embodiments are also within the protection scope of this application.

[0020] This application provides a gas purification device that allows for a stable outflow of forward airflow, suppresses reverse airflow, and purifies reverse airflow. (Reference) Figure 1 In one specific embodiment, the gas purification device includes: The housing 1 has a pipe cavity 100; A filtration structure is disposed within the pipe cavity 100. The filtration structure includes multiple filter elements 2 that extend through both ends and filter cartridges 3 disposed within the filter elements 2. See Figure 2 As shown, the outer and inner diameters of the filter element 2 decrease from the first end to the second end. The axes of all filter elements 2 are parallel to the axis of the pipe cavity 100, and the first ends of all filter elements 2 are located on the same end side of the pipe cavity 100. The gaps between the second ends of each filter element 2 form a gas path buffer zone, so that all filter elements 2 together form a gas channel within the housing 1. When gas enters the pipe cavity 100, it flows from the second end of the filter element 2 to the first end of the filter element (see...). Figure 1 When the direction of the dashed arrow is in the middle, part of the gas comes into contact with the outer surface of the filter element 2 through the gas path buffer, and part of the gas enters the filter element 2 and is filtered by the filter element 3.

[0021] This application achieves bidirectional airflow and purification through the arrangement of filter element 2, and reduces the flow rate of gas flowing from the second end of filter element 2 to the first end of filter element 2 (i.e., reverse airflow). The gas flow process is as follows: Forward airflow (such as process exhaust gas discharged from the process chamber) see Figure 1 The solid arrows indicate that the gas enters from the first end of each filter element 2. Each filter element 2 has a tapered arc structure design with smooth and flat curved surfaces on both its inner and outer surfaces. The overall flow is smooth, and the airflow is guided and accelerated within it, resulting in minimal pressure loss. The gas is then discharged from the second end of the filter element 2. The flow resistance of this gas channel to the forward airflow is controllable, facilitating circulation. Reverse airflow (such as recirculated gas) see Figure 1 The direction of the dashed arrow indicates that when backflow or reverse flow occurs, the polluted gas first enters the aforementioned airflow buffer zone. Filter element 2 can be used as a flow obstructor, allowing the polluted gas to fully contact the outer surface of filter element 2, thereby generating a huge local vortex and kinetic energy loss, forming extremely high local flow resistance, reducing the airflow into filter element 2, that is, reducing the amount of polluted gas passing through the device. In addition, the outer surface of filter element 2 can guide and intercept particles in the polluted gas. At the same time, the polluted gas entering filter element 2 can be filtered by the filter element 3 set inside filter element 2, realizing multi-stage purification of reverse airflow. The filter element can also generate flow resistance for polluted gas. Furthermore, as the reverse airflow flows from the second end to the first end of filter element 2, the flow path suddenly enters a large space from a narrow flow channel (the inner diameter of the filter element increases from the second end to the first end), and the flow velocity drops sharply. Some particles will be unable to follow the flow due to inertia and will be deposited on the inner wall surface of filter element 2, further improving the purification effect on reverse airflow.

[0022] Specifically, each filter element 2 can be understood as multiple holes within the housing, meaning they are directly machined during the housing formation process. The diameter of these holes gradually decreases from the first end to the second end, such as a conical hole. Alternatively, the diameter of the holes may initially remain constant or gradually increase before gradually decreasing, such as a combination of cylindrical and conical holes. In other words, the inner diameter of the filter element 2 only needs to satisfy the condition that the inner diameter of the first end is greater than the inner diameter of the second end; the variation from the first end to the second end is not limited. To better create an airflow buffer zone between the filter elements 2, gaps can be incorporated during the machining of each filter element 2 within the housing. This means that the second ends of each filter element 2 are machined discretely, and the outer diameter of each filter element 2 increases from the second end to the first end. Therefore, the gaps between adjacent filter elements 2 vary along the airflow path and are not constant. This gap design can improve the flow resistance to reverse airflow.

[0023] Each filter element 2 can be independently manufactured and then fixed inside the housing by welding or other processes. During fixing, the first ends of each filter element 2 are located on the same side, and the second ends of each filter element 2 are located on the other side. The inner diameter, length, and other dimensions of each filter element 2 can be the same or different, and can be designed according to the flow resistance requirements of bidirectional airflow.

[0024] The filter element described above can adopt a traditional filter element structure, such as a slit or mesh structure, and is not limited here. Specifically, the filter element is located at the second end of the filter element 2, so that the reverse airflow passing through the air path buffer is guided by the outer surface of the filter element and filtered by the filter element at the second end of the filter element, thus timely suppressing the flow of pollutant particles with the reverse airflow.

[0025] In one embodiment, the outer surface of the filter element 2 is a smooth surface, which makes it easier for the reverse airflow to adsorb pollutant particles when it comes into contact with the filter element 2, thereby improving the purification capacity.

[0026] like Figure 1 As shown, the first end of the filter element 2 is flush with one end of the housing 1, and the second end of the filter element 2 is at a preset distance from the other end of the housing 1. The preset distance can be designed according to the flow resistance requirements of the reverse airflow. In addition, the preset distance can create a larger space in the other end of the housing 1, making it easier for the forward airflow to diffuse after passing through the second end of the filter element 2. This allows the reverse airflow to first enter the larger space and disperse into the air path buffer zone and then enter the filter element 2 through the second end of the filter element 2, thereby increasing the suppression of the reverse airflow.

[0027] In one embodiment of achieving multi-stage purification and inhibition, such as Figure 3As shown, the housing 1 contains a multi-layered filtration structure, with each layer arranged sequentially along the axis of the pipe cavity. The filter elements 2 within adjacent layers are staggered, specifically meaning the axes of the filter elements 2 are staggered, resulting in a curved airflow path formed by the filter elements in each layer. This embodiment achieves multi-stage purification through a multi-layered filtration structure. The staggered distribution of the filter elements 2 within adjacent layers, as shown... Figure 4 As shown, the filter elements in the first-stage filtration structure are represented by solid lines, while those in the second-stage filtration structure are represented by dashed lines. The solid and dashed filter elements are staggered, which can be understood as the axes of the two filter elements not coinciding, i.e., not on the same straight line. This allows for multi-stage suppression and purification of the reverse airflow, enhancing the interlayer reverse filtration effect and reducing the possibility of the reverse airflow carrying polluting particles that contaminate the process.

[0028] Another embodiment of achieving multi-stage purification and inhibition, Figure 5 As shown, the gas purification device described above includes multiple interconnected housings 1, each housing 1 containing the aforementioned filter structure, with the filter elements 2 in adjacent housings staggered. The gas purification device in this embodiment is a modular design, with each filter layer fabricated separately and connected by fixing the housings together. This embodiment provides multi-stage purification for the reverse airflow, with the filter elements 2 in adjacent housings staggered, as shown in the diagram. Figure 4 As shown, it can be understood that the axes of filter elements 2 in different shells do not coincide. This can increase the flow resistance to the reverse airflow, reduce the reverse airflow throughput, and at the same time improve the purification of the reverse airflow and reduce the throughput of pollutant particles.

[0029] like Figure 3 , Figure 5 As shown, the flow cross-section (i.e., the sum of the inner cross-sections of all filter elements in each layer) of the gas channels in different layers is different, and the flow cross-section of the gas channels gradually decreases from one end of the gas purification device to the other end. The gradient setting of the flow cross-section of the gas channels means that the inner diameters of the filter elements in different layers are different. For example, the inner diameter of the filter elements in each layer can change such that it increases along the reverse airflow direction and decreases along the forward airflow direction, which can further reduce the throughput of the reverse airflow and improve the purification capacity for the reverse airflow.

[0030] Specifically, the aforementioned shell can be a tapered tube, thereby gradually reducing the cross-sectional area of ​​the pipe cavity, which in turn gradually reduces the flow cross-section of the gas passage. In addition, since the shell is a tapered tube and is placed inside the gas path, when the airflow (i.e., the reverse airflow) flows from the small-diameter end of the shell to the large-diameter end, part of the reverse airflow will come into contact with the outer surface of the shell. In this way, pollutant particles in the airflow can be deposited on the outer surface of the shell, further purifying the reverse airflow.

[0031] See Figure 5As shown, a filter screen 4 is provided in the duct cavity between the second end of the filter element 2 and the other end of the housing 1. Understandably, in a multi-layer filtration structure, there can be multiple filter screens 4, i.e., one screen is provided in each layer, or the filter screen 4 is only provided in the port of the housing that serves as the inlet for the reverse airflow. The filter screen 4 further intercepts pollutant particles in the reverse airflow, achieving primary purification of the reverse airflow, allowing each layer of the filtration structure to act as secondary purification of the reverse airflow, thus improving the purification capacity.

[0032] According to a second aspect of the embodiments of this application, a pipeline system (not shown) is provided, comprising: a gas pipe equipped with an opening valve, and a gas purification device as described in any of the preceding claims, wherein the gas purification device is connected to the gas pipe, and the first end of the filter element is disposed near the side of the gas pipe connected to the process chamber. This pipeline system is applicable to the exhaust system of a process chamber and a vacuum pump pipeline system. For example, it can be used as an exhaust pipe connected to the process chamber. The opening valve can control the opening and closing of the gas pipe and adjust the flow rate of the gas pipe. Process waste gas in the process chamber can be discharged through the gas purification device and the gas pipe. In use, the first end of the filter element is disposed near the process chamber side, i.e., the direction from the first end to the second end of the filter element is the forward conduction direction, serving as the normal exhaust direction for process waste gas, while the direction from the second end to the first end of the filter element is the return flow direction, thereby achieving the blocking and purification of the return gas. When contamination occurs in the reflux direction due to uncontrollable factors, such as a momentary loss of system pressure, excessive pressure difference in the gas pipe can cause reflux gas. The gas purification device suppresses and purifies the reflux gas. That is, the reflux gas enters the housing from the second end of the housing (i.e., flows from the second end side of the filter to the first end side), and is guided by the outer surface of the filter 2 through the gas path buffer zone, and is also guided and filtered by the axially distributed multi-level filter elements. This can prevent contaminant particles from flowing into the process chamber with the reflux gas and contaminating the wafer, thus affecting product quality.

[0033] Specifically, the gas purification device can be installed in the gas path near the process chamber, with the first end of each filter element closer to the process chamber than its second end. See Figure 3 , Figure 5As shown, the gas purification device has a three-layer filtration structure, meaning it has three layers of filter elements, and the inner diameters of the filter elements in different layers can be different. Process waste gas from the process chamber enters the gas path, passes through the gas purification device, and is then discharged normally. When the system experiences instantaneous pressure loss, and backflow occurs in the piping system of this embodiment, the contaminated gas first collides with the housing 1 in the gas pipe. If it contacts the outer surface of the conical housing, it undergoes primary filtration. The conical shape of housing 1, with its smaller diameter end, suppresses the backflow gas, allowing some of the backflow gas to enter the housing 1. Each filter element 2 can act as a flow obstructor. Furthermore, the staggered distribution of each filter element 2 causes the airflow to bend, ensuring sufficient contact between the contaminated gas and the outer surface of the filter element 2, and creating extremely high flow resistance, reducing the amount of backflow gas passing through. Simultaneously, the inner and outer surfaces of each filter element 2 can deposit contaminant particles from the backflow gas, achieving multi-stage purification of the backflow gas. This suppresses the backflow gas from flowing into the process chamber. Even if a small amount flows in, the contaminant particles in the backflow gas have already been purified by the gas purification device, preventing contamination of the wafers in the process chamber. Even better, the gas purification device is positioned close to the process chamber, such as at the port where the gas path connects to the process chamber, or at a certain distance from the port. It can be positioned according to the location where the backflow gas is generated, so as to better avoid backflow gas contaminating the wafers in the process chamber.

[0034] The above description of the embodiments is intended to enable those skilled in the art to understand and apply this application. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without creative effort. Therefore, this application is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope and spirit of this application are within the scope of this application.

Claims

1. A gas purification device, comprising: The shell has a tubular cavity; A filter structure is disposed within the pipe cavity. The filter structure includes multiple filter elements with both ends extending through it and filter cartridges disposed within the filter elements. The outer diameter and inner diameter of the filter elements both decrease from the first end to the second end. The axes of all filter elements are parallel to the axis of the pipe cavity, and the first ends of each filter element are located on the same end side of the pipe cavity. The gap between the second ends of each filter element forms an air passage buffer, so that all filter elements together form a gas channel within the housing. When gas enters the pipe cavity and flows from the second end of the filter element to the first end of the filter element, part of the gas contacts the outer surface of the filter element through the air passage buffer, and part of the gas enters the filter element and is filtered by the filter cartridge.

2. The gas purification device as described in claim 1, characterized in that, The outer surface of the filter element is a smooth surface.

3. The gas purification device as described in claim 1, characterized in that, The first end of the filter element is flush with one end of the housing, and the second end of the filter element is at a predetermined distance from the other end of the housing.

4. The gas purification device as described in claim 3, characterized in that, A filter screen is provided in the duct cavity between the second end of the filter element and the other end of the housing.

5. The gas purification device as described in claim 1, characterized in that, The filter element is located at the second end of the filter element.

6. The gas purification device as described in claim 1, characterized in that, The housing is provided with multiple layers of the filter structure, and each layer of the filter structure is arranged sequentially along the axis of the pipe cavity, with the axes of the filter elements in adjacent layers being staggered.

7. The gas purification device as described in claim 1, characterized in that, The gas purification device includes multiple housings connected in series, each housing having a filter structure, and the filter elements in adjacent housings are staggered.

8. The gas purification device according to any one of claims 5-7, characterized in that, The shell is a tapered tube.

9. The gas purification device according to any one of claims 5-7, characterized in that, The cross-sectional dimensions of the gas channels in different layers are different, and the cross-sectional dimensions of the gas channels gradually decrease from one end of the gas purification device to the other end.

10. A piping system for a process cavity, characterized in that, include: The gas pipe is equipped with an opening valve, and the gas purification device as described in any one of claims 1 to 9 is connected to the gas pipe, wherein the first end of the filter element is disposed near the side of the gas pipe connected to the process chamber.

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