Vacuum pumping screen mesh device

Abstract

The invention belongs to the technical field of vacuum, and discloses a vacuum pumping screen device which comprises a lower shell, a lower shell, an upper shell and a lower shell, the lower shell is cylindrical and installed at a pumping opening in a vacuum cavity, and a second ventilation opening for ventilation is formed in the side wall of the lower shell; the upper shell is in a barrel shape with a closed upper end, the lower shell is sleeved with the upper shell, and a first ventilation opening used for ventilation is formed in the side wall of the upper shell; the installation pipeline is branched out of a vacuum pipeline where the vacuum pump is connected with the pumping port of the vacuum chamber; one end of the transmission rod penetrates through the lower shell to be fixedly connected with the upper shell, the other end of the transmission rod penetrates out of the mounting pipeline to be connected with the output end of a driving mechanism on the outer side of the vacuum cavity, and the driving mechanism is used for driving the upper shell to move. Therefore, the opening degree of an actual ventilation opening formed by communicating the first ventilation opening and the second ventilation opening is adjusted. The exhaust flow of the vacuum chamber is controlled, the initial load of the vacuum pump can be reduced, and the service life of the vacuum pump is prolonged.

Description

Technical Field

[0001] The invention belongs to the field of vacuum technology, and in particular relates to a vacuum pumping screen device. Background Art

[0002] In the semiconductor manufacturing process, the vacuum environment is very important. The vacuum environment can prevent wafer oxidation and contamination, and ensure chip quality and performance. The vacuum system is usually composed of vacuum pumps, control systems, gas tanks, pipelines and other components, such as Figure 2 In the process, the vacuum pump 200 forms a vacuum environment by pumping the vacuum chamber 100. The vacuum screen can play the following roles in this complex vacuum system:

[0003] In this vacuum system, sometimes due to the nature of the vacuum pump (such as a dry pump), when the vacuum pump stops working unexpectedly, it will cause contaminated particles to flow back into the vacuum chamber 100, causing the chamber that has already reached a vacuum state to be contaminated, which is very likely to cause particle contamination to the silicon wafer.

[0004] Moreover, the working environment inside the deposition equipment chamber is generally a vacuum, and ions will be continuously generated in the chamber due to process requirements. These ions are widely present in the chamber and are used to perform processes such as vapor deposition on the wafers inside the chamber. However, a small amount of ions will also be sucked into the vacuum pump during the vacuum pumping process. When the ions enter the vacuum pump, they will also damage the blades of the vacuum pump, which will greatly reduce the performance and efficiency of the vacuum pump over time.

[0005] Therefore, it is very necessary to design a pumping screen to block the polluted particles in the return gas when the vacuum pump stops suddenly. At present, a pumping screen is installed, such as Figure 1 As shown, the pumping screen mainly includes a cover 10, a support column 20, a filter ring 30, a conductive gasket 40, etc., a plurality of support columns are arranged along the circumferential direction, and the cover is fixed on the top of the support column. A plurality of filter rings are installed at intervals on the support column, and vents are formed between adjacent filter rings between adjacent support columns, and the vacuum pump pumps the vacuum chamber through these vents.

[0006] The pumping screen is designed to be located between the gate valve and the chamber. Its installation position is as follows: Figure 2 As shown. The pumping screen can change the return direction of the pumping port, effectively preventing the return contamination particles from being blown directly onto the silicon wafer. It can also intercept most of the ions and guide the excess charge into the chamber and then transmit it to the ground, which will effectively reduce the damage of the ions to the vacuum pump.

[0007] In addition, the pumping screen can prevent parts from falling into the vacuum pump when maintenance personnel are working. Since the vacuum pump is a very delicate device, the presence of the pumping screen can effectively protect the vacuum pump.

[0008] However, the applicant found that when the vacuum pump is initially started and works at full load, it will cause certain damage to the performance of the vacuum pump. Therefore, if the pumping screen can be used to reduce the initial workload of the vacuum pump, it can effectively protect the vacuum pump. However, the current adjustment of the exhaust port requires opening the chamber to adjust, and the process is complicated, and the exhaust port cannot be automatically adjusted during the process.

[0009] Therefore, it is necessary to improve the pumping screen, which can not only ensure the vacuum state of the vacuum chamber and reduce the entry of ions into the vacuum pump to damage its blades, but also adjust the size of the vent of the pumping screen during the process to protect the vacuum pump. Summary of the invention

[0010]

Technical issues

[0011] In order to solve the problems mentioned above, the purpose of the present invention is to provide a vacuum pumping screen device, which adjusts the size of the actual vent according to the comparison between the detected flow value of the vacuum pipeline and the preset flow value, thereby reliably adjusting the workload of the vacuum pump and protecting the vacuum pump.

[0012]

Technical solution

[0013] The present application provides a vacuum pumping screen device, comprising:

[0014] The lower housing is cylindrical and installed at the pumping port in the vacuum chamber, and has a second vent for ventilation on its side wall;

[0015] The upper shell is in the shape of a cylinder with a closed upper end, and is sleeved on the outer side of the lower shell. The side wall of the upper shell is provided with a first vent for ventilation;

[0016] An installation pipeline is branched from the vacuum pipeline connecting the vacuum pump and the pumping port of the vacuum chamber;

[0017] The transmission rod has one end passing through the lower shell and fixedly connected to the upper shell, and the other end passing through the installation pipeline and connected to the output end of the driving mechanism outside the vacuum chamber.

[0018] The driving mechanism is used to drive the upper shell to move, so as to adjust the opening of the actual vent formed by the first vent and the second vent being connected.

[0019] Optionally, the upper shell is cylindrical, and multiple rows and columns of first vents are formed in the axial and circumferential directions of the upper shell;

[0020] The lower shell is cylindrical, and a plurality of rows and columns of second vents are formed in the axial direction and the circumferential direction of the lower shell.

[0021] Optionally, the first vent of the upper shell overlaps with the second vent of the lower shell in axial position.

[0022] Optionally, the first vent of the upper shell has the same size as the second vent of the lower shell.

[0023] Optionally, the end of the transmission rod passing through the upper shell is fastened with a fastener.

[0024] Optionally, the driving mechanism is a rotary motor, and the other end of the transmission rod is connected to the output shaft of the rotary motor via a coupling.

[0025] Optionally, the transmission rod is installed in the installation pipeline through a magnetic fluid seal.

[0026] Optionally, a flow sensor is also installed on the vacuum pipeline. When the detection value of the flow sensor is greater than a preset flow value, the driving mechanism adjusts the actual air vent of the vacuum pumping screen device to become smaller; when the detection value of the flow sensor is smaller than the preset flow value, the driving mechanism adjusts the actual air vent of the vacuum pumping screen device to become larger.

[0027] Optionally, it also includes a control module, which is connected to the flow sensor and the driving mechanism. When the detection value of the flow sensor is consistent with the preset flow value, the control module sends instructions for process processing; when it is inconsistent, the control module sends instructions to the driving mechanism to adjust the actual opening of the vent.

[0028] Optionally, the lower shell is cylindrical with a closed upper end.

[0029]

Beneficial Effects

[0030] The present application can make corresponding changes to the actual vent through the relative rotation of the upper shell and the lower shell, thereby controlling the exhaust flow rate, which can reduce the initial load of the vacuum pump, reduce the loss of the vacuum pump during operation, and extend the life of the vacuum pump.

[0031] The present application can isolate the vacuum environment from the external environment through the magnetic fluid seal and the transmission part, and the driving mechanism can transmit power to the upper shell in the vacuum chamber in the atmospheric environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a three-dimensional schematic diagram of a pumping screen in the prior art.

[0033] Figure 2 This is a schematic diagram of the vacuum pump return gas.

[0034] Figure 3 It is a three-dimensional schematic diagram of the upper shell of an embodiment of the present application.

[0035] Figure 4 It is a three-dimensional schematic diagram of the lower shell of an embodiment of the present application.

[0036] Figure 5 It is a three-dimensional schematic diagram of an actual vent half-opened according to an embodiment of the present application.

[0037] Figure 6 It is a three-dimensional schematic diagram of the actual vent fully opened in the embodiment of the present application.

[0038] Figure 7 It is a three-dimensional schematic diagram of a transmission rod according to an embodiment of the present application.

[0039] Figure 8 It is a schematic diagram of the installation of the vacuum pumping screen device according to an embodiment of the present application.

[0040] Fig. 9 It is a feedback control flow chart of the vacuum pumping screen device of an embodiment of the present application.

[0041] [Brief Description of Reference Numerals]

[0042] 10: Cover 20: Support column

[0043] 30: filter ring 40: conductive gasket

[0044] 100: Vacuum chamber 200: Vacuum pump

[0045] 210: Flow sensor 300: Upper housing

[0046] 310: first vent 400: lower housing

[0047] 410: Second vent 500: Transmission rod

[0048] 600: Installation pipeline 700: Magnetic fluid seal

[0049] 800: Driving mechanism DETAILED DESCRIPTION

[0050] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the two are connected to each other and the relative position relationship after the connection remains unchanged. The directional terms mentioned in the embodiments of the present application, such as "upper", "lower", "inner side", "outer side", "forward", "backward", etc., are only reference to the directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, 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 therefore cannot be understood as a limitation on the embodiments of the present application.

[0052] Please refer to Figure 2 The vacuum pumping screen device of this embodiment includes an upper shell 300, which is arranged in the vacuum chamber 100, is in the shape of a cylinder with a closed upper end, and has a first vent 310 on its side wall for ventilation; a lower shell 400, which is arranged at the pumping port in the vacuum chamber, is in the shape of a cylinder with a closed upper end, is sleeved in the upper shell 300, and has a second vent 410 on its side wall for ventilation; an installation pipeline 600, which branches out from the vacuum pipeline connecting the vacuum pump 200 and the pumping port of the vacuum chamber; a transmission rod 500, one end of which passes through the lower shell and is fixedly connected to the upper shell 300, and the other end of which passes through the installation pipeline and is connected to the output end of the driving mechanism outside the vacuum chamber.

[0053] The upper shell 300 may be cylindrical, with a closed upper end and an open lower end, and one or more first vents 310 are arranged on its side wall. Each first vent 310 may be a hole arranged on the side wall of the upper shell 300. Exemplarily, each first vent 310 may be a long strip extending in the circumferential direction, and a plurality of long strip first vents 310 may be arranged at intervals along the axial direction of the upper shell to form a hole array, and a plurality of such hole arrays may be arranged at intervals in the circumferential direction, thereby forming multiple rows and columns of first vents 310 in the axial and circumferential directions. However, this embodiment does not exclude the possibility of having only one hole array, or even only one first vent 310.

[0054] The lower shell 400 may be cylindrical, with a closed upper end and an open lower end, and one or more second vents 410 are arranged on its side wall. Each second vent 410 may be a hole arranged on the side wall of the lower shell 400. Exemplarily, each second vent 410 may be a long strip extending in the circumferential direction, or may be a plurality of long strip second vents 410 arranged at intervals in the axial direction to form a hole array, and a plurality of such hole arrays are arranged at intervals in the circumferential direction, thereby forming multiple rows and columns of second vents 410 in the axial and circumferential directions. However, this embodiment does not exclude the possibility of having only one hole array, or even only one second vent 410.

[0055] However, the present application does not exclude that the upper end of the lower shell 400 may not be closed, but the upper end of the lower shell is sealed after the upper shell 300 and the lower shell 400 are assembled. The specific structure is not described here.

[0056] The upper shell is buckled on the lower shell through its lower opening, or it can be said that the lower shell is sleeved in the upper shell 300 and is rotatably sleeved in the upper shell 300. The first vent 310 of the upper shell 300 overlaps with the second vent 410 of the lower shell 400 along the axial position. Specifically, for example, if the upper shell 300 and the lower shell 400 are vertically arranged (i.e., the axis is vertical), the first vent 310 and the second vent 410 are at the same height in the vertical direction.

[0057] The size of the first vent 310 of the upper shell 300 and the second vent 410 of the lower shell 400 can be the same. For example, if the size of the first vent 310 is 10cm x 2cm, the size of the second vent 410 is also 10cm x 2cm. In this way, when the upper shell 300 rotates, its first vent 310 and the second vent can be completely disconnected, partially connected, or completely connected. The actual gas channel formed by the connection between the first vent and the second vent is called the actual vent. If it is completely disconnected, the connection between the vacuum pump and the vacuum chamber is completely closed, that is, the actual vent is the smallest; if it is partially connected, the vacuum pump and the vacuum chamber are in a partially connected state, and the actual vent is between the maximum and the minimum; if it is fully connected, the vacuum pump and the vacuum chamber are in a maximum connected state, and the actual vent is the largest at this time.

[0058] Of course, the sizes of the first vent 310 and the second vent 410 may also be different, for example, the length of the first vent 310 is greater than the length of the second vent 410, and the distance between the second vents 410 in the circumferential direction is greater than the length of the first vent 310. Exemplarily, the size of the first vent 310 is 10cm x 2cm, and the size of the second vent 410 is 8cm x 2cm. Moreover, if the distance between the second vents 410 in the circumferential direction is greater than 10cm, then by rotating the upper shell 300, the first vent 310 completely covers the second vent 410, and the vacuum pump and the vacuum chamber are in the maximum communication state, and the actual vent is the largest at this time; the first vent 310 and the second vent 410 do not overlap at all, then the communication between the vacuum pump and the vacuum chamber is closed, and the actual vent is the smallest at this time.

[0059] like Figure 4 The first vent 310 covers half of the second vent 410, that is, the actual vent is half open. Figure 5 This is a state where the first vent 310 and the second vent 410 are completely connected, and the actual vent is at the maximum state.

[0060] One end of the transmission rod 500 has a thread, which can pass through the lower shell 400 and the upper shell 300 in sequence, and is fastened with a nut at the end of the transmission rod 500 passing through the upper shell 300, so as to fix the upper shell 300 with the transmission rod 500. Of course, the threaded connection is only exemplary, and the present application does not exclude the possibility of connection by other means such as welding, riveting, etc.

[0061] A mounting pipeline 600 is branched out from the vacuum pipeline connecting the vacuum pump 200 and the vacuum chamber 100, and the other end of the transmission rod 500 passes through the mounting pipeline 600 and is connected to the output end of the driving mechanism 800. The driving mechanism 800 can be a rotary motor, and the other end of the transmission rod 500 can be connected to the output shaft of the rotary motor through a key connection, or of course, can be connected to the output shaft of the rotary motor through a coupling. Alternatively, the rotary mechanism can also be connected to a reducer through a rotary motor, and the reducer is then connected to the other end of the transmission rod 500 through a coupling.

[0062] The driving mechanism drives the transmission rod 500 to rotate, thereby controlling the relative position of the first vent 310 of the upper shell and the second vent 410 of the lower shell, thereby controlling the connection state of the first vent 310 and the second vent 410, and achieving the purpose of adjusting the flow of the vacuum pump. The flow rate of the gas in the cavity is adjusted when passing through the vent and then reaches the vacuum pump below, which can reduce the initial load of the vacuum pump, reduce the loss of the vacuum pump during operation, and extend the life of the vacuum pump.

[0063] Specifically, when the vacuum pump is initially started, the driving mechanism drives the transmission rod 500 to rotate, so that the first vent 310 covers a portion of the second vent 410, thereby reducing the flow of the vacuum pump, thereby reducing the initial workload of the vacuum pump, and thus effectively protecting the vacuum pump. Then, the area connected between the first vent 310 and the second vent 410 can be gradually adjusted to become larger, that is, the actual vent becomes larger, thereby gradually increasing the flow of the vacuum pump.

[0064] Furthermore, the transmission rod 500 is installed in the installation pipeline 600 through the magnetic fluid seal 700. The magnetic fluid seal and the transmission part can isolate the vacuum environment from the external environment, so that the rotating motor can transmit power to the upper housing in the vacuum chamber in the atmospheric environment. When the magnetic fluid is injected into the gap of the magnetic field, it can fill the entire gap, forming a "liquid O-ring" to form a reliable dynamic seal.

[0065] When the rotating motor rotates, the rotation amplitude is transmitted to the transmission rod 500 through the magnetic fluid seal 700, thereby driving the upper shell 300 to rotate. The relative rotation of the upper shell 300 and the lower shell 400 can cause the actual vent to produce corresponding changes, thereby controlling the exhaust flow rate. The gas in the cavity is adjusted when passing through the exhaust port and then reaches the vacuum pump 200 below. This can reduce the initial load of the vacuum pump 200, reduce the loss of the vacuum pump during operation, and extend the life of the vacuum pump. The magnetic fluid seal and transmission part can isolate the vacuum environment from the external environment, allowing the drive mechanism to transmit power to the upper shell 300 in the vacuum chamber 100 in the atmospheric environment.

[0066] It should be noted that the above is to adjust the connection state of the first vent 310 and the second vent 410 by relative rotation of the upper shell and the lower shell. The present application is not limited to adjustment by rotation only, and can also be adjusted by linear motion. For example, the upper shell is connected to a linear motor or other linear drive mechanism, and the upper shell and the lower shell can move relative to each other along the axial direction, so as to adjust the connection state of the first vent 310 and the second vent 410. The specific content will not be described in detail here. The following is only taken as an example that the drive mechanism is a rotating motor.

[0067] In some embodiments, a flow sensor 210 is also installed on the vacuum pipeline. The flow sensor 210 on the vacuum pipeline can detect the flow rate of the vacuum pump. The detection value of the flow sensor is compared with the preset flow value so that the drive mechanism can be regulated. Taking the rotary motor as an example, when the flow in the vacuum pipeline is larger than the preset flow value, the rotary motor is rotated in the opposite direction by one step through negative feedback regulation, and the actual air vent of the vacuum pumping screen device is adjusted to be smaller, so that the flow rate gradually decreases. When the detection value of the flow sensor is smaller than the preset flow value, it is adjusted in the opposite direction, and the rotary motor is rotated forward by one step, and the actual air vent of the vacuum pumping screen device becomes larger, so that the flow rate gradually increases.

[0068] It may also include a control module, which is connected to the flow sensor 210 and the driving mechanism. Fig. 9 This is a feedback control flow chart of the vacuum pumping screen device of the embodiment of the present application, and the following reference is made to Fig. 9 To illustrate its feedback control process. The control module reads the preset flow value X, and reads the flow value Y of the flow sensor 210 in real time, and compares the preset flow value X with the flow value Y of the flow sensor 210. If they are consistent, normal process processing is performed. If they are inconsistent, the size of X and Y is further determined. If X is greater than Y, the rotating motor rotates forward one step, thereby driving the upper shell to rotate so that the overlapping part of the first vent 310 and the second vent 410 increases, so that the actual vent increases, thereby increasing the flow of the vacuum pump. If X is less than Y, the rotating motor reverses one step, thereby driving the upper shell to rotate so that the overlapping part of the first vent 310 and the second vent 410 decreases, so that the actual vent decreases, thereby reducing the flow of the vacuum pump.

[0069] In some embodiments, since the actual mechanical transmission is not in an ideal state, the errors that may occur in the actual adjustment process can be analyzed and measures can be taken. The processes that may cause errors include:

[0070] (1) The error between the actual rotation amount and the ideal rotation amount after the rotating motor receives the rotation signal;

[0071] (2) The error between the actual transmission amount and the ideal transmission amount of the transmission rod after the rotating motor rotates;

[0072] (3) The error between the actual relative rotation of the upper shell and the lower shell and the ideal rotation.

[0073] Since the transmission rod and the upper and lower shells are inside a high vacuum chamber, it is difficult to reduce the error by directly measuring the rotation / transmission amount. A sensor (such as a grating disk) for detecting the rotation amount can be set at the rotating motor to control the rotating motor through feedback to reduce the rotation amount error.

[0074] The transmission rod should reduce the error caused by rotational deflection and airflow disturbance as much as possible. For example, the selection of rigid materials and surface treatment can reduce the impact of rotational deflection and airflow disturbance.

[0075] The friction caused by the relative rotation of the upper and lower shells and the errors caused by airflow disturbance should be reduced as much as possible. For example, the processing accuracy of the relative friction points should be high, and the friction area between the upper and lower shells should be reduced as much as possible.

[0076] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and deformations according to the present invention, but these corresponding changes and deformations shall fall within the protection scope of the claims of the present invention.

Claims

1. A vacuum pumping screen device, characterized in that: include: The lower housing is cylindrical and installed at the pumping port in the vacuum chamber, and has a second vent for ventilation on its side wall; The upper shell is in the shape of a cylinder with a closed upper end, and is sleeved on the outer side of the lower shell. A first vent for ventilation is provided on the side wall of the upper shell; An installation pipeline is branched from the vacuum pipeline connecting the vacuum pump and the pumping port of the vacuum chamber; The transmission rod has one end passing through the lower shell and fixedly connected to the upper shell, and the other end passing through the installation pipeline and connected to the output end of the driving mechanism outside the vacuum chamber. The driving mechanism is used to drive the upper shell to move, so as to adjust the opening of the actual vent formed by the first vent and the second vent being connected.

2. The vacuum pumping screen device according to claim 1, characterized in that: The upper shell is cylindrical, and a plurality of rows and columns of first vents are formed in the axial and circumferential directions of the upper shell; The lower shell is cylindrical, and a plurality of rows and columns of second vents are formed in the axial direction and the circumferential direction of the lower shell.

3. The vacuum pumping screen device according to claim 1, characterized in that: The first vent of the upper shell overlaps with the second vent of the lower shell in the axial direction.

4. The vacuum pumping screen device according to claim 3, characterized in that: The first vent of the upper shell has the same size as the second vent of the lower shell.

5. The vacuum pumping screen device according to claim 1, characterized in that: The end of the transmission rod passing through the upper shell is fastened by a fastener.

6. The vacuum pumping screen device according to claim 1, characterized in that: The driving mechanism is a rotating motor, and the other end of the transmission rod is connected to the output shaft of the rotating motor through a coupling.

7. The vacuum pumping screen device according to claim 1, characterized in that: The transmission rod is installed in the installation pipeline through a magnetic fluid seal.

8. The vacuum pumping screen device according to claim 1, characterized in that: A flow sensor is also installed on the vacuum pipeline. When the detection value of the flow sensor is larger than the preset flow value, the driving mechanism adjusts the actual air vent of the vacuum pumping screen device to become smaller; when the detection value of the flow sensor is smaller than the preset flow value, the driving mechanism adjusts the actual air vent of the vacuum pumping screen device to become larger.

9. The vacuum pumping screen device according to claim 8, characterized in that: It also includes a control module, which is connected to the flow sensor and the drive mechanism. When the detection value of the flow sensor is consistent with the preset flow value, the control module sends instructions for process processing; when it is inconsistent, the control module sends instructions to the drive mechanism to adjust the actual opening of the vent.

10. The vacuum pumping screen device according to claim 1, characterized in that: The lower shell is in the shape of a cylinder with a closed upper end.

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