High-purity helium pipeline gas evacuation and replacement method and system for semiconductor equipment

Abstract

The invention discloses a high-purity helium pipeline gas evacuation and replacement method and system for semiconductor equipment, and the method comprises the steps: carrying out the evacuation of a to-be-purified helium pipeline to a first preset value through a dry-type evacuation pump, then filling the to-be-purified helium pipeline with high-purity nitrogen, and increasing the pressure to a second preset value; vacuumizing the to-be-purified helium pipeline to a first preset value through the dry vacuumizing pump again; the to-be-purified helium pipeline is further evacuated through the low-temperature pump unit, so that the helium pipeline is in a high-vacuum state; and high-purity helium is introduced into the helium pipeline until the required gas pressure is reached. The low-temperature pump unit is matched with the dry-type evacuation pump, so that the ultimate vacuum degree is greatly improved, the helium pipeline is repeatedly filled with nitrogen and evacuated, evacuation flow washing is achieved, helium consumption is greatly reduced, and the device has the advantages of being easy and convenient to operate and high in production efficiency.

Description

Technical Field

[0001] The present invention relates to the field of low-temperature refrigeration technology, and in particular to a method and system for evacuating and replacing gas in a high-purity helium pipeline for semiconductor equipment. Background Art

[0002] With the development and application of cryogenic technology, cryogenic pump systems have also been widely used in the semiconductor industry and the medical industry. Helium pipelines are important gas pipelines connecting refrigerators and compressors, and the purity of helium in helium pipelines is crucial. Impurities in the helium system may solidify or deposit at low temperatures, causing abnormal operation of the refrigerator, which may cause the cryopump to fail to reach the required low temperature state, thereby reducing its pumping capacity and work efficiency. For example, some moisture or other impurity gases will condense at extremely low temperatures. When impurity gases and moisture condense on the refrigerator piston, it will cause the piston movement to stagnate. In severe cases, the refrigerator will make abnormal noises and fail to reach the target temperature, affecting the life of the refrigerator.

[0003] The existing helium pipeline evacuation and replacement technologies mainly include the following:

[0004] 1. Dry vacuum system

[0005] Working principle: Use a dry vacuum pump, such as a double-sided oil-free vortex vacuum pump, to extract the gas in the pipeline through mechanical movement to reduce the pressure in the pipeline. After reaching the target vacuum degree, fill it with helium at a certain pressure for replacement, and then evacuate the air. Repeat this process to achieve the purity requirement.

[0006] Features: The system is relatively simple and has no risk of oil contamination; however, the pumping capacity is limited, and the vacuum replacement time is relatively long. It is difficult for a low-power dry vacuum pump to reach the target vacuum degree, and the production efficiency is low. During the production process, helium needs to be used for inflation and vacuum replacement many times to achieve 99.999% purity inside the pipeline. During this period, a large amount of helium is used, and the economic benefits are poor. In addition, according to a large number of engineering experiences, it is found that after the dry vacuum pump evacuates the helium pipeline and remains stationary for a period of time, the purity of the helium in the pipeline decreases when tested with a purity meter.

[0007] 2. Oil vacuum device

[0008] Working principle: The oil vacuum device consists of an oil vacuum pump and a buffer tank. When the oil vacuum pump is working, the gas in the pipeline is pumped out. The gas first enters the buffer tank and then is discharged through the pipeline. Features: Thanks to the participation of the oil pump, the gas extraction capacity has been greatly improved, and the vacuum replacement time has been shortened, but the disadvantages are also obvious. Although a buffer tank is arranged, there is still a risk of oil return, which is unacceptable for high-purity helium transmission pipelines used in semiconductor equipment.

[0009] Therefore, the existing high-purity helium pipeline evacuation and purification method has problems such as long evacuation operation time, substandard pipeline evacuation vacuum, and oil return pollution during oil pump evacuation, which seriously affect production efficiency and product quality. Summary of the invention

[0010] In order to solve the technical problems existing in the background technology, the present invention provides a method and system for evacuating and replacing gas in a high-purity helium pipeline for semiconductor equipment.

[0011] The present invention provides a method for evacuating and replacing high-purity helium pipeline gas for semiconductor equipment, comprising the following steps:

[0012] S1. evacuating the helium pipeline to be purified by a dry evacuation pump until the pressure in the helium pipeline drops to a first preset value and is maintained, and then filling the helium pipeline to be purified with high-purity nitrogen until the pressure in the helium pipeline rises to a second preset value and is maintained;

[0013] S2, evacuating the helium pipeline to be purified again by using a dry evacuation pump until the pressure in the helium pipeline drops to a first preset value;

[0014] S3, further evacuating the helium pipeline to be purified by using a cryopump unit until the pressure in the helium pipeline drops to a third preset value and is maintained, so that the helium pipeline is in a high vacuum state;

[0015] S4. Introduce high-purity helium into the helium pipeline until the required pressure is reached.

[0016] Preferably, before S2, S1 is repeated multiple times.

[0017] Preferably, 100 Pa ≤ the first preset value ≤ 200 Pa.

[0018] Preferably, the second preset value is ≥1000 Pa.

[0019] Preferably, 3Pa≤the third preset value≤5Pa.

[0020] In the present invention, the proposed method for evacuating and replacing gas in high-purity helium pipelines for semiconductor equipment uses a dry evacuation pump to evacuate the helium pipeline to be purified to a first preset value, then fill the helium pipeline to be purified with high-purity nitrogen and increase the pressure to a second preset value; evacuate the helium pipeline to be purified to the first preset value again using a dry evacuation pump; further evacuate the helium pipeline to be purified using a cryogenic pump unit, so that the helium pipeline is in a high vacuum state; and introduce high-purity helium into the helium pipeline until the required pressure is reached. The cryogenic pump unit is used, assisted by a dry evacuation pump, to greatly improve the ultimate vacuum degree, and the evacuation flow washing is achieved by repeatedly filling and evacuating the helium pipeline with nitrogen, which greatly saves helium consumption, and has the effects of simple operation and high production efficiency.

[0021] The present invention also provides a semiconductor equipment high-purity helium pipeline gas evacuation replacement system for realizing the above-mentioned semiconductor equipment high-purity helium pipeline gas evacuation replacement method, comprising:

[0022] Dry evacuation pump, used to evacuate the helium pipeline to be purified;

[0023] A cryopump unit for further evacuation of the helium gas line to be purified; and

[0024] The pressure sensor is used to detect the pressure in the helium pipeline to be purified.

[0025] Preferably, it also includes:

[0026] Nitrogen cylinder, used to introduce high-purity helium into the helium pipeline.

[0027] Preferably, it also includes: a four-way connector, a first interface of the four-way connector is connected to the cryogenic pump unit, a second interface of the four-way connector is used to connect the helium pipeline, a third interface of the four-way connector is connected to the dry evacuation pump, and a fourth interface of the four-way connector is connected to the nitrogen cylinder.

[0028] Preferably, a controller is further included, and the four interfaces of the four-way connector are respectively connected to solenoid valves. The controller controls at least one solenoid valve to open / close according to the signal of the pressure sensor.

[0029] Preferably, the cryopump unit comprises a compressor, a GM refrigerator and a cryopump body.

[0030] In the present invention, the high-purity helium pipeline gas evacuation and replacement device for semiconductor equipment proposed adopts a cryogenic pump supplemented by a dry evacuation pump to form a helium pipeline evacuation and purification system. The cryogenic pump has a high ultimate vacuum degree and an ultra-high pumping speed for water, which is much higher than other vacuum pumps. The speed of establishing vacuum is faster, which can greatly increase the output of products. For the helium pipeline purification evacuation, the replacement gas can be selectively extracted, and nitrogen gas flow washing is selected in the evacuation and replacement process. The amount of helium used in the production process is greatly reduced, and the production cost is reduced. After the product is left standing for a long time, the purity of the helium is maintained well. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a schematic structural diagram of an embodiment of a high-purity helium pipeline gas evacuation and replacement system for semiconductor equipment.

[0032] Figure 2 The present invention is a flow chart of an embodiment of a method for evacuating and replacing gas in a semiconductor device pipeline using high-purity helium. DETAILED DESCRIPTION

[0033] like Figure 1 and2 As shown, Figure 1 This is a schematic structural diagram of an embodiment of a high-purity helium pipeline gas evacuation and replacement system for semiconductor equipment proposed by the present invention. Figure 2 The present invention is a flow chart of an embodiment of a method for evacuating and replacing gas in a semiconductor device pipeline using high-purity helium.

[0034] The present invention provides a method for evacuating and replacing high-purity helium pipeline gas for semiconductor equipment, comprising the following steps:

[0035] S1, evacuating the helium pipeline 2 to be purified by a dry evacuation pump 1 until the pressure in the helium pipeline 2 drops to a first preset value and is maintained, and then filling high-purity nitrogen into the helium pipeline 2 to be purified until the pressure in the helium pipeline 2 rises to a second preset value and is maintained;

[0036] In order to improve the cleaning effect, S1 can be repeated multiple times to perform multiple evacuations and nitrogen fillings.

[0037] Specifically, in the specific setting method of the preset pressure value, 100Pa≤first preset value≤200Pa, and the second preset value≥1000Pa.

[0038] S2, evacuating the helium pipeline 2 to be purified again by the dry evacuation pump 1 until the pressure in the helium pipeline 2 drops to a first preset value;

[0039] S3, further evacuating the helium pipeline 2 to be purified by using a cryopump unit until the pressure in the helium pipeline 2 drops to a third preset value and is maintained, so that the helium pipeline 2 is in a high vacuum state;

[0040] Specifically, in the specific setting of the third preset value, 3pa≤third preset value≤5pa.

[0041] S4. Introduce high-purity helium into the helium pipeline 2 until the required pressure is reached.

[0042] In this embodiment, the proposed method for evacuating and replacing the gas in the high-purity helium pipeline for semiconductor equipment is to evacuate the helium pipeline to be purified to a first preset value by a dry evacuation pump, and then fill the helium pipeline to be purified with high-purity nitrogen to increase the pressure to a second preset value; evacuate the helium pipeline to be purified to the first preset value by a dry evacuation pump again; further evacuate the helium pipeline to be purified by a cryogenic pump unit, so that the helium pipeline is in a high vacuum state; and introduce high-purity helium into the helium pipeline until the required pressure is reached. The cryogenic pump unit is used, assisted by a dry evacuation pump, to greatly improve the ultimate vacuum degree, and the evacuation flow washing is achieved by repeatedly filling and evacuating the helium pipeline with nitrogen, which greatly saves helium consumption, and has the effects of simple operation and high production efficiency.

[0043] Reference Figure 1 This embodiment also provides an evacuation replacement system for implementing the above-mentioned method for evacuating and replacing gas in a high-purity helium pipeline for semiconductor equipment, comprising:

[0044] A dry evacuation pump 1, used for evacuating a helium pipeline 2 to be purified;

[0045] a cryogenic pump unit, used for further evacuating the helium gas pipeline 2 to be purified; and

[0046] The pressure sensor is used to detect the pressure in the helium pipeline 2 to be purified.

[0047] In order to facilitate nitrogen filling, the evacuation replacement system of this embodiment further includes: a nitrogen bottle 4 for introducing high-purity helium into the helium pipeline 2.

[0048] In order to facilitate pipeline connection, in a specific implementation, the evacuation replacement system of this embodiment further includes: a four-way connector 6, a first interface of the four-way connector 6 is connected to the cryopump unit, a second interface of the four-way connector 6 is used to connect the helium pipeline 2, a third interface of the four-way connector 6 is connected to the dry evacuation pump 1, and a fourth interface of the four-way connector 6 is connected to the nitrogen bottle 4. During operation, it can be achieved by controlling the on and off of each interface.

[0049] In the specific design, a controller can be provided, and the four interfaces of the four-way connector 6 are respectively connected to solenoid valves, and the controller controls at least one solenoid valve to open / close according to the signal of the pressure sensor 8. The electronic control system is used to control the pipeline evacuation, which can realize the full-automatic evacuation operation after the pipeline is connected, reduce the operation of personnel, and save labor costs.

[0050] In a specific implementation of the cryopump unit, the cryopump unit includes a compressor 9, a GM refrigerator 5 and a cryopump body 3. The compressor and the GM refrigerator cooperate to provide a refrigerant carrying cold air for the cryopump body, thereby realizing the low-temperature gas capture capability of the cryopump unit and ensuring the vacuum effect.

[0051] The compressor in the cryopump unit provides high-pressure helium to the GM refrigerator. The GM refrigerator uses Simon expansion refrigeration to cool the surface inside the pump to an extremely low temperature through a cold head, generally as low as below 20K. At this time, the gas molecules will condense and be adsorbed on the low-temperature surface, thereby achieving the extraction of the gas.

[0052] The following describes in detail the method and system for evacuating and replacing gas in a high-purity helium pipeline for semiconductor equipment of this embodiment through specific examples.

[0053] Reference Figure 1This embodiment provides a high-purity helium transmission pipeline evacuation replacement system for semiconductor equipment, including a cryopump unit, a dry evacuation pump 1, a four-way connector 6, a nitrogen bottle 4, a pressure sensor 8, and a solenoid valve and a control system thereof. The cryopump unit is composed of a compressor 9, a GM refrigerator 5, and a cryopump body 3.

[0054] The cryopump unit is connected to the solenoid valve 71 through a flange adapter, the solenoid valve 71 is connected to the four-way connector 6, and the dry evacuation pump 1 is connected to the four-way connector 6 through a solenoid valve 72. The nitrogen bottle 4 is connected to the four-way connector 5 through a solenoid valve 73. The helium pipeline 2 is connected to the four-way connector 5 through a solenoid valve 74, and the end of the helium pipeline is connected to a pressure sensor 10, and the pressure sensor 10 can be a pressure transmitter. The control system includes a single-chip microcomputer 11 and a solenoid valve controller 10. The single-chip microcomputer 14 collects signals of the solenoid valves 71, 72, 73, and 74, and controls the solenoid valve controller 10 after processing. The solenoid valve controller 10 controls the opening and closing of the solenoid valves 71, 72, 73, and 74.

[0055] During the gas evacuation and replacement process performed by the evacuation and replacement system of this embodiment:

[0056] Reference Figure 2 , keep the solenoid valves 71, 73, and 74 in the system closed, turn on the cryopump unit to cool down, and after the cryopump unit drops to low temperature, connect the helium pipeline 2 to be purified to the system, connect one end of the helium pipeline to the four-way connector 6 using a self-sealing joint, and connect the other end to the pressure sensor 8 using a self-sealing joint. At this time, start the dry evacuation pump 1, open the solenoid valve 72, and use the dry evacuation pump 1 to evacuate the helium pipeline 2 to be purified. The system automatically monitors the value of the pressure sensor 8. When the pressure in the pipeline drops to A (100≤A≤200) pa, the system closes the solenoid valve 72, and a evacuation operation is completed.

[0057] The solenoid valve controller controls the opening of the solenoid valve 73, and high-purity nitrogen is filled into the helium pipeline to be purified. The pressure sensor 8 is automatically monitored. When the pressure in the pipeline rises to C (C ≥ 1000) pa, the solenoid valve 73 is controlled to be closed. At this time, the above-mentioned evacuation operation is repeated twice. After the third evacuation operation is completed, the pressure in the pipeline monitored by the pressure sensor drops to A (100 ≤ A ≤ 200) pa, and the solenoid valve 71 is opened. The cryopump unit is used to further evacuate the helium pipeline to be purified, and the value of the pressure sensor 8 is automatically monitored. When the pressure in the pipeline drops to B (3 ≤ B ≤ 5) pa, the solenoid valve controller controls the closing of the solenoid valve 71. At this time, the helium pipeline is in a high vacuum state, and the connection between the pipeline and the solenoid valve 74 and the pressure sensor 8 is disconnected. The pipeline is offline, connected to high-purity helium (purity> 99.999%), and filled with the required pressure of the product. At this time, the pipeline evacuation and purification operation is completed.

[0058] The present invention takes a cryogenic pump system as the core, and uses a dry pump to evacuate and purify the helium pipeline. It introduces a cryogenic pump system for the first time in the purification and production process of high-purity helium and provides an automated production control method for helium pipeline purification. The standard cryogenic vacuum pump can achieve a maximum vacuum degree of 10-7Pa, and can also achieve 10-9Pa without other auxiliary pumps. Theoretically, it can even reach an extremely high vacuum of more than 10-11Pa. It has an ultra-high pumping speed for water, which is much higher than other vacuum pumps. The vacuum is established faster, which can greatly increase the product output. At the same time, high-purity nitrogen is used in the flow and flushing process of the pipeline, which greatly saves helium consumption. It has the characteristics of simple operation, high production efficiency, and good economic benefits. The production process adopts fully automatic evacuation and flow flushing operations. After connecting the helium tube, the production operation can be fully automatic, which improves production efficiency.

[0059] The present invention adopts a cryopump unit, assisted by a dry pump and an electronic control system to perform a fully automatic purification production operation on a helium pipeline, including a process of vacuum purification operation and a control judgment logic of the electronic control system.

[0060] The present invention adopts an electric control system to control the pipeline evacuation, which can realize the full-automatic evacuation operation after the pipeline is connected, reduce the number of personnel operations, and the operation process can be unattended, saving labor costs;

[0061] The present invention adopts a cryopump unit, assisted by a dry pump, to evacuate the helium pipeline. The working process is clean and pollution-free. A low-temperature cold plate is used to condense and adsorb gas to obtain and maintain vacuum. There are no moving parts and oil in the vacuum area, which is clean and pollution-free.

[0062] The present invention adopts high-purity nitrogen to replace high-purity helium for pipeline flow washing operation, which has low production cost and good economic benefit.

[0063] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for evacuating and replacing high-purity helium pipeline gas for semiconductor equipment, characterized in that: The following steps are involved: S1. evacuating the helium pipeline (2) to be purified by using a dry evacuation pump (1) until the pressure in the helium pipeline (2) drops to a first preset value and is maintained therein, and then filling the helium pipeline (2) to be purified with high-purity nitrogen until the pressure in the helium pipeline (2) rises to a second preset value and is maintained therein; S2, evacuating the helium pipeline (2) to be purified again by using the dry evacuation pump (1) until the pressure in the helium pipeline (2) drops to a first preset value; S3, further evacuating the helium pipeline (2) to be purified by using a cryopump unit until the pressure in the helium pipeline (2) drops to a third preset value and is maintained there, so that the helium pipeline (2) is in a high vacuum state; S4. Introduce high-purity helium into the helium pipeline (2) until the required pressure is reached.

2. The method for evacuating and replacing high-purity helium pipeline gas for semiconductor equipment according to claim 1, characterized in that: Before S2, repeat S1 multiple times.

3. The method for evacuating and replacing high-purity helium pipeline gas for semiconductor equipment according to claim 1, characterized in that: 100pa≤first preset value≤200pa.

4. The method for evacuating and replacing gas in a semiconductor device pipeline using high-purity helium according to claim 1, wherein: The second preset value is ≥1000pa.

5. The method for evacuating and replacing gas in a semiconductor device pipeline using high-purity helium according to claim 1, wherein: 3pa≤the third preset value≤5pa.

6. A semiconductor equipment high-purity helium pipeline gas evacuation and replacement system for realizing the semiconductor equipment high-purity helium pipeline gas evacuation and replacement method according to any one of claims 1 to 5, characterized in that: include: A dry evacuation pump (1) for evacuating a helium pipeline (2) to be purified; A cryogenic pump unit, used for further evacuating the helium gas pipeline (2) to be purified; and The pressure sensor (8) is used to detect the pressure in the helium pipeline (2) to be purified.

7. The evacuation replacement system according to claim 6, characterized in that: Also includes: The nitrogen cylinder (4) is used to introduce high-purity helium into the helium pipeline (2).

8. The high-purity helium pipeline gas evacuation and replacement system for semiconductor equipment according to claim 7, characterized in that: Also includes: A four-way connector (6), wherein a first interface of the four-way connector (6) is connected to a cryogenic pump unit, a second interface of the four-way connector (6) is used to connect a helium pipeline (2), a third interface of the four-way connector (6) is connected to a dry evacuation pump (1), and a fourth interface of the four-way connector (6) is connected to a nitrogen bottle (4).

9. The high-purity helium pipeline gas evacuation and replacement system for semiconductor equipment according to claim 8, characterized in that: It also includes a controller, wherein the four interfaces of the four-way connector (6) are respectively connected to electromagnetic valves, and the controller controls at least one electromagnetic valve to open / close according to a signal from the pressure sensor (8).

10. The high-purity helium pipeline gas evacuation and replacement system for semiconductor equipment according to claim 6, characterized in that: The cryopump unit comprises a compressor (9), a GM refrigerator (5) and a cryopump body (3).

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