Gas processing equipment and vacuum lines

Abstract

A gas processing apparatus (6) configured to process gas pumped by at least one coarse pumping device (10) at atmospheric pressure, the gas processing apparatus (6) including a processing chamber (26) and at least one discharge pipe (7) configured to connect the discharge port (8) of the at least one coarse pumping device (10) to the inlet (9) of the processing chamber (26), characterized in that the gas processing apparatus (6) further includes at least one auxiliary pumping device (13) configured to reduce the pressure in the at least one discharge pipe (7), the auxiliary pumping device being located less than 1 meter, for example less than 50 centimeters, from the inlet (9) of the processing chamber (26).

Description

Technical Field

[0001] The present invention relates to a gas processing apparatus and a vacuum pipeline comprising the gas processing apparatus. Background Technology

[0002] In the semiconductor, flat panel display, and photovoltaic manufacturing industries, manufacturing methods use gases that are typically processed by a gas handling unit after passing through a rough vacuum pump.

[0003] Some of these methods are considered risky because the gases passed through the vacuum line are flammable and / or explosive. Examples include hydrogen, silanes, tetraethyl orthosilicate (TEOS), and hydrides.

[0004] In addition to these hazardous gaseous substances, vacuum lines can also contain reducing solids, i.e., non-oxidizing deposits, such as silica dust or polysilane polymers. These deposits can accumulate over time and contribute to additional hazardous emergency conditions. Some non-oxidizing deposits are highly flammable. They can ignite, for example, especially due to a sudden pumping of a strong gas flow or simply because an operator vents the tubing or vacuum pump during maintenance.

[0005] Some explosions can be particularly destructive because they release enormous amounts of energy. This is especially true of chain explosions. The initial explosion is triggered by a flammable gas. This explosion agitates deposits of reduced solids that may be present in the pipe. These flammable solid deposits, agitated by the shockwave from the explosion, then explode in a "super-explosion."

[0006] The risk of personal injury and equipment damage is therefore extremely high.

[0007] The current approach to this problem is to continuously dilute the pumping gas with a neutral gas—typically nitrogen. The neutral gas flow rate is determined to accommodate the most undesirable pumping conditions, along with a safety margin.

[0008] However, this solution has many drawbacks.

[0009] First, the large-scale supply of nitrogen in the vacuum line involves additional costs related to gas consumption and the energy consumption of the vacuum pump, heating equipment, and gas handling equipment used to process the significantly diluted gas flow. Furthermore, the cooling of the vacuum line caused by gas dilution leads to other disadvantages, particularly due to the cost and risk of failure of the heating elements. The large-scale supply of this neutral gas also necessitates a higher cost for the gas handling and roughing pumping equipment.

[0010] Furthermore, diluted nitrogen leads to the formation of nitrogen oxides or "NOx" in gas processing units. xFor example, NO2. Nitrogen oxides are toxic and constitute air pollutants that must be treated.

[0011] Finally, this solution has been observed to reach its limits because, for some recent processes, the increase in diluent gas is becoming insufficient, either due to inadequate pumping capacity of the vacuum pump or insufficient processing capacity of the gas handling unit. These extreme operating conditions can raise issues concerning the reliability of the vacuum pump or the gas handling unit.

[0012] Another solution might be to reduce the temperature of the tubes and vacuum pump, especially to avoid thermal decomposition of the precursors and minimize chemical reactions. However, it is equally important to maintain a high temperature to avoid the risk of deposition due to condensation.

[0013] Another issue is that certain processes—particularly in the semiconductor industry—tend to increase the use of unstable precursors. Substrate patterns are becoming increasingly thinner and the substrates increasingly thicker, meaning they have numerous layers fabricated over many process steps. To reduce the thermal balance that could damage the chip substrate, nascent molecules that decompose at lower temperatures are used. The downside is that they are also more prone to deposition in vacuum pipelines, which can lead to significant deposition.

[0014] In addition, some of the condensable gaseous substances used can solidify into solid byproducts, particularly deposited in layers on the dynamic or static parts of vacuum pumps or pipes, which can lead to pipeline blockage. Summary of the Invention

[0015] One object of the present invention is to increase the safety of pumping devices and vacuum lines for conveying flammable and / or explosive gases. Another object is to reduce the deposition of condensable substances in discharge pipes and pumping devices, or to delay or minimize the decomposition of precursors that decompose at lower temperatures.

[0016] Therefore, the present invention relates to a gas processing apparatus configured to process gas pumped by at least one coarse pumping device at atmospheric pressure. The gas processing apparatus includes a processing chamber and at least one discharge pipe configured to connect the discharge port of at least one coarse pumping device to the inlet of the processing chamber. The gas processing apparatus is characterized in that it further includes at least one auxiliary pumping device configured to reduce the pressure in the at least one discharge pipe and located less than 1 meter, for example less than 50 centimeters, from the inlet of the processing chamber.

[0017] Reducing the pressure in the discharge line makes it possible to ensure the safety of the vacuum line and simultaneously prevent the deposition of condensable substances in the discharge line and pumping unit, which may reduce the heating requirements of the line. Reducing the heating of the line may prevent thermal decomposition, thereby reducing the kinetics of precursor transformation and chemical activity in the pumping unit, potentially reducing undesirable reactions. Reducing heating may also help maintain the quality of the lubricant and improve the reliability of the pumping unit's mechanical components, particularly bearings. This can thus increase the interval between maintenance operations.

[0018] Furthermore, reducing the pressure in the discharge pipe may limit the consumption of dilution gas, which may also reduce the energy consumption of pumping and gas treatment devices, and minimize or even eliminate the formation of nitrogen oxides in the gas treatment device.

[0019] Reducing the pressure in the vacuum line also reduces the pressure in the coarse pumping unit, which makes it possible to reduce its size and use less robust and therefore cheaper materials.

[0020] The gas processing device may further include the features described below, which may be applied individually or in combination.

[0021] An auxiliary pumping device can be installed in the treatment chamber.

[0022] Auxiliary pumping devices may include a Venturi gas injection pump, which is installed in the head of the burner in the treatment chamber.

[0023] The gas treatment apparatus may include at least one bypass device inserted between the discharge pipe and the auxiliary pumping device, the bypass device comprising:

[0024] -Inlet port, which connects to the discharge pipe.

[0025] - The first outlet port is connected to an auxiliary pumping unit connected to the processing chamber.

[0026] - The second exit port is configured to bypass (avoid, forming a bypass path) the processing chamber.

[0027] - A control component configured to connect the inlet port to either the first outlet port or the second outlet port.

[0028] The bypass device can be a controllable three-way valve.

[0029] If the gas processing apparatus includes at least two bypass devices, and their first outlet ports are connected to the processing chamber via auxiliary pumping devices, then the gas processing apparatus may include:

[0030] - At least two isolation valves are arranged at the corresponding discharge ports of the coarse pumping unit.

[0031] - A processing unit, which is connected to the isolation valve and to a pressure sensor located at the corresponding discharge port of the coarse pumping device downstream of the isolation valve, is configured to control all isolation valves except one isolation valve to close for a predetermined period of time, thereby generating an alarm when the pressure sensor reading from the discharge pipe of its open isolation valve exceeds a predetermined threshold.

[0032] The gas processing apparatus may include at least one additional auxiliary pumping device connected to at least one second outlet port of the bypass device and configured to reduce the pressure in the second outlet port.

[0033] The gas processing device may include:

[0034] - A pressure sensor configured to measure the pressure in the second outlet port, and

[0035] - A processing unit connected to a pressure sensor and configured to generate an alarm when the pressure measurement exceeds a predetermined threshold.

[0036] The gas processing apparatus may include at least one neutral gas injection device configured to inject neutral gas into an auxiliary pumping device and / or inject it at the outlet of the auxiliary pumping device.

[0037] Gas processing apparatus may include a processing unit configured to control the pumping speed of an additional auxiliary pumping device, so as to

[0038] - When no control component connects the inlet port to the second outlet port, the pumping speed is controlled to the first speed, and

[0039] - When at least one control element connects the inlet port to the second outlet port, the pumping speed is controlled to a second speed, which is higher than the first speed.

[0040] Gas processing apparatus may include a processing unit configured to control the pumping rate of an additional auxiliary pumping device, so as to:

[0041] - When at least one measurement from the pressure sensor at the discharge port of the coarse pumping unit is below or equal to a threshold, the pumping speed is controlled to a first speed, and

[0042] - When the measured value exceeds the threshold, the pumping speed is controlled to a second speed, which is higher than the first speed.

[0043] Gas processing apparatus may include a processing unit configured to control the pumping rate of an additional auxiliary pumping device, so as to:

[0044] - When the concentration of combustible gas or gas capable of causing deposition is below or equal to a predetermined threshold, the pumping speed is controlled to a first speed, and

[0045] When the concentration of combustible gas or gas that can cause deposition exceeds the threshold, the pumping speed is controlled to a second speed, which is higher than the first speed.

[0046] Auxiliary pumping devices and / or additional auxiliary pumping devices may include water jet pumps and / or Venturi gas jet pumps and / or liquid ring pumps and / or dry vacuum pumps and / or impeller pumps (vane pumps).

[0047] The treatment chamber may include a burner and / or an electrical system and / or a plasma (electromagnetic) system and / or a scrubber and / or a chemical adsorption cartridge and / or a physical adsorption cartridge.

[0048] Auxiliary pumping devices may include Venturi gas injection pumps, whose driving gases include fuel and / or combustion oxidizers and / or neutral gases.

[0049] A Venturi gas jet pump may include a heating element configured to heat the driving gas.

[0050] Gas handling apparatus may include a bypass pipe configured to bypass auxiliary pumping devices and / or additional auxiliary pumping devices in the event of overpressure.

[0051] The present invention also relates to a vacuum line comprising the gas processing apparatus described above. Attached Figure Description

[0052] Further features and advantages of the invention will become apparent from the description of the non-limiting examples and with reference to the accompanying drawings, in which:

[0053] Figure 1 The diagram shows an example of a facility, showing only those elements necessary for understanding the invention.

[0054] Figure 2A A schematic diagram showing a variant of a vacuum pipeline.

[0055] Figure 2B A schematic diagram showing another variation of the vacuum pipeline.

[0056] Figure 2C A schematic diagram showing another variation of the vacuum pipeline.

[0057] Figure 2D A schematic diagram showing another variation of the vacuum pipeline.

[0058] Figure 2E A schematic diagram showing another example of a vacuum pipeline.

[0059] Figure 3 The graph shows the explosion pressure (symbols represent measured values, solid lines represent theoretical values) in millibars (mbars) before the explosion, depending on the hydrogen concentration (the proportion of molecules in the air): 100 mbar (10,000 Pa) (hollow triangle), 150 mbar (15,000 Pa) (solid cube), 200 mbar (20,000 Pa) (hollow rhombus), 300 mbar (30,000 Pa) (circle), 500 mbar (50,000 Pa) (solid triangle), 750 mbar (75,000 Pa) (solid cube), 1,000 mbar (100,000 Pa) (solid rhombus).

[0060] Figure 4 A schematic diagram showing another example of a vacuum pipeline.

[0061] Figure 5 A schematic diagram showing another example of a vacuum pipeline.

[0062] In these figures, equivalent elements use the same reference numerals. Detailed Implementation

[0063] The following embodiments are examples. Although the description refers to one or more specific embodiments, this does not necessarily mean that each reference relates to the same specific embodiment or feature applies only to a single specific embodiment. Individual features of multiple embodiments can also be combined or interchanged to provide other specific embodiments.

[0064] A rough vacuum pump is a positive displacement vacuum pump, constructed to draw in, transfer, and then discharge the gas to be pumped at atmospheric pressure. The rotor of a rough vacuum pump can be Roots, claw, helical, impeller, or scroll type. Rough vacuum pumps are also designed to start at atmospheric pressure.

[0065] A positive displacement vacuum pump, constructed using two Roots rotors to draw in, transfer, and then discharge the gas to be pumped, is defined as a Roots vacuum pump or Roots blower. The Roots vacuum pump is installed upstream of and in series with a rough vacuum pump. The rotors are held by two shafts, which are rotated by the Roots vacuum pump's motor.

[0066] The main difference between a Roots vacuum pump and a rough vacuum pump is that the former has a larger pumping stage size and a larger tolerance due to its higher pumping capacity. Furthermore, a Roots vacuum pump cannot discharge at atmospheric pressure and must be installed in series upstream of a rough vacuum pump for use.

[0067] An "upstream" element refers to an element positioned in front of another element relative to the direction of gas flow in the pump. Conversely, a "downstream" element refers to an element positioned behind another element relative to the direction of gas flow in the pump.

[0068] Facility 1 includes equipment 2, which includes one or more processing chambers 3 connected to one or more vacuum lines 4. The processing chambers 3 are adapted to receive one or more substrates, such as semiconductor wafers, flat panel displays, or photovoltaic panels.

[0069] The vacuum line 4 includes: one or more pumping devices 5 connected to at least one processing chamber 3; and one or more gas processing devices 6 including one or more exhaust pipes 7 connecting the exhaust port 8 of at least one coarse pumping device 10 to the inlet 9 of the processing chamber 26 of the gas processing device 6. Figure 1 For example, semiconductor device 2 is shown, with its processing chamber 3 connected to vacuum line 4. The discharge pipe 7 can have varying lengths. Between the output of the coarse pumping device 10 and the input 9 of the processing chamber 26, they can have lengths between one and four meters.

[0070] The pumping device 5 includes at least one roughing pump 10 configured to discharge pumped gas at atmospheric pressure at the discharge port 8 or at a pressure greater than atmospheric pressure—particularly within 1,200 millibars (120,000 Pascals). The roughing pump 10 can also discharge pumped gas at a pressure below atmospheric pressure.

[0071] The pumping device 5 may further include at least one high-vacuum pumping device, which is arranged upstream of and in series with the coarse pumping device 10 in the direction of gas flow and is inserted between the processing chamber 3 and the coarse pumping device 10. The high-vacuum pumping device may include a Roots compressor 11 and / or a turbomolecular vacuum pump 12.

[0072] The processing chamber 26 is configured to process the gas pumped by the coarse pumping device 10 at atmospheric pressure.

[0073] In a manner known per se, the processing chamber 26 includes, for example: a burner 23 configured to generate a thermal reaction at high temperature by combustion of hydrocarbons; and / or an electrical system configured to generate a thermal reaction at high temperature by heating a resistor; and / or a plasma; and / or a scrubber; and / or a chemical adsorption cartridge and / or a physical adsorption cartridge.

[0074] according to Figure 1In the exemplary embodiment shown, the processing chamber 26 includes a burner 23 and a scrubber 24 arranged in series with and downstream of the burner 23 in the gas flow direction. The burner 23 can be a combustion, electric, or plasma burner. A reactive gas, such as oxygen or air, is added to the pumped gas, which is brought to extremely high temperatures by the burner 23. This activates the formation of new chemically reactive soluble substances, which can then be captured by the scrubber 24. A water mist can be generated in the burner 23 through a water injection nozzle (typically also known as a quenching nozzle), thereby rapidly cooling the gas and preventing chemical equilibrium from being achieved, rather than allowing the dissociated hot gases to recombine or react towards an adverse equilibrium. The scrubber 24 includes, for example, a packed column (packed tower) in which the pumped gas rises against the water flow. At the outlet 31 of the gas processing unit 6, the gas can be discharged into the atmosphere or into a central scrubber in a manufacturing plant.

[0075] The gas processing device 6 further includes at least one auxiliary pumping device 13 configured to reduce the pressure in at least one discharge pipe 7. Figure 1 , 4 and 5).

[0076] The auxiliary pumping device 13 can be of any type. It includes, for example, […]. Figure 1 The water jet pump (or water jet impingement) and / or Venturi gas jet pump and / or liquid ring pump and / or dry vacuum pump shown are examples of Roots, claw and / or screw vacuum pumps and / or impeller and / or scroll and / or diaphragm or membrane pumps.

[0077] If the auxiliary pumping device 13 includes a Venturi gas injection pump, the driving gas injected to reduce the pressure may include a neutral gas, such as nitrogen. The driving gas thus helps to further dilute the pumped gas from the exhaust pipe 7. The driving gas may also include fuel—such as methane and / or an oxidizer. The driving gas thus similarly helps to further dilute the pumped gas from the exhaust pipe 7 without reducing the efficiency of the burner 23 of the gas treatment device 6 and without producing nitrogen oxides.

[0078] The Venturi gas ejector pump may include a heating element configured to heat the drive gas. The drive gas may be heated to a temperature greater than 50°C, for example, greater than 500°C. Heating the drive gas may improve the efficiency of the burner 23 of the gas processing unit 6 and may prevent powder deposition at the ejector pump outlet. The drive gas may be heated, for example, by a heat exchanger in contact with the hot parts of the processing chamber 26 or the pumping unit 5, which may reduce power consumption.

[0079] The gas jet pump has the advantage of not consuming electricity. It is compact and lightweight, thus easily integrated into the pumping unit 5 or the gas handling unit 6. Figure 2A ).

[0080] If the auxiliary pumping device 13 includes a dry vacuum pump, the purge gas of the auxiliary vacuum pump 13 may include a neutral gas, such as nitrogen, and / or fuel, such as methane, and / or a combustion-supporting agent. The purge gas may be further heated to a temperature, for example, greater than 50°C, or for example, greater than 500°C, through a heat exchanger that is in contact with the hot part of the processing chamber 26 or the pumping device 5.

[0081] The at least one auxiliary pumping device 13 is located at the inlet 9 of the processing chamber 26, that is, at a distance of less than 1 meter, for example less than 50 centimeters. This generally requires raising the auxiliary pumping device 13, since the burner inlet 9 is generally positioned more than 1.50 meters above the ground.

[0082] Generally, the pumping capacity of the auxiliary pumping device 13 is preferably smaller than that of the coarse pumping device 10, for example, greater than 5 m³ / s. 3 / h and / or, for example, less than 100m 3 / h. Under these conditions, the auxiliary pumping unit 13—particularly comprising a dry vacuum pump, liquid ring pump, or impeller pump—can be lightweight enough to be positioned as close as possible to the inlet 9 of the processing chamber 26. Figure 2A For example, in processing chamber 26 ( Figure 2B (and there is no risk and no special handling required.)

[0083] A Venturi gas injection pump type auxiliary pumping device 13 is installed, for example, in the head of the burner 23 of the gas processing device 6. Figure 2B In this situation, a single auxiliary pumping unit 13 installed in the treatment chamber 26 may reduce the pressure in several discharge pipes 7. Figure 5 Fuel and the combustion-supporting agent for the driving gas are the gas supply sources for the burner flame.

[0084] Vacuum line 4 may further include at least one bypass pipe 14 configured to bypass auxiliary pumping device 13 and / or additional auxiliary pumping device 27, as will be seen below, in the event of overpressure. Figure 2C , 4 and 5).

[0085] The bypass pipe 14 includes a tube that bypasses the auxiliary pumping device 13 or the additional auxiliary pumping device 27, and a controllable valve or check valve arranged in the tube and configured to open or close according to the pressure difference across the check valve / valve. The bypass pipe 14 makes it possible to bypass the auxiliary pumping device 13 or the additional auxiliary pumping device 27 to avoid pumping capacity limitations it may cause, especially when pumping strong gas flows or in the event of failure of the auxiliary pumping device 13 or the additional auxiliary pumping device 27.

[0086] Bypass pipe 14 can also bypass gas processing device 6 ( Figure 2DHowever, only during the period of venting air volume at atmospheric pressure, without dangerous gaseous substances. In this case, bypass valve 14 is equipped with a controllable valve that is normally open, i.e., it is open when there is no signal or in case of failure, and can be controlled to close only by dry contact from the treatment chamber 3 when no treated gas is introduced into the treatment chamber.

[0087] When the auxiliary vacuum pump 13 and / or the additional auxiliary pumping device 27 includes a Venturi gas jet pump, this can be incorporated into the check valve of the bypass line 14. Figure 2E The movable stop of the check valve thus has a venturi passage. The check valve can be in a closed position, in which, when drive gas is injected into the inlet of the venturi passage, the check valve forms an ejector pump for the auxiliary vacuum pump 13 or the additional auxiliary pumping device 27. The check valve can also be in an open position, in which, when the pressure difference across the check valve is greater than the check valve's load threshold, the pumped gas bypasses the venturi passage.

[0088] return Figure 1 As can be seen, the vacuum line 4 may include a dilution gas injection device 15, a pressure sensor 16 configured to measure the pressure in the discharge pipe 7, and a control unit 17 connected to the pressure sensor 16.

[0089] The dilution gas injection device 15 is configured to inject a dilution gas, such as a neutral gas like nitrogen, into the discharge pipe 7 and / or the roughing pump 10 and / or the auxiliary pump 13. The dilution gas may be injected, for example, into the inlet and / or outlet 8 of the roughing pump 10 and / or into the last two pumping stages of the multi-stage roughing vacuum pump of the roughing pump 10.

[0090] Pressure sensor 16 is arranged, for example, at the discharge port 8 of coarse pumping device 10.

[0091] The control unit 17 includes a controller, a microcontroller, a memory, and a computer program that enables it to implement methods for controlling the vacuum line. It is, for example, a computer or a programmable logic controller.

[0092] The control unit 17 can be configured to control the auxiliary pumping device 13 and the dilution gas injection device 15 based on changes in pressure measured by the pressure sensor 16, depending on a first operating mode or a second operating mode.

[0093] In the first operating mode, the pressure in the discharge pipe 7 is maintained at less than or equal to 200 mbar (20,000 Pa).

[0094] The auxiliary pumping device 13, which makes it possible to reduce the pressure in the discharge pipe 7, can be controlled to pump continuously or intermittently.

[0095] For example, the auxiliary pumping device 13 includes a Venturi gas jet pump, and the control unit 17 is configured to control the driving gas of the jet pump to reduce the pressure.

[0096] According to another example, the auxiliary pumping device 13 includes a water jet pump, and the control unit 17 is configured to control the driving fluid of the water jet pump to make it possible to reduce the pressure ( Figure 1 ).

[0097] In this configuration, according to one embodiment, the auxiliary pumping device 13 further includes a hydraulic pump 19, the outlet of which is configured to be controlled by the control unit 17 to supply driving fluid to the water jet pump. The inlet of the hydraulic pump 19 is, for example, placed in communication with the bath liquid 22 of the scrubber 24 of the gas processing device 6. The gas processing device 6 may include a gas / water separator 20 inserted between the water jet pump of the auxiliary pumping device 13 and the inlet 9 of the burner 23 of the gas processing device 6. Residual liquid may be discharged into the bath liquid 22 via the plunger tube 21.

[0098] In the first operating mode—which is the default optimal operating mode—the pressure is therefore maintained below the ignition conditions of most combustible gases transmitted in the exhaust pipe 7.

[0099] This can be used as a reference. Figure 3 For better understanding, the diagram illustrates hydrogen pressures of 100 mbar (10,000 Pa), 150 mbar (15,000 Pa), and 200 mbar (20,000 Pa), with the explosion pressure remaining below 1,600 mbar (160,000 Pa) under stoichiometric conditions (which would lead to the most severe explosion). Therefore, a set of safety conditions is established in the coarse pumping unit 10 and the discharge pipe 7 to prevent gas explosions. For pressures less than or equal to 200 mbar (20,000 Pa), it is considered that the pressure generated by ignition under stoichiometric conditions (also known as the explosion pressure) can be easily contained, meaning it does not cause significant mechanical damage to the pumping unit 5 or the piping. Although Figure 3 The exception applies to hydrogen, but the same behavior is observed for all flammable gases: the explosion pressure remains below 1,600 mbar (160,000 Pa) under the stoichiometric conditions (which would lead to the most severe explosions).

[0100] Furthermore, in the first operating mode, it is not necessary to inject dilution gas outside of flammable and / or explosive conditions, as safety is ensured by a vacuum level of less than 200 mbar (20,000 Pa). The control unit 17 can therefore control the cessation of dilution gas injection into the discharge pipe 7 or the pumping device 5.

[0101] The control unit 17 can also be configured to shut off the injection of purge gas into the coarse pump 10 in the first operating mode. This makes it easier to maintain a low pressure in the discharge line 7.

[0102] If it is not possible to reduce the pressure to less than 200 mbar (20,000 Pa), the control unit 17 is configured to switch to a second operating mode.

[0103] In the second operating mode, the pressure in the discharge pipe 7 is greater than 20,000 Pa. The control unit 17 is further configured to control the injection of dilution gas into the discharge pipe 7 or the pumping device 5 via the dilution gas injection device 15. In this second operating mode—which can be considered a “degraded” operating mode—the risk of flammability can be controlled through dilution.

[0104] The control unit 17 may be configured such that the flow rate of the diluent gas introduced into the discharge pipe 7 or the pumping device 5 in the second operating mode is determined based on the pressure measured by the pressure sensor 16, so that, particularly under chemical mixing conditions, i.e., under the worst combustible gas concentration conditions, the pressure (or explosion pressure) generated by ignition is kept less than 160,000 Pa (1,600 mbar).

[0105] For example, refer to Figure 3 As can be seen, when the initial pressure measured by pressure sensor 16 before the explosion is 300 mbar (30,000 Pa) (circle), the 32% H2 concentration under the stoichiometric conditions must be reduced to the target H2 concentration of 15%, i.e., diluted with a neutral gas, so that the pressure does not exceed the explosion pressure of 1,600 mbar (160,000 Pa). According to another example in the figure, when the pressure measured by pressure sensor 16 is 500 mbar (50,000 Pa) (triangle), the concentration under the stoichiometric conditions must be reduced to 6-7% through dilution to maintain an explosion pressure below 1,600 mbar (160,000 Pa).

[0106] The concentration of combustible gas before dilution is determined in advance by the user based on the value of the maximum flow (flow rate, velocity) of the combustible gas introduced into the treatment chamber 3.

[0107] When there are several combustible gases, the neutral gas dilution rate is determined based on the maximum flow rate of the combustible gas simultaneously injected into the treatment chamber 3.

[0108] More specifically, firstly, for each type of combustible gas, a method using... Figure 3 The data table for each gas is shown to determine the dilution rate based on the pressure measured by pressure sensor 16. This data table can be stored in control unit 17. Then, the target—dilution—concentration for each gas is recalculated for all combustible gases introduced simultaneously into processing chamber 3; simultaneous injection of all gases mutually contributes to reducing their individual concentrations.

[0109] The dilution rate is therefore determined based on the amount (flow rate, pressure) of the flammable / explosive gas, so that the pressure (or explosion pressure) generated by ignition is kept below 160,000 Pa (1,600 mbar).

[0110] In addition, the diluent gas may include fuel and / or neutral gas. The control unit 17 may be configured to determine the amount and ratio of neutral gas and fuel in the diluent gas based on information related to the combustible gas in the intake processing chamber 3, such as the formulation.

[0111] For example, in the case where the formulation alternates between a TEOS precursor gas deposition step and an NF3 gas cleaning step, the control unit 17, which has already accessed this information, can increase the amount of fuel injected during the deposition step, which makes it possible to facilitate the conversion of TEOS residues into soluble substances.

[0112] This information can also be used to control the flame temperature of burner 23.

[0113] The control unit 17 may be further configured to control the injection of a high flow rate of diluent gas into the discharge line 7 and / or the pumping device 5 when the measured pressure exceeds 50,000 Pa (500 mbar). This high flow rate of diluent gas may be preferentially injected into the pumping device 5 and optionally simultaneously injected into the discharge line 7.

[0114] The hyperdiluent gas flow rate is determined, for example, based on the maximum flow rate of combustible gas that can be injected into processing chamber 3. This information is determined in advance by the user based on the value of the maximum flow rate of combustible gas introduced into the processing chamber. The hyperdiluent gas flow rate is, for example, predetermined to ensure that the combustible gas concentration is less than 25% of the lower explosive limit (LEL).

[0115] The most undesirable pumping conditions are thus made safe, such as the worst-case variations in the formulation implemented in processing chamber 3, plus a safety margin provided by LEL of 25%. This is an emergency operating mode, used occasionally in extreme environments, which is similar to normal operation of existing technologies that would lead to excessive nitrogen consumption. Maximum dilution is therefore sporadic, which allows for savings in dilution gas consumption and energy budget.

[0116] refer to Figure 3 When the hydrogen pressure is greater than 500 mbar (50,000 Pa), the concentration of hydrogen H2 in the discharge pipe 7 can be reduced to less than 1%, which is 25% of the lower explosive limit (LEL), as recommended by the prior art.

[0117] In the first operating mode, the control unit 17 therefore maintains the pressure in the discharge pipe 7 at less than 200 mbar (20,000 Pa).

[0118] If the pressure measured in the discharge pipe 7 remains below 200 mbar (20,000 Pa), the control unit remains in the first operating mode.

[0119] If it is not possible to maintain less than 200 mbar (20,000 Pa) using the auxiliary pumping device 13, especially due to the insufficient capacity of the auxiliary pumping device 13, the control unit switches to the second operating mode.

[0120] In the second operating mode, the control unit 17 controls the injection of dilution gas into the discharge pipe 7 or into the pumping device 5.

[0121] When the pressure is between 200 mbar (20,000 Pa) and 500 mbar (50,000 Pa), the flow rate of the dilution gas introduced into the discharge pipe 7 or the pumping device 5 can be determined based on the pressure measured by the pressure sensor 16 or based on information related to the combustible gas introduced into the treatment chamber 3, so that under the most severe explosion conditions, such as chemical mixing conditions, the explosion pressure remains less than 1,600 mbar (160,000 Pa).

[0122] When the pressure measured in the discharge pipe 7 is greater than 200 mbar (20,000 Pa) and less than 500 mbar (50,000 Pa), the pressure in the discharge pipe 7 is therefore first controlled by the capacity of the auxiliary pumping device 13, and then by the dilution gas setpoint required for dilution pumping gas, which is controlled according to the pressure measured in the discharge pipe 7 and according to information related to the combustible gas introduced into the treatment chamber 3.

[0123] In the second operating mode, if the measured pressure returns to less than 200 mbar (20,000 Pa), the control unit switches back to the first operating mode.

[0124] If the pressure exceeds 500 mbar (50,000 Pa), the diluent gas can be injected directly into the coarse pumping unit 10 at a predetermined high flow rate, thus making even the most undesirable pumping conditions safe, with a safety margin.

[0125] As explained above, reducing the pressure in the discharge line 7 can limit the injection of diluent gas to the most critical conditions. Besides ensuring the safety of vacuum line 4, reducing the pressure can also prevent condensable substances from depositing in the discharge line 7, potentially reducing the heating requirements of the line. Furthermore, reducing the heating of the line can also prevent thermal decomposition, thereby reducing the conversion of heat-sensitive precursors in the pumping unit 5. This combination of low pressure and low temperature also makes it possible to reduce the kinetics of chemical activity, potentially reducing undesirable chemical reactions, whether corrosive or capable of clogging components of vacuum line 4. Reducing heating also makes it possible to maintain the quality of the lubricant and improve the reliability of the mechanical parts of the pumping unit 5, particularly the bearings. This can significantly increase the interval between maintenance operations, improving the economics of vacuum line 4 and the uptime of manufacturing equipment. From an economic point of view, the use of expensive materials can also be reduced. The components of the pumping unit 5 can be standardized in both design and materials, simplifying supply and making it universal.

[0126] Furthermore, the consumption of dilution gas is limited, which also reduces the energy consumption of the pumping device 5 and the gas processing device 6, and minimizes or even eliminates the nitrogen oxides formed in the gas processing device 6.

[0127] according to Figure 1 In the exemplary embodiment shown, the gas processing device 6 may also include at least one bypass device 25 inserted between the discharge pipe 7 and the auxiliary pumping device 13.

[0128] The bypass device 25 includes: an inlet port 25a connected to the discharge pipe 7; a first outlet port 25b connected to an auxiliary pumping device 13 connected to the treatment chamber 26; a second outlet port 25c configured to bypass the treatment chamber 26; and a control member configured to position the inlet port 25a in communication with either the first outlet port 25b or the second outlet port 25c. The bypass device 25 is, for example, a controllable three-way valve.

[0129] When the pumped gas does not require treatment, the bypass device 25 may bypass the auxiliary pumping device 13 and the treatment chamber 26 via the second outlet port 25c. The pumped gas can thus be directed toward the central scrubber of the manufacturing plant.

[0130] The control unit can be manually operated. Maintenance personnel can operate the control unit during maintenance, such as during maintenance work in the treatment chamber 26, to remove gas from the treatment chamber 26. Therefore, when, for example, the burner 23 malfunctions or requires maintenance, the pumped gas can be redirected by the bypass device 25.

[0131] The control unit can select the first or second outlet port 25b, 25c, for example, based on information from the processing chamber 3, such as the status of the processing chamber 3 (processing, off, or standby), or information indicating whether the gas must be processed. For example, gas from a closed or standby processing chamber 3 can therefore bypass the burner 23 without processing and via the bypass device 25. Information such as dry contact or pneumatic control can directly control the switching of the control unit. For example, each processing chamber 3 has one bypass device 25, and each device 2 has several processing chambers 3.

[0132] Several processing chambers 3 and therefore several bypass devices 25 can be further connected to a single processing chamber 26. Figure 4 The second outlet port 25c of the bypass device 25 can be further associated with the common pipe 35.

[0133] The gas handling device 6 may further include at least one additional auxiliary pumping device 27 connected to at least one second outlet port 25c of the bypass device 25 and configured to reduce the pressure in the second outlet port 25c. Reducing the pressure in the second outlet port 25c makes it possible to decrease the rate of chemical reaction, which limits corrosion. Furthermore, this avoids explosive and flammable conditions for the gas. Deposits are reduced, thus requiring less maintenance.

[0134] The additional auxiliary pumping device 27 can be of any type. It includes, for example, a water jet pump and / or a Venturi gas jet pump and / or a liquid ring pump and / or a dry vacuum pump (e.g., a Roots, claw, and / or screw vacuum pump) and / or an impeller and / or a scroll and / or a diaphragm or membrane pump.

[0135] The outlet 30 of the auxiliary pumping device 27 is associated, for example, with the outlet 31 of the treatment chamber 26 to deliver gas to the central scrubber.

[0136] The gas handling device 6 may include a processing unit 32, which contains a controller, a microcontroller, a memory, and a computer program, such as a computer or a programmable logic controller. It may be the same unit as the control unit 17 of the vacuum line 4.

[0137] According to an exemplary embodiment, the gas processing device 6 includes a pressure sensor 28 configured to measure the pressure in a second outlet port 25c. A processing unit 32 may be connected to the pressure sensor 28 and configured to generate an alarm when the measurement from the pressure sensor 28 exceeds a predetermined threshold. The predetermined threshold is, for example, the measurement from the pressure sensor 28 under optimal operating conditions, such as a measurement taken immediately after cleaning and maintenance. Exceeding the threshold may reflect an abnormal increase in pressure in the second outlet port 25c, for example, due to pipe blockage and / or leakage.

[0138] Similarly, the processing unit 32 may be connected to the pressure sensor 16 at the discharge port 8 of the coarse pumping device 10 and configured to generate an alarm when the measurement value from the pressure sensor 16 exceeds a predetermined threshold in order to prevent blockage and / or leakage in the discharge pipe 7 connected to the inlet port 25a.

[0139] When several (at least two) bypass devices 25 are connected to the processing chamber 26, the processing unit 32 can be configured to identify the discharge pipe 7 connected to the inlet port 25a that has leaked or become blocked.

[0140] For this purpose, the gas processing device 6 includes at least two isolation valves 33 arranged at the corresponding discharge ports 8 of the coarse pumping device 10 connected to the inlet port 25a, and also includes at least two isolation valves 34 arranged at the corresponding inlets of the coarse pumping device 10.

[0141] Isolation valves 33 are normally open, meaning they are open in the absence of a signal or in the event of a malfunction. Furthermore, they can be controlled to close only when untreated gas is introduced into the treatment chamber 3.

[0142] The processing unit 32 is connected to the pressure sensor 16 of the isolation valve 33, the isolation valve 34 (if applicable), and the discharge port 8 of the coarse pumping device 10. The pressure sensor 16 is located downstream of the respective isolation valve 33.

[0143] In normal operating mode, isolation valves 33 and 34 are open.

[0144] In diagnostic mode, processing unit 32 controls all isolation valves 33 to close for a predetermined period of time, such as several minutes, except for one isolation valve on the discharge pipe 7 whose integrity will be checked.

[0145] The processing unit 32 can also control the closure of the upstream isolation valve 34 and / or the cessation and / or closure of the purge gas to the coarse pumping device 10.

[0146] The processing unit 32 compares the measurement from the pressure sensor 16 of the discharge pipe 7, which is open through its isolation valve 33, with a predetermined threshold. As previously stated, the predetermined threshold is, for example, the measurement value from the pressure sensor 16, obtained under the same operating conditions after cleaning and maintenance. When the measurement value from the pressure sensor 16 exceeds the predetermined threshold, the processing unit 32 generates an alarm. This test is then repeated for each discharge pipe 7. Thus, it is possible to identify which of the several discharge pipes 7 is faulty.

[0147] According to one embodiment, the gas processing device 6 includes at least one neutral gas injection device 29 configured to inject a neutral gas, such as nitrogen, into an auxiliary pumping device 27 and / or into the outlet 30 of the auxiliary pumping device 27. The neutral gas may dilute the pumped gas away from flammable or explosive conditions.

[0148] The neutral gas can be heated to, for example, over 50°C, or even over 500°C, before injection, for example, by passing it through a heat exchanger in contact with the hot part of the processing chamber 26. For example, if the auxiliary pumping device 27 includes a dry vacuum pump, the neutral gas injection device 29 can be formed by the purge gas of that dry vacuum pump. If the auxiliary pumping device 27 includes a Venturi gas jet pump, the neutral gas injection device 29 can be formed by the drive gas.

[0149] The auxiliary pumping device 27 can operate continuously.

[0150] According to another example, the additional auxiliary pumping device 27 is activated, for example, when at least one control element of the bypass device 25 places the inlet port 25a in communication with the second outlet port 25c, bypassing the processing chamber 26; and / or according to the measurements from the pressure sensor 28 and / or the combustible gas sensor arranged in the common pipe 35 connected to the second outlet port 25c and / or changes in information items from the processing chamber 3.

[0151] The processing unit 32 can be configured to control the pumping speed of the additional auxiliary pumping device 27 based on the number of bypass devices 25 that connect the inlet port 25a to the common pipe 35 connected to the second outlet port 25c.

[0152] For example, there are at least two separate pumping speeds: at least one first speed and one second speed, where the second speed is higher than the first speed.

[0153] In the case of the dry vacuum pump type auxiliary pumping device 27, the second pumping speed is obtained at a speed that is, for example, at least 20% or even at least 50% higher than the rotational speed that determines the first pumping speed.

[0154] This configuration can potentially save energy (or, in the case of an ejector pump, save drive gas) when very little pumped gas is passing through at least one second outlet port 25c.

[0155] The processing unit 32 is configured, for example, to control the pumping speed to a first speed when no control member connects the inlet port 25a to the second outlet port 25c; and to control the pumping speed to a second speed when at least one control member connects the inlet port 25a to the second outlet port 25c.

[0156] According to another example, the processing unit 32 may be configured to control the pumping speed of the auxiliary pumping device 27 to a first speed when at least one measurement value from the pressure sensor 16 at the discharge port 8 of the coarse pumping device 10 is below or equal to a predetermined threshold, and to control it to a second speed when the measurement value exceeds the threshold.

[0157] According to another example, the processing unit 32 is configured to control the pumping speed of the auxiliary pumping device 27 to a first speed when the concentration of the combustible gas or the gas that can cause deposition is below or equal to a predetermined threshold, and to control it to a second speed, which is higher than the first speed, when the concentration of the combustible gas or the gas that can cause deposition exceeds the threshold.

[0158] The concentration of combustible gas or gas capable of causing deposition is obtained, for example, by a gas sensor or information from the processing chamber 3, particularly information defined by the process formulation. When the concentration of combustible gas or gas capable of causing deposition increases, the processing unit 32 increases the pumping speed.

Claims

1. A gas treatment device (6) configured to treat a gas pumped by at least one rough pumping device (10) at atmospheric pressure, the gas treatment device (6) comprising a treatment chamber (26) and at least one exhaust pipe (7) configured to connect a discharge opening (8) of the at least one rough pumping device (10) to an inlet (9) of the treatment chamber (26), characterized in that, The gas processing device (6) further includes at least one auxiliary pumping device (13) configured to reduce the pressure in the at least one discharge pipe (7), said at least one auxiliary pumping device being located less than 1 meter from the inlet (9) of the processing chamber (26). The discharge pipe (7) has a length of one to four meters between the output of the coarse pumping unit (10) and the inlet (9) of the treatment chamber (26). The pumping capacity of the auxiliary pumping device (13) is smaller than that of the coarse pumping device (10). Reducing the pressure in the discharge line ensures the safety of the vacuum pipeline and prevents condensable substances from depositing in the discharge line and pumping unit. A first pressure sensor (16) is arranged on the discharge port (8) of the coarse pumping device (10). The dilution gas injection device (15) is configured to inject dilution gas into the discharge pipe (7) and / or the coarse pumping device (10) and / or the auxiliary pumping device (13); The control unit (17) is configured to control the auxiliary pumping device (13) and the dilution gas injection device (15) based on the pressure change measured by the first pressure sensor (16).

2. The gas treatment device (6) according to claim 1, characterized in that The auxiliary pumping device (13) is installed in the processing chamber (26).

3. The gas processing device (6) according to claim 1 or 2, characterized in that, The auxiliary pumping device (13) includes a Venturi gas injection pump, which is installed in the head of the burner (23) of the processing chamber (26).

4. The gas processing apparatus (6) according to claim 1 or 2, characterized in that, It includes at least one bypass device (25) inserted between the discharge pipe (7) and the auxiliary pumping device (13), the bypass device comprising: - Inlet port (25a), which is connected to the discharge pipe (7). - The first outlet port (25b) is connected to the auxiliary pumping device (13) connected to the processing chamber (26). - A second exit port (25c), configured to bypass the processing chamber (26), and - A control component configured to connect the inlet port (25a) to the first outlet port (25b) or to the second outlet port (25c).

5. The gas processing device (6) according to claim 4, characterized in that, The bypass device (25) is a controllable three-way valve.

6. The gas processing apparatus (6) according to claim 4, comprising at least two bypass devices (25), wherein the first outlet ports (25b) of the at least two bypass devices are connected to the processing chamber (26) via an auxiliary pumping device (13), characterized in that, The gas processing device includes: - At least two isolation valves (33) are arranged on the corresponding discharge ports (8) of the coarse pumping unit (10). - A processing unit (32) connected to the isolation valve (33) and a first pressure sensor (16) downstream of the isolation valve (33) is configured to control all isolation valves (33) except one isolation valve to close for a predetermined period of time, thereby generating an alarm when the measurement value of the first pressure sensor (16) from the discharge pipe (7) opened by its isolation valve (33) exceeds a predetermined threshold.

7. The gas processing device (6) according to claim 4, characterized in that, It includes at least one additional auxiliary pumping device (27) connected to at least one second outlet port (25c) of the bypass device (25) and configured to reduce the pressure in the second outlet port (25c).

8. The gas processing apparatus (6) according to claim 7, characterized in that, It includes: - A second pressure sensor (28), configured to measure the pressure in the second outlet port (25c), and - A processing unit (32) is connected to the second pressure sensor (28) and configured to generate an alarm when the pressure measurement exceeds a predetermined threshold.

9. The gas processing apparatus (6) according to claim 7, characterized in that, It includes at least one neutral gas injection device (29) configured to inject neutral gas into the additional auxiliary pumping device (27) and / or inject it at the outlet (30) of the additional auxiliary pumping device (27).

10. The gas processing apparatus (6) according to claim 7, characterized in that, It includes a processing unit (32) configured to control the pumping speed of an additional auxiliary pumping device (27) so that... - When no control component connects the inlet port (25a) to the second outlet port (25c), the pumping speed reaches the first speed, and - When at least one control element connects the inlet port (25a) to the second outlet port (25c), the pumping speed reaches a second speed, which is higher than the first speed.

11. The gas processing apparatus (6) according to claim 7, characterized in that, It includes a processing unit (32) configured to control the pumping speed of an additional auxiliary pumping device (27) so as to: - When at least one measurement value from the first pressure sensor (16) at the discharge port (8) of the coarse pumping device (10) is lower than or equal to a threshold, the pumping speed reaches a first speed, and - When the measured value exceeds the threshold, the pumping speed is increased to a second speed, which is higher than the first speed.

12. The gas processing apparatus (6) according to claim 7, characterized in that, It includes a processing unit (32) configured to control the pumping speed of an additional auxiliary pumping device (27) so as to: - When the concentration of combustible gas or gas that can cause deposition is below or equal to a predetermined threshold, the pumping speed reaches a first speed, and - When the concentration of combustible gas or gas that can cause deposition exceeds the threshold, the pumping speed is increased to a second speed, which is higher than the first speed.

13. The gas processing apparatus (6) according to claim 7, characterized in that, The additional auxiliary pumping device (27) includes a water jet pump and / or a Venturi gas jet pump and / or a liquid ring pump and / or a dry vacuum pump and / or an impeller pump.

14. The gas processing apparatus (6) according to claim 7, characterized in that, It includes a bypass pipe (14) configured to bypass the additional auxiliary pumping device (27) in the event of overpressure.

15. The gas processing apparatus (6) according to claim 1 or 2, characterized in that, The auxiliary pumping device (13) includes a water jet pump and / or a Venturi gas jet pump and / or a liquid ring pump and / or a dry vacuum pump and / or an impeller pump.

16. The gas processing apparatus (6) according to claim 1 or 2, characterized in that, The treatment chamber (26) includes a burner (23) and / or an electrical system and / or a plasma and / or a scrubber (24) and / or a chemical adsorption cartridge and / or a physical adsorption cartridge.

17. The gas processing apparatus (6) according to claim 1 or 2, characterized in that, The auxiliary pumping device (13) includes a Venturi gas injection pump, the driving gas of which includes fuel and / or combustion oxidizer and / or neutral gas.

18. The gas processing apparatus (6) according to claim 17, characterized in that, The Venturi gas jet pump includes a heating element configured to heat the driving gas.

19. The gas processing apparatus (6) according to claim 1 or 2, characterized in that, It includes a bypass pipe (14) configured to bypass the auxiliary pumping device (13) in the event of overpressure.

20. The gas processing device (6) according to claim 1, characterized in that, The at least one auxiliary pumping device is located less than 50 cm from the entrance (9) of the processing chamber (26).

21. A vacuum pipeline (4), characterized in that: It includes at least one gas processing device (6) according to any one of claims 1-20.

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