JP5502318B2 - Device for preventing the propagation of the flame front - Google Patents

Abstract

Apparatus is described for inhibiting the propagation of a flame front ignited by a pumping mechanism drawing a waste stream from a process chamber. A combustion chamber comprises an inlet for receiving the waste stream exhaust from the pumping mechanism and means for generating a flame for burning a flammable component of the waste stream. A pressure detector detects a pressure at a location through which the waste stream is drawn by the pumping mechanism, and a flame detector detects the presence of a flame in th combustion chamber. A controller regulates the delivery of at least one process fluid to the process chamber if the detected pressure is greater than a pressure above which the flame front can be sustained by the waste stream, or if there is no flame present in the combustion chamber.

Description

  The present invention relates to an apparatus and method for preventing propagation of a flame front ignited by a pump mechanism that draws a waste stream from a processing chamber.

  As semiconductor processing becomes increasingly sophisticated, the fluids used in these processes become increasingly aggressive. Accompanying these processes is the risk that the atmosphere in the vacuum pump used to evacuate the process chamber may contain flammable gas reservoirs or, in extreme cases, become completely flammable. Increase. Conventionally, vacuum pumps have not been designed with such an environment in mind. Generally, a vacuum pump mechanism includes a metal rotor that cooperates with a metal stator to carry fluid from the inlet to the outlet of the vacuum pump. These components of the pump mechanism need to have close tolerances to prevent the drawn fluid from leaking back toward the vacuum pump inlet. In the vicinity of these two metal components, it is considered that a spark is generated by an arbitrary collision of the components, so that the basic property tends to be an ignition source. In view of the aggressive nature of the processing performed by these vacuum pumps, deformations of metal components (due to corrosion) are increasingly likely to reduce these tolerances significantly. Furthermore, the reaction of materials used in semiconductor processing often causes material deposition on the rotor and stator surfaces. Such deposition affects the alignment of the components of the pump mechanism and further narrows their gaps so that metal component collisions may occur.

  Detonation may occur when the flammable atmosphere comes in contact with the ignition site. If this detonation causes damage to the device, a safety issue is likely to arise. In the case of a monolithic and catastrophic collapse, a projectile from a vacuum pump component may result, and to any other equipment in the vicinity, and ultimately to any personnel located in the area A dangerous environment is created. If the collapse is not so sudden, a flammable gas leak will occur in the environment surrounding the device. If there are additional ignition sources in this area, there is a further risk of detonation. If damage is caused by detonation, it may be necessary to stop the operation of the entire pumping device to allow maintenance to begin. This results in downtime for the entire processing system and thus results in lost productivity.

  Therefore, it has traditionally been considered desirable to minimize the risk of such detonation occurring within a vacuum pump. For example, it is known to introduce a large amount of inert gas into a vacuum pump to dilute the combustible mixture in the pump in order to make the concentration of the combustible mixture well below the detonation lower limit of that particular mixture. It has been. In this way, it is considered that detonation in the vacuum pump can be prevented because no flammable environment is generated. However, if a significant amount of inert gas is introduced into the vacuum pump, the volume of both the vacuum pump and any removal system provided downstream thereof should be increased to accommodate the increased fluid volume. . In semiconductor processing equipment, space is at a premium, so it is desirable to avoid any increase in the capacity of such devices. There are also significant costs associated with installing and operating large capacity devices.

  Furthermore, unless the mixing between the flammable mixture and the inert gas is particularly good, a pool or pool of flammable gases can form in the vacuum pump. This is particularly likely when an inert gas is introduced on the way from the vacuum pump downstream to avoid pressure fluctuations in the upstream processing chamber. In this approach, some of the inert gas will be routed back toward the process chamber to achieve some dilution in the low pressure region, but in order to achieve an appropriate dilution level, the amount is inadequate. Satisfactory, in other words, the mixture (or at least the mixture pool) may remain within the flammable range.

  An object of at least a preferred embodiment of the present invention is to seek a solution to these and other problems.

  In accordance with one aspect of the present invention, an apparatus for preventing propagation of a flame front ignited by a pump mechanism of a vacuum pump apparatus that draws a waste stream from a processing chamber, wherein the waste stream is drawn by the pump mechanism Means for detecting pressure, the flame front being sustained by the waste stream at a pressure higher than a constant pressure, and further when the detected pressure is greater than the constant pressure, to the processing chamber An apparatus is provided that includes means for regulating the delivery of at least one processing fluid.

  The apparatus may further include a forward line for conveying the waste stream from the processing chamber to the pump mechanism. The means for detecting may be arranged to be configured to detect pressure in the front piping.

  The means for regulating may include at least one shut-off valve for preventing delivery of at least one processing fluid to the processing chamber. The means for regulating may include a controller for receiving a signal indicating the detected pressure. The shut-off valve may be controlled by a controller.

  The vacuum pump device may have another pump mechanism located upstream of the pump mechanism. This alternative pump mechanism is preferably constituted by a booster pump, for example a roots blower.

  Means for cooling the waste stream may be provided between the processing chamber and the pump mechanism. The booster pump described above may serve as a cooling mechanism. As a variant, it may be provided as a separate function, especially when the requirements for additional pump capacity are minimal. The means for cooling may include an internal cooling mechanism located in the forward piping, such as one or more cooling baffles, one or more cooling fingers, and / or one or more cooling. It is good to have a coil. As a variant, the means for cooling may comprise an external cooling mechanism, for example a Peltier device and / or a cooling coil, located adjacent to the outer surface of the front pipe.

  The device may have a discharge pipe connected to the discharge part of the vacuum pump device. The exhaust pipe should be configured to prevent deflagrations generated therein from developing into detonations. The drain tube may be one or more detonation barriers, one or more purge ports, one or more parts of various diameters, and one or more of various orientations It is preferable to have at least one of a group of parts.

  Depending on the detected pressure, means may be provided for delivering an inert gas into the waste stream. The means for delivering the inert gas may include at least one purge port located within the stator of the pump mechanism, the purge port being a waste stream effluent discharged from the pump mechanism. It is good to arrange | position so that an inert gas may be introduce | transduced into. The means for delivering the inert gas may comprise a heating means configured to heat the purge gas prior to delivery of the purge gas.

  The apparatus may have a removal device for receiving the waste stream discharged from the pump mechanism. The removal device has a combustion chamber that may have an inlet for receiving waste stream effluent discharged from the pump mechanism. The combustion chamber may also have means for generating a flame therein for burning the combustible components of the waste stream. If the chamber is so configured, the removal device may have means for detecting the presence of a flame in the combustion chamber.

  The means for regulating may be configured to regulate delivery of at least one processing fluid to the processing chamber when no flame is detected in the combustion chamber. Means may be provided for delivering an inert gas into the waste stream exhaust discharged from the pump mechanism when no flame is detected in the combustion chamber.

  The inlet of the combustion chamber may be configured so that flames from the combustion chamber do not propagate into the waste stream upstream of the combustion chamber.

  The means for regulating may depend not only on the pressure in the inlet region of the vacuum pump, but also on the presence of a flame in the combustion chamber. Accordingly, in accordance with another aspect of the present invention, an apparatus for preventing the propagation of a flame front ignited by a pump mechanism that draws a waste stream from a processing chamber, comprising a combustion chamber, the combustion chamber comprising a pump Having an inlet for receiving the waste stream discharged from the mechanism and means for generating a flame for burning the combustible components of the waste stream; Means for detecting the pressure at the point where it is drawn and means for detecting the presence of a flame in the combustion chamber, the front of the flame being sustained by the waste stream at a pressure above a certain pressure. In addition, when the detected pressure is greater than the constant pressure or when there is no flame in the combustion chamber, a small amount to the processing chamber Having means for regulating the delivery of Kutomo one process fluid, provides an apparatus.

  Feed regulation may depend solely on the presence of a flame in a combustion chamber positioned downstream of the pump mechanism. Accordingly, in accordance with another aspect of the present invention, an apparatus for preventing the propagation of a flame front ignited by a pump mechanism that draws a waste stream from a processing chamber, comprising a combustion chamber, the combustion chamber comprising a pump An inlet for receiving waste stream exhaust discharged from the mechanism; means for generating a flame for burning the combustible components of the waste stream; and the presence of a flame in the combustion chamber And a means for regulating delivery of at least one processing fluid to the processing chamber when no flame is present in the combustion chamber.

  In accordance with another aspect of the present invention, a method for preventing propagation of a flame front ignited by a pump mechanism that draws a waste stream from a processing chamber, wherein the pressure at the point where the waste stream is pulled by the pump mechanism is detected. The flame front is sustained by the waste stream at a pressure higher than a constant pressure, and further, when the detected pressure is greater than the constant pressure, at least one processing fluid to the processing chamber A method is provided that includes the step of regulating delivery.

  In accordance with another aspect of the present invention, a method for preventing propagation of a flame front ignited by a pump mechanism that draws a waste stream from a processing chamber, the combustion for receiving the waste stream exhaust discharged from the pump mechanism Detecting the presence of a flame in the chamber and regulating the delivery of at least one processing fluid to the processing chamber when no flame is present in the combustion chamber.

  In accordance with another aspect of the present invention, a method for preventing the propagation of a flame front ignited by a pump mechanism of a vacuum pump that draws a waste stream from a processing chamber and detecting the presence of a purge gas flow in the vacuum pump And a method of regulating delivery of at least one processing fluid to the processing chamber when purge gas is not being delivered.

  In accordance with another aspect of the present invention, a processing chamber supplied with at least one processing fluid from an inlet and a vacuum pump connected through a forward line to the outlet of the processing chamber to draw a waste stream from the processing chamber A method of initiating operation of a processing system having an apparatus and a detector for detecting a faulty condition of the processing system, the step of switching on the system and ensuring that the detector is operating Detecting a first status signal indicative of a faulty state of the system from the detector, subsequently initiating operation of the vacuum pump device, and a second status signal indicative of the operating status of the system And subsequently initiating delivery of processing fluid to the processing chamber to initiate processing in the processing chamber.

  Features described above in connection with the apparatus of the system aspect of the present invention are equally applicable to the method aspect and vice versa.

  Potential damage that may be caused by explosions in or incidental to the vacuum pump as described above by providing pressure sensing means and / or flame detectors and relying on them for supply from combustible material sources Can be reduced and prevented, thus making it possible to draw the combustible mixture with an improved safety level.

  Rather than trying to prevent any flammable mixture from occurring, it introduces various features that prevent the development of any deflagration that might occur, and thus prevent or at least limit possible damage caused thereby. . For this reason, it is not necessary to increase the capacity and the consumable materials associated therewith, all can be achieved using standard capacity equipment. As a result, expenses associated with installing and operating such a device can be reduced.

  In known pump devices where it is recognized that ignition may occur, conventional flame arresters are typically installed at the inlet and / or outlet of the vacuum pump. However, such a device generally causes a decrease in conductance value and a decrease in pump efficiency. This is particularly noticeable when used in processes that generate deposit-forming particulate matter such as is often found in semiconductor processing. As deposits form in the flame arrester, the open cross-sectional area through which the drawn fluid can pass is significantly reduced, thus further reducing conductance. Therefore, it is inappropriate to use flame arresters in such situations where frequent inspection and maintenance should be avoided.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 illustrates a processing chamber 10 having at least one fluid inlet 20 that is used to process a sample such as a semiconductor wafer or flat panel display device contained within the processing chamber 10. For introducing one or more processing fluids, typically gases. A shutoff valve 25 is provided at the fluid inlet 20 to selectively shut off the flow of fluid to the processing chamber 10. An outlet from the processing chamber 10 is connected to an inlet of the vacuum pump 30 via a front pipe 40, and the vacuum pump 30 has a pump mechanism suitable for drawing a waste stream from the processing chamber 10. In order to detect the pressure of the waste stream drawn from the vacuum pump 30, a pressure detector 45 is provided in the front pipe 40 (shown) or at the inlet of the pump 30 for determining the local pressure in that region. A signal indicating the front pipe pressure is output from the pressure detector 45 to the controller 50.

  The discharge of the vacuum pump 30 is then connected to the inlet of the reduction or removal system 55 via the tube 60. The purpose of removal is to more conveniently dispose of one or more chemical species of the waste stream, for example by a scrubber connected to a discharge conduit 70 for conveying the waste stream from the exit of the removal system. Or converting the chemical species into one or more different compounds that can be safely discharged to the atmosphere through the discharge conduit 70. In this example, a bypass line 80 is provided to connect the tube 60 directly to the discharge conduit 70, thereby bypassing the removal device 55 and prior to processing in the processing chamber 10 and between processes. For a period of time, it is possible to have the removal device 55 wait or even be stopped, thus reducing costs. A three-way valve 90 for controlling whether the flow path from the waste stream passes through the removal system 55, or whether it is diverted to pass through the bypass pipe 80, is connected to the bypass pipe 80 and the pipe. 60 at the junction between the two. The operation of the three-way valve 90 is controlled by the controller 50.

  As illustrated in FIG. 1, a purge system 75 for introducing a large amount of inert gas into the vacuum pump 30 may be provided. The purge system 75 typically includes one or more purge ports located along the length of the vacuum pump 30. Here, a further purge port 65 for introducing an inert gas downstream of the vacuum pump 30 may be arranged in the tube 60, preferably between the outlet of the vacuum pump 30 and the valve 90. Preferably, means are provided in the purge system 75 for detecting the flow rate of the purge gas into the vacuum pump 30 and / or the tube 60.

  In this embodiment, the removal system 55 has a combustion chamber in which combustion of any combustible component of the waste stream occurs. A flame detector 95 is provided in the removal system 55 for sensing whether a flame is present in the combustion chamber. A signal instructing this state is output from the flame detector 95 to the controller 50.

  When the combustible mixture is introduced into the processing chamber 10 via the fluid inlet 20, or the combustible mixture is generated in the processing chamber 10 by a process performed on a sample disposed in the processing chamber 10. In some cases, the waste stream may contain a combustible mixture. As a result, a combustible atmosphere is generated in the pump 30. To confirm that a typical vacuum pump 30 (BOC Edwards iH160F pump) is capable of withstanding an initial internal explosion due to ignition of the flammable material region, a test was performed on this pump. These tests have shown that the pump can withstand twice the pressure load of the peak pressure encountered in deflagration starting when it is filled with a stoichiometric flammable mixture under operating conditions.

  The conditions in the vacuum pump 30 should be such that deflagration can occur when an ignition source is present. When a flame front is generated by such deflagration, the flame front propagates through the combustible atmosphere away from the ignition source. The conditions encountered by the flame front affect how the flame propagation proceeds.

  For example, if the flame front propagates upstream into the forward piping 40, the flame front encounters a low pressure region. There is a critical pressure in the majority of combustible mixtures, and at pressures below this critical pressure, the combustible mixture does not burn. For most flammable mixtures, this critical pressure is around 60 mbar (6 MPa), but for some flammable mixtures, it may be as low as 1 mbar (0.1 MPa). During use of the processing chamber 10, the pressure in the front piping 40 of the vacuum pump 30 is generally maintained below this critical pressure. If the flame front encounters this low pressure region, the flame front cannot be sustained and the flame is extinguished.

  As the flame front propagates downstream from the pump 30, the flame front advances downstream through the tube 60 and into the removal system 55. As described above, the flame in the combustion chamber of the removal system 55 ignites any flammable fluid that enters the combustion chamber so that the waste stream discharged from the removal system 55 has only a small flammable component. Does not contain, preferably does not contain flammable components. As a result, when the flame front propagates to the removal system 55, there is no burning fuel left, so the combustion chamber substantially acts as a flame arrester, thereby preventing further propagation of the flame front. The flame is extinguished.

  Alternatively, an inert gas may be introduced from the purge port 65 into the tube 60 if the removal system 55 is not provided or in addition to the removal system 55. This inert gas dilutes the combustible mixture to a concentration lower than that represented by the lower combustion limit, thereby forming an incombustible atmosphere. Therefore, when the flame front propagates downstream of the vacuum pump 30, the flame front enters the non-flammable atmosphere in the tube 60 and is extinguished.

  In normal operation of the device, the range of flame front propagation is limited by the extinction effect of the features described above. However, in order to achieve a safer system, it is desirable to implement one or more of the following safety devices.

  As described above, the pressure detector 45 is provided in the front pipe 40 or the inlet of the vacuum pump 30. The pressure detector 45 outputs a signal indicating its local pressure to the controller 50, which is a critical value required to sustain a predetermined value, generally the flame front as described above. In order to ensure that the local pressure stays lower than this, the local pressure in this region is detected. If this predetermined pressure is exceeded, there is a risk that the flame front will persist in the front pipe 40. In addition, if the flame in the combustion chamber of the removal system 55 is extinguished for any reason, the combustible component of the waste stream will not be ignited, and therefore a combustible atmosphere will be maintained. This flammable atmosphere can sustain a flame front that propagates through the removal system 55 into the exhaust conduit 70. As described above, the flame detector 95 outputs a signal for confirming the presence of the flame to the controller 50.

  As also described above, a valve 25 is provided at the inlet 20 of the processing chamber 10 to allow the introduction of at least one processing fluid into the processing chamber 10 as needed. The operation of the valve 25 is controlled by the controller 50. When the pressure in the front pipe 40 exceeds a predetermined pressure and the flame in the combustion chamber is extinguished, or when the purge gas delivery to the vacuum pump 30 is interrupted, the controller 50 turns the valve 25 on. A signal to close is output to the valve 25, thereby stopping the flow of processing fluid to the processing chamber 10. By blocking the flow of these fluids, the concentration of the combustible mixture in the apparatus downstream from the processing chamber 10 is rapidly lowered below the lower explosion limit of the combustible mixture, reducing the risk of deflagration.

  In addition to shutting off the flammable fluid source, the controller 50 can take yet another removal action in the form of a command to the purge system 75 to fill the vacuum pump 30 with an inert gas, thereby providing a vacuum. The combustible mixture concentration in the pump 30 is reduced more rapidly. Such a purge may be delivered from the processing chamber 10 to any portion of the equipment downstream, but is typically one of several standard purge ports formed in the pump stator. May be delivered directly to the vacuum pump 30 or may be delivered directly into the tube 60 via a purge port 65 extending from the discharge of the vacuum pump 30.

  In addition to the reduction measures described above, other safety devices may be introduced. For example, the controller 50 may control the three-way valve 90 so as to close the bypass pipe 80 when the shutoff valve 25 is open. In other words, the bypass line is closed so that fluid must pass through the removal system 55 when there is any possibility that a combustible mixture is present in the device.

  Alternatively, if the shut-off valve 25 is in the open position so that a combustible mixture can be expected to exist downstream of the processing chamber 10, the controller 50 delivers inert gas from the purge port 65. The purge system 75 is instructed to cause the combustible mixture concentration in the tube 60 to fall below the lower combustion limit so that no incident flame front can be sustained in this region.

  If the flame front propagates along a sufficiently long path under appropriate conditions where detonation can occur, a significant increase in the level of damage to equipment and peripheral equipment occurs. Such a long path can be seen in the form of a tube 60 extending between the vacuum pump 30 and the removal system 55. For this reason, the tube 60 extending from the vacuum pump 30 is preferably designed so that it suppresses detonation. Factors that affect this behavior are the diameter of the tube 60, the length of any straight portion of the tube 60, and the presence of any obstacles in the tube 60 commonly referred to as detonation barriers.

  In some environments, the combustible waste stream contains condensable combustible gases. Tube 60 has a higher pressure and lower temperature environment than that found in the upstream portion of the apparatus, and thus has particularly suitable conditions for condensation to occur. Where pools or pools of flammable liquid actually occur, these constitute an unexpected source of flammable material. The release rate of the combustible material from the reservoir depends on the evaporation rate of the combustible liquid into the ambient atmosphere, which is the pressure and temperature of the region, the content of any fluid present in the gaseous form and Depends on a number of factors such as saturation level.

  Yet another problem associated with condensable combustible materials is that if a fully gaseous mixture can be expected to pass through the device in the expected manner, a pool of condensate will accumulate in the device. It may stay much longer. In some cases, the various processing steps performed in the processing chamber may use materials that cannot coexist. If the fluid is gaseous, it may be possible to discretize the processing stage so that there is some certainty that the waste stream has been removed from the system before one stage is finished and the next stage begins. Good. However, if there is a pool of flammable liquid that continues to evaporate in the tube 60, there will still be a pool of flammable liquid when the next stage of processing begins so that there are materials that cannot coexist. Allow mixing in tube 60 and reacting in contact. A specific example of this is that when a treatment stage is followed by a washing stage and a combustible mixture and a material having a particularly high oxide content are mixed, the mixture of these materials is particularly reactive. There is a high possibility.

  Therefore, it is desirable to first avoid the formation of such condensate, and therefore, in a variant, heating may be used to prevent the formation of cold spots that may promote fluid condensation. Elements may be provided around the tube 60. Thus, the fluid discharged from the vacuum pump 30 can be maintained in a gas form. In order to further avoid the formation of condensate in the vacuum pump 30 and the tube 60, any purge gas to be delivered via the purge system 75 is preferably heated prior to delivery. In this way, the waste stream avoids unnecessary cooling, which further helps to avoid the formation of condensate. In an apparatus configured to heat the purge gas, a sensor for detecting the purge gas temperature is preferably provided. In situations where the purge gas temperature is lower than a predetermined value, the sensor generates a signal. By operating the shutoff valve 25 in response to this signal, the flow of the processing fluid into the processing chamber 10 can be terminated.

  FIG. 2 illustrates how the vacuum pump 30 and removal system 55 can be used to prevent any flammable fluid leaking from the device enclosure 100 from contacting an external ignition source and causing deflagration. It is illustrated whether it is accommodated in the inside. The environment within the enclosure 100 can be controlled by forced extraction. As illustrated, yet another detection unit for detecting the rate of fluid extraction from the enclosure, namely the flow detector 105, is incorporated into the extraction duct 110 of the enclosure. A signal indicating the extraction flow rate is output from the flow rate detector 105 to the controller 50. The controller 50 monitors the extraction flow rate and initiates the above-described procedure when the extraction flow rate drops below a predetermined value during operation of the processing chamber 10.

The table below summarizes some of the various removal procedures that can be performed.

  The controller 50 may be replaced by a wired connection between each of the detection components 45, 95, 105 and each of the valve components 25, 65, 90. Since the detection and valve components are safety-critical components, they are provided in a dual safety device configuration and / or the functions of these components overlap within the configuration. Redundancy is provided.

  In any of the above embodiments having a removal system 55 with a combustion chamber, additional safety devices may be implemented, as illustrated in FIG. As mentioned above, any combustible component of the waste stream is incinerated when in contact with the flame created in the combustion chamber, thereby creating a non-flammable atmosphere. However, there is a risk that the flame front comes out of the entrance to the combustion chamber and propagates into the tube 60 as soon as the flame comes into contact with the combustible atmosphere. This is generally called “backfire”. Since it is desirable to prevent flashback from occurring, a modified inlet that provides a limit to the incoming waste stream may be provided, thereby increasing the speed of the incoming waste stream. If the inflow is large enough, the flame front initiated in the combustion chamber is restrained at a point with a suitable opening that serves to hold the flame front. One example of such a device is a thin-walled metal cone 120 located at the inlet of the combustion chamber, as illustrated in FIG. If the flame front stays in a small opening, the cone temperature will rise rapidly in the direction of increasing diameter. By providing a thermal sensor on the cone, the backfire can be detected early and the removal procedure can be implemented as described in detail above.

  As mentioned above, in some mixtures, such as those having a high hydrogen content in the presence of oxygen, the critical pressure can be as low as 10 mbar (1 Mpa). In such a situation, it is necessary to supplement the pump capacity of the vacuum pump 30 to ensure that the pressure does not exceed the critical pressure. As a modification, the thermal environment may be changed so that the critical pressure value increases.

  FIG. 4 illustrates a third embodiment, which has another vacuum pump 130, such as a booster pump, provided in series with the vacuum pump 30 and connected to it by a conduit. The booster pump preferably has a Roots pump mechanism. An additional pressure detector 145 is positioned in the conduit to allow another indication of the status of each of the vacuum pumps 30, 130 to be supplied to the controller 50.

  The introduction of another vacuum pump 130 not only potentially lowers the pressure in the forward piping 40 but also serves to extinguish the waste stream drawn from the processing chamber 10. Extinguishing cools the waste stream, thereby increasing the critical pressure value, the lower limit at which propagation of the flame front is not sustained. Further, when the flame front propagates upstream from the pump mechanism and enters the booster pump 130, the quenching action is combined with a restriction on the flow as given by the tight tolerances of the booster pump, thereby making the booster pump 130 a flame arrester. Acts essentially as an element.

  For some mixtures, extinguishing alone will reduce the critical pressure to the extent that a separate vacuum pump 130 is not required. In such situations, the extinguishing of the waste stream may be accomplished by other means either in the front piping or outside thereof. For example, a cooling baffle, a cooling finger, or a cooling coil may be provided inside the front pipe, or the outer surface of the front pipe may be cooled by using a cooling coil or a Peltier device.

  In connection with any of the embodiments described above, detectors 45, 95, 145 may be used to increase the safety of the pump startup procedure and subsequent processing performed in the processing chamber 10. The starting procedure is illustrated in the flowchart of FIG. With the power switch to the entire system turned on, the detectors 45, 95, 145 detect that the pressure upstream of the vacuum pumps 30, 130 exceeds a predetermined critical pressure and that there is a flame in the removal system 55. Recognize a bad state because it no longer exists. The vacuum pump 30 is not allowed to be started until a “bad” signal is received from each of these detectors indicating that each detector is functioning properly. If no "bad" status signal is received from each detector, it is assumed that at least one of the detectors is defective and the vacuum pump is prevented from starting.

  With the vacuum pump 30 and removal system 55 activated and normal operating conditions established, each of the detectors should recognize a non-defective or operational condition. Once the ready state is established throughout, the process can begin. As described above, if any one of the detectors 45, 95, and 145 indicates a “defective” state thereafter, the process is performed by operating the shut-off valve 25 to perform one or more processes on the process chamber 10. It is terminated by stopping the fluid delivery.

1 is a schematic view of a first embodiment of an apparatus for preventing propagation of a flame front ignited by a pump mechanism that draws a waste stream from a processing chamber; FIG. FIG. 5 is a diagram of a second embodiment of an apparatus for preventing propagation of a flame front ignited by a pump mechanism that draws a waste stream from a processing chamber. 2 is a detailed view of an inlet to a combustion chamber for use with the apparatus of FIG. FIG. 6 illustrates a third embodiment of an apparatus for preventing propagation of a flame front ignited by a pump mechanism that draws a waste stream from a processing chamber. FIG. 6 is a flow chart illustrating a starting system associated with any of the embodiments described above that can accommodate two types of failures.

Claims (22)

An apparatus for preventing propagation of a flame front ignited by a pump mechanism of a vacuum pump apparatus that draws a waste stream from a processing chamber,
Means for detecting pressure at a location where a waste stream is drawn by the pump mechanism;
Detected pressure is, when higher than the pressure which is to sustain the flame front by the waste stream, have a means for regulating the delivery of at least one processing fluid to the processing chamber,
The means for regulating comprises at least one shut-off valve for preventing delivery of at least one processing fluid to the processing chamber and a controller for receiving a signal indicative of the detected pressure. The shut-off valve is controlled by the controller, which causes the shut-off valve to close when the detected pressure is higher than the pressure maintained by the waste stream on the flame front; apparatus.   The apparatus according to claim 1, wherein the vacuum pump device has another pump mechanism located upstream of the pump mechanism. Furthermore, with a booster pump located upstream of the pump mechanism, according to claim 1 or 2. 4. The apparatus of any one of claims 1-3 , further comprising means for cooling a waste stream between the processing chamber and the pump mechanism. The apparatus of claim 4 , wherein the means for cooling comprises a booster pump. 6. An apparatus according to claim 4 or 5 , wherein the means for cooling comprises an internal cooling mechanism located in the front pipe. The internal cooling mechanism may be one or more of a group consisting of one or more cooling baffles, one or more cooling fingers, and one or more cooling coils. The apparatus according to claim 6 . The apparatus according to any one of claims 4 to 7 , wherein the means for cooling includes an external cooling mechanism located adjacent to an outer surface of the front pipe. The apparatus according to claim 8 , wherein the external cooling mechanism is one or both of a Peltier device and a cooling coil. Furthermore, it has a discharge pipe connected to the discharge part of the said vacuum pump apparatus, The said discharge pipe is comprised so that the deflagration which generate | occur | produced may be prevented from developing into a detonation. 10. The apparatus according to any one of items 9. The drain tube may include one or more detonation barriers, one or more purge ports, one or more parts of various diameters, and one or more of various orientations to have at least one of the group consisting of parts according to claim 10. Furthermore, in accordance with the detected pressure has a means for delivering the inert gas into the waste stream, apparatus according to any one of claims 1 to 11. The apparatus of claim 12 , wherein the means for delivering the inert gas comprises at least one purge port located within a stator of the pump mechanism. 14. A means according to claim 12 or 13 , wherein the means for delivering the inert gas comprises at least one purge port for introducing the inert gas into the waste stream effluent discharged from the pump mechanism. apparatus. 15. An apparatus according to any one of claims 12 to 14, wherein the means for delivering the inert gas comprises heating means configured to heat the purge gas prior to delivery of the purge gas. 16. Apparatus according to any one of the preceding claims, further comprising a removal device for receiving waste stream effluent discharged from the pump mechanism. The removal device has a combustion chamber that burns combustible components of the waste stream within the combustion chamber and an inlet for receiving the waste stream exhaust discharged from the pump mechanism. and means for generating a flame for apparatus according to claim 16. The apparatus of claim 17 , further comprising means for detecting the presence of a flame in the combustion chamber. The apparatus of claim 18 , wherein the means for regulating is configured to regulate delivery of at least one processing fluid to the processing chamber when no flame is detected in the combustion chamber. 20. An apparatus according to claim 18 or 19 , further comprising means for delivering an inert gas into the waste stream effluent discharged from the pump mechanism when no flame is detected in the combustion chamber. 21. The apparatus of any one of claims 16-20 , wherein the combustion chamber inlet is configured to prevent a flame from the combustion chamber from propagating into a waste stream upstream of the combustion chamber. A method for preventing propagation of a flame front ignited by a pump mechanism that draws a waste stream from a processing chamber, comprising:
Detecting pressure at a point where a waste stream is drawn by the pump mechanism;
Detected pressure is, when higher than the pressure which is to sustain the flame front by the waste stream, have a the steps of regulating the delivery of at least one processing fluid to the processing chamber,
In the regulating step,
At least one shut-off valve for blocking delivery of at least one type of processing fluid to the processing chamber is controlled by a controller for receiving a signal indicative of the detected pressure, the controller detecting the detected pressure Closing the shut-off valve when the pressure is higher than the pressure maintained by the waste stream on the flame front .

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