Patent Publication Number: US-2020292084-A1

Title: Gate valve for continuous tow processing

Description:
FIELD 
     Embodiments of the present disclosure generally relate to substrate processing equipment. 
     BACKGROUND 
     Within substrate processing equipment, a gate valve may be utilized, for example, in multi-chamber processing systems to selectively isolate or couple adjacent volumes. For example, current multi-chamber processing apparatus typically include semiconductor processing slit valves and gate valves to isolate pressure controlled processing volumes during transfer of work parts or repair of one or more fluidly connected processing regions. However, the inventors have observed that the seals and sealing surfaces of the conventional valves are limited in their sealing ability, especially if an interfering material such as a continuous substrate is present at the seal interface. Ineffective leak control is especially problematic in multiple processing volumes, when the process in each chamber uses a different pressure, or when only one of the processing volumes needs to be vented and cooled for service or due to emergency process stops. 
     Accordingly, the inventors have provided an improved gate valve. 
     SUMMARY 
     Embodiments of gate valves and methods for using same are provided herein. In some embodiments, a gate valve includes: a body; a plurality of seals disposed within the body and configured to move between a closed position and an open position; a plurality of volumes defined by the plurality of seals and the body; a gas inlet disposed through a first side of the body and fluidly coupled to an innermost one of the plurality of volumes; and a gas outlet disposed through a second side of the body opposite the first side and fluidly coupled to other ones of the plurality of volumes. 
     In some embodiments, a gate valve for processing a continuous substrate includes: a body having a first wall, a second wall opposite the first wall, an opening disposed from a first surface to an opposing second surface of the body, wherein the opening is configured to hold and convey a continuous substrate; a plurality of seals movably disposed between the first wall and the second wall, configured to move between a closed position to seal the opening, and an open position that reveals the opening; a plurality of volumes disposed between adjacent ones of the plurality of seals and defined by the plurality of seals and the body; a gas inlet disposed through a first side of the body and fluidly coupled to an innermost one of the plurality of volumes on the first side of the body, wherein the gas inlet fluidly coupled to an innermost one of the plurality of volumes; and a gas outlet disposed through a second side of the body opposite the first side and fluidly coupled to other ones of the plurality of volumes disposed on either side of the innermost one of the plurality of volumes. 
     In some embodiments, a processing system for processing a continuous substrate includes: a first chamber for processing a continuous substrate; a second chamber for processing the continuous substrate; and a gate valve coupling the first chamber to the second chamber and having an opening through which the continuous substrate can extend between the first chamber and the second chamber, wherein the gate valve is as described in any of the embodiments disclosed herein, and wherein a first side the body is coupled to the first chamber and a second side of the body is coupled to the second chamber. 
     In some embodiments, a method of processing a continuous substrate includes: processing a continuous substrate in at least one of a first process chamber or a second process chamber coupled to the first process chamber through a gate valve, wherein the continuous substrate is simultaneously disposed through each of the first process chamber, the gate valve, and the second process chamber; and closing the gate valve while the continuous substrate is disposed therethrough to substantially isolate the first process chamber from the second process chamber. 
     Other and further embodiments of the present disclosure are described below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present disclosure, briefly summarized above and discussed in greater detail below, can be understood by reference to the illustrative embodiments of the disclosure depicted in the appended drawings. However, the appended drawings illustrate only typical embodiments of the disclosure and are therefore not to be considered limiting of scope, for the disclosure may admit to other equally effective embodiments. 
         FIG. 1  depicts a schematic view of a multiple chamber reactor having a gate valve in accordance with at least some embodiments of the present disclosure. 
         FIG. 2A  depicts a schematic side view of a gate valve in an open position in accordance with at least some embodiments of the present disclosure. 
         FIG. 2B  depicts a schematic side view of the gate valve of  FIG. 2A  in a closed position in accordance with at least some embodiments of the present disclosure. 
         FIG. 3A  depicts a schematic side view of a gate valve in an open position in accordance with at least some embodiments of the present disclosure. 
         FIG. 3B  depicts a schematic side view of the gate valve of  FIG. 3A  in a closed position in accordance with at least some embodiments of the present disclosure. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The figures are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. 
     DETAILED DESCRIPTION 
     Embodiments of gate valves and methods for using same are provided herein. The disclosed gate valves and methods of using same advantageously benefit vacuum processing of continuous web, film, sheet, ribbon-like fiber and other thin or flat substrates. For some applications, maintaining a continuous substrate, without breaks or joints, across one or more sealing interfaces that correspond to one or more openings where material is transferred into or out of a processing volume is beneficial. Conventional semiconductor processing slit valves and gate valves are used for transferring discrete work parts into pressure controlled processing volumes. These conventional designs, and the seals and sealing surfaces specifically, are limited in their capacity to maintain adequate leak integrity if interfering material is present at the seal interface. For some applications such as chemical vapor infiltration of ceramic fibers, conveying one or more tow across multiple vacuum breaks such that the start of the tow (e.g., an untwisted bundle of continuous filaments) may be at atmospheric pressure, a middle section at reduced pressure, and the end of the tow at atmospheric pressure is advantageous. The foregoing arrangement allows the process to pause and for substrate loading adjustments, or repairs to be made without bringing the furnace to atmospheric pressure. The disclosed gate valve is capable of producing the pressure gradient without compromising the physical integrity of the continuous substrate at the sealing interface. Furthermore, keeping the furnace hot when the processing volumes are not in use is beneficial for system utilization and furnace component reliability. 
     The gate valves of the present disclosure may be used in any application in which a conventional gate valve may be used, for example in applications in which throttling the flow of a gas between two adjacent volumes is desirable or advantageous. In a non-limiting application, the disclosed gate valve may be disposed between chambers in a two process chamber system, or other suitable process chambers that require a gate valve. For example,  FIG. 1  depicts a schematic diagram of a two chamber system of the kind that may be used to practice embodiments of the disclosure as discussed herein. 
     The illustrative two process chamber system  100  includes a first chamber  110  (e.g., a process chamber) having a first chamber volume  114  within a first chamber body (wall  120 ). In some embodiments, a substrate feedthrough  150  may be provided for conveying a continuous substrate between the first chamber volume  114  and a volume disposed outside of the first chamber  110  (e.g., an adjacent process chamber, a substrate handler, or the like). The system  100  also includes a second chamber  130  (e.g., a process chamber) having a second chamber volume  134  within a second chamber body (wall  140 ). In some embodiments, a substrate feedthrough  170  may be provided for conveying the continuous substrate between the second chamber volume  134  and a volume disposed outside of the second chamber  130  (e.g., an adjacent process chamber, a substrate handler, or the like). First chamber  110  and second chamber  130  are selectively fluidly coupled to each other via a gate valve  102 . 
     In operation, a continuous substrate  154  is conveyed through substrate feedthroughs  150  and  170 , via an opening  106  of the gate valve. The continuous substrate  154  may be processed in the first chamber volume  114  at a first chamber pressure, conveyed to the second chamber volume  134  through the gate valve  102 , and processed in the second chamber volume  134  at a second chamber pressure. In some embodiments, the first chamber pressure and the second chamber pressure are the same. In other embodiments, the first chamber pressure and the second chamber pressure are different. 
     The gate valve  102  is configured to provide selective isolation between the first chamber volume  114  and the second chamber volume  134 . For example, isolation between the first chamber volume and the second chamber volume may be desired when one of the chamber volumes needs to be at atmospheric pressure and temperature in order to repair the affected chamber, perform substrate loading adjustments in one of the chambers, or due to an emergency stop. The gate valve  102  includes a plurality of sealing members (four sealing members  104  shown in  FIG. 1 ). In some embodiments, the sealing members may be compliant bladders that can inflate to form a seal, and deflate to open. The sealing members  104  can close while the continuous substrate  154  is disposed through the gate valve without damaging the continuous substrate  154 . In some embodiments, a purge gas, such as an inert gas, for example nitrogen (N 2 ) gas, can be provided to a volume  108  between two of the sealing members  104 . In some embodiments, a vacuum, for example from a vacuum source  116 , may be provided to one or more volumes between two of the sealing members  104 . In some embodiments, the vacuum source  116  is coupled to volumes  112  and  114  disposed on either side of the volume  108  to provide a vacuum in respective volumes on either side of the purge gas provided to the volume  108 . 
       FIGS. 2A and 2B  depict a gate valve  200  suitable for use as the gate valve  102  in further detail, and illustrate the gate valve  200  in both open ( FIG. 2A ) and closed ( FIG. 2B ) positions. For ease of illustration only, certain elements, such as the purge gas source, valves, and conduits shown in  FIG. 2A  are omitted from the view in  FIG. 2B  so as not to clutter the figure. 
       FIG. 2A  depicts a schematic side view of the gate valve  200  in accordance with some embodiments of the present disclosure. The gate valve  200  includes a body  202  having an opening  206  disposed through the body  202  (for example, from a first surface  208  of the body  202  to an opposing second surface  210  of the body  202 ). The gate valve  200  is coupled to the first chamber  110  (on one side of the opening  206 ) and to the second chamber  130  (on the other side of the opening  206 ). The body may also include a first side  218 , and a second side  220  opposite the first side  218  which together with the first surface  208  and second surface  210  form a shape of the body. The body  202  may have any suitable shape as required for a particular application, for example, the body  202  may have a suitable shape appropriate for coupling the gate valve  200  to the first and second chambers  110 ,  130  or to another chamber, as appropriate. The body  202  may be fabricated from one or more process-compatible materials, including non-limiting examples such as stainless steel or aluminum. 
     The gate valve  200  may further include a plurality of seals  212  disposed between the first surface  208  and the second surface  210  of the body  202  proximate the opening  206 . In some embodiments, for example, as depicted in  FIGS. 2A and 2B , the plurality of seals are disposed parallel to the first surface  208  and the second surface  210  of the body  202 . The plurality of seals  212 , for example, may be part of the body  202 , or may be welded, bolted, or otherwise affixed to the body  202 . The plurality of seals  212  may be fabricated from an elastic or stretchable material, such as rubber bladders. The plurality of seals  212  are disposed within the body, and configured to move between a closed position and an open position. A plurality of volumes  238  is defined by the plurality of seals  212  and the body  202 . Each respective volume  238  is disposed between adjacent seals  212 . For example, as depicted in  FIGS. 2A-B , there are four seals  212 , and accordingly three volumes  238 . 
     The gate valve may further include a gas inlet  232  having a valve disposed through the first side  218  of the body and fluidly coupled to an innermost one of the plurality of volumes  238  (e.g., a central one of the volumes  238 ). The gate valve may also include a gas outlet  234  disposed through the second side  220  of the body and fluidly coupled to other ones of the plurality of volumes  238  disposed on opposite sides of the central volume  238 . A purge gas source  242  (shown in  FIG. 2B ) is coupled to the gas inlet  232  to deliver a purge gas to the innermost one of the plurality of volumes  238 . The purge gas may be nitrogen (N 2 ), although other appropriate process-inert gas, including, as non-limiting examples, helium (He), argon (Ar), or the like, or mixtures of inert gases, may be used as the purge gas. A vacuum pump  244 , for example, a turbo pump or the like, is fluidly coupled to the gas outlet  234 . 
     In operation, a continuous substrate  154  may be processed in the first and second chamber volumes  114 ,  134 , as discussed above. As depicted in  FIG. 2A , in the open position of the gate valve  200 , the gas inlet  232  coupled to the purge gas source  242 , and the gas outlet  234  coupled to the vacuum pump  244  are closed, and the first chamber pressure is the same as the second chamber pressure, as the continuous substrate is processed. In the event that the first chamber pressure is required to be different from the second chamber pressure, for example for substrate loading adjustments or repairs, the gate valve  200  is moved to the closed position facilitating establishment of a pressure difference between the first chamber and the second chamber. The purge gas source  242  and vacuum pump  244  are not shown in  FIG. 2A  for clarity. 
     As depicted in  FIG. 2B , in the closed position, the plurality of seals  212  partially seal the opening  206  and create a corresponding plurality of small leaks  216  along the opening  206 . As depicted in  FIG. 2B , in the closed position of the gate valve  200 , the gas inlet  232  coupled to the purge gas source  242 , and the gas outlet  234  coupled to the vacuum pump  244  may be opened, such that the innermost one of the plurality of volumes  238  stays at a pressure P 1  different from the other ones of the plurality of volumes  238  (e.g., P 2  and P 3 ). For example, the innermost one of the plurality of volumes  238  may be maintained at a pressure a higher than the other ones of the plurality of volumes  238  due to the flow of the purge gas from purge gas source  242 . Any purge gas escaping through the leaks  216  may be carried away via the vacuum pump  244 . As such, if for example, one chamber is undergoing repairs, performed at atmospheric pressure, the non-affected chamber may remain at a processing pressure, different from the pressure at atmospheric conditions, such as lower than atmospheric pressure. Thus, the pressure difference is maintained or substantially maintained, and the repair of one of the chambers is completed without bringing the whole system to atmospheric pressure. Also, the disclosed gate valve produces the desired pressure gradient without compromising the physical integrity of a continuous substrate at the sealing interface, when present. 
       FIG. 3A-3B  respectively depict a schematic side view of a gate valve in an open and a closed position in accordance with at least some embodiments of the present disclosure. As depicted in  FIG. 3A-3B , in some embodiments, the plurality of seals may be provided by a plurality of angled walls  312  having respective openings  306  that can be selectively sealed via movable sealing members  305 . For example, the sealing members  305  may operate similar to slit valves disposed below each one of the plurality of angled walls  312 , and configured to move between a first position (e.g., an open position as depicted in  FIG. 3A ) and a second position (e.g., a closed position as depicted in  FIG. 3B ). 
     Each sealing member  305  may be independently controlled to provide individualized flow conditions (e.g., individualized control of mass flow, volume flow, pressure, etc.) to each one of the other ones of the plurality of volumes  238 . Accordingly, in some embodiments, mass flow controllers, volume flow controllers, or pressure regulators may be coupled to the volumes disposed between the angled walls  312 . 
     In some embodiments, sealing members  305  are pneumatically controlled between at least the first position in which the valve is fully open and the second position in which the valve is fully closed. In some embodiments, the sealing members  305  may be controlled by other mechanisms, for example servo motors. In the exemplary open position depicted on  FIG. 3A , the sealing members  305  are in the first position and the gate valve is fully open to maintain a common pressure between the first chamber  110  and the second chamber  130  (as depicted in  FIG. 1 ). The purge gas source  242  and vacuum pump  244  are shown only in  FIG. 3B  for clarity. 
     In the exemplary closed position, depicted in  FIG. 3B , the sealing members  305  partially seal the opening  206  and create a corresponding plurality of leaks  216  along the opening  206 . The plurality of seals  212  and sealing members  305  are advantageously tilted to enhance gas flow and maintain a desired pressure gradient. The amount of tilt depends on the vertical offset between the gas inlet  232  and the gas outlet  234 . As depicted in  FIGS. 3A and 3B , the gas outlet  234  is disposed at a height below the gas inlet  232 . 
     In the exemplary closed position depicted in  FIG. 3B , the plurality of sealing members  305  move from the first position to the second position in a direction counter to the tilt angle to engage the plurality of seals  212  and seal the opening  206 . Similar to the illustrative embodiment in  FIG. 2B , a corresponding plurality of leaks  216  along the opening  206  is created. Similar to the illustrative embodiment in  FIG. 2B , the gas inlet  232  coupled to the purge gas source  242  and the gas outlet  234  coupled to the vacuum pump  244  are open, such that the innermost one of the plurality of volumes  238  can be maintained at a pressure different from the other ones of the plurality of volumes  238 . For example, the innermost one of the plurality of volumes  238  may be maintained at a pressure a higher than the other ones of the plurality of volumes  238  due to the flow of the purge gas from purge gas source  242 . Similarly, the inventive gate valve including sealing members  305  advantageously produces a pressure gradient without compromising the physical integrity of a continuous substrate at the sealing interface. 
     In operation, a method of processing a continuous substrate using the above disclosed apparatus includes processing a continuous substrate in at least one of a first process chamber or a second process chamber coupled to the first process chamber through a gate valve. The continuous substrate is simultaneously disposed through each of the first process chamber, the gate valve, and the second process chamber. The gate valve can be closed while the continuous substrate is disposed therethrough to substantially isolate the first process chamber from the second process chamber. In some embodiments, the first process chamber is maintained at a vacuum pressure and a pressure of the second process chamber can be increased while substantially maintaining the pressure in the first process chamber. In some embodiments, the pressure of the second process chamber can be increased to substantially atmospheric pressure while substantially maintaining the pressure in the first process chamber. In some embodiments, service can be performed on the second process chamber while substantially maintaining the pressure in the first process chamber. 
     Thus, embodiments of improved gate valves and methods of using the same have been provided herein. The inventive gate valves and methods of using may advantageously ensure that a non-affected chamber of a system of chambers may remain at a processing pressure, different from, for example the atmospheric conditions required for the affected chambers. 
     While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof.