Patent Publication Number: US-11049735-B2

Title: Methods and apparatus for conserving electronic device manufacturing resources

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a division of U.S. patent application Ser. No. 14/610,301, filed Jan. 30, 2015, titled “APPARATUS FOR CONSERVING ELECTRONIC DEVICE MANUFACTURING RESOURCES INCLUDING OZONE,” now U.S. Pat. No. 9,685,352, which is a division of U.S. patent application Ser. No. 12/410,435, filed Mar. 24, 2009, titled “METHODS AND APPARATUS FOR CONSERVING ELECTRONIC DEVICE MANUFACTURING RESOURCES,” now U.S. Pat. No. 8,974,605, which claims the benefit of U.S. Provisional Patent Application No. 61/039,415, filed Mar. 25, 2008, and titled “APPARATUS AND METHODS FOR REDUCING ENERGY USE IN ELECTRONIC DEVICE MANUFACTURING.” All of the above applications are hereby incorporated by reference herein in their entireties. 
    
    
     FIELD 
     The present invention relates generally to electronic device manufacturing and is more particularly directed to reducing the amount of resources which are used in electronic device manufacturing processes. 
     BACKGROUND 
     Some electronic device manufacturing processes may use large quantities of reagents and/or other materials, and some of these reagents may be harmful and/or hazardous if released to the atmosphere. It is known to abate harmful or otherwise hazardous regions and reagent byproducts through the use of abatement systems which convert the reagents or their byproducts into less harmful and/or less hazardous compounds. While the abatement of these reagents and their byproducts may address the issue of the harmful and/or hazardous nature of the reagents/byproducts, it does not address the fact that a significant quantity of expensive reagents may eventually be wasted when the reagents pass unused through a process chamber. 
     Other materials, which although they may not be harmful or hazardous, still represent a large cost for electronic device manufacturing systems. 
     It is desirable therefore to develop methods and apparatus which would reduce the amount of reagents and/or other materials which are required to be produced and/or purchased for use in electronic device manufacturing processes. 
     SUMMARY 
     In one aspect, a method for operating an electronic device manufacturing system is provided, including the steps: introducing an inert gas into a process tool vacuum pump at a first flow rate while the process tool is operating in a process mode; and introducing the inert gas into the process tool vacuum pump at a second flow rate while the process tool is operating in a clean mode. 
     In another aspect, a method of operating an electronic device manufacturing system is provided, including the steps: introducing an inert gas into an inlet of an abatement tool at a first flow rate when a process tool for which the abatement tool abates effluent is operating in a process mode; and introducing the inert gas into the inlet of the abatement tool at a second flow rate when the process tool is operating in a clean mode. 
     In another aspect, a method of operating an electronic device manufacturing system is provided, including the steps: directing effluent ozone from an electronic device manufacturing tool into an abatement tool for use as an oxidant. 
     In another aspect, an electronic device manufacturing system is provided, including: a process tool; an ozone supply adapted to supply ozone to the process tool; an abatement unit adapted to receive effluent from the process tool; and a conduit connecting the abatement unit to the process tool which conduit is adapted to direct ozone which exits the process tool into the abatement unit as an oxidant. 
     Other features and aspects of the present invention will become more fully apparent from the following detailed description, the appended claims and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic depiction of a system for reducing the use of inert gas to facilitate pumping of effluent and to protect a vacuum pump. 
         FIG. 2  is a schematic depiction of a system for reducing the use of inert gas to form an annular sheath of inert gas around an effluent gas within an abatement unit. 
         FIG. 3  is a schematic depiction of a system for using process tool effluent ozone as an oxidant in an abatement unit. 
         FIG. 4  is a schematic depiction of an alternate embodiment of the system of  FIG. 3 . 
         FIG. 5  is a schematic depiction of a second alternate embodiment of the system of  FIG. 3 . 
         FIG. 6  is a schematic depiction of a third alternate embodiment of the system of  FIG. 3 . 
         FIG. 7  is a schematic depiction of a fourth alternate embodiment of the system of  FIG. 3 . 
         FIG. 8  is a schematic depiction of a fifth alternate embodiment of the system of  FIG. 3 . 
         FIG. 9  is a flowchart of a method of the present invention for reducing the use of inert gases in an electronic device manufacturing system. 
         FIG. 10  is a flowchart of a method of the present invention for reducing the use of inert gases in an electronic device manufacturing system. 
         FIG. 11  is a flowchart of a method of the present invention for reducing the need for abatement and the need for oxidant for abating electronic device manufacturing system effluent. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic device manufacturing processes may use large amounts of inert gases, such as nitrogen. Nitrogen, although perhaps not as expensive as some reagents used in electronic device manufacturing, is typically used in volumes large enough to represent a significant cost for an electronic device manufacturing facility. 
     For example, prior to the present invention, nitrogen has typically been supplied to vacuum pumps for the purpose of facilitating the pumping of hydrogen which, due to its size, may be difficult to pump. Supplying nitrogen to the vacuum pumps may increase the viscosity of the gas to be pumped, thereby reducing the pump effort required to pump the gas and thereby reducing the amount of heat which may be imparted to the gas being pumped. In addition, the nitrogen, which may have been boiled off from a container of liquid nitrogen, may typically be at ambient temperature or lower and thus may serve to cool the vacuum pumps. Another reason for flowing nitrogen into the vacuum pumps may be that the nitrogen dilutes cleaning chemistry which may be passing through the pumps and therefore may reduce the detrimental effect of cleaning chemistry on the pump parts and lubricants. 
     Methods of the present invention reduce the amount of nitrogen which is required to operate electronic device manufacturing facility by tuning the amount of nitrogen supplied to vacuum pumps depending upon whether a process is being performed in a process tool, and if so, the nature of the process, such as, for example, substrate processing or chamber cleaning. 
     Nitrogen may also be used to protect reaction chamber walls in abatement tools from becoming coated with particulate matter. Thus, nitrogen may be introduced into an abatement tool inlet through which effluent to be abated enters the abatement tool. The inlet may be designed to inject the nitrogen into the abatement tool in the form of an annular sheath around the effluent to be abated. This may have the beneficial effect of preventing oxidation of the effluent until the effluent has traveled further into the abatement tool and may form a protective zone of inert gas proximate to the walls of the reaction chamber through which particulate matter may have difficulty penetrating. 
     Methods of the present invention reduce the amount of nitrogen which is required to operate the abatement tool by tuning the amount of nitrogen supplied to the abatement tool depending upon whether a process is being performed in the process tool, and if so, the nature of the process. For example, when a cleaning cycle is being performed, we have found that it is beneficial to stop supplying nitrogen to the abatement tool inlet, and that a beneficial cleaning effect may occur in the abatement tool. 
     In another example prior to the present invention, ozone, which may be used as a reagent in some electronic device manufacturing processes, such as, for example, atmospheric chemical vapor deposition, and the production of organic light emitting diodes, may typically be separately abated. This may require the cost of purchasing and operating additional abatement equipment. 
     By using additional methods and apparatus of the present invention, the need for abating ozone may be obviated by using the ozone which exits a process chamber as an oxidant in an abatement tool. This has the added benefit of reducing the amount of oxidant which may need to be purchased or otherwise supplied to the abatement tool. 
       FIG. 1  is a schematic drawing of a system  100  of the present invention for reducing the use of inert gas. System  100  may include any electronic device manufacturing process tool  102 . Process tool  102  may be a CVD chamber, a PVD chamber, an epitaxial chamber, or any other electronic device manufacturing process tool which produces an effluent byproduct which requires abatement. Process tool  102  may be connected by a conduit  104  to a blower  105 , a mechanical pump  108 , and an abatement tool  110 . The system  100  may also include a nitrogen supply  112  which may be adapted to introduce nitrogen into an effluent stream flowing through conduit  104  at mixing junction  114 . Mixing junction  114  may be a T-junction or any other suitable junction. As described above, the introduction of nitrogen into the effluent stream flowing through conduit  104  facilitates the pumping of smaller molecules such as hydrogen by the mechanical pump  108 . The nitrogen, which may be at ambient temperature or below, may also serve to help reduce the temperature of the pump  108  and the effluent flowing through the pump  108 . The system  100  may also include controller  116  which may be connected to the process tool  102 , through signal line  118  and to the nitrogen supply  112  through signal line  120 . Controller  116  may be a computer or any logic device such as a PLC, etc. 
     In operation, process tool  102  may typically be in one of several operating modes. For example, process tool  102  may be in a process mode, where it may be performing a manufacturing step on an electronic device or substrate, or in a clean mode where process chambers (not shown) of the process tool  102  may be cleaned. In both of these modes, the process tool  102  may produce effluent which requires abatement. The process tool  102  may also be in an off mode, such as, for example, when maintenance needs to be performed on the process tool. 
     When the process tool  102  is in a process mode or in a clean mode, effluent may typically flow out of the process tool  102  through conduit  104 . The blower  105 , which may be a roots type blower, for example, may create a vacuum which moves effluent from the process tool  102  through conduit  104  to pump  108 . The pump  108  may be a mechanical pump or a set of staged mechanical pumps. The pump  108  may cause the effluent contained in conduit  104  to move into the abatement tool  110  where the effluent may be abated. 
     As discussed above, nitrogen may be introduced into the effluent stream in conduit  104  from nitrogen supply  112  through mixing junction  114 . According to the present invention, the amount of nitrogen which may be supplied from the nitrogen supply  112  into the conduit  104 , may then beneficially be selected based upon the operating mode of the process tool  102 . Thus, for example, when the process tool is in a process mode, it may be producing effluent at a known rate. This rate may be known based upon experience, or may be calculated. Similarly the viscosity of the effluent may be measured by any suitable means, or may also be calculated. Once the viscosity of the effluent is known, an appropriate amount of nitrogen may be injected into the effluent stream through mixing junction  114 . 
     When the process tool  102  is in the clean mode, nitrogen may also be injected into the effluent stream in conduit  104 . In the clean mode, not only may nitrogen increase the viscosity of the effluent flowing from the process tool  102 , but there may be an additional reason for injecting an inert gas such as nitrogen into the effluent stream. When the process tool is in clean mode the effluent may be highly reactive, and if not diluted, may have a detrimental effect on components and/or lubricants of the pump  108 . The amount and concentration of clean mode effluent which flows through conduit  104  during a clean mode of process tool  102 , may also be known or calculated. Once the amount and concentration of clean mode effluent is known, then an appropriate amount of inert gas such as nitrogen may be injected into mixing junction  114  to dilute the clean mode effluent. 
     The first amount of inert gas which may be required during a process mode and the second amount of inert gas which may be required during a clean mode, may be the same or different. However, rather than choosing the greater of the first amount and a second amount of inert gas and supplying that amount steadily, the system  100  of the present invention may provide enough but not more inert gas than is needed in any particular mode. 
     In addition to process mode and clean mode, the process tool  102  may also be in an off mode. When the process tool  102  is in an off mode, the pump  108  may not need nitrogen to assist it with pumping or to dilute clean mode effluent. It may be beneficial, however, to flow a sufficient amount of nitrogen into the conduit  104  during times when the process tool  102  is in an off mode, to prevent ambient air from entering the conduit  104 , due to potentially hazardous conditions which may occur when ambient air contacts any dust which may be in the conduit  104 . 
     The controller  116  may be in communication with the process tool through signal line  118  and may at all times know what mode the process tool is in. The controller  116 , knowing what mode the process tool is in, may then command the nitrogen supply to inject an appropriate amount of nitrogen into conduit  104  through mixing junction  114 . Although not shown, the controller  116  may use one or more valves to modulate the amount of nitrogen which flows from the nitrogen supply  112  into the effluent stream. 
       FIG. 2  is a schematic drawing of a system  200  of the present invention for reducing the use of inert gas. The system  200  may include a process tool  102 , similar to the process tool  102  of system  100 . The process tool  102  may be connected through a conduit  104  to an inlet  106  of an abatement tool  110 , through which effluent from the process tool  102  may enter the abatement tool  110 . The system  200  may also include nitrogen gas supply  112  which may be connected to inlet  106  through conduit  115 . A controller  116  may be connected to the process tool  102  through signal line  118  and to nitrogen supply  112  through signal line  120 . 
     In operation, the system  200  may operate in a similar manner to the system  100  of  FIG. 1 . Thus, the process tool  102  may be in a process mode, a clean mode, or an off mode. When the process tool  102  is in the process mode, it may produce as a byproduct effluent which needs to be abated. The effluent may flow through conduit  104  into inlet  106 . As discussed above, nitrogen may be introduced from nitrogen supply  112  through conduit  115  into inlet  106 . The inlet  106  may be adapted to introduce the nitrogen into the abatement tool in the form of an annular sheath of nitrogen gas. When effluent is flowing from the process tool into the inlet  106 , the inlet  106  may introduce the effluent into the abatement tool  110  in the form of an effluent gas stream which is surrounded by the annular sheath of nitrogen gas. 
     Prior to the present invention, the nitrogen supplied to the inlet  106  may be supplied continuously, without taking into account the mode of the process tool  102 . We have discovered that, when the process tool  102  is in the clean mode, it may be beneficial to the abatement tool  110  to stop the flow of nitrogen. Stopping the flow of nitrogen during the clean mode may result in fewer particulate deposits on interior chamber walls of the abatement tool  110 . Similarly, when the process tool  102  is in an off mode, the flow of nitrogen into the inlet  106  may be stopped. 
     The controller  116 , which may be connected to the process tool  102  through signal line  118 , may be aware of the mode of the process tool  102  at all times. The controller, knowing the operating mode of the process tool  102 , may then command the nitrogen supply  112  to either supply nitrogen to the inlet  106  when the process tool  102  is in the process mode, or to stop the flow of nitrogen to the inlet  106  when the process tool  102  is in the clean mode or the off mode. 
       FIG. 3  is a schematic drawing of a system  300  of the present invention for reducing the use of resources. The system  300  may include a process tool  302  which uses ozone and a process. The ozone may be supplied to the process tool  302  from an ozone supply  304  connected to the process tool  302  through conduit  306 . The process tool  302  may also be connected through conduit  308  to abatement tool  310 , such that effluent may pass from the process tool  302  into the abatement tool  310  to be abated. Oxidant supply  312  may be connected, and supply oxidant, to the abatement tool  310  through conduit  314 . The oxidant supply  312  may also be connected to the conduit  308  through conduit  316  and valve  318 . 
     Controller  320  may be connected to the process tool  302  through signal line  322 , and to the valve  318  through signal line  324 . 
     In operation, the process tool  302  of the system  300  may operate in multiple operating modes. For example, the process tool  302  may operate in an ozone mode and in a non-ozone mode. The ozone mode may be any operation where ozone is introduced into the process tool  302  from the ozone supply  304  and in which unreacted ozone exits the process tool  302  as effluent. The non-ozone mode may be any other mode in which ozone is not being supplied to the process tool  302 , and is not exiting the process tool  302  as effluent. 
     When the process tool  302  is operating in an ozone mode, the controller may configure valve  318  to divert the ozone which may be exiting the process tool  302  through conduit  308  into conduit  316  and then into oxidant supply  312 . When ozone is diverted into the oxidant supply  312 , it does not need to be abated, and may reduce the requirement for externally supplied oxidant. Conversely, when the process tool  302  is in a non-ozone mode, the controller  320  may configure valve  318  to direct any effluent from the process tool  302  into the abatement tool  310 . 
       FIG. 4  is a schematic drawing of a system  400  of the present invention for reducing the use of resources. System  400  may be similar to the system  300  of  FIG. 3  with the following differences. The oxidant supply  312  of system  400  is not connected to the conduit  308  through the conduit  316  and the valve  318  as it is in the system  300  of  FIG. 3 . Instead, the oxidant supply  312  may be connected directly to the process tool  302  through a conduit  326  and valve  328 . In addition, the system  400  may include a valve  330  which may be located between conduit  308  and process tool  302 , and connected to controller  320  through signal line  332 . 
     In operation, the system  400  may operate in a manner similar to the system  300 , with the following differences. In the system  400 , when the process tool  302  is in the ozone mode, the controller  320  may command the valve  330  to close and the valve  328  to open, thereby diverting ozone from the process tool  302  into the oxidant supply  312 . In the non-ozone mode. The controller  320  may close valve  328  and open valve  330  to divert effluent requiring abatement into the abatement tool  310 . 
       FIG. 5  is a schematic drawing of a system  500  of the present invention for reducing the use of resources. System  500  may be similar to the system  300  of  FIG. 3  with the following differences. In system  500 , the oxidant supply  312  may not be adapted to receive ozone at all. Instead, the conduit  308  may be connected to the conduit  314  through valves  318 ,  334  and conduit  316 . 
     In operation, the system  500  may operate in a manner similar to that of the system  300  of  FIG. 3 , with the following differences. In system  500 , when the process tool  302  is in an ozone mode the controller  320  may command the valve  318  to divert ozone through the conduit  316  into the conduit  314  through valve  334 , which may prevent back flow of oxidant from conduit  314  into conduit  316 . When the process tool is in a non-ozone mode the system  500  may direct effluent requiring abatement from the process tool  302  through conduit  308  and valve  318  into the abatement tool  310 . 
       FIG. 6  is a schematic drawing of a system  600  of the present invention for reducing the use of resources. The system  600  may be similar to the system  500  with the following differences. In the system  600 , the conduit  316  connects the conduit  314  with the process tool  302  rather than connecting the conduit  314  to conduit  308  as it does in system  500 . 
     In operation, the system  600  may operate in a manner similar to the system  500 . 
       FIG. 7  is a schematic drawing of a system  700  of the present invention for reducing the use of resources. The system  700  may be similar to the system  400  with the following differences. In the system  700 , the conduit  316  connects the process tool through valve  328  to the abatement tool, instead of to the oxidant supply  312 . 
     In operation, the system  700  may operate in a manner similar to the system  400 . 
       FIG. 8  is a schematic drawing of a system  800  of the present invention for reducing the use of resources. The system  800  may be similar to the system  300  with the following exceptions. In the system  800 , the conduit  316  connects the conduit  308  through valve  318  to the abatement tool  310  directly and not to the oxidant supply  312  as it does in the system  300 . 
     In operation, the system  800  may operate in a manner similar to the system  300 , with the following exceptions. When the process tool  302  is in an ozone mode, the controller may configure valve  318  to divert ozone through the conduit  316  into the abatement tool  310 . When the process tool is in a non-ozone mode, the controller  320  may configure the valve  318  to direct effluent requiring abatement from the process tool  302  into the abatement tool  310 . 
       FIG. 9  is a flowchart of a method  900  of the present invention for reducing the use of inert gases in an electronic device manufacturing system. In step  902 , inert gas, typically nitrogen, is introduced at a first flow rate into a vacuum pump which is being used to evacuate effluent from a process tool which is in the process mode. As described above, the first flow rate of inert gas may be a rate sufficient to raise the viscosity of the effluent to a predetermined viscosity. In step  904 , the inert gas is introduced into the vacuum pump at a second flow rate when the process tool is operating in a clean mode. As discussed above, the second flow rate of inert gas may be a rate sufficient to dilute the clean effluent to reduce the possibility of damaging the vacuum pump and/or the vacuum pump&#39;s lubrication. Finally, in step  906 , inert gas is introduced into the vacuum pump at a third flow rate when the process tool and/or the vacuum pump are in an off mode. As discussed above, the third flow rate may be a flow rate which is sufficient to prevent ambient air from entering the abatement system. 
       FIG. 10  is a flowchart of another method  1000  of the present invention for reducing the use of inert gases in an electronic device manufacturing system. In step  1002  inert gas is introduced into an abatement tool in let at a first flow rate when the process tool is operating in a process mode. The first flow rate may be a flow rate sufficient to prevent some particulate matter from adhering to an interior wall of the abatement unit. As described above, the inert gas may enter the abatement unit in the shape of annular sheath through which particulate matter may have difficulty passing to reach the interior wall of the abatement unit. In step  1004  gas is introduced into an abatement tool inlet of the second flow rate when the process tool is operating in a clean mode. As described above, the second flow rate may be a zero flow rate. It has been observed that when the second flow rate is a zero flow rate, the abatement tool may experience fewer particulates adhering to the inside wall of the abatement tool. In step  1006 , the inert gas is introduced into the abatement tool inlet and a third flow rate when the process tool is in an off mode. The third flow rate may be a zero flow rate. 
       FIG. 11  is a flowchart of a method  1100  of operating an electric device manufacturing system using process tool effluent ozone as an oxidant in an abatement tool. In step  1102 , process tool effluent ozone is directed into an abatement tool for use as an oxidant when the process tool is operating in an ozone mode. In step  1104 , process tool effluent is directed into the abatement unit to be abated when the process tool is operating in a non-ozone mode. 
     The foregoing description discloses only exemplary embodiments of the invention. Modifications of the above disclosed apparatus and methods which fall within the scope of the invention will be readily apparent to those of ordinary skill in the art. In some embodiments, the apparatus and methods of the present invention may be applied to semiconductor device processing and/or electronic device manufacturing. 
     Accordingly, while the present invention has been disclosed in connection with exemplary embodiments thereof, it should be understood that other embodiments may fall within the scope of the invention, as defined by the following claims.