Abstract:
Embodiments disclosed herein include a controller for a treatment system for lessening the hazard of effluents produced in a processing system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of U.S. Provisional Application Ser. No. 62/049,658, filed Sep. 12, 2014 (Attorney Docket No. APPM/21786USL), of which is incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    Embodiments of the present disclosure generally relate to semiconductor processing equipment. More particularly, embodiments of the present disclosure relate to a controller for the treatment of compounds produced in semiconductor processes. 
         [0004]    2. Description of the Related Art 
         [0005]    The process gases used in semiconductor processing include many compounds which can be hazardous. The effluent from these processing facilities may contain thee hazardous compounds or other harmful byproducts which must be treated before disposal due to regulatory requirements and/or environmental and safety concerns. Among these compounds are perfluorocarbons (PFCs), which are used, for example, in etching processes. Therefore, modern processing equipment include treatment technology for the hazardous effluent generated therein. 
         [0006]    An inductively coupled plasma (ICP) source, along with other reagents, has been used for the treatment of PFCs and other global warming gases. The plasma generated by the ICP plasma source dissociates these compounds, and the dissociated gases react to form less hazardous materials. However, in order to effectively treat the hazardous compounds to lesser hazardous constituents, the pre-treatment and abatement technology and methodology has become more complex. Current abatement technology have difficulty treating certain types of gases and particulate matter used and generated in deposition processes, such as insulating or conducting materials generated therefrom. As the treatment of the hazardous compounds become more complex, control over the treatment process has increased in complexity as well. 
         [0007]    Controls for current treatment technology rely on commercially available programmable logic controllers (PLCs). However, PLCs have limited functionality and often can only control the treatment process along a very narrow and exact routine. At least some hardware adaptations and external logic is required and programming is typically limited to very simple logical structures, if “programmable” at all. Moreover, programming the PLCs to provide error reporting, system interface ports and data logging is essentially unknown in general industry and may in fact be infeasible (such as in relay logic implementations) due to the nature of current PLC designs. 
         [0008]    Accordingly, there is needed in the art for an improved controller for operating treatment technology in the semiconductor processes. 
       SUMMARY 
       [0009]    Embodiments disclosed herein include controller for treatment of semiconductor processing equipment effluent, along with a method for treating hazardous effluents produced by a semiconductor processing system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0011]      FIG. 1  is a schematic side view of a semiconductor processing system having an effluent pre-treatment system managed by a controller. 
           [0012]      FIG. 2  is a schematic top view of the effluent pre-treatment system. 
           [0013]      FIG. 3  is a block diagram of the controller of the effluent pre-treatment system. 
           [0014]      FIG. 4  is a flow diagram of a method for treating hazardous effluents produced by a semiconductor processing system. 
       
    
    
       [0015]    To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. 
       DETAILED DESCRIPTION 
       [0016]      FIG. 1A  is a schematic side view of a semiconductor processing system  170  having an effluent pre-treatment system  120  managed by a controller  100 . The semiconductor processing system  170  includes a vacuum processing chamber  190 . The vacuum processing chamber  190  is generally configured to perform at least one integrated circuit manufacturing process, such as a physical vapor deposition process, chemical vapor deposition process, a plasma-assisted (dry) etch process, a plasma treatment process, a substrate anneal process, a preclean process, an ion implant process, or other integrated circuit manufacturing process. The process performed in the vacuum processing chamber  190  may be plasma assisted. In one example, the process performed in the vacuum processing chamber  190  may be plasma deposition process for depositing a silicon-based material. In another example, the process performed in the vacuum processing chamber  190  may be a plasma-assisted etch process for forming features, such as trenches or vias, in a silicon based material. 
         [0017]    The vacuum processing chamber  190  has a chamber exhaust coupled by a foreline  192  to the effluent pre-treatment system  120 . The exhaust of the effluent pre-treatment system  120  is coupled by an exhaust conduit  194  to pumps and facility exhaust, schematically indicated by a single reference numeral  196  in  FIG. 1 . The pumps are generally utilized to evacuate the vacuum processing chamber  190 , while the facility exhaust generally includes scrubbers or other exhaust cleaning apparatus for preparing the effluent of the vacuum processing chamber  190  to enter the atmosphere. A flow of the effluent is shown schematically by arrow  110 . 
         [0018]    The effluent pre-treatment system  120  is utilized to perform a pre-treatment or an abatement process on gases, compounds and/or other materials exiting the vacuum processing chamber  190  so that such gases and/or other materials may be converted into a more environmentally and/or process equipment friendly composition. Details of the effluent pre-treatment system  120  and the control thereof, are further described below in  FIG. 2 . 
         [0019]    In some implementations, a treatment reagent source  114  is coupled to at least one of the foreline  192  and/or the effluent pre-treatment system  120 . The treatment reagent source  114  provides a reagent into the effluent pre-treatment system  120  which may be energized to react with, or otherwise assist converting, the materials exiting the vacuum processing chamber  190  into a more environmentally and/or process equipment friendly composition. 
         [0020]    Optionally, a pressure regulating module  182  may be coupled to at least one of the effluent pre-treatment system  120  and/or the exhaust conduit  194 . The pressure regulating module  182  injects a pressure regulating gas, such as Ar, N, or other suitable gas, which allows the pressure within the effluent pre-treatment system  120  to be better controlled, and thereby provide more efficient abatement performance. For example, pressure regulating gas provided by the pressure regulating module  182  may be utilized to stabilize the flow rates and/or pressure of the effluent passing through the effluent pre-treatment system  120 , thereby allowing more predictable process control for better control of the abatement results. 
         [0021]    The effluent pre-treatment system  120  is disposed downstream of the vacuum processing chamber  190 . The plasma generated in the effluent pre-treatment system  120  energizes and/or dissociates, partially or fully, the compounds within the effluent coming out of the vacuum processing chamber  190 , converting the compounds in the effluent into more benign form. 
         [0022]      FIG. 2  is a schematic top view of the effluent pre-treatment system  120 . The effluent pre-treatment system  120  is managed by the controller  100  and includes a plasma reactor  210 . The effluent pre-treatment system  120  has a containment  211  with a door  204  which surrounds the plasma reactor  210 . The containment  211  generally protects technicians from potential heat and electrical power hazards that may be generated by the effluent pre-treatment system  120 . A sensor  206  may be disposed adjacent to the door  204 . The sensor  206  is operable to provide a metric, such as a signal, indicative of the position of door  204 . For example, the sensor  206  may be operable to provide a metric indicative of if the door  204  is in a closed and/or secured position. 
         [0023]    The plasma reactor  210  has a body  202  and a first opening  220  from which the effluent may enter and second opening  222  from which the effluent may exit. The first opening  220  may be configured to couple to the foreline  192  and the second opening  222  may be configured to couple to the exhaust conduit  194 . The body  102  may be circular, square, rectangular, or in other suitable shape. In one embodiment, the body  102  has a torroidal shape. A center portion  203  may be formed through the body  102 . The center portion  203  may be circular, square, rectangular, or in other suitable shape. In one embodiment, the body  102  and center portion form a torus shape in an interior volume  224 . In other embodiments, the body  102  does not include the center portion  203 . 
         [0024]    The body  202  may have a temperature sensor  208 . The temperature sensor  208  may provide temperature information about the plasma reactor  210 . For example, the plasma reactor  210  may be at a temperature wherein the treatment of the effluent may not be adequate or the temperature may damage process equipment. The thermal sensor may provide discrete temperature readings or signal a maximum or minimum threshold. 
         [0025]    The plasma reactor  210  has an RF antenna  236 . The RF antenna  236 , such as one or more inductor coils, may be provided adjacent to the body  202  of the plasma reactor  210 . An RF generator  230  may power the RF antenna  236  through a match circuit  232  to inductively couple energy, such as RF energy, to the effluent gas to maintain a plasma formed from the effluent gas in the plasma reactor  210  of the effluent pre-treatment system  120 . An RF sensor  235  may monitor or measure the RF from the RF antenna  236 . The RF sensor may provide feedback to the controller  100 . Additionally a generator sensor  234  may be coupled to the RF generator  230 . The generator sensor  234  may include or be a relay for controlling the flow of energy from the RF generator  230  to the RF antenna  236 . The generator sensor  234  may also interface with the RF generator  230  and monitor information indicative of the state of the generator. The operation of the RF generator  230  may be controlled independently and/or through the generator sensor  234  by the controller  100 , that also controls the operation of other components in the effluent pre-treatment system  120 . 
         [0026]    The effluent, such as the by-products exiting the vacuum processing chamber  190  or in the example where the effluent pre-treatment system  120  is a remote plasma source, as precursor and/or carrier gases for generating a remote plasma, may have a flow shown by arrow  110  and enter the plasma reactor  210  through the first opening  220 . The by-products in the effluent may include silicon, tungsten, titanium, or aluminum containing materials. Examples of silicon-containing materials present in the effluent that may be treated using the effluent pre-treatment system  120  disclosed herein include, for example, silicon oxide (SiO), silicon dioxide (SiO 2 ), silane (SiH 4 ), disilane, silicon tetrachloride (SiCl 4 ), silicon nitride (SiN x ), dichlorosilane (SiH 2 Cl 2 ), hexachiorodisilane (Si 2 Cl 6 ), bis(t-butyl amino)silane, trisilylamine, disilylmethane, trisilylmethane, tetrasilylmethane, tetraethyl orthosilicate (TEOS) (Si(OEt) 4 ), disiloxanes, such as disiloxane (SiH 3 OSiH 3 ), trisiloxane (SiH 3 OSiH 2 OSiH 3 ), tetrasiloxane (SiH 3 OSiH 2 OSiH 2 OSiH 3 ), and cyclotrisiloxane (—SiH 2 OSiH 2 OSiH 2 O—). Examples of tungsten-containing materials present in the effluent that may be abated using the methods disclosed herein include, for example, W(CO) 6 , WF 6 , WCl 6 , or WBr 6 . Examples of titanium-containing materials present in the effluent that may be abated using the methods disclosed herein include, for example, TiCl 4  and TiBr 4 . Examples of aluminum-containing materials present in the effluent that may be abated using the methods disclosed herein include, for example, trimethyl aluminum. 
         [0027]    One or more abating agents may be introduced in the effluent exiting the vacuum processing chamber into the effluent pre-treatment system  120  from the treatment reagent source  114 . The treatment reagent source  114  may have an isolation valve  244  and a reagent mass flow controller (MFC)  242 . The isolation valve  244  may be configured to quickly shut down the flow of reagents. The reagent MFC  242  may provide discrete amounts of constituent gases to combine as a reagent suitable for the effluent of the vacuum processing chamber  190 . The amount of reagent flow provided by the reagent MFC  242  and the operation of the isolation valve  244  may be controlled by the controller  100 , that also controls the operation of other components in the effluent pre-treatment system  120 . 
         [0028]    The regents introduced into the effluent pre-treatment system  120  from the treatment reagent source  114  may include, for example, CH 4 , H 2 O, H 2 , NF 3 , SF 6 , F 2 , HCl, HF, Cl 2 , HBr, H 2 , H 2 O, O 2 , N 2 , O 3 , CO, CO 2 , NH 3 , N 2 O, CH 4 , and combinations thereof. The abating agent may also include a combination of CH x F y  and O 2  and/or H 2 O, and a combination of CF x  and O 2  and/or H 2 O. Different abating agent may be used for effluent having different compositions. 
         [0029]    Additionally, a water distribution system (WDS)  250  may be introduced in the effluent exiting the vacuum processing chamber into the effluent pre-treatment system  120 . The WDS  250  may have a WDS isolation valve  254  and a water mass flow controller (MFC)  252 . The WDS isolation valve  254  may be configured to quickly open or shut the flow of water. The water MFC  252  may provide a controlled amount of water, or steam, to combine with the effluent of the vacuum processing chamber  190 . The operation of the water MFC  252  and WDS isolation valve  254  may be controlled by the controller  100 , that also controls the operation of other components in the effluent pre-treatment system  120 . 
         [0030]    The MFCs, such as MFCs  252 ,  242 , control the flow of fluids into the effluent pre-treatment system  120  and may tailor flows to a predefined process recipe. The MFCs  252 ,  242  may operate in response to analogue or digital signals from the controller  100 . The MFCs  252 ,  242  may have a response time between about 0.5 second to about 2 second to arrive at within 90% of setpoint, depending upon the specific models used. The MFCs  252 ,  242  may operate on a +/−15VDC power supply. 
         [0031]    The water and reagents are introduced into the effluent traveling through the foreline  192 . A pressure sensor  248  may monitor the pressure in the foreline  192  to ensure the gas mixture pressure is within the limitations of the treatment process and equipment tolerances. The pressure regulating module  182  on the exhaust conduit  194  may have a sensor  285  for monitoring the pressure in the exhaust conduit  194  to ensure equipment safety and proper treatment of the effluent. The sensor  285  may be part of the pressure regulating module  182  and provide feedback for the operation of the pressure regulating module  182  to the controller  100 . The controller  100  utilizes the information from the sensor  285  to control the operation of the pressure regulating module  182 . 
         [0032]    The flow of the gas mixture may be pulled by a vacuum pumping system  296  through the plasma reactor  210 . The flow, shown by arrow  110 , may split into two streams  110 A and  110 B in the plasma reactor  210  by a center portion  203  of the body  202  and then recombine to stream  110 C when exiting the body  202  of the plasma reactor  210  at the second opening  222 . The two streams  110 A and  110 B of the gas mixture may be dissociated by the plasma formed in the plasma reactor  210  prior to exiting as a less hazardous material through the second opening  222 . The vacuum pumping system  296  may have a sensor  299  for monitoring the vacuum pumping system  296 . The sensor  299  may provide information regarding the operation of the vacuum pumping system  296  to the systems controller, or by the controller  100  of the effluent pre-treatment system  120 . In response to the information provided by the sensor  299 , the controller (or controller  100 ) may control the operations of the vacuum pumping system  296 . 
         [0033]    The effluent pre-treatment system  120  may also contain an abatement system  298  disposed on the exhaust conduit  194  or the foreline  192 . The abatement system  298  may further introduce chemicals, temperatures or other suitable processes to end, reduce, or lessen a hazard associated with the effluent. The abatement system  298  may have a sensor  299 . The sensor  299  may have unidirectional or bidirectional communication and provide a state of the abatement system  298 , i.e., an on or off state, or operation parameters to the abatement system  298  such as temperature or chemical flow information. The sensor  299  may be coupled to the controller  100 , which utilizes the information to control the operation of other components in the effluent pre-treatment system  120 . 
         [0034]    The controller  100  includes a housing, such as a sheet metal housing, a Printed Circuit Board Assembly (PCBA), a display, a human interface such as a mouse, keyboard, touch screen, or other method for a user to interact with the controller  100 . The controller  100  also has firmware for supporting all hardware connected thereto. The controller  100  may have non-volatile memory for storage of programmatic commands and data from the plurality of sensors interacting with the controller  100 . The mass memory may additionally support data and error logging functions. 
         [0035]    The controller  100  of the effluent pre-treatment system  120  may be connected to a power source  288 , such as an alternating current (AC) generator or other suitable power source for providing electrical energy for operation of the controller  100 . Alternately, the power source  288  may be direct current (DC) power supply such as a battery or fuel cells. The energy provided to the controller  100  by the power source  288  may be coupled with fuses and filtering to protect the controller  100 . The power source  288  may provide energy to multiple controllers or other devices along with the energy supplied to controller  100 . For example, the power source  288  may be a “universal input” switching power supply and provide about 50 Watts at 24 VDC output. A link  286  between the controller  100  and the power source  288  may be a smart link providing state information for the power source  288  and control of the power source  288  as well. The controller  100  may also have a backup power supply (not shown) provided at the controller  100  to provide adequate time for the controller  100  to respond to a power failure. The controller  100  has a high efficiency design for low power operation at about 4 watts aside from output drive requirements. 
         [0036]    The controller  100  may have input and output (IO) ports  280  for communication and controlling at least the effluent pre-treatment system  120 . The IO ports  280  may include analogue IO ports  282 . In one example, the controller  100  may have at least 32 analog control outputs, operating at about 0-10 volts, to drive the MFCs  252 ,  242  or commands to the RF generator  230  through the generator sensor  234 . Additionally, the controller  100  may have at least 8 analog control inputs, for example 8 analog control inputs, operating at about 0-10 volts, may sense flows at the sensors  248 ,  299  or the RF output from the RF antenna  236  measured at the RF sensor  235 . 
         [0037]    The IO ports  280  may additionally include digital IO ports  281 . The controller  100  may have at least 24 digital control inputs (isolated), such as 56 digital control inputs; at least 8 digital programmable driver outputs, open collector; at least 8 program-defined digital control inputs (isolated); 1 or more Device Net (DNET) interface with one or more port connections and data link status indicators. The controller  100  may have 2 or more serial I/O ports for setup, monitoring or diagnostics, 8 or more LED indicators for providing the connection status of the MFCs, such as MFCs  252 ,  242 . 
         [0038]    The controller  100  may additionally have network interfaces such as Bluetooth, RJ11, RJ 45, 8011.x or other suitable means of communicating with external devices. The controller  100  may additionally have an interlock loop  284  for detecting and responding to undesired states in various devices controlled by the controller  100 . The digital IO ports  218  may include digital network ports, among others, and operate over either a single dual channel. The analogue IO ports  282  may include interfaces for the command and pressure sensor signals. 
         [0039]    The controller  100  may communicate with one or more of the pressure sensor  248  to monitor the pressure in the foreline  192 ; the pressure sensor  299  to monitor the pressure in the exhaust conduit  194 , the temperature sensor  208  to monitor the temperature of the plasma reactor  210 , or other sensors in the effluent pre-treatment system  120  to make decisions and determine system operations. For example, the controller  100  may determine a temperature is too high from the temperature sensor  208  and make adjustments to the plasma reactor  210  to protect system components therein. In a second example, the sensor  206  may signal an open state for the door  204  to the controller  100  and the controller  100  may send a command to the generator sensor  234  to cease power transmission from the RF generator  230  to the RF antenna  236  in order to prevent an injury to an operator or other person from the electrical hazard. 
         [0040]    The controller  100  is fully programmable to create a set of sequences for treating the effluent from the vacuum processing chamber  190 . The program sequences may be formed for individual effluent recipes. The effluent recipes may correspond to one or more process recipes. Thus, each process recipes which exhaust a hazardous effluent gas may have a treatment recipe directed to the gases forming the hazardous effluent gas. The controller  100  may support sixteen (16) or more programming sequences to accommodate the various treatment recipes utilized for the hazardous effluent gases from the various process recipes. The programming sequences may be changed by means of a simple text editor, or a purpose-made sequence editor GUI. Each programming sequence may have up to 15 instructions sequences which form a recipe for treating the effluent. For example, the program sequences form a recipe in the controller  100  which may have functions for enabling gas flows (set point and enable); RF Power (set point and enable); loops, duration of events; fault trapping; interlock logging; and event logging among other functions.  FIG. 4  shows an example sequence program  400  which may be utilized by the controller  100 . 
         [0041]    The sequence program  400  shown in  FIG. 4  begins in an idle state at instruction sequence  410 . The sequence program  400  waits for a run command and upon receiving a run command, moves to instruction sequence  420 . At instruction sequence  420 , NH 3  is flowed into the plasma reactor  210  for a predetermined period of time, for example about 1 second. At instruction sequence  430 , the RF generator  230  provides energy to the RF antenna  236  for generating RF energy in the plasma reactor  210 . At instruction sequence  440 , a loop is executed, such as a do while loop. The sequence program  400  remains at instruction sequence  440  until the program receives an instruction to halt or continue onto instruction sequence  450 . For example, the sequence program  400  may receive a fault which halts the sequence program  400  or the sequence program  400  may receive a stop or other instruction to move to instruction sequence  450 . At instruction sequence  450 , the NH 3  is turned off and there is a delay, for example of about 1 second, prior to moving to instruction sequence  460 . At instruction sequence  460 , the RF power is turned off and the sequence program  400  re-enters the idle state at instruction sequence  410 . Additionally, if a limit is exceeded, such as a high temperature limit from the temperature sensor  208 , anywhere during the sequence program  400 , the sequence program  400  will execute the conditions specified in the instruction sequence  410 , or other specified sequence, and halt to an idle state. 
         [0042]    Within the control fields of each instruction sequence, many items can be specified as “limits” that cause the instruction sequence to be exited to the next instruction in the sequence. The majority of limit items can also be tagged as “faults” which will cause the instruction sequence to be halted and the controller fault state to be entered. Faults (and changes of state in general) may be indicated on the hardware interface by an LED or display. The indicator may display a running status and turn off at the fault and display a fault line to indicate an error has occurred. 
         [0043]    In one example, if a fault is detected, the controller  100  may issue an alert. The alert may be an audible, visual, and/or electronic flag. For example, the controller  100  may issue an audible alert by generating an audible warning signal, such as a siren. In another example, the controller  100  may issue a visual alert by generating a visual warning signal, such as a strobe. In yet another example, the controller  100  may issue an electronic alert by generating an electronic signal, such as a text message, electronic mail or other digital communication signal. 
         [0044]      FIG. 3  is a block diagram of the controller  100  according to one embodiment. The controller  100  may have a unique read-only ID serial number of 64 bits or optionally 128 bits and additionally an internal real time clock with power backup. The controller  100  has a microcontroller (MCU)  350  for running the programs and communicating with attached devices. The MCU  350  contains a processor core, memory, and programmable input/output peripherals. For example, the MCU  350  may have about 128 kb of flash memory, 4 kb of EEPROM and 4 kb of RAM. The MCU  350  may be programmed, erased, and reprogrammed. The MCU  350  may be attached to expansion non-volatile random-access memory (NVRAM), such as recipe memory  334  and log memory  336 . 
         [0045]    The recipe memory  334  may be about 32 kb NVRAM and store the sequence programs the MCU  350  executes for treating the effluent from the processing system. The recipe memory  334  stores recipes for treating the effluent as well as controller  100  setup information. The recipe memory  334  may be configured to store 16 or more named recipes in storage. Each recipe may contain a number of instructions, for example about 15 instructions, including a jump/loopback (with counter) option for repeating instructions or sequences. The recipe may contain a recipe name (ASCII, up to 32 characters) and a recipe date stamp (when it was last uploaded or modified). Each of the 16 instructions within the recipe may contain output drive DO pattern (valve and RF enables and other control bits), output drive RF power or analog MFC flow command (4 channels*), DNET communications for DNET-capable MFCs (up to 63 devices), high and low tolerance limits for four analog return signals, disposition/option flags for excursions (example- abort, warn, log only), and a “next” step pointer for looping functions with count limit (if the count limit is 0, the sequence defaults to the next higher-numbered step). The individual counters and flags for each step to allow nested loops while duration increments for the instruction may be set at 0.1 second intervals. 
         [0046]    The log memory  336  may be about a 128 kb NVRAM and store customizable information regarding the operation of the controller  100  and the treatment system. Multiple log entry returns or resets are from the specified starting point backwards in time by the number of returns requested. Each individual log entry may be 16 bytes in length. The log entries may be reset. Resetting the log entry may include all of the error log contents, counters and pointers and formats the storage areas that contain them. The log entries intervals and content may be customizable to conserve space in the log memory  336 . In one embodiment, the material entering the logs may be modified, or filtered, to only record error handling and program sequence stops. The log memory may store recorded historical/cumulative data, for example such as one or more of: date in service (first process exposure); accumulated process time in hours (time actively running recipes); accumulated RF on time in hours; accumulated power-on time in hours; number of recipe cycles completed successfully for each recipe type; the number of recipe cycles aborted (some error or unexpected event occurred during the recipe) for each recipe type; and error counters including: RF errors, MFC errors, interlock errors, cycle aborts (from tool controller), over-temp errors, and pressure errors. Additionally, the log memory  336  may store error/event records which, for example, may include one or more of: time/date stamp, recipe and step numbers error codes indicating the type of error. For example, the log entry may have an “error code” of 0000 which may mean that the sequence stopped normally, as when all steps have been completed without failures. Items that exceed limits within the sequence step definitions will cause running sequence steps to exit or halt and an error code is stored in the log memory  336 . Examples of controller error messages may include: Sequence ended normally; Sequence has started; Purge N2 flow fault; Purge CDA flow fault; WDS fault; Reagent 0 rate mismatch; Reagent 1 rate mismatch; Reagent 2 rate mismatch; Reagent 3 rate mismatch; RF generator power mismatch; RF generator internal fault; Vacuum overpressure; Foreline overpressure; Reagent 0 overpressure; Reagent 1 overpressure; Body over-temp limit; Insufficient cooling water flow; Main door open fault; Gas box cover open fault; Gas box exhaust fault; Sequence DI fault; or Sequence Al fault. However, it should be understood that the list is by no means exclusive and is shown for reference purposes only. Up to 1024 cumulative errors/events scan be logged, FIFO, in the log memory  336 . 
         [0047]    A display  326  may be attached to the controller  100 . The display  326  may be a liquid crystal display (LCD), a light-emitting diode display (LED), or other display type. In one embodiment, the controller  100  has an LCD display  326 . The LCD display  326  may provide an alpha-numeric display for status and information. The display  326  may have 4 lines of 20 characters or 4 lines of 40 characters depending on available space for the display  326 . A GUI interface may be available on the display  326  for easy user programming of the controller  100 . The controller  100  has the capability of naming and scaling devices and their data items for viewing on the display  326 . For example, the RF generator  230  could be defined as: “RF gen 1” and its command output and feedback input scaled to display as “xxxxxW” rather than “0-100%”. 
         [0048]    Indicator LEDs  340  may be attached to the MCU  350  for providing status information. The indicator LEDs  340  may also interact with interlock logic  342 . The interlock logic  342  may receive messages  364  from limit switches indicating a state or conditions in the treatment system. For example, the sensor  206  of the door  204  may send a message  364  to the interlock logic  342  indicating an open state for the door  204  and the indicator LED  340  for the switch may display notification of the open state. The indicator LEDs  340  may be provided for one or more of DC power on indicator, such as the generator sensor  234  being on; the cover interlock indicator, such as the sensor  206  indicating an open and/or closed state of the door  204 ; the over-temperature interlock indicator, such as temperature sensor  208 , the pressure interlock indicator, such as pressure sensor  248 ; and a general health/fault indicator, among other indicators/sensors. The indicator LEDs  340  may provide a color indicator for the status or state of the item associated with the indicator. For example, the indicator LED  340  indicating the DC power may show a green color to signal the DC power is “OK” or a red color to signal a problem with the DC power. In a second example, the temperature sensor  208  may send a message  364  to the controller  100 . The interlock logic  342  may determine from the message  364  an over-temperature condition exists and change the green color to red for the corresponding the indicator LED  340 . 
         [0049]    A power supply  332  provides power to at least the MCU  350 . The power supply  332  may also provide power to the RF generator  230 . Alternately, the RF generator  230  may be part of the power supply  332 . The power supply  332  may provide about 85 VAC to about 265 VAC power at about 43 to about 63 Hz through a fused connector and switch to the controller  100 . The controller  100  may transform the power to a direct current and provide several power options to connected devices. For example, the controller may provide a 24 VDC output  271 , a 15 VDC output, a −15 VDC output, and a common leg  274  or ground. In this manner, active devices may be powered by the controller  100 . 
         [0050]    The controller  100  has the capability to automatically enter a low power, or “sleep” state when inactive for a period of time. At power-up or whenever an active program sequence ends (whether normal, aborted, or at errors) all analog outputs may revert to zero volts and the digital outputs revert to a state that is user-defined. However, after some period of user-defined inactivity, a different user-defined voltage for the digital outputs may be applied. The user may therefore define both short-term (idle) and long-term (inert) states as needed. This allows for maximum flexibility rather than simply turning everything off. If a program sequence is started before the controller  100  enters the inert state, execution of the sequence begins immediately from the idle state. If a program sequence is started when the controller is in the inert state, execution of the user defined voltage pattern is applied and the sequence begins immediately. It is the responsibility of the sequence programmer to allow for adequate wakeup time for hardware if required. 
         [0051]    Serial command ports  360  are provided on the controller  100  to handle data transfers, program transfers and other serial commands to the MCU  350 . The serial command ports  360  may include device net (DNET) ports  320  as well as one or more serial input/output ports (SIO)  322 ,  324 . The DNET port  320  may be on a single DNET channel used to interconnect devices for data exchange on the controller  100 . The single DNET channel may connect to a host system controller as well as the effluent pre-treatment system  120 . One or more drops, i.e., wired connections, may contain other controllers, other MFCs, chamber controllers, robot controllers and so forth. Separate drops may be provided for the effluent pre-treatment system  120  and the host system with each having a unique address. Advantageously, the DNET network provides a robust interface for up to 63 devices while still having a small footprint on the controller  100 . 
         [0052]    The two SIO ports  322 ,  324  on the controller  100  may be electrically-isolated RS-232 ports, i.e., the ports  322 ,  324  are isolated and have no ground loops. The first SIO port  322 , com  1 , is mainly used as a command and general communications interface to and from a host system controller. The first SIO port  322  allows the host controller (or configuration programs) to access information contained inside the controller  100 , and to program its functions including process sequence selection. The second serial SIO port  324 , com  2 , is primarily for service, i.e., updates, and data operations. The second serial SIO port  324  may be configured to provide streaming data during sequences (a setup option) and other data upon demand. In one embodiment, the data is streamed at speed of at least 57.6 K baud and may even be streamed higher than 230.4 K baud. 
         [0053]    The I/O ports  280  are available on the controller  100  for device communication outside the DNET port  320 . The I/O ports  280  may include channels for one or more of output drives, command inputs, interlock/safety sensor inputs (temperature, pressure, covers, RF generator status, etc.), MFCs (water and gas) and RF. The MFCs and RF generator connections may be connected using DSUB-9M pin connector ports (serial) on the I/O ports  280 . Advantageously, the DSUB-9M have less expensive wiring requirements then conventional ports, are interchangeable, and easily assigned in the sequences for programming functionality into the controller  100  for operating the effluent pre-treatment system  120 . Additionally, the I/O ports  280  may include connections using DA-15 (parallel) connectors which are optically isolated. In one embodiment, the RF generator ramps up or down within 0.1 second or so from the command input from MCU  350  over the I/O ports  280 . 
         [0054]    I/O ports  280 , in one example, may have four total analog devices being controlled (MFCs, RF generators, mix and match) by the controller  100 . Outbound communications to the MFCs may be on an analog output channel  348 . Inbound communications to the MFCs may be on an analog input channel  346 . Analog input channel  346  and analog output channel  348  are collectively shown as analog I/O ports  282  in  FIG. 2 . Additionally, the I/O ports  280  may include as many as 8 digital I/O ports  281 . The digital I/O ports  281  may accept both outbound and inbound communication. 
         [0055]    The MCU  350  may have isolated inputs  328  and isolated outputs  330 . The isolated inputs  328  and the isolated outputs  330  may be electrically-isolated to prevent ground loop issues. The isolated outputs  330  may provide notification of an Error/Fault  386  or a Run/Stop  388  from the MCU  350 . The isolated outputs  330  signal an override or execution of program sequence commands, such as halting the operation due to an error or fault. The isolated inputs  328  may include recipe selection  382  and run enable  384 . A user may scroll through a recipe selection  382  and select the recipe appropriate for the effluent from the vacuum processing chamber  190 . Upon selecting the appropriate recipe, the user selects run enable  384  to begin execution of the recipe on the MCU  350  of the controller  100 . 
         [0056]    The controller  100  has the capability for at least two means of sequence/recipe selections. These may be changed at any time, and by automated means. Therefore the wafer processing equipment (or other device) that utilizes the pre-treatment system  120  can select the stored sequence that is required “on the fly”, and/or program new sequences at will. For example, a host control system may select between any of the stored recipes and initiate the chosen sequence by means of selector input lines, such as isolated inputs  328 , or serial command port  360 , including the DNET port  320 . 
         [0057]    Advantageously, the controller  100  operates using one of pre-stored program sequences (recipes), and in one example, includes up to sixteen pre-stored program sequences (recipes). Up to four mass flow controllers and up to two RF generators can be controlled by the controller  100  as well. Parallel, serial, and Device Net interfaces may be used for interfacing to the processing system controller or other “feed” device controller. Interlock and safety loops are implemented using hardware methods and monitored by the controller  100  as well. The controller  100  allows the effluent pre-treatment system  120  to starts if all the necessary interlocks and conditions for running are met. If an interlock, such as the sensor  206  of the door  204 , or running condition, such as a temperature threshold determined by the temperature sensor  208 , changes, the controller  100  stops any currently running program sequence regardless of the sequence number specified in the command and returns to a safe idle state, i.e., the RF generator and reagent gasses are turned off. The inputs for interlocks and running conditions must be satisfied for the program sequences to restart. The controller  100  logs the operation thereof as well as faults and errors for safety purposes, operational tweaking, and maintenance of the entire system. 
         [0058]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.