Patent Publication Number: US-10770263-B2

Title: Methods and systems for determining a fault in a gas heater channel

Description:
CLAIM OF PRIORITY 
     The present patent application is a continuation of and claims the benefit of and priority, under 35 U.S.C. § 120, to U.S. patent application Ser. No. 15/965,497, filed on Apr. 27, 2018, and titled “Methods and Systems for Determining a Fault in a Gas Heater Channel”, which is a continuation of and claims the benefit of and priority, under 35 U.S.C. § 120, to U.S. patent application Ser. No. 14/802,876, filed on Jul. 17, 2015, titled “Methods and Systems for Determining a Fault in a Gas Heater Channel”, and now issued as U.S. Pat. No. 9,960,009, both of which are incorporated by reference herein in their entirety for all purposes. 
    
    
     FIELD 
     The present embodiments relate to systems and methods for determining a fault in a gas heater channel. 
     BACKGROUND 
     Plasma systems are used to perform various operations on a wafer. For example, the plasma systems are used to clean the wafer, etch the wafer, or deposit materials on the wafer. 
     To perform the operation, a gas is supplied to a plasma chamber. The gas is heated before being provided to the plasma chamber. 
     It is in this context that embodiments described in the present disclosure arise. 
     SUMMARY 
     Embodiments of the disclosure provide apparatus, methods and computer programs for determining a fault in a gas heater channel. It should be appreciated that the present embodiments can be implemented in numerous ways, e.g., a process, or an apparatus, or a system, or a piece of hardware, or a method, or a computer-readable medium. Several embodiments are described below. 
     In one embodiment, a system for identifying a heater element of a gas heater channel is described. The gas heater channel includes two heater elements. The system includes a voltage measurement device and a current measurement device. The voltage measurement device is connected in parallel to each heater element of the gas heater channel and the current measurement device is connected in series to the gas heater channel Such connections of the measurement devices facilitate identification of a heater element that is inoperational, e.g., is open, is malfunctioning, is broken, etc. A processor receives the voltage and current that are measured by the measurement devices and calculates a measured parallel resistance. The processor determines whether the measured parallel resistance is similar to a first ideal parallel resistance of the gas heater channel or a second ideal parallel resistance of the gas heater channel. The first ideal parallel resistance is calculated using an assumption that the first heater element is inoperational and the second ideal parallel resistance is calculated using an assumption that the second heater element is inoperational. Upon determining that the measured parallel resistance is similar to the first ideal parallel resistance, the processor determines that the first gas heater element is inoperational and upon determining that the measured parallel resistance is similar to the second ideal parallel resistance, the processor determines that the second gas heater element is inoperational. 
     In an embodiment, a method for determining a fault in a gas heater channel is described. The method includes receiving from one or more sensors measured parameters associated with a plurality of heater elements of the gas heater channel. The gas heater channel transfers one or more gases from a gas supply to a plasma chamber. The method further includes calculating a measured parallel resistance of the plurality of heater elements from the measured parameters, comparing the measured parallel resistance to an ideal parallel resistance of the heater elements of the gas heater channel, and determining based on the comparison that a portion of the gas heater channel is inoperational. The method includes selecting an identity of one of the heater elements from a correspondence between a plurality of identities of the heater elements and the measured parallel resistance. The selection of the identity facilitates identification of the portion of the gas heater channel having the fault. 
     In one embodiment, a method for determining a fault in a gas heater channel is described. The method includes receiving from one or more sensors measured parameters associated with a first plurality of heater elements of the gas heater channel. The gas heater channel transfers one or more gases from a gas supply to a plasma chamber. The method further includes calculating a measured parallel resistance of the first plurality of heater elements from the measured parameters associated with the first plurality of heater elements, comparing the measured parallel resistance of the first plurality of heater elements to an ideal parallel resistance of the first plurality of heater elements of the gas heater channel, and determining based on the comparison that the first plurality of heater elements is operational. The method also includes receiving from the one or more sensors measured parameters associated with a second plurality of heater elements of the gas heater channel, calculating a measured parallel resistance of the second plurality of heater elements from the measured parameters associated with the second plurality of heater elements, and comparing the measured parallel resistance of the second plurality of heater elements to an ideal parallel resistance of the second plurality of heater elements of the gas heater channel. The method includes determining based on the comparison that the second plurality of heater elements is inoperational and selecting an identity of one of the heater elements of the second plurality of heater elements from a correspondence between a plurality of identities and the measured parallel resistance of the second plurality of heater elements. The selection of the one or more identities facilitates identification of a portion of the gas heater channel having the fault. 
     In an embodiment, a system for determining a fault in a gas heater channel is described. The system includes an alternating current (AC) source configured to generate AC power, a rectifier coupled to the AC source and configured to convert the AC power into pulsing direct current (DC) power, and a transistor. The system further includes a gate drive coupled to the rectifier and to the transistor and configured to drive the transistor, a channel of heater elements, and a current sensor coupled to the transistor and to the channel of heater elements and configured to sense a current provided to the channel of heater elements. The current is provided when the transistor is driven. Each of the heater elements has a first node and a second node. The system includes a voltage sensor coupled to the first node of the heater elements and the second node of the heater elements and configured to measure voltage across each of the heater elements. The system also includes a processor coupled to the voltage sensor and the current sensor. The processor receives the voltage measured by the voltage sensor and the current sensed by the current sensor, calculates a parallel resistance from the voltage and the current, and determines whether the calculated parallel resistance is within a pre-determined threshold of an ideal parallel resistance of the heater elements. The processor further determines that a portion of the channel is inoperational upon determining that the parallel resistance is not within the pre-determined threshold of the ideal parallel resistance. The processor selects an identity of one of the heater elements from a correspondence between a plurality of identities and the calculated parallel resistance. The selection of the identity facilitates identification of the portion of the channel having the fault. 
     Some advantages of the herein described systems and methods include identifying a heater element that is inoperational by calculating the measured parallel resistance. A gas heater channel includes tens and sometimes hundreds of heater elements, and if one of those heater elements becomes inoperational, it is difficult for a user to determine which of the heater elements has become inoperational. The systems and methods described above help identify the heater element that has become inoperational. 
     Other advantages of the herein described systems and methods include providing pulsed direct current (DC) power to heater elements of a gas heater channel. The pulsed DC power is more stable compared to alternating current (AC) power and facilitates a stable measurement of voltage and current associated with the heater elements. The voltage and current are used to identify a heater element that is inoperational. Without the stability, it is difficult to identify the inoperational heater element. 
     Other aspects will become apparent from the following detailed description, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments are understood by reference to the following description taken in conjunction with the accompanying drawings. 
         FIG. 1A  is a diagram of an embodiment of a system for illustrating gas heater channels. 
         FIG. 1B  is a diagram of an embodiment of a system used to determine a fault in a gas heater channel. 
         FIG. 2A  is a diagram of an embodiment of a system to illustrate a complexity of arrangement of gas heater channels. 
         FIG. 2B  is a diagram of an embodiment of system to illustrate that pulsed direct current (DC) power is provided to gas heater channels. 
         FIG. 3A  is a diagram of an embodiment of a system to illustrate use of parallel resistance to determine whether there is a fault in a gas heater channel. 
         FIG. 3B  is a diagram of an embodiment of a system for identifying a heater element that is inoperational. 
         FIG. 3C-1  is a diagram of an embodiment of a system to illustrate identification of a sub-heater element that is inoperational. 
         FIG. 3C-2  is a diagram to illustrate identification of a sub-heater element or another sub-heater element that is inoperational. 
         FIG. 4  is a diagram to illustrate that measurements of parameters from different heater elements within a gas heater channel are used to identify one or more heater elements of the gas heater channel that are inoperational. 
         FIG. 5  is a diagram of an embodiment of a system for generating pulsed DC power and for identifying a heater element that is inoperational. 
         FIG. 6  shows embodiments of a graph to illustrate stability of pulsed DC power compared to alternating current (AC) power. 
         FIG. 7  is a diagram of an embodiment of a gas heater channel to illustrate a connection between heater elements of a gas heater channel. 
         FIG. 8  shows a diagram of an embodiment of a chemical vapor deposition (CVD) system. 
         FIG. 9  is a diagram of an embodiment of a control module for controlling processes within a plasma chamber. 
     
    
    
     DETAILED DESCRIPTION 
     The following embodiments describe systems and methods for determining a fault in a gas heater channel. It will be apparent that the present embodiments may be practiced without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present embodiments. 
       FIG. 1A  is a diagram of an embodiment of a system  100  for illustrating a number of gas heater channels  110 ,  112 A,  112 B,  112 C, and  112 D. The system  100  includes multiple stations  1 ,  2 ,  3 , and  4 , a gas source  108 , and a gas line box  114 . Examples of a station include a plasma chamber. For example, the station  1  is used to pre-clean a substrate, e.g., a semiconductor wafer, a substrate for a flat panel display, etc. The station  2  is used to deposit materials on the substrate, the station  3  is used to etch deposited materials from the substrate, and the station  4  is used to post-clean the substrate. 
     The gas source  108  is an enclosure, e.g., a gas tank, etc., that stores one or more process gases, e.g., oxygen-containing gas, a fluorine-containing gas, a nitrogen-containing gas, a combination of two or more thereof, etc. The gas line box  114  includes a flow control unit for adjusting a flow of the one or more process gases, e.g., a process gas for cleaning, a process gas for deposition, a process gas for sputtering, a process gas for etching, etc. For example, the gas line box  114  includes a driver, e.g., one or more transistors, etc., that drive a flow valve to control a flow rate of the one or more gases within the gas heater channel  110 . The driver is connected to a flow controller, e.g., a processor and a memory device, etc., and the controller provides a signal to the driver to drive the flow valve. A processor, as used herein, refers to a central processing unit (CPU), an application specific integrated circuit (ASIC), or a programmable logic device (PLD) is used, and these terms are used interchangeably herein. Examples of a memory device include a read-only memory (ROM), a random access memory (RAM), a hard disk, a volatile memory, a non-volatile memory, a redundant array of storage disks, a Flash memory, etc. 
     In an embodiment, the flow rate is controlled by a motor that is connected to a valve and the valve is controlled by the flow controller via the motor and a driver, e.g., one or more transistors, etc., of the motor. 
     A flow splitter is connected to the gas heater channel  110  to split the gas heater channel  110  into multiple gas heater channels  112 A thru  112 D. The gas heater channel  112 A supplies the one or more process gases to the station  1 , the gas heater channel  112 B supplies the one or more process gases to the station  2 , the gas heater channel  112 C supplies the one or more process gases to the station  3 , and the gas heater channel  112 D supplies the one or more process gases to the station  4 . 
     It should be noted that although four stations are illustrated in  FIG. 1A , in an embodiment, any other number of stations are connected to the gas heater channel  110  via the same number of gas heater channels. For example, the gas heater channel  110  is split into three gas heater channels to supply the one or more process gases to the stations  1 ,  2 , and  3 . In this example, the system  100  does not include the station  4 . 
     Moreover, it should further be noted that although one gas source  108  is illustrated in  FIG. 1A , in one embodiment, more than one gas source is used to supply process gases to one or more of the stations  1  thru  4 . For example, the other gas source supplies a process gas to the stations  1  and  2  and not to the stations  3  and  4 . 
     In one embodiment, a flow rate of flow of the one or more process gases flowing within each of the gas heater channels  112 A thru  112 D is controlled separately. For example, a flow valve within the gas heater channel  112 A is controlled by the flow controller in a manner described above to increase or decrease a flow rate of the one or more process gases flowing via the gas heater channel  112 A and a flow valve within the gas heater channel  112 B is controlled by the flow controller in a manner described above to adjust a flow rate of the one or more process gases flowing via the gas heater channel  112 B. 
       FIG. 1B  is a diagram of an embodiment of a system  118  used to determine a fault in a combination gas heater channel, which is a combination of the gas heater channel  110  and a gas heater channel  120 . The gas heater channel  120  is an example of any of the gas heater channels  112 A thru  112 D ( FIG. 1A ). 
     The system  118  includes the gas line box  114 , the gas heater channel  120 , a plasma chamber  124 , one or more parameter measurement device(s)  126 , an impedance matching circuit (IMC), one or more radio frequency (RF) generators, a host controller, and a display device  122 . Examples of the RF generators include a 400 kilohertz (kHz) RF generator, a 2 megahertz (MHz) RF generator, a 27 MHz RF generator, and a 60 MHz RF generator. The host controller is connected to the display device  122  via a bus. Examples of the display device  122  include a cathode ray tube (CRT) display device, a plasma display device, a light emitting diode (LED) display device, a liquid crystal display (LCD) device, etc. The flow controller, mentioned above, is an example of the host controller. 
     An example of the parameter measurement device(s)  126  includes a voltmeter and an ammeter. Another example of the parameter measurement device(s) includes an ohmmeter. 
     The plasma chamber  124  includes an upper electrode (UE) and a lower electrode (LE), on which a substrate S is placed for processing using the one or more process gases. Each of the upper electrode and the lower electrode is made of a metal, e.g., aluminum, alloy of aluminum, etc. The lower electrode is a part of a chuck, e.g., an electrostatic chuck (ESC), etc., within the plasma chamber  124 . The lower electrode faces the upper electrode. 
     In one embodiment, the upper electrode is grounded. 
     The host controller provides a signal indicating a corresponding amount of power to be generated by each of the RF generators to each of the RF generators. For example, the host controller provides a signal via a cable to the 2 MHz RF generator. The signal indicates to a digital signal processor (DSP) of the 2 MHz RF generator to control an RF supply within the RF generator to generate an RF signal having an amount of power indicated in the signal received from the host controller. Moreover, the host controller provides another signal via another cable to the 27 MHz RF generator. The signal indicates to a DSP of the 27 MHz RF generator to generate an RF signal having an amount of power indicated in the other signal received from the host controller. 
     The RF generators generate the RF signals and send the RF signals via corresponding RF cables to the impedance matching circuit. For example, the 2 MHz RF generator generates an RF signal and sends the RF signal via an RF cable to the impedance matching circuit and the 27 MHz RF generator generates an RF signal and sends the RF signal via an RF cable to the impedance matching circuit. 
     The impedance matching circuit receives the RF signals and filters the RF signals to match an impedance of a load connected to an output of the impedance matching circuit with that of a source connected to inputs of the impedance matching circuit. For example, the impedance matching circuit matches an impedance of an RF transmission line  128  that connects the impedance matching circuit to the lower electrode LE and the plasma chamber  124  with that of the RF generators and the RF cables that connect the RF generators to the impedance matching circuit. The impedance matching circuit matches the impedance of the load with that of the source to generate a modified RF signal, which is transferred via the RF transmission line  128  to the lower electrode. 
     When the one or more process gases are supplied via the gas heater channel  120  to a gap  130  between the upper electrode and the lower electrode and the modified RF signal is supplied to the lower electrode, plasma is stricken within the gap  130 . If plasma is already stricken at a time the one or more process gases are supplied to the gap  130  and the modified RF signal is transferred to the lower electrode, the plasma is maintained within the gap  130 . 
     Temperature of the one or more process gases in the combination gas heater channel is controlled by heating the one or more process gases. The combination gas heater channel includes heater elements that heat the one or more process gases. Due to a variety of reasons, e.g., overheating, excessive electrical current supply, wear and tear, etc., one or more of the heater elements of the combined gas heater channel become inoperational, e.g., malfunction, faulty, do not operate, burn and break, form an open circuit, etc. A gas heater channel includes tens or hundreds or sometimes even thousands of heater elements. It is difficult for a user to diagnose which of the heater elements is inoperational. 
     The parameter measurement device(s)  126  are connected to the combined gas heater channel to measure parameters, e.g., voltage, current, etc. For example, the ammeter measures a current that passes through any of the heater elements of the combined gas heater channel and the voltmeter measures a voltage across each of the heater elements. The current and the voltage are provided from the parameter measurement device(s)  126  to the host controller. The host controller calculates parallel resistance of the heater elements of the combined gas heater channel from the voltage and the current. From the parallel resistance, one or more of the heater elements that are inoperational are identified by the host controller and identities of the one or more of the heater elements are displayed on the display device  122  to the user. 
     It should be noted that in an embodiment, the modified RF signal is provided to the upper electrode and the lower electrode is grounded instead of grounding the upper electrode and providing the modified RF signal to the lower electrode. 
       FIG. 2A  is a diagram of an embodiment of a system  200  to illustrate a complexity of arrangement of gas heater channels  204 A and  204 B. The system  200  shows the gas heater channels  204 A and  204 B. The gas heater channel  204 A includes heater elements HEA, HEB, HEC, and other heater elements. Moreover, the gas heater channel  204 B includes heater elements HED, HEE, and other heater elements. The gas heater channel  204 A or the gas heater channel  204 B is located within the gas line box  114  ( FIG. 1A ) or outside the gas line box  114 . 
     A gas line  206 A is located within the gas heater channel  204 A and another gas line  206 B is located within the heater channel  204 B. The gas line  206 A delivers one or more process gases to one or more stations and the gas line  206 B delivers one or more process gases to one or more stations. 
     Each heater element is connected to another heater element via a connector. For example, the heater element HEA is connected to the heater element HEB via a connector C 1 . 
     Each gas heater channel  204 A and  204 B includes a large number of heater elements. When a device is connected in series to an end of the gas heater channel  204 A to determine whether the gas heater channel  204 A is inoperational, if one or more of the heater elements of the gas heater channel  204 A are inoperational, the device does not measure any current. However, when no current is measured using the device, it is difficult to determine which of the heater elements of the gas heater channel  204 A are inoperational. 
       FIG. 2B  is a diagram of an embodiment of system  220  to illustrate that pulsed direct current (DC) power is provided to gas heater channels  210 A and  210 B. The system  220  includes an alternating current (AC) power source  212 , a rectifier  218 , and the channels  210 A and  210 B. 
     The gas heater channel  210 A includes resistors R 1 , R 2 , R 3 , and R 4 , which are connected in series with each other. Moreover, the gas heater channel  210 B includes resistors R 5 , R 6 , R 7 , and R 8 , which are connected in series with each other. 
     In an embodiment, each gas heater channel  210 A and  210 B includes any other number of resistors than that illustrated using  FIG. 2B . For example, the gas heater channel  210 A includes 20 resistors connected in series and the gas heater channel  210 B includes 40 resistors in series. 
     The AC power source  212  generates AC power, e.g., sinusoidal power, power that oscillates peak-to-peak and while oscillating becomes zero, etc., and provides the AC power to the rectifier  218 . The rectifier  218  converts the AC power into pulsed DC power, which is further described below. The rectifier  218  provides a portion of the pulsed DC power via a path  216 A, e.g., a wire connection, etc., to the gas heater channel  210 A and provides the remaining portion of the pulsed DC power via a path  216 B to the gas heater channel  210 B. When the portion of the pulsed DC power is supplied to the gas heater channel  210 A, the gas heater channel  210 A operates at a temperature temp 1 . For example, temperature of one or more process gases within a gas line within the gas heater channel  210 A is temp 1 . Similarly, when the portion of the pulsed DC power is supplied to the gas heater channel  210 B, the gas heater channel  210 B operates at a temperature temp 2 . 
       FIG. 3A  is a diagram of an embodiment of a system  300  to illustrate use of parallel resistance to determine whether there is a fault in a gas heater channel  310 . The gas heater channel  310  is an example of any of the gas heater channels  110 ,  112 A,  112 B,  112 C,  112 D ( FIG. 1A ), and any other gas heater channel described herein. The system  300  includes the gas heater channel  310 , an ammeter A, a voltmeter V, and the host controller. The gas heater channel  310  includes heater elements HE 1 , HE 2 , and HE 3 . The heater elements HE 1 , HE 2 , and HE 3  are connected in series in the gas heater channel  310 . For example, the heater element HE 1  is connected via a connector to the path  216 A and is connected via a connector to the heater element HE 2 , the heater element HE 2  is connected via a connector to the heater element HE 3 , and the heater element HE 3  is grounded via a connector. As another example, the heater element HE 1  includes the resistor R 1  ( FIG. 2B ), the heater element HE 2  includes the resistor R 2  ( FIG. 2B ), and the heater element HE 3  includes the resistor R 3  ( FIG. 2B ), which is grounded. 
     In one embodiment, the gas heater channel  310  includes any other number of heater elements, e.g., two, ten, twenty, forty, sixty, hundred, two hundred, in tens, in hundreds, etc., and the heater elements are connected in series. 
     The voltmeter V is connected in parallel to a node N 1  of each of the heater elements HE 1 , HE 2 , and HE 3  and to a node N 2  of each of the heater elements H 1 , H 2 , and H 3 . Similarly, the ammeter A is connected in series with the node N 1  of any of the heater elements HE 1 , HE 2 , and HE 3 . In one embodiment, instead of the node N 1 , the ammeter A is connected in series with the node N 2  of any of the heater elements HE 1 , HE 2 , and HE 3 . The voltmeter V is connected to the nodes N 1  and N 2  of the heater elements HE 1 , HE 2 , and HE 3  by the user and the ammeter A is connected to the node N 1  of any of the heater elements HE 1 , HE 2 , and HE 3  by the user. 
     An ideal parallel resistance IPR of the gas heater channel  310  is calculated by the host controller. For example, the ideal parallel resistance IPR is calculated as:
 
IPR=1/{(1/IR1)+(1/IR2)+(1/IR3)}  (1),
 
where IR 1  is an ideal resistance of the heater element HE 1 , IR 2  is an ideal resistance of the heater element HE 2 , and IR 3  is an ideal resistance of the heater element HE 3 . The resistances IR 1 , IR 2 , and IR 3  are accessed by the host controller from a specification database, e.g., specification file, etc., which is stored in the memory device of the host controller or is accessed via a computer network, e.g., local area network, wide area network, etc., by a host computer that includes the host controller. As another example, when the gas heater channel  310  is initially installed or serviced in a plasma system to heat one or more process gases, the voltmeter V measures a voltage between the nodes N 1  and N 2 , and the ammeter A measures a current that passes through any of the heater elements HE 1 , HE 2 , and HE 3 . For example, the ammeter A measures the current at the node N 1  of the heater element HE 1  or the heater element HE 2  or the heater element HE 3 . The current and the voltage measured are provided to the host controller, which calculates a commissioned resistance, e.g., the ideal parallel resistance IPR, etc., from the current and the voltage. For example, the host controller calculates the commissioned resistance as a ratio of the voltage and current.
 
     During operation of the gas heater channel  310  in a plasma system, e.g., a period of time after the initial installation or service, a period of time after the gas heater channel  310  is used within the plasma system, after wear and tear of the gas heater channel  310 , etc., the voltmeter V measures a voltage V 1  across the nodes N 1  and N 2  of the heater elements HE 1 , HE 2 , and HE 3  and the ammeter A measures a current I 1  at the node N 1  of any of the heater elements HE 1 , HE 2 , and HE 3 . The current I 1  is a current that flows through any or all of the heater elements HE 1 , HE 2 , and HE 3 . The current I 1  is provided by the ammeter A to the host controller and the voltage V 1  is provided by the voltmeter V to the host controller. 
     The host controller calculates a measured parallel resistance MPR from the current I 1  and the voltage V 1 . For example, the host controller calculates the measured parallel resistance to be V 1 /I 1 , which is a ratio of V 1  and I 1 . The host controller compares the measured parallel resistance MPR with the ideal parallel resistance IPR to determine whether the measured parallel resistance MPR is within a predetermined threshold THRHOLD, e.g., same as, within a pre-determined range from, etc., of the ideal parallel resistance IPR. Upon determining that the measured parallel resistance MPR is within the predetermined threshold THRHOLD of the ideal parallel resistance IPR, the host controller determines that the gas heater channel  310  is operational, e.g., all the heater elements HE 1 , HE 2 , and HE 3  are operational, etc. On the other hand, upon determining that the measured parallel resistance MPR is not within the predetermined threshold THRHOLD of the ideal parallel resistance IPR, the host controller determines that the gas heater channel  310  is inoperational, e.g., a portion of the gas heater channel  310  is inoperational, etc. For example, the heater element HE 1  or the heater element HE 2 , or the heater element HE 3 , or a connector between the heater element HE 1  and the heater element HE 2 , or a connector between the heater element HE 2  and the heater element HE 3 , or a connector coupled between the heater element HE 1  and the path  216 A ( FIG. 2B ), or a connector coupled to the heater element HE 3  to ground the heater element HE 3 , or a combination of two or more thereof, etc., is inoperational. 
     In one embodiment, a heater element is inoperational when a resistor of the heater element is inoperational. In an embodiment, a connector is inoperational when a connection medium, which is described below, of the connector is inoperational. 
     It should be noted that when the voltmeter V is connected to the nodes N 1  and N 2  of the heater elements HE 1 , HE 2 , and HE 3 , the heater element HE 1  is in series with the heater element HE 2 , which is in series with the heater element HE 3 . The connection of the voltmeter V facilitates calculation of the measured parallel resistance MPR. Similarly, when the ammeter A is connected to the node N 1  of any of the heater elements HE 1 , HE 2 , and HE 3 , the heater elements HE 1 , HE 2 , and HE 3  are connected in series with each other. The connection of the ammeter A facilitates calculation of the measured parallel resistance MPR. 
     In one embodiment, the heater element HE 1  has a different resistance than that of the heater element HE 2 , and the heater element HE 2  has a different resistance than each of the heater elements HE 1  and HE 3 . For example, a resistor of the heater element HE 1  is of a different length than a length of resistor of a resistor of the heater element HE 2  and/or a cross-sectional area of the resistor of the heater element HE 1  is different than a cross-sectional area of the resistor of the heater element HE 2 . 
       FIG. 3B  is a diagram of an embodiment of a system  320  for identifying the heater element HE 1 , HE 2 , or HE 3  that is inoperational. The memory device of the host controller stores a database  306 , e.g., a correspondence, a mapping, an association, links, etc., between an identity of a heater element that is inoperational and a value of the measured parallel resistance MPR. For example, the database  306  includes a mapping between an identity ID 1  of the heater element HE 1  and a value IPR 1  of the ideal parallel resistance IPR. Moreover, the database  306  includes a mapping between an identity ID 2  of the heater element HE 2  and a value IPR 2  of the ideal parallel resistance IPR and includes a mapping between an identity ID 3  of the heater element HE 3  and a value IPR 3  of the ideal parallel resistance IPR. 
     The ideal parallel resistance IPR is calculated to be IPR 1  by the host controller when the ideal resistance IR 1  is not applied in the equation (1) by the host controller to calculate the ideal parallel resistance IPR. Similarly, the ideal parallel resistance IPR is calculated to be IPR 2  when the ideal resistance IR 2  is not applied in the equation (1) by the host controller to calculate the ideal parallel resistance IPR and the ideal parallel resistance IPR is calculated to be IPR 3  when the ideal resistance IR 3  is not applied in the equation (1) by the host controller to calculate the ideal parallel resistance IPR. The ideal parallel resistances IPR 1 , IPR 2 , and IPR 3  are stored in the database  306  by the host controller. 
     In one embodiment, the ideal parallel resistance IPR 1  is calculated when the voltmeter V is connected to the node N 1  of the heater elements HE 2  and HE 3  and not to the node N 1  of the heater element HE 1 , and is connected to the node N 2  of the heater elements HE 2  and HE 3  and not to the node N 2  of the heater element HE 1 , and the ammeter A is connected to the node N 1  of any of the heater elements HE 2  and HE 3  and not of the heater element HE 1 . Moreover, the ideal parallel resistance IPR 2  is calculated when the voltmeter V is connected to the node N 1  of the heater elements HE 1  and HE 3  and not to the node N 1  of the heater element HE 2 , and is calculated when the voltmeter V is connected to the node N 2  of the heater elements HE 1  and HE 3  and not to the node N 2  of the heater element HE 2 , and the ammeter A is connected to the node N 1  of any of the heater elements HE 1  and HE 3  and not of the heater element HE 2 . Also, the ideal parallel resistance IPR 3  is calculated when the voltmeter V is connected to the node N 1  of the heater elements HE 1  and HE 2  and not to the node N 1  of the heater element HE 3 , and is connected to the node N 2  of the heater elements HE 1  and HE 2  and not to the node N 2  of the heater element HE 3 , and the ammeter A is connected to the node N 1  of any of the heater elements HE 1  and HE 2  and not of the heater element HE 3 . 
     The host controller determines whether the measured parallel resistance MPR has a value that is within a pre-determined threshold th, e.g., same as, within a pre-determined range from, etc., of the value IPR 1 . Upon determining that the measured parallel resistance MPR has a value that is within the pre-determined threshold th of the value IPR 1 , the host controller determines that the heater element HE 1  is inoperational and accesses the identity ID 1  from the database  306  to display via the display device  122  to the user. It should be noted that when the identity ID 1  is displayed, the heater element HE 1  and/or a connector coupled to the heater element HE 1  is inoperational. 
     On the other hand, upon determining that the measured parallel resistance MPR has a value that is not within the pre-determined threshold th of the value IPR 1 , the host controller determines whether the measured parallel resistance MPR has a value that is within the pre-determined threshold th of the value IPR 2 . Upon determining that the measured parallel resistance MPR has a value that is within the pre-determined threshold th of the value IPR 2 , the host controller determines that the heater element HE 2  is inoperational and accesses the identity ID 2  from the database  306  for display via the display device  122  to the user. It should be noted that when the identity ID 2  is displayed, the heater element HE 2  and/or a connector coupled to the heater element HE 2  is inoperational. 
     Upon determining that the measured parallel resistance MPR has a value that is not within the pre-determined threshold th of the value IPR 2 , the host controller determines whether the measured parallel resistance MPR has a value that is within the pre-determined threshold th of the value IPR 3 . Upon determining that the measured parallel resistance MPR has a value that is within the pre-determined threshold th of the value IPR 3 , the host controller determines that the heater element HE 3  is inoperational and accesses the identity ID 3  from the database  306  to display via the display device  122  to the user. It should be noted that when the identity ID 3  is displayed, the heater element HE 3  and/or a connector coupled to the heater element HE 3  is inoperational. 
     It should be noted that in an embodiment, an identity of a heater element is provided to the user in the form of a sound via audio equipment, e.g., amplifier and speaker, etc., instead of or in addition to using the display device  122 . 
     In one embodiment, an identity of a heater element is transferred via the computer network to another host computer to display to the user and/or to provide to the user in the form of sound. 
       FIG. 3C-1  is a diagram of an embodiment of a system  330  to illustrate identification of a sub-heater element HE 21  or HE 22  that are portions of a combined heater element, e.g., the heater element HE 2 , etc. For example, the combined heater element includes two sub-heater elements HE 21  and HE 22  instead of being one heater element. As another example, the combined heater element includes two resistors R 21  and R 22  instead of including one resistor R 2 . The sub-heater element H 21  is connected to the heater element HE 1  via a connector and the sub-heater element H 22  is connected to the heater element HE 3  via a connector. 
     In one embodiment, the sub-heater elements HE 21  and HE 22  are connected with each other via a connector. 
     The sub-heater elements HE 21  and HE 22  are connected in series with each other and to the heater element HE 1  and to the heater element HE 3  when implemented within a channel  311 , which is an example of the channel  110 , or the channel  112 A, or the channel  112 B, or the channel  112 C, or the channel  112 D ( FIG. 1A ). For example, the combined heater element is connected via a connector to the heater element HE 1  and is connected via a connector to the heater element HE 3 . 
     The ideal parallel resistance IPR of the channel  311  is calculated in one of various manners described above of calculating the ideal parallel resistance IPR of the channel  310  except that IR 2  is a total resistance of the sub-heater elements HE 21  and HE 22  instead of being the resistance of the heater element HE 2 . Moreover, the measured parallel resistance MPR of the channel  311  is calculated in a manner described above of calculating the measured parallel resistance MPR of the channel  310 . 
     The host controller compares the measured parallel resistance MPR of the channel  311  with the ideal parallel resistance IPR of the channel  311 . Upon determining that the measured parallel resistance MPR of the channel  311  is within the pre-determined threshold THRHOLD of the ideal parallel resistance IPR of the channel  311 , the host controller determines that the heater elements of the channel  311  are operational. On the other hand, upon determining that the measured parallel resistance MPR of the channel  311  is not within the pre-determined threshold THRHOLD of the ideal parallel resistance IPR of the channel  311 , the host controller determines that the heater element HE 1 , or the sub-heater element HE 21 , or the sub-heater element HE 22 , or the heater element HE 3 , or a connector between the heater element HE 1  and the sub-heater element HE 21 , or a connector between the sub-heater element HE 21  and the sub-heater element HE 22 , or a connector between the sub-heater element HE 22  and the heater element HE 3 , or a connector between the path  216 A ( FIG. 2B ) and the heater element HE 1 , or a connector coupled to the heater element HE 3  to ground the heater element HE 3 , or a combination of two or more thereof, etc., is inoperational. 
     In one embodiment, the sub-heater element HE 21  has a different resistance than that of the sub-heater element HE 22 . For example, a resistor of the sub-heater element HE 21  is of a different length than a length of a resistor of the sub-heater element HE 22  and/or a cross-sectional area of the resistor of the sub-heater element HE 21  is different than a cross-sectional area of the resistor of the sub-heater element HE 22 . 
       FIG. 3C-2  is a diagram to illustrate identification of the sub-heater element HE 21  or the sub-heater element HE 22  that is inoperational. The voltmeter V is connected by the user to a node N 21  and a node N 22  of a sub-channel that includes the sub-heater elements HE 21  and HE 22 . Moreover, the ammeter A is connected to the node N 21  of any of the sub-heater elements HE 21  and HE 22  by the user. 
     An ideal parallel resistance IPSR of the sub-heater elements HE 21  and HE 22  is calculated by the host controller. For example, the ideal parallel resistance IPSR is calculated as:
 
IPSR=1/{(1/IR21)+(1/IR22)}  (2),
 
where IR 21  is an ideal resistance of the sub-heater element HE 21  and IR 22  is an ideal resistance of the sub-heater element HE 22 . The ideal resistances IR 21  and IR 22  are accessed by the host controller from a specification database, e.g., specification file, etc., which is stored in the memory device of the host controller or is accessed via the computer network by the host computer. As another example, when the gas heater channel  311  ( FIG. 3C-1 ) is initially installed or serviced in a plasma system to heat one or more process gases, the voltmeter V measures a voltage between the nodes N 21  and N 22 , and the ammeter A measures a current that passes through any of the sub-heater elements HE 21  and HE 22 . For example, the ammeter A measures the current at the node N 21  of any of the sub-heater elements HE 21  and HE 22 . The current and the voltage measured is provided to the host controller, which calculates a commissioned resistance, e.g., the ideal parallel resistance IPSR, etc., from the current and the voltage. For example, the host controller calculates the commissioned resistance as a ratio of the voltage and current.
 
     The ideal parallel resistance IPSR is calculated to be IPSR 21  by the host controller when the ideal resistance IR 21  is not applied in the equation (2) by the host controller. Similarly, the ideal parallel resistance IPSR is calculated to be IPSR 22  when the ideal resistance IR 22  is not applied in the equation (2) by the host controller. The ideal parallel resistances IPSR 21  and IPSR 22  are stored in a database  340  by the host controller. The database  340  is stored in the memory device of the host controller. 
     In one embodiment, the ideal parallel resistance IPSR 21  is calculated when the voltmeter V is connected to the node N 21  of the sub-heater element HE 22  and not to the node N 21  of the sub-heater element HE 21 , and is connected to the node N 22  of the sub-heater element HE 22  and not to the node N 22  of the sub-heater element HE 21 , and the ammeter A is connected to the node N 21  of the sub-heater element HE 22  and not to the node N 21  of the sub-heater element HE 21 . Moreover, the ideal parallel resistance IPSR 22  is calculated when the voltmeter V is connected to the node N 21  of the sub-heater element HE 21  and not to the node N 21  of the sub-heater element HE 22 , and is connected to the node N 22  of the sub-heater element HE 21  and not to the node N 22  of the sub-heater element HE 22 , and the ammeter A is connected to the node N 21  of the sub-heater element HE 21  and not to the node N 21  of the sub-heater element HE 22 . 
     During operation of the gas heater channel  311  in a plasma system, e.g., a period of time after the initial installation or service of the gas heater channel  311 , a period of time after the gas heater channel  311  is used within the plasma system, after wear and tear of the gas heater channel  311 , etc., the voltmeter V measures a voltage V 2  across the nodes N 21  and N 22  of the sub-heater elements HE 21  and HE 22  and the ammeter A measures a current I 2  at the node N 21  of any of the sub-heater elements HE 21  and HE 22 . The current I 2  is a current that flows through any of the sub-heater elements HE 21  and HE 22 . The current I 2  is provided by the ammeter A to the host controller and the voltage V 2  is provided by the voltmeter V to the host controller. The host controller calculates the measured parallel resistance MPSR as a ratio of the voltage V 2  and the current I 2 . 
     The database  340  includes an identity of a sub-heater element that is inoperational and a value of the measured parallel resistance MPSR. For example, the database  340  includes a mapping between an identity ID 21  of the sub-heater element HE 21  and the value IPSR 21  of the ideal parallel resistance IPSR. Moreover, the database  340  includes a mapping between an identity ID 22  of the sub-heater element HE 22  and a value IPSR 22  of the ideal parallel resistance IPSR. 
     The host controller determines whether the measured parallel resistance MPSR has a value that is within a pre-determined range rnge, e.g., same as, within a pre-determined limit from, etc., of the value IPSR 21 . Upon determining that the measured parallel resistance MPSR has a value that is within the pre-determined range rnge of the value IPSR 21 , the host controller determines that the sub-heater element HE 21  is inoperational and accesses the identity ID 21  from the database  340  to indicate via the display device  122  ( FIG. 1B ) to the user that the sub-heater element HE 21  is inoperational. It should be noted that when the identity ID 21  is displayed, the sub-heater element HE 21  and/or a connector coupled to the sub-heater element HE 21  is inoperational. 
     On the other hand, upon determining that the measured parallel resistance MPSR has a value that is not within the pre-determined range rnge of the value IPSR 21 , the host controller determines whether the measured parallel resistance MPSR has a value that is within the pre-determined range rnge of the value IPSR 22 . Upon determining that the measured parallel resistance MPSR has a value that is within the pre-determined range rnge of the value IPSR 22 , the host controller determines that the sub-heater element HE 22  is inoperational and accesses the identity ID 22  from the database  340  for display via the display device  122  to the user. It should be noted that when the identity ID 22  is displayed, the sub-heater element HE 22  and/or a connector coupled to the sub-heater element HE 22  is inoperational. 
     It should be noted that in an embodiment, an identity of a sub-heater element is provided to the user in the form of a sound via the audio equipment instead of or in addition to using the display device  122 . 
     It should further be noted that when the voltmeter V is connected to the nodes N 21  and N 22 , the sub-heater element HE 21  is in series with the heater element HE 22 . The connection of the voltmeter V facilitates calculation of the measured parallel resistance MPSR. Similarly, when the ammeter A is connected to the node N 21 , the sub-heater element HE 21  is in series with the sub-heater element HE 22 . The connection of the ammeter A facilitates calculation of the measured parallel resistance MPSR. 
     In one embodiment, an identity of a sub-heater element is transferred via the computer network to another host computer to display to the user and/or to provide to the user in the form of sound. 
       FIG. 4  is a diagram to illustrate that measurements of parameters from different heater elements within a gas heater channel  410  are used to identify one or more heater elements of the gas heater channel  410  that are operational. The gas heater channel  410  includes the heater element HE 1 , the heater element HE 2 , the heater element HE 3 , a heater element HE 4 , and a heater element HE 5 . The heater element HE 1  is connected in series with the heater element HE 2 , the heater element HE 2  is connected in series with the heater element  3 , the heater element  3  is connected in series with the heater element  4 , and the heater element HE 4  is connected in series with the heater element HE 5 . The heater element HE 5  is grounded. 
     In one embodiment, the gas heater channel  410  includes any other number of heater elements, e.g., ten, twenty, in tens, in hundreds, etc. 
     The user connects the ammeter A to the node N 1  of the heater element HE 1  and connects the voltmeter V to the nodes N 1  and N 2  of the heater elements HE 1 , HE 2 , and HE 3 . As explained above with reference to  FIGS. 3A and 3B , the host controller then determines whether a portion, e.g., a segment, etc., of the gas heater channel  410  that includes the heater elements HE 1 , HE 2 , and HE 3  is operational. Upon determining that the portion of the gas heater channel  410  that includes the heater elements HE 1 , HE 2 , and HE 3  is inoperational, the heater element HE 1 , or the heater element HE 2 , or the heater element HE 3  is identified by the host controller. 
     On the other hand, upon determining that the portion that includes the heater elements HE 1 , HE 2 , and HE 3  is operational, the user removes the connection of the voltmeter V from the nodes N 1  and N 2  of each of the heater elements HE 1 , HE 2 , and HE 3 . Also, the user removes the connection of the ammeter A from the node N 1  of the heater element HE 1 . The user then connects the voltmeter V to the nodes N 1  and N 2  of the heater elements HE 4  and HE 5 , and connects the ammeter A to the node N 1  of the heater element HE 4  or of HE 5 . 
     Then, in a manner similar to that explained above with reference to  FIGS. 3A and 3B , the host controller then determines whether a portion, e.g., a segment, etc., of the gas heater channel  410  that includes the heater elements HE 4  and HE 5  is operational. Upon determining that the portion of the gas heater channel  410  that includes the heater elements HE 4  and HE 5  is inoperational, the heater element HE 4  or the heater element HE 5  is identified by the host controller. 
       FIG. 5  is a diagram of an embodiment of a system  500  for generating pulsed DC power and for identifying a heater element that is inoperational. The system  500  includes a rectifier  514 , a voltage sensor  520 , a filter  522 , a processor  524 , gate drives  518 , transistors  516 A,  516 B, and  516 C, current sensors  520 A,  520 B, and  520 C, and gas heater channels  510 A,  510 B, and  510 C. An example of each of the gate drives  518  includes a transistor. 
     The rectifier  514  is an example of the rectifier  218  ( FIG. 2B ), the voltage sensor  520  is an example of the voltmeter V, and the processor  524  is an example of the processor of the host controller. Also, any of the current sensors  520 A,  520 B, and  520 C is an example of the ammeter A. Moreover, the gas heater channel  510 A is an example of the gas heater channel  110  or of the gas heater channel  112 A or of the gas heater channel  112 B or of the gas heater channel  112 C or of the gas heater channel  112 D. Also, the gas heater channel  510 B is an example of the gas heater channel  110  or of the gas heater channel  112 A or of the gas heater channel  112 B or of the gas heater channel  112 C or of the gas heater channel  112 D. Moreover, the gas heater channel  510 C is an example of the gas heater channel  110  or of the gas heater channel  112 A or of the gas heater channel  112 B or of the gas heater channel  112 C or of the gas heater channel  112 D. 
     The AC power source  212  ( FIG. 2B ) supplies AC power to the rectifier  514 . The rectifier  514  rectifies, e.g., converts, etc., the AC power into a pulsed DC power  504 . A first portion of the pulsed DC power  504  is supplied via an ND 1  bus  530 A and a bus  532 A to the gas heater channel  510 A, a second portion of the pulsed DC power  504  is supplied via the ND 1  bus  530 A and a bus  532 B to the gas heater channel  510 B, and a third portion of the pulsed DC power  504  is supplied via the ND 1  bus and a bus  532 C to the gas heater channel  510 C. 
     It should be noted that the filter  522  filters the pulsed DC power to generate smooth pulsed DC power, which is provided to the processor  524 . The processor  524  sends control signals to the gate drives  518 . One of the gate drives  518  generates a power signal upon receiving one of the control signals and provides the power signal via a gate  534 A to the transistor  516 A. Similarly, another one of the gate drives  518  generates a power signal upon receiving another one of the control signals and provides the power signal via a gate  534 B to the transistor  516 B. Also, yet another one of the gate drives  518  generates a power signal upon receiving another one of the control signals and provides the power signal via a gate  534 C to the transistor  516 C. 
     Upon receiving the power signal via the gate  534 A, the transistor  516 A is activated and the transistor  516 A transfers the portion of the pulsed DC power received via the bus  532 A and the current sensor  520 A to the gas heater channel  510 A, which includes heater elements  540 A,  540 B,  540 C, and  540 D. The heater elements  540 A,  540 B,  540 C, and  540 D generate heat upon receiving the portion of the pulsed DC power  504  to heat one or more process gases within a gas line within the gas heater channel  510 A. 
     Similarly, upon receiving the power signal via the gate  534 B, the transistor  516 B is turned on and transfers the portion of the pulsed DC power received via the bus  532 B and the current sensor  520 B to one or more heater elements of the gas heater channel  510 B. The one or more heater elements of the gas heater channel  510 B generate heat upon receiving the portion of the pulsed DC power  504  to heat one or more process gases within a gas line within the gas heater channel  510 B. 
     Also, upon receiving the power signal via the gate  534 C, the transistor  516 C is turned on and transfers the portion of the pulsed DC power received via the bus  532 C and the current sensor  520 C to one or more heater elements of the gas heater channel  510 C. The one or more heater elements of the gas heater channel  516 C generate heat upon receiving the portion of the pulsed DC power  504  to heat one or more process gases within a gas line within the gas heater channel  510 C. 
     The heater elements  540 A,  540 B,  540 C, and  540 C are connected in series with each other. For example, an output of the heater element  540 A is connected to an input of the heater element  540 B, an output of the heater element  540 B is connected to an input of the heater element  540 C, and an output of the heater element  540 C is connected to an input of the heater element  540 D. 
     It should be noted that although four heater elements are illustrated in the gas heater channel  510 A, in an embodiment, the gas heater channel  510 A includes any other number of heater elements. 
     The current sensor  520 A measures an amount of current that passes via the transistor  516 A to each of the heater elements  540 A,  540 B,  540 C, and  540 D of the gas heater channel  510 A. Similarly, the current sensor  520 B measures an amount of current that passes via the transistor  516 B to the one or more heater elements of the gas heater channel  510 B and the current sensor  520 C measures an amount of current that passes via the transistor  516 C to the one or more heater elements of the gas heater channel  510 C. 
     Moreover, the voltage sensor  520  measures an amount of voltage between nodes ND 1  and ND 2  and the node ND 2  is located on an ND 2  bus  530 B. The voltage is voltage between node ND 1  and node ND 2  of each of the heater elements  540 A,  540 B,  540 C, and  540 D. 
     By converting the AC power into the pulsed DC power  504 , the voltage sensor  520  measures the voltage in a reliable manner and the current sensors  520 A,  520 B, and  520 C measure the currents reliably. Moreover, the voltage measured for the gas heater channel  510 A is sent from the voltage sensor  520  to the processor  524  and the current measured for the gas heater channel  510 A is sent from the current sensor  520 A to the processor  524 . The voltage and current then are used by the processor  524  to identify one of the heater elements  540 A,  540 B,  540 C, and  540 D that is inoperational in a manner similar to that described above. 
       FIG. 6  shows embodiments of a graph  600  to illustrate stability of pulsed DC power compared to AC power. The graph  600  plots pulsed DC voltage  612 , DC pulsed power  610 , and 3-phase AC power  614  versus time t. The pulsed DC power  610  is generated from the pulsed DC voltage  612 . The 3-phase AC power  614  is generated by the AC power source  212  ( FIG. 2B ). A rectifier generates the DC pulsed power  610  from the 3-phase AC power  614 . 
     It should be noted that the 3-phase AC power  614  oscillates and becomes zero periodically. The oscillation and cycling through zero makes use of the 3-phase AC power  614  unstable and less reliable in measuring the parameters compared to use of the DC pulsed power  610  in measuring the parameters. The DC pulsed power  610  does not become zero and is more reliable than the 3-phase AC power  614 . The user of DC pulsed power  610  provides continuous power delivery, e.g., at all instances of time, etc., to heater elements of a gas heater channel and the continuous power delivery makes the measurement of the parameters more reliable compared to intermittent power delivery of the 3-phase AC power  614 . Moreover, the DC pulsed power  610  has smaller size energy packets than that of the 3-phase AC power  614  to reduce stress on a heater element to which the DC pulsed power  610  is provided. Moreover, the DC pulsed power  610  has an increased voltage compared to the 3-phase AC power  614 . For the same amount of power, the increased voltage of the DC pulsed power  610  reduces average current passing through a heater element to which the DC pulsed power  610  is provided to decrease power lost by the heater element. Furthermore, use of the DC pulsed power  610  allows use of a firing order for energizing the heater channels  510 A,  510 B, and  510 C ( FIG. 5 ) to allow for precise energy management. Also, there is no need to use a snap action over temperature switch when the DC pulsed power  610  is supplied to the heater channels  510 A,  510 B, and  510 C. 
       FIG. 7  is a diagram of an embodiment of a gas heater channel  700  to illustrate a connection between heater elements  702 A and  702 B of a gas heater channel  700 . The heater element  702 A includes a resistor  704 A and the heater element  702 B includes a resistor  704 B. The heater elements  702 A and  702 B are connected to each other via a connector  706 . The connector  706  includes a connection medium  708 , e.g., a wire, etc., that connects to the resistor  704 A at a connection point  710 A. Similarly, the connection medium  708  connects to the resistor  704 B at a connection point  710 B. The heater elements  702 A and  702 B generate heat that heats one or more process gases flowing through a gas line  720 . 
     The heater element  702 A includes a tube  712 A that encloses and surrounds the resistor  704 A. Similarly, the connector  706  includes a tube  712 B that encloses and surrounds the connection medium  708 . Also, the heater element  702 B includes a tube  712 C that encloses and surrounds the resistor  704 C. The tube  712 A fits with the tube  712 B, which fits with the tube  712 C. 
     In an embodiment, a tube is made of one or more metals, e.g., aluminum, steel, or a combination thereof, etc. 
       FIG. 8  shows an exemplary chemical vapor deposition (CVD) system  800 . A deposition of film is implemented in a plasma enhanced chemical vapor deposition (PECVD) system. The PECVD system may take many different forms. The PECVD system includes one or more plasma chambers or “reactors” (sometimes including multiple stations) that house one or more wafers and are suitable for wafer processing. Each plasma chamber houses one or more wafers for processing. The one or more plasma chambers maintain a wafer in a defined position or positions (with or without motion within that position, e.g. rotation, vibration, or other agitation). A wafer undergoing deposition may be transferred from one station to another during the process. Of course, in one embodiment, the film deposition occurs entirely at a single station or any fraction of the film is deposited at any number of stations. 
     While in process, each wafer is held in place by a pedestal, wafer chuck and/or other wafer holding apparatus. For certain operations, the apparatus may include a heater such as a heating plate to heat the wafer. For example, a reactor  802  in  FIG. 8  includes a process chamber  804 , which encloses other components of the reactor and contains plasma. The plasma may be generated by a capacitor type system including a showerhead  806  working in conjunction with a grounded heater block  808 . A high-frequency RF generator  810  and a low-frequency RF generator  814  are connected to the showerhead  806  via a matching network  812 . The power and frequency supplied by the matching network  812  is sufficient to generate plasma from a process gas. 
     Within the reactor  802 , a wafer pedestal  816  supports a substrate  818 . The pedestal  816  typically includes a chuck, a fork, or lift pins to hold and transfer the substrate during and between the deposition and/or other plasma processes. Examples of the chuck include an electrostatic chuck and a mechanical chuck. One or more process gases are introduced via an inlet  824 . Multiple source gas lines  826 A,  826 B, and  826 C are connected to a manifold  830 . One or more process gases are premixed or not. Appropriate valving and mass flow control mechanisms are employed to ensure that the correct process gases are delivered during a process. 
     Process gases exit the reactor  802  via an outlet  834 . A vacuum pump  836  (e.g., a one or two stage mechanical dry pump and/or a turbomolecular pump) draws process gases out and maintains a suitably low pressure within the reactor by a close loop controlled flow restriction device, such as a throttle valve or a pendulum valve. It is possible to index wafers after every deposition and/or post-deposition plasma anneal treatment until all the required depositions and treatments are completed, or multiple depositions and treatments can be conducted at a single station before indexing the wafer. 
     In one embodiment, the inter-electrode gap is illustrated between the showerhead  806  (powered top electrode), and the pedestal  816  (e.g., grounded electrode) over which the wafer  818  is placed. As described in more detail below, bottom electrode or top electrode may be vertically adjusted to change the gap, so as to set or achieve a desired uniformity profile during deposition. 
       FIG. 9  shows a control module  900  for controlling processes within a plasma chamber described above. The control module  900  is an example of the host controller. In one embodiment, the control module  900  includes some example components. For instance, the control module  900  includes a processor, memory and one or more interfaces. The control module  900  is employed to control devices in the plasma system based in part on sensed values. For example, the control module  900  controls one or more of valves  902 , filter heaters  904 , pumps  906 , and other devices  908  based on sensed values and other control parameters. The control module  900  receives the sensed values from, for example, pressure manometers  910 , flow meters  912 , temperature sensors  914 , and/or other sensors  916 . The control module  900  is be employed to control process conditions, e.g., during precursor delivery and deposition of a film, etc. In one embodiment, the control module  900  will typically include one or more memory devices and one or more processors. 
     The control module  900  controls activities associated with implementing the process conditions. For example, the control module  900  executes computer programs including sets of instructions for controlling process timing, delivery system temperature, pressure differentials across the filters, valve positions, mixture of gases, chamber pressure, chamber temperature, wafer temperature, RF power levels, wafer chuck or pedestal position, and other parameters of a particular process. 
     Typically, there will be a user interface associated with the control module  900 . The user interface includes a display  918  (e.g. a display screen and/or graphical software displays of the apparatus and/or process conditions), and user input devices  920  such as pointing devices, keyboards, touch screens, microphones, etc. The display  918  is an example of the display device  122  ( FIG. 1B ). 
     A computer program for controlling implementing of the process conditions can be written in any conventional computer readable programming language: for example, assembly language, C, C++, Pascal, Fortran or others. Compiled object code or script is executed by the processor to perform the tasks identified in the computer program. 
     The control module parameters relate to the process conditions such as, for example, filter pressure differentials, process gas composition and flow rates, temperature, pressure, plasma conditions such as RF power levels and the low frequency RF frequency, cooling gas pressure, and chamber wall temperature. 
     The computer program is designed or configured in many different ways. For example, various chamber component subroutines or control objects are written to control operation of components of the plasma chamber  124  ( FIG. 1B ) to carry out the process conditions. Examples of programs or sections of programs for this purpose include substrate positioning code, process gas control code, pressure control code, heater control code, and plasma control code. 
     A substrate positioning program includes a program code for controlling chamber components that are used to load a substrate onto a pedestal or chuck and to control spacing between the substrate and other parts of the plasma chamber  124  such as a gas inlet and/or target. A process gas control program includes a program code for controlling gas composition and flow rates and optionally for flowing gas into the plasma chamber  124  prior to deposition in order to stabilize the pressure in the plasma chamber  124 . A filter monitoring program includes a program code that compares measured differential(s) to predetermined value(s) and/or code for switching paths. A pressure control program includes a program code for controlling pressure in the plasma chamber  124  by regulating, e.g., a throttle valve in an exhaust system of the plasma chamber  124 . A heater control program includes a program code for controlling a current to heater elements for heating one or more process gases in a gas line, for heating the substrate, and/or other portions of the system. For example, the heater control program controls delivery of a heat transfer gas, such as, e.g., helium, etc., to the wafer chuck. 
     Examples of sensors that may be monitored during a process include, but are not limited to, mass flow control modules, pressure sensors such as the pressure manometers  910 , and thermocouples located in delivery system, the pedestal or chuck (e.g. the temperature sensors  914 ). Appropriately programmed feedback and control algorithms are used with data from these sensors to maintain desired process conditions. The foregoing describes implementation of embodiments of the invention in a single or multi-chamber semiconductor processing tool. 
     In one embodiment, functions described herein as being performed by a controller are performed by a processor of the controller. 
     In an embodiment, functions described herein as being performed by a controller are performed by multiple controllers, e.g., are distributed between multiple controllers. 
     Embodiments, described herein, may be practiced with various computer system configurations including hand-held hardware units, microprocessor systems, microprocessor-based or programmable consumer electronics, minicomputers, mainframe computers and the like. The embodiments, described herein, can also be practiced in distributed computing environments where tasks are performed by remote processing hardware units that are linked through a computer network. 
     In some embodiments, a controller is part of a system, which may be part of the above-described examples. The system includes semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform or platforms for processing, and/or specific processing components (a wafer pedestal, a gas flow system, etc.). The system is integrated with electronics for controlling its operation before, during, and after processing of a semiconductor wafer or substrate. The electronics is referred to as the “controller,” which may control various components or subparts of the system. The controller, depending on processing requirements and/or a type of the system, is programmed to control any process disclosed herein, including a delivery of process gases, temperature settings (e.g., heating and/or cooling), pressure settings, vacuum settings, power settings, RF generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and/or load locks connected to or interfaced with the system. 
     Broadly speaking, in a variety of embodiments, the controller is defined as electronics having various integrated circuits, logic, memory, and/or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits include chips in the form of firmware that store program instructions, digital DSPs, chips defined as ASICs, PLDs, one or more microprocessors, or microcontrollers that execute program instructions (e.g., software). The program instructions are instructions communicated to the controller in the form of various individual settings (or program files), defining operational parameters for carrying out a process on or for a semiconductor wafer. The operational parameters are, in some embodiments, a part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and/or dies of a wafer. 
     The controller, in some embodiments, is a part of or coupled to a computer that is integrated with, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller is in a “cloud” or all or a part of a fab host computer system, which allows for remote access for wafer processing. The controller enables remote access to the system to monitor current progress of fabrication operations, examines a history of past fabrication operations, examines trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. 
     In some embodiments, a remote computer (e.g. a server) provides process recipes to the system over a computer network, which includes a local network or the Internet. The remote computer includes a user interface that enables entry or programming of parameters and/or settings, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of settings for processing a wafer. It should be understood that the settings are specific to a type of process to be performed on a wafer and a type of tool that the controller interfaces with or controls. Thus as described above, the controller is distributed, such as by including one or more discrete controllers that are networked together and working towards a common purpose, such as the fulfilling processes described herein. An example of a distributed controller for such purposes includes one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at a platform level or as part of a remote computer) that combine to control a process in a chamber. 
     Without limitation, in various embodiments, the system includes a plasma etch chamber, a deposition chamber, a spin-rinse chamber, a metal plating chamber, a clean chamber, a bevel edge etch chamber, a physical vapor deposition (PVD) chamber, a CVD chamber, an atomic layer deposition (ALD) chamber, an atomic layer etch (ALE) chamber, an ion implantation chamber, a track chamber, and any other semiconductor processing chamber that is associated or used in fabrication and/or manufacturing of semiconductor wafers. 
     It is further noted that although the above-described operations are described with reference to a parallel plate plasma chamber, e.g., a capacitively coupled plasma chamber, etc., in some embodiments, the above-described operations apply to other types of plasma chambers, e.g., a plasma chamber including an inductively coupled plasma (ICP) reactor, a transformer coupled plasma (TCP) reactor, conductor tools, dielectric tools, a plasma chamber including an electron cyclotron resonance (ECR) reactor, etc. For example, the x MHz RF generator, the y MHz RF generator, and the z MHz RF generator are coupled via an impedance matching network to an inductor within the ICP plasma chamber. 
     As noted above, depending on a process operation to be performed by the tool, the controller communicates with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and/or load ports in a semiconductor manufacturing factory. 
     With the above embodiments in mind, it should be understood that some of the embodiments employ various computer-implemented operations involving data stored in computer systems. These computer-implemented operations are those that manipulate physic al quantities. 
     Some of the embodiments also relate to a hardware unit or an apparatus for performing these operations. The apparatus is specially constructed for a special purpose computer. When defined as a special purpose computer, the computer performs other processing, program execution or routines that are not part of the special purpose, while still being capable of operating for the special purpose. 
     In some embodiments, the operations, described herein, are performed by a computer selectively activated, or are configured by one or more computer programs stored in a computer memory, or are obtained over a computer network. When data is obtained over the computer network, the data may be processed by other computers on the computer network, e.g., a cloud of computing resources. 
     One or more embodiments, described herein, can also be fabricated as computer-readable code on a non-transitory computer-readable medium. The non-transitory computer-readable medium is any data storage hardware unit, e.g., a memory device, etc., that stores data, which is thereafter read by a computer system. Examples of the non-transitory computer-readable medium include hard drives, network attached storage (NAS), ROM, RAM, compact disc-ROMs (CD-ROMs), CD-recordables (CD-Rs), CD-rewritables (CD-RWs), magnetic tapes and other optical and non-optical data storage hardware units. In some embodiments, the non-transitory computer-readable medium includes a computer-readable tangible medium distributed over a network-coupled computer system so that the computer-readable code is stored and executed in a distributed fashion. 
     Although some method operations, described above, were presented in a specific order, it should be understood that in various embodiments, other housekeeping operations are performed in between the method operations, or the method operations are adjusted so that they occur at slightly different times, or are distributed in a system which allows the occurrence of the method operations at various intervals, or are performed in a different order than that described above. 
     It should further be noted that in an embodiment, one or more features from any embodiment described above are combined with one or more features of any other embodiment without departing from a scope described in various embodiments described in the present disclosure. 
     Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications can be practiced within the scope of appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the embodiments are not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.