Abstract:
A vaporization system for liquid precursor includes a bubbler portion configured to store liquid precursor and to supply carrier gas into the liquid precursor to vaporize the liquid precursor to generate vaporized precursor. A baffle portion is arranged in fluid communication with the bubbler portion and includes N heated baffles, where N is an integer greater than or equal to one. The vaporized precursor generated by the bubbler portion passes through the N heated baffles before flowing to a substrate processing system.

Description:
FIELD 
       [0001]    The present disclosure relates to substrate processing systems and more particularly to systems and methods for bulk vaporization of precursor in substrate processing systems. 
       BACKGROUND 
       [0002]    The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. 
         [0003]    Substrate processing systems are used to deposit and/or etch film on a substrate such as a semiconductor wafer. For example, the substrate processing system may perform chemical vapor deposition (CVD), plasma-enhanced (PE) CVD, atomic layer deposition (ALD), PEALD, etc. Deposition or etching may be performed by supplying a gas mixture including one or more reactants to a processing chamber. 
         [0004]    To use liquid precursors as reactants in CVD and/or ALD type processes, the liquid precursor is initially vaporized and then transported to a surface of the substrate. The vaporized precursor should not contain any liquid droplets and should have a uniform concentration and accurate dose. Two basic methods are commonly used for vaporizing precursor. For example, a bubbler bubbles a carrier gas through liquid precursor usually at an elevated temperature. The liquid precursor evaporates and is carried away with the carrier gas. However, the bubbler provides a variable exposure surface of the carrier gas to the liquid precursor depending on flow and a liquid level in the bath, which causes variable vapor concentrations. The act of bubbling can also cause droplets and/or foam to form and may cause liquid to be transported by the vaporized precursor to the surface of the substrate. 
         [0005]    Alternately, an evaporator may be used. In the evaporator, a small amount of liquid precursor flows onto a heated surface. The liquid precursor evaporates and is carried away via a pressure differential or using a carrier gas. However, the evaporator feeds liquid from a bulk source in very small amounts. The low flow rate is difficult to meter and deliver accurately. A liquid delivery system typically includes a liquid flow controller and a capillary tube. The liquid delivery system is subject to blockage and bubbles forming in the liquid, which also causes the vapor delivery concentration to vary. 
       SUMMARY 
       [0006]    A vaporization system for liquid precursor includes a bubbler portion configured to store liquid precursor and to supply carrier gas into the liquid precursor to vaporize the liquid precursor to generate vaporized precursor. A baffle portion is arranged in fluid communication with the bubbler portion and includes N heated baffles, where N is an integer greater than or equal to one. The vaporized precursor generated by the bubbler portion passes through the N heated baffles before flowing to a substrate processing system. 
         [0007]    In other features, N is greater than one and each of the N heated baffles comprises a temperature sensor and a heater. A controller is configured to control a temperature of each of the N heated baffles. The controller is configured to control a temperature of the bubbler portion. 
         [0008]    In other features, the controller is configured to control the temperatures of each of the N heated baffles such that a first one of the N heated baffles has a first temperature that is less than a second temperature of a second one of the N heated baffles arranged immediately adjacent to the first one of the N heated baffles. The second temperature is less than a third temperature of a third one of the N heated baffles arranged immediately adjacent to the second one of the N heated baffles. 
         [0009]    In other features, a porous medium is arranged adjacent to a bottom portion of the body to define a cavity. The carrier gas is delivered into the cavity between the porous medium and the bottom portion. A bracket secures the porous medium in a spaced relationship with the bottom portion of the body to define the cavity. 
         [0010]    In other features, a first one of the N heated baffles comprises a baffle body and a first pattern of bores through the baffle body. A second one of the N heated baffles is arranged adjacent to the first one of the N heated baffles and comprises a baffle body and a second pattern of bores through the baffle body. The first pattern of bores does not align with the second pattern of bores. 
         [0011]    In other features, the first one of the N heated baffles further comprises first and second flanges that extend axially outwardly from the baffle body. The first one of the N heated baffles further comprises a groove that is arranged around a periphery of the baffle body and that is configured to receive a heater coil. 
         [0012]    In other features, the first one of the N heated baffles further comprises a bore that is arranged at a center of the body and that is configured to receive a conduit for the carrier gas. 
         [0013]    A method for vaporizing liquid precursor includes supplying liquid precursor to a bubbler portion; supplying carrier gas into the liquid precursor to vaporize the liquid precursor and to generate vaporized precursor; arranging a baffle portion including N heated baffles in fluid communication with the bubbler portion to receive the vaporized precursor, wherein N is an integer greater than or equal to one; and passing the vaporized precursor generated by the bubbler portion through the N heated baffles before flowing the vaporized precursor to a substrate processing system. 
         [0014]    In other features, N is greater than one and the method further comprises sensing a temperature of each of the N heated baffles. The method includes selectively heating each of the N heated baffles to control the temperature based on the sensed temperature. 
         [0015]    In other features, the method includes controlling the temperatures of each of the N heated baffles such that a first one of the N heated baffles has a first temperature that is less than a second temperature of a second one of the N heated baffles arranged immediately adjacent to the first one of the N heated baffles. The second temperature is less than a third temperature of a third one of the N heated baffles arranged immediately adjacent to the second one of the N heated baffles. 
         [0016]    In other features, the method includes arranging a porous medium adjacent to a bottom portion of the body and delivering the carrier gas between the porous medium and the bottom portion. The method includes securing the porous medium in a spaced relationship with the bottom portion of the body. 
         [0017]    In other features, a first one of the N heated baffles comprises a baffle body and a first pattern of bores through the baffle body. In other features, a second one of the N heated baffles is arranged adjacent to the first one of the N heated baffles and comprises a baffle body and a second pattern of bores through the baffle body. 
         [0018]    In other features, the method includes misaligning the first pattern of bores though the baffle body of the first one of the N heated baffles relative the second pattern of bores though the baffle body of the first one of the N heated baffles. The method includes providing first and second flanges that extend axially outwardly from the baffle body of the first one of the N heated baffles. 
         [0019]    In other features, the method includes providing a groove arranged around a periphery of the baffle body of the first one of the N heated baffles and arranging a heater coil in the groove. 
         [0020]    In other features, the method includes providing a bore at center of the baffle body of the first one of the N heated baffles and passing a conduit to supply the carrier gas in the bore. 
         [0021]    A vaporization system for liquid precursor includes a bubbler portion comprising a body to store liquid precursor and a conduit to supply carrier gas into the liquid precursor to vaporize the liquid precursor to generate vaporized precursor. A baffle portion is arranged in fluid communication with the bubbler portion and includes N heated baffles. The vaporized precursor generated by the bubbler portion passes through the N heated baffles before flowing to a substrate processing system, wherein N is an integer greater than one. Each of the N heated baffles comprises a temperature sensor and a heater. A porous medium is arranged adjacent to a bottom portion of the body. The carrier gas is delivered into a cavity between the porous medium and the bottom portion. 
         [0022]    In other features, a controller is configured to control a temperature of each of the N heated baffles. The controller is configured to control a temperature the body of the bubbler portion. 
         [0023]    In other features, the controller is configured to control the temperatures of each of the N heated baffles such that a first one of the N heated baffles has a first temperature that is less than a second temperature of a second one of the N heated baffles arranged immediately adjacent to the first one of the N heated baffles. In other features, the second temperature is less than a third temperature of a third one of the N heated baffles arranged immediately adjacent to the second one of the N heated baffles. 
         [0024]    In other features, a bracket secures the porous medium in a spaced relationship with the bottom portion of the body. 
         [0025]    In other features, a first one of the N heated baffles comprises a baffle body and a first pattern of bores through the baffle body. A second one of the N heated baffles is arranged adjacent to the first one of the N heated baffles and comprises a baffle body and a second pattern of bores through the baffle body. The first pattern of bores does not align with the second pattern of bores. 
         [0026]    Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0028]      FIG. 1  is a side view of an example bulk vaporization system according to the present disclosure; 
           [0029]      FIG. 2  is a perspective view of the example bulk vaporization system according to the present disclosure; 
           [0030]      FIG. 3  is a plan view of a heater coil according to the present disclosure; 
           [0031]      FIG. 4  is a partial exploded perspective view of the example bulk vaporization system according to the present disclosure; 
           [0032]      FIG. 5A  is a side view of an example heated baffle according to the present disclosure; 
           [0033]      FIG. 5B  is another side cross-sectional view of the example heated baffle according to the present disclosure; 
           [0034]      FIG. 5C  is a side cross-sectional view of the example heated baffle according to the present disclosure; 
           [0035]      FIGS. 5D and 5E  are cross-sectional views showing different portions of the baffle portion of the bulk vaporization system; 
           [0036]      FIG. 6A  is a plan view of an example heated baffle according to the present disclosure; 
           [0037]      FIG. 6B  is a plan view of another example heated baffle according to the present disclosure; 
           [0038]      FIG. 7  is a functional block diagram of an example control system for controlling the bulk vaporization system according to the present disclosure; and 
           [0039]      FIG. 8  illustrates a method for controlling the bulk vaporization system according to the present disclosure. 
       
    
    
       [0040]    In the drawings, reference numbers may be reused to identify similar and/or identical elements. 
       DETAILED DESCRIPTION 
       [0041]    Systems and methods for bulk vaporization of liquid precursor according to the present disclosure include a bubbler portion and a heated baffle portion. In some examples, the bubbler portion includes porous media that is used to distribute the carrier gas into the liquid precursor in a more uniform manner. The porous media allows a large surface area of contact between the liquid and the gas. At some point, the increase of the surface area of contact between the liquid and the gas will not cause increased vapor concentration because the liquid is in equilibrium for the temperature/pressure conditions (or saturated). In some examples, systems and methods for bulk vaporization of liquid precursor according to the present disclosure are designed to operate in the saturated region. The porous media will also create very small bubbles that are much less likely to splash and create a large amount of droplets. 
         [0042]    The heated baffle portion includes one or more heated baffles that evaporate liquid transported by the vaporized precursor. Because the heated baffles are at a higher temperature than the bulk liquid in the bubbler portion, the vapor pressure curve is shifted back into the vapor region from the saturated region where the droplets are forming. In some examples, the systems and methods use multi-stage heated baffles with varying bore sizes and passage aspect ratios. In some examples, the heated baffles are operated at increasing temperature to allow suspended aerosol particles to be completely evaporated before leaving the device. 
         [0043]    Referring now to  FIGS. 1-2 , an example bulk vaporization system  10  includes a bubbler portion  12  and a baffle portion  14 . The bulk vaporization system  10  includes a body  20  that includes sidewalls  21  and a bottom portion  24 , and a lid or top portion  28 . A connection  29  may be arranged to connect the body  20  to the baffle portion  14  and to provide a seal therebetween. The baffle portion  14  includes baffles  30 - 1 ,  30 - 2 , . . . , and  30 -B (collectively baffles  30 ) that are arranged adjacent to one another, where B is an integer greater than or equal to one. The baffles  30  may be arranged between the lid  28  and the connection  29 . 
         [0044]    Liquid precursor is supplied to the body  20  as will be described below. A lower end  42  of a conduit  40  extends through the lid  28  and into a cavity  41 . The carrier gas flows into liquid precursor located in the cavity  41  and then through the porous media  44 . For example only, the porous media  44  may include a plate including spaced bores. The porous media  44  provides a porous separation between the cavity  41  and the rest of the body  20 . For example only, the pore size may be approximately 20 μm. In some examples, the porous media  44  may be made from sintered stainless steel. One or more brackets  46  may be used to maintain a position of the porous media  44  relative to the cavity  41 . 
         [0045]    For example only, the bracket  46  may include an annular plate  45  having bores  47  passing through in an axial direction. The bores  47  may be spaced uniformly around the annular plate  45 . Fasteners  48  such as threaded bolts may be inserted into bores  47  to attach the annular plate to the bottom portion  24 . The annular plate  45  may include a radially inwardly projecting flange  49  located near an upper portion of the annular plate  45 . The radially inwardly projecting flange  49  holds the porous media  44  in place above the cavity  41 . 
         [0046]    In some examples, a temperature of the bulk vaporization system  10  may be controlled. For example, the bottom portion may include a heater coil and connector assembly (not shown) to supply heat to the bottom portion  24 . A thermocouple or temperature sensor  50  may be provided to monitor a temperature of the bottom portion  24 . Likewise, the body  20  may be heated in a similar manner. 
         [0047]    In  FIG. 2 , each of the baffles  30  may also include a corresponding heater coil and connector assembly  32 - 1 ,  32 - 2 , . . . , and  32 -B (collectively heater coil and connector assemblies  32 ). Thermocouple connector assemblies  54 - 1 ,  54 - 2 , . . . , and  54 -B (collectively thermocouple connector assemblies  54 ) and  56  may also be provided to monitor the temperature of each of the corresponding baffles  30  and the lid  28 , respectively. Heater coils  62  may be arranged in grooves formed in the baffles  30  and/or other components such as the lid  28  or bottom portion  24 . In  FIG. 3 , an example of the heater coil  62  is shown. 
         [0048]    Referring back to  FIGS. 1 and 2 , various passages through the lid  28  are shown. A level sensor  70  may be arranged as shown to sense a level of liquid precursor in the body  20 . Any suitable type of level sensor  70  may be used. For example only, an ultrasonic level sensor using crystals arranged at L levels may be used, where L is an integer greater than one. For example, L may be set to 4 and liquid precursor may be filled and maintained during normal operation to a level between the 2 nd  and 3 rd  level. An alarm or other signal may be generated if the level of the liquid precursor rises above the 3 rd  level or reaches the 4 th  level. 
         [0049]    In some examples, a gas valve  72  may be arranged centrally relative to the lid  28  and gas may be supplied to the gas valve via a connector  78 . The gas may flow through a passage  79  ( FIG. 1 ) in the lid  28  and into an inlet of the gas valve  72 . The passage  79  in the lid  28  pre-heats the gas as the gas enters the bulk vaporization system  10 . 
         [0050]    One or more additional valves may be connected to the connector  78  to control flow into the passage  79 . The gas valve  72  includes an inlet that communicates with the passage  79  and an outlet that communicates with the body  20 . A connector  76  may be used to deliver and/or remove liquid precursor to/from the body  20 . One or more additional valves may be connected to the connector  76  to control flow through the connector  76 . 
         [0051]    A bore  80  in  FIG. 2  receives a pressure sensor  81  or manometer to measure pressure in the body  20 . In some examples, the pressure sensor  81  may be a capacitance-type manometer including a diaphragm, although other types of pressure sensors can be used. A plate is attached to the diaphragm. As the diaphragm moves under pressure, the plate moves relative to a stationary plate and the capacitance changes. The bore  80  extends through the lid  28  to allow the pressure sensor  81  to measure the pressure. In some examples, the pressure measurement area is in a region between an uppermost one of the baffle  30  and the lid  28  of the bulk vaporization system  10 . However, the bore  80  may also extend through the baffles  30  into the body  20  if the pressure is to be measured in the body  20 . 
         [0052]    In  FIG. 4 , the connection  29  is shown to include a bottom seal portion  84  connected to the body  20  and an upper seal portion  86  connected to the baffle portion  14 . The bottom seal portion  84  defines a channel  90  to receive a seal  92  that mates with a corresponding flat surface provided by the upper seal portion  86 . Using the channel  90  and the flat surface provided by the upper seal portion  86  controls the compression of the seal  92 . 
         [0053]    In some examples, the seal  92  may be “C”-shaped, “V”-shaped, “O”-shaped “W”-shaped or have another cross-section. The seal  92  can also be eliminated by welding the assembly closed. 
         [0054]    Fasteners may be provided to attach the bottom seal portion  84  to the upper seal portion  86 . For example only, the fasteners may include threaded bolts or screws  94  that are inserted through the bottom seal portion  84  and that are received by corresponding bores  96  formed in the upper seal portion  86 . Nuts or other fasteners may be connected to the bolts or screws  94 . A second conduit  98  may be provided to supply or remove the liquid precursor into the body  20 . The second conduit  98  may have one end connected to the connector  76 . 
         [0055]    In use, liquid precursor is supplied into the body  20  via the second conduit  98 . Carrier gas is supplied via the conduit  40  into the cavity  41 . The carrier gas creates bubbles that are further dispersed by the porous media  44  to provide more effective bubbling of the liquid precursor. Vaporization of the liquid precursor occurs and the vaporized precursor flows through the baffle portion  14  and is then supplied to one or more substrate processing systems. In some examples, temperatures of the baffles  30 - 1 ,  30 - 2  and  30 -B are set to the same temperature, successively increasing temperatures, successively decreasing temperatures, or other temperature values. 
         [0056]    Referring now to  FIGS. 5A-5C , an example baffle  30  is shown. In  FIG. 5A , the baffle  30  is shown to include a body  100 . In some examples, the body  100  is circular shaped. For example, the body  100  has a diameter that is approximately equal to a diameter of the body  20 . The body  100  defines a channel  104  on an outer surface or circumference thereof for receiving the heater coil  62 . The body also defines an upper flange  110  and a lower flange  112 . The upper and lower flanges  110  and  112  include projections that extend around an outer periphery of the body  100 . A notch  116  in the body  100  provides a location for connecting a thermocouple. 
         [0057]    In  FIG. 5B , the baffle  30  defines a plurality of bores  130  that extend from a lower baffle surface  132  to an upper baffle surface  134 . As can be seen in  FIGS. 5B and 5C , the upper and lower flanges  110  and  112  are located around the upper and lower baffle surfaces  134  and  132 . A bore  120  may be provided to allow the conduit  40  pass through the baffle plate. 
         [0058]    In some examples, the bores  130  are arranged in a regular or irregular pattern. The bores may have the same size diameter or different size diameters. The bores may have the same aspect ratio or different aspect ratios. While the bores are shown arranged along radial lines and pass through the body in the same direction, the direction and alignment of the bores may be varied. The cross-section shown in  FIG. 5B  is located along one of the radial lines that includes the bores  130 . In  FIG. 5C , however, the cross-section is shown spaced from one of the radial lines that includes the bores. 
         [0059]    Referring now to  FIGS. 5D and 5E , cross-sectional views of the baffle portion  14  of the bulk vaporization system  10  are shown. In  FIG. 5D , the lower flange  112  of the baffle  30 - 1  is in contact with an axial flange  136  of the upper seal portion  86 . The upper flange  110  of the baffle  30 - 1  is in contact with the lower flange  112  of the baffle  30 - 2 . In other words, the upper and lower flanges  110  and  112  of adjacent baffles  30  may be welded or otherwise connected together to provide a vacuum seal. The limited contact area and spacing provided between the baffles provides thermal resistance to allow temperature differences to be created and maintained between the baffles. In  FIG. 5E , a bore  71  associated with the level sensor  70  is shown extending through the lid  28  and the baffles  30  to a location above the upper seal portion  86 . 
         [0060]    Referring now to  FIGS. 6A-6B , examples of the baffles are shown. In  FIG. 6A , the upper baffle surface  134  of a body  100 - 1  is shown. The body  100 - 1  includes a first pattern  114 - 1  of the bores  130 . In this example, the first pattern  114 - 1  includes bores that are arranged in a regular pattern along radial lines of the body  100 - 1 . The radial lines of bores are spaced at predetermined intervals or irregular intervals. For example, the radial lines of bores are spaced at 30° intervals. The body  100 - 1  also defines first and second bores  140  and  142 . The bore  140  may be aligned with the bore  80  in the lid  28 . The bore  142  may receive the second conduit  98 . 
         [0061]    In  FIG. 6B , the upper baffle surface  134  of another body  100 - 2  is shown. The body  100 - 2  includes a second pattern  114 - 2  of the bores  130 . The second pattern  114 - 2  of the bores  130  also includes bores that are arranged in a regular pattern along radial lines of the body  100 - 2 . The radial lines of bores are also spaced at predetermined intervals. However, the second pattern  114 - 2  of bores  130  are rotated relative to the first pattern  114 - 1  of bores on the body  100 - 1  in  FIG. 6A . In this example, the bores in  FIG. 6B  are rotated approximately 15° relative to the bores shown in the body  100 - 1 . Some of the vapor flows through the baffles  30  without direct contact as it is a gas and many molecules will be entrained in the gas flow and will not contact the heated baffle surface. However, the convoluted path imparts direction changes in the gas flow that may have droplets entrained. The direction change uses the inertia of the droplets to cause the droplets to impinge upon the heated baffle surface. As a result, the droplets have a much lower probability of exiting the heated baffles. 
         [0062]    Referring now to  FIG. 7 , a control system  300  for controlling the bulk vaporization system is shown. The control system  300  includes a controller  302 . The controller  302  controls a valve  304  that supplies carrier gas. The controller  302  also controls operation of valves  306 - 1 ,  306 - 2 , . . . , and  306 -V (collectively valves  306 ), where V is an integer greater than or equal to one. The valves  306  supply vaporized precursor to corresponding substrate processing systems. 
         [0063]    The controller  302  controls heating of baffles  308 - 1 ,  308 - 2 , . . . , and  308 -B (collectively baffles  308 ). The controller  302  receives a temperature signal from a temperature sensor  312  and supplies current to a heater coil  310  for each of the baffles  308 . The controller  302  communicates with a heater  322  and temperature sensor  324  associated with the body  320 . The controller  302  communicates with a heater  332  and temperature sensors  334  associated with a bottom portion  330 . 
         [0064]    The controller  302  also communicates with a heater  342  and temperature sensors  344  associated with a lid  340 . The controller  302  receives a level of liquid precursor from a level sensor  350  and selectively controls a valve  352  to supply liquid precursor to the body. The controller  302  also receives pressure signals from pressure sensors  360  and  362 , which measure system pressures. For example, one of the pressure sensors may sense pressure in the body region above the liquid and one of the pressure sensors may sense pressure in the exit region above the heated baffles. The use of two pressure sensors may help to identify clogging of the heated baffles. For example, clogging may be identified when a pressure differential exceeds a predetermined pressure differential. 
         [0065]    While each of the baffles, body, bottom portion and/or lid are shown with individual temperature sensing and control, any two or more of these structures can be controlled as one zone. For example only, the body and the bottom portion may be controlled with a single temperature sensor and heaters connected in series as one zone. 
         [0066]    Referring now to  FIG. 8 , a method  400  for controlling the bulk vaporization system is shown. At  404 , control determines whether there is a request for vaporized precursor. At  410 , control senses a temperature of the baffles, body, bottom portion and/or lid. At  414 , control determines whether the temperatures of the baffles, body, bottom surface and/or lid are correct. If not, control adjusts one or more temperatures based on the temperature feedback at  416 . If the temperatures are correct at  414 , control turns on the carrier gas at  422 . Control may wait a predetermined period to allow vaporized precursor to build in the system. At  426 , control opens selected valves as needed to deliver vaporized precursor to one or more processes. At  430 , control determines whether the vaporized precursor request has ended. If not, control returns to  426 . Otherwise, control closes one or more of the valves to the processes at  434 . At  438 , control optionally turns off the carrier gas or heaters as well. As can be appreciated, control may also monitor the level of liquid precursor in the body and selectively operate a valve to fill the body with the liquid precursor as needed. 
         [0067]    In some examples, an output of the bulk vaporization system  10  is fed to four processing chambers. An output of the bulk vaporization system  10  is fed to charge volumes associated with each processing chamber. Pressure ramps up to a predetermined value and then a charge is delivered from the charge volumes to each processing chamber. Then, pressure ramps back up in each charge volume. 
         [0068]    The systems and methods described herein produce a flow of uniform concentration of vaporized precursor from a bulk quantity of material. Since the systems and methods operate in a saturation region for the given material, flow increases, decreases, starts and stops provide relatively uniform vapor concentration. The systems and methods described herein also reduced defects and provide improved control of the concentration of the vaporized precursor. 
         [0069]    The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A or B or C), using a non-exclusive logical OR. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. 
         [0070]    In this application, including the definitions below, the term controller may be replaced with the term circuit. The term controller may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog/digital discrete circuit; a digital, analog, or mixed analog/digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor (shared, dedicated, or group) that executes code; memory (shared, dedicated, or group) that stores code executed by a processor; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip. 
         [0071]    The term code, as used above, may include software, firmware, and/or microcode, and may refer to programs, routines, functions, classes, and/or objects. The term shared processor encompasses a single processor that executes some or all code from multiple controllers. The term group processor encompasses a processor that, in combination with additional processors, executes some or all code from one or more controllers. The term shared memory encompasses a single memory that stores some or all code from multiple controllers. The term group memory encompasses a memory that, in combination with additional memories, stores some or all code from one or more controllers. The term memory may be a subset of the term computer-readable medium. The term computer-readable medium does not encompass transitory electrical and electromagnetic signals propagating through a medium, and may therefore be considered tangible and non-transitory. Non-limiting examples of a non-transitory tangible computer readable medium include nonvolatile memory, volatile memory, magnetic storage, and optical storage. 
         [0072]    The apparatuses and methods described in this application may be partially or fully implemented by one or more computer programs executed by one or more processors. The computer programs include processor-executable instructions that are stored on at least one non-transitory tangible computer readable medium. The computer programs may also include and/or rely on stored data.