Patent Publication Number: US-2022213595-A1

Title: Oscillating flow boundary layers in apparatus, methods, and systems for processing substrates

Description:
BACKGROUND 
     Field 
     Aspects of the present disclosure generally relate to oscillating a boundary layer of a flow of process gas in methods and systems for processing substrates. In one aspect, one or more of a pressure, a gas flow rate, and/or a height of a substrate are oscillated during processing to induce boundary layer oscillation. 
     Description of the Related Art 
     During substrate processing operations, process gases can flow over substrates. A boundary layer for the flow of gas can exist adjacent to the surface of the substrate. The slower flow of gases in the boundary layer can limit chemical reactions of reactants and can limit flow of reactants to the substrate, which can hinder processing operations and can hinder conformality of layers formed upon the substrates. 
     Therefore, there is a need for improved apparatus, systems, and methods that reduce effects of boundary layers in flows of process gases to facilitate one or more of increased throughput, reduced downtime, and increased conformality. 
     SUMMARY 
     Aspects of the present disclosure generally relate to oscillating a boundary layer of a flow of process gas in methods and systems for processing substrates. In one aspect, one or more of a pressure, a gas flow rate, and/or a height of a substrate are oscillated during processing. 
     In one implementation, a method of processing a substrate includes conducting a processing operation on the substrate in an interior volume of a processing chamber. The conducting the processing operation on the substrate includes moving a flow of one or more process gases over a surface of the substrate. The method also includes oscillating a boundary layer of the flow of one or more process gases while the flow of one or more process gases moves over the surface of the substrate. The oscillating the boundary layer includes one or more of: oscillating a pressure of the interior volume, oscillating an amount of the one or more process gases introduced into the interior volume, oscillating a height of the substrate in the interior volume, oscillating a distance between a ceiling of the interior volume and the surface of the substrate, or oscillating a distance between a gas injection assembly and the surface of the substrate. 
     In one implementation, a non-transitory computer-readable medium includes instructions that, when executed, cause a system to conduct a processing operation on a substrate in an interior volume of a processing chamber. The conducting the processing operation on the substrate includes moving a flow of one or more process gases over a surface of the substrate. The instructions, when executed, also cause the system to oscillate a boundary layer of the flow of one or more process gases while the flow of one or more process gases moves over the surface of the substrate. The oscillating the boundary layer includes one or more of: oscillating a pressure of the interior volume, oscillating an amount of the one or more process gases introduced into the interior volume, oscillating a height of the substrate in the interior volume, oscillating a distance between a ceiling of the interior volume and the surface of the substrate, or oscillating a distance between a gas injection assembly and the surface of the substrate. 
     In one implementation, a system for processing substrates includes a processing chamber having an interior volume, a substrate support disposed in the interior volume, and a gas inlet fluidly coupled to an inlet path and a gas source to introduce one or more process gases into the interior volume. The system also includes a gas outlet fluidly coupled to an outlet path and a vacuum pump to exhaust the one or more process gases from the interior volume. The system also includes a rotatable valve disposed upstream of the vacuum pump along the outlet path. The rotatable valve includes a valve housing, and a flapper that is freely rotatable relative to the valve housing. The system also includes a pump motor coupled to the rotatable valve to rotate the flapper. The system also includes a pressure control valve disposed between the rotatable valve and the vacuum pump along the outlet path. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of scope, as the disclosure may admit to other equally effective embodiments. 
         FIG. 1A  is a schematic partial sectional view of a system for processing substrates, according to one implementation. 
         FIG. 1B  is an enlarged partial schematic view of the system shown in  FIG. 1A  during the processing operation, according to one implementation. 
         FIG. 1C  is a schematic graphical illustration of an oscillation frequency, according to one implementation. 
         FIG. 2A  is a schematic partial top view of the system shown in  FIG. 1A , according to one implementation. 
         FIG. 2B  is a schematic partial top view of the system shown in  FIG. 1A , according to one implementation. 
         FIG. 3  is a schematic view of a method of processing a substrate, according to one implementation. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. 
     DETAILED DESCRIPTION 
     Aspects of the present disclosure generally relate to oscillating a boundary layer of a flow of process gas in methods and systems for processing substrates. In one aspect, one or more of a pressure, a gas flow rate, and/or a height of a substrate are oscillated during processing. 
       FIG. 1A  is a schematic partial sectional view of a system  101  for processing substrates, according to one implementation. The system  101  includes a processing chamber  110 . The processing chamber  110  includes a chamber body  185  having a first portion  184  forming a sidewall of the chamber body  185 , a second portion  186  coupled to the first portion and partially defining a floor or base of the chamber body  185 , a window  135  disposed on the first portion  184  of the chamber body  185 , and a lamp assembly  183  disposed on the window  135 . A chamber base  188  is coupled to the chamber body  185  opposite the window  135 . The lamp assembly  183  includes a housing  199  with a plurality of openings  130  formed therein. A plurality of lamps  155  is disposed in the housing  199 , and a single lamp  155  is disposed within a corresponding opening  130 . The lamps  155  are disposed in respective electrical sockets  198  which are concentrically aligned with the corresponding openings  130 . The lamps  155  are coupled to a controller  1002  via a plurality of electrical conduits  116  and the electrical sockets  198 . 
     During operation, a substrate  192  is loaded into the processing chamber  110  through a transfer port, such as a slit valve port. The substrate  192  is positioned on a plurality of lift pins  136 . The lift pins  136  actuate to position the substrate  192  onto a substrate support  191 . The lamps  155  heat the substrate  192  to a desired processing temperature while the substrate support  191  is rotated to rotate the substrate about a central axis during a processing operation. During the processing operation, one or more process gases are flowed into the processing chamber  110  to deposit a new material layer or modify a previously deposited layer on the substrate  192 . After completion of the processing operation, the substrate  192  may undergo one or more additional processing operations within the process chamber  110  or the substrate  192  may be removed from the processing chamber  110 . After processing of the substrate  192  in the processing chamber  110 , the plurality of lift pins  136  are actuated to raise the substrate  192  from the substrate support  191 . The substrate  192  is then removed from the processing chamber  110  through the transfer port. 
     The processing operation conducted in the processing chamber  110  includes one or more of an oxidation operation, a plasma immersion ion implantation operation, an epitaxial deposition operation, a chemical vapor deposition (CVD) operation, an atomic layer deposition (ALD) operation, an etching operation, or a thermal annealing operation. The processing chamber  110  described is an oxidation chamber. The present disclosure contemplates that aspects of the system  101  and the processing chamber  110  may be used in conjunction with a plasma immersion ion implantation chamber, an epitaxial deposition chamber, a chemical vapor deposition (CVD) chamber, a physical vapor deposition (PVD) chamber, an atomic layer deposition (ALD) chamber, an etching chamber, or a thermal annealing chamber. 
     The lamps  155  emit electromagnetic (EM) radiation that passes through the window  135  and towards the substrate  192  disposed in the processing chamber  110  to heat the substrate  192  to a processing temperature. The window  135  is typically made of a material chemically resistant to the processing environment and able to allow one or more wavelengths of EM radiation emitted by the plurality of lamps  155  to pass through the window  135  without being substantially attenuated. For example, quartz may be used as the window  135  material. Other suitable materials include, but are not limited to, sapphire, ceramic, and glass. 
     The window  135  may be coated with an anti-reflective coating, or suitable filters, on one or both sides of the window  135 . For example, optional ultra-violet (UV) filters can be used to avoid generation of ions and radicals in the chamber or damage to UV-sensitive structures on the substrate  192  if the lamps  155  have significant UV output. As another example, optional notch filters can be used to block narrow band radiation emitted from the lamps  155 . In one embodiment, which can be combined with other embodiments, a filter  139  is disposed on an inside (e.g. process-facing) surface of the window  135 . The filter  139  blocks radiation having wavelengths within a specific range from passing therethrough while allowing radiation having wavelengths outside of the specific range to pass. The filter  139  may be a plurality of alternating layers, such as oxide layers. In one embodiment, which can be combined with other embodiments, the filter  139  includes alternating silicon dioxide layers and titanium dioxide layers. For example, the filter  139  may include a total of 30 to 50 alternating layers, such as 35 to 45 alternating layers, with silicon dioxide layers located at opposite sides (e.g. an outside surface and an inside surface) of the filter  139 . The filter  139  may be coated on an outside surface (e.g. facing the lamp assembly  183 ) of the window  135 , an inside surface (e.g. facing the substrate support  191 ) of the window  135 , or may be embedded within the window  135 . 
     A reflector plate  153  is disposed on the chamber base  188  at a location within the processing chamber  110 . The reflector plate  153  includes a plurality of openings  134  extending therethrough. The plurality of lift pins  136  are at least partially extendable within the processing chamber  110 , and each of the lift pins  136  extends through one of the plurality of openings  134 . The chamber base  188  a plurality of openings  138 . Each of the plurality of openings  138  is aligned with a corresponding opening  134  of the plurality of openings  134  of the reflector plate  153 . Each lift pin  136  is disposed within a receptacle  137  that is coupled to the chamber base  188  of the processing chamber  110  and concentric with the openings  134 ,  138 . The lift pins  136  are magnetically actuated to raise and lower through the openings  134 ,  138 . 
     During operation, the lamps  155  generate EM radiation that is emitted therefrom towards the substrate  192 . A portion of the EM radiation typically passes through the substrate  192 . The intensity of the EM radiation that passes through the substrate  192  is a function of the temperature of the substrate  192  and of the wavelength of the EM radiation. The system  101  can include radiation detectors (such as pyrometers and/or spectrometers) that measure blackbody radiation from the substrate and/or EM radiation emitted by the lamps  155  that has passed through the substrate  192  to measure a temperature of the substrate  192 . An incident radiation detector  180  (such as a spectrometer or pyrometer) is optionally coupled to the housing  199  of the lamp assembly  183 . The incident radiation detector  180  is used to sample the EM radiation emitted by the plurality of lamps  155  at a position before the emitted EM radiation interacts with the substrate  192 . The EM radiation detected by the incident radiation detector  180  can be compared to the EM radiation detected by the radiation detectors to determine the amount of EM radiation that passes through the substrate  192  for substrate temperature measurements. 
     In one embodiment, which can be combined with other embodiments, the lamps  155  are arranged in the housing  199  in a honeycomb array. The lamps  155  may be divided into groups to define multiple heating zones on the substrate  192 . In one embodiment, which can be combined with other embodiments, the heating zones are concentric rings. The radiation detectors may correspond to one of the zones. A temperature or temperature signal determined by operation of the radiation detectors, which may correspond to a defined heating zone, is provided to the controller  1002 . The controller  1002  can individually adjust the power supplied the lamps  155  corresponding to the one or more heating zones to adjust the energy emitted thereto. The temperature profile across the substrate  192  can be adjusted as desired. Additionally, a plurality of detectors  190  can be disposed within the housing  199  (one detector  190  is shown in  FIG. 1 ). The detector  190  is located between adjacent openings  130  and proximate to the window  135 . The detector  190  is line-of-sight exposed to an upper surface  133  of the substrate  192  through the window  135 . The detector  190  is used to determine a temperature of the substrate  192  at the upper surface  133  thereof. The detector  190  is an optical sensor, such as a pyrometer, and receives EM radiation emitted from the upper surface  133  of the substrate  192 . A measured parameter of the EM radiation received by detector  190  from the substrate  192 , such as wavelength or intensity, is used to determine a temperature of the substrate  192 . In one embodiment, which can be combined with other embodiments, the detector  190  is a reflectometer that measures reflectivity of the substrate  192  for temperature measurements. 
     The processing chamber  110  includes an interior volume  102 . A ceiling  103  of the interior volume  102  is defined at least partially by the window  135 , such as the filter  139  of the window  135 . The substrate support  191  is disposed in the interior volume  102 . The processing chamber  110  includes a gas inlet  197  formed in the first portion  184  (e.g., the sidewall) of the chamber body  185 . The present disclosure contemplates that the gas inlet  197  can be formed through the ceiling  103 , such as through the window  135 . The gas inlet  197  is fluidly coupled to a first inlet path  107  and a first gas source  109  to introduce the one or more process gases  111  into the interior volume  102 . During the processing operation, the first gas source  109  is used to introduce the one or more process gases  111  into the interior volume  102  through one or more valves (a supply valve  123  is shown in  FIG. 1 ) disposed along the first inlet path  107 . 
     A motor  124  can be coupled to the window  135  and/or the filter  139  to move at least a portion of the window  135  and/or the filter  139  upwardly and downwardly. Movement of at least the portion of the window  135  and/or filter  139  upwardly and downwardly moves the ceiling  103  upwardly and downwardly to optionally oscillate a distance D 1  between the ceiling  103  of the interior volume  102  and the upper surface  133  of the substrate  192 . Oscillating the ceiling  103  upwardly and downwardly oscillates a volume of the processing region  118 . The present disclosure contemplates that a different upper component, such as a showerhead or a gas distribution plate, may be used in place of the window  135  and the filter  139 . 
     In one embodiment, which can be combined with other embodiments, a diaphragm  181  may be positioned below the window  135  and above the substrate  192  such that the diaphragm  181  defines the ceiling  103  of the interior volume  102 . The diaphragm  181  has a low mass and/or a compressible material such that the diaphragm  181  is movable, such as by the motor  124  and/or by the processing gases  111 ,  131 . The diaphragm  181  is oscillated upwardly and downwardly to oscillate the distance D 1  between the ceiling  103  of the interior volume  102  and the upper surface  133  of the substrate  192 . 
     The processing chamber  110  includes a gas outlet  161  (such as an exhaust port) fluidly coupled to an outlet path  112  and a vacuum pump  1001  to exhaust the one or more process gases  111  from the interior volume  102 . The gas outlet  161  is formed vertically in the second portion  186  of the chamber body  185 . A rotatable valve  182  is disposed upstream of the vacuum pump  1001  along the outlet path  112 . The rotatable valve  182  includes a valve housing  114  and a flapper  115  that is freely rotatable relative to the valve housing  114 . The gas outlet  161  is formed on an opposite side of the substrate support  191  and the substrate  192  relative to the gas inlet  197 . The gas outlet  161  is formed radially outside of the substrate support  191  and the substrate  192 . A pump motor  117  is coupled to the rotatable valve  182  to rotate the flapper  115 . A pressure control valve (PCV)  169  is disposed between the rotatable valve  182  and the vacuum pump  1001  along the outlet path  112 . The PCV  169  is utilized to control and maintain the pressure within the interior volume  102  of the processing chamber  110 . The PCV  169  is selectively opened, closed, or partially opened (e.g., throttled) to change the rate at which the processing gases  111  are exhausted from the processing chamber  110 . 
     A second vacuum pump  119  can optionally be connected to the lamp assembly  183 . The pressure within the lamp assembly  183  is controlled by a valve  121  disposed in a foreline of the second vacuum pump  119 . During the processing operation, the pump motor  117  rotates the flapper  115  in a rotational direction while the one or more process gases  111  are introduced into the interior volume  102 , thereby oscillating a pressure of the interior volume  102 . In one embodiment, which can be combined with other embodiments, the flapper  115  rotates in a single continuous rotational direction. 
     The present disclosure contemplates that the gas outlet  161  can be formed horizontally in the first portion  184  on an opposite side of the substrate support  191  and the substrate  192  relative to the gas inlet  197 . As the one or more processing gases  111  flow from the gas inlet  197  and toward the gas outlet  161 , the one or more processing gases  111  move over the upper surface  133  of the substrate  192 . 
     In one embodiment, which can be combined with other embodiments, the system  101  includes a gas injection assembly  125 . The gas injection assembly  125  includes a linear showerhead  126  extending above the substrate support  191  and the substrate  192 . The linear showerhead  126  includes a longitudinal duct  127  having a central opening  128  extending longitudinally and a plurality of openings  129  formed in a bottom of the longitudinal duct  127 . The longitudinal duct  127  is formed of quartz. The longitudinal duct  127  can have a cross section that is rectangular in shape (as shown in  FIG. 1A ) or circular in shape such that the longitudinal duct  127  is a cylindrical tube. During the processing operation, the gas injection assembly  125  introduces one or more processing gases  131  into the interior volume  102 . The one or more processing gases  131  may flow from the first gas source  109  or a different gas source. The one or more processing gases  131  may have the same gas composition as the one or more processing gases  111 . The gas injection assembly  125  is movable upwardly and downwardly using a motor  132  (shown in  FIG. 2A ) to oscillate a distance D 2  between the gas injection assembly  125  and the upper surface  133  of the substrate  192 . In one embodiment, which can be combined with other embodiments, the distance D 2  is between the upper surface  133  and the bottom of the longitudinal duct  127 . 
     In one embodiment, which can be combined with other embodiments, the one or more process gases  111  and/or the one or more process gases  131  include one or more of Ar, O 2 , He, and/or H 2 O. 
     An annular channel  187  is formed in the chamber body  185 , and a rotor  196  is disposed in the channel  187 . The channel  187  is located adjacent to the second portion  186  of the chamber body  185 . The processing chamber  110  further includes a rotatable support member  189  disposed in the channel  187 . The rotatable support member  189  is supported on and/or coupled to the rotor  196 . The substrate support  191  is supported on the rotatable support member  189 , and a shield  194  is disposed on the second portion  186  of the chamber body  185 . The rotatable support member  189  is fabricated from a material having minimal change in material properties, such as tensile strength or thermal expansion, across a range of temperatures, or resistance to degradation due to exposure to heat. An exemplary material for the rotatable support member  189  is quartz. In one embodiment, which can be combined with other embodiments, the rotatable support member  189  is cylindrical, such as a cylindrical sleeve. In one embodiment, which can be combined with other embodiments, the substrate support  191  is an annular edge ring on which an outer periphery, such as an outer circumferential edge, of the substrate  192  is supported during the processing operation conducted on the substrate  192 . The rotatable support member  189  and the substrate support  191  are at least a part of a substrate support assembly. 
     The channel  187  has an outer wall  150  and an inner wall  152 . A lower first portion  154  of the outer wall  150  has a first radius and an upper second portion  156  of the outer wall  150  has a second radius greater than the first radius. A third portion  158  of the outer wall  150  connecting the first portion  154  to the second portion  156  has a cross-sectional profile that extends linearly from the first portion  154  to the second portion  156 , forming a slanted surface that faces toward the substrate support  191 . The shield  194  has a first portion  160  that rests on the second portion  186  of the chamber body  185  and a second portion  162  that extends into the channel  187  along the second portion  156  of the outer wall  150 . The first portion  160  of the shield  194  contacts the second portion  186  of the chamber body  185 , and the second portion  162  of the shield  194  contacts the second portion  156  of the outer wall  150 . The shield  194  extends partially over the channel  187 . In one embodiment, which can be combined with other embodiments, the shield  194  is a rotor cover. The shield  194  is an annular ring. The shield  194  may have one or more gaps extending in a radial direction from a center thereof. The shield  194  can be fabricated from a ceramic material, such as alumina. The shield  194  further includes a first surface  193  facing the window  135 . The first surface  193  is substantially flat, and is oriented away from a portion of a processing region  118  of the processing chamber  110  located above the substrate  192 , so radiant energy is not reflected therefrom towards the substrate  192 . In one embodiment, which can be combined with other embodiments, the first surface  193  of the shield  194  is substantially parallel to the window  135 . In one embodiment, which can be combined with other embodiments, the first surface  193  is annular. The processing region  118  of the interior volume  102  is between the substrate  192  and the ceiling  103 . 
     The substrate  192  is disposed on the substrate support  191  during the processing operation. A stator  195  is located external to the chamber body  185  in a position axially aligned with the rotor  196 . The rotor  196  is disposed in the interior volume  102  and inwardly of the stator  195 . The substrate support  191  is supported on the rotor  196  through the rotatable support member  189 , and the substrate support  191  is movable upwardly and downwardly using the rotor  196  and the stator  195 . 
     In one embodiment, which can be combined with other embodiments, the stator  195  is a magnetic stator, and the rotor  196  is a magnetic rotor. The stator  195  has a plurality of electric coils therein which circumscribe the channel  187 . During operation, the stator  195  applies a sequence of currents to the coils at defined intervals. The currents within the coils create a series of magnetic fields which are coupled to a magnetic portion of the rotor  196 , such as a magnet disposed therein, through the outer wall  150 . The currents are applied to the coils in a sequence so that the magnetic fields formed therein attract the magnetic portion of the rotor  196  and bias the rotor  196  to rotate about an axis which in turn rotates the rotatable support member  189  magnetically coupled thereto, the substrate support  191 , and the substrate  192 . The currents applied to the coils of the stator  195  can also be used to move the rotor  196  upwardly and downwardly within the interior volume. During the processing operation, the currents are pulsed to oscillate the rotor  196 , and hence oscillate the substrate support  191  and the substrate  192 , upwardly and downwardly within the interior volume  102 . The currents are pulsed to oscillate a height H 1  of the substrate support  191  in the interior volume  102 . In one embodiment, which can be combined with other embodiments, the height H 1  is between the substrate support  191  and the chamber base  188 . In one embodiment, which can be combined with other embodiments, the height H 1  is between the substrate support  191  and the second portion  186 . Oscillating the height H 1  oscillates a height of the substrate  192  disposed on the substrate support  191 . 
     During the processing operation, a temperature of the substrate support  191  may raise more than a temperature of the substrate  192 , thereby raising a temperature of an edge of the substrate  192  relative to a center of the substrate  192 . A cooling member  151  can be disposed on the chamber base  188  in proximity to the substrate support  191  to cool the substrate support  191  using convection. The cooling member  151  convects heat from the substrate support  191  and the substrate  192  when disposed thereon. The chamber base  188  includes a first surface  120  and a second surface  122  opposite the first surface  120 . As shown in  FIG. 1 , the cooling member  151  is in direct contact with the first surface  120  of the chamber base  188 . 
     A thickness of the substrate support  191  may be selected to provide a desired thermal mass. The substrate support  191  can act as a heat sink, which mitigates overheating at the edge of the substrate  192 . In one embodiment, which can be combined with other embodiments, a feature  144 , such as a fin, is formed on the substrate support  191  to provide thermal mass. The feature  144  may be continuous, for example cylindrical, or discontinuous, for example a plurality of discrete fins. 
     The feature  144  may be formed on a surface of the substrate support  191  that is facing the channel  187  when the substrate support  191  is installed in the chamber  100 , and may extend into the channel  187 , as shown in  FIG. 1 . In one embodiment, which can be combined with other embodiments, the feature  144  is formed on a surface of the substrate support  191  that is facing the window  135 . In one embodiment, which can be combined with other embodiments, a combination of one or more features  144  facing the channel  187  and one or more features  144  facing the window  135  may be used. As depicted in  FIG. 1 , the feature  144  may be substantially perpendicular to a major surface of the substrate support  191 . In one embodiment, which can be combined with other embodiments, the feature  144  may extend obliquely from the major surface of the substrate support  191 . 
     The chamber base  188  includes a plurality of channels  157  formed therein for a coolant, such as water, to flow therethrough. Cooling the chamber base  188  also draws heat from, and thus cools, the cooling member  151 . The cooling member  151  may be fabricated from a material having high heat conductivity, such as a metal, for example, aluminum. The cooling member  151 , in turn, functions as a heat sink to the substrate support  191  due to close proximity of the cooling member  151  to the substrate support  191 . 
     The cooling member  151  includes a recess  104  formed in the surface thereof that is in contact with the first surface  120  of the chamber base  188 . The recess  104  can be used to circulate a cooling fluid for further cooling of the cooling member  151 . In one embodiment, which can be combined with other embodiments, the cooling member  151  is an annular ring, and the recess  104  is an annular recess. A cooling gas may be flowed from a gas source  106  through the cooling member  151  via the recess  104  to provide additional cooling of the cooling member  151 . The cooling gas increases heat transfer between the cooling member  151  and the substrate support  191 , thus further cooling the substrate support  191 . The cooling gas may be helium, nitrogen, or other suitable gas. The cooling gas flows through a passage  108  formed in the chamber base  188  and through a channel  105  defined between the recess  104  and the first surface  120  of the chamber base  188 . 
     The controller  1002  is configured to control various operations of the system  101  described above. The controller  1002  is also configured to control various operations described herein. The controller  1002  is coupled to at least one or more of the lamps  155 , the vacuum pump  1001 , the PCV  169 , the rotatable valve  182 , the pump motor  117 , the stator  195 , the first gas source  109 , the supply valve  123 , the motor  124 , and/or the motor  132  (shown in  FIG. 2A ). The controller  1002  is configured to cause one or more of the operations of the method  300  described below to be conducted. The controller  1002  includes a non-transitory computer-readable medium. The controller  1002  includes a processor, support circuitry, and instructions that—when executed by the processor—cause the operations to be conducted. 
     The instructions of the controller  1002  can include one or more machine learning/artificial intelligence algorithms that can be executed in addition to the operations described herein. As an example, a machine learning/artificial intelligence algorithm executed by the controller  1002  can optimize and alter a pulse frequency (e.g., an oscillation frequency) of the supply of process gases based on a residence time frequency of reactants within the interior volume  102 . The pulse frequency is the inverse of the residence time frequency. The machine learning/artificial intelligence algorithm can account for a measured residence time frequency, a known volume amount of the interior volume  102 , and composition(s) of the process gases  111 ,  131 . 
       FIG. 1B  is an enlarged partial schematic view of the system  101  shown in  FIG. 1A  during the processing operation, according to one implementation.  FIG. 1B  illustrates a flow  140  of the one or more process gases  111  and/or the one or more process gases  131  between the substrate  192  and the window  135 . The flow  140  has a flow profile with a peak velocity  141 . In one embodiment, which can be combined with other embodiments, the peak velocity  141  is about 50 meters per second. The flow  140  has a boundary layer  142 . The boundary layer  142  has a thickness T 1 . The boundary layer  142  having the thickness T 1  is a portion of the flow  140  that is on the side of the peak velocity  141  adjacent the upper surface  133  of the substrate  192  where a velocity is within a range of 5% to 10% of the peak velocity  141 . 
     The substrate  192  includes a 3D feature  143  formed in the upper surface  133 . The 3D feature  143  can include one or memory holes, one or more vias, and/or one or more trenches. In the implementation shown, the 3D feature  143  is a memory hole. The 3D feature  143  extends into the substrate by a depth D 2  of about 10 micrometers. The flow  140  of the one or more process gases  111  and/or the one or more process gases  131  moves over the upper surface  133 . During the moving of the flow  140 , reactants of the one or more process gases  111  and/or the one or more process gases  131  flow vertically into and out of the 3D feature  143 . In one embodiment, which can be combined with other embodiments, the reactants flow vertically into and out of the 3D feature  143  in a manner that achieves effusion, where a mean flow path of the reactants is larger than a hole diameter of the 3D feature  143  such that the reactants of the process gases  111 ,  131  quickly flow into and out of the 3D feature  143 . Effusion is facilitated, for example, using oscillation of the boundary layer  142  as described herein. 
       FIG. 1C  is a schematic graphical illustration of an oscillation frequency  145 , according to one implementation. As shown in  FIG. 1C , the oscillation frequency has a sinusoidal profile, which can be used for the various parameters described herein that are oscillated. The “P” of the vertical axis represents units of an operational parameter described herein, such as the pressure in the interior volume  102 , an amount of the one or more processing gases  111  and/or the one or more processing gases  131  in the interior volume  102 , the height H 1 , the distance D 1 , and/or the distance D 2 . In one embodiment, which can be combined with other embodiments, oscillating such parameters oscillates the thickness T 1  of the boundary layer  142  and/or a distance of the boundary layer  142  relative to the substrate  192 . In one embodiment, which can be combined with other embodiments, oscillating such parameters oscillates the thickness T 1  of the boundary layer  142 . The “T” of the horizontal axis” represents time. 
       FIG. 2A  is a schematic partial top view of the system  101  shown in  FIG. 1A , according to one implementation. A second inlet path  146  having a supply valve  147  joins with the first inlet path  107  leading to the gas inlet  197 . The supply valve  147  disposed along the second inlet path  146  is fluid coupled to a second gas source  148 . The linear showerhead  126  of the gas injection assembly  125  is fluidly coupled to a first supply path  170  and a second supply path  149 . To oscillate an amount of the one or more processing gases  131  in the interior volume  102  supplied using the gas injection assembly  125  (thus oscillating the pressure within the interior volume  102 ), a first supply valve  163  coupled to the first gas source  109  along the first supply path  170  is opened while a second supply valve  164  is closed. The second supply valve  164  is downstream from the first supply valve  163  along the first supply path  170 . Opening the first supply valve  163  while the second supply valve  164  is closed charges a charge volume of a line  165  between the first supply valve  163  and the second supply valve  164 . After the opening of the first supply valve  163 , the first supply valve  163  is closed and the second supply valve  164  is opened while the first supply valve  163  is closed to introduce the one or more process gases from the first gas source  109  into the interior volume  102 . Opening the second supply valve  164  runs and releases the process gases from the charge volume of the line  165  into the interior volume  102 . The opening the first supply valve  163  while the second supply valve  164  is closed, the closing of the first supply valve  163 , and the opening the second supply valve  164  while the first supply valve  163  is closed can be repeated to pulse the supply of the process gases from the first gas source  109 . 
     The second supply path  149  includes a first supply valve  166  and a second supply valve  167  disposed along the second supply path  149 . The first supply valve  166  and the second supply valve  167  can be operated in a manner similar to the first supply valve  163  and the second supply valve  164  of the first supply path  170  to pulse the supply of the one or more process gases from the second gas source  148 . A charge volume of a line  168  between the first supply valve  166  and the second supply valve  167  is used to pulse the supply of the one or more process gases from the second gas source  148 . The process gases from the first supply path  170  and the process gases from the second supply path  149  join at a gas block  171 . The gas block  171  is fluidly coupled to the linear showerhead  126  through a gas conduit  172 . The gas block  171  and/or the gas conduit  172  extend at least partially through a sidewall (such as the first portion  184 ) of the chamber body  185 . 
     In the implementation shown in  FIG. 2A , the first gas source  109 , the second gas source  148 , the supply valve  123 , the supply valve  147 , the first supply valve  163 , and the first supply valve  166  are disposed within a gas box  173 . The present disclosure contemplates that respective orifices of the valves  163 ,  164 ,  166 , and  167  may be varied (e.g., altered) without completely closing or completely opening the orifices to pulse the supply of the one or more process gases  131  and oscillate an amount of the one or more process gases  131  in the interior volume  102 . The respective orifices may be oscillated. The present disclosure contemplates that the respective valves  163 ,  164 ,  166 , and  167  may be completely closed and completely opened to pulse the supply of the one or more process gases  131  and oscillate an amount of the one or more process gases  131  in the interior volume  102 . In one embodiment, which can be combined with other embodiments, the supply of the one or more process gases  111  is provided at a substantially constant gas flow while the boundary layer is oscillated as described herein. In one embodiment which can be combined with other embodiments, each of the first supply valve  163  and the first supply valve  166  is a fast valve having a cycle rate (a rate at which the valve can open and close) that is 0.02 seconds-per-gas or less. In one embodiment, which can be combined with other embodiments, the cycle rate is 0.01 seconds-per-gas. In one example, which can be combined with other examples, each fast valve pulses two gases at the cycle rate of 0.01 seconds-per-gas or less such that a single pulse cycle of the two gases lasts 0.02 seconds or less. In one embodiment, which can be combined with other embodiments, each of the first supply valve  163  and the first supply valve  166  is a fast valve having a switching rate (a rate at which the valve switches between open and close) that is 0.01 seconds or less. 
     Each of the second gas source  148 , the supply valve  147 , the first supply valve  163 , the second supply valve  164 , the first supply valve  166 , and/or the second supply valve  167  can be coupled to the controller  1002  (shown in  FIG. 1A ) to control the operations thereof. 
       FIG. 2B  is a schematic partial top view of the system  101  shown in  FIG. 1A , according to one implementation. The implementation shown in  FIG. 2B  is similar to the implementation shown in  FIG. 2A . In the implementation shown in  FIG. 2B , the first supply valve  163  and the first supply valve  166  are disposed outside of the gas box  173  and further downstream along the respective first supply path  170  and second supply path  149 . In the implementation shown in  FIG. 2B , a first charge volume  175  is positioned between the first supply valve  163  and the second supply valve  164  along the first supply path  170 , and a second charge volume  176  is positioned between the first supply valve  166  and the second supply valve  167  along the second supply path  149 . Each of the first charge volume  175  and the second charge volume  176  is part of a respective container having a pressure gauge  177 ,  178  coupled thereto. Each of the first charge volume  175  and the second charge volume  176  has an internal width (such as an internal diameter) that is larger than an internal width (such as internal diameter) of the respective first or second supply path  170 ,  149 . The first charge volume  175  and the second charge volume  176  can be charged and ran (e.g., released), as described for the charge volumes of the lines  165 ,  168  of the implementation shown in  FIG. 2A . 
       FIG. 3  is a schematic view of a method  300  of processing a substrate, according to one implementation. Operation  302  of the method  300  includes conducting a processing operation on the substrate in an interior volume of a processing chamber. The processing operation includes one or more of an oxidation operation, a plasma immersion ion implantation operation, an epitaxial deposition operation where, a chemical vapor deposition (CVD) operation, a physical vapor deposition (PVD) operation, an atomic layer deposition (ALD) operation, an etching operation, and/or a thermal annealing operation. The oxidation operation oxidizes at least a portion of the substrate. The plasma immersion ion implantation operation includes immersing the substrate in plasma and implanting ions on or into the substrate. The epitaxial deposition operation includes growing an epitaxial layer on the substrate. 
     Operation  304  of the method  300  includes moving a flow of one or more process gases over a surface of the substrate. The moving the flow of one or more process gases includes flowing reactants of the one or more process gases into a 3D feature of the substrate. The flow of one or more process gases includes a peak velocity and a boundary layer at a distance relative to the substrate. The boundary layer includes a thickness. In one example, the process gases flow generally parallel to an upper surface of a substrate in a “cross flow” regime. Operation  306  of the method  300  includes oscillating the boundary layer of the flow of one or more process gases while the flow of one or more process gases moves over the surface of the substrate. The oscillating the boundary layer at operation  306  includes oscillating one or more of the thickness of the boundary layer and/or the distance of the boundary layer relative to the substrate. The oscillating the boundary layer includes one or more of: oscillating a pressure of the interior volume, oscillating an amount of the one or more process gases introduced into the interior volume, and/or oscillating a height of the substrate in the interior volume. One or more of the pressure, the amount, the height, and/or the distance is oscillated at an oscillation frequency that is within a range of 100 Hz to 1,000 Hz. One or more of the pressure, the amount, the height, and/or the distance is oscillated along a sinusoidal profile. 
     In one embodiment, which can be combined with other embodiments, the oscillating the pressure of the interior volume includes exhausting the one or more process gases from the interior volume through a rotatable valve positioned along an exhaust path of the processing chamber. The rotatable valve includes a flapper that is freely rotatable relative to a valve housing. In one example, which can be combined with other examples, the rotatable valve is a butterfly valve. The oscillating the pressure of the interior volume also includes rotating the flapper using a pump motor coupled to the rotatable valve. The flapper is rotated at a speed of 1,000 rotations-per-minute (RPM&#39;s) or greater. The oscillating the pressure of the interior volume also includes exhausting the one or more process gases through a pressure control valve positioned downstream from the rotatable valve along the exhaust path. In one embodiment, which can be combined with other embodiments, the oscillating the pressure includes oscillating within a pressure range that is 1% to 10% of a mean pressure. 
     In one embodiment, which can be combined with other embodiments, the oscillating the amount of the one or more process gases in the interior volume includes opening a first supply valve coupled to a gas source along a supply path while a second supply valve is closed. The second supply valve is downstream from the first supply valve along the supply path. The oscillating the amount also includes, after the opening the first supply valve, closing the first supply valve and opening the second supply valve while the first supply valve is closed. The oscillating the amount of the one or more process gases can include repeating the operations of closing the second supply valve, opening the first supply valve while the second supply valve is closed, closing the first supply valve, and opening the second supply valve while the first supply valve is closed to oscillate the amount of the one or more process gases. In one embodiment, which can be combined with other embodiments, a charge volume is positioned between the first supply valve and the second supply valve along the supply path. The charge volume has an internal width that is larger than an internal width of the supply path. 
     In one embodiment, which can be combined with other embodiments, the oscillating the height of the substrate in the interior volume includes oscillating a substrate support upward and downward. The substrate is disposed on the substrate support such that the substrate is oscillated upward and downward. The oscillating the height of the substrate in the interior volume oscillates a processing region of the interior volume. 
     In one embodiment, which can be combined with other embodiments, the oscillating the boundary layer at operation  306  includes oscillating a distance between a ceiling of the interior volume and the surface of the substrate. The oscillating the distance between the ceiling of the interior volume and the surface of the substrate oscillates the processing region of the interior volume. In one embodiment, which can be combined with other embodiments, the oscillating the distance between the ceiling of the interior volume and the surface of the substrate includes oscillating upward and downward at least a portion of an upper component (such as a showerhead, a gas distribution plate, and/or a window) that at least partially defines the ceiling. In one embodiment, which can be combined with other embodiments, the oscillating the distance between the ceiling of the interior volume and the surface of the substrate includes oscillating upwardly and downwardly a diaphragm that at least partially defines the ceiling. 
     In one embodiment, which can be combined with other embodiments, the oscillating the boundary layer at operation  306  includes oscillating a distance between a gas injection assembly and the surface of the substrate. The gas injection assembly is used to introduce the flow of one or more process gases into the interior volume and move the flow of one or more process gases at operation at operation  304 . 
     Benefits of the present disclosure include achieved effusion of reactants into and out of a 3D feature of substrates, enhanced chemical reactions of process gases with substrates, enhanced flow of reactants to surfaces of substrates, increased throughput, reduced downtime, and increased conformality including for substrates having high aspect ratios. 
     It is contemplated that one or more aspects disclosed herein may be combined. As an example, one or more aspects, features, components, and/or properties of the system  101  and the method  300  may be combined. Moreover, it is contemplated that one or more aspects disclosed herein may include some or all of the aforementioned benefits. 
     While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The present disclosure also contemplates that one or more aspects of the embodiments described herein may be substituted in for one or more of the other aspects described. The scope of the disclosure is determined by the claims that follow.