Patent Publication Number: US-2023133402-A1

Title: Injection module for a process chamber

Description:
BACKGROUND 
     Field 
     The present disclosure generally relates to thin film materials, in particular the deposition, modification, or removal of thin film materials on a substrate, such as a semiconductor substrate. More particularly, the present disclosure relates to a gas injection module for a process chamber, such as a rapid thermal processing (RTP) process chamber. 
     Description of the Related Art 
     The deposition of, modification of, or removal of thin film materials on a substrate depends in large part on flux of precursor gases across the surface of the substrate. During substrate rotation, rotational velocity (i.e., rotational spin rate) often dominates over precursor gas flow rate within the process chamber. Especially at process volume pressure ranges of about 100 Torr or more, low relative gas flow rate (in comparison to rotational spin rate) may cause low flux at the center of the substrate. The area of low flux at the center of the substrate may be referred to as a “stagnation region.” In some examples, such as radical oxidation, relatively low growth of oxide thin film occurring in the stagnation region at the center of the substrate (compared to the edge region) may lead to undesirably high film thickness non-uniformity across the surface of the substrate. Therefore, there is a need for apparatus and methods that improve precursor gas flux across the surface of the substrate. 
     SUMMARY 
     In some embodiments, a process chamber suitable for use in semiconductor manufacturing is provided. The process chamber includes a chamber body, a rotatable substrate support disposed inside a process volume of the chamber body, the substrate support configured to have a rotational spin rate; an inlet port formed in the chamber body, and an injection module coupled to the inlet port. The injection module includes a body, one or more gas inlets coupled to the body, and a plurality of nozzles formed in a supply face of the body, the supply face configured to face inside the chamber body, and gas exiting from the injection module configured to have a flow rate. The process chamber also includes a controller configured to operate the process chamber such that the ratio of the flow rate to the rotational spin rate is between about 1/3 and 3. 
     In some embodiments, a process chamber is provided. The process chamber includes a chamber body, a rotatable substrate support disposed inside the chamber body; an inlet port formed in the chamber body, and an injection module coupled to the inlet port. The injection module includes a body, one or more gas inlets coupled to the body, and a plurality of nozzles formed in a supply face of the body, the supply face configured to face inside the chamber body, wherein the supply face has a void area with a larger spacing between proximate adjacent nozzles compared to spacing between other adjacent pairs of nozzles of the plurality of nozzles. 
     In some embodiments, a process chamber is provided. The process chamber includes a chamber body, a rotatable substrate support disposed inside a process volume of the chamber body, an inlet port formed in the chamber body, and an injection module coupled to the inlet port. The injection module includes two or more body portions; for each adjacent pair of the two or more body portions, a vertical partition separating the adjacent body portions; for each of the two or more body portions, a gas inlet coupled to the corresponding body portion, and to a gas conduit coupled to the corresponding gas inlet; and for each of the two or more body portions, a plurality of nozzles formed in a supply face of the corresponding body portion. 
    
    
     
       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 of the disclosure and are therefore not to be considered limiting of its scope, as the disclosure may admit to other equally effective embodiments. 
         FIG.  1    is a cross-sectional view of a process chamber, according to some embodiments. 
         FIG.  2 A  is a plan view of the process chamber of  FIG.  1   , according to examples of the present disclosure. 
         FIG.  2 B  is a plan view of the process chamber of  FIG.  1   , according to some embodiments. 
         FIGS.  3 A- 3 D  are isometric views of various injection modules that may be used in the process chamber of  FIG.  1   , according to examples of the present disclosure. 
         FIGS.  4 A- 4 D  are cross-sectional views of various injection modules that may be used in the process chamber of  FIG.  1   , according to examples of the present disclosure. 
         FIG.  4 E  is a schematic isometric view of an injection module that may be used in the process chamber of  FIG.  1   , according to examples of the present disclosure. 
     
    
    
     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 
     The present disclosure relates to a gas injection module for a process chamber having a process volume pressure range of about 100 Torr or more. The injection module may beneficially increase gas flux across one or more regions of the surface of a substrate. The injection module may beneficially increase relative gas flow rate, as compared to rotational spin rate. The injection module may beneficially improve gas flow directionality, as compared to conventional chamber designs. The injection module may enable greater reaction uniformity and/or tunability across one or more regions of the surface of a substrate disposed in the process chamber. 
     Injection module embodiments of the present disclosure provide increased relative gas flow rate and improved gas flow directionality compared to previous gas injection modules or showerhead designs. The provided gas flow rate may match or exceed the rotational spin rate of the substrate support within the process chamber. The provided gas flow rate and directionality may enable displacement of gas from the stagnation region at or near the center of the substrate. Improved displacement of gas from the stagnation region may increase reactivity proximate the center of the substrate, thereby improving center-to-edge (C-E) reaction uniformity. 
     In one example, the gas flow rate is about 0.5 times to about 2.0 times the rotational spin rate of the substrate support at the perimeter thereof. In one example, the perimeter of the substrate support is approximately at the extent of the diameter of the substrate support which supports the substrate. In one example, the gas flow rate may be greater than about 0.1 meters per second (m/s) and less than about 6 m/s, depending on the rotational spin rate of the substrate support, the process volume pressure, and the size of the substrate. In another embodiment, the gas flow rate may be greater than about 6 m/s. In other embodiments, the substrate may be a 200 mm wafer, a 300 mm wafer or a 450 mm wafer. For example, for a 200 mm, 300 mm, and 450 mm wafer, the gas flow rate may be between about 0.3 m/s and about 2.6 m/s, between about 0.4 m/s and about 3.8 m/s, and between about 0.7 m/s and about 5.7 m/s, respectively. 
     Injection module embodiments of the present disclosure may enable improved control of gas flow distribution and/or directionality within the process chamber compared to previous gas injection modules or showerhead designs. The rate, distribution, and/or directionality of gas flow may be adjustable, which thereby may improve gas flux and reaction uniformity. 
       FIG.  1    is a cross-sectional view of an exemplary process chamber  110  that may be used to practice the methods set forth herein. As shown in  FIG.  1   , the process chamber  110  is a rapid thermal processing (RTP) chamber, although other types of chambers may be used. In general, the process chamber  110  holds a substrate  132  for processing in a gaseous environment according to examples of the present disclosure. 
     In general, the process chamber  110  is configured to receive the substrate  132  therein and rotate the substrate  132  while receiving energy into the process chamber  110  to heat the substrate  132  to an elevated temperature. The elevated temperature of the substrate  132  results in a faster reaction rate of reactant species introduced into the process chamber  110  with the substrate  132  or portions of a thin film material layer on the substrate  132 . In some examples, the substrate  132  may be a semiconductor substrate (e.g., formed from silicon). As shown in  FIG.  1   , the substrate  132  is supported on an edge ring  130 . The edge ring  130  is disposed on a substrate support  128 . In other embodiments, it is contemplated that the substrate  132  is directly supported on the substrate support  128 . The substrate support  128  is coupled to a rotor  126 . The rotor  126  may be annular, as shown in  FIG.  1   . The rotor  126  is configured to rotate the substrate  132  about a center axis  175  of the rotor  126 , to allow uniform heating of the substrate  132  via the energy source of the process chamber  110 . The rotor  126  may be configured to rotate the substrate  132  at a rotational spin rate of greater than or equal to about 0.5 Hertz, such as about 2 Hertz or greater, such as about 4 Hertz or greater. 
     Process chamber  110  may have a process volume pressure range of about 100 Torr or more. It is currently believed that, for chambers operating at process volume pressure ranges of about 100 Torr to about 600 Torr, and with substrate rotational frequency of greater than or equal to about 2 Hertz, the rotational convective drag forces spin-up the gas velocity near 1-2 m/s. It is also currently believed that such convective drag forces impede migration of fresh reactants to the center of the substrate. The process chamber  110  includes a chamber body  120  having a sidewall portion  121  and a lower portion  123 . A window  122  is disposed on the sidewall portion  121  of the chamber body  120 , such that a process volume  170  is formed between the window  122  and the substrate support  128 . In some examples, the window  122  may be transparent to electromagnetic energy. A rapid annealing lamp assembly  116  is disposed over the window  122 . In one embodiment, which can be combined with other embodiments disclosed herein, the lamp assembly  116  is less than or equal to about 3 centimeters (cm) from the substrate support, such as about 2 cm or less above the substrate support. The lamp assembly  116  includes a housing  154  and a plurality of lamps  146 , disposed in the housing  154 . Each lamp  146  is disposed within a corresponding opening  153  in the housing  154 . The lamps  146  are connected to a power supply controller  176  via a plurality of electrical sockets  148  (e.g., one socket  148  for each lamp  146 ). During operation, the lamps  146  emit radiation through the window  122  towards the substrate  132  disposed in the process chamber  110  to heat the substrate  132  to a predetermined temperature. In some examples, the predetermined temperature may be within a range of about 20° C. to about 1,500° C., such as about 200° C. to about 1,300° C. 
     In some examples, the window  122  may be formed from a material resistant to the processing environment (e.g., a material that maintains rigidity when exposed to elevated temperatures and/or a material that is transparent to radiation emitted by the lamps  146 ). In some examples, the window  122  may be formed from quartz or sapphire. In some examples, the window  122  may be coated with an anti-reflective coating. As shown in  FIG.  1   , a filter  119  is coated on an inside surface of the window  122  (i.e. facing the substrate support  128 , as shown). In some examples, one or more filters may be disposed on one or both sides of the window  122 . In some examples, if the lamps  146  have significant ultraviolet (UV) light output, one or more UV filters may be used to limit or prevent the transmission of UV ions and/or radicals from the lamps  146  into the process chamber  110  to reduce UV damage to UV sensitive structures on the substrate  132 . In some examples, one or more notch filters may be used to admit narrow band radiation. 
     In some embodiments, the filter  119  blocks radiation at wavelengths within a specific range of about 780 nm to about 880 nm, while transmitting radiation at wavelengths outside the specific range. In some examples, the filter  119  may be formed from a plurality of alternating layers, such as alternating oxide layers. In some examples, the filter  119  may include alternating silicon dioxide layers and titanium dioxide layers with the silicon dioxide layers being located at opposite ends of the filter  119 . In some examples, the filter  119  may include 30 to 50 alternating layers. In some examples, the filter  119  may be coated onto an outside surface of the window  122  (i.e., facing the lamp assembly  116 ), coated onto an inside surface of the window  122  (i.e., facing the substrate support  128 , as shown), or embedded in the window  122 . 
     An inlet port  180  and an outlet port (e.g.,  182  in  FIG.  2 A ) are formed in the sidewall portion  121  of the chamber body  120 . In some examples, operating pressure within the process chamber  110  may be reduced to a sub-atmospheric pressure before introducing a process gas through the inlet port  180 . A vacuum pump  184  (shown schematically in  FIG.  1   ) evacuates the process chamber  110  by pumping gas from the interior of the process chamber  110  through an exhaust port  186  formed in the sidewall portion  121  of the chamber body  120 . A valve  188  disposed between the exhaust port  186  and the vacuum pump  184  is utilized to control the pressure within the process chamber  110 . In some other examples, the process chamber  110  may be operated with process volume pressure in the range of about 100 Torr or more, for example, from about 100 Torr to about 600 Torr. A second vacuum pump  192  (shown schematically in  FIG.  1   ) is connected to the lamp assembly  116  to reduce the pressure within the lamp assembly  116 , particularly when the pressure within the process chamber  110  is pumped to a reduced pressure to reduce the pressure differential across the window  122 . The pressure within the lamp assembly  116  is controlled by a valve  194 . 
     An annular channel  124  is formed in the chamber body  120 . The channel  124  is located adjacent the lower portion  123  of the chamber body  120 . The rotor  126  and the substrate support  128  are disposed in the channel  124 . As shown in  FIG.  1   , the substrate support  128  is a cylinder. In some examples, the substrate support  128  is formed from a material having high heat resistivity (e.g., black quartz). The edge ring  130  is disposed on the rotatable substrate support  128  and may be in contact with the substrate  132 . As shown in  FIG.  1   , a plane of the edge ring  130  is parallel to the X-Y plane (horizontal). A rotor cover  127  is disposed on the lower portion  123  of the chamber body  120  outside the edge ring  130 . The channel  124  has an outer wall  150  (i.e. radially outward relative to an inner wall  152 ) and the inner wall  152 . A lower portion  155  of the outer wall  150  has a first radius and an upper portion  156  of the outer wall  150  has a second radius greater than the first radius. A middle portion  158  of the outer wall  150  connecting the lower portion  155  to the upper portion  156  extends linearly therebetween, forming a slanted surface that faces toward the edge ring  130 . The rotor cover  127  has a first portion  160  that rests on an upper surface  123   a  of the lower portion  123  of the chamber body  120  and a second portion  162  that extends into the channel  124  along the upper portion  156  of the outer wall  150 . The rotor cover  127  extends partially over an opening  177  the channel  124  to prevent deposition or buildup of particles caused by the flow of precursor gas into the process chamber  110 . As shown in  FIG.  1   , the rotor cover  127  is an annular ring. In some examples, the rotor cover  127  may be formed from a ceramic material (e.g., alumina). The rotor cover  127  includes a first surface  131  facing the window  122 . As shown in  FIG.  1   , the first surface  131  is parallel to the window  122  to prevent the reflection of radiant energy towards the substrate  132 . In some other examples, the first surface  131  may be slanted downwards from outside to inside (i.e., radially inward). In other examples, the first surface  131  may be slanted downwards from inside to outside (i.e., radially outward). 
     A stator  134  is located external to the chamber body  120  in a position axially aligned with the rotor  126 . In some embodiments, the stator  134  is a magnetic stator, and the rotor  126  is a magnetic rotor. During operation, the rotor  126  is turned relative to the stator  134 , which in turn rotates the substrate support  128 , the edge ring  130 , and the substrate  132  supported thereon. 
     During operation, heat retained in the edge ring  130  can cause the temperature at the edge of the substrate  132  to be higher than the temperature at the center of the substrate  132 . In some examples, a thickness of the edge ring  130  may be over-sized to provide extra thermal mass to act as a heat sink, which helps avoid overheating the edge of the substrate  132 . In some embodiments, a cooling member  143  is located near the edge ring  130  to act as a heat sink for cooling the edge ring  130 . The cooling member  143  is disposed on a chamber base  125 . The chamber base  125  is coupled to the chamber body  120 . The chamber base  125  includes a first surface  171  and a second surface  172  opposite the first surface  171 . As shown in  FIG.  1   , the cooling member  143  is in direct contact with the first surface  171  of the chamber base  125 . In some examples, the cooling member  143  may be formed from a material having high heat conductivity (e.g., a metal, such as aluminum or copper, etc. . . . ). A channel  137  is formed in the chamber base  125  for providing a flow of coolant (e.g., water) to the chamber base  125 . In operation, coolant supplied to the channel  137  is able to cool the chamber base  125  as well as the cooling member  143  located near the chamber base  125 . In one embodiment, which can be combined with other embodiments disclosed herein, it is contemplated that there are multiple cooling channels  137  formed in the chamber base  125 . 
     A fin  140  is formed on the edge ring  130  to provide extra thermal mass. In some examples, the fin  140  may be continuous or discontinuous. In some embodiments, the fin  140  is cylindrical. In some examples, the fin  140  may include a plurality of discrete fins. The fin  140  is formed on a surface of the edge ring  130  that is facing towards the channel  124 . As shown in  FIG.  1   , the fin  140  extends into the channel  124 . In some other examples, the fin  140  may be formed on a surface of the edge ring  130  that is facing towards the window  122 . In both embodiments, the fin  140  is substantially perpendicular to a plane of the edge ring  130 . 
       FIG.  2 A  is a plan view of the process chamber  110 , according to examples of the present disclosure, showing the process volume  170  of the process chamber  110  with the lamp assembly  116  removed.  FIG.  2 B  is a plan view of the process chamber  110  with the lamp assembly  116  removed, according to some embodiments. As shown in  FIG.  2 A , the process chamber  110  has a slit valve  203  that allows access into the chamber body  120  through an opening in an outer wall of the chamber body  120 . The slit valve  203  may be coupled to a transfer chamber having a transfer robot disposed therein. The slit valve  203  allows the substrate  132  to be loaded into and removed from the process volume in the interior of the chamber body  120  (e.g., using a robotic end effector of the transfer robot). The slit valve  203  is located across from an outlet port  182  formed in the chamber body  120 . A door  207  closes over and seals off the opening to allow the environment of the process volume to be controlled independently of ambient conditions outside the chamber body  120 . 
     As shown in  FIG.  2 A , the slit valve  203  is located 90° counterclockwise from the inlet port  180 . The outlet port  182  is located 270° counterclockwise from the inlet port  180 . The outlet port  182  is located 180° from the slit valve  203 . Therefore, when the substrate  132  is rotated in a counterclockwise direction, gas flow is swept at least 270° around the interior of the chamber body  120  before being exhausted through the outlet port  182 . However, the inlet port  180 , the outlet port  182 , and the slit valve  203  may be positioned at various optional locations relative to each other. In some examples, the outlet port  182  may be located 90° counterclockwise or 180° from the inlet port  180 . Similarly, for clockwise rotation, the outlet port  182  may be located 90°, 180°, or 270° clockwise from the inlet port  180 . In some examples, the slit valve  203  may be located 180° from the inlet port  180 . In some examples, the outlet port  182  and the slit valve  203  may coincide with each other (e.g., being located on the same side of the chamber body  120 ). In some examples, the outlet port  182  is level on an X-Y plane with the inlet port  180 . 
     As shown in  FIG.  2 A , a remote plasma source (RPS)  200  is coupled to the process chamber  110  upstream of the inlet port  180 . In some examples, the RPS  200  may provide vaporization or plasma generation of precursor gases that are subsequently provided to the process chamber  110  for interacting with the substrate  132 . In other examples, there is no RPS  200  connected with the inlet port  180 . In an embodiment without the RPS  200 , a mixture of inert gas and precursor gas is directly supplied to the process chamber  110  through the inlet port  180 . In some examples, the precursor gases may include one or more reactive gases (e.g., water (e.g., H 2 O) or heavy water (e.g., D 2 O)) and/or inert gases (e.g., hydrogen (e.g., H 2 ) or argon (e.g., Ar)) (also referred to as “carrier gases”). In some examples, the reactive gases may be vaporized to form steam. The RPS  200  is coupled to a gas supply  208  from a gas panel through a first conduit  201 . The RPS  200  is coupled to the inlet port  180  through a second conduit  202 . As shown in  FIG.  2 A , the second conduit  202  has a manifold  204  at a distal end relative to the RPS  200  for providing volume expansion of gas flow leading to the inlet port  180 . 
     As shown in  FIG.  2 A , an injection module  206  is coupled between the inlet port  180  and the manifold  204  of the second conduit  202 . In some other embodiments, the second conduit  202  is coupled directly to the injection module  206  without the manifold  204  (e.g., as shown in  FIGS.  3 A and  3 C ). In some other embodiments, the second conduit  202  is split into multiple different gas flow paths that are independently coupled directly to the injection module  206  without the manifold  204  (e.g., as shown in  FIGS.  3 B and  3 D ). The injection module  206  enables control over the rate, distribution, and/or directionality of gas flow to the process chamber  110 , as described in more detail below. The injection module  206  may be configured such that the inlet port  180  is substantially coplanar to the second conduit  202  and/or manifold  204 , allowing for a decrease in the size of the injection module  206 . The planarity of the second conduit  202 , the injection module  206 , and the inlet port  180  may provide adequate expansion space for the process gas, facilitating more even gas distribution, while minimizing hardware size/space. In contrast, as is done in prior approaches, injected process gases follow non-linear (or non-planar) paths, resulting in turbulent flow and/or uneven gas distribution. To minimize the turbulent flow and/or uneven gas distribution, relatively large manifolds are used in conventional approaches, resulting in larger hardware footprints. 
     The injection module  206  is configured to manage the gas flow from the second conduit  202  such that the rate, distribution, and/or directionality of the gas flow is within a desired range. In one example, the ratio of the flow rate of gas exiting from the injection module  206  to the rotational spin rate of the substrate support is between about one-third and about three, such as between about one-half and about two. If the ratio of the flow rate of gas exiting from the injection module  206  to the rotational spin rate of the substrate support is too low, then the precursor gas may be unable to reach the center of the substrate, and, thus, unable to displace the gas in the stagnation region proximal to the center of the substrate  132 , possibly resulting in non-uniform deposition. If the ratio of the flow rate of gas exiting from the injection module  206  to the rotational spin rate of the substrate support is too high, then the precursor gas may overshoot the stagnation region proximal to the center of the substrate  132 , possibly resulting in non-uniform deposition. In some examples, gas flow into the process chamber  110  may include a combined mixture of two or more gases. In one example, gas flow may include a mixture of hydrogen and water (e.g., steam). In another example, gas flow may include a mixture of argon and water (e.g., steam). 
     In some embodiments, the controller  176  ( FIG.  1   ) is configured to control a flow rate of gas exiting from the injection module  206 . In some embodiments, the controller  176  is configured to control a rotational spin rate of the substrate support. In some embodiments, the controller  176  is configured to control a pressure of the process volume. In some embodiments, the controller is configured to control a ratio of the flow rate of gas exiting from the injection module  206  to the rotational spin rate of the substrate support, for example, setting and/or maintaining the ratio between about one-third and about three, such as between about one-half and about two. The controller  176  generally includes the one or more processors, memory, and support circuits. The one or more processors may include a central processing unit (CPU) and may be one of any form of a general purpose processor that can be used in an industrial setting. The memory, or non-transitory computer-readable medium, is accessible by the one or more processors  184  and may be one or more of memory such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. The support circuits are coupled to the one or more processors and may comprise cache, clock circuits, input/output subsystems, power supplies, and the like. The various methods disclosed herein may generally be implemented under the control of the one or more processors by the one or more processors executing computer instruction code stored in the memory as, for example, a software routine. When the computer instruction code is executed by the one or more processors, the one or more processors controls the chamber  100  to perform processes in accordance with the various methods. 
     As shown in  FIGS.  2 A- 2 B , an additional inlet port  210  is formed in the chamber body  120 . The positions of the outlet port  182  and the inlet port  210  are interchangeable. In some embodiments, gas flow occurs through both inlet ports  180 ,  210  simultaneously or at different intervals during the same process. The inlet port  210  may be located 90, 180, or 270 degrees counterclockwise from the outlet port  182 . Gas flow through the inlet port  210  may be controlled using an injection module set forth herein. For example, each inlet port  180 ,  210  may have an injection module with a single gas inlet (shown in  FIGS.  3 A and  3 C ) or multiple gas inlets (shown in  FIGS.  3 B and  3 D ). In one example, only inlet port  180  has an injection module with a single gas inlet. In another example, only inlet port  180  has an injection module with multiple gas inlets. In another example, each inlet port  180 ,  210  has an injection module with a single gas inlet. In yet another example, each inlet port  180 ,  210  has an injection module with multiple gas inlets. 
       FIGS.  3 A- 3 D  are isometric views of various injection modules that may be used in the process chamber  110 , according to examples of the present disclosure. The embodiments of  FIGS.  3 A- 3 D  may be combined with other embodiments disclosed herein.  FIG.  3 A  illustrates an injection module  300  having a body  302 , a single gas inlet  304 , configured to couple to the body  302 , and a plurality of nozzles  306  formed in a supply face  308  of the body  302 . The supply face  308  is configured to face the interior of the process chamber  110  when in operation. The plurality of nozzles  306  have a pitch defined by the horizontal distance between the centers of adjacent nozzles  306 . As shown in  FIG.  3 A , the nozzles  306  are aligned in a vertical (Z) direction. In other words, the nozzles  306  are located on the same horizontal (X-Y) plane. In some embodiments, the body  302 , the gas inlet  304 , and the nozzles  306  are configured to be coplanar (i.e., in the same plane, here the X-Y plane) with the second conduit  202  (shown in  FIG.  2 A ). In some other embodiments, one or more of the body  302 , the gas inlet  304 , the nozzles  306 , or combinations thereof are not aligned in the same plane with the second conduit  202 . The supply face  308  is configured to be perpendicular to a plane of the edge ring  130  and perpendicular to a surface of the substrate  132  contacting the edge ring  130 . In some examples, a vertical spacing (measured in the Z direction) between the surface of the substrate  132  and the nozzles  306  may be within a range of about 5 mm to about 15 mm, such as about 10 mm. 
     As previously discussed, it is currently believed that high convective drag forces may impede migration of fresh reactants to the center of the rotating substrate. Embodiments disclosed herein address this challenge with increased gas flow rates (relative to the rotational spin rate of the substrate) and with improved gas flow directionality. For example, as illustrated in  FIGS.  3 A- 3 D , the configuration of the plurality of nozzles formed in the supply face of the injection module may facilitate migration of fresh reactants towards the center of the rotating substrate, crossing the rotational convective drag forces. 
     The number, size, pitch, and planarity of nozzles  306  is not to be limited by that which is shown in the Figures. In one example, the number of the nozzles  306  formed in the supply face  308  may differ from the number shown in  FIG.  3 A . For instance, 3, 4 or 5 nozzles  306  may be formed in the supply face  308 . In one example, the size of each of the nozzles  306  formed in the supply face  308  may differ. For instance, each of the nozzles may have a diameter between 20 mils and 100 mils, such as about 30 mils or 80 mils. In one example, each of the nozzles  306  may have a different size, pitch, and planarity. 
       FIG.  3 B  illustrates an injection module  310  having more than one injection zone. The injection module  310  has two body portions  312   a - b  that are separated from each other by a vertical partition  313 . As shown in  FIG.  3 B , the vertical partition  313  is perpendicular to the X-Z plane. The vertical partition  313  is at or near a horizontal center (measured in the Y-direction) between the two body portions  312   a - b . The injection module  310  has two separate and independent gas inlets  314   a - b . Alternatively, in some embodiments, multiple body portions (e.g.  312   a - b ) may be couple with a single gas inlet. As illustrated, a first gas inlet  314   a  is coupled to the first body portion  312   a , and a second gas inlet  314   b  is coupled to the second body portion  312   b . Similar to  FIG.  3 A , a plurality of nozzles  316   a - b  are formed in a corresponding supply face  318   a - b  of each body portion  312   a - b . However, in contrast to  FIG.  3 A , first and second groups of nozzles  316   a - b  of each body portion  312   a - b  are fluidly coupled to only the corresponding gas inlet  314   a - b . In  FIG.  3 B , spacing between the pair of nozzles proximate the partition  313  is greater compared to spacing between other adjacent pairs of nozzles. In some other examples, spacing between each adjacent pair of nozzles is equal for all nozzles, or in other words, the nozzles have uniform pitch. 
     In some embodiments, the two separate body portions  312   a - b , the gas inlets  314   a - b , and the nozzles  316   a - b  are configured to be coplanar (i.e., in the same plane, here the X-Y plane) with the second conduit  202  (shown in  FIG.  2 A ). In some other embodiments, one or more of the body portions  312   a - b , the gas inlets  314   a - b , the nozzles  316   a - b , or combinations thereof are not aligned in the same plane with the second conduit  202 . 
     In some other examples, the injection module  310  may have more than two injection zones including more than two body portions, separate gas inlets corresponding to each body portion, and a partition between each adjacent body portion. In some examples, the body portions may have the same or different widths. In some examples, the number of separate gas inlets may be the same, greater, or less than the number of injection zones or separate body portions. In some examples, the injection module  310  may have two to seven separate injection zones, such as two, three, four, five, six, or seven separate injection zones. In some examples, the first and second groups of nozzles  316   a - b  may have one to seven individual nozzles, such as one, two, three, four, five, six, or seven individual nozzles. Gas flow through each injection zone may be controlled independently (e.g., using a proportional control valve on each gas inlet  314   a - b ). Independent control of gas flow through each injection zone may enable better control of gas flow rate, distribution, and/or directionality within the process chamber  110 , thereby improving gas flux and reaction uniformity across the surface of the substrate  132 . 
       FIG.  3 C  illustrates an injection module  320  having a low flow region, or “void area.” The injection module  320  is similar to  FIG.  3 A , having a body  322 , a single gas inlet  324  coupled to the body  322 , and a plurality of nozzles  326  formed in a supply face  328  of the body  322 . However, in contrast to  FIG.  3 A , the supply face  328  has a void area  321  (inside the dashed line) with a larger spacing between proximate adjacent nozzles, compared to spacing between other adjacent pairs of nozzles. In some examples, the spacing between proximate adjacent nozzles in the void area  321  may be about 2× to about 10× greater than spacing between other adjacent pairs of nozzles, such as about 5×greater, as shown. In some other examples, the supply face  328  may have two or more separate void areas between groups of nozzles with closer spacing. 
     As shown in  FIG.  3 C , the void area  321  is located at or near a horizontal center (measured in the Y-direction) of the supply face  328 . Also as illustrated, the void area  321  is overlapping (e.g., aligned with) the gas inlet  324 . When the void area  321  overlaps the gas inlet  324 , as shown in  FIG.  3 C , distribution of gas flow through the remaining nozzles  326  is improved. In other words, by blocking straight-line gas flow through one or more nozzles that would otherwise be overlapping the gas inlet  324 , gas flow distribution through the remaining nozzles  326  is more uniform. In some other embodiments, baffles or a diffuser plate may be disposed in the body  322  to improve gas flow distribution and/or increase gas flow uniformity through the nozzles. 
     Another advantage of including the void area  321  proximate the horizontal center of the supply face  328  is to direct relatively higher gas flow towards a radial edge of the substrate  132 , compared to a radial center of the substrate  132 , for example, when higher gas flow at the radial edge is desired. In some other examples, the void area  321  may be located proximate a horizontal edge of the supply face  328 , for example, when higher gas flow at the radial center of the substrate  132  is desired. 
       FIG.  3 D  illustrates an injection module  330  having nozzles arrayed in two different directions on the supply face  328  (i.e., along the Y-Z plane). Similar to  FIG.  3 B , the injection module  330  has two body portions  332   a - b  that are separated from each other by a vertical partition  333 . The vertical partition  333  is at or near a horizontal center (measured in the Y-direction) between the two separate body portions  332   a - b . The injection module  330  has two separate and independent gas inlets  334   a - b . A first gas inlet  334   a  is coupled to the first body portion  332   a , and a second gas inlet  334   b  is coupled to the second body portion  332   b . Similar to  FIG.  3 B , a plurality of nozzles are formed in a corresponding supply face  338   a - b  of each body portion  332   a - b  facing the interior of the process chamber  110 . However, in contrast to  FIG.  3 B , the plurality of nozzles are arrayed in both the vertical (Z) and horizontal (Y) directions on the supply face. A first group of nozzles of the first body portion  332   a  has an upper row  336   a  and a lower row  336   a ′. Likewise, a second group of nozzles of the second body portion  332   b  has an upper row  336   b  and a lower row  336   b ′. The stacked arrangement of nozzles increases gas flow distribution in the vertical (Z) direction. In some examples, each group of nozzles may have two to nine rows, such as two, three, four, five, six, seven, eight, or nine rows. In some examples, each group of nozzles may have the same or different numbers of rows. In some examples, the nozzles in  FIGS.  3 A- 3 D  may have uniform or non-uniform pitch or spacing. In some examples, the number of nozzles in each body portion may be the same or different. In some examples, the nozzles may be the same or different sizes. 
     In some examples, either of the injection modules with multiple gas inlets (shown in  FIGS.  3 B and  3 D ) may have a void area similar to  FIG.  3 C  to selectively control gas flow in relation to the substrate. 
       FIGS.  4 A- 4 D  are cross-sectional views of various injection modules  400   a - d  that may be used in the process chamber  110 , according to examples of the present disclosure, which may be combined with other embodiments disclosed herein.  FIGS.  4 A- 4 D  illustrate a body  402 , a single gas inlet  404  coupled to the body  402 , and a plurality of nozzles  406  formed in a supply face  408  of the body  402 .  FIG.  4 A  is a top cross-sectional view of an injection module  400   a . As shown in  FIG.  4 A , the nozzles  406   a  are oriented perpendicular to the supply face  408  (also referred to as “straight nozzles”). The nozzles  406   a  are parallel to each other in the X direction. 
       FIG.  4 B  is a top cross-sectional view of an injection module  400   b . As shown in  FIG.  4 B , the nozzles  406   b  are oriented at an angle other than perpendicular to the supply face  408  and to the X direction (also referred to as “angled nozzles”). In  FIG.  4 B , the nozzles  406   b  are configured to be angled towards a counterclockwise direction (−Y direction) in relation to the substrate  132  ( FIG.  2 B ). In some other examples, the nozzles  406   b  may be configured to be angled in a clockwise direction (+Y direction) in relation to the substrate  132  ( FIG.  2 B ). In some examples, the angle of the nozzles  406   b  measured from perpendicular to the supply face  408  in the +Y or −Y direction may be within a range of about 0° to about 80° in either direction, such as about 0° to about 60°, such as about 0° to about 45°, such as about 0° to about 30°, such as about 0° to about 15°, or about 15° to about 75°, such as about 30° to about 60°, such as about 30°, about 45°, or about 60° in either direction. In  FIG.  4 B , the angled nozzles  406   b  are parallel to each other, thus having the same angle with the supply face  408 . In some other embodiments, the angled nozzles  406   b  may be oriented at different angles from each other. The remaining nozzles  406   a  are oriented perpendicular to the supply face  408 , similar to  FIG.  4 A . In some other embodiments, the straight and angled nozzles may be combined in various arrangements depending on the application. For example, the straight and angled nozzles may be arranged in a pattern, such as an alternating pattern. 
       FIG.  4 C  is a side cross-sectional view of an injection module  400   c  with nozzles arrayed in two different directions on the supply face (e.g., as shown in  FIG.  3 D ). As shown in  FIG.  4 C , the nozzles  406   c  are straight nozzles, being oriented perpendicular to the supply face  408 . The nozzles  406   c  are parallel to each other in the X direction. 
       FIG.  4 D  is a side cross-sectional view of an injection module  400   d  with nozzles arrayed in two different directions on the supply face (e.g., as shown in  FIG.  3 D ). As shown in  FIG.  4 D , at least some of the nozzles are angled in relation to the supply face  408  and to the X direction (also referred to as “angled nozzles”). In other words, the nozzles are inclined relative to the horizontal (X-Y) plane. The nozzle  406   d  is configured to be angled upwards (+Z direction) away from the substrate  132  ( FIG.  2 B ). The nozzle  406   e  is configured to be angled downwards (−Z direction) towards the substrate  132  ( FIG.  2 B ). In some examples, the angle of the nozzles  406   d - e  measured from perpendicular to the supply face  408  in the +Z or −Z direction may be within a range of about 0° to 80° in either direction, such as about 0° to about 60°, such as about 0° to about 45°, such as about 0° to about 30°, such as about 0° to about 15°, or about 15° to about 75°, such as about 30° to about 60°, such as about 30°, about 45°, or about 60° in either direction. The remaining nozzles  406   c  are oriented perpendicular to the supply face  408 , similar to  FIG.  4 C . In some other embodiments, the straight and angled nozzles may be combined in various arrangements depending on the application. For example, the straight and angled nozzles may be arranged in a pattern, such as an alternating pattern. 
       FIG.  4 E  is an isometric front view of an injection module  400   e  with a plurality of nozzles  406   f - k  formed in a corresponding supply face  418   f - k  of each body portion  412   f - k . As shown in  FIG.  4 E , the number, size, pitch, and planarity of nozzles  406   f - k  on each corresponding supply face  418   f - k  may be the same or different. In some embodiments, the size, pitch, and/or planarity of nozzles  406   f - k  on each corresponding supply face  418   f - k  may be the same or different than the adjacent nozzle  406   f - k . The number of gas inlets  444   a - e  may be the same as, more than, or less than the number of body portions  412   f - k . In some embodiments, multiple body portions  412   f - k  may share a single gas inlet  444   a - e . In some embodiments, which can be combined with other embodiments described herein, a single body portion  412   f - k  may have multiple gas inlets  444   a - e . Although each of the nozzles  406   f - k  are shown perpendicular to the corresponding supply face  418   f - k , it is contemplated that, in some embodiments, one or more of the nozzles  406   f - k  are angled with respect to the corresponding supply face  418   f - k . In the embodiment where one or more of the nozzles  406   f - k  are angled with respect to the corresponding supply face  418   f - k , the nozzles  406   f - k  may be pointed in at least two or more directions. 
     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, and the scope thereof is determined by the claims that follow.