Plasma chamber backing plate improvement

Abstract

A process chamber for processing a substrate is provided. The process chamber includes: a chamber body disposed around an interior volume; a substrate support in the interior volume; a showerhead positioned over the substrate support; and a backing plate positioned over the showerhead. A plenum is formed between the showerhead and the backing plate, the backing plate including a gas inlet, a first gas outlet positioned at a center of the backing plate, and a first plurality of additional gas outlets fluidly coupled to the gas inlet by a plurality of internal channels of the backing plate.

Description

PLASMA CHAMBER BACKING PLATE IMPROVEMENTBACKGROUNDField

[0001] Embodiments of the present disclosure generally relate to improved backing plates for use in process chambers, such as semiconductor plasma processing chambers.Description of the Related Art

[0002] Plasma processing can be used to perform many processes on substrates, such as semiconductor substrates. Plasma enhanced chemical vapor deposition (PECVD) can be used to deposit layers over substrates. During PECVD processes a plasma can be formed from one or more precursor gases provided to an interior volume of a process chamber over the substrate. Although the PECVD processes can be used to form a variety of layers on various substrates, the PECVD processes also result in undesired deposits inside the process chamber. These undesired can eventually affect processes being performed, so the interior of the process chambers are cleaned to remove the deposits.

[0003] One method to clean the interior of the process chambers uses a remote plasma source to supply a plasma of a cleaning agent, such as nitrogen trifluoride (NF3). Cleaning with plasma cleaning agents, such as NF3, can be expensive and can also eventually lead to damaging components inside the process chamber due the aggressive nature of plasma species in the cleaning plasma, such as fluoride ions and radicals. Additionally, the cleaning of the interior of the process chamber can often be non-uniform. For example, in some process chambers, a remote plasma can often clean the center of the process chamber at faster rate than the outer portions of the process chamber near the process chamber side walls.

[0004] Thus, there is an ongoing need to reduce the operating costs associated with cleaning the interior of process chambers while also achieving a high level ofuniform cleanliness during these cleaning procedures without damaging components inside the process chamber.SUMMARY

[0005] Embodiments of the present disclosure generally relate to improved backing plates for use in process chambers, such as semiconductor plasma processing chambers.

[0006] In one embodiment, a process chamber for processing a substrate is provided. The process chamber includes: a chamber body disposed around an interior volume; a substrate support in the interior volume; a showerhead positioned over the substrate support; and a backing plate positioned over the showerhead, wherein a plenum is formed between the showerhead and the backing plate, the backing plate including a gas inlet, a first gas outlet positioned at a center of the backing plate, and a first plurality of additional gas outlets fluidly coupled to the gas inlet by a plurality of internal channels of the backing plate.

[0007] In another embodiment, a processing system is provided comprising: a radio frequency power source; a remote plasma source; and a process chamber for processing a substrate comprising: a chamber body disposed around an interior volume; a substrate support in the interior volume; a showerhead positioned over the substrate support; and a backing plate positioned over the showerhead, the backing plate including a gas inlet, a first gas outlet positioned at a center of the backing plate, and a first plurality of additional gas outlets fluidly coupled to the gas inlet by a plurality of internal channels of the backing plate, wherein the radio frequency power source is connected to the backing plate, a plenum is formed between the showerhead and the backing plate, and the remote plasma source is fluidly connected to the inlet of the backing plate.

[0008] In another embodiment, a processing system is provided comprising: a remote plasma source; a cleaning gas source fluidly coupled with the remote plasma source; a process chamber for processing a substrate comprising: a chamber body disposed around an interior volume; a substrate support in the interior volume; a showerhead positioned over the substrate support; and a backing plate positioned over the showerhead, the backing plate including a gas inlet, a first gas outletpositioned at a center of the backing plate, and a first plurality of additional gas outlets fluidly coupled to the gas inlet by a plurality of internal channels of the backing plate, wherein each gas outlet of the first plurality of additional gas outlets is positioned at a first distance from the center of the backing plate, the radio frequency power source is connected to the backing plate, a plenum is formed between the showerhead and the backing plate, and the remote plasma source is fluidly connected to the inlet of the backing plate; and a controller configured to: direct cleaning gas from the cleaning gas source to the remote plasma source; energize the remote plasma source to form a plasma of the cleaning gases directed to the remote plasma source; and direct the plasma generated in the remote plasma source through the first plurality of additional gas outlets of the backing plate and into the plenum formed between the showerhead and the backing plate.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] 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 its scope, and may admit to other equally effective embodiments.

[0010] Figure 1 illustrates a schematic side cross-sectional view of a processing system, according to one embodiment.

[0011] Figure 2A is a semi-transparent bottom view of the backing plate from Figure 1 , according to one embodiment.

[0012] Figure 2B is a semi-transparent bottom view of the first gas outlet from Figure 2A, according to one embodiment.

[0013] Figure 2C shows a side view of the first passageway from Figure 2B, according to one embodiment.

[0014] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It iscontemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.DETAILED DESCRIPTION

[0015] Embodiments of the present disclosure generally relate to improved backing plates for use in process chambers, such as semiconductor plasma processing chambers. The backing plates disclosed herein include a plurality of internal channels and a plurality of outlets fluidly coupled to the internal channels that can be used to disperse gas and / or plasma over a wider area compared to conventional backing plates. The gas and / or plasma is dispersed by the backing plate into a plenum that is formed between the backing plate and a showerhead of the process chamber. The showerhead then distributes the gas and / or plasma provided to the plenum to the process volume between the substrate support and the showerhead.

[0016] The internal channels and the additional outlets of the backing plates disclosed herein can be used to increase the cleaning rate of components in the outer regions of the interior volume of the process chamber, such as components near the sidewalls of the process chamber. Increasing the cleaning rate for components in the outer regions of the interior volume is useful because otherwise similar cleaning processes performed with process chambers having conventional backing plates results in the components in the outer regions of the interior volume being cleaned at significantly slower rates. With the backing plates disclosed herein, components in the outer regions of the interior volume can be cleaned at rates that are uniform with the rates at which components in the inner portions of the interior volume are cleaned. Because the different portions of the interior volume are cleaned at similar rates, operating costs can be reduced since less cleaning gases and / or cleaning plasma is used to clean the chamber interior to a sufficient level of cleanliness. Furthermore, cleaning the components in the inner portions and outer portions of the interior volume at similar rates prevents damage to the components in the inner portions caused by the over-exposure of these components to excessive cleaning plasma when the interior volume is cleaned using a conventional backing plate.

[0017] Figure 1 illustrates a schematic side cross-sectional view of a processing system 100, according to one embodiment. The processing system 100 includes a process chamber 101 , a process gas source 141 , a cleaning gas source 142, an RF power source 145, a remote plasma source 146, and a controller 185.

[0018] The process chamber 101 includes a chamber body 102 and a lid 107 positioned over (e.g., directly on) the chamber body 102. The chamber body 102 and lid 107 are disposed around an interior volume 110 of the process chamber 101 . The chamber body 102 includes one or more sidewalls 103 and a bottom 104. The process chamber 101 further includes a slit valve 109 positioned in an opening in one of the sidewalls 103 of the chamber body 102. The slit valve 109 can be configured to open to allow the transfer of substrates 50 into and out of the interior volume 110 of the process chamber 101 .

[0019] The process chamber 101 further includes a backing plate 200, a showerhead 120, and a substrate support assembly 130. The substrate support assembly 130 includes a substrate support 135 for supporting a substrate 50 during processing. The portion of the interior volume 110 between the showerhead 120 and the substrate support 135 is a process volume 111.

[0020] The substrate support assembly 130 further includes a shaft 136 coupled to the substrate support 135 and an actuator 138. The actuator 138 can be configured to move the shaft 136 to raise and lower the substrate support 135. In some embodiments, the actuator 138 can also be configured to rotate the shaft 136 and substrate support 135 during processing. The substrate support assembly 130 can additionally include a first plurality of lift pins 131 and a second plurality of lift pins 132. The different length of the lift pins 131 , 132 in the Z-direction can reduce bowing of the substrate 50 when the substrate 50 is supported by the lift pins 131 , 132.

[0021] The one or more sidewalls 103 can include an inner ledge 106 that extends inwardly towards the substrate support 135. The inner ledge 106 can extend around the entire interior volume 110 (e.g., for 360 degrees). The process chamber 101 can further include a first liner 161 positioned on top of the inner ledge 106 and a second liner 162 covering the portions of the inner surfaces of the one or more sidewalls 103 that are above the inner ledge 106 and below the isolators 126 that are furtherdescribed below. The liners 161 , 162 can be formed of a ceramic material, such as aluminum oxide (AI2O3). In some embodiments, fasteners 108 can be used to secure the second liners 162 to the one or more sidewalls 103.

[0022] The showerhead 120 is positioned over the substrate support 135. The backing plate 200 is positioned over the showerhead 120. A plenum 112 is formed between the showerhead 120 and the backing plate 200. The showerhead 120 includes a plurality of passages 122 to distribute gas and / or plasma into the process volume 111 over the substrate support 135. The process chamber 101 further includes a conduit 147 that is fluidly coupled to the process gas source 141 and the remote plasma source 146. The conduit 147 is further coupled to a gas inlet 201 of the backing plate 200, so that gases and / or plasma can be distributed through (1 ) the backing plate 200, (2) the showerhead 120, and (3) into the process volume 111.

[0023] The backing plate 200 includes a body 204 formed of an electrically conductive material, such as aluminum. The backing plate 200 further includes a gas inlet 201 , a main gas outlet 202, a central cavity 203, a plurality of internal channels 205, a first plurality of additional gas outlets 210, and a second plurality of additional gas outlets 220. The main gas outlet 202 is positioned at a center 200C of the backing plate 200. The first plurality of additional gas outlets 210 and the second plurality of additional gas outlets 220 are each coupled to the gas inlet 201 by the central cavity 203 and the internal channels 205. The main gas outlet 202, the first plurality of additional gas outlets 210 and the second plurality of additional gas outlets 220 are each configured to discharge gas and / or plasma into the plenum 112. The showerhead 120 then distributes the gas and / or plasma from the plenum 112 into the process volume 111 below the showerhead 120.

[0024] The body 204 of the backing plate 200 can include a plurality of sidewalls 207. In some embodiments, the plurality of internal channels 205 can be gun-drilled through the body 204 from one of the sidewalls 207 to the central cavity 203. Furthermore, in some embodiments a plug 208 can be positioned in the opening of the internal channels 205 at the sidewall 207 as shown or at another location, for example immediately downstream of the gas outlet 220 on that internal channel 205. The plug 208 can prevent plasma and / or gases in the internal channels 205 fromdischarging from the backing plate 200 at locations other than the intended gas outlets 202, 210, 220.

[0025] Each of the internal channels 205 can have a cross-section (e.g., diameter) that is relatively narrow while having a length that is substantially longer. For example, in some embodiments, the internal channels 205 can each have a length that is at least 25 times or at least 50 times greater than the cross-sectional dimension (e.g., diameter) of the channel 205. In one embodiment, each channel 205 has a diameter from about 0.5 inches to about 2.0 inches, such as about 1.0 inch while having a length from about 20 inches to about 100 inches, such as about 40 inches. The configuration of the internal channels 205 extending outward from the central cavity 203 can resemble narrow spokes extending outward from the center of a wheel.

[0026] Gun-drilling the internal channels 205 allows the channels 205 to be formed to have a long and narrow profile similar to spokes of a wheel. This long and narrow profile of the internal channels 205 allows each of the channels 205 to be angularly spaced apart from the other channels 205 by a substantial angular distance. For example, each of the eight internal channels 205 shown in Figure 2A are spaced apart from a next closest internal channel by about 40 degrees to about 45 degrees. The plurality of additional gas outlets 210, 220 can be spaced apart from each other by similar angular distances. The long and narrow profile of the internal channels 205 and relatively small footprint of the additional gas outlets 210, 220 allows for additional cleaning plasma to be provided to the outer portions of the interior volume 110 during cleaning to improve the cleaning rate of the outer portions of the interior volume 110 while not significantly altering the spatial distribution of process gases over the substrate during processes, such as depositions. Other designs for distributing gases and / or plasma to outer regions of the interior of the backing plate with one or more large internal plenums, such as a single large cavity spanning across most of the interior of the backing plate or two or more ring-shaped plenums may improve the cleaning rate of outer portions of the interior volume 110, but would result in directing too much process gas to outer regions of the process volume 111 during processing (e.g., depositions), which would diminish the process results (e.g., deposition rate and center to edge thickness uniformity) of the process (e.g., deposition) performed on the substrate. Having each of the internal channels 205 originate from the central cavity203 can assist in achieving the balance of flow through the backing plate that improves the cleaning rate of the outer regions of the interior volume 110 without significantly diminishing the process results of the process performed on the substrate.

[0027] The RF power source 145 can be electrically coupled to the backing plate 200. The process chamber 101 can further include one or more supports 125. The supports 125 can be formed of an electrically conductive material to electrically couple the RF energy provided to the backing plate 200 to the showerhead 120, so that the RF energy applied to the showerhead 120 can be used to generate a plasma in the process volume 111 during processing.

[0028] The chamber body 102 and lid 107 can be electrically connected to ground. In some embodiments, the substrate support 135 can also be electrically coupled to ground, so that a plasma can be generated in the process volume 111 with the RF energy provided to the showerhead 120 using the substrate support 135 as part of the return path to ground. In some embodiments, the substrate support 135 can include an electrode (not shown) that is electrically connected with the chamber body 102 as part of the path of to ground. The one or more sidewalls 103 of the chamber body 102 can include one or more inner ledges 105. The process chamber 101 can include one or more isolators 126 positioned on the one or more inner ledges 105 of the one or more sidewalls 103. The backing plate 200 can be positioned on the one or more isolators 126. The one or more isolators 126 can be formed of an electrically insulating material to electrically isolate the backing plate 200 from the chamber body 102. In one embodiment, the one or more isolators 126 are formed of a dielectric material.

[0029] One or more cleaning gases (e.g., NF3) can be provided to the remote plasma source 146, so that the remote plasma source 146 can generate a plasma of the one or more cleaning gases. The remote plasma source 146 can include an RF power source or other energy source for generating the plasma in the remote plasma source 146. The plasma generated by the remote plasma source 146 can then be provided to the process volume 111 through the backing plate 200 and the showerhead 120. Process gases from the process gas source 141 can be providedto the process volume 111 along a similar gas flow path as the cleaning plasma through the conduit 147, the backing plate 200, and the showerhead 120.

[0030] The processing system 100 also includes the controller 185 for controlling processes performed by the processing system 100. The controller 185 can be any type of controller used in an industrial setting, such as a programmable logic controller (PLC). The controller 185 includes a processor 187, a memory 186, and input / output (I / O) circuits 188. The controller 185 can further include one or more of the following components (not shown), such as one or more power supplies, clocks, communication components (e.g., network interface card), and user interfaces typically found in controllers for semiconductor equipment.

[0031] The memory 186 can include non-transitory memory. The non-transitory memory can be used to store the programs and settings described below. The memory 186 can include one or more readily available types of memory, such as read only memory (ROM) (e.g., electrically erasable programmable read-only memory (EEPROM), flash memory, floppy disk, hard disk, or random access memory (RAM) (e.g., non-volatile random access memory (NVRAM).

[0032] The processor 187 is configured to execute various programs stored in the memory 186, such as deposition processes and purging processes. During execution of these programs, the controller 185 can communicate to I / O devices through the I / O circuits 188. For example, during execution of these programs and communication through the I / O circuits 188, the controller 185 can control outputs, such as energizing the RF power source 145, changing the position of valves (not shown) to send process gases or cleaning plasma to the interior volume 110 of the process chamber 101 . The memory 186 can further include various operational settings used to control the processing system 100. For example, the settings can include durations for how long the different valves remain open or closed during different depositions and cleaning processes.

[0033] Generally, conventional backing plates for plasma process chambers include a central opening, such as the gas outlet 202, but do not include the additional pluralities of gas outlets 210, 220. Due to this arrangement, cleaning procedures performed with conventional backing plates often result in cleaning components in thecenter of the interior volume 110 (e.g., the center of the substrate support 135) faster than components in the outer portions of the interior volume 110, such as exposed portions of the sidewalls 103, the liners 161 , 162, and the support 125. These non- uniform cleaning rates results in (1 ) using more cleaning gases than would be used if the cleaning rates were more uniform, and (2) eventually damaging the components in the center of the interior volume 110 as these components are exposed to significant amounts of cleaning plasma after these components are cleaned to a sufficient level, which shortens the useful life of these components.

[0034] By using the backing plate 200, additional cleaning plasma is provided through the additional gas outlets 210, 220, and the components in the outer portions of the interior volume 110 can be cleaned at a higher rate. Cleaning these components in the outer portions of the interior volume 110 allows the cleaning rates of the inner portions of the interior volume 110 to be more uniform with the cleaning rates of the outer portions of the interior volume 110. With this improvement in cleaning uniformity, the components in the inner portions and the outer portions of the interior volume 110 can reach a sufficient level of cleanliness around the same time during a cleaning procedure, which prevents the significant over-exposure of the components in the inner portion of the interior volume 110 to the aggressive plasma of the cleaning agent that occurs when the cleaning rates are non-uniform. Thus, the backing plates disclosed herein allow cleaning procedures to be completed more quickly with less material cost (e.g., less NF3 used) while also preventing the reduction of useful life of components in the inner portion of the interior volume 110 due to over- exposure to plasma during non-uniform cleaning procedures performed with conventional backing plates.

[0035] Figure 2A is a semi-transparent bottom view of the backing plate 200 from Figure 1 , according to one embodiment. The view is described as semi-transparent as some internal components that are shown in Figure 2A, such as the internal channels 205, would not actually be visible in the bottom view of the backing plate 200.

[0036] The backing plate 200 includes four sidewalls 207I-2074. The backing plate 200 includes the plurality of internal channels 205, the first plurality of additional gas outlets 210, and the second plurality of additional gas outlets 220. The plurality ofinternal channels 205 includes eight different internal channels 205i-205s with each internal channel 205 extending from an opening in one of the sidewalls 207 to the center 200C of the backing plate 200. Each internal channel 205 can extend along a different angular orientation relative to the center 200C of the backing plate 200. Each internal channel 205 can be fluidly coupled with the central cavity 203 (see Figure 1 ), so that plasma and / or gas provided to the gas inlet 201 can be distributed through the central cavity 203 and the internal channels 205 to each of the pluralities of additional gas outlets 210, 220.

[0037] The first plurality of additional gas outlets 210 can include eight gas outlets 210i -21 Os with each gas outlet 210 fluidly coupled with a different one of the internal channels 205i-205s. Similarly, the second plurality of additional gas outlets 220 can include eight gas outlets 220i-220s with each gas outlet 220 fluidly coupled with a different one of the internal channels 205i-205s. Each gas outlet 210 in the first plurality of additional gas outlets 210 is located at a first distance D1 from the center 200C of the backing plate 200. Each gas outlet 220 in the second plurality of additional gas outlets 220 is located at a second distance D2 from the center 200C of the backing plate 200. The second distance D2 is longer than the first distance D1. The distances D1 , D2 shown in Figure 2A are only exemplary distances and the locations of gas outlets 210, 220 can be positioned at any distance from the center 200C of the backing plate 200 including locations right near the center 200C, locations at or bordering one of the sidewalls 207, and locations anywhere in between the center 200C or sidewalls 207. Furthermore, some embodiments can include gas outlets, such as gas outlets 210, 220, at three or more distances from the center of the backing plate.

[0038] Each gas outlet 210 is located at a different angular location relative to the center 200C of the of the backing plate 200 when compared to the other gas outlets 210 in the first plurality of gas outlets 210. Similarly, each gas outlet 220 is located at a different angular location relative to the center 200C of the of the backing plate 200 when compared to the other gas outlets 220 in the second plurality of gas outlets 220. In Figure 2A, each gas outlet 210 is at a same angular location relative to the center 200C as a corresponding one of the gas outlets 220. However, in some embodiments, the gas outlets 210, 220 can be staggered and each gas outlet 210 can be positionedat angular location relative to the center 200C that is different from the angular location relative to the center 200C for some or all of the gas outlets 220. In embodiments in which the angular locations of the gas outlets 210 are staggered from one or more of the angular locations of the gas outlets 220, the backing plate can include additional internal channels 205 for these additional gas outlet locations. In embodiments including gas outlets located at three or more different distances from the center of the backing plate, the angular locations of the gas outlets at the different distances may be shared or staggered with other gas outlets of the three or more gas outlets.

[0039] Figure 2B is a semi-transparent bottom view of the first gas outlet 210i from Figure 2A, according to one embodiment. The view is described as semi-transparent as some internal components that are shown in Figure 2B, such as those components indicated in dashed lines, would not actually be visible in the bottom view of the first gas outlet 210i . The bottom view of the other gas outlets 210 can be the same as the view shown in Figure 2B in some embodiments. Similarly, the bottom view of the other gas outlets 220 in the second plurality of gas outlets 220 can also be the same as the view shown in Figure 2B in some embodiments.

[0040] The first gas outlet 210i includes a body 211 , such as a metallic body. The body 211 of the first gas outlet 210i includes four gas passageways 217i -2174. Each passageway 217 is symmetrically arranged at a different angular location about a central vertical axis C extending through the center of the first gas outlet 210i . Other embodiments can include more or fewer passageways 217. Additionally, other embodiments can include passageways at different distances from the central vertical axis C and oriented at different angles compared to the passageways 217 shown in Figure 2B.

[0041] Each gas passageway 217 includes a corresponding inlet opening 215 and a corresponding outlet opening 216. Each inlet opening 215 can be fluidly coupled to one of the internal channels 205 (see Figure 2A) extending through the interior of the backing plate 200. Each passageway 217 can extend outwardly as the passageway 217 extends downwardly from the inlet opening 215 to the outlet opening 216. The inlet opening 215 of each passageway 217 can be located closer to the central vertical axis C than the outlet opening 216 is from the central vertical axis C.

[0042] Figure 2C shows a side view of the first passageway 217i from Figure 2B, according to one embodiment. As shown in Figure 2C, the inlet opening 215i is located closer to the central vertical axis C than the outlet opening 2161 is to the central vertical axis C. The passageway 217i is oriented at angle 0 relative to a vertical direction V. The angle 0 can be from about 10 degrees to about 50 degrees, such as about 30 degrees relative to the vertical direction V. This orientation angling the passageway 217i outwardly away from the central vertical axis C as the passageway 217i extends downward helps disperse the gas and / or plasma flowing through the passageway 217i away from gas outlet 210i in the X and Y-directions as the gas and / or plasma exits the outlet openings 216 of the gas outlet 210i into the plenum 112.

[0043] 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.

Claims

What is claimed is:1 . A process chamber for processing a substrate comprising: a chamber body disposed around an interior volume; a substrate support in the interior volume; a showerhead positioned over the substrate support; and a backing plate positioned over the showerhead, wherein a plenum is formed between the showerhead and the backing plate, the backing plate including a gas inlet, a first gas outlet positioned at a center of the backing plate, and a first plurality of additional gas outlets fluidly coupled to the gas inlet by a plurality of internal channels of the backing plate.

2. The process chamber of claim 1 , wherein each gas outlet of the first plurality of additional gas outlets is positioned at a first distance from the center of the backing plate.

3. The process chamber of claim 2, wherein each gas outlet of the first plurality of additional gas outlets is positioned at a different angular location relative to the center of the backing plate.

4. The process chamber of claim 1 , wherein each of the first plurality of additional gas outlets includes a plurality of gas passageways fluidly coupled to the plenum.

5. The process chamber of claim 4, wherein each of the gas passageways included in each of the first plurality of additional gas outlets is oriented at an angle from about 10 degrees to about 50 degrees relative to a vertical direction.

6. The process chamber of claim 2, wherein the backing plate further comprises a second plurality of additional gas outlets fluidly coupled to the inlet of the backing plate, and each additional gas outlet of the second plurality of additional gas outlets located at a second distance from the center of the backing plate.

7. The process chamber of claim 6, wherein each gas outlet of the second plurality of additional gas outlets is positioned at a different angular location relative to the center of the backing plate.

8. The process chamber of claim 6, wherein each of the second plurality of additional gas outlets includes a plurality of gas passageways fluidly coupled to the plenum.

9. The process chamber of claim 8, wherein each of the gas passageways included in each of the second plurality of additional gas outlets is oriented at an angle from about 10 degrees to about 50 degrees relative to a vertical direction.

10. A processing system comprising: a radio frequency power source; a remote plasma source; and a process chamber for processing a substrate comprising: a chamber body disposed around an interior volume; a substrate support in the interior volume; a showerhead positioned over the substrate support; and a backing plate positioned over the showerhead, the backing plate including a gas inlet, a first gas outlet positioned at a center of the backing plate, and a first plurality of additional gas outlets fluidly coupled to the gas inlet by a plurality of internal channels of the backing plate, wherein the radio frequency power source is connected to the backing plate, a plenum is formed between the showerhead and the backing plate, and the remote plasma source is fluidly connected to the inlet of the backing plate.11 . The processing system of claim 10, wherein each gas outlet of the first plurality of additional gas outlets is positioned at a first distance from the center of the backing plate.

12. The processing system of claim 11 , wherein each gas outlet of the first plurality of additional gas outlets is positioned at a different angular location relative to the center of the backing plate.

13. The processing system of claim 10, wherein each of the first plurality of additional gas outlets includes a plurality of gas passageways fluidly coupled to the plenum.

14. The processing system of claim 13, wherein each of the gas passageways included in each of the first plurality of additional gas outlets is oriented at an angle from about 10 degrees to about 50 degrees relative to a vertical direction.

15. The processing system of claim 11 , wherein the backing plate further comprises a second plurality of additional gas outlets fluidly coupled to the inlet of the backing plate, and each additional gas outlet of the second plurality of additional gas outlets located at a second distance from the center of the backing plate.

16. The processing system of claim 15, wherein each gas outlet of the second plurality of additional gas outlets is positioned at a different angular location relative to the center of the backing plate.

17. The processing system of claim 15, wherein each of the second plurality of additional gas outlets includes a plurality of gas passageways fluidly coupled to the plenum.

18. The processing system of claim 17, wherein each of the gas passageways included in each of the second plurality of additional gas outlets is oriented at an angle from about 10 degrees to about 50 degrees relative to a vertical direction.

19. A processing system comprising: a remote plasma source; a cleaning gas source fluidly coupled with the remote plasma source;a process chamber for processing a substrate comprising: a chamber body disposed around an interior volume; a substrate support in the interior volume; a showerhead positioned over the substrate support; and a backing plate positioned over the showerhead, the backing plate including a gas inlet, a first gas outlet positioned at a center of the backing plate, and a first plurality of additional gas outlets fluidly coupled to the gas inlet by a plurality of internal channels of the backing plate, wherein each gas outlet of the first plurality of additional gas outlets is positioned at a first distance from the center of the backing plate, the radio frequency power source is connected to the backing plate, a plenum is formed between the showerhead and the backing plate, and the remote plasma source is fluidly connected to the inlet of the backing plate; and a controller configured to: direct cleaning gas from the cleaning gas source to the remote plasma source; energize the remote plasma source to form a plasma of the cleaning gases directed to the remote plasma source; and direct the plasma generated in the remote plasma source through the first plurality of additional gas outlets of the backing plate and into the plenum formed between the showerhead and the backing plate.

20. The processing system of claim 19, wherein the backing plate further comprises a second plurality of additional gas outlets fluidly coupled to the inlet of the backing plate, and each additional gas outlet of the second plurality of additional gas outlets located at a second distance from the center of the backing plate.

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