Chemical control features in wafer process equipment

Gas distribution assemblies are described including an annular body, an upper plate, and a lower plate. The upper plate may define a first plurality of apertures, and the lower plate may define a second and third plurality of apertures. The upper and lower plates may be coupled with one another and the annular body such that the first and second apertures produce channels through the gas distribution assemblies, and a volume is defined between the upper and lower plates.

TECHNICAL FIELD

The present technology relates to semiconductor processes and equipment. More specifically, the present technology relates to processing system plasma components.

BACKGROUND

Integrated circuits are made possible by processes which produce intricately patterned material layers on substrate surfaces. Producing patterned material on a substrate requires controlled methods for removal of exposed material. Chemical etching is used for a variety of purposes including transferring a pattern in photoresist into underlying layers, thinning layers, or thinning lateral dimensions of features already present on the surface. Often it is desirable to have an etch process that etches one material faster than another facilitating, for example, a pattern transfer process. Such an etch process is said to be selective to the first material. As a result of the diversity of materials, circuits, and processes, etch processes have been developed with a selectivity towards a variety of materials.

Dry etches produced in local plasmas formed within the substrate processing region can penetrate more constrained trenches and exhibit less deformation of delicate remaining structures. However, as integrated circuit technology continues to scale down in size, the equipment that delivers the precursors can impact the uniformity and quality of the precursors and plasma species used.

Thus, there is a need for improved system components that can be used in plasma environments effectively while providing suitable degradation profiles. These and other needs are addressed by the present technology.

SUMMARY

Gas distribution assemblies are described including an annular body, an upper plate, and a lower plate. The upper plate may define a first plurality of apertures, and the lower plate may define a second and third plurality of apertures. The upper and lower plates may be coupled with one another and the annular body such that the first and second apertures produce channels through the gas distribution assemblies, and a volume is defined between the upper and lower plates.

The assemblies may include an annular body having an inner annular wall located at an inner diameter, an outer annular wall located at an outer diameter, as well as an upper surface and a lower surface. The annular body may further include a first upper recess formed in the upper surface, a first lower recess formed in the lower surface at the inner annular wall, and a second lower recess formed in the lower surface below and radially outward of the first lower recess. The annular body may also define a first fluid channel in the upper surface that is located in the annular body radially inward of the first upper recess. The assemblies may include an upper plate coupled with the annular body at the first upper recess and covering the first fluid channel, and the upper plate may define a plurality of first apertures. The assemblies may also include a lower plate coupled with the annular body at the first lower recess and having a plurality of second apertures defined in the plate where the second apertures align with the first apertures defined in the upper plate. The lower plate may also define a plurality of third apertures located between the second apertures. The upper and lower plates may be coupled with one another such that the first and second apertures are aligned to form a channel through the upper and lower plates.

The upper and lower plates of the assemblies may be bonded together. The annular body of the assemblies may further define a second fluid channel in the upper surface that is located radially outward of the first fluid channel, and a plurality of ports may be defined in a portion of the annular body defining an outer wall of the first fluid channel and an inner wall of the second fluid channel. The second fluid channel may be located radially outward of the upper recess such that the second fluid channel is not covered by the upper plate. The annular body may define a second upper recess near the top of the second fluid channel in both the inner wall and an outer wall, and the gas distribution assembly may include an annular member positioned within the second upper recess so as to cover the second fluid channel. The upper recess may include a bottom portion that intersects the outer wall of the first fluid channel.

The assemblies may further include a pair of isolation channels, where one of the pair of isolation channels is defined in the upper surface of the annular body, and the other of the pair of isolation channels is defined in the lower surface of the annular body. The pair of isolation channels may be vertically aligned with one another. The second fluid channel may be located radially inward of the upper recess such that the second fluid channel is covered by the upper plate in embodiments. A portion of the upper plate may also extend into the second channel below a bottom of the upper recess. The plurality of ports may be angled upward from the second fluid channel to the first fluid channel such that the ports are fluidly accessible below the portion of the upper plate extending into the second channel. The isolation channels may be disposed in embodiments so that one of the pair of isolation channels is defined in the upper plate at a location radially inward from the upper recess, and the other of the pair of isolation channels is defined in the lower surface of the annular body so that the pair of isolation channels are vertically aligned with one another. The annular body may also define an annular temperature channel configured to receive a cooling fluid operable to maintain a temperature of the annular body. The temperature channel may also be configured to receive a heating element disposed within the channel and operable to maintain a temperature of the annular body.

Gas distribution assemblies are also described that may include an annular body. The annular body may include an inner annular wall located at an inner diameter, an outer annular wall located at an outer diameter, and an upper surface and a lower surface. An upper recess may be formed in the upper surface and a lower recess may be formed in the lower surface. A first fluid channel may be defined in the lower surface that is located in the annular body radially inward of the lower recess. The assemblies may also include an upper plate coupled with the annular body at the upper recess, where the upper plate defines a plurality of first apertures. The assemblies may also include a lower plate coupled with the annular body at the lower recess, and covering the first fluid channel. The lower plate may define a plurality of second apertures that align with the first apertures defined in the upper plate. The lower plate may further define a plurality of third apertures located between the second apertures. The upper and lower plates may be coupled with one another such that the first and second apertures are aligned to form a channel through the upper and lower plates.

The gas distribution assemblies may include a second fluid channel defined in the lower surface that is located in the annular body radially outward of the first fluid channel. A plurality of ports may be defined in a portion of the annular body defining an outer wall of the first fluid channel and an inner wall of the second fluid channel, and the plurality of ports may be configured to fluidly couple the second fluid channel with the first fluid channel. The second fluid channel may be located radially inward of the lower recess such that the second fluid channel may be covered by the lower plate, and where a portion of the lower plate extends into the second channel above a top of the lower recess. The plurality of ports may be angled downward from the second fluid channel to the first fluid channel such that the ports are fluidly accessible above the portion of the lower plate extending into the second channel. The first apertures may also have a conical shape of decreasing diameter as the first apertures extend through the upper plate. The second and third apertures may have a conical shape of increasing diameter as the second and third apertures extend through the lower plate. Each of the second and third apertures may also include at least three sections of different shape or diameter.

Gas distribution assemblies are also described having an annular body having an inner wall located at an inner diameter, an outer wall located at an outer diameter, an upper surface, and a lower surface. The assemblies may also include an upper plate coupled with the annular body, and the upper plate may define a plurality of first apertures. An intermediate plate may be coupled with the upper plate, and the intermediate plate may define a plurality of second and third apertures, where the second apertures align with the first apertures of the upper plate. The assemblies may also include a lower plate coupled with the annular body and the intermediate plate. The lower plate may define a plurality of fourth apertures that align with the first apertures of the upper plate and the second apertures of the intermediate plate to form a first set of fluid channels through the plates. The lower plate may also define a plurality of fifth apertures that align with the third apertures of the intermediate plate to form a second set of fluid channels through the intermediate and lower plates, where the second set of fluid channels are fluidly isolated from the first set of fluid channels. The lower plate may further define a sixth set of apertures that form a third set of fluid channels through the lower plate, where the third set of fluid channels are fluidly isolated from the first and second set of fluid channels.

The lower plate of the gas distribution assemblies may include an orientation of the fourth, fifth, and sixth apertures such that a majority of fourth apertures are each surrounded by at least four of the fifth apertures and four of the sixth apertures. The fifth apertures may be located around the fourth apertures with centers of the fifth apertures at about 90° intervals from one another about a center of the fourth apertures, and the sixth apertures may be located around the fourth apertures with centers of the sixth apertures at about 90° intervals from one another about the center of the fourth apertures and offset from the fifth apertures by about 45°. The fifth apertures may be located around the fourth apertures with centers of the fifth apertures at about 60° intervals from one another about a center of the fourth apertures, and where the sixth apertures are located around the fourth apertures with centers of the sixth apertures at about 60° intervals from one another about the center of the fourth apertures and offset from the fifth apertures by about 30°.

Such technology may provide numerous benefits over conventional systems and techniques. For example, leakage through the assembly may be minimized or avoided providing improved flow characteristics, which may lead to improved process uniformity. Additionally, multiple precursors may be delivered through the assembly while being maintained fluidly isolated from one another. These and other embodiments, along with many of their advantages and features, are described in more detail in conjunction with the below description and attached figures.

DETAILED DESCRIPTION

The present technology includes improved gas distribution assembly or showerhead designs for distributing processing gases to produce flow patterns for forming deposition layers on a semiconductor substrate of a more uniform height and/or etching deposited layers in a more uniform fashion. While conventional showerhead designs may simply provide pass-through distribution systems for processing and precursor gases, the presently described technology allows for improved control of the flow characteristics of gases as they are delivered to a substrate processing chamber. In so doing, deposition operations may produce more accurate film profiles during manufacturing operations.

Although some conventional gas distribution assemblies or showerheads may include multiple fluid channels covered by a plate, for example, such designs routinely suffer from gaps along the intersections of the plate with the portions of the body located between the channels and the inner walls. When the plate is coupled with the body, for example via bonding, brazing, etc., the plate may warp. Because the coupling may be performed only around the outer edge, no additional bonding may exist at other interfaces of the plate and body. Even slight warping of the plate may produce an uneven surface at the interfaces between the upper plate and annular body, and interface locations where warping has occurred may not properly couple with the annular body. As such, in operation, fluid may leak between the first and second fluid channels, as well as between the first fluid channel and a central region. Such leakage can affect fluid delivery into the processing region, which can impact deposition or etching. Aspects of the present technology, however, overcome many if not all of these issues by providing components that are less likely to warp, and/or designs that are less impacted by warping.

FIG. 1shows a top plan view of one embodiment of a processing tool100of deposition, etching, baking, and/or curing chambers according to disclosed embodiments. In the figure, a pair of FOUPs (front opening unified pods)102supply substrates (e.g., various specified diameter semiconductor wafers) that may be received by robotic arms104and placed into a low-pressure holding area106before being placed into one of the substrate processing sections108a-fof the tandem process chambers109a-c. A second robotic arm110may be used to transport the substrates from the holding area106to the processing chambers108a-fand back.

The substrate processing sections108a-fof the tandem process chambers109a-cmay include one or more system components for depositing, annealing, curing and/or etching substrates or films thereon. Exemplary films may be flowable dielectrics, but many types of films may be formed or processed with the processing tool. In one configuration, two pairs of the tandem processing sections of the processing chamber (e.g.,108c-dand108e-f) may be used to deposit the dielectric material on the substrate, and the third pair of tandem processing sections (e.g.,108a-b) may be used to anneal the deposited dielectric. In another configuration, the two pairs of the tandem processing sections of processing chambers (e.g.,108c-dand108e-f) may be configured to both deposit and anneal a dielectric film on the substrate, while the third pair of tandem processing sections (e.g.,108a-b) may be used for UV or E-beam curing of the deposited film. In still another configuration, all three pairs of tandem processing sections (e.g.,108a-f) may be configured to deposit and cure a dielectric film on the substrate or etch features into a deposited film.

In yet another configuration, two pairs of tandem processing sections (e.g.,108c-dand108e-f) may be used for both deposition and UV or E-beam curing of the dielectric, while a third pair of tandem processing sections (e.g.108a-b) may be used for annealing the dielectric film. In addition, one or more of the tandem processing sections108a-fmay be configured as a treatment chamber, and may be a wet or dry treatment chamber. These process chambers may include heating the dielectric film in an atmosphere that includes moisture. Thus, embodiments of system100may include wet treatment tandem processing sections108a-band anneal tandem processing sections108c-dto perform both wet and dry anneals on the deposited dielectric film. It will be appreciated that additional configurations of deposition, annealing, and curing chambers for dielectric films are contemplated by system100.

FIG. 2Ais a cross-sectional view of an exemplary process chamber section200with partitioned plasma generation regions within the processing chambers. During film deposition (e.g., silicon oxide, silicon nitride, silicon oxynitride, or silicon oxycarbide), a process gas may be flowed into the first plasma region215through a gas inlet assembly205. A remote plasma system (RPS)201may process a gas which then travels through gas inlet assembly205. Two distinct gas supply channels are visible within the gas inlet assembly205. A first channel206carries a gas that passes through the remote plasma system (RPS)201, while a second channel207bypasses the RPS201. The first channel206may be used for the process gas and the second channel207may be used for a treatment gas in disclosed embodiments. The process gas may be excited prior to entering the first plasma region215within a remote plasma system (RPS)201. A lid212, a showerhead225, and a substrate support265, having a substrate255disposed thereon, are shown according to disclosed embodiments. The lid212may be pyramidal, conical, or of another similar structure with a narrow top portion expanding to a wide bottom portion. Additional geometries of the lid212may also be used. The lid (or conductive top portion)212and showerhead225are shown with an insulating ring220in between, which allows an AC potential to be applied to the lid212relative to showerhead225. The insulating ring220may be positioned between the lid212and the showerhead225enabling a capacitively coupled plasma (CCP) to be formed in the first plasma region. A baffle (not shown) may additionally be located in the first plasma region215to affect the flow of fluid into the region through gas inlet assembly205.

A fluid, such as a precursor, for example a silicon-containing precursor, may be flowed into the processing region233by embodiments of the showerhead described herein. Excited species derived from the process gas in the plasma region215may travel through apertures in the showerhead225and react with the precursor flowing into the processing region233from the showerhead. Little or no plasma may be present in the processing region233. Excited derivatives of the process gas and the precursor may combine in the region above the substrate and, on occasion, on the substrate to form a film on the substrate that may be flowable in disclosed applications. For flowable films, as the film grows, more recently added material may possess a higher mobility than underlying material. Mobility may decrease as organic content is reduced by evaporation. Gaps may be filled by the flowable film using this technique without leaving traditional densities of organic content within the film after deposition is completed. A curing step may still be used to further reduce or remove the organic content from a deposited film.

Exciting the process gas in the first plasma region215directly, exciting the process gas in the RPS, or both, may provide several benefits. The concentration of the excited species derived from the process gas may be increased within the processing region233due to the plasma in the first plasma region215. This increase may result from the location of the plasma in the first plasma region215. The processing region233may be located closer to the first plasma region215than the remote plasma system (RPS)201, leaving less time for the excited species to leave excited states through collisions with other gas molecules, walls of the chamber, and surfaces of the showerhead.

The uniformity of the concentration of the excited species derived from the process gas may also be increased within the processing region233. This may result from the shape of the first plasma region215, which may be more similar to the shape of the processing region233. Excited species created in the remote plasma system (RPS)201may travel greater distances in order to pass through apertures near the edges of the showerhead225relative to species that pass through apertures near the center of the showerhead225. The greater distance may result in a reduced excitation of the excited species and, for example, may result in a slower growth rate near the edge of a substrate. Exciting the process gas in the first plasma region215may mitigate this variation.

The processing gas may be excited in the RPS201and may be passed through the showerhead225to the processing region233in the excited state. Alternatively, power may be applied to the first processing region to either excite a plasma gas or enhance an already exited process gas from the RPS. While a plasma may be generated in the processing region233, a plasma may alternatively not be generated in the processing region. In one example, the only excitation of the processing gas or precursors may be from exciting the processing gas in the RPS201to react with the precursors in the processing region233.

The processing chamber and this discussed tool are more fully described in patent application Ser. No. 12/210,940 filed on Sep. 15, 2008, and patent application Ser. No. 12/210,982 filed on Sep. 15, 2008, which are incorporated herein by reference to the extent not inconsistent with the claimed aspects and description herein.

FIGS. 2B-2Care side schematic views of one embodiment of the precursor flow processes in the processing chambers and the gas distribution assemblies described herein. The gas distribution assemblies for use in the processing chamber section200may be referred to as dual channel showerheads (DCSH) or triple channel showerheads (TCSH) and are detailed in the embodiments described inFIGS. 3A-3G,4A-4B, and5A-5C herein. The dual or triple channel showerhead may allow for flowable deposition of a dielectric material, and separation of precursor and processing fluids during operation. The showerhead may alternatively be utilized for etching processes that allow for separation of etchants outside of the reaction zone to provide limited interaction with chamber components.

Precursors may be introduced into the distribution zone by first being introduced into an internal showerhead volume294defined in the showerhead225by a first manifold226, or upper plate, and second manifold227, or lower plate. The manifolds may be perforated plates that define a plurality of apertures. The precursors in the internal showerhead volume294may flow295into the processing region233via apertures296formed in the lower plate. This flow path may be isolated from the rest of the process gases in the chamber, and may provide for the precursors to be in an unreacted or substantially unreacted state until entry into the processing region233defined between the substrate217and a bottom of the lower plate227. Once in the processing region233, the precursor may react with a processing gas. The precursor may be introduced into the internal showerhead volume294defined in the showerhead225through a side channel formed in the showerhead, such as channels322,422as shown in the showerhead embodiments herein. The process gas may be in a plasma state including radicals from the RPS unit or from a plasma generated in the first plasma region. Additionally, a plasma may be generated in the processing region.

Processing gases may be provided into the first plasma region215, or upper volume, defined by the faceplate217and the top of the showerhead225. The processing gas may be plasma excited in the first plasma region215to produce process gas plasma and radicals. Alternatively, the processing gas may already be in a plasma state after passing through a remote plasma system prior to introduction to the first plasma processing region215defined by the faceplate217and the top of the showerhead225.

The processing gas including plasma and radicals may then be delivered to the processing region233for reaction with the precursors though channels, such as channels290, formed through the apertures in the showerhead plates or manifolds. The processing gasses passing though the channels may be fluidly isolated from the internal showerhead volume294and may not react with the precursors passing through the internal showerhead volume294as both the processing gas and the precursors pass through the showerhead225. Once in the processing volume, the processing gas and precursors may mix and react.

In addition to the process gas and a dielectric material precursor, there may be other gases introduced at varied times for varied purposes. A treatment gas may be introduced to remove unwanted species from the chamber walls, the substrate, the deposited film and/or the film during deposition. A treatment gas may be excited in a plasma and then used to reduce or remove residual content inside the chamber. In other disclosed embodiments the treatment gas may be used without a plasma. When the treatment gas includes water vapor, the delivery may be achieved using a mass flow meter (MFM), an injection valve, or by commercially available water vapor generators. The treatment gas may be introduced from the first processing region, either through the RPS unit or bypassing the RPS unit, and may further be excited in the first plasma region.

The axis292of the opening of apertures291and the axis297of the opening of apertures296may be parallel or substantially parallel to one another. Alternatively, the axis292and axis297may be angled from each other, such as from about 1° to about 80°, for example, from about 1° to about 30°. Alternatively, each of the respective axes292may be angled from each other, such as from about 1° to about 80°, for example, from about 1° to about 30°, and each of the respective axis297may be angled from each other, such as from about 1° to about 80°, for example, from about 1° to about 30°.

The respective openings may be angled, such as shown for aperture291inFIG. 2B, with the opening having an angle from about 1° to about 80°, such as from about 1° to about 30°. The axis292of the opening of apertures291and the axis297of the opening of apertures296may be perpendicular or substantially perpendicular to the surface of the substrate217. Alternatively, the axis292and axis297may be angled from the substrate surface, such as less than about 5°.

FIG. 2Cillustrates a partial schematic view of the processing chamber200and showerhead225illustrating the precursor flow295from the internal volume294through apertures296into the processing region233. The figure also illustrates an alternative embodiment showing axis297and297′ of two apertures296being angled from one another.

FIG. 2Dshows a simplified cross-sectional view of another exemplary processing system200according to embodiments of the present technology that may include an alternative fluid delivery system. Distribution of the processing gas may be achieved by use of a faceplate217as shown. Processing gases may be delivered through a fluid supply system210, and the chamber may or may not include components as previously described including RPS201, first plasma region215, insulating ring220, showerhead225, processing region233, pedestal265, and substrate255. The system may also include cooling plate203in the modified distribution system.

Plasma generating gases and/or plasma excited species, depending on use of the RPS201, may pass through a plurality of holes, shown inFIG. 2E, in faceplate217for a more uniform delivery into the first plasma region215. Exemplary configurations include having the gas inlet assembly205open into a gas supply region258partitioned from the first plasma region215by faceplate217so that the gases/species flow through the holes in the faceplate217into the first plasma region215. Structural and operational features may be selected to prevent significant backflow of plasma from the first plasma region215back into the supply region258, gas inlet assembly205, and fluid supply system210. The structural features may include the selection of dimensions and cross-sectional geometry of the apertures in faceplate217that deactivates back-streaming plasma. The operational features may include maintaining a pressure difference between the gas supply region258and first plasma region215that maintains a unidirectional flow of plasma through the showerhead225.

The processing system may further include a power supply240electrically coupled with the processing chamber to provide electric power to the faceplate217and/or showerhead225to generate a plasma in the first plasma region215or processing region233. The power supply may be configured to deliver an adjustable amount of power to the chamber depending on the process performed.

FIG. 2Eshows a detailed view of the features affecting the processing gas distribution through faceplate217. As shown inFIGS. 2D and 2E, faceplate217, cooling plate203, and gas inlet assembly205intersect to define a gas supply region258into which process gases may be delivered from gas inlet205. The gases may fill the gas supply region258and flow to first plasma region215through apertures259in faceplate217. The apertures259may be configured to direct flow in a substantially unidirectional manner such that process gases may flow into processing region233, but may be partially or fully prevented from backflow into the gas supply region258after traversing the faceplate217.

An additional dual-channel showerhead, as well as this processing system and chamber, are more fully described in patent application Ser. No. 13/251,714 filed on Oct. 3, 2011, which is hereby incorporated by reference for all purposes to the extent not inconsistent with the claimed features and description herein.

FIG. 3Aillustrates an upper perspective view of a gas distribution assembly300. In usage, the gas distribution system300may have a substantially horizontal orientation such that an axis of the gas apertures formed therethrough may be perpendicular or substantially perpendicular to the plane of the substrate support (see substrate support265inFIG. 2A).FIG. 3Billustrates a bottom perspective view of the gas distribution assembly300.FIG. 3Cis a bottom plan view of the gas distribution assembly300.FIGS. 3D and 3Eare cross sectional views of disclosed embodiments of gas distribution assembly300taken along line A-A ofFIG. 3C.

Referring toFIGS. 3A-3E, the gas distribution assembly300generally includes the annular body340, the upper plate320, and the lower plate325. The annular body340may be a ring which has an inner annular wall301located at an inner diameter, an outer annular wall305located at an outer diameter, an upper surface315, and a lower surface310. The upper surface315and lower surface310define the thickness of the annular body340. A conduit350or annular temperature channel may be defined within the annular body and may be configured to receive a cooling fluid or a heating element that may be used to maintain or regulate the temperature of the annular body. As shown inFIG. 3A, the cooling channel350may include an inlet and outlet on the outer diameter305of the annular body. This may provide access from the side of the processing chamber from which a cooling fluid may be flowed. An additional embodiment is shown inFIG. 3B, in which conduit355may be formed in the bottom surface310and a heating element may be disposed therein. A heater recess342may be formed in the bottom surface310and be adapted to hold the heating element, and which provides access for disposing the heating element within the annular temperature channel or conduit355.

One or more recesses and/or channels may be formed in or defined by the annular body as shown in disclosed embodiments including that illustrated inFIG. 3D. The annular body may include an upper recess303formed in the upper surface, and a first lower recess302formed in the lower surface at the inner annular wall301. The upper recess303may be a first upper recess formed in the annular body340. The annular body may also include a second lower recess304formed in the lower surface310below and radially outward from the first lower recess302. As shown inFIG. 3D, a first fluid channel306may be defined in the upper surface315, and may be located in the annular body radially inward of the upper recess303. The first fluid channel306may be annular in shape and be formed the entire distance around the annular body340. In disclosed embodiments, a bottom portion of the upper recess303intersects an outer wall of the first fluid channel306. The first fluid channel may also be at least partially radially outward of the second lower recess304. A plurality of ports312may be defined in an inner wall of the first fluid channel, also the inner annular wall301of the annular body340. The ports312may provide access between the first fluid channel and the internal volume defined between the upper plate320and lower plate325. The ports may be defined around the circumference of the channel at specific intervals, and may facilitate distribution across the entire region of the volume defined between the upper and lower plates. The intervals of spacing between the ports312may be constant, or may be varied in different locations to affect the flow of fluid into the volume. The inner and outer walls, radially, of the first fluid channel306may be of similar or dissimilar height. For example, the inner wall may be formed higher than the outer wall to affect the distribution of fluids in the first fluid channel to avoid or substantially avoid the flow of fluid over the inner wall of the first fluid channel.

Again referring toFIG. 3D, a second fluid channel308amay be defined in the upper surface315that is located in the annular body radially outward of the first fluid channel306. Second fluid channel308amay be an annular shape and be located radially outward from and concentric with first fluid channel306. The second fluid channel308amay also be located radially outward of the first upper recess303such that the second fluid channel308ais not covered by the upper plate320as discussed below. A second plurality of ports314may be defined in the portion of the annular body340defining the outer wall of the first fluid channel306and the inner wall of the second fluid channel308a. The second plurality of ports314may be located at intervals of a pre-defined distance around the channel to provide fluid access to the first fluid channel306at several locations about the second fluid channel308a. A second upper recess309may be formed in a top portion of the second fluid channel308ain both the inner wall and outer wall of the second fluid channel. The second upper recess may be configured to receive an annular member316that may be positioned to cover the second fluid channel by extending radially inward and outward into the annular body past the inner and outer walls of the channel into the recess spaces309. The annular member316may be braised or bonded with the annular body340to fluidly isolate the second fluid channel308afrom above. In operation, a precursor may be flowed from outside the process chamber to a delivery channel322located in the side of the annular body340. The fluid may flow into the second fluid channel308a, through the second plurality of ports314into the first fluid channel306, through the first plurality of ports312into the internal volume defined between the upper and lower plates, and through the third apertures375located in the bottom plate. As such, a fluid provided in such a fashion can be isolated or substantially isolated from any fluid delivered into the first plasma region through apertures360until the fluids separately exit the lower plate325.

By providing annular member316to cover the second fluid channel308a, leakage between the first and second fluid channels may be substantially eliminated, and in disclosed embodiments may be completely eliminated. Annular member316may be coupled with the annular body340, such as by bonding for example, on both sides of the channel in both recesses309. Because the annular member316does not extend radially beyond the width of the second fluid channel308aand recesses309, annular member316is less prone to radial warping. As such, an improved covering profile may be produced, and leakage from the second fluid channel may be substantially or completely prevented.

The upper plate320may be a disk-shaped body, and may be coupled with the annular body340at the first upper recess303. The upper plate320may thus cover the first fluid channel306to prevent or substantially prevent fluid flow from the top of the first fluid channel306. The upper plate may have a diameter selected to mate with the diameter of the upper recess303, and the upper plate may comprise a plurality of first apertures360formed therethrough. The first apertures360may extend beyond a bottom surface of the upper plate320thereby forming a number of raised cylindrical bodies. In between each raised cylindrical body may be a gap. As seen inFIG. 3A, the first apertures360may be arranged in a polygonal pattern on the upper plate320, such that an imaginary line drawn through the centers of the outermost first apertures360define or substantially define a polygonal figure, which may be for example, a six-sided polygon.

The pattern may also feature an array of staggered rows from about 5 to about 60 rows, such as from about 15 to about 25 rows of first apertures360. Each row may have, along the y-axis, from about 5 to about 20 first apertures360, with each row being spaced between about 0.4 and about 0.7 inches apart. Each first aperture360in a row may be displaced along the x-axis from a prior aperture between about 0.4 and about 0.8 inches from each respective diameter. The first apertures360may be staggered along the x-axis from an aperture in another row by between about 0.2 and about 0.4 inches from each respective diameter. The first apertures360may be equally spaced from one another in each row. Referring toFIG. 3D, an edge portion of the upper plate320may comprise a second thickness greater than a first thickness located more towards the central portion of the plate, and the second thickness may be equivalent or substantially equivalent to the height of the outer wall of first upper recess303. The edge portion may extend radially inward from an outer edge a distance equivalent or substantially equivalent to a bottom portion of the upper recess. Accordingly, the edge portion may not extend radially inward past the inward most portion of first upper recess303in disclosed embodiments.

The lower plate325may have a disk-shaped body having a number of second apertures365and third apertures375formed therethrough, as especially seen inFIG. 3C. The lower plate325may have multiple thicknesses, with the thickness of defined portions greater than the central thickness of the upper plate320, and in disclosed embodiments at least about twice the thickness of the upper plate320. The lower plate325may also have a diameter that mates with the diameter of the inner annular wall301of the annular body340at the first lower recess302. As mentioned, the lower plate325may comprise multiple thicknesses, and for example, a first thickness of the plate may be the thickness through which the third apertures375extend. A second thickness greater than the first may be the thickness of an edge region of the plate that intersects the first lower recess302of the annular body340. The second thickness with respect to the first lower recess may be dimensioned similar to the edge portion of the upper plate with respect to the first upper recess. In disclosed embodiments, the first and second thicknesses are substantially similar. A third thickness greater than the second may be a thickness of the plate around the second apertures365. For example, the second apertures365may be defined by the lower plate325as cylindrical bodies extending up to the upper plate320. In this way, channels may be formed between the first and second apertures that are fluidly isolated from one another. Additionally, the volume formed between the upper and lower plates may be fluidly isolated from the channels formed between the first and second apertures. As such, a fluid flowing through the first apertures360will flow through the second apertures365and a fluid within the internal volume between the plates will flow through the third apertures375, and the fluids will be fluidly isolated from one another until they exit the lower plate325through either the second or third apertures. This separation may provide numerous benefits including preventing a radical precursor from contacting a second precursor prior to reaching a reaction zone. By preventing the interaction of the gases, deposition within the chamber may be minimized prior to the processing region in which deposition is desired.

The second apertures365may be arranged in a pattern that aligns with the pattern of the first apertures360as described above. In one embodiment, when the upper plate320and bottom plate325are positioned one on top of the other, the axes of the first apertures360and second apertures365align. In disclosed embodiments, the upper and lower plates may be coupled with one another or directly bonded together. Under either scenario, the coupling of the plates may occur such that the first and second apertures are aligned to form a channel through the upper and lower plates. The plurality of first apertures360and the plurality of second apertures365may have their respective axes parallel or substantially parallel to each other, for example, the apertures360,365may be concentric. Alternatively, the plurality of first apertures360and the plurality of second apertures365may have the respective axis disposed at an angle from about 1° to about 30° from one another. At the center of the bottom plate325there may be no second aperture365.

As stated previously, the gas distribution assembly300generally consists of the annular body340, the upper plate320, and the lower plate325. The lower plate325may be positioned within the first lower recess303with the raised cylindrical bodies facing toward the bottom surface of the upper plate320, as shown inFIG. 3D. The bottom plate325may then be positioned in the first lower recess304and rotatably oriented so that the axes of the first and second apertures360,365may be aligned. The upper plate320may be sealingly coupled with the bottom plate325to fluidly isolate the first and second apertures360,365from the third apertures375. For example, the upper plate320may be brazed to the bottom plate325such that a seal is created between a surface of the raised cylindrical bodies on the lower plate325, and a surface of the bottom of the upper plate320. The upper plate320and bottom plate325may then be E-beam welded or otherwise bonded to the annular body340. The upper plate320may be E-beam welded such that a seal is created between an outer edge of the circular body and an inner edge of the upper recess303. The bottom plate325may be E-beam welded such that a seal is created between an outer edge of the circular body and the inner annular wall301. In disclosed embodiments, the surfaces of the gas distribution assembly300may be electro-polished, plated with metal, or coated with various metal-based substances or oxides.

The plurality of second apertures365and the plurality of third apertures375may form alternating staggered rows. The third apertures375may be arranged in between at least two of the second apertures365of the bottom plate325. Between each second aperture365there may be a third aperture375, which is evenly spaced between the two second apertures365. There may also be a number of third apertures375positioned around the center of the bottom plate325in a hexagonal pattern, such as for example six third apertures, or a number of third apertures375forming another geometric shape. There may be no third aperture375formed in the center of the bottom plate325. There may also be no third apertures375positioned between the perimeter second apertures365which form the vertices of the polygonal pattern of second apertures. Alternatively there may be third apertures375located between the perimeter second apertures365, and there may also be additional third apertures375located outwardly from the perimeter second apertures365forming the outermost ring of apertures as shown, for example, inFIG. 3C.

Alternatively, the arrangement of the first and second apertures may make any other geometrical pattern, and may be distributed as rings of apertures located concentrically outward from each other and based on a centrally located position on the plate. As one example, and without limiting the scope of the technology,FIG. 3Ashows a pattern formed by the apertures that includes concentric hexagonal rings extending outwardly from the center. Each outwardly located ring may have the same number, more, or less apertures than the preceding ring located inwardly. In one example, each concentric ring may have an additional number of apertures based on the geometric shape of each ring. In the example of a six-sided polygon, each ring moving outwardly may have six apertures more than the ring located directly inward, with the first internal ring having six apertures. With a first ring of apertures located nearest to the center of the upper and bottom plates, the upper and bottom plates may have more than two rings, and depending on the geometric pattern of apertures used, may have between about one and about fifty rings of apertures. Alternatively, the plates may have between about two and about forty rings, or up to about thirty rings, about twenty rings, about fifteen rings, about twelve rings, about ten rings, about nine rings, about eight rings, about seven rings, about six rings, etc. or less. In one example, as shown inFIG. 3A, there may be nine hexagonal rings on the exemplary upper plate.

The concentric rings of apertures may also not have one of the concentric rings of apertures, or may have one of the rings of apertures extending outward removed from between other rings. For example with reference toFIG. 3A, where an exemplary nine hexagonal rings are on the plate, the plate may instead have eight rings, but it may be ring four that is removed. In such an example, channels may not be formed where the fourth ring would otherwise be located which may redistribute the gas flow of a fluid being passed through the apertures. The rings may still also have certain apertures removed from the geometric pattern. For example again with reference toFIG. 3A, a tenth hexagonal ring of apertures may be formed on the plate shown as the outermost ring. However, the ring may not include apertures that would form the vertices of the hexagonal pattern, or other apertures within the ring.

The first, second, and third apertures360,365,375may all be adapted to allow the passage of fluid therethrough. The first and second apertures360,365may have cylindrical shape and may, alternatively, have a varied cross-sectional shape including conical, cylindrical, or a combination of multiple shapes. In one example, as shown inFIG. 3D, the first and second apertures may have a substantially cylindrical shape, and the third apertures may be formed by a series of cylinders of different diameters. For example, the third apertures may comprise three cylinders where the second cylinder is of a diameter smaller than the diameters of the other cylinders. These and numerous other variations can be used to modulate the flow of fluid through the apertures.

When all first and second apertures are of the same diameter, the flow of gas through the channels may not be uniform. As process gases flow into the processing chamber, the flow of gas may be such as to preferentially flow a greater volume of gas through certain channels. As such, certain of the apertures may be reduced in diameter from certain other apertures in order to redistribute the precursor flow as it is delivered into a first plasma region. The apertures may be selectively reduced in diameter due to their relative position, such as near a baffle, and as such, apertures located near the baffle may be reduced in diameter to reduce the flow of process gas through those apertures. In one example, as shown inFIG. 3A, where nine hexagonal rings of first apertures are located concentrically on the plates, certain rings of apertures may have some or all of the apertures reduced in diameter. For example, ring four may include a subset of first apertures that have a smaller diameter than the first apertures in the other rings. Alternatively, rings two through eight, two through seven, two through six, two through five, two through four, three through seven, three through six, three through five, four through seven, four through six, two and three, three and four, four and five, five and six, etc., or some other combination of rings may have reduced aperture diameters for some or all of the apertures located in those rings.

Referring again toFIG. 3D, a pair of isolation channels,318may be formed in the annular body340. One of the pair of isolation channels318may be defined in the upper surface315of the annular body340, and the other of the pair of isolation channels318may be defined in the lower surface310of the annular body340. The pair of isolation channels may be vertically aligned with one another, and in disclosed embodiments may be in direct vertical alignment. Alternatively, the pair of isolation channels may be offset from vertical alignment in either direction. The channels may provide locations for isolation barriers such as o-rings in disclosed embodiments.

Turning toFIG. 3E, additional features of gas distribution assemblies are shown according to disclosed embodiments, and may include many of the features described above with respect toFIG. 3D. The assembly300includes annular body340having inner annular wall301, outer annular wall305, upper surface315, and lower surface310. The annular body340may additionally include an upper recess303, a first lower recess302, and a second lower recess304. The annular body may also have a first fluid channel306formed in the upper surface315with a plurality of ports312defined in the inner channel wall that provide fluid access to a volume formed between upper plate320and lower plate325. Lower plate325may be coupled with annular body340at first lower recess302. Lower plate325may additionally define first and second apertures as discussed above with regard toFIG. 3D.

Upper plate320may be coupled with annular body340at upper recess303. First fluid channel306may be defined similar to first fluid channel306ofFIG. 3D. Alternatively, the inner and outer walls of the first fluid channel306may be of substantially similar height, and in disclosed embodiments may be of identical height. Upper plate320may cover first fluid channel306in order to prevent a flow path from the top of the first fluid channel306. The first plurality of ports312may be defined in the annular body similar to that ofFIG. 3D. Alternatively, the first plurality of ports312may be partially formed in the upper surface315at the inner annular wall301. When upper plate320is coupled with the annular body340, the upper plate may further define the top of the plurality of ports312.

A second fluid channel308bmay be formed in the upper surface315of annular body340, and may be configured to receive a fluid delivered through fluid delivery channel322as previously described. Second fluid channel308b, however, may be located radially inward of the first upper recess303such that the second fluid channel308bis covered by the upper plate320. An outer wall of second fluid channel308bmay intersect a bottom portion of upper recess303. A second plurality of ports314may be defined by a portion of the annular body forming an inner wall of the second fluid channel308band the outer wall of first fluid channel306. The ports may provide fluid communication between the first and second fluid channels, and may be located similarly as described above. Upper plate320may be configured to limit warping at each interface of contact with the annular body340. For example, upper plate320may have a first thickness in the central portion of the upper plate320where the apertures are located, and may be a second thickness greater than the first thickness at the edge portions of the plate. These edge portions may extend from the upper recess303over the second fluid channel308b, the first fluid channel306, and the inner annular wall301. The increased thickness of the upper plate320at the edge regions may better absorb the stress produced during the coupling of the upper plate to the annular body, and thereby reduce warping.

A portion of upper plate320may extend a distance into the second fluid channel308b. The portion of the upper plate may extend into the second channel below a level of the bottom of the upper recess303. In disclosed embodiments, second fluid channel308bis formed to a greater depth in the upper surface315than the first fluid channel306. The portion of upper plate320extending into the second fluid channel308bmay extend to a depth equivalent to the depth of the first fluid channel306within the annular body340. By having a portion of the upper plate extend into the second fluid channel308b, warping that may occur in the upper plate when it is coupled with the annular body340may not produce any leak paths between the first and second fluid channels as the extent of warping may be overcome by the amount of the upper plate320that extends into the second fluid channel308b. The second plurality of ports314may be defined similar to those ofFIG. 3D, or alternatively may be partially formed in the upper surface similar to the first plurality of ports312. The top of the plurality of ports314may be defined by the bottom surface of the upper plate320. The second plurality of ports314may be formed at an angle increasing vertically between the second fluid channel308band the first fluid channel306. By forming the ports at an angle, the ports may not be blocked by the portion of the upper plate extending into the second fluid channel308b. In disclosed embodiments the second plurality of ports314may be slots of various shapes or dimensions formed in the annular body. The slots may be formed at an angle increasing or upward from the second fluid channel308bto the first fluid channel306such that the ports are fluidly accessible below the portion of the upper plate320extending into the second fluid channel308b.

A pair of isolation channels324may be formed in the gas distribution assembly in disclosed embodiments where at least a portion of the isolation channels are vertically aligned with the portion of the annular body forming the inner wall of the second fluid channel308band the inner wall of the first fluid channel306. To produce this configuration, one of the pair of isolation channels may be defined in the upper plate at a location radially inward from the first upper recess. The other of the pair of isolation channels may be defined in the lower surface310of the annular body, and the pair of isolation channels may be vertically aligned with one another. In disclosed embodiments the pair of isolation channels may be in direct vertical alignment. In operation, the isolation channels may receive o-rings, for example, or other isolation devices. By providing the isolation channels at a location that is at least partially aligned with the shared wall of the first and second fluid channels, the compression produced at the isolation channels may be used to offset, reduce, or remove warping that may have occurred at the interface of the upper plate320and the annular body.

Referring toFIGS. 4A-4B, gas distribution assembly400, or showerhead, is provided including a first or upper plate420and a second or lower plate425, and the top of the lower plate425may be configured to be coupled with the bottom of the upper plate420. The upper and lower plates may be perforated plates with a plurality of apertures defined in each plate. In usage, the orientation of the showerhead400to the substrate may be done in such a way that the axis of any apertures formed in the showerhead may be perpendicular or substantially perpendicular to the substrate plane.

Referring toFIG. 4B, annular body440may include an upper recess403in upper surface415, and a lower recess402in lower surface410. A first fluid channel406may be defined in the lower surface410and may be located in the annular body radially inward of the lower recess402. The first fluid channel may be annular in shape, and the channel may be covered by lower plate425. A plurality of ports412may be at least partially defined in the annular body at the inner annular wall401, and may be located along the entire channel at defined intervals that may be equal or modified across the plurality of ports. In disclosed embodiments, lower plate425may define a top portion of the plurality of ports412. Upper plate420may be coupled with the annular body440at upper recess403, and the upper plate420may define a plurality of first apertures460. Lower plate425may be coupled with the annular body440at the lower recess402, and may cover first fluid channel406. Lower plate425may define a plurality of second apertures465that may align with the first apertures460defined in the upper plate420in order to form a first set of channels through the assembly400. The lower plate425may also define a plurality of third apertures475that are located between and around the second apertures465. The lower plate425may include raised portions around second apertures465that extend up to the upper plate420to produce fluidly isolated channels through the assembly.

The upper and lower plates may be sealingly coupled with one another such that the first and second apertures are aligned to form a channel through the upper and lower plates with the raised portions of the lower plate such that an internal volume is defined between the upper and lower plate. The volume may be fluidly accessed through the plurality of ports412. The assembly may be configured such that a first fluid may flow through the first apertures and extend through the assembly400through the isolated channels formed between the first and second apertures. Additionally, a second fluid may be flowed through the assembly via the first fluid channel406and delivered into the volume defined between the upper and lower plates. The fluid flowing through the volume may flow through the third apertures and around the raised portions of the lower plate such that the first and second fluid may be fluidly isolated through the showerhead, and remain separated until they exit the lower plate through the second and third apertures respectively.

The first apertures460may be shaped to suppress the migration of ionically-charged species out of the first plasma region215described previously, while allowing uncharged neutral or radical species to pass through the showerhead225, or gas distribution assembly400. These uncharged species may include highly reactive species that are transported with less reactive carrier gas through the holes. As noted above, the migration of ionic species through the holes may be reduced, and in some instances completely suppressed. Controlling the amount of ionic species passing through the gas distribution assembly400may provide increased control over the gas mixture brought into contact with the underlying wafer substrate, which in turn increases control of the deposition and/or etch characteristics of the gas mixture. Accordingly, in disclosed embodiments, the first apertures may include a conical shape extending through the upper plate with decreasing diameter in order to control fluid characteristics. This upper plate may specifically act as an ion-suppression plate or ion blocker such that a configuration effectively combines ion-suppression directly into the showerhead design, and an additional suppression element may not be additionally required.

Each first aperture460may have a conical inlet portion tapering to a first cylindrical portion that intersects second apertures465. The second apertures may include multiple sections of various shapes to further affect fluid flow through the channels formed between the first and second apertures. In an exemplary design, the second apertures465may include multiple cylindrical sections of increasing diameter leading to a conical section extending with increasing diameter to the bottom of the lower plate425. Third apertures475may similarly include multiple sections of various shapes, and in an exemplary configuration the third apertures475may include multiple cylindrical sections of decreasing diameter leading to a conical section extending with increasing diameter to the bottom of the lower plate425. In disclosed embodiments, the second and third apertures include at least three sections of different shape or diameter.

For ion-suppression assemblies such as exemplary configuration assembly400, the number of apertures may be greater than the number of apertures in configurations such as exemplary assemblies ofFIGS. 3D and 3E. Providing a greater number of apertures may increase the density of species delivered to the processing region of the chamber.FIG. 4Ashows a bottom view of gas distribution assembly400including lower plate425with second apertures465and third apertures475. Although only one quadrant of apertures is shown, it will be readily understood that the apertures are defined similarly in all four quadrants of the assembly. WhileFIG. 3Ashows an exemplary nine hexagonal rings of apertures, a similarly sized gas distribution assembly such as shown inFIG. 4Amay include between about eighteen and twenty-five rings of apertures. The total number of apertures in the high-density design illustrated inFIGS. 4A-4Bmay include between 2-10 times as many total second and third apertures. The high-density configuration as shown inFIG. 3Emay include an additional second aperture365directly in the center of the plate.

Referring back toFIG. 4B, the gas distribution assembly may additionally include a second fluid channel408defined in the lower surface410that is located in the annular body440radially outward of the first fluid channel406. The second fluid channel408may be formed around the entire annular body360, and may also be concentric with the first fluid channel406. A second plurality of ports414may be defined in at least a portion of the annular body defining an outer wall of the first fluid channel406and an inner wall of the second fluid channel408. The second fluid channel408may also be located radially inward of the lower recess such that the second fluid channel is covered by the lower plate425. Similar to the design described inFIG. 4E, a portion of the lower plate may extend up into the second fluid channel408.

The portion of the lower plate425may extend into the second channel above a level of the top of the lower recess402. In disclosed embodiments, second fluid channel408is formed to a greater height in the lower surface410than the first fluid channel406. The portion of lower plate425extending into the second fluid channel408may extend to a height equivalent to the height of the first fluid channel406or less within the annular body440, or to a height equivalent to about half of the height of first fluid channel406. As explained above, a portion of the lower plate extending into the second fluid channel408may limit the effects of warping that may occur in the lower plate when it is coupled with the annular body440. The second plurality of ports414may be defined similar to those ofFIG. 3Dor3E but in the lower surface410. The bottom of the plurality of ports414may be defined by the top surface of the lower plate425.

The second plurality of ports414may be formed at an angle decreasing vertically between the second fluid channel408and the first fluid channel406. By forming the ports at an angle, the ports may not be blocked by the portion of the lower plate extending into the second fluid channel408. In disclosed embodiments the second plurality of ports414may be slots of various shapes or dimensions formed in the annular body, and may be angled downward from the second fluid channel408to the first fluid channel406such that the ports are fluidly accessible above the portion of the lower plate extending into the second fluid channel408. In operation, a fluid may be delivered through the gas distribution assembly400through a side port in the chamber, for example, fluid delivery channel422. The fluid may flow into second fluid channel408and then through the second plurality of ports414that may fluidly couple the second fluid channel408with the first fluid channel406. The fluid may then flow through the first plurality of ports412that may fluidly couple the first fluid channel406with the volume defined between the upper plate420and lower plate425. The fluid may continue to flow through third apertures475into the processing region. In this configuration, such a fluid may be fluidly isolated from the first and second apertures that form channels through the gas distribution assembly. In this way, the distribution assembly may prevent the flow of this fluid from accessing the first apertures, and may prevent the fluid from flowing through the top of the gas distribution assembly without a pressure differential or forced flow.

FIG. 5Ashows an exemplary gas distribution assembly500configured to provide three isolated fluid paths to a processing region. The assembly500may include similar components as previously described including an annular body540having an inner annular wall501located at an inner diameter, an outer annular wall505located at an outer diameter, an upper surface515, and a lower surface510. Gas distribution assembly500may include an upper plate520coupled with the annular body540that defines a first set of apertures. Intermediate plate530may be coupled with the upper plate520and may comprise a plurality of second apertures and a plurality of third apertures. The intermediate plate530may be coupled such that the second apertures align with the first apertures of the upper plate. The assembly may additionally include a lower plate525coupled with the annular body540and the intermediate plate530. The lower plate525may define a plurality of fourth apertures that align with the first apertures of the upper plate and the second apertures of the intermediate plate to form a first plurality of fluid channels561through the plates. The lower plate may also define a fifth set of apertures that align with the third apertures of the intermediate plate to form a second plurality of fluid channels566through the intermediate and lower plates. The second plurality of fluid channels566may be fluidly isolated from the first plurality of fluid channels561. The lower plate may also define a sixth set of apertures that form a third plurality of fluid channels576through the lower plate. The third plurality of fluid channels576may be fluidly isolated from the first and second pluralities of fluid channels.

In operation, the gas distribution assembly may be configured such that two fluids may be delivered into the showerhead from the side, but maintained fluidly separate in two fluidly isolated volumes produced in the assembly. A first fluid may be delivered from above the gas distribution assembly500and may include radical species produced in an RPS or first plasma region, for example. The first fluid may flow through the first plurality of fluid channels561that may be individually isolated and may not be accessed from within the assembly volumes. A second fluid may be introduced into the showerhead from a side port or first delivery channel that delivers the second fluid between the upper plate520and intermediate plate530. The second fluid may flow within this first defined volume and through the second plurality of fluid channels. These channels may also be fluidly isolated from the other channels formed through the assembly. A third fluid may be introduced into the showerhead from an additional side port or second delivery channel that delivers the third fluid between the intermediate plate530and lower plate525. The third fluid may flow within this second defined volume and through the third plurality of fluid channels, which may be fluidly isolated from the other channels formed through the assembly. The additional side port or second delivery channel, as well as the second defined volume, may be fluidly isolated from the first delivery channel and first defined volume. In this way, three fluids may be delivered to a processing region through a single gas distribution assembly, but may be separated until they each exit the gas distribution assembly and enter the processing region.

Although a variety of aperture configurations are encompassed by the disclosed technology,FIGS. 5B and 5Cillustrate two exemplary configurations of fourth apertures567, fifth apertures568, and sixth apertures577. The figures show partial plan views of lower plate525and exemplary orientations of fourth, fifth, and sixth apertures. In some disclosed configurations, the lower plate may include an orientation of fourth, fifth, and sixth apertures such that a majority of fourth apertures567are each surrounded by at least four of the fifth apertures568and four of the sixth apertures577.

As shown inFIG. 5B, fourth apertures567may have four of the fifth apertures568positioned around each of the fourth apertures567. Additionally, four of the sixth apertures577may also be positioned around each of the fourth apertures567. In this configuration, the fifth apertures568a-dmay be located around the fourth apertures567with the centers of the fifth apertures at about 90° intervals from one another as identified about a center of one of the fourth apertures567. Similarly, the sixth apertures577may be located around the fourth apertures with centers of the sixth apertures at about 90° intervals from one another as identified about a center of the fourth apertures577. The sixth apertures577may also be offset from fifth apertures568by about 45° as identified about a center of the fourth apertures577. Each of the fifth apertures568may additionally have four of the sixth apertures577located around the fifth apertures568at about 90° intervals from one another as identified about a center of the fifth apertures568. The apertures may also be considered as rows of apertures based on the fourth apertures567and fifth apertures568. As shown inFIG. 5B, each horizontal row of fourth apertures567or fifth apertures568alternates sixth apertures577with each of the fourth or fifth apertures of the individual rows. The rows are additionally displaced by one aperture in alternating rows, such that each of the fourth or fifth apertures has a located sixth aperture above or below it in each alternating row.

As shown inFIG. 5C, fourth apertures567may have four or more of the fifth apertures568positioned around each of the fourth apertures567. The sixth apertures568may be located in alternating columns with the fourth apertures567. Additionally, six of the sixth apertures577may also be positioned around each of the fourth apertures567. In this configuration, the fifth apertures568may be located around the fourth apertures567with the centers of the fifth apertures at about 60° intervals from one another as identified about a center of the fourth apertures567. Similarly, the sixth apertures577may be located around the fourth apertures with centers of the sixth apertures at about 60° intervals from one another as identified about a center of the fourth apertures577. The sixth apertures577may also be offset from fifth apertures568by about 30° as identified about a center of the fourth apertures577. The fifth apertures568may be located a first radial distance from the center of each of the fourth apertures567. Additionally, the sixth apertures577may be located a second radial distance from the center of each of the fourth apertures567. As illustrated inFIG. 5C, the second radial distance may be less than the first radial distance. Other disclosed embodiments may have the second radial distance greater than the first radial distance. The apertures may again be considered as alternating horizontal rows of apertures of fourth or fifth apertures. As shown in the figure, each fourth or fifth aperture is separated from the next fourth or fifth aperture in a row by two sixth apertures. The rows of apertures may be offset such that each row is displaced by half the distance between any two fourth or fifth apertures such that every other row of apertures is aligned in terms of the sixth apertures577.

In the preceding description, for the purposes of explanation, numerous details have been set forth in order to provide an understanding of various embodiments of the present invention. It will be apparent to one skilled in the art, however, that certain embodiments may be practiced without some of these details, or with additional details.

As used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Thus, for example, reference to “an aperture” includes a plurality of such apertures, and reference to “the plate” includes reference to one or more plates and equivalents thereof known to those skilled in the art, and so forth.

Also, the words “comprise(s)”, “comprising”, “contain(s)”, “containing”, “include(s)”, and “including”, when used in this specification and in the following claims, are intended to specify the presence of stated features, integers, components, or steps, but they do not preclude the presence or addition of one or more other features, integers, components, steps, acts, or groups.