Patent Application
20220093361
Embodiments of the present disclosure generally relate to substrate processing equipment, and more specifically, showerheads for use with substrate processing equipment.
Conventional showerhead assemblies utilized in semiconductor process chambers (e.g., deposition chambers, etch chambers, or the like) typically include a single gas inlet that is fluidly coupled to a plurality of gas outlets to provide multiple gas injection points into a process volume. The multiple gas injection points provide more even flow distribution over a substrate being processed in the process chamber. The inventors have observed that using weldments to split the single gas inlet into the plurality of gas outlets may cause leaking and serviceability issues. In addition, using weldments to split the single gas inlet into the plurality of gas outlets may undesirably increase an overall thickness of the showerhead assembly.
Accordingly, the inventors have provided embodiments of improved showerhead assemblies.
Embodiments of showerheads for use in a substrate processing chamber are provided herein. In some embodiments, a showerhead assembly for use in a substrate processing chamber includes: a chill plate having a plurality of recursive gas paths disposed therein that are fluidly independent from each other and one or more cooling channels disposed therein, wherein each of the plurality of recursive gas paths is fluidly coupled to a single gas inlet extending to a first side of the chill plate and a plurality of gas outlets extending to a second side of the chill plate; and a heater plate coupled to the chill plate, wherein the heater plate includes one or more heating elements disposed therein, a plurality of first gas distribution holes extending from a top surface thereof to a plurality of plenums that are fluidly independent disposed within the heater plate, the plurality of first gas distribution holes corresponding with the plurality of gas outlets of the chill plate, and a plurality of second gas distribution holes extending from the plurality of plenums to a lower surface of the heater plate.
In some embodiments, a showerhead assembly for use in a process chamber includes: a chill plate having one or more cooling channels disposed therein; a heater plate coupled to the chill plate, the heater plate having one or more heating elements embedded therein; and an upper electrode coupled to the heater plate, wherein the showerhead assembly includes a plurality of gas flow paths that are fluidly independent from each other, wherein each of the plurality of gas flow paths extend from a gas inlet on an upper surface of the chill plate to a recursive flow path within the chill plate to a plurality of outlets on a lower surface of the chill plate through a plurality of first gas distribution holes, a plurality of plenums, and a plurality of second gas distribution holes of the heater plate and through a plurality of third gas distribution holes of the upper electrode.
In some embodiments, a process chamber includes: a chamber body defining an interior volume therein; a substrate support disposed in the interior volume to support a substrate; and a showerhead assembly disposed in the interior volume opposite the substrate support, wherein the showerhead assembly comprises: a chill plate having a plurality of recursive gas paths disposed therein that are fluidly independent from each other and one or more cooling channels disposed therein, wherein each of the plurality of recursive gas paths is fluidly coupled to a single gas inlet extending to a first side of the chill plate and a plurality of gas outlets extending to a second side of the chill plate; a heater plate coupled to the chill plate, wherein the heater plate includes one or more heating elements embedded therein, a plurality of first gas distribution holes extending from a top surface thereof to a plurality of plenums that are fluidly independent disposed within the heater plate, the plurality of first gas distribution holes corresponding with the plurality of gas outlets of the chill plate, and a plurality of second gas distribution holes extending from the plurality of plenums to a lower surface of the heater plate; and an upper electrode coupled to the heater plate and having a plurality of third gas distribution holes, each of which are fluidly coupled to one of the plurality of second gas distribution holes of the heater plate.
Other and further embodiments of the present disclosure are described below.
Embodiments of the present disclosure, briefly summarized above and discussed in greater detail below, can be understood by reference to the illustrative embodiments of the disclosure depicted in the appended drawings. However, the appended drawings illustrate only typical embodiments of the disclosure and are therefore not to be considered limiting of scope, for the disclosure may admit to other equally effective embodiments.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The figures are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.
Embodiments of showerhead assemblies for use in a process chamber are provided herein. The showerhead assembly is configured to facilitate a flow of process gas to a substrate being processed within the processing chamber. In some embodiments, the showerhead assembly is configured to operate for high power applications. The showerhead assembly includes a heater plate configured to heat the showerhead assembly. The showerhead assembly includes a chill plate having cooling channels therethrough to cool the showerhead assembly. The showerhead assembly includes one or more recursive gas paths that extend from a single gas inlet to a plurality of gas outlets. In some embodiments, the one or more recursive gas paths are advantageously disposed in the chill plate to minimize a thickness of the showerhead assembly.
The process chamber 100 is a vacuum chamber which is suitably adapted to maintain sub-atmospheric pressures within an interior volume 120 during substrate processing. The process chamber 100 includes a chamber body 106 having sidewalls and a bottom wall. The chamber body 106 is covered by a lid 104 and the chamber body 106 and the lid 104, together, define the interior volume 120. The chamber body 106 and lid 104 may be made of metal, such as aluminum. The chamber body 106 may be grounded via a coupling to ground 115.
A substrate support 124 is disposed within the interior volume 120 to support and retain a substrate 122, such as a semiconductor wafer, for example, or other such substrate as may be electrostatically retained. The substrate support 124 may generally comprise a pedestal 128 and a hollow support shaft 112 for supporting the pedestal 128. The pedestal 128 may include an electrostatic chuck 150. The electrostatic chuck 150 comprises a dielectric plate having one or more electrodes 154 disposed therein. The hollow support shaft 112 provides a conduit to provide, for example, backside gases, process gases, fluids, coolants, power, or the like, to the pedestal 128.
The substrate support 124 is coupled to a chucking power supply 140 and RF sources (e.g., RF bias power supply 117 or RF plasma power supply 170) to the electrostatic chuck 150. In some embodiments, a backside gas supply 142 is disposed outside of the chamber body 106 and supplies heat transfer gas to the electrostatic chuck 150. In some embodiments, the RF bias power supply 117 is coupled to the electrostatic chuck 150 via one or more RF match networks 116. In some embodiments, the substrate support 124 may alternatively include AC or DC bias power.
The process chamber 100 is also coupled to and in fluid communication with a gas supply 118 which may supply one or more process gases to the process chamber 100 for processing the substrate 122 disposed therein. A showerhead assembly 132 is disposed in the interior volume 120 opposite the substrate support 124. In some embodiments, the showerhead assembly 132 is coupled to the lid 104. The showerhead assembly 132 and the substrate support 124 partially define a processing volume 144 therebetween. The showerhead assembly 132 includes a plurality of openings to distribute the one or more process gases from the gas supply 118 into the processing volume 144. The showerhead assembly 132 includes a chill plate 138 to control a temperature of the showerhead assembly 132 and holes/channels (described in more detail below) to provide a gas flow path through the chill plate 138. The showerhead assembly 132 includes a heater plate 141 coupled to the chill plate 138. The heater plate 141 includes one or more heating elements disposed or embedded therein to control a temperature of the showerhead assembly 132 and include holes/channels (described in more detail below) to provide a gas flow path through the heater plate 141. In some embodiments, the showerhead assembly 132 includes an upper electrode 136 coupled to the heater plate 141. The upper electrode 136 is disposed in the interior volume 120 opposite the substrate support 124. The upper electrode 136 is coupled to one or more power sources (e.g., RF plasma power supply 170) to ignite the one or more process gases. In some embodiments, the upper electrode 136 comprises single crystal silicon or other silicon containing material.
A liner 102 is disposed in the interior volume 120 about at least one of the substrate support 124 and the showerhead assembly 132 to confine a plasma therein. In some embodiments, the liner 102 is made of a suitable process material, such as aluminum or a silicon-containing material. The liner 102 includes an upper liner 160 and a lower liner 162. The upper liner 160 may be made of any of the materials mentioned above. In some embodiments, the lower liner 162 is made of the same material as the upper liner 160. In some embodiments, the upper liner 160 includes a stepped inner surface that corresponds with a stepped outer surface 188 of the upper electrode 136.
The lower liner 162 includes a plurality of radial slots 164 arranged around the lower liner 162 to provide a flow path of the process gases to a pump port 148 (discussed below). In some embodiments, the liner 102, along with the showerhead assembly 132 and the pedestal 128, at least partially define the processing volume 144. In some embodiments, an outer diameter of the showerhead assembly 132 is less than an outer diameter of the liner 102 and greater than an inner diameter of the liner 102. The liner 102 includes an opening 105 corresponding with a slit 103 in the chamber body 106 for transferring the substrate 122 into and out of the process chamber 100.
In some embodiments, the liner 102 is coupled to a heater ring 180 to heat the liner 102 to a predetermined temperature. In some embodiments, the liner 102 is coupled to the heater ring 180 via one or more fasteners 158. A heater power source 156 is coupled to one or more heating elements in the heater ring 180 to heat the heater ring 180 and the liner 102.
The process chamber 100 is coupled to and in fluid communication with a vacuum system 114, which includes a throttle valve and a vacuum pump, used to exhaust the process chamber 100. The pressure inside the process chamber 100 may be regulated by adjusting the throttle valve and/or vacuum pump. The vacuum system 114 may be coupled to a pump port 148.
In some embodiments, the liner 102 rests on a lower tray 110. The lower tray 110 is configured to direct a flow of the one or more process gases and processing by-products from the plurality of radial slots 164 to the pump port 148. In some embodiments, the lower tray 110 includes an outer sidewall 126, an inner sidewall 130, and a lower wall 134 extending from the outer sidewall 126 to the inner sidewall 130. The outer sidewall 126, the inner sidewall 130, and the lower wall 134 define an exhaust volume 184 therebetween. In some embodiments, the outer sidewall 126 and the inner sidewall 130 are annular. The lower wall 134 includes one or more openings 182 (one shown in
In operation, for example, a plasma may be created in the processing volume 144 to perform one or more processes. The plasma may be created by coupling power from a plasma power source (e.g., RF plasma power supply 170) to a process gas via one or more electrodes (e.g., upper electrode 136) near or within the interior volume 120 to ignite the process gas and create the plasma. A bias power may also be provided from a bias power supply (e.g., RF bias power supply 117) to the one or more electrodes 154 within the electrostatic chuck 150 to attract ions from the plasma towards the substrate 122.
A plasma sheath can bend at an edge of the substrate 122 causing ions to accelerate perpendicularly to the plasma sheath. The ions can be focused or deflected at the substrate edge by the bend in the plasma sheath. In some embodiments, the substrate support 124 includes an edge ring 146 disposed about the electrostatic chuck 150. In some embodiments, the edge ring 146 and the electrostatic chuck 150 define a substrate receiving surface. The edge ring 146 may be coupled to a power source, such as RF bias power supply 117 or a second RF bias power supply (not shown) to control and/or reduce the bend of the plasma sheath.
The chill plate 138 includes a plurality of recursive gas paths 206 disposed therein that are fluidly independent from each other and corresponding to the two or more gas zones of the showerhead assembly 132. For example, the plurality of recursive gas paths 206 may comprise two, three, or four recursive gas paths (two recursive gas paths depicted in
In some embodiments, the plurality of recursive gas paths 206 are disposed about the chill plate 138 along a common plane (i.e., a single layer). In some embodiments, at least one of the plurality of recursive gas paths 206 are disposed about the chill plate 138 along two or more planes (i.e., two or more layers), where connecting channels (such as connecting channels 220) couple multiple layers of the plurality of recursive gas paths 206. The two or more layers advantageously allow for increased volume for the plurality of recursive gas paths 206 to extend within the chill plate 138 as compared to a single layer.
In some embodiments, the chill plate 138 comprises one or more plates coupled together. As depicted in
In some embodiments, a first gas inlet 212 extends from the first side 218 of the chill plate 138 (i.e., upper surface of top plate 228) to a first recursive gas path 310 (see
In some embodiments, each of the plurality of recursive gas paths 206 are coupled to the gas supply 118. The gas supply can be configured to provide one or more process gases to any one or more of the recursive gas paths. For example, in some embodiments, the gas supply 118 is configured to provide a single process gas to each of the recursive gas paths 310, 330). In some embodiments, the gas supply 118 is configured to provide a first process gas or gaseous mixture to one or more of the recursive gas paths 310, 330 and a second process gas or gaseous mixture to a remainder of the recursive gas paths 310, 330. In some embodiments, the gas supply 118 is configured to provide different process gases or gaseous mixtures to each of the recursive gas paths.
The heater plate 141 includes one or more heating elements 208. In some embodiments, the heater plate 141 includes a plurality of first gas distribution holes 252 extending from a top surface 250 thereof to a plurality of plenums 256 that are fluidly independent and disposed in the heater plate 141. A plurality of second gas distribution holes 254 extend from the plurality of plenums 256 to a lower surface 258 of the heater plate to provide a gas flow path through the heater plate 141. In some embodiments, the plurality of second gas distribution holes 254 comprises more holes than the plurality of first gas distribution holes 252 to more uniformly disperse the one or more process gases into the processing volume 144.
The plurality of first gas distribution holes 252 are aligned with the plurality of gas outlets 248 of the chill plate 138. In some embodiments, the plurality of plenums 256 correspond with the plurality of recursive gas paths 206. In some embodiments, the showerhead assembly 132 includes the upper electrode 136 coupled to the heater plate 141. The upper electrode 136 includes a plurality of third gas distribution holes 274 extending from a top surface 276 thereof at locations corresponding to locations of the plurality of second gas distribution holes 254 of the heater plate 141 to a lower surface 278 of the upper electrode 136. In some embodiments, the plurality of third gas distribution holes 274 have a diameter of about 10 mils to about 50 mils. The upper electrode 136, the heater plate 141, and the chill plate 138 may be coupled together via fasteners, spring tensioners, or the like.
In some embodiments, each of the plurality of gas flow paths through the showerhead assembly 132 that are fluidly independent from each other extends through the chill plate 138 via a respectively gas inlet on the first side 218 of the chill plate 138 to a recursive flow path within the chill plate 138 to a respective plurality of gas outlets 248 that extend to the second side 224 of the chill plate 138, through the heater plate 141 via respective holes of the plurality of first gas distribution holes 252, a respective plenum of the plurality of plenums 256, and respective holes of the plurality of second gas distribution holes 254, and through the upper electrode 136 via the plurality of third gas distribution holes 274. For example, a first gas flow path extends from the plurality of gas outlets 248 associated with the first recursive gas path 410 through corresponding ones of the first gas distribution holes 252 and into a first plenum of the plurality of plenums 256. Similarly, a second gas flow path extends from the plurality of gas outlets 248 associated with the second recursive gas path 330, through corresponding ones of the first gas distribution holes 252 and into a second plenum of the plurality of plenums 256.
In some embodiments, the heater plate 141 comprises one or more plates coupled together. In some embodiments, the heater plate 141 includes a first plate 262 coupled to a second plate 264. The one or more heating elements 208 are disposed in a plurality of channels 268. In some embodiments, the plurality of channels 268 are disposed in the first plate 262. In some embodiments, the plurality of channels 268 are disposed in the second plate 264. In some embodiments, the plurality of channels 268 are defined by both the first plate 262 and the second plate 264. In some embodiments, the first plate 262 and the second plate 264 both include the plurality of channels 268. In some embodiments, a third plate 266 is coupled to the second plate 264 on a side of the second plate 264 opposite the first plate 262. In some embodiments, the third plate 266 includes a second plurality of channels 272 that define the plurality of plenums 256.
In some embodiments, a first thermal gasket sheet 280 is disposed between the chill plate 138 and the heater plate 141 to provide enhanced thermal coupling therebetween and a compression interface. In some embodiments, a second thermal gasket sheet 282 is disposed between the heater plate 141 and the upper electrode 136 to provide enhanced thermal coupling therebetween and a compression interface. The first thermal gasket sheet 280 includes a plurality of openings corresponding with locations of the plurality of first gas distribution holes 252 of the heater plate 141. The second thermal gasket sheet 282 includes a plurality of openings corresponding with locations of the plurality of second gas distribution holes 254 of the heater plate 141. The first thermal gasket sheet 280 and the second gasket sheet 281 are made of a thermally and electrically conductive sheet of material. In some embodiments, the first thermal gasket sheet 280 and the second gasket sheet 281 comprise a polymer material. In some embodiments, the first thermal gasket sheet 280 and the second gasket sheet 281 comprise an elastomer and metal sandwich structure.
Each of the plurality of recursive gas paths 206 may be disposed in at least one of the first layer 300 and the second layer 400. In some embodiments, one or more of the plurality of recursive gas paths 206 extend from the second layer 400 to the first layer 300 and back to the second layer 400. In some embodiments, the first gas inlet 212 extends to the first layer 300 and is fluidly coupled to a first recursive gas path 310 disposed in both the first layer 300 and the second layer 400. In some embodiments, the first recursive gas path 310 branches out from the first gas inlet 212 one or more times in the first layer 300 to a plurality of ends corresponding with connecting channels 220A that fluidly couple the multiple layers of the first recursive gas path 310. In some embodiments, the first recursive gas path 310 branches out one time to two ends corresponding with two connecting channels 220A.
In some embodiments, in the second layer 400, the first recursive gas path 310 branches out one or more times from each of the connecting channels 220A to a plurality of first ends 415. In some embodiments, the first recursive gas path 310 branches out once from each connecting channel 220A in the second layer 400 to form four first ends 415. In some embodiments, the plurality of first ends 415 are symmetrically disposed about the gas plate 230. In some embodiments, the plurality of first ends 415 lie at regular intervals along an imaginary circle. In some embodiments, the first recursive gas path 310 includes annular extending portions and radial extending portions in the second layer 400. The plurality of second ends 435 are aligned with a first subset 248A of the plurality of gas outlets 248 of the chill plate 138. In some embodiments, the first recursive gas path 310 branches out two times from each connecting channel 220A in the second layer 400 to form eight first ends 415.
In some embodiments, a second recursive gas path 330 extends from the second gas inlet 216 to the second layer 400, to the first layer 300, and then back to the second layer 400. As such, the second recursive gas path 330 may be disposed in both the first layer 300 and the second layer 400. In some embodiments, the second recursive gas path 330 branches out from the second gas inlet 216 one or more times in the second layer 400 to a plurality of ends corresponding with connecting channels 220C that fluidly couple the multiple layers of the second recursive gas path 330. In some embodiments, the second recursive gas path 330 branches out once to form two ends corresponding with two connecting channels 220C.
In some embodiments, in the first layer 300, the second recursive gas path 330 branches out one or more times from each of the connecting channels 220C to ends corresponding with connecting channels 220D. In some embodiments, the second recursive gas path 330 branches out one time from each of the connecting channels 220C to form four ends corresponding with four connecting channels 220D.
In some embodiments, in the second layer 400, the second recursive gas path 330 branches out one or more times from each of the connecting channels 220D to a plurality of second ends 435. In some embodiments, the second recursive gas path 330 branches out once from each connecting channel 220D in the second layer 400 to form a total of eight second ends 435. In some embodiments, the plurality of second ends 435 are symmetrically disposed about the gas plate 230. In some embodiments, the plurality of second ends 435 are disposed at regular intervals along an imaginary circle. In some embodiments, the second recursive gas path 330 includes annular extending portions and radial extending portions in the second layer 400. The plurality of second ends 435 are aligned with a second subset 248B of the plurality of gas outlets 248 of the chill plate 138. In some embodiments, the second recursive gas path 330 is disposed radially outward from the first recursive gas path 310. In some embodiments, the second recursive gas path 330 branches out twice from each connecting channel 220D in the second layer 400 to form sixteen second ends 435.
In some embodiments, the one or more cooling channels 204 includes one cooling channel having an inlet 510 for supplying a coolant therethrough and an outlet 520 to provide a return path for the coolant. In some embodiments, the one or more cooling channels 204 extend proximate each zone. In some embodiments, the one or more cooling channels 204 are arranged in a spiral pattern.
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.
