Patent Application
20250054737
Embodiments of the present disclosure generally relate to substrate processing equipment.
In the processing of substrates, such as semiconductor substrates and displays, the substrate is held on a substrate support surface in a processing chamber during processing. The substrate support surface may include an electrostatic chuck (ESC) having one or more electrodes that can be electrically biased to hold a substrate to the substrate support surface. An upper surface of the ESC may have protrusions, or mesas, which form the substrate support surface. The mesas separate the back side of the substrate from the upper surface of the ESC so that backside cooling gas may be delivered to the substrate. However, substrate mesas that are too sparse may lead to overheating of a substrate.
Accordingly, the inventors have provided herein embodiments of improved ESCs.
Embodiments of substrate supports having electrostatic chucks (ESCs) for use in substrate process chambers are provided herein. In some embodiments, a substrate support includes: an electrostatic chuck (ESC) having a top surface and a plurality of mesas extending upward from the top surface, wherein an upper surface of the plurality of mesas define a substrate support surface, wherein a total surface area of the substrate support surface is about 18 to about 40 percent a total surface area of the upper surface, and wherein the ESC includes a plurality of backside gas openings extending through the ESC; and one or more chucking electrodes disposed in the ESC.
In some embodiments, a substrate support includes: an electrostatic chuck (ESC) having a top surface and a plurality of mesas extending upward from the top surface, wherein an upper surface of the plurality of mesas define a substrate support surface, wherein a total surface area of the substrate support surface is 18 percent to about 40 percent of a total surface area of the upper surface, wherein the ESC includes a plurality of lift pin openings, and wherein the ESC includes a plurality of backside gas openings extending through the ESC and terminating on the top surface; and one or more chucking electrodes disposed in the ESC.
In some embodiments, a process chamber includes: a chamber body defining an interior volume therein; and a substrate support disposed in the interior volume, the substrate support comprising: an electrostatic chuck (ESC) having a top surface and a plurality of mesas extending upward from the top surface, wherein an upper surface of the plurality of mesas define a substrate support surface, wherein a total surface area of the substrate support surface is 18 percent to about 40 percent of a total surface area of the upper surface, and wherein the ESC includes a plurality of backside gas openings extending through the ESC; and one or more chucking electrodes disposed in the ESC.
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 substrates supports comprising electrostatic chucks having mesas on an upper surface thereof are provided herein. The mesas advantageously increase cooling of a substrate, such as a glass substrate, and prevent overheating of the substrate. The mesas are configured to provide an increased contact area with the substrate compared with conventional substrate support to increase cooling of the substrate and prevent overheating of the substrate.
A substrate support 124 is disposed within the interior volume 120 to support and retain a substrate 122, such as a glass substrate, a semiconductor wafer, or other such substrate as may be retained. The substrate support 124 may generally comprise a pedestal 150 coupled to a hollow shaft 112. The pedestal 150 comprises an electrostatic chuck (ESC) 152 disposed on a base assembly 136 having a cooling plate 260 (see
The hollow shaft 112 provides a conduit to provide, for example, backside gases, process gases, fluids, coolants, power, or the like, to the pedestal 150. In some embodiments, the hollow shaft 112 is coupled to a lift mechanism 113, such as an actuator or motor, which provides vertical movement of the pedestal 150 between an upper, processing position and a lower, transfer position. A bellows assembly 110 is disposed about the hollow shaft 112 and is coupled between the pedestal 150 and a bottom surface 126 of the process chamber 100 to provide a flexible seal that allows vertical motion of the pedestal 150 while preventing loss of vacuum from within the process chamber 100. The bellows assembly 110 also includes a lower bellows flange 164 in contact with an o-ring 165 or other suitable sealing element which contacts the bottom surface 126 to help prevent loss of chamber vacuum.
The process chamber 100 is coupled to and in fluid communication with a process gas supply 118 which may supply one or more process gases to the process chamber 100 for processing the substrate 122. The interior volume 120 may include a processing volume 119 located in the upper half of the interior volume 120 and generally between the substrate support 124 and the lid 104. The process chamber 100 may also include one or more shields (not shown) circumscribing various chamber components to prevent unwanted reaction between such components and ionized process material. The chamber body 106 may be made of metal, such as aluminum. The chamber body 106 may be grounded via a coupling to ground 115.
In some embodiments, the hollow shaft 112 facilitates coupling a backside gas supply 141, a chucking power supply 140, and RF power sources (e.g., a bias power supply 117) to the pedestal 150. In some embodiments, the bias power supply 117 includes one or more RF bias power sources. In some embodiments, an RF plasma power supply 170 is coupled to the lid 104. In some embodiments, RF energy supplied by the RF plasma power supply 170 may have a frequency of about 400 kHz to over 40 MHz. A plasma 102 may be formed in the interior volume via inductively coupled energy. For example, in some embodiments, the RF plasma power supply 170 is coupled to an antenna assembly or electrode to couple RF energy to a plasma 102 in the interior volume 120. The backside gas supply 141 is disposed outside of the chamber body 106 and supplies heat transfer gas to the pedestal 150. In some embodiments, a bias power supply 117 and the RF plasma power supply 170 are coupled to the pedestal 150 via respective RF match networks (only RF match network 116 shown). In some embodiments, the substrate support 124 may alternatively include AC, DC, or RF bias power. In some embodiments, the AC, DC, or RF bias power may be pulsed.
The process chamber 100 may include a second lift 130. The second lift 130 can include a plurality of lift pins 109 mounted on a platform 108 connected to a shaft 111 which is coupled to a second lift mechanism 132 for raising and lowering the second lift 130. The plurality of lift pins 109 may extend through the ESC 152 so that the substrate 122 may be placed on or removed from the pedestal 150. In some embodiments, each of the lift pins 109 are not mounted to a common platform and are independently controllable. The pedestal 150 may include through holes to receive one or more of the lift pins 109. A bellows assembly 131 is coupled between the second lift 130 and bottom surface 126 to provide a flexible seal which maintains the chamber vacuum during vertical motion of the second lift 130. In some embodiments, as shown in
The pedestal 150 includes gas distribution channels 138 extending, for example, from a lower surface of the pedestal 150 (e.g., bottom surface of the base assembly 136) to various openings in an upper surface of the pedestal 150. The gas distribution channels 138 are configured to provide backside gas, such as nitrogen (N) or helium (He), to the upper surface of the pedestal 150 to act as a heat transfer medium. The gas distribution channels 138 are in fluid communication with the backside gas supply 141 via gas conduit 142 to control the temperature and/or temperature profile of the pedestal 150 during use. The ESC 152 includes a plurality of mesas 188 extending from a top surface of the ESC 152 configured to elevate the substrate 122 slightly above the upper surface to control heat transfer between the ESC 152 and the substrate 122 and disperse the backside gas in a more uniform manner. In some embodiments, the gas distribution channels 138 are configured to provide gas pressure for heat transfer and temperature control of the edge ring 185 independently from a temperature of the ESC 152. In some embodiments, the gas distribution channels 138 extend through the ESC 152 along two or more rings (see
The process chamber 100 is coupled to and in fluid communication with a vacuum system 114 which includes a throttle valve (not shown) and vacuum pump (not shown) which are 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 process chamber 100 includes a slit valve 144 having a substrate transfer opening that is selectively opened or closed to facilitate transferring the substrate 122 into and out of the interior volume 120. In some embodiments, a transfer robot (not shown) having one or more transfer blades is configured to transfer the substrate 122.
In operation, for example, a plasma 102 may be created in the interior volume 120 to perform one or more processes. The plasma 102 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 near or within the interior volume 120 to ignite the process gas and creating the plasma 102. A bias power may be provided from a bias power supply (e.g., bias power supply 117) to the pedestal 150 to attract ions from the plasma 102 towards the substrate 122. The bias power supply 117 may supply bias power to the edge ring 185 and the ESC 152. For example, the bias power supply 117 may comprise a single power supply that is shared by both the edge ring 185 and the ESC 152. Backside gas, or heat transfer gas, may be provided to the substrate 122 via gas conduit 142 to control the temperature and/or temperature profile of the pedestal 150 during use.
The ESC 152 includes a top surface 202 and the plurality of mesas 188 extend upward from the top surface 202. An upper surface 212 of the plurality of mesas 188 define a substrate support surface. In some embodiments, the ESC 152 includes an upper peripheral notch 244 disposed about the top surface 202, to support, for example, the edge ring 185. In some embodiments, the gas distribution channels 138 extend through the base assembly 136 and the ESC 152. The gas distribution channels 138 comprise a plurality of backside gas openings 224 extending through the ESC 152 that are fluidly coupled to the backside gas supply 141.
In some embodiments, a porous plug 230 is disposed in each of the plurality of backside gas openings 224 at an interface between the ESC 152 and the base assembly 136. In some embodiments, a porous plug 232 is disposed in each gas opening 218 of the base assembly 136 opposite each of the plurality of backside gas openings 224. The porous plug 230 and the porous plug 232 are made of a suitable material for providing protection against plasma formation and arcing while providing an adequate flow path for backside gases.
In some embodiments, one or more heating elements 238 are disposed in the ESC 152. The one or more heating elements 238 may comprise any suitable element such as resistive heating elements. In some embodiments, the one or more heating elements 238 are disposed between the one or more chucking electrodes 154 and a bottom surface 240 of the ESC 152. The one or more heating elements 238 may be arranged along one or more separate heating zones. A heater power source 220 may be coupled the one or more heating elements 238 to provide power. In some embodiments, where there is more than one heating zone, the heater power source 220 may be coupled to separate heater terminals coupled to the bottom surface 240, such as two terminals for each heater zone (see
In some embodiments, a total surface area of the substrate support surface defined by the plurality of mesas 188 (i.e., area defined by summation of the upper surface 212 of all mesas of the plurality of mesas 188) is advantageously 18 percent or more of a total surface area of the top surface 202 to provide sufficient contact area to cool the substrate 122. In some embodiments, the total surface area of the substrate support surface is 18 to 40 percent of the total surface area of the upper surface. Such a total surface area advantageously promotes cooling of the substrate 122 via enhanced contact area between the plurality of mesas 188 and the substrate 122 while maintaining adequate spacing on the non-contact areas 310 between adjacent mesas to provide sufficient spread of backside gases throughout the top surface 202. In some embodiments, the plurality of mesas 188 are substantially arranged in an orthogonal grid.
In some embodiments, the plurality of mesas 188 include a plurality of first mesas 330 and a plurality of second mesas 340. The plurality of first mesas 330 are substantially rectangularly shaped and the plurality of second mesas 340 are not rectangularly shaped. In some embodiments, the plurality of first mesas 330 are substantially square shaped and the plurality of second mesas 340 are not square shaped. In some embodiments, the plurality of first mesas are about 0.1 inches to about 0.25 inches wide by about 0.1 inches to about 0.25 inches long.
In some embodiments, the plurality of second mesas 340 comprise a plurality of edges mesas 410 and a plurality of lift pin mesas 338. In some embodiments, substantially all mesas of the plurality of mesas 188 comprise the plurality of first mesas 330. For example, all of the mesas of the plurality of mesas 188 comprise the plurality of first mesas 330 except for some mesas disposed about an outer periphery of the top surface 202 and mesas corresponding to locations of the openings for the plurality of lift pins 109 or the plurality of backside gas openings 224. In some embodiments, the plurality of first mesas 330 are substantially the same in shape and size.
The plurality of lift pin mesas 338 generally correspond with locations of the plurality of lift pin openings 304, for example, proximate the plurality of lift pin openings 304. In some embodiments, a first lift pin of the plurality of lift pin openings 304 extends through a first mesa of the plurality of lift pin mesas 338. In some embodiments, each lift pin opening of the plurality of lift pin openings 304 extends through one of the lift pin mesas of the plurality of lift pin mesas 338. In some embodiments, the plurality of lift pin mesas 338 are larger in size than the plurality of first mesas 330 and the plurality of edge mesas 410. In some embodiments, at least one of the plurality of lift pin mesas 338 includes a rounded portion. In some embodiments, the plurality of lift pin mesas 338 have different shapes and sizes.
As shown in
In some embodiments, the top surface 202 includes a seal ring 420 disposed about the plurality of mesas 188. The seal ring 420 is raised from the top surface 202 at substantially the same height as the plurality of mesas 188 to support an edge of the substrate 122 and to substantially seal the backside gas therein when the substrate 122 is disposed on the pedestal 150.
In some embodiments, the plurality of backside gas openings 224 are disposed in the ESC 152 along one or more annular rings and terminate at the top surface 202 of the ESC 152. For example, as depicted in
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.
