Gas ring with stacked recursive ring layers

Abstract

A gas ring comprises a bottom ring layer, a plurality of intermediate ring layers stacked above the bottom ring layer, and a top ring layer disposed above the plurality of intermediate ring layers. A bottom ring layer comprise a first gas channel and a bottom gas inlet. Intermediate ring layers are bonded to the bottom ring layer and to each other, and each intermediate ring layer comprises a number of gas channels that is twice a number of gas channels of an adjacent lower ring layer, and each gas channel of the adjacent lower ring layer is coupled to two gas channels of the intermediate ring layer. The top ring layer is bonded to an adjacent intermediate ring layer of the plurality of intermediate ring layers and comprises a plurality of gas outlets.

Description

Attorney Docket No.: 28245.1257 (L1257PCT)GAS RING WITH STACKED RECURSIVE RING LAYERSTECHNICAL FIELD

[0001] Embodiments of the disclosure relate, in general, to systems and methods for delivering a process gas to an edge of a substrate in a process chamber. Some embodiments relate to a near-wafer gas ring with stacked recursive ring layers, which may be a component in a gas delivery system for delivering a process gas to an edge of a substrate.BACKGROUND

[0002] An electronic device manufacturing system can include a process chamber, in which a process gas can be delivered to a substrate disposed within the process chamber. A process chamber may have nozzles embedded in its ceiling and / or side walls, through which a process gas may be flowed. A process chamber may additionally have a substrate support assembly, on which the substrate is placed.SUMMARY

[0003] In some embodiments, a gas ring may comprise a bottom ring layer, a plurality of intermediate ring layers, and a top ring layer. The bottom ring layer may comprise a first gas channel and a bottom gas inlet. The plurality of intermediate ring layers may be stacked on each other above the bottom ring layer and may be bonded to the bottom ring layer and to each other. Each intermediate ring layer of the plurality of intermediate ring layers may comprise a number of gas channels that is twice a number of gas channels of an adjacent lower ring layer, and each gas channel of the adjacent lower ring layer may be coupled to two gas channels of the intermediate ring layer. The top ring layer may be disposed above the plurality of intermediate ring layers and bonded to an adjacent intermediate ring layer of the plurality of intermediate ring layers, and the top ring layer may comprise a plurality of gas outlets.

[0004] In some embodiments, a gas delivery system may comprise a gas ring as set forth in the present disclosure, a cathode sleeve, a process kit ring, and a gas line. The gas ring may encircle and be coupled to a substrate support, and the substrate support may be configured to support a substrate that is to receive delivery of gas during processing. The cathode sleeve may horizontally encircle the gas ring without vertically enclosing the gas ring. A process kit ring may be disposed above the gas ring and comprise a plurality of gas delivery holes. A gas line may be connected to the bottom gas inlet of the gas ring.Attorney Docket No.: 28245.1257 (L1257PCT)

[0005] In some embodiments, a method may comprise bonding a bottom ring layer, bonding a plurality of intermediate ring layers, and bonding a top ring layer of a gas ring together to form a gas ring as set forth in the present disclosure. Bonding a bottom ring layer may comprise bonding a bottom ring layer of a gas ring to a first adjacent intermediate ring layer of a plurality of intermediate ring layers of the gas ring by a fusing process. Bonding a plurality of intermediate ring layers may comprise bonding a plurality of intermediate ring layers stacked above the bottom ring layer to each other by the fusing process. Bonding a top ring layer of the gas ring may comprise bonding the top ring layer to a second adjacent intermediate ring layer of the plurality of the intermediate ring layer by the fusing process. The bottom ring layer may be configured to receive a process gas at a bottom gas inlet, and the top ring layer may be configured to output the process gas at a plurality of gas outlets to provide a uniform gas flow distribution near an edge of a substrate.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that different references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. The elements in the figures and accompanying drawings are not drawn to scale. The relative scale of the elements in the drawings may have been altered to enhance the visibility of the individual elements, and the scale as depicted in the drawings is not limiting.

[0007] FIG. 1 depicts a cross-sectional view of one embodiment of a process chamber comprising a gas delivery system, the gas delivery system comprising a gas ring, in accordance with some embodiments.

[0008] FIG. 2A depicts a horizontal view of a gas ring comprising a bottom ring layer, a plurality of intermediate ring layers, and a top ring layer, in accordance with some embodiments.

[0009] FIG. 2B depicts a top-down cross-sectional view of a bottom ring layer of a gas ring, in accordance with some embodiments.

[0010] FIG. 2C depicts a top-down cross-sectional view of a first intermediate ring layer of a gas ring, in accordance with some embodiments.

[0011] FIG. 2D depicts a top-down cross-sectional view of a second intermediate ring layer of a gas ring, in accordance with some embodimentsAttorney Docket No.: 28245.1257 (L1257PCT)

[0012] FIG. 2E depicts a top-down view of a gas ring, in accordance with some embodiments.

[0013] FIG. 2F depicts a perspective view of a gas ring, in accordance with some embodiments.

[0014] FIG. 2G depicts an exploded view of a gas ring, in accordance with some embodiments.

[0015] FIG. 2H depicts a perspective view of a recursive gas path network within a gas ring, in accordance with some embodiments.

[0016] FIG. 3 is a flow chart of an example method for delivering a process gas to an edge of a wafer using the gas ring, in accordance with some embodiments.

[0017] FIG. 4 is a flow chart of an example method for fabricating a gas ring, in accordance with some embodiments.DETAILED DESCRIPTION

[0018] In substrate manufacturing, a substrate (e.g., such as a wafer) may be processed in a process chamber by exposure to a process gas delivered by a gas delivery system of the chamber. Examples of processes that may be performed may include a deposition process or an etch process. Gas delivery systems for process chambers may provide process gases from a ceiling and / or from side walls of the process chamber. In some gas delivery systems, a center of the substrate may receive a different rate of gas flow from an edge of the substrate, resulting in an uneven finish (e.g., an uneven film thickness and / or other uneven film properties) from the center of the substrate to the edge of the substrate. In some gas delivery systems, a process gas may be directly delivered to the edge of the substrate by a series of recursive stainless steel tubes. The recursive stainless steel tubes may provide a nonuniform rate of gas flow along an edge of a substrate, resulting in an uneven finish along the edge of the substrate. Additionally, stainless steel may be susceptible to corrosion and erosion by a plasma and / or a process gas and may undergo anodization or the addition of protective coatings to prevent erosion or corrosion. Additionally, the use of recursive stainless steel gas delivery tubes takes up significant volume within the process chamber and limits the number of recursions of the stainless steel gas delivery tubes that are achievable, reducing an overall uniformity that is achievable at the edge of the substrate.

[0019] To address at least the above-noted drawbacks, embodiments described herein provide for a gas ring (e.g., a near-wafer gas ring) with stacked recursive ring layers, as well as systems and methods for using the gas ring to provide a uniform delivery of a process gas toAttorney Docket No.: 28245.1257 (L1257PCT)an edge of a substrate. In embodiments, a gas delivery system may comprise a gas ring with stacked recursive layers. The gas ring may be configured to provide an even gas distribution about the circumference of a substrate encircled by the gas ring when a process gas is flowed through the gas ring. The embodiments described herein can allow a gas flow distribution of a process gas near an edge of a substrate to be uniform during an execution of a process, which may be an etch process or a deposition in examples.

[0020] In embodiments, a gas ring may comprise a bottom ring layer, and the bottom ring layer may comprise a first gas channel and a bottom gas inlet. In embodiments, a first gas channel may have a length approximately equal to half of the circumference of the bottom ring layer. In one embodiment, the first gas channel may have a width of between 30 and 60 mils (approximately 0.76-1.52 mm). In embodiments, the bottom gas inlet may be located on the midpoint of the first gas channel, such that two endpoints of the first gas channel are equidistant from the location of the bottom gas inlet, and a first gas velocity at a first endpoint is equal to a second gas velocity at a second endpoint during a flowing of a process gas. In embodiments, each endpoint of the first gas channel may be the location of an intermediate gas outlet.

[0021] A gas ring may further comprise a plurality of intermediate ring layers stacked and bonded to the bottom ring layer and to each other. In embodiments, each ring layer of the plurality of intermediate ring layers comprises a number of gas channels that is twice the number of gas channels of an adjacent lower ring layer, and each gas channel of the adjacent lower ring layer is coupled to two gas channels of the intermediate ring layer. In embodiments, each endpoint of a gas channel of a intermediate ring layer may be a location of an intermediate gas outlet. In embodiments, an intermediate gas outlet of an adjacent lower ring layer may be coupled to an intermediate gas inlet located at a midpoint of a gas channel of an intermediate ring layer disposed directly above the adjacent lower ring layer. When a process gas enters the gas channel of the intermediate ring layer through the intermediate gas inlet, a first gas velocity at a first endpoint of the gas channel of the intermediate ring layer may be equal to a second gas velocity of a second endpoint of the gas channel. In embodiments, each gas channel of an intermediate ring layer may be equal in length. In some embodiments, the total length of all gas channels of an intermediate ring layer may be approximately equal to half of the circumference of the intermediate ring layer. Each gas channel of an intermediate ring layer may be equal in width, height, and / or diameter, and a width, height and / or diameter of a gas channel of the intermediate ring layer may be lesser than that of a width, height and / or diameter of a gas channel of an adjacent lower ring layer.Attorney Docket No.: 28245.1257 (L1257PCT)In one embodiment, a gas channel diameter of a bottom ring layer is greater than a gas channel diameter of one or more intermediate ring layers, which may be greater than a gas channel diameter of a top ring layer. In one embodiment, the bottom ring layer has gas channels with a

[0022] A reduction in width, height and / or diameter of a gas channel may reduce a gas flow area for an intermediate ring layer, and the width, height and / or diameter of a gas channel of an intermediate ring layer may thus be adjusted to control a gas flow velocity under a target gas flow pressure. In embodiments, the width, height and / or diameter of a first gas channel of a bottom ring layer may be greater than that of every gas channel of each intermediate ring layer of a plurality of ring layers, such that a gas flow velocity in a gas channel of an intermediate ring layer is greater than a gas flow velocity in an inlet of the bottom ring layer.

[0023] A gas ring may further comprise a top ring layer disposed above the plurality of intermediate ring layers and bonded to an uppermost intermediate ring layer. The top ring layer may comprise a plurality of gas outlets, which may connect to a process kit ring of the gas delivery system. In some embodiments, a number of gas outlets of the top ring layer may be twice a number of gas channels of an uppermost intermediate ring layer. Each gas channel of the uppermost intermediate ring layer may be coupled to two gas outlets of the top ring layer, and a gas outlet of the top ring layer may be disposed directly above an endpoint of a gas channel of the uppermost intermediate ring layer. In embodiments, each gas flow path of a plurality of gas flow paths from a bottom gas inlet to each gas outlet of the top ring layer is equal in length, such that a gas velocity and a gas flow rate through each gas outlet of the top ring layer is equal when a process gas is flowed through the gas ring.

[0024] FIG. 1 depicts a cross-sectional view of one embodiment of a process chamber 100 comprising a gas delivery system 101, the gas delivery system comprising a gas ring 150. In embodiments, the process chamber 100 may comprise a chamber volume 104 enclosed by chamber walls 103. In some embodiments, process chamber 100 may be enclosed by a lid 106. The process chamber 100 may further comprise a gas delivery system 101 supported by a bottom plate 102. The gas delivery system 101 may be a near-substrate gas delivery system, which may be accompanied in the process chamber with one or more additional gas delivery systems (e.g., a top gas delivery system including a ceiling nozzle 113 and / or a side gas delivery system including a side wall nozzle 114).

[0025] In embodiments, the process chamber 100 comprises a load port 105 through chamber walls 103, through which a substrate 152 may be placed on a substrate support assembly 109 that may be integrated with gas delivery system 101. The load port 105 may be designed toAttorney Docket No.: 28245.1257 (L1257PCT)permit an end effector of a robotic arm to access a substrate 152 disposed on the substrate support assembly 109.

[0026] A first gas source 111 may be coupled to the gas delivery system 101 and provide a process gas to be delivered to the substrate 152 (e.g., to an edge of the substrate 152). In embodiments, a process gas from first gas source 111 is delivered through gas ring 150 to a process kit ring 142, that is to deliver the process gas to an edge of the substrate 152 placed on the substrate support assembly 109. In embodiments, the substrate 152 may be encircled by the gas ring 150.

[0027] Process chamber 100 may also comprise a second gas source 112, which may be coupled to one or more other gas delivery systems comprising one or more gas nozzles. In embodiments, second gas source 112 may be coupled to a ceiling nozzle 113 and / or a side wall nozzle 114. The ceiling nozzle 113 and the side wall nozzle 114 may be embedded in chamber walls 103 and / or lid 106 in embodiments. In embodiments where process chamber 100 comprises a lid 106, a ceiling nozzle 113 may be embedded in the lid 106 instead of or in addition to in chamber walls 103.

[0028] Second gas source 112 may provide a process gas to ceiling nozzle 113 and / or side wall nozzle(s) 114, through which the process gas flows into a chamber volume 104. The process gas provided by the second gas source 112 may be the same gas or a different gas from the gas provided by a first gas source 111. In some embodiments, a same gas source is connected to ceiling nozzle 113, side wall nozzle(s) 114 and / or gas delivery system 101. In embodiments, process gases flowed into a process chamber 101 may be or include a process gas for etching a substrate or a process gas for depositing a layer on a substrate. In some embodiments, process chamber 100 may comprise an exhaust port 120, which may be coupled with a pump to remove an effluent gas from process chamber 100.

[0029] Process chamber 100 may further comprise a plasma source 130 that may energize the process gases in the chamber volume 104. In some embodiments, the plasma source 130 may comprise radio frequency (RF) coils configured to energize a process gas to be flowed into chamber volume 104. In some embodiments, plasma source 130 may be disposed in the chamber walls 103. In other embodiments where process chamber 100 comprises a lid 106, plasma source 130 may be disposed along the lid 106. In some embodiments, plasma source 130 is a remote plasma source. In some embodiments, plasma source 130 is a charge coupled plasma source. In some embodiments, plasma source 130 is an inductively coupled plasma source.Attorney Docket No.: 28245.1257 (L1257PCT)

[0030] In embodiments, an insulator ring 145 may be disposed below the gas ring 150 and horizontally encircled by gas ring 150. In embodiments, a substrate support 146 may be disposed within a cavity formed by insulator ring 145 and gas ring 150. Substrate support 146 may be encircled by the gas ring 150 and may be configured to support a substrate 152 that is to receive delivery of gas from the top ring layer of the gas ring 150 and / or from a process kit ring 142 that received process gas from the gas ring 150 during processing. The substrate support 146 may be any device known in the prior art to be suitable for holding a substrate during an execution of a process in a process chamber. In some embodiments, the substrate support 146 may comprise an electrostatic chuck.

[0031] In embodiments, the insulator ring 145 and the gas ring 150 may be disposed above a ground plate 144. In embodiments, the gas ring 150 may be disposed above a cathode chassis 141. Gas ring 150 may not be in direct contact with the cathode chassis 141 and may be physically separated from cathode chassis 141 by a ground plate 144 in embodiments. In embodiments, the gas delivery system 101 may comprise a cathode sleeve 143 that horizontally encircles the gas ring 150. The cathode sleeve 143 may further horizontally encircle the insulator ring 145 and the ground plate 144 and may be in contact with the cathode chassis 141. In one embodiment, cathode sleeve 143 horizontally encircles an upper portion of the cathode chassis 141.

[0032] In embodiments, a gas line 170 may be embedded within cathode chassis 141. In one embodiment, gas line 170 may be a tube constructed from stainless steel. In other embodiments, the gas line 170 may be constructed from any materials known in the art to be suitable for transporting a process gas. Gas line 170 may be provided with a process gas by a first gas source 111 and be terminated with a gas nozzle 171. In one embodiment, gas nozzle 171 may be constructed from stainless steel. Gas nozzle 171 may be coupled to an inlet 203 of the gas ring 150.

[0033] Gas delivery system 101 may further comprise a process kit ring 142, which may be vertically disposed above the gas ring 150. Process kit ring 142 may be configured to receive a process gas from a top ring layer of gas ring 150 and may comprise a plurality of gas delivery holes through which the process gas may be delivered to an edge of a substrate (e.g., such as a wafer) through process kit ring 142. The plurality of delivery holes may be connected to a plurality of gas outlets of a top ring layer of gas ring 150. In one embodiment, a number of delivery holes of the process kit ring 142 may be twice that of a number of gas outlets of the top ring player of the gas ring 150. In one embodiment, a number of delivery holes of the process kit ring 142 is equal to a number of gas outlets of the top ring layer of theAttorney Docket No.: 28245.1257 (L1257PCT)gas ring 150. Each gas outlet of the top ring layer of the gas ring 150 may be connected to one or two delivery holes of process kit ring 142 in embodiments. In embodiments, each delivery hole of process kit ring 142 may be connected to a respective single gas outlet of the top ring layer.

[0034] In embodiments, process kit ring 142 may not be bonded to gas ring 150 and may be removable. In one embodiment, gas delivery system 101 may initially comprise a first process kit ring which may be replaced by a second process kit ring. The first process kit ring may have a first plurality of delivery holes at a first diameter. The second process kit ring may have a second plurality of delivery holes at a second diameter, which may be greater or lesser than the first diameter. The first process kit ring may be initially disposed above the gas ring, and the first process kit ring may be removed and replaced with the second process kit ring. By changing the process kit ring, the diameters and / or positions of the process holes, gas delivery holes, etc. may be adjusted, which may adjust a gas velocity and / or distribution at an edge of a substrate. For example, if the second diameter is lesser than the first diameter, a gas velocity at the edge of a substrate may be increased, as gas velocity may be inversely proportional to a gas flow area. Conversely, if the second diameter is greater than the first diameter, a gas velocity at an edge of a substrate may be reduced.

[0035] FIG. 2A is a side view of gas ring 150, which may comprise a bottom ring layer 201, a plurality of intermediate ring layers 210, and a top ring layer 221. In one embodiment, the bottom ring layer 201 may comprise a first gas channel and an inlet 203, which may receive a flow of a process gas from first gas source 111. In one embodiment, the plurality of intermediate ring layers may comprise a first intermediate ring layer 211, a second intermediate ring layer 212, a third intermediate ring layer 213, a fourth intermediate ring layer 214, and a fifth intermediate ring layer 215. The first intermediate ring layer 211 may be disposed above and permanently bonded to the bottom ring layer 201. The other intermediate ring layers may be stacked above first intermediate ring layer 211 and each other, and the plurality of intermediate ring layers 210 may be permanently bonded to each other.

[0036] In some embodiments, a bottom ring layer 201, an intermediate ring layer of a plurality of intermediate ring layers 210, and / or a top ring layer 221 may have a diameter between 150-600 millimeters. In one embodiment, a bottom ring layer 201, a first intermediate ring layer 211, a second intermediate ring layer 212, and a third intermediate ring layer 213 each have a diameter of 300-400 millimeters. A fourth intermediate layer 214 in this embodiment has a lower portion with a diameter of 300-400 millimeters, and an upper portion with a diameter of 300-400 millimeters. In this embodiment, a fifth intermediate ringAttorney Docket No.: 28245.1257 (L1257PCT)layer 215 and an upper ring layer 221 may each have a diameter of 300-400 millimeters. In some embodiments, a bottom ring layer 201, an intermediate ring layer of the plurality of intermediate ring layers 210, and / or a top ring layer may have a height between 5 and 20 millimeters. In one embodiment, a bottom ring layer, a first intermediate ring layer, a second intermediate ring layer, a third intermediate ring layer, a fourth intermediate ring layer, and / or a fifth intermediate ring layer, are each approximately the same height, and have a total height of 80-120 mm (e.g., about 90 millimeters) when stacked as a gas ring. In one embodiment, a gas channel diameter of a bottom ring layer is greater than a gas channel diameter of one or more intermediate ring layers, which may be greater than a gas channel diameter of a top ring layer. In one embodiment, the bottom ring layer has gas channels with a diameter of about 5-6 mm. In one embodiment, an intermediate ring layer adjacent to the bottom ring layer and optionally one or more additional lower intermediate ring layers have gas channels with a diameter of about 2-3 mm. In one embodiment, a top ring layer has gas outlets with a diameter of about 1-2 mm. In one embodiment, an intermediate ring layer adjacent to the top ring layer, and optionally one or more additional intermediate ring layers have gas channels with a diameter of about 1-2 mm.

[0037] Each intermediate ring layer of the plurality of intermediate ring layers 210 may comprise a number of gas channels that is twice a number of gas channels of an adjacent lower ring layer in embodiments. A number of intermediate ring layers 210 may depend on a number of gas delivery holes or channels ultimately targeted for the top ring layer of the gas ring. Each subsequent gas ring layer may have twice the number of outlet gas delivery holes or channels as a previous gas ring layer in embodiments. In one embodiment, a gas ring 150 comprises five intermediate ring layers. A first intermediate ring layer 211 may comprise two gas channels. A second intermediate ring layer 212 may comprise four gas channels. A third intermediate ring layer 213 may comprise eight gas channels. A fourth intermediate ring layer 214 may comprise sixteen gas channels. A fifth intermediate ring layer 215 may comprise thirty-two ring layers. In some embodiments, the plurality of intermediate ring layers may comprise more or less than five intermediate ring layers, and a nth intermediate ring layer may comprise 2” gas channels.

[0038] A top ring layer 221 may be disposed above and permanently bonded to the uppermost intermediate ring layer of the plurality of intermediate ring layers 210. In one embodiment, the plurality of intermediate ring layers 210 may comprise five intermediate ring layers, and the top ring layer 221 may be disposed above and permanently bonded to a fifth intermediate ring layer 215. The top ring layer 221 may comprise a plurality of gasAttorney Docket No.: 28245.1257 (L1257PCT)outlets, each of which may be connected to a gas channel of the uppermost ring layer of the plurality of intermediate ring layers 210. In some embodiments, the number of gas outlets of the plurality of gas outlets may be twice a number of gas channels of the uppermost ring layer or equal to a number of gas channels of the uppermost ring layer. In some embodiments, each gas channel of the uppermost ring layer may be connected to two gas outlets of the top ring layer. In one embodiment, the plurality of ring layers 210 comprises five intermediate ring layers, an uppermost intermediate ring layer is a fifth intermediate ring layer 215 comprising thirty-two gas channels, and the top ring layer 221 comprises sixty-four gas outlets. In embodiments, the sixty-four gas outlets may be of an equal diameter, and each gas outlet may have an equal gas flow velocity and an equal gas flow rate when a process gas is flowed into an inlet 203 of the gas ring 150.

[0039] In some embodiments, one or more ring layers of the gas ring 150 may be fabricated from a material that is resistant to corrosion or erosion caused by contact with a plasma or a process gas. In embodiments, one or more ring layers of the gas ring 150 may comprise a ceramic, which may be aluminum nitride or aluminum oxide, for example. In another embodiment, one or more ring layers of the gas ring 150 may comprise quartz.

[0040] FIG. 2B is a top-down cross-sectional view of bottom ring layer 201, which may comprise a first gas channel 202 having two ends 205 A-B (which may correspond to intermediate gas outlets), a bottom gas inlet 203, and two intermediate gas outlets 205 A-B. The first gas channel 202 may be coupled through the bottom gas inlet 203 to a gas nozzle 171 of a gas line 170, which may flow a process gas from a first gas source 111. The ends 205 A-B of the first gas channel 202 may be connected to two intermediate gas inlets of an adjacent intermediate ring layer. In embodiments, the length of the first gas channel 202 may be approximately equal to half the circumference of the bottom ring layer 201. The bottom gas inlet 203 may be located at a midpoint of the first gas channel 202, such that when a process gas is flowed into the first gas channel 202, each intermediate gas outlet 205 A-B disposed at endpoints of the first gas channel 202 has an equal gas flow rate and gas flow velocity. In some embodiments, a bottom gas inlet 203 may have a diameter between 1-10 millimeters. In one embodiment, the bottom gas inlet 203 may have a diameter of 5.33 millimeters. In some embodiments, the first gas channel 202 is in an interior of the bottom ring layer 201 (e.g., such that the first gas channel 202 is covered by a top of the bottom ring layer. In some embodiments, the first gas channel 202 is formed in a top surface of the bottom ring layer 201 (e.g., such that the first gas channel 202 is open to the top of the bottom ring layer 201).Attorney Docket No.: 28245.1257 (L1257PCT)

[0041] FIG. 2C is a top-down cross-sectional view of first intermediate ring layer 211, which may comprise a plurality of gas channels. In embodiments, each gas channel of the plurality of gas channels of the intermediate ring layer 211 may comprise or be connected to a respective intermediate gas inlet 241 A-B and terminate at a pair of ends 251 A-D (and optionally at a pair of intermediate gas outlets). In some embodiments, a first intermediate gas inlet 241 A may couple a second gas channel 231 A to a first end 205 A of the first gas channel 202 of the bottom ring layer 201, which the first intermediate ring layer 211 may be disposed immediately above. In embodiments, first intermediate ring layer 211 may comprise two gas channels, each of which comprises an intermediate gas inlet. A first intermediate gas inlet 241 A may be located at a midpoint of a second gas channel 231 A and connect to an end 205A of the first gas channel 202. In some embodiments, a first intermediate gas inlet 241 A may have a diameter between 1-5 millimeters, and the diameter of the first intermediate gas inlet 241 A may be the same as a diameter of a first intermediate gas outlet (if included). In one embodiment, a first intermediate gas inlet 241 A may have a diameter of 2.29 millimeters. In embodiments, each gas travel path of a plurality of gas travel paths from a bottom gas inlet 203 to each respective gas channel of the first intermediate ring layer 211 is equal in length, such that when a process gas is flowed into bottom gas inlet 203, each flow path from the first intermediate ring layer 211 has an equal gas flow rate and gas flow velocity.

[0042] FIG. 2D is a top-down cross-sectional view of a second intermediate ring layer 211, which may comprise a plurality of gas channels. In embodiments, each gas channel of the plurality of gas channels of the intermediate ring layer 212 may comprise an intermediate gas inlet 242A-D and / or a pair of ends 252A-H. In embodiments, the second intermediate ring layer 212 may comprise four gas channels, each of which may comprise an intermediate gas inlet at its respective midpoint. A second intermediate gas inlet 242A may be located at a midpoint of a third gas channel 232A and connect to an intermediate gas inlet of a next gas ring layer at an endpoint of the second gas channel 231 A. In some embodiments, a second intermediate gas inlet 242A may have a diameter between 0.5-5 millimeters, and the diameter of the second intermediate gas inlet 242A may be the same as a diameter of the second intermediate gas outlet 252A (if included). In one embodiment, a second intermediate gas inlet 242Amay have a diameter of 1.52 millimeters. In embodiments, each gas travel path of a plurality of gas travel paths from a bottom gas inlet 203 to each endpoint of each gas channel of the plurality of the gas channels of the second intermediate ring layer 212 is equal in length, such that when a process gas is flowed into bottom gas inlet 203, each flow path of the intermediate ring layer 212 has an equal gas flow rate and gas flow velocity.Attorney Docket No.: 28245.1257 (L1257PCT)

[0043] FIG. 2E is a top-down view of the gas ring 150. In embodiments, a bottom diameter of a fourth intermediate ring layer 214 may be greater than a top diameter of the fourth intermediate ring layer 214, and the fourth intermediate ring layer 214 may be thus visible from a top-down view. A fifth intermediate ring layer and a top ring layer 221 may have diameters equal to the top diameter of the fourth intermediate layer. In embodiments, a fifth intermediate ring layer (obscured and not shown in this figure) and a top ring layer 221 may be vertically stacked, in that respective order, above the fourth intermediate ring layer.

[0044] The top ring layer may comprise a plurality of gas outlets, which may be coupled to a plurality of gas channels of a lower adjacent ring layer. In some embodiments, a gas outlet 222 of the plurality of gas outlets of the top ring layer may have a diameter between 0.5-5 millimeters. In one embodiment, a gas outlet 222 of the plurality of gas outlets of the top ring layer may have a diameter of 1.52 millimeters. In embodiments, the lower adjacent ring layer is a fifth intermediate ring layer. In some embodiments, a number of gas outlets of the top ring layer 221 may be twice a number of gas channels of the lower adjacent ring layer, and the top ring layer 221 may comprise sixty -four gas outlets when the fifth intermediate ring layer is the lower adjacent ring layer and comprises thirty -two gas channels. Each gas outlet of the plurality of gas outlets of the top ring layer may be disposed at an endpoint of a gas channel of a plurality of gas channels of the lower adjacent ring layer. In embodiments, each gas travel path of a plurality of gas travel paths from the gas inlet 203 to each gas outlet of the plurality of gas outlets of the top ring layer is equal in length, such that when a process gas is flowed into gas inlet 203, each gas outlet of the plurality of gas outlets has an equal gas flow rate and gas flow velocity.

[0045] FIG. 2F is a perspective view of gas ring 150, which may comprise a bottom ring layer 201, a plurality of intermediate ring layers 211-215, and a top ring layer 221. In one embodiment, the bottom ring layer 201 may comprise a first gas channel 202 and a bottom gas inlet 203, which may receive a flow of a process gas from a first gas source 111. In one embodiment, the plurality of intermediate ring layers may comprise a first intermediate ring layer 211, a second intermediate ring layer 212, a third intermediate ring layer 213, a fourth intermediate ring layer 214, and a fifth intermediate ring layer 215. The first intermediate ring layer 211 may be disposed above and permanently bonded to the bottom ring layer 201. The other intermediate ring layers may be stacked above first intermediate ring layer 211 and each other, and the plurality of intermediate ring layers 210 may be permanently bonded to each other.Attorney Docket No.: 28245.1257 (L1257PCT)

[0046] In embodiments, gas ring 150 may horizontally encircle a substrate support (e.g., an electrostatic chuck). Additionally, the gas ring 150 may horizontally encircle an insulator ring 145 within gas delivery system 101. In embodiments, a substrate support 146, which may be an electrostatic puck, may be installed above the insulator ring in the empty space horizontally encircled by the gas ring 150. In one embodiment, the substrate support 146 may be encircled by the gas ring 150 and is configured to support a substrate 152 that is to receive delivery of gas from the top ring layer of the gas ring 150 during processing.

[0047] FIG. 2G depicts an exploded view of a gas ring 150, in accordance with some embodiments. In the exploded view, multiple ring layers 201, 211, 212, 213, 214, 215, 221 are shown disconnected from one another. The gas ring 150 of FIG. 2F is shown, with each of the gas channels, gas inlets, and gas outlets visible.

[0048] FIG. 2H is a perspective view of a recursive gas path network within a gas ring. In embodiments, a recursive gas path network of the gas ring may comprise a first gas channel 202 of a bottom ring layer 201 connected to a gas line 170, The recursive gas path network may additionally include a plurality of gas channels of each of the plurality of intermediate ring layers 210, and a plurality of delivery holes of a process kit ring 142. In some embodiments, gas line 170 may comprise stainless steel and may not be exposed to a plasma during a processing step in process chamber 100. Gas line 170 may be coupled to a first gas channel 202 of gas ring 150 by a gas nozzle 171, which may also comprise stainless steel and may not be exposed to a plasma during a processing step in process chamber 100.

[0049] The first gas channel 202 may be connected to two gas channels of a first intermediate ring layer 211. In embodiments, an endpoint of the first gas channel 202 is connected to a midpoint of a second gas channel 231 of the first intermediate ring layer 211, such that two endpoints of second gas channel 231 are equidistant from a connection between the first gas channel 202 and the second gas channel 231 of the first intermediate ring layer 211. In embodiments, the first gas channel 202 may be wider, taller and / or have a greater diameter than gas channels of the plurality of intermediate ring layers 210, and a gas velocity in the first gas channel may be lower than a gas velocity in a gas channel of an intermediate ring layer.

[0050] A second gas channel 231 of the first intermediate ring layer 211 may be connected to two gas channels of the second intermediate ring layer 212, which may comprise four gas channels. In embodiments, an endpoint of the second gas channel 231 of the first intermediate ring layer 211 is connected to a midpoint of a third gas channel 232 of the second intermediate ring layer 212, such that two endpoints of the third gas channel 232 areAttorney Docket No.: 28245.1257 (L1257PCT)equidistant from a connection between the second gas channel 231 of the first intermediate ring layer 211 and the third gas channel 232 of the second intermediate ring layer 212.

[0051] A third gas channel 232 of the second intermediate ring layer 212 may be connected to two gas channels of the third intermediate ring layer 213, which may comprise eight gas channels. In embodiments, an endpoint of the third gas channel 232 of the second intermediate ring layer 212 is connected to a midpoint of a fourth gas channel 233 of the third intermediate ring layer 213, such that two endpoints of the fourth gas channel 233 are equidistant from a connection between the third gas channel 232 of the second intermediate ring layer 212 and the fourth gas channel 233 of the third intermediate ring layer 213.

[0052] A fourth gas channel 233 of the third intermediate ring layer 213 may be connected to two gas channels of the fourth intermediate ring layer 214, which may comprise sixteen gas channels. In embodiments, an endpoint of the fourth gas channel 233 of the third intermediate ring layer 213 is connected to a midpoint of a fifth gas channel 234 of the fourth intermediate ring layer 214, such that two endpoints of the fifth gas channel 234 are equidistant from a connection between the fourth gas channel 233 of the third intermediate ring layer 213 and the fifth gas channel 234 of the fourth intermediate ring layer 214.

[0053] A fifth gas channel 234 of the fourth intermediate ring layer 214 may be connected to two gas channels of the fifth intermediate ring layer 215, which may comprise thirty -two gas channels. In embodiments, an endpoint of the fifth gas channel 234 of the fourth intermediate ring layer 214 is connected to a midpoint of a sixth gas channel 235 of the fifth intermediate ring layer 215, such that two endpoints of the sixth gas channel 235 are equidistant from a connection between the fifth gas channel 234 of the fourth intermediate ring layer 214 and the sixth gas channel 235 of the fifth intermediate ring layer 215.

[0054] A sixth gas channel 235 of the fifth intermediate ring layer 215 may be connected to a gas outlet 222 of a plurality of gas outlets of the top ring layer 221. In one embodiment, the plurality of gas outlets comprises sixty-four gas outlets, and each sixth gas channel 235 of the fifth intermediate ring layer 215 may be connected to two gas outlets. The two gas outlets connected to the sixth gas channel 235 may be connected at the endpoints of sixth gas channel 235, such that each gas outlet of the two gas outlets is equidistant from a connection between the fifth gas channel 234 of the fourth intermediate ring layer 214 and a sixth gas channel 235 of the fifth intermediate ring layer 215.

[0055] A gas outlet 222 of the plurality of gas outlets of the top ring layer may be connected to a process kit ring, which may be disposed vertically above the gas ring. The process kit ring may comprise a plurality of gas delivery holes, through which a process gas may beAttorney Docket No.: 28245.1257 (L1257PCT)delivered to the edge of a substrate. In embodiments, a process kit ring may comprise a number of delivery holes that is twice a number of gas outlets of the top ring layer 221. In one embodiment, the gas ring comprises five intermediate ring layers, the top ring layer comprises sixty -four gas outlets, and the process kit ring comprise one hundred and twentyeight gas delivery holes. In other embodiments, the gas ring includes greater or fewer intermediate ring layers, and the process kit ring comprises greater or fewer gas delivery holes. In embodiments, a process kit ring may be configured such that a distance from a delivery hole to the nearest gas outlet of the top ring layer is equal for every delivery hole of the process kit ring. A gas travel path from a bottom gas inlet to a delivery hole of the process kit ring may be equal in length for each gas delivery hole of the process kit ring. This may cause a gas flow rate and a gas flow velocity at each gas delivery hole of the process kit ring to be equal when a process gas is flowed into the gas ring. Accordingly, a gas flow distribution near an edge of a wafer disposed in gas delivery system may be uniform.

[0056] In embodiments, a diameter of a delivery hole of process kit ring may be adjustable during design of the process kit ring, and the diameter may be adjusted to control a gas flow velocity at an edge of a wafer. In one embodiment, a diameter of a delivery hole of a process kit ring may be adjusted by removing a first process kit ring from the gas delivery system and replacing it with a second process kit ring. The first process kit ring may have a first plurality of delivery holes in a first diameter. The second process kit ring may have a second plurality of delivery holes in a second diameter, which may be greater or lesser than the first diameter. By changing the process kit ring, the diameters of the process holes may be adjusted, which may adjust a gas velocity at an edge of a wafer. For example, if the second diameter is lesser than the first diameter, the gas velocity at the edge of a substrate may be increased, as gas velocity may be inversely proportional to a gas flow area. Conversely, if the second diameter is greater than the first diameter, a gas velocity at an edge of a substrate may be reduced

[0057] FIG. 3 is a flow chart of an example method 300 for delivering a process gas to an edge of a wafer using a gas ring, in accordance with some embodiments. At block 302, a process gas may be flowed into a gas line gas delivery system by a first gas source. At block 304, a process gas may be flowed through the gas line and a nozzle into an inlet of a gas ring. In block 306, the process gas may be flowed through the gas ring to an edge of a substrate through a plurality of delivery holes of a process kit ring, which may be disposed above a gas ring. In embodiments, every possible gas flow path of a plurality of gas flow paths from the bottom gas inlet to each delivery hole is equal in length, and a gas flow distribution near the edge of the wafer may be uniform.Attorney Docket No.: 28245.1257 (L1257PCT)

[0058] FIG. 4 is a flow chart of an example method 400 for fabricating a gas ring, in accordance with some embodiments. At block 410 of method 400, a plurality of ring layers (e.g., a bottom ring layer, one or more intermediate ring layers, and a top ring layer) of a gas ring are fabricated. In embodiments, one or more ring layers may be fabricated by any method known in the prior art to be suitable for fabricating ceramic or quartz components, which may include etching, pressing, machining, casting, and / or additive manufacturing. In some embodiments, a ring layer may comprise a plurality of parts that may be processed separately and bonded together into one ring layer. In some embodiments, one or more ring layers are fabricated via three-dimensional printing.

[0059] In one embodiment, at block 411, a bottom ring layer of a gas ring is fabricated, the bottom ring layer comprising a first gas channel and a bottom gas inlet. In embodiments, the bottom ring layer of the gas ring may comprise a first gas channel and a bottom gas inlet and may be configured to receive a process gas from the bottom gas inlet. At block 412, a plurality of intermediate ring layers is fabricated, each intermediate ring layer comprising a plurality of gas channels. At block 413, a top ring layer comprising a plurality of gas outlets is fabricated. In embodiments, the top ring layer may comprise a plurality of gas outlets and be configured to output a process gas at the plurality of gas outlets to provide a uniform gas flow distribution near an edge of a substrate. In some embodiments, at least one of the bottom ring layer, the plurality of the intermediate ring layers, and the top ring layer of a gas ring may be fabricated by an additive manufacturing process. In some embodiments, all of the ring layers are manufactured together as different layers of a 3D printed gas ring. In such an embodiment, a separate bonding process may not be performed. In some embodiments, block 410 may comprise separately fabricating the bottom ring layer, the top ring layer, and the plurality of the intermediate ring layers.

[0060] In one embodiment, at block 420 the ring layers of the gas ring are bonded together to form a single gas ring. In one embodiment, at block 421, a bottom ring layer of a gas ring is bonded to a first adjacent intermediate ring layer of a plurality of intermediate ring layers of the gas ring by a fusing process. In embodiments, the first adjacent intermediate ring layer may be an intermediate ring layer with a least number of gas channels of the plurality of intermediate ring layers. At block 422, a plurality of intermediate ring layers, stacked above the bottom ring layer, are bonded to each other by the fusing process. In embodiments, each intermediate ring layer of the plurality of intermediate ring layers may comprise a number of gas channels that is twice a number of gas channels of an adjacent lower layer, and each gas channel of the adjacent lower ring layer may be coupled to two gas channels of theAttorney Docket No.: 28245.1257 (L1257PCT)intermediate ring layer. At block 423, a top ring layer is disposed above the plurality of intermediate ring layers and is bonded to a second adjacent intermediate ring layers of the plurality of intermediate ring layers. In embodiments, the second adjacent intermediate ring layer may be an intermediate ring layer with a greatest number of gas channels of the plurality of intermediate ring layers.

[0061] In one embodiment, a series of fabrication processes in block 410 is performed first, and a series of bonding processes in block 420 are performed second, as depicted in the figure. The series of bonding processes in block 420 may comprise any process known in the prior art to be suitable for bonding quartz or ceramic components together, which may include sintering, application of an adhesive, brazing, and / or cold welding. In some embodiments, a bonding process of the series of bonding processes 420 may comprise a fusing process, which may comprise heating adjacent ring layers and applying pressure to press the adjacent ring layers together. In some embodiments, the various ring layers are bonded at a same time. For example, the bottom ring layer may be bonded to an adjacent intermediate ring layer, the plurality of intermediate ring layers may be bonded to each other, and the top ring layer may be bonded to an adjacent intermediate ring layer all at a same time as part of a single bonding process.

[0062] In some embodiments, processes depicted in block 410 and block 420 are not performed in the order depicted. For example, a bottom ring layer and a first intermediate ring layer may be fabricated, and the bottom ring layer and the first intermediate ring layer may be bonded to each other before fabricating a second intermediate ring layer or a top ring layer. In some embodiments, the processes in block 410 may be performed simultaneously or concurrently, and the processes in block 420 may be performed simultaneously or concurrently. In one embodiment, a gas ring may be fabricated by an additive manufacturing process, wherein a fabrication process and a bonding process are performed simultaneously. The additive manufacturing process may be any process known in the prior art to be suitable for additive manufacturing of ceramic or quartz components, which may include lithographybased ceramic manufacturing, ceramic slurry printing, or fused deposition modeling.

[0063] The preceding description sets forth numerous specific details such as examples of specific systems, components, methods, and so forth, in order to provide a good understanding of several embodiments of the present invention. It will be apparent to one skilled in the art, however, that at least some embodiments of the present invention may be practiced without these specific details. In other instances, well-known components or methods not described in detail or are presented in simple block diagram format in order toAttorney Docket No.: 28245.1257 (L1257PCT)avoid unnecessarily obscuring the present invention. Thus, the specific details set forth are merely explanatory. Particular implementations may vary from these exemplary details and still be contemplated to be within the scope of the present invention

[0064] Although the processes of the methods herein are shown and described in a particular order, the order of the processes of each method may be altered so that certain processes may be performed in an inverse order or so that certain processes may be performed, at least in part, concurrently with other processes. In another embodiment, instructions or sub-processes of distinct processes may be in an intermittent and / or alternating manner.

[0065] It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understand the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

Attorney Docket No.: 28245.1257 (L1257PCT)CLAIMSWe claim:

1. A gas ring comprising:a botom ring layer comprising a first gas channel and a botom gas inlet;a plurality of intermediate ring layers stacked above the bottom ring layer and bonded to the bottom ring layer and to each other, wherein each intermediate ring layer of the plurality of intermediate ring layers comprises a number of gas channels that is twice a number of gas channels of an adjacent lower ring layer, and wherein each gas channel of the adjacent lower ring layer is coupled to two gas channels of the intermediate ring layer; and a top ring layer disposed above the plurality of intermediate ring layers and bonded to an adjacent intermediate ring layer of the plurality of intermediate ring layers, the top ring layer comprising a plurality of gas outlets.

2. The gas ring of claim 1, wherein the first gas channel has a width between 30 and 60 mils.

3. The gas ring of claim 1, wherein the gas ring is configured to provide an even gas distribution about a circumference of a substrate encircled by the gas ring.

4. The gas ring of claim 3, wherein the top ring layer comprises a number of gas outlets that is twice a number of gas channels of the adjacent intermediate ring layer.

5. The gas ring of claim 3, wherein the gas ring comprises at least 5 intermediate ring layers and the top ring layer comprises at least 64 gas outlets.

6. The gas ring of claim 1, wherein the first gas channel has a length approximately equal to half of a circumference of the bottom ring layer.

7. The gas ring of claim 1, wherein a total length of the gas channels of each intermediate ring layer is approximately half of a circumference of the intermediate ring layer.

8. The gas ring of claim 1, wherein the gas ring comprises a ceramic material.Attorney Docket No.: 28245.1257 (L1257PCT)9. The gas ring of claim 8, wherein the ceramic material comprises aluminum oxide or aluminum nitride.

10. The gas ring of claim 1, wherein the gas ring comprises quartz.

11. A system comprising:a gas ring comprising:a bottom ring layer comprising a first gas channel and a bottom gas inlet; a plurality of intermediate ring layers stacked above the bottom ring layer and bonded to the bottom ring layer and to each other, wherein each intermediate ring layer of the plurality of intermediate ring layers comprises a number of gas channels that is twice a number of gas channels of an adjacent lower ring layer, and wherein each gas channel of the adjacent lower ring layer is coupled to two gas channels of the intermediate ring layer; anda top ring layer disposed above the plurality of intermediate ring layers and bonded to an adjacent intermediate ring layer of the plurality of intermediate ring layers, the top ring layer comprising a plurality of gas outlets;a cathode sleeve horizontally enclosing the gas ring;a process kit ring disposed above the gas ring, the process kit ring comprising a plurality of gas delivery holes; anda gas line connected to the bottom gas inlet of the gas ring.

12. The system of claim 11, wherein the gas line is disposed in a channel within a cathode chassis.

13. The system of claim 11, wherein the gas ring comprises a ceramic material.

14. The system of claim 13, further comprising:a substrate support coupled to the gas ring, wherein the substrate support is encircled by the gas ring and is configured to support a substrate that is to receive delivery of gas from the top ring layer of the gas ring during processing.

15. The system of claim 11, wherein the process kit ring comprises a number of gas delivery holes that is twice a number of gas outlets of the top ring layer.Attorney Docket No.: 28245.1257 (L1257PCT)16. The system of claim 11, wherein the process kit ring comprises at least 128 gas delivery holes.

17. A method comprising:bonding a bottom ring layer of a gas ring to a first adjacent intermediate ring layer of a plurality of intermediate ring layers of the gas ring by a fusing process, the bottom ring layer comprising a first gas channel and a bottom gas inlet;bonding the plurality of intermediate ring layers, stacked above the bottom ring layer, to each other by the fusing process, wherein each intermediate ring layer of the plurality of intermediate ring layers comprises a number of gas channels that is twice a number of gas channels of an adjacent lower ring layer, and wherein each gas channel of the adjacent lower ring layer is coupled to two gas channels of the intermediate ring layer; andbonding a top ring layer of the gas ring, disposed above the plurality of intermediate ring layers, to a second adjacent intermediate ring layer of the plurality of intermediate ring layers, the top ring layer comprising a plurality of gas outlets;wherein the bottom ring layer is configured to receive a process gas at the bottom gas inlet, and the top ring layer is configured to output the process gas at the plurality of gas outlets to provide a uniform gas flow distribution near an edge of a substrate.

18. The method of claim 17, further comprising:separately fabricating the bottom ring layer, the top ring layer, and the plurality of intermediate ring layers of the gas ring.

19. The method of claim 17, wherein performing the fusing process comprises:heating adjacent ring layers; andapplying pressure to press the adjacent ring layers together.

20. The method of claim 17, wherein the bonding of the bottom ring layer to the first adjacent intermediate ring layer, the bonding of the plurality of intermediate ring layers to each other, and the bonding of the top ring layer to the second adjacent intermediate ring layer are performed concurrently.

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