# US 12,002,659 B2 · Apparatus for generating etchants for remote plasma processes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,002,659 B2 - Document ID: US12002659B2 - Status: Granted - Kind: B2 - Application number: 17/869,987 - Filed: 2022-07-21 - Published: 2023-12-14 - Granted: 2024-06-04 - Earliest claimed: 2022-06-13 - Assignees: Applied Materials, Inc. - Applicants: Applied Materials, Inc. - Inventors: Tae Seung Cho; David Michael Benjaminson; Kenneth Schatz; Ryan Michael Pakulski; Martin Yue Choy; Pratheep Gunaseelan; Chih-Yung Huang - Web page: https://patentgrep.com/patent/US12002659B2 ## CPC - H01J 37/32596: {Hollow cathodes} - H01J 37/32091: {the radio frequency energy being capacitively coupled to the plasma} - H01J 37/32357: {Generation remote from the workpiece, e.g. down-stream} - H01J 37/3244: {Gas supply means} - H01J 37/32541: {Shape} - H01J 37/32568: {Relative arrangement or disposition of electrodes; moving means} - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract A remote plasma source (RPS) for generating etchants leverages symmetrical hallow cathode cavities to increase etchant rates. The RPS includes an upper electrode with a first hollow cavity configured to induce a hollow cathode effect within the first hollow cavity, a lower electrode with a second hollow cavity configured to induce a hollow cathode effect within the second hollow cavity, wherein the first hollow cavity and the second hollow cavity are symmetrical, a first gap positioned between and electrically separating the upper electrode and the lower electrode, and an annular dielectric cover in direct contact with the lower electrode in the first gap and forms a second gap between an uppermost surface of the annular dielectric cover and a lowermost surface of the upper electrode. The annular dielectric cover fills approximately 50% to approximately 95% of a height of the first gap. ## Claims ### Claim 1 An apparatus for processing a substrate, comprising: a process chamber with a chamber body enclosing a processing volume; a remote plasma source (RPS) having a plasma source with an upper electrode and a lower electrode, wherein the upper electrode and the lower electrode are symmetrical with hollow cavities configured to induce a hollow cathode effect within the hollow cavities, wherein the upper electrode and the lower electrode are electrically separated by a first gap with an annular dielectric cover positioned within the first gap, wherein the annular dielectric cover is in direct contact with the lower electrode and forms a second gap between an uppermost surface of the annular dielectric cover and a lowermost surface of the upper electrode, wherein the annular dielectric cover fills approximately 50% to approximately 95% of a height of the first gap, and wherein the RPS is configured to provide radicals or ions into the processing volume; and a radio frequency (RF) power source configured to provide a symmetrical driving waveform on the upper electrode and the lower electrode to produce an anodic cycle and a cathodic cycle of the RPS, wherein the anodic cycle and the cathodic cycle operate in a hollow cathode effect mode. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the annular dielectric cover is a ceramic material. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the annular dielectric cover has an outermost edge with a first thickness and an innermost edge with a second thickness less than the first thickness. ### Claim 4 (depends on 3) The apparatus of claim 3, wherein the second thickness is approximately 1 millimeter to approximately 2 millimeters and the first thickness is less than approximately 95% of the height of the first gap. ### Claim 5 (depends on 3) The apparatus of claim 3, wherein the first thickness slopes downward into a third thickness equal to the second thickness before reaching the innermost edge. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the annular dielectric cover has an inner diameter greater than an outer edge of an opening of the hollow cavities. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the annular dielectric cover has an inner diameter smaller than an outer edge of an opening of the hollow cavities and wherein an innermost edge of the annular dielectric cover extends, at least partially, into the opening. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein capillary holes are spaced in proximity of the innermost edge of the annular dielectric cover. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein the capillary holes have a diameter of less than two times a thickness of a sheath of plasma to be generated with the RPS. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein the upper electrode and the lower electrode are plated with electroless nickel plating. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein an yttria coating is applied to plasma exposed surfaces of the upper electrode and the lower electrode. ### Claim 12 (depends on 10) The apparatus of claim 10, wherein an yttria coating is applied to plasma exposed surfaces with the first gap and in proximity of openings of the hollow cavities of the upper electrode and the lower electrode. ### Claim 13 An apparatus for processing a substrate, comprising: a remote plasma source (RPS) having a plasma source with an upper electrode and a lower electrode, wherein the upper electrode and the lower electrode are symmetrical with hollow cavities configured to induce a hollow cathode effect within the hollow cavities, wherein the upper electrode and the lower electrode are electrically separated by a first gap with an annular dielectric cover positioned within the first gap, wherein the annular dielectric cover is in direct contact with the lower electrode and forms a second gap between an uppermost surface of the annular dielectric cover and a lowermost surface of the upper electrode, wherein the annular dielectric cover fills approximately 50% to approximately 95% of a height of the first gap, and wherein the RPS is configured to provide radicals or ions; and a radio frequency (RF) power source configured to provide a symmetrical driving waveform on the upper electrode and the lower electrode to produce an anodic cycle and a cathodic cycle of the RPS, wherein the anodic cycle and the cathodic cycle operate in a hollow cathode effect mode. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the annular dielectric cover has an outermost edge with a first thickness and an innermost edge with a second thickness less than the first thickness and wherein the second thickness is approximately 1 millimeter to approximately 2 millimeters and the first thickness is less than approximately 95% of the height of the first gap. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein the first thickness slopes downward into a third thickness equal to the second thickness before reaching the innermost edge. ### Claim 16 (depends on 13) The apparatus of claim 13, wherein the annular dielectric cover has an inner diameter greater than an outer edge of an opening of the hollow cavities or wherein the annular dielectric cover has an inner diameter smaller than an outer edge of an opening of the hollow cavities and wherein an innermost edge of the annular dielectric cover extends, at least partially, into the opening. ### Claim 17 (depends on 16) The apparatus of claim 16, wherein capillary holes are spaced in proximity of the innermost edge of the annular dielectric cover and wherein the capillary holes have a diameter of less than two times a thickness of a sheath of plasma to be generated with the RPS. ### Claim 18 (depends on 13) The apparatus of claim 13, wherein the upper electrode and the lower electrode are plated with electroless nickel plating and wherein an yttria coating is applied to plasma exposed surfaces of the upper electrode and the lower electrode on the electroless nickel plating. ### Claim 19 An apparatus for providing a remote plasma source (RPS) for generating etchants, comprising: an upper electrode with a first hollow cavity configured to induce a hollow cathode effect within the first hollow cavity; a lower electrode with a second hollow cavity configured to induce a hollow cathode effect within the second hollow cavity, wherein the first hollow cavity and the second hollow cavity are symmetrical; a first gap positioned between and electrically separating the upper electrode and the lower electrode; and an annular dielectric cover in direct contact with the lower electrode in the first gap and forms a second gap between an uppermost surface of the annular dielectric cover and a lowermost surface of the upper electrode, wherein the annular dielectric cover fills approximately 50% to approximately 95% of a height of the first gap, wherein the annular dielectric cover has an inner diameter smaller than an outer edge of an opening of the second hollow cavity which extends, at least partially, into the opening while directly in contact with a surface of the second hollow cavity, and wherein capillary holes are spaced in proximity of an innermost edge of the annular dielectric cover and have a diameter of less than two times a thickness of a sheath of plasma to be generated with the RPS. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein the upper electrode and the lower electrode are plated with electroless nickel plating and an yttria coating is applied to plasma exposed surfaces of the upper electrode and the lower electrode over the electroless nickel plating.