# US 7,608,195 B2 · High aspect ratio contacts > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,608,195 B2 - Document ID: US7608195B2 - Status: Granted - Kind: B2 - Application number: 11/358,659 - Filed: 2006-02-21 - Published: 2007-08-23 - Granted: 2009-10-27 - Earliest claimed: 2006-02-21 - Assignees: Micron Technology, Inc. - Inventors: Aaron R. Wilson - Web page: https://patentgrep.com/patent/US7608195B2 ## CPC - H10P 50/283: {by chemical means} - H10P 50/282: {of inorganic materials} - H10P 50/286: {of organic materials} - H10P 50/287: {by chemical means} - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract A process for etching a insulating layer to produce an opening having an aspect ratio of at least 15:1 by supplying a first gaseous etchant having at least fifty (50) percent He to a plasma etch reactor, and exposing the insulating layer to a plasma of the first gaseous etchant. Use of the first gaseous etchant reduces the occurrence of twisting in openings in insulating layers having an aspect ratio of at least 15:1. ## Claims ### Claim 1 A process for etching an insulating layer, comprising: first exposing the insulating layer to a second plasma of a second gaseous etchant comprising Ar, Xe, and combinations thereof to form an opening having an aspect ratio of less than 15:1; and second exposing the insulating layer to a first plasma of a first gaseous etchant having at least fifty percent helium (He) to etch the opening having an aspect ratio of at least 15:1, thereby increasing the aspect ratio to greater than 15:1, wherein the first gaseous etchant has a lower molecular weight than the second gaseous etchant. ### Claim 2 (depends on 1) The process of claim 1, wherein the second gaseous etchant includes He. ### Claim 3 (depends on 2) The process of claim 2, including: exchanging the second gaseous etchant for the first gaseous etchant once the aspect ratio of the etched openings reaches approximately 15:1. ### Claim 4 (depends on 1) The process of claim 1, where the insulating layer is an oxide selected from the group consisting of silicate glass, silicon oxide, a material formed using one or more silanes, and tetraethyl orthosilicate (TEOS). ### Claim 5 (depends on 1) The process of claim 1, where the first gaseous etchant is a mixture of He and Ar. ### Claim 6 (depends on 1) The process of claim 1, where the first gaseous etchant is approximately ninety percent He and approximately ten percent Ar. ### Claim 7 (depends on 1) The process of claim 1, where the first gaseous etchant is approximately one hundred percent He. ### Claim 8 (depends on 1) The process of claim 1, where the opening includes an opening selected from the group consisting of: vias, contacts, and trenches. ### Claim 9 A process for etching an insulating layer, comprising: exposing the insulating layer in a plasma etch reactor to a plasma of a heavy ion gaseous etchant comprising, a first inert gas; and a first reactive gas, to etch an opening to an aspect ratio of less than approximately 15:1; exchanging the heavy ion gaseous etchant for a light ion gaseous etchant comprising, a second inert gas; and a second reactive gas, once the aspect ratio of the etched opening reaches approximately 15:1 to further etch the opening to an aspect ratio of at least 20:1; and wherein the light ion gaseous etchant has a lower mean molecular weight of the mixture of the second inert gas and the second reactive gas than the mean molecular weight of the first inert gas and the first reactive gas in the heavy ion gaseous etchant. ### Claim 10 (depends on 9) The process of claim 9, where the first inert gas is comprised of a heavy ion and the second inert gas is comprised of a light ion, wherein the light ion has a lower molecular weight than the heavy ion. ### Claim 11 (depends on 10) The process of claim 10, where the heavy ion is selected from the group consisting of Ar, Xe, krypton (Kr), bromine (Br), large fluorocarbon ions, and combinations there of, and the light ion is selected from the group consisting of He, neon (Ne), chlorine (Cl), and fluorine (F). ### Claim 12 (depends on 9) The process of claim 9, where the first reactive gas is comprised of a heavy ion and the second reactive gas is comprised of a light ion, wherein the light ion has a lower molecular weight than the heavy ion. ### Claim 13 (depends on 12) The process of claim 12, where the heavy ion is Br and the light ion is Cl. ### Claim 14 A process for etching an insulating layer, comprising: exposing the insulating layer in a plasma etch reactor to a plasma of a heavy ion reactive gas etchant to etch an opening to an aspect ratio of less than approximately 15:1; exchanging the heavy ion reactive gas etchant for a light ion reactive gas etchant once the aspect ratio of the etched opening reaches approximately 15:1 to further etch the opening to an aspect ratio of at least 20:1; and wherein the light ion reactive gas has a lower molecular weight than the heavy ion reactive gas. ### Claim 15 (depends on 14) The process of claim 14, where the heavy ion reactive gas etchant is Br and the light ion reactive gas etchant is Cl. ### Claim 16 A process for etching an insulating layer, comprising: first exposing the insulating layer to a second plasma of a second gaseous etchant comprising Ar, Xe, and combinations thereof to etch an opening up to an aspect ratio of approximately 15:1; and second exposing the insulating layer to a first plasma of a first gaseous etchant having at least fifty percent He to etch the opening having an aspect ratio of at least 15:1, thereby increasing the aspect ratio to greater than 15:1, wherein the first gaseous etchant has a lower molecular weight than the second gaseous etchant. ### Claim 17 (depends on 16) The process of claim 16, where the insulating layer is an oxide selected from the group consisting of silicate glass, silicon oxide, a material formed using one or more silanes, and tetraethyl orthosilicate (TEOS). ### Claim 18 (depends on 16) The process of claim 16, where the first gaseous etchant to etch the opening having an aspect ratio of at least 15:1 is a mixture of He and Ar. ### Claim 19 (depends on 18) The process of claim 18, where the first gaseous etchant is approximately ninety percent He and approximately ten percent Ar. ### Claim 20 (depends on 16) The process of claim 16, where the opening includes an opening selected from the group consisting of: vias, contacts, and trenches. ### Claim 21 A process for etching an insulating layer to produce a high aspect ratio contact (HARC), comprising: etching the insulating layer with a first plasma of a heavy ion etchant to produce the HARC having an aspect ratio of less than 15:1; further etching the insulating layer with a second plasma of a light ion gaseous etchant to enlarge the HARC to an aspect ratio of at least 20:1; wherein the light ion gaseous etchant includes at least fifty percent helium (He), and the light ion gaseous etchant has a lower molecular weight than the heavy ion gaseous etchant. ### Claim 22 (depends on 21) The process of claim 21, where the light ion gaseous etchant is He. ### Claim 23 (depends on 21) The process of claim 21, where the heavy ion gaseous etchant includes He. ### Claim 24 An etching process, comprising: supplying a gaseous etchant to a plasma etch reactor; etching a surface of an insulating layer with a plasma of the gaseous etchant to create an opening; adding at least fifty percent helium (He) to the gaseous etchant once the opening has reached an aspect ratio of at least 15:1; and forming the opening using the gaseous etchant with at least fifty percent helium (He) added to have a bottom and a side in the insulating layer that allows an axis perpendicular to the insulating layer to pass through the opening to the bottom uninterrupted by the side of the opening and having an aspect ratio of at least 20:1. ### Claim 25 (depends on 24) The process of claim 24, where a distance between the axis perpendicular to the insulating layer and the side is less than approximately forty nm. ### Claim 26 (depends on 24) The process of claim 24, where the gaseous etchant with at least fifty percent helium (He) added is effective to increase the production of the opening as compared to otherwise identical etching with the gaseous etchant lacking at least fifty percent He. ### Claim 27 (depends on 24) The process of claim 24, where the gaseous etchant with at least fifty percent helium (He) added is effective to maintain a constant etch rate as the aspect ratio of the opening reaches and exceeds at least 15:1. ### Claim 28 A method for operating an etch reactor, comprising: alternatively supplying a light ion gaseous etchant having at least fifty percent He to the etch reactor, and a heavy ion gaseous etchant comprising Ar, Xe, and combinations thereof, the light ion gaseous etchant having a lower molecular weight than the heavy ion gaseous etchant; supplying an insulating layer; first etching an opening to an aspect ratio of less than 15:1 with a first plasma of the heavy ion gaseous etchant; and second etching with a second plasma of the light ion gaseous etchant the opening having a bottom and a side in the insulating layer that allows an axis perpendicular to the insulating layer to pass through the opening to the bottom uninterrupted by the side of the opening, and having an aspect ratio of at least 15:1, thereby increasing the aspect ratio to greater than 15:1. ### Claim 29 (depends on 28) The method of claim 28, wherein the heavy ion gaseous etchant includes He. ### Claim 30 (depends on 28) The method of claim 28, including: exchanging the heavy ion gaseous etchant with the light ion gaseous etchant once the aspect ratio of the etched opening reaches approximately 15:1.