# US 6,720,234 B2 · Semiconductor integrated circuit device and method of manufacturing involving the scale-down width of shallow groove isolation using round processing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,720,234 B2 - Document ID: US6720234B2 - Status: Granted - Kind: B2 - Application number: 10/366,423 - Filed: 2003-02-14 - Published: 2003-08-07 - Granted: 2004-04-13 - Earliest claimed: 1999-03-03 - Assignees: Hitachi, Ltd.; Hitachi ULSI Systems Co., Ltd. - Inventors: Norio Suzuki; Hiroyuki Ichizoe; Masayuki Kojima; Keiji Okamoto; Shinichi Horibe; Kozo Watanabe; Yasuko Yoshida; Shuji Ikeda; Akira Takamatsu; Norio Ishitsuka; Atsushi Ogishima; Maki Shimoda - Web page: https://patentgrep.com/patent/US6720234B2 ## CPC - H10W 10/17: formed using trench refilling with dielectric materials, e.g. shallow trench isolations - H10W 10/014: {using trench refilling with dielectric materials, e.g. shallow trench isolations} - H10W 10/0143: {comprising concurrently refilling multiple trenches having different shapes or dimensions} - H10W 10/0145: {of trenches having shapes other than rectangular or V-shape (H10W10/0143 takes precedence)} - H10B 12/033: {the capacitor extending over the transistor} - H10D 1/042: {using deposition processes to form electrode extensions} - H10D 1/716: {having vertical extensions} - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - H10B: ELECTRONIC MEMORY DEVICES - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract Grooves are defined in a substrate having device isolation regions by dry etching using silicon nitride films and side wall spacers as masks. Thereafter, the side wall spacers lying on side walls of the silicon nitride films are removed and the substrate is subjected to thermal oxidation, whereby the surface of the substrate at a peripheral portion of each active region is subjected to so-called round processing so as to have a sectional shape having a convex rounded shape. ## Claims ### Claim 1 A method of manufacturing a semiconductor integrated circuit device, comprising steps of: (a) providing a semiconductor substrate with a first pattern formed over a first portion of a main surface of said substrate, a second pattern formed over a second portion of said main surface, and a first and a second side wall formed on side surfaces of said first and said second patterns, respectively, wherein a width of said first side wall is greater than a width of said second side wall; (b) forming a first groove, in said substrate, in self-alignment with said first side wall and a second groove, in said substrate, in self-alignment with said second side wall; (c) burying said first and said second grooves with a first insulating film; (d) removing said first and said second patterns; (e) after said step (d), forming a second insulating film over said first portion and said second portion; and (f) after selectively removing said second insulating film formed over said first portion, forming a third insulating film over said second portion such that a thickness of said third insulating film is thinner than a thickness of said second insulating film. ### Claim 2 (depends on 1) A method according to claim 1, wherein said second and said third insulating films are formed by using an oxidation method. ### Claim 3 (depends on 1) A method according to claim 1, wherein each of said second and said third insulating films serves as a gate insulating film of a MISFET. ### Claim 4 (depends on 1) A method according to claim 1, wherein said first portion is an active area for a MISFET included in a logic circuit, and said second portion is an active area for a MISFET included in a memory cell. ### Claim 5 A method of manufacturing a semiconductor integrated circuit device, comprising steps of: (a) providing a semiconductor substrate with a first pattern formed over a first portion of a main surface of said substrate, a second pattern formed over a second portion of said main surface, and a first and a second side wall formed on side surfaces of said first and said second patterns, respectively, wherein a width of said first side wall is greater than a width of said second side wall; (b) forming a first groove, in said substrate, in self-alignment with said first side wall and a second groove, in said substrate, in self-alignment with said second side wall; (c) burying said first and said second grooves with a first insulating film; (d) removing said first and said second patterns; (e) after said step (d), forming a second insulating film over said first portion and said second portion by thermal oxidation; and (f) after selectively removing said second insulating film formed over said first portion, forming a third insulating film over said second portion by thermal oxidation such that a thickness of said third insulating film is thinner than a thickness of said second insulating film. ### Claim 6 (depends on 5) A method according to claim 5, wherein each of said second and said third insulating films serves as a gate insulating film of a MISFET. ### Claim 7 (depends on 6) A method according to claim 6, wherein said first portion is an active area for a MISFET included in a logic circuit, and said second portion is an active area for a MISFET included in a memory cell. ### Claim 8 A method of manufacturing a semiconductor integrated circuit device, comprising steps of: (a) providing a semiconductor substrate with a first pattern formed over a first portion of a main surface of said substrate, and a second pattern formed over a second portion of said main surface; (b) forming a first and a second side wall formed on side surfaces of said first and second patterns, respectively, wherein a width of said first side wall is greater than a width of said second side wall; (c) forming a first groove, in said substrate, in self-alignment with said first side wall and a second groove, in said substrate, in self-alignment with said second side wall; (d) burying said first and second grooves with a first insulating film; (e) removing said first and said second patterns; (f) after said step (e), forming a second insulating film over said first portion and said second portion; and (g) after selectively removing said second insulating film formed over said first portion, forming a third insulating film over said second portion such that a thickness of said third insulating film is thinner than a thickness of said second insulating film. ### Claim 9 (depends on 8) A method according to claim 8, wherein said second and said third insulating films are formed by using an oxidation method. ### Claim 10 (depends on 8) A method according to claim 8, wherein each of said second and said third insulating films serves as a gate insulating film of a MISFET. ### Claim 11 (depends on 8) A method according to claim 8, wherein said first portion is an active area for a MISFET included in a logic circuit, and said second portion is an active area for a MISFET included in a memory cell. ### Claim 12 A method of manufacturing a semiconductor integrated circuit device, comprising steps of: (a) forming a first pattern over a first portion of a main surface of a semiconductor substrate; (b) forming a second pattern over a second portion of said main surface of said substrate; (c) forming a first side wall on a side surface of said first pattern; (d) forming a second side wall on a side surface of said second pattern such that a width of said first side wall is greater than a width of said second side wall; (e) forming a first groove, in said substrate, in self-alignment with said first side wall; (f) forming a second groove, in said substrate, in self-alignment with said second side wall; (g) burying said first and said second groove with an insulating film; and (h) forming a first gate insulating film over said first portion and a second gate insulating film over said second portion such that a thickness of said second gate insulating film is thinner than a thickness of said first gate insulating film. ### Claim 13 (depends on 12) A method according to claim 12, wherein said first and said second gate insulating film are formed by using an oxidation method and each serves as a gate insulating film of a MISFET. ### Claim 14 (depends on 12) A method according to claim 12, wherein said first portion is an active area for a MISFET constituting a logic circuit, and said second portion is an active area for a MISFET constituting a memory cell. ### Claim 15 A method of manufacturing a semiconductor integrated circuit device including a first MISFET formed on a first portion of a main surface of a semiconductor substrate and a second MISFET formed on a second portion of said main surface, wherein a thickness of a first gate insulating film of said first MISFET is greater than a thickness of a second gate insulating film of said second MISFET, comprising steps of: (a) forming a first pattern over said first portion; (b) forming a second pattern over said second portion; (c) forming a first side wall on a side surface of said first pattern; (d) forming a second side wall on a side surface of said second pattern such that a width of said first side wall is greater than a width of said second side wall; (e) forming a first groove, in said substrate, in self-alignment with said first side wall; (f) forming a second groove, in said substrate, in self-alignment with said second side wall; and (g) burying said first and said second groove with an insulating film. ### Claim 16 (depends on 15) A method according to claim 15, wherein said first portion is an active area for a MISFET constituting a logic circuit, and wherein said second portion is an active area for a MISFET constituting a memory cell. ### Claim 17 A method of manufacturing a semiconductor integrated circuit device, comprising steps of: (a) forming a pattern over a first portion of a main surface of a semiconductor substrate; (b) introducing an impurity, in self-alignment with said pattern, in a second portion of said substrate uncovered by said pattern; (c) forming a groove, in said substrate, in self-alignment with said pattern; (d) rounding an edge portion of said groove by using a heat treatment; and (e) burying said groove with an insulating film. ### Claim 18 (depends on 17) A method according to claim 17, wherein, in said step (b), said impurity is introduced by ion implantation, diagonally with respect to a main surface of said substrate, in a portion of said substrate under said pattern. ### Claim 19 (depends on 17) A method according to claim 17, wherein in said step (b), said impurity is introduced to damage said edge portion of said groove. ### Claim 20 (depends on 19) A method according to claim 19, wherein the mass of said impurity is greater than the mass of silicon. ### Claim 21 (depends on 19) A method according to claim 19, wherein in said step (d), said edge portion of said groove is rounded by using said heat treatment to cover said damaged edge portion. ### Claim 22 (depends on 17) A method according to claim 17, wherein, in said step (b), said impurity is introduced by ion implantation, diagonally with respect to a main surface of said substrate, in said edge portion of said groove. ### Claim 23 (depends on 18) A method according to claim 18, wherein in said step (b), said impurity is introduced to damage said edge portion of said groove. ### Claim 24 (depends on 23) A method according to claim 23, wherein in said step (d), said edge portion of said groove is rounded by using said heat treatment to cover said damaged edge portion. ### Claim 25 (depends on 22) A method according to claim 22, wherein in said step (b), said impurity is introduced to damage said edge portion of said groove. ### Claim 26 (depends on 25) A method according to claim 25, wherein in said step (d), said edge portion of said groove is rounded by using said heat treatment to cover said damaged edge portion. ### Claim 27 A method of manufacturing a semiconductor integrated circuit device comprising steps of: (a) forming a first pattern over a first portion of a substrate; (b) forming a second pattern over a second portion of said substrate; (c) forming a first side wall on a side surface of said first pattern; (d) forming a second side wall on a side surface of said second pattern such that a width of said first side wall is greater than a width of said second side wall; (e) forming a first groove, in said substrate, in self-alignment with said first side wall; (f) forming a second groove, in said substrate, in self-alignment with said second side wall; and (g) burying said first and said second groove with an insulating film. ### Claim 28 (depends on 23) A method according to claim 23, wherein said first portion is an active area for a MISFET constituting a logic circuit, and wherein said second portion is an active area for a MISFET constituting a memory cell.