# US 7,407,835 B2 · Localized slots for stress relieve in copper > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,407,835 B2 - Document ID: US7407835B2 - Status: Granted - Kind: B2 - Application number: 11/357,696 - Filed: 2006-02-17 - Published: 2006-06-29 - Granted: 2008-08-05 - Earliest claimed: 2001-12-14 - Assignees: Taiwan Semiconductor Manufacturing Company, Ltd. - Inventors: Harry Chuang - Web page: https://patentgrep.com/patent/US7407835B2 ## CPC - H10W 20/089: {using processes for implementing desired shapes or dispositions of the openings, e.g. double patterning} - H10W 20/435: {Cross-sectional shapes or dispositions of interconnections} - H10W 20/031: {of conductive parts of the interconnections} - H10W 20/43: Layouts of interconnections - H10W 20/42: Vias, e.g. via plugs - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract In accordance with the objectives of the invention a new method is provided for the creation of interconnect metal. Current industry practice is to uniformly add slots to wide and long copper interconnect lines, this to achieve improved CMP results. These slots, typically having a width in excess of 3 μm and having a length in excess of 3 μm, are added to interconnect lines having a width that is equal to or in excess of 12 μm. This approach however does not, due to its lack of selectivity of location of the slots, solve problems of localized stress that are associated with isolated single vias in the metal lines. For this reason, the invention provides for the addition of one or more localized slots adjacent to isolated vias in bottom or top metal lines that are no wider than about 2 microns. ## Claims ### Claim 1 A method of forming copper interconnects in the fabrication of an integrated circuit device comprising: providing a substrate having a point of electrical contact in or on a surface of said substrate and having a first insulating layer overlying said substrate; forming a first copper interconnect to said electrical contact through an opening in said first insulating layer wherein said first copper interconnect comprises a first single isolated via and an overlying first copper line wherein said first single via is isolated from other vias formed through said first insulating layer and located elsewhere on said substrate; and forming a first slot in said first copper line overlying said first single isolated via wherein said first slot is adjacent to an interface between said first single isolated via and said first copper line and wherein said first slot provides stress relief at said interface. ### Claim 2 (depends on 1) The method according to claim 1 further comprising: forming a second insulating layer overlying said first copper interconnect; and forming a second copper interconnect through said second insulating layer to said first copper interconnect wherein said second copper interconnect comprises a second single isolated via and a second copper line overlying said second single isolated via wherein said second single via is isolated from other vias formed through said second insulating layer elsewhere on said substrate. ### Claim 3 (depends on 1) The method according to claim 1 wherein said first copper line has a width of more than about 0.2 μm. ### Claim 4 (depends on 2) The method according to claim 2 wherein said second copper line has a width of more than about 0.2 μm. ### Claim 5 (depends on 2) The method according to claim 2 wherein said first slot in said first copper line provides stress relief at the interface of said second single isolated via and said second copper line. ### Claim 6 (depends on 2) The method according to claim 2 further comprising forming a second slot in said second copper line overlying said second single isolated via wherein said second slot is adjacent to an interface between said second single isolated via and said second copper line and wherein said second slot in said second copper line provides stress relief at the interface between said second single isolated via and said second copper line. ### Claim 7 (depends on 1) The method according to claim 1 wherein said first slot comprises: a first slot portion spaced a first distance from said first single isolated via in an X-direction; a second slot portion spaced a second distance from said first single isolated via in an X-direction opposite from said X-direction of said first slot portion and having a same first Y-direction placement relative to said first isolated single via as said first slot portion; and a third slot portion spaced a third distance from said first single isolated via in a second Y-direction placement different from said first Y-direction placement wherein said third slot portion contacts a section of said first slot portion and a section of said second slot portion thereby forming a single said first slot. ### Claim 8 (depends on 7) The method according to claim 7 wherein said first, second, and third slot portions have a rectangular or square shape. ### Claim 9 (depends on 7) The method according to claim 7 wherein a section of said first slot portion contacted by said third slot has a length defined by a fourth distance and wherein a section of said second slot portion contacted by said third slot has a length defined by a fifth distance. ### Claim 10 (depends on 7) The method according to claim 7 wherein said first distance is between about 0.1 and 0.4 μm. ### Claim 11 (depends on 7) The method according to claim 7 wherein said second distance is between about 0.1 and 0.4 μm. ### Claim 12 (depends on 7) The method according to claim 7 wherein said third distance is between about 0.05 and 0.3 μm. ### Claim 13 (depends on 9) The method according to claim 9 wherein said fourth distance is between about 0.1 and 0.5 μm. ### Claim 14 (depends on 9) The method according to claim 9 wherein said fifth distance is between about 0.1 and 0.5 μm. ### Claim 15 (depends on 7) The method according to claim 7 wherein said first slot portion has dimensions of between about 0.1 and 0.5 μm by between about 0.5 and 1.0 μm. ### Claim 16 (depends on 7) The method according to claim 7 wherein said second slot portion has dimensions of between about 0.1 and 0.5 μm by between about 0.5 and 1.0 μm. ### Claim 17 (depends on 7) The method according to claim 7 wherein said third slot portion has dimensions of between about 0.1 and 0.5 μm by between about 0.9 and 1.5 μm. ### Claim 18 (depends on 6) The method according to claim 6 wherein said second slot in said second copper line comprises: a first slot portion spaced a first distance from said second single isolated via in an X-direction; a second slot portion spaced a second distance from said second single isolated via in an X-direction opposite from said X-direction of said first slot portion and having a same first Y-direction placement relative to said second single isolated via as said first slot portion; and a third slot portion spaced a third distance from said second single isolated via in a second Y-direction placement different from said first Y-direction placement wherein said third slot portion contacts a section of said first slot portion and a section of said second slot portion thereby forming a single said second slot. ### Claim 19 (depends on 18) The method according to claim 18 wherein said first, second, and third slot portions have a rectangular or square shape. ### Claim 20 (depends on 18) The method according to claim 18 wherein a section of said first slot portion contacted by said third slot has a length defined by a fourth distance and wherein a section of said second slot portion contacted by said third slot has a length defined by a fifth distance. ### Claim 21 (depends on 18) The method according to claim 18 wherein said first distance is between about 0.1 and 0.4 μm, said second distance is between about 0.1 and 0.4 μm, and said third distance is between about 0.05 and 0.3 μm. ### Claim 22 (depends on 20) The method according to claim 20 wherein said fourth distance is between about 0.1 and 0.5 μm and said fifth distance is between about 0.1 and 0.5 μm. ### Claim 23 (depends on 18) The method according to claim 18 wherein said first slot portion has dimensions of between about 0.1 and 0.5 μm by between about 0.5 and 1.0 μm, said second slot portion has dimensions of between about 0.1 and 0.5 μm by between about 0.5 and 1.0 μm, and said third slot portion has dimensions of between about 0.1 and 0.5 μm by between about 0.9 and 1.5 μm. ### Claim 24 A method of forming copper interconnects in the fabrication of an integrated circuit device comprising: providing a first copper line over a substrate; forming an insulating layer overlying said first copper line; forming a copper interconnect to said first copper line through an opening in said insulating layer wherein said copper interconnect comprises a first single isolated via and an overlying second copper line wherein said first single isolated via is isolated from other vias formed through said insulating layer and located elsewhere on said substrate; and forming a slot in at least one of said first copper line underlying said first single isolated via and second copper line overlying said first single isolated via wherein said slot is adjacent to an interface between said first single via and said at least one of said first and second copper lines and wherein said slot provides stress relief at interfaces between said first single isolated via and said first copper line and between said first single isolated via and said second copper line. ### Claim 25 (depends on 24) The method according to claim 24 wherein said slot comprises: a first slot portion spaced a first distance from said first single isolated via in an X-direction; a second slot portion spaced a second distance from said first single isolated via in an X-direction opposite from said X-direction of said first slot portion and having a same first Y-direction placement relative to said first single isolated via as said first slot portion; and a third slot portion spaced a third distance from said first single isolated via in a second Y-direction placement different from said first Y-direction placement wherein said third slot portion contacts a section of said first slot portion and a section of said second slot portion thereby forming a single said slot. ### Claim 26 (depends on 25) The method according to claim 25 wherein said first, second, and third slot portions have a rectangular or square shape. ### Claim 27 (depends on 25) The method according to claim 25 wherein a section of said first slot portion contacted by said third slot has a length defined by a fourth distance and wherein a section of said second slot portion contacted by said third slot has a length defined by a fifth distance. ### Claim 28 (depends on 25) The method according to claim 25 wherein said first distance is between about 0.1 and 0.4 μm, said second distance is between about 0.1 and 0.4 μm, and said third distance is between about 0.5 and 3.0 μm. ### Claim 29 (depends on 26) The method according to claim 26 wherein said fourth distance is between about 0.1 and 0.5 μm and said fifth distance is between about 0.1 and 0.5 μm. ### Claim 30 (depends on 25) The method according to claim 25 wherein said first slot portion has dimensions of between about 0.1 and 0.5 μm by between about 0.5 and 1.0 μm, said second slot portion has dimensions of between about 0.1 and 0.5 μm by between about 0.5 and 11.0 μm, and said third slot portion has dimensions of between about 0.1 and 0.5 μm by between about 0.9 and 1.5 μm. ### Claim 31 (depends on 24) The method according to claim 24 wherein said first and second copper lines have a width of more than about 0.2 μm.