# US 2014/0151888 A1 · Air-Gap Formation in Interconnect Structures > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0151888 A1 - Document ID: US20140151888A1 - Status: Published application - Kind: A1 - Application number: 13/691,499 - Filed: 2012-11-30 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: Taiwan Semiconductor Manufacturing Company, Ltd. - Applicants: Taiwan Semiconductor Manufachring Company, Lt - Inventors: Cheng-Hsiung Tsai; Chung-Ju Lee; Tien-I Bao - Web page: https://patentgrep.com/patent/US20140151888A1 ## CPC - H10W 20/46: comprising air gaps - H10P 50/00: Etching of wafers, substrates or parts of devices - H10W 20/063: {by forming conductive members before forming protective insulating material} - H10W 20/0633: {using subtractive patterning of the conductive members} - H10W 20/072: {of dielectric parts comprising air gaps} - H10W 20/076: {in via holes or trenches} - H10W 20/077: {on sidewalls or on top surfaces of conductors (H10W20/076 takes precedence)} - H10W 20/40: Interconnections external to wafers or substrates, e.g. back-end-of-line [BEOL] metallisations or vias connecting to gate electrodes - H10W 20/425: {Barrier, adhesion or liner layers} - H10W 20/47: comprising two or more dielectric layers having different properties, e.g. different dielectric constants - H10W 20/495: {Capacitive arrangements or effects of, or between wiring layers} - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract A structure includes a substrate, and a first metal line and a second metal line over the substrate, with a space therebetween. A first air gap is on a sidewall of the first metal line and in the space, wherein an edge of the first metal line is exposed to the first air gap. A second air gap is on a sidewall of the second metal line and in the space, wherein an edge of the second metal line is exposed to the second air gap. A dielectric material is disposed in the space and between the first and the second air gaps. ## Claims ### Claim 1 A structure comprising: a substrate; a first metal line and a second metal line over the substrate, with a space therebetween; a first air gap on a sidewall of the first metal line and in the space, wherein an edge of the first metal line is exposed to the first air gap, with the edge of the first metal line being a vertical straight edge, and wherein the first air gap has a tapered profile, with lower widths of an upper portion of the first air gap increasingly greater than upper widths of the upper portion of the first air; a second air gap on a sidewall of the second metal line and in the space, wherein an edge of the second metal line is exposed to the second air gap; and a dielectric material comprising a lower portion in the space and between the first and the second air gaps. ### Claim 2 (depends on 1) The structure of claim 1, wherein the first air gap forms a continuous air gap ring encircling the first metal line. ### Claim 3 (depends on 1) The structure of claim 1, wherein the first metal line comprises: a copper-containing feature; and a dielectric barrier layer comprising an edge portion contacting a sidewall of the copper-containing feature, and a top portion contacting a top surface of the copper-containing feature. ### Claim 4 (depends on 3) The structure of claim 3, wherein the dielectric barrier layer further comprises a bottom portion extending underlying the first and the second air gaps, and wherein the lower portion of the dielectric material is over and in contact with the bottom portion of the dielectric barrier layer. ### Claim 5 (depends on 1) The structure of claim 1, wherein the dielectric material further comprises an upper portion overlying the lower portion and the first and the second metal lines, wherein the lower portion and the upper portion are formed of a same material, and wherein no visible interface is located between the lower portion and the upper portion of the dielectric material. ### Claim 6 (canceled) ### Claim 7 (depends on 1) The structure of claim 1, wherein a lower portion the first air gap comprises a substantially vertical sidewall. ### Claim 8 A structure comprising: a substrate; a first metal line over the substrate, wherein the first metal line comprises: a copper-containing line; and a dielectric barrier layer comprising a top portion over and contacting the first metal line, and an edge portion contacting a sidewall of the first metal line; a first air gap encircling the first metal line, wherein the edge portion of the dielectric barrier layer comprises an edge exposed to the first air gap; and a low-k dielectric region comprising a lower portion, wherein the lower portion comprises a sidewall exposed to the first air gap, and wherein the sidewall of the lower portion of the low-k dielectric region is more curved than the edge of the edge portion of the dielectric barrier layer. ### Claim 9 (depends on 8) The structure of claim 8, wherein the low-k dielectric region further comprises an upper portion continuously connected to the lower portion, with no visible interface between the upper portion and the lower portion, and wherein the upper portion of the low-k dielectric region is overlying the first metal line. ### Claim 10 (depends on 9) The structure of claim 9, wherein the upper portion of the low-k dielectric region comprises a bottom surface contacting the top portion of the dielectric barrier layer. ### Claim 11 (depends on 8) The structure of claim 8, wherein the lower portion of the low-k dielectric region has a tapered profile, with a lower width of the lower portion smaller than an upper width of the lower portion of the low-k dielectric region. ### Claim 12 (depends on 8) The structure of claim 8, wherein a top end of the air gap is level with or lower than a top surface of the top portion of the dielectric barrier layer, and wherein the dielectric barrier layer further comprises a bottom portion underlying and exposed to the first air gap. ### Claim 13 (depends on 12) The structure of claim 12, wherein the bottom portion of the dielectric barrier layer is further underlying and contacting the lower portion of the low-k dielectric region. ### Claim 14 (depends on 8) The structure of claim 8 further comprising: a second metal line over the substrate and level with the first metal line, wherein the dielectric barrier layer further comprises an additional top portion over and contacting the second metal line, and an additional edge portion contacting a sidewall of the second metal line; and a second air gap encircling the second metal line, wherein the additional edge portion of the dielectric barrier layer is exposed to the second air gap, and wherein an additional sidewall of the lower portion of the low-k dielectric region is further exposed to the second air gap. ### Claim at position 15 15-20. (canceled) ### Claim 21 A structure comprising: a substrate; a first low-k dielectric layer over the substrate; a conductive barrier comprising: a first portion over and contacting a top surface of the low-k dielectric layer; and a second portion extending into the low-k dielectric layer, wherein the second portion comprises sidewall portions on sidewalls of the first low-k dielectric layer; a via between the sidewall portions of the conductive barrier; a first metal line over and connected to the via, wherein edges of the first metal line are aligned to edges of the first portion of the conductive barrier; a dielectric barrier layer comprising a top portion over and contacting the first metal line, and edge portions contacting opposite sidewalls of the first metal line; and a first air gap encircling the first metal line, wherein the edge portions of the dielectric barrier layer are exposed to the first air gap. ### Claim 22 (depends on 21) The structure of claim 21 further comprising a second low-k dielectric layer comprising a lower portion, wherein the lower portion comprises a sidewall exposed to the first air gap. ### Claim 23 (depends on 21) The structure of claim 21, wherein the first portion of the conductive barrier comprises a first edge aligned to a second edge of the first metal line, wherein the first edge contacts the dielectric barrier layer. ### Claim 24 (depends on 22) The structure of claim 22, wherein the second low-k dielectric layer further comprises an upper portion, with a bottom surface of the upper portion of the second low-k dielectric layer contacting a top surface of the top portion of the dielectric barrier layer. ### Claim 25 (depends on 22) The structure of claim 22, wherein the lower portion of the second low-k dielectric layer comprises a bottom surface contacting a top surface of the first portion of the dielectric barrier layer. ### Claim 26 (depends on 21) The structure of claim 21, wherein a portion of the metal line extends beyond a respective edge of the via, with the second portion of the conductive barrier on the respective edge of the via, and wherein the portion of the metal line comprises a bottom surface contacting the first portion of the conductive barrier. ### Claim 27 (depends on 1) The structure of claim 1, wherein the lower portion of the dielectric material comprises an edge exposed to the first air gap, wherein the edge of the lower portion of the dielectric material and the edge of the first metal line are opposite edges of the first air gap, and wherein the edge of the lower portion of the dielectric material is more curved than the edge of the first metal line.