# US 7,466,534 B2 · High capacitance density vertical natural capacitors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,466,534 B2 - Document ID: US7466534B2 - Status: Granted - Kind: B2 - Application number: 11/422,457 - Filed: 2006-06-06 - Published: 2007-12-06 - Granted: 2008-12-16 - Earliest claimed: 2006-06-06 - Assignees: International Business Machines Corporation - Inventors: Anil K. Chinthakindi - Web page: https://patentgrep.com/patent/US7466534B2 ## CPC - H01G 4/228: Terminals - H01G 4/30: Stacked capacitors (H01G4/33 takes precedence) - H10D 1/692: {Electrodes} - H10W 20/496: {Capacitor integral with wiring layers} - H01G 4/33: Thin- or thick-film capacitors {(thin- or thick-film circuits; capacitors without a potential-jump or surface barrier specially adapted for integrated circuits, details thereof, multistep manufacturing processes therefor)} - Y10T 29/435: Solid dielectric type - H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10) - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Disclosed are embodiments of a capacitor with inter-digitated vertical plates and a method of forming the capacitor such that the effective gap distance between plates is reduced. This gap width reduction significantly increases the capacitance density of the capacitor. Gap width reduction is accomplished during back end of the line processing by masking connecting points with nodes, by etching the dielectric material from between the vertical plates and by etching a sacrificial material from below the vertical plates. Etching of the dielectric material from between the plates forms air gaps and various techniques can be used to cause the plates to collapse in on these air gaps, once the sacrificial material is removed. Any remaining air gaps can be filled by depositing a second dielectric material (e.g., a high k dielectric), which will further increase the capacitance density and will encapsulate the capacitor in order to make the reduced distance between the vertical plates permanent. ## Claims ### Claim 1 A capacitor comprising: a substrate; a first node above said substrate; a second node above said substrate and parallel to said first node; and a plurality of vertical conductive plates that extend between said first node and said second node, wherein said conductive plates are alternately connected to one of said first node and said second node at connecting points, wherein said conductive plates comprise main bodies that are planar and approximately parallel, wherein a first spacing between said connecting points of adjacent conductive plates is greater than a second spacing between said main bodies of said adjacent conductive plates, and wherein said conductive plates comprise opposing sidewalls and wherein said capacitor further comprises a stressed nitride film on said opposing sidewalls, wherein on each of said conductive plates said stressed nitride film is thicker on one of said opposing sidewalls than another of said opposing sidewalls. ### Claim 2 (depends on 1) The capacitor of claim 1, wherein said conductive plates have a width that is less than approximately 200 nm and wherein said width is at least four times greater than said second spacing. ### Claim 3 (depends on 1) The capacitor of claim 1, wherein each of said conductive plates comprises a plurality of metal levels that are separated by a dielectric material and that are electrically connected by vias. ### Claim 4 The capacitor of clam 3, wherein said dielectric material has a dielectric constant that is less than approximately 3.9. ### Claim 5 (depends on 3) The capacitor of claim 3, wherein said dielectric material has a dielectric constant that is less than approximately 2.2. ### Claim 6 (depends on 3) The capacitor of claim 3, further comprising a second dielectric material between and encapsulating said conductive plates. ### Claim 7 (depends on 6) The capacitor of claim 6, wherein said second dielectric material has a second dielectric constant that is greater than 5.0. ### Claim 8 A capacitor comprising: a substrate; a first node above said substrate; a second node above said substrate and parallel to said first node; and a plurality of vertical conductive plates that extend between said first node and said second node, wherein said conductive plates are alternately connected to one of said first node and said second node at connecting points, wherein said conductive plates comprise main bodies that are planar and approximately parallel, wherein a first spacing between said connecting points of adjacent conductive plates is greater than a second spacing between said main bodies of said adjacent conductive plates, and wherein said conductive plates comprise opposing sidewalls and wherein said capacitor further sidewall spacers on said opposing sidewalls, wherein on each of said conductive plates said sidewall spacers are thicker on one of said opposing sidewalls than another of said opposing sidewalls.