Title :
Misalignment-Free Air-Gap (MFAG) Interconnect with Via Base Structure for 45/65nm Node and Below
Author :
Noguchi, Junji ; Oshima, Takayuki ; Matsumoto, Takashi ; Uno, Shoichi ; Sato, Kiyohiko ; Konishi, Nobuhiro ; Saito, Tatsuyuki ; Miyauchi, Masanori ; Hotta, Syoji ; Aoki, Hideo ; Kikuchi, Toshiyuki ; Watanabe, Kunihiko ; Kikushima, Ken-ichi
Author_Institution :
Micro Device Div., Hitachi Ltd., Tokyo
Abstract :
A misalignment-free air-gap (MFAG) interconnect with via base was proposed to overcome a via misalignment issue. A conventional via structure is fabricated at limited areas around via sites, whereas the other wires have air-gaps. The good yield in 800k vias´ chains was confirmed. The reliability of SIV, EM and TDDB were studied. There was no via degradation after thermal stress of 200degC/500hrs. The EM lifetime of an air-gap interconnect corresponds to that of a conventional damascene interconnect. Also an air-gap interconnect has longer TDDB lifetime by a factor of 1 to 2 than conventional damascene. A wire capacitance can be controlled by etched-back thickness, and capacitance reduction by about 17 to 32% was confirmed. The frequency of the ring oscillator in the air-gap interconnect was higher by 17% on average than that in a conventional damascene interconnect
Keywords :
air gaps; integrated circuit interconnections; integrated circuit reliability; 45 nm; 65 nm; EM lifetime; MFAG interconnect; SIV reliability; TDDB lifetime; capacitance reduction; damascene interconnect; etched-back thickness; misalignment-free air-gap interconnect; ring oscillator; thermal stress; via base structure; via misalignment; wire capacitance; Air gaps; Capacitance; Etching; Frequency; Lithography; Resists; Ring oscillators; Thermal degradation; Thermal stresses; Wire;
Conference_Titel :
Interconnect Technology Conference, 2006 International
Conference_Location :
Burlingame, CA
Print_ISBN :
1-4244-0104-6
DOI :
10.1109/IITC.2006.1648678
