High density 3D LSI technology using W/Cu hybrid TSVs

M. Murugesan, H. Kino, A. Hashiguchi, C. Miyazaki, H. Shimamoto, H. Kobayashi, T. Fukushima, T. Tanaka, M. Koyanagi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

25 Citations (Scopus)

Abstract

High density 3D LSI technology using W/Cu hybrid through silicon vias (TSVs) has been proposed. Major reliability issues attributed to W/Cu hybrid TSVs in high density 3D LSIs such as (i) thermo-mechanical stress exerted by W TSVs used for signal lines and Cu TSVs used for power/ground lines in active Si, (ii) external gettering (EG) role played by sub-surface defects in thinned Si substrate, and (iii) effect of local stress induced by μ-bumps on device characteristics are discussed. By annealing at the temperature of ≥300°C, both Cu (via size ≤10μm) and W (via size ≤1μm) square TSVs induce only compressive stress at small TSV spacing which will seriously affect the mobility in active Si area, and thus device characteristics. Large compressive stress not only leads to extrusion and peeling of TSV metal, but also die cracking, and it will adversely impact on the reliability of 3D-LSIs. Then it was proposed to increase the TSV pitch to larger than twice of TSV size to avoid these adverse effects in high density 3D-LSI. Sub-surface defects at dry polished (DP) surface well act as potential EG sites for Cu contamination. Influences of mechanical stress induced by μ-bumps on device characteristics were also evaluated and ultra-small size In-Au μ-bump technology has been developed to minimize the influences of μ-bumps on device characteristics.

Original languageEnglish
Title of host publication2011 International Electron Devices Meeting, IEDM 2011
Pages6.6.1-6.6.4
DOIs
Publication statusPublished - 2011
Event2011 IEEE International Electron Devices Meeting, IEDM 2011 - Washington, DC, United States
Duration: 2011 Dec 52011 Dec 7

Publication series

NameTechnical Digest - International Electron Devices Meeting, IEDM
ISSN (Print)0163-1918

Other

Other2011 IEEE International Electron Devices Meeting, IEDM 2011
Country/TerritoryUnited States
CityWashington, DC
Period11/12/511/12/7

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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