Impacts of 3-D integration processes on device reliabilities in thinned DRAM chip for 3-D DRAM

Kang Wook Lee, Ji Chel Bea, Mariappan Murugesan, Takafumi Fukushima, Tetsu Tanaka, Mitsumasa Koyanagi

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

3 Citations (Scopus)

Abstract

Impacts of 3-D integration processes on device reliabilities in thinned DRAM chip were evaluated. The retention characteristics of memory cells were degraded depending on the decreased chip thickness, especially dramatically degraded below 40-μm thickness in the case with under-fill, meanwhile, the retention characteristics were relatively not so degraded until to 30-μm thickness, but suddenly degraded below 20-μm thickness in the case without under-fill. The retention characteristics of DRAM cell in the thinned DRAM chip which was CMP-treated dramatically degraded after intentional Cu diffusion from the backside surface at 300oC annealing. Meanwhile, the retention characteristics in the thinned DRAM chip which was DP-treated did not degrade regardless of the well structure. The retention characteristics of some memory cell arrays with Cu TSV arrays began to degrade after annealing at 300oC for 30min. As the annealing temperature increase higher than 400oC, Cu atoms more spread out into larger area in the DRAM chip via poor barrier layers.

Original languageEnglish
Title of host publication2015 IEEE International Reliability Physics Symposium, IRPS 2015
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages4C21-4C26
ISBN (Electronic)9781467373623
DOIs
Publication statusPublished - 2015 May 26
EventIEEE International Reliability Physics Symposium, IRPS 2015 - Monterey, United States
Duration: 2015 Apr 192015 Apr 23

Publication series

NameIEEE International Reliability Physics Symposium Proceedings
Volume2015-May
ISSN (Print)1541-7026

Other

OtherIEEE International Reliability Physics Symposium, IRPS 2015
CountryUnited States
CityMonterey
Period15/4/1915/4/23

Keywords

  • 3-D DRAM
  • Capacitance-time (C-t)
  • Cu TSV
  • Cu diffusion
  • charge carrier lifetime
  • retention time

ASJC Scopus subject areas

  • Engineering(all)

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