Evaluation of in-plane local stress distribution in stacked IC chip using dynamic random access memory cell array for highly reliable three-dimensional IC

Seiya Tanikawa, Hisashi Kino, Takafumi Fukushima, Mitsumasa Koyanagi, Tetsu Tanaka

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

As three-dimensional (3D) ICs have many advantages, IC performances can be enhanced without scaling down of transistor size. However, 3D IC has mechanical stresses inside Si substrates owing to its 3D stacking structure, which induces negative effects on transistor performances such as carrier mobility changes. One of the mechanical stresses is local bending stress due to organic adhesive shrinkage among stacked IC chips. In this paper, we have proposed an evaluation method for in-plane local stress distribution in the stacked IC chips using retention time modulation of a dynamic random access memory (DRAM) cell array. We fabricated a test structure composed of a DRAM chip bonded on a Si interposer with dummy Cu/Sn microbumps. As a result, we clarified that the DRAM cell array can precisely evaluate the in-plane local stress distribution in the stacked IC chips.

Original languageEnglish
Article number04EC07
JournalJapanese journal of applied physics
Volume55
Issue number4
DOIs
Publication statusPublished - 2016 Apr 1

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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