The effect of dynamic-local deformation on transistor characteristics by operation heating in 3D-IC

2014 Fiscal Year Final Research Report

• Project/Area Number: 25820133
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Electron device/Electronic equipment
• Research Institution: Tohoku University
• Principal Investigator: KINO Hisashi 東北大学, 学際科学フロンティア研究所, 助教 (10633406)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 3D IC / 金属マイクロバンプ / アンダーフィル / 信頼性 / 曲げ応力

Outline of Final Research Achievements

A three-dimensional (3-D) IC has many lots of through-Si vias (TSVs) and metal microbumps to achieve electrical connections between stacked thinned LSI chips, and also has organic adhesives to obtain completely bonded thinned IC chips. However, these elements, especially microbumps and organic adhesives, induce static and dynamic local bending of the thinned IC chips. In this study, for the first time, we investigated impacts of the static and dynamic local bending on MOSFET characteristics using a novel test structure.
We demonstrated that the static local bending changed the carrier mobility accordingly with the position between the Si microbump and MOSFET using a novel test structure. We also demonstrated that the dynamic local bending changed the MOSFET performance. These results show that it is necessary to carefully design the layout of microbumps and MOSFETs in order to realize higher performance 3-D IC with suppressing circuit performance fluctuation due to local bending stress.

Free Research Field

半導体工学