skip to main content

Title: Plasticity mechanism for copper extrusion in through-silicon vias for three-dimensional interconnects

In this paper, we demonstrated the plasticity mechanism for copper (Cu) extrusion in through-silicon via structures under thermal cycling. The local plasticity was directly observed by synchrotron x-ray micro-diffraction near the top of the via with the amount increasing with the peak temperature. The Cu extrusion was confirmed by Atomic Force Microscopy (AFM) measurements and found to be consistent with the observed Cu plasticity behavior. A simple analytical model elucidated the role of plasticity during thermal cycling, and finite element analyses were carried out to confirm the plasticity mechanism as well as the effect of the via/Si interface. The model predictions were able to account for the via extrusions observed in two types of experiments, with one representing a nearly free sliding interface and the other a strongly bonded interface. Interestingly, the AFM extrusion profiles seemed to contour with the local grain structures near the top of the via, suggesting that the grain structure not only affects the yield strength of the Cu and thus its plasticity but could also be important in controlling the pop-up behavior and the statistics for a large ensemble of vias.
Authors:
; ; ;  [1] ; ;  [2] ; ;  [3] ; ;  [4]
  1. Microelectronics Research Center and Texas Materials Institute, University of Texas, Austin, Texas 78712 (United States)
  2. Department of Aerospace Engineering and Engineering Mechanics, University of Texas, Austin, Texas 78712 (United States)
  3. Advanced Light Source (ALS), Lawrence Berkeley National Laboratory (LBNL), Berkeley, California 94720 (United States)
  4. SK Hynix, Inc., Icheon-si, Gyeonggi-do (Korea, Republic of)
Publication Date:
OSTI Identifier:
22253995
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 103; Journal Issue: 21; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ATOMIC FORCE MICROSCOPY; COPPER; DIFFRACTION; EXTRUSION; FINITE ELEMENT METHOD; INTERFACES; PLASTICITY; SILICON; X RADIATION