Zhen Zhang, Zhigang Suo Division of Engineering and Applied Sciences - PowerPoint PPT Presentation

1 / 12
About This Presentation
Title:

Zhen Zhang, Zhigang Suo Division of Engineering and Applied Sciences

Description:

Cracking in Interconnects due to Thermal Ratcheting Zhen Zhang, Zhigang Suo Division of Engineering and Applied Sciences Harvard University Jean H. Pr vost – PowerPoint PPT presentation

Number of Views:132
Avg rating:3.0/5.0
Slides: 13
Provided by: Zhe80
Learn more at: http://imechanica.org
Category:

less

Transcript and Presenter's Notes

Title: Zhen Zhang, Zhigang Suo Division of Engineering and Applied Sciences


1
Cracking in Interconnectsdue to Thermal
Ratcheting
  • Zhen Zhang, Zhigang SuoDivision of Engineering
    and Applied Sciences
  • Harvard University
  • Jean H. Prévost
  • Department Civil and Environmental Engineering
  • Princeton University

MRSEC
2
What is the origin of high stress?
3
Ratcheting Plastic Deformation
Huang, Suo, Ma, Fujimoto, J. Mater. Res., 15,
1239 (2000)
4
Ratcheting Plastic Deformation
membrane stress due to CTE mismatch
Metal yields every cycle !
What is the crack behavior?
5
2D Shear Lag Model
Gradual loss of constraint Stress relaxes in
crack wake, but intensifies at crack tip.
  • Two challenges for simulation
  • Crack growth
  • Plasticity

X-FEM
Linear creep analogy
6
Extended Finite Element Method (X-FEM)
  • Nodal Enrichment functions
  • Displacement jumps
  • Singular crack tip field

Time-saving
Moës, Dolbow, Belytschko, Int. J. Num Math. Eng,
46, 131 (1999).
7
Linear Ratcheting-Creep Analogy
Time-saving
Huang, Suo, Ma, Acta Materialia, 49, 3039-3049
(2001)
8
Semi-infinite Stationary Crack in Blanket Film
  • Both creep and ratcheting calculation show the
    same trend.
  • Comparison of time cost
  • Creep 1hr 20min
  • Ratchet 22 hr

9
Finite Stationary Crack in Blanket Film
10
Crack Propagation in a Blanket Film
Initiation
Steady-state
11
Simulation of Cracks Propagation in Interconnects
Tensile stress
Compressive region
12
Summary
Ratcheting deformation in metal layer
High temperature packaging
Cracking in interconnects
High stress in SiN passivation film
Thermal cyclic loading
X-FEM Linear creep analogy
Simulation of cracking in interconnects becomes
feasible
Write a Comment
User Comments (0)
About PowerShow.com