skip to main content

SciTech ConnectSciTech Connect

Title: Design for reliability of BEoL and 3-D TSV structures – A joint effort of FEA and innovative experimental techniques

Copper-TSVs for 3D-IC-integration generate novel challenges for reliability analysis and prediction, e.g. the need to master multiple failure criteria for combined loading including residual stress, interface delamination, cracking and fatigue issues. So, the thermal expansion mismatch between copper and silicon leads to a stress situation in silicon surrounding the TSVs which is influencing the electron mobility and as a result the transient behavior of transistors. Furthermore, pumping and protrusion of copper is a challenge for Back-end of Line (BEoL) layers of advanced CMOS technologies already during manufacturing. These effects depend highly on the temperature dependent elastic-plastic behavior of the TSV-copper and the residual stresses determined by the electro deposition chemistry and annealing conditions. That’s why the authors pushed combined simulative/experimental approaches to extract the Young’s-modulus, initial yield stress and hardening coefficients in copper-TSVs from nanoindentation experiments, as well as the temperature dependent initial yield stress and hardening coefficients from bow measurements due to electroplated thin copper films on silicon under thermal cycling conditions. A FIB trench technique combined with digital image correlation is furthermore used to capture the residual stress state near the surface of TSVs. The extracted properties are discussed and used accordingly to investigate the pumping and protrusionmore » of copper-TSVs during thermal cycling. Moreover, the cracking and delamination risks caused by the elevated temperature variation during BEoL ILD deposition are investigated with the help of fracture mechanics approaches.« less
Authors:
; ; ; ;  [1]
  1. Fraunhofer ENAS, Micro Materials Center, Technologie-Campus 3, D-09126 Chemnitz (Germany)
Publication Date:
OSTI Identifier:
22311260
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1601; Journal Issue: 1; Conference: International conference on stress induced phenomena and reliability in 3D microelectronics, Kyoto (Japan), 28-30 May 2012; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANNEALING; COPPER; CORRELATIONS; ELECTRODEPOSITION; ELECTRON MOBILITY; FATIGUE; FRACTURE MECHANICS; INTERFACES; LAYERS; PLASTICITY; RELIABILITY; RESIDUAL STRESSES; SILICON; TEMPERATURE DEPENDENCE; THERMAL CYCLING; THERMAL EXPANSION