Fatigue strength of electroplated copper thin films under uni-axial stress

Naokazu Murata, Kinji Tamakawa, Ken Suwki, Hideo Miura

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

Fatigue strength of electroplated copper thin films was measured under uni-axial stress. Two kinds of electroplated fihns were prepared for the fatigue test. One was a commercial film mainly used for interconnections in printed wiring boards. The other fihn was grown on a stainless steel substrate by using acid copper sulfate bath without any additive agent. The micro texture of each fihn was observed by using SEM (Scanning Electro Microscope) and SIM (Scanning Ion Microscope). It was found that the micro texture of each film was quite different with each other. The mechanical properties such as the yield stress, fracture elongation and Young's modulus of each film changed significantly from those of bulk copper depending on their micro structure. The low-cycle fatigue strength also varied drastically with each other, while the high-cycle fatigue strength was almost same. The fracture surfaces were observed by SEM after the fatigue test. It was found that there were two fracture modes under the fatigue test. One was a typical ductile fracture, and another was brittle one even under the fatigue load higher than its yield stress. The crack seemed to propagate through the grains when the ductile fracture occurred. On the other, the crack seemed to propagate along grain boundaries ofcolumnar grains when the brittle fracture occurred. These results clearly indicated that the fatigue strength of electroplated copper thin films varies depending on their micro structure.

Original languageEnglish
Title of host publication2008 10th International Conference on Electronic Materials and Packaging, EMAP 2008
Pages41-44
Number of pages4
DOIs
Publication statusPublished - 2008 Dec 1
Event2008 10th International Conference on Electronic Materials and Packaging, EMAP 2008 - Taipei, Taiwan, Province of China
Duration: 2008 Oct 222008 Oct 24

Publication series

Name2008 10th International Conference on Electronic Materials and Packaging, EMAP 2008

Other

Other2008 10th International Conference on Electronic Materials and Packaging, EMAP 2008
CountryTaiwan, Province of China
CityTaipei
Period08/10/2208/10/24

ASJC Scopus subject areas

  • Hardware and Architecture
  • Electrical and Electronic Engineering
  • Mechanical Engineering

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