Tuning Stress in Cu Thin Films by Developing Highly (111)-Oriented Nanotwinned Structure

I-Ju Wang, Ching-Shun Ku, Tu-Ngoc Lam, E-Wen Huang, King-Ning Tu, Chih Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We have examined the effect of different bath temperatures on residual stress of both the random-oriented Cu films and the highly (111)-oriented nanotwinned Cu films by synchrotron radiation x-ray measurements. The bath temperature varied from 15 degrees C to 40 degrees C. The results indicate that the average residual stress in the highly (111)-oriented nanotwinned films is higher than that in the randomly oriented Cu films. However, the stress in the highly (111)-oriented Cu decreases with increasing bath temperature. The average residual stress can be reduced from 253 MPa electroplated at 15 degrees C to 95 MPa under a bath temperature of 35 degrees C. We could successfully tune and measure residual stress of the Cu thin films. The films with low residual stress prevent warpage from occurring on the substrate and lower the processing failure in copper direct bonding and other processes that need alignment.

Original languageEnglish
Pages (from-to)109-115
Number of pages7
JournalJournal of Electronic Materials
Volume49
Issue number1
DOIs
StatePublished - Jan 2020

Keywords

  • Residual stress
  • nanotwinned Cu
  • electroplating
  • synchrotron x-ray diffraction
  • RESIDUAL-STRESS
  • ULTRAHIGH-STRENGTH
  • STRAIN
  • GROWTH

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