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Texture of Al films for wafer-level thermocompression bonding

Abstract

Properties of aluminum thin films for thermocompression bonding have been studied in terms of surface roughness, grain size, and grain orientation by AFM, SEM, XRD and EBSD for thermocompression bonding. Al films were sputter deposited directly on Si and thermally oxidized Si wafers, respectively. The resulting Si/Al and Si/SiO2/Al sample types were compared after annealing (300–550 °C) in vacuum. The Si/SiO2/Al film samples showed higher surface roughness than the Si/Al samples. The as-deposited films had (111) preferred orientation, while (100) and (110) oriented Al grains were also present in Si/SiO2/Al samples. The Si/SiO2/Al samples and Si/Al sample annealed at 550 °C had a conical <111> texture. The observed evolution of the grain structure with annealing temperature is discussed in terms of native oxide, surface roughness, diffusivity and grain orientation dependent mechanical properties in order to shine light on previously observed differences in Alsingle bondAl thermocompression wafer-level bonding with Si/SiO2/Al and Si/Al wafers.
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Category

Academic article

Language

English

Author(s)

  • Nishant Malik
  • Vishnukanthan Venkatachalapathy
  • Wilhelm Dall
  • Kari Schjølberg-Henriksen
  • Erik Poppe
  • Maaike M. Visser Taklo
  • Terje Finstad

Affiliation

  • SINTEF Industry / Metal Production and Processing
  • SINTEF Digital / Smart Sensors and Microsystems
  • University of Oslo

Year

2017

Published in

Superlattices and Microstructures

ISSN

0749-6036

Volume

106

Page(s)

216 - 233

View this publication at Norwegian Research Information Repository