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Al-Al thermocompression bonding for wafer-level MEMS packaging

Abstract

The Al-Al thermocompression bonding is studied on test structures suitable for wafer level packaging of MEMS devices. Si wafers with protruding frame structures have been bonded to planar Si wafers all covered with a 1 μm sputtered Al film. The varied bonding process variables were temperature (400 °C-550 °C), bonding force (18-36 kN) and frame widths (100 μm, 200 μm, rounded or sharp corners). The delamination caused by dicing and pull tests is systematically studied. It is concluded that bonding is incomplete at 400 °C, with a low dicing yield. The quality of the bonding is increased by increasing bonding temperature and force as expected. The fractured surfaces and the bonding strength have been studied in detail. The test structures showed an average strength of 20-50 MPa for bonding at or above 450 °C. The current study indicates that strong Al-Al thermocompression bonds can be achieved at or above 450 °C for a typical MEMS bond frame.

Category

Academic chapter/article/Conference paper

Client

  • Research Council of Norway (RCN) / 210601

Language

English

Author(s)

  • Nishant Malik
  • Kari Schjølberg-Henriksen
  • Erik Poppe
  • Terje Finstad

Affiliation

  • University of Oslo
  • SINTEF Digital / Microsystems and Nanotechnology

Year

2013

Publisher

IEEE conference proceedings

Book

The 17th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS & EUROSENSORS XXVII), 2013 Transducers & Eurosensors XXVII, Barcelona, Spain June 16-20

ISBN

978-1-4673-5982-5

Page(s)

1067 - 1070

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