Micross

Abstract Preview

Here is the abstract you requested from the DPC_2009_Wafer technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.

An Investigation of Diffusion Barrier Characteristics of Electroless Co(W,P) Layer to Lead-Free SnBi Solder
Keywords: diffusion barrier, lead-free, electroless Co(W, P)
This study investigated the interfacial reactions between SnBi solder and electroless Co(W,P) layer with various crystallinities by utilizing the liquid-state aging test (250aC for 1 hr) and solid-state aging test (120aC up to 1000 hrs) so as to explore the feasibility of electroless Co(W,P) to UBM for low-temperature, lead-free flip-chip bonding. In the sample containing SnBi/amorphous Co(W,P) subjected to liquid-state aging test, a P-rich layer containing Co, Sn, P elements formed in between solder and electroless Co(W,P) whereas the lath-like CoSn3 intermetallic compound (IMC) spalled into solder. The P-rich layer became thicker when the aging time was increased. For the samples subjected to solid-state aging test, a thick IMC layer formed in between solder and Co(W,P) without spallation and the P-rich layer was similar observed. In the samples containing SnBi/polycrystalline Co(W,P) subjected to liquid- and solid-state aging tests, an about 1 m-thick interfacial layer containing various elements including Co, Sn, P, W and Bi formed in between solder and Co(W,P). The needle-like CoSn3 IMCs interlarded with Bi element formed on Co(W,P) without spallation. In conjunction with the analytical results obtained in the case of SnBi/amorphous Co(W,P), it is concluded that, regardless of its crystallinity, electroless Co(W,P) layer is in fact a sacrificial-type barrier to SnBi solder owing to the formation of P-rich layer.
Hung-Chun Pan, Ph.D Candidate
National Chiao Tung University
Hsinchu, Taiwan 30049,
R.O.C.


CORPORATE PREMIER MEMBERS
  • Amkor
  • ASE
  • Canon
  • EMD Performance Materials
  • Honeywell
  • Indium
  • Kester
  • Kyocera America
  • Master Bond
  • Micro Systems Technologies
  • MRSI
  • NGK NTK
  • Palomar
  • Plexus
  • Promex
  • Qualcomm
  • Quik-Pak
  • Raytheon
  • Specialty Coating Systems