Copyright © (2004) by MRS. Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distrubuted for profit. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee.
Intermetallic compound (IMC) spalling from electroless Ni-P film was investigated with lead-free solders (Sn-3.5 wt.% Ag and pure Sn) in terms of solder deposition methods (electroplating vs solder paste), P content in Ni-P layer (4.6, 9, and 13 wt.% P), and deposited solder thickness (120 and 200µm). The reaction of Ni-P with Sn3.5Ag paste easily led to IMC spalling after 2min reflow at 250°C while IMCs adhered to the Ni-P layer after 10min reflow for the reaction with electroplated Sn or Sn3.5Ag. It has shown that both solder composition and solder deposition method are important in determining IMC spalling from the Ni-P layer. The spalling increased with P content in the Ni-P layer as well as with solder volume. Ni3Sn4 intermetallics formed as a needleshaped morphology in the early stage and changed into a chunky shape. Needle-shaped compounds exhibited a higher propensity for spalling from the Ni-P layer than chunky shaped compounds because molten solder can easily penetrate into the interface between needle shaped IMCs and the P-rich layer.
By: Y. C. Sohn, Jin Yu, S. K. Kang, D. Y. Shih; T. Y. Lee
Published in: Journal of Materials Research, volume 19, (no 8), pages 2428-36 in 2004
LIMITED DISTRIBUTION NOTICE:
This Research Report is available. This report has been submitted for publication outside of IBM and will probably be copyrighted if accepted for publication. It has been issued as a Research Report for early dissemination of its contents. In view of the transfer of copyright to the outside publisher, its distribution outside of IBM prior to publication should be limited to peer communications and specific requests. After outside publication, requests should be filled only by reprints or legally obtained copies of the article (e.g., payment of royalties). I have read and understand this notice and am a member of the scientific community outside or inside of IBM seeking a single copy only.
Questions about this service can be mailed to reports@us.ibm.com .