Characterization and corrosion behaviour of 96.5Sn-3.0Ag-0.5Cu solder on Cu substrate at different reflow reactions
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Date
2013
Authors
Liu Mei, Lee
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia.
Abstract
96.5Sn-3.0Ag-0.5Cu (SAC305) thin film solder exhibits different surface
characteristics if compared to conventional bulk solder. In thin film solder, the actual
surface is comprised of intermetallic layers whereas in the case of conventional
solder, the intermetallic layers happened at the interfacial region of solder/base metal.
This in turn, resulted in different surface microstructure and chemical composition.
Moreover, a subtle and unstudied aspect of SAC305 in thin film characteristics was
limited. Thus, the effect of solder reflow conditions at various temperatures and
times were investigated. Structural and elemental characterizations indicated that Sn,
Ag3Sn, and Cli6Sns were present in the as-deposited SAC305 thin film on Cu
substrate. After solder reflow, SAC305 thin film was totally reacted and developed
into Cu6Sns then Cu3Sn. Cu6Sn5 is located almost exclusively in the volume,
whereas Cu3Sn appears as a thin uniform layer structure beneath Cu6Sn5• The Cu3Sn
intermetallic layer consistent~y increases with increased temperature but remains
within the thickness of Cu6Sn5• The corrosion behavior of bare Cu, as-deposited
SAC305/Cu and as-reflowed SAC305/Cu at varying reflow temperatures was
investigated by means of potentiodynamic polarization in a 6 M potassium
hydroxide (KOH) solution. Bare Cu was found to possess the best corrosion
resistance, whereas the as-deposited SAC305/Cu had the lowest corrosion resistance.
Description
Keywords
Characterization and corrosion behaviour , Cu substrate at different reflow reactions