8 research outputs found
Wetting behaviour of SAC305 solder on different substrates in high vacuum and inert atmospheres
The wettability between solder and substrate is a
very important issue in reliability of soldering process. The
contact angle h is used to measure the degree of wetting. The
contact angle of lead-free alloy Sn-3 % Ag-0.5 % Cu (wt%)
was measured, as a function of temperature, for three different
commercial surface finish substrates used in printed
circuit boards (PCB): Sn, NiAu and Organic Solderability
Preservative (OSP). The measurements were performed by
the sessile drop method in two different atmospheres: high
vacuum and inert gas. In high vacuum the results showed
that on substrates of NiAu and OSP the solder started
spreading suddenly at 225 C and in Sn substrate the contact
angle decreases slightly with temperature. In inert gas
atmosphere the results showed different behaviours: the
contact angle between molten solder in OSP and NiAu
substrates is sensitive to temperature; and, in Sn substrate,
the contact angle does not change with temperature. The
NiAu and OSP substrates showed a better degree of wettability
than Sn substrate, in inert atmosphere.The authors acknowledge the financial support provided through project SI I&DT Projeto em co-promoção No. 36265/2013 (Projeto HMIEXCEL—2013–2015).info:eu-repo/semantics/publishedVersio