Thereis some data available. The vast majority of data is still by far on the SAC305default lead-free alloy since alloy accounts for 99% of users and has been inuse for over 10 years now.
Thereare a few users of SnCu based solder pastes right now although cost reductionpressures are pushing for these alternatives having low or no silver.Onecharacteristic that is noted by experience is a lesser wetting using SnCu basedsolders, so there are process changes required if you are to maintain solderjoint reliability.
Ido not believe it is a drop in and some stencil design and reflow profilechanges are required for its implementation to be truly successful.Some high reliability customers also engage on extensive tests toconfirm joint metallurgy is within their expectations.
Senior Market Development Engineer
Mr. Biocca was a chemist with many years experience in soldering technologies. He presented around the world in matters relating to process optimization and assembly. He was the author of many technical papers delivered globally. Mr. Biocca was a respected mentor in the electronics industry. He passed away in November, 2014.
Both DfR Solutions and iNEMI have published data onSN100C performance. For the most part, it falls in between SAC305 and SnPb.
Dr. Craig D. Hillman
CEO & Managing Partner
Dr. Hillman's specialties include best practices in Design for Reliability, strategies for transitioning to Pb-free, supplier qualification, passive component technology and printed board failure mechanisms.