CLEANING IMPLICATIONS OF LEAD-FREE ASSEMBLY AND PACKAGINGAuthor: Thomas M. Forsythe
Company: Kyzen Corporation
Date Published: 2/25/2005 Conference: Pan Pacific Symposium
Additionally, the absence of lead is not the only material change in these new lead-free products. Solder paste developers have aggressively advanced their craft since the days of CFC-113 and RMA, bring the benefits of modern materials to the customers. These new "exotic" materials have enabled a continuous stream of enhanced performance characteristics to be brought to market in the past few years.
These new materials bring various benefits regarding solder effectiveness, but also are subject to the law of unintended consequences. Namely, they often dramatically change the requirements of defluxing materials used in the cleaning process. This paper will detail these new developments.
After detailing how the world, vies-a-vie cleaning requirements, has changed, next the paper will review the evolution of cleaning technology, starting with the CFC-113 days (when many have last considered cleaning) and continuing to the present. This will include a detailed technical analysis of the three cleaning genres: vapor phase, semi-aqueous and aqueous.
Key words: Vapor phase cleaning, semi-aqueous cleaning, aqueous cleaning, lead-free.
The irony of cleaning in the electronics industry is as clear and elegant as anything Shakespeare created. As it was not always this way, a brief review of how we got here is in order, and may provide insight into how cleaning might yet return.
As we look back over the past 15 or so years, we see that the cleaning electronics industry has gone through two distinct phases, or Acts of evolution with regard to cleaning, and a third one is clearly about to begin:
Act I Scene I Cleaning with CFCs
Act I Scene II Cleaning without CFCs
Act II No Clean Solders, some cleaned some not
Act III Lead-free Solders, cleaning?
This paper will review the broader market aspects of cleaning in each of these periods, with a particular emphasis on the technology developments (or lack thereof) in each period with a thorough technical review of where the industry stands today.
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