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Ask the Experts

April 30, 2012 - Updated
April 24, 2012 - Originally Posted

BGA Reflow on HASL PCBs

Is it feasible to mount BGAs (23 x 23mm size, 256 balls, pitch 1.27 mm) on HASL PCBs?The process is lead-free.

T.S.Y.

Expert Panel Responses

Yes.Several PC manufacturers are using Lead-Free HASL

Dr. Craig D. Hillman
CEO & Managing Partner, DfR Solutions

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.

Very feasible... youcan specify the land/land flatness you want on the BGA pattern and also,specify the lead-free HASL you wish to have for your Solder Finish. The Assembler willneed to use a "paste additive" process, and understand what SolderFinish you have given them to work with. The stencil should beminimal thickness (.006 - .008) and will actually negate most pad/padvariation. From that point, youneed to ensure your profiling can completely reflow the solder, with doubledrop, and allow a maximum soak dwell time to improve solder joint quality. I would recommendhighest solder powder content possible, +90% for this process and we would usea Type IV powder as well.

Rodney Miller
Capital Equipment Operations Manager, Specialty Coating Systems

Rodney is currently Operations manager at SCS coatings, Global Leader in Parylene and Liquid Coating equipment. Rodney applies his BS in Computer Integrated Manufacturing from Purdue University, along with 20+ years of Electronic manufacturing and Equipment Assembly, to direct the Equipment business at SCS Coatings. "We provide unique, value added coating equipment solutions for our customers". Including conformal, spin and Parylene coating expertise.

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