April 30, 2012
BGA Reflow on HASL PCBs
Is it feasible to mount BGAs (23 x 23
mm size, 256 balls, pitch 1.27 mm) on HASL PCBs?
The process is lead-free.
T.S.Y.
Very feasible... you
can 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 will
need to use a "paste additive" process, and understand what Solder
Finish you have given them to work with.
The stencil should be
minimal thickness (.006 - .008) and will actually negate most pad/pad
variation.
From that point, you
need to ensure your profiling can completely reflow the solder, with double
drop, and allow a maximum soak dwell time to improve solder joint quality.
I would recommend
highest solder powder content possible, +90% for this process and we would use
a Type IV powder as well.
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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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Yes.
Several PC manufacturers are using Lead-Free HASL
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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.
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