I believe that one of the other reason for switching to HASL from gold
immersion is the 'Black Pad syndrome' that the industries is unable to solve
at this point in time. If I am mistaken, please correct me.
Francis
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Craig Hillman
Sent: Thursday, November 16, 2000 2:59 PM
To: [log in to unmask]
Subject: Re: [TN] Is HASL board a better choice compare to immersion gold?
Actually, studies by Lucent have highlighted some quality issues with
immersion gold. "Random" infant mortality due to brittle fracture has been
seen, at a failure rate between 50 to 1000 ppm. Root-causes have been
speculated, but not conclusively determined.
Craig
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Mark Simmons
Sent: Thursday, November 16, 2000 12:01 PM
To: [log in to unmask]
Subject: Re: [TN] Is HASL board a better choice compare to immersion
gold?
Jacob, all responsible engineering involves trade offs. the trick is
not throwing out the baby with the bath water, eh? If things are working
well with the immersion AU, why switch? While it's true that "nothing
solders like solder", your motives to switch should require more than a
claim. Your particular design may or may not lend itself to the HASL
process. If it does, the cost savings could be significant. But, be
prepared for some flexability in the quality area, as the acceptability
criteria will be less cut and dried than AU. We have seen specs from
"coverage" to one mil. depending on design and process compatability. Don't
forget that the "real" issue is Solderability. One size does not fit all and
your mileage may vary.
Mark Simmons, V-Score Central
"" wrote:
Technetter,
Recently, we're asked to change our boards finishing from immersion
gold to HASL due to to some claims that HASL finishing is better in sense of
joint adhesion for the BGA & QFP component. How true is that?
To my knowledge, HASL boards is troublesome too as it has surface
coplanarity issue.
Is it right to say that the coplanarity of the solder is measured
using the solder thickness measurement from 250 microinch to 750 microinch.
Regards,
JACOB PAO KING HING
Supplier Quality Engineer,
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