Graham and Douglas,
I'm not sure if I agree with Graham for a few reasons. The need for a
more active flux under the BGA is probably due to improper profiling. Now
I would be the first to admit that getting a thermocouple under a BGA is a
bit of a challenge, but it can be done. With the thermal data from the
coolest solder joint of the BGA and the rest of the board instrumented as
usual, a proper reflow profile can be developed.
I would agree that getting the proper reflow profile for the entire board,
including under the BGA, can be very difficult when using a more sensitive
solder paste. Then again, if it were easy it wouldn't be as much fun. If
you need any help with getting that thermocouple under the BGA, let me
know. I have a few ways that may work for you.
As far as needing nitrogen goes, there should be no need for it with the
proper reflow profile. Of course this is assuming the paste doesn't need
it to start with.
Hope this helps you.
John Guy
ACI / EMPF
714 N. Senate Ave.
Indianapolis, IN 46202-3112
voice: (317) 655-EMPF ext.130
fax: (317) 655-3699
e-mail: [log in to unmask]
-----Original Message-----
From: Graham Naisbitt [SMTP:[log in to unmask]]
Sent: Monday, November 03, 1997 7:04 PM
To: [log in to unmask]
Subject: Re: [TN] Responses Needed Please!!Nitrogen use w/ BGA reflow
Douglas, I may not be the most qualified on this subject but, many
customers
have found OA processing (water soluble fluxes/pastes) more successful due
to
the improved activity under the component. With OA, nitrogen or inert gas
soldering is less critical.
If no-clean is in use, nitrogen becomes much more relevant but the flux
activity is generally insufficient to guarantee good soldering under BGA's.
Clean v No-clean? Is this why you have a shy audience?
Graham Naisbitt
Concoat Ltd Email:
[log in to unmask]
Alasan House, Albany Park Tel: +44 (0)1276 691100
Camberley, Surrey GU15 2PL UK Fax: +44 (0)1276 691227
-----Original Message-----
From: TechNet On Behalf Of Douglas H. Bennett
Sent: Monday, November 03, 1997 4:40 PM
To: [log in to unmask]
Subject: [TN] Responses Needed Please!!Nitrogen use w/ BGA reflow
I sent this message last week and am still waitng on some responses. Can
anyone help please???
Hello All,
I am working with some guys just getting into BGA work. We have some
questions about the need for Nitrogen in the reflow process. Does anyone
have any good examples/data/stories etc about how nitrogen has helped with
a BGA application. In other words we are looking for good reasons to
invest in nitrogen to use on the BGA's.
Thanks in advance....
DHB
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