TECHNET Archives

February 2002

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
David Douthit <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Fri, 22 Feb 2002 11:40:35 -0700
Content-Type:
text/plain
Parts/Attachments:
text/plain (58 lines)
Phil,

Dealing with the "lowest bidder" will not work on this issue!

David A. Douthit
Manager
LoCan LLC

------------------------------

phil bavaro wrote:

> We have used ENIG as our primary BGA board finish for many many, many
> boards built for cellular communications without issues regarding this problem.
>
> We have a major PWB fabricator telling us that they cannot control what
> appears to be a "black pad" problem and that we should be changing to
> Entek's OSP combined with a selective gold process for our standard finish.
>
> I cannot say that we have never had this problem before but usually it was
> more a case of unrinsed soldermask on a pad rather than corroded nickel
> plating beneath the gold finish.
>
> I did the cross sectioning myself and took some great pictures of the
> contaminated pad surfaces that were yielding when subjected to drop testing.
>
> I am convinced that ENIG is a solid finish but I know that it can be
> susceptible to nickel wetting problems.  I have three questions:
>
> 1)  What kind of frequency are the rest of you finding "black pad" to occur
> on ENIG boards?
> 2)  What finish do you use for high density BGA/CSP double sided boards
> that have surface contact (gold) plating requirements?
> 3)  Are any of you using underfill to hopefully negate the solder joint
> brittleness that the black pad surface inherently creates?
>
> ---------------------------------------------------------------------------------
> Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Technet
> To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL
> To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
> Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
> Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
> ---------------------------------------------------------------------------------

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------

ATOM RSS1 RSS2