Hi Bev! To quote Doug Paul's standard phrase "It depends"! There are quite
a number of reference books I can put my hands on which list what the
tin/nickel intermetallic phase thickness will be depending on the time and
temperature it was either i) formed (initial formation, e.g. at molten
temperatures) or ii) grown (secondary formation, e.g. at temperature
exposure such as baking). I can give you a thickness value for a specific
condition. Is that what you want? Or is your question really focused on how
thick tin/nickel intermetallic phase can be tolerated before the
reliability is impacted?
This should be a fun metallurgical discussion!
Dave Hillman
Rockwell Collins
[log in to unmask]
Bev Christian <[log in to unmask]>@ipc.org> on 10/24/2001 02:39:20 PM
Please respond to "TechNet E-Mail Forum." <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
To: [log in to unmask]
cc:
Subject: [TN] Tin/gold Intermetallic
OK, the last one was fun. Let's see what I can "provoke" this time!
There are standards for gold thickness for ENIG, "rules" for the amount of
gold in tin/lead solder joints (~4% for tensile, ~2% for shear), but I have
not found, looking into the TechNet archives or in J. Hwang's or Rahn's or
Manko's books I don't have the Wassink et al book ;( ), what is the range
of acceptable/expected intermetallic thickness for tin/nickel
intermetallic.
I would appreciate your input - any references and results seen in your own
work. Let the discussion begin.
regards,
Bev Christian
Research in Motion
-----Original Message-----
From: Earl Moon [mailto:[log in to unmask]]
Sent: October 24, 2001 6:21 AM
To: [log in to unmask]
Subject: Re: [TN] Antw: [TN] exposing intermetallic on BGA pads...
Guenter,
I cannot believe how much I am learning every minute about soldering and
all
comprising it. Not at all being negative or contrary, I must have ruined
thousands of solder joints in my long life in this business notwithstanding
all the rework I've done and taught others.
All I've ever been taught, done, and taught others is to remove the solder,
with whatever means that works without damaging pads or board materials,
then print paste, place components, and reflow.
I've never even heard of leaving on solder or removing intermetallics -
especially with a glass brush. I finished my last contract, seemingly
successfully, two months ago. Can the world and all its "wonderful"
soldering technology all of a sudden be passing me by in such a short time?
Jeez, a glass brush. Thanks again Guenter, but I must need more help than
even you, Bob Willis, or all other experts can give.
Earl
----------------------------------------------------------------------------
-----
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 the following message: SET
Technet NOMAIL
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 the following message: SET
Technet NOMAIL
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 the following message: SET Technet NOMAIL
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
---------------------------------------------------------------------------------
|
