Dewey
We have all been down the road before. As George correctly points out the mechanism for an immersion process is an ionic exchange (which is also the mechanism for corrosion). Once the surface of the host material is no longer exposed to the plating solution it passivates and the process reaches completion. It is difficult to conceive of this being more than a few micro inches thick and certainly not approaching or suppressing 10 micro inches.
Obviously more is involved than an immersion process. There are overtones here of an electroless process which is normally caused by a catalyst being present. My guess is that both of these processes are occurring simultaneously, however the suppliers are not commenting on this apparent contradiction. Trying to classify these coatings will be difficult until the suppliers explain to some extent what is taking place. What we now have are "immersion and augmented immersion" processes. We may want to classify both types under a single inclusive title such as the one above until the industry is provided some additional information.
Best regards
Lee
J. L. Parker Ph.D.
JLP Consultants LLC
(804) 779 3389
----- Original Message -----
From: Whittaker, Dewey (AZ75)<mailto:[log in to unmask]>
To: [log in to unmask]<mailto:[log in to unmask]>
Sent: Friday, May 27, 2005 1:04 PM
Subject: Re: [TN] Immersion Silver - Fab notes
As the Lead-Free initiatives take place Immersion Silver is one of the
leading candidates. The word Immersion to me means that the final thickness
is self-limiting by nature. If this is not the case or the term is not
definitive enough, this must be resolved, because we have more at stake than
just a tarnished image.
Dewey
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wenger, George M.
Sent: Friday, May 27, 2005 9:52 AM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Re: [TN] Immersion Silver - Fab notes
Rudy,
If you assume that all immersion silver chemistries in use are replacement
chemistries than you should expect the silver thickness to be self-limiting.
However, during our implementation of immersion silver we tested "immersion
silver" palted boards that had 45u" thick silver as measured by XRF and also
confirmed by Auger depth profiling and cross sectioning. My background
isn't chemistry but it appears that some of the immersion silver chemistries
must have an some auto-catalytic action as well as replacement.
Regards,
George
George M. Wenger
Reliability / FMA Engineer
Base Station and Subsystems Group
Andrew Corporation, 40 Technology Drive, Warren, NJ 07059 (908) 546-4531
[log in to unmask]<mailto:[log in to unmask]>
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of R Sedlak
Sent: Friday, May 27, 2005 12:37 PM
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Re: [TN] Immersion Silver - Fab notes
Dave: I have never heard of anyone being able to get over about 12
microinches of Silver, I think the 25 microinch number came from somebody
trying to build a spec they could meet no matter what.
Remember, Silver is an immersion finish, which means it is self-limiting,
when all the Copper is covered, plating ceases, no matter what you do..
Rudy Sedlak
RD Chemical Company
Dave Seymour <[log in to unmask]<mailto:[log in to unmask]>> wrote:
Gerard,
This is a prelimary run of boards for us. I am just trying to get my ducks
in a run before going and having the same conversation with our board
supplier.
The first set of numbers came out of table 3-1 in the draft.
Based on your comments, I'll start the conversation in the 8-12 micro inch
range.
Thanks
dave
Gerard O'Brien wrote:
>Dave - there is only one supplier of the thin Silver and they are now
>offering a thicker silver. Given that, the majority is thick silver.
>25 micro inches on what pad size? Did they follow the 30% rule for
>collimator to pad for XRF measurement? Were they using the correct
>energy level to measure I Ag?
>The 4553 group is actively working to determine the upper limit due to
>the fears of Ag3Sn IMC's that are known bad actors when it comes to
>solder joint embrittlement. I would suggest having an independent check
>on their thickness.
>
>Regards
>
>Gerard O'Brien
>Co-chairman 4-14 plating
>
>-----Original Message-----
>From: Dave Seymour [mailto:[log in to unmask]]
>Sent: Friday, May 27, 2005 9:03 AM
>To: [log in to unmask]<mailto:[log in to unmask]>
>Subject: Re: [TN] Immersion Silver - Fab notes
>
>All,
>
>The IPC draft IPC-4553 spec listed below mentions two types of valid
>silver plating.
>Thin 3-5 micro inch and Thick as 8-12 micro inch.
>
>What are board fabricators typically using Thin or Thick?
>
>Also, I saw a presentation from a board shop recently with Silver
>thickness up to 25 micro inch.
>
>It that too thick?
>
>What is too Thick?
>
>Thanks in advance,
>Dave Seymour
>
>
>Gerard O'Brien wrote:
>
>
>
>>There is a new spec that has just completed balloting - IPC-4553. Ken,
>>you can go the committee home page 4-14 at ipc.org and find a copy of
>>the
>>
>>
>draft
>
>
>>that will soon be released.
>>
>>Regards
>>
>>
>>Gerard O'Brien
>>Co-chairman 4-14
>>
>>-----Original Message-----
>>From: Ken Patel [mailto:[log in to unmask]]
>>Sent: Wednesday, March 09, 2005 1:51 PM
>>To: [log in to unmask]<mailto:[log in to unmask]>
>>Subject: [TN] Immersion Silver - Fab notes
>>
>>All,
>>What kind of note should I put on fab drawing if I want to use
>>Immersion Silver as my surface finish. Is there any IPC- document that
>>also I can refer to as part of my note.
>>
>>Any help will be appreciated.
>>
>>re,
>>ken patel
>>
>>
>>
>>
>>__________________________________
>>Celebrate Yahoo!'s 10th Birthday!
>>Yahoo! Netrospective: 100 Moments of the Web
>>http://birthday.yahoo.com/netrospective/
>>
>>---------------------------------------------------
>>Technet Mail List provided as a service by IPC using LISTSERV 1.8e To
>>unsubscribe, send a message to [log in to unmask]<mailto:[log in to unmask]> with following text in
>>the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt
>>or (re-start) delivery of Technet send e-mail to
>>[log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing
>>per day of all the posts: send e-mail to
>>[log in to unmask]: SET Technet Digest
>>Search the archives of previous posts at:
>>http://listserv.ipc.org/archives Please visit IPC web site
>>http://www.ipc.org/contentpage.asp?Pageid=4.3.16
>>for additional information, or contact Keach Sasamori at
>>[log in to unmask] or 847-615-7100 ext.2815
>>-----------------------------------------------------
>>
>>---------------------------------------------------
>>Technet Mail List provided as a service by IPC using LISTSERV 1.8e To
>>unsubscribe, send a message to [log in to unmask]<mailto:[log in to unmask]> with following text in
>>the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt
>>or (re-start) delivery of Technet send e-mail to
>>
>>
>[log in to unmask]: SET Technet NOMAIL or (MAIL)
>
>
>>To receive ONE mailing per day of all the posts: send e-mail to
>>
>>
>[log in to unmask]: SET Technet Digest
>
>
>>Search the archives of previous posts at:
>>http://listserv.ipc.org/archives Please visit IPC web site
>>http://www.ipc.org/contentpage.asp?Pageid=4.3.16
>>
>>
>for additional information, or contact Keach Sasamori at [log in to unmask]<mailto:[log in to unmask]>
>or 847-615-7100 ext.2815
>
>
>>-----------------------------------------------------
>>
>>
>>
>>
>>
>>
>
>--
>Dave Seymour, CID+
>Catapult Communications Inc.
>800 Perimeter Park Dr, Suite A
>Morrisville, NC 27560
>
>Direct: (919)653-4249
>Main: (919)653-4180
>Fax: (919)653-4297
>
>[log in to unmask]
>
>---------------------------------------------------
>Technet Mail List provided as a service by IPC using LISTSERV 1.8e To
>unsubscribe, send a message to [log in to unmask]<mailto:[log in to unmask]> with following text in
>the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt
>or (re-start) delivery of Technet send e-mail to
>[log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing
>per day of all the posts: send e-mail to
>[log in to unmask]: SET Technet Digest
>Search the archives of previous posts at:
>http://listserv.ipc.org/archives Please visit IPC web site
>http://www.ipc.org/contentpage.asp?Pageid=4.3.16
>for additional information, or contact Keach Sasamori at [log in to unmask]<mailto:[log in to unmask]>
>or 847-615-7100 ext.2815
>-----------------------------------------------------
>
>---------------------------------------------------
>Technet Mail List provided as a service by IPC using LISTSERV 1.8e To
>unsubscribe, send a message to [log in to unmask]<mailto:[log in to unmask]> with following text in
>the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt
>or (re-start) delivery of Technet send e-mail to [log in to unmask]<mailto:[log in to unmask]>: SET
>Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the
>posts: send e-mail to [log in to unmask]<mailto:[log in to unmask]>: SET Technet Digest Search the
>archives of previous posts at: http://listserv.ipc.org/archives<http://listserv.ipc.org/archives> Please
>visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/contentpage.asp?Pageid=4.3.16> for
>additional information, or contact Keach Sasamori at [log in to unmask]<mailto:[log in to unmask]> or
>847-615-7100 ext.2815
>-----------------------------------------------------
>
>
>
>
--
Dave Seymour, CID+
Catapult Communications Inc.
800 Perimeter Park Dr, Suite A
Morrisville, NC 27560
Direct: (919)653-4249
Main: (919)653-4180
Fax: (919)653-4297
[log in to unmask]<mailto:[log in to unmask]>
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e To
unsubscribe, send a message to [log in to unmask]<mailto:[log in to unmask]> with following text in the
BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or
(re-start) delivery of Technet send e-mail to [log in to unmask]<mailto:[log in to unmask]>: SET Technet
NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send
e-mail to [log in to unmask]<mailto:[log in to unmask]>: SET Technet Digest Search the archives of
previous posts at: http://listserv.ipc.org/archives<http://listserv.ipc.org/archives> Please visit IPC web
site http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/contentpage.asp?Pageid=4.3.16> for additional
information, or contact Keach Sasamori at [log in to unmask]<mailto:[log in to unmask]> or 847-615-7100
ext.2815
-----------------------------------------------------
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e To
unsubscribe, send a message to [log in to unmask]<mailto:[log in to unmask]> with following text in the
BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or
(re-start) delivery of Technet send e-mail to [log in to unmask]<mailto:[log in to unmask]>: SET Technet
NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send
e-mail to [log in to unmask]<mailto:[log in to unmask]>: SET Technet Digest Search the archives of
previous posts at: http://listserv.ipc.org/archives<http://listserv.ipc.org/archives> Please visit IPC web
site http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/contentpage.asp?Pageid=4.3.16> for additional
information, or contact Keach Sasamori at [log in to unmask]<mailto:[log in to unmask]> or 847-615-7100
ext.2815
-----------------------------------------------------
http://mail.yahoo.com<http://mail.yahoo.com/>
----------------------------------------------------------------------------
--------------------
This message is for the designated recipient only and may contain
privileged, proprietary, or otherwise private information.
If you have received it in error, please notify the sender immediately and
delete the original. Any unauthorized use of this email is prohibited.
----------------------------------------------------------------------------
--------------------
[mf2]
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e To
unsubscribe, send a message to [log in to unmask]<mailto:[log in to unmask]> with following text in the
BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or
(re-start) delivery of Technet send e-mail to [log in to unmask]<mailto:[log in to unmask]>: SET Technet
NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send
e-mail to [log in to unmask]<mailto:[log in to unmask]>: SET Technet Digest Search the archives of
previous posts at: http://listserv.ipc.org/archives<http://listserv.ipc.org/archives> Please visit IPC web
site http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/contentpage.asp?Pageid=4.3.16> for additional
information, or contact Keach Sasamori at [log in to unmask]<mailto:[log in to unmask]> or 847-615-7100
ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask]<mailto:[log in to unmask]> with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]<mailto:[log in to unmask]>: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]<mailto:[log in to unmask]>: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives<http://listserv.ipc.org/archives>
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16<http://www.ipc.org/contentpage.asp?Pageid=4.3.16> for additional information, or contact Keach Sasamori at [log in to unmask]<mailto:[log in to unmask]> or 847-615-7100 ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
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 or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
