Mike
I might add in AT&T we began using large numbers of bare copper (imidazole
coated) boards and backplanes (with press fit pins) in late 70s. I am
unaware of any reliability issues associated with these boards. I believe we
can now say we have demonstrated compliance with the famous Bell Laboratory
40 year life requirement.
Best regards
Lee
J. Lee Parker, Ph.D.
JLP Consultants LLC
804 779 3389
----- Original Message -----
From: "Barmuta, Michael" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, March 07, 2007 10:53 AM
Subject: Re: [TN] immersion silver and exposed copper in small vias
Hi Lee: Just to substantiate yours, Werners, Waynes and others comments,
exposed copper is not a reliability issue. Agreed that any trapped
chemistries in holes can definably be a problem but that is true even if
the final finish is not copper.
When OSP's were coming on the scene in the late eighties/early nineties
we ran extensive testing with IBM Endicott on exposed copper boards.
Included is the testing protocol was electromigration, humidity cycling
and environmental exposure using MFG (mixed flowing gas).
Based on the type of MFG test that is run, it can be very aggressive.
The MFG test exposes the electronic assembly to controlled
concentrations of corrosive gases in a chamber. This simulates X years
of field service based on the number of hours of chamber time the test
is run. We ran the MFG Type-H test for 420 hours which correlates to 10
years of heavy industrial environments such as pulp/paper mills,
waste/water treatment plants, chemical refineries, etc. Bottom line we
found no performance or reliability differences between the copper and
HASL control assemblies.
We've built literally millions of test and measurement instruments over
the last 15-20 years as exposed copper boards. These are used in every
environment imaginable all over the world. We do not see any issues with
the exposed copper from our field service centers.
Regards
Michael Barmuta
Staff Engineer\
Fluke Corp.
Everett WA
425-446-6076
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Lee parker
Sent: Wednesday, March 07, 2007 6:41 AM
To: [log in to unmask]
Subject: Re: [TN] immersion silver and exposed copper in small vias
Copper does not corrode in the since that iron does. Copper is a near
noble
element that behaves more like aluminum; it forms a passivative layer
that
penetrates only a few microns into the material. Think of aerial copper
wire
(so called open wire) used by the phone companies for many years. Where
I
live, the aerial copper wire that was installed in the early 20s is
still in
place and functions as well as it did 90 years ago.
Best regards
Lee
J. Lee Parker, Ph.D.
JLP Consultants LLC
804 779 3389
----- Original Message -----
From: "Hogg, Blair K." <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, March 06, 2007 4:43 PM
Subject: Re: [TN] immersion silver and exposed copper in small vias
I guess I'll have to replace all that corroded copper pipe in my house
with the plastic kind....
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Tuesday, March 06, 2007 4:24 PM
To: [log in to unmask]
Subject: Re: [TN] immersion silver and exposed copper in small vias
Or the Statue of Liberty...
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ian Hanna
Sent: Tuesday, March 06, 2007 3:26 PM
To: [log in to unmask]
Subject: Re: [TN] immersion silver and exposed copper in small vias
That's why they build church roofs out of it I suppose...
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Kevin Glidden
Sent: Tuesday, March 06, 2007 4:20 PM
To: [log in to unmask]
Subject: Re: [TN] immersion silver and exposed copper in small vias
Is this really true? I have only been at this around 7 yrs, but
everything I was ever taught says exposed Cu is not allowed for risk of
corrosion.
-----Original Message-----
From: Wayne Thayer [mailto:[log in to unmask]]
Sent: Tuesday, March 06, 2007 3:52 PM
To: [log in to unmask]
Subject: Re: [TN] immersion silver and exposed copper in small vias
And what's wrong with exposed copper? You certainly aren't going to try
and solder down there, are you? Copper does not corrode quickly, and if
its going to be in a corrosive environment, you're going to have to
conformal coat anyway!
The silver is put on boards only to extend the solderability lifetime of
the bare copper, not as a protectant to prevent opens due to corrosion.
This is not a reliability issue at all.
Wayne Thayer
>>> [log in to unmask] 3/6/2007 12:10:08 pm >>>
Hi Fran
The amount of mask intruding into the hole will depend on the
application method. Our curtain coat operation can cause the mask (circa
1-2 microns) to penetrate about 1/3rd into the hole from both sides but
it has not affected the silver taking on the remaining surface. Is the
mask too thick at the hole entrance to prevent the plating solution
getting good access?
You may also need to confirm by micro section what your customer thinks
he is seeing. Is the mask covering all the hole surface? Hope this
helps.
Regards
Alistair
Alistair F Murray MICT
Technical Manager
Artetch Circuits Limited
England UK
Direct Dial: 01903-712931
www.artetch.co.uk
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Fran Juliot
Sent: 06 March 2007 15:58
To: [log in to unmask]
Subject: [TN] immersion silver and exposed copper in small vias
Our customer is questioning what they feel is exposed copper in 8 mil
vias holes on silver boards. We feel there is mask residue in the holes
which does not allow silver to take. These are holes that are allowed
to be plugged. Has anyone else ran into this issue with thier customers
and do you have the same look or are your small vias covered with silver
all the way through the via?
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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
-----------------------------------------------------
*******************************************************************
This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
the system manager.
This footnote also confirms that this email message has been swept
for the presence of computer viruses.
www.Hubbell.com - Hubbell Incorporated
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------
This message (including any attachments) contains confidential
and/or proprietary information intended only for the addressee.
Any unauthorized disclosure, copying, distribution or reliance on
the contents of this information is strictly prohibited and may
constitute a violation of law. If you are not the intended
recipient, please notify the sender immediately by responding to
this e-mail, and delete the message from your system. If you
have any questions about this e-mail please notify the sender
immediately.
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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
-----------------------------------------------------
|
