Helps indeed , thx Doug, knew the Nortel (2.5 years in field is not much
[yet]) & Pan.story , didn't the Castin one .
What does "Entek PWB pad coating" stands for ? ; organic on copper ?
Paul Klasek
ResMed
-----Original Message-----
From: Romm, Doug [mailto:[log in to unmask]]
Sent: Saturday, 19 February 2000 3:11
To: [log in to unmask]
Subject: Re: [LF] Components
Paul,
TI data on compatibility with the various lead-free pastes is limited to
date. I have described our history on this issue with water-soluble and
no-clean Sn/Pb pastes. I have also described what I have seen from other
sources that have evaluated Ni/Pd finish components with lead-free pastes.
If you want any specifics on the TI data I am glad to provide it.
Here are my comments:
1. In the past, TI has conducted evaluations on Sn/Pb water soluble and
no-clean type pastes from various vendors. This evaluation can be seen at:
http://www.ti.com/sc/docs/products/logic/package/palladm/index.htm
<http://www.ti.com/sc/docs/products/logic/package/palladm/index.htm>
The paper I refer to is titled "Evaluation of Water Soluble and No-Clean
Solder Pastes with Palladium Plated and Solder Plated SMT Devices" (I've
since learned to shorten the titles of my papers!).
The results of this study did indicate variability in visual wetting
(contact angle) for Ni/Pd finish depending on the solder paste used. This
difference was shown to be visual only, not impacting strength of the solder
joint, as seen in the study. Fortunately, most of the major solder paste
vendors' represented in our study have shown good wetting. Even the few
that showed worse wetting performance have improved their flux chemistry
over time and we have seen improvement.
2. The 1 study performed by TI to evaluate performance with a lead-free
solder paste is located on the same web page above and is titled "Pb-Free
Solder Joint Evaluation". This evaluation looked at AIM Castin paste in
conjunction with TI Ni/Pd components. This study showed good wetting angle
with Ni/Pd and the Castin paste. See the cross-section photos included in
the paper. Also, we saw positive lead pull and temp cycle results.
3. I saw the following papers (with brief summary included below) at the
Minnesota conference:
Title: Lead-Free - The Nortel Experience
Author: Ken Snowden, Nortel
Highlights: In his introductory information Ken commented that the
contribution amounts for the lead in a typical joint are
70% from the solder paste, 25% from the PWB pad, and 5% from the component
lead. Ken also showed pull strength data after
temp cycle using Entek PWB coating, Ni/Pd component finish, and 2 different
lead-free alloy solders. The data showed 14.4N
pull strength for Sn/Pb finish solder, 18.1N for Sn/Cu solder, and 18.0N for
Sn/Ag solder. This is excellent data on good
pull strength performance for Ni/Pd finished components. Nortel has built a
lead-free telephone Sn/Cu paste, Entek PWB pad
coating, various lead-free component finishes (mainly Ni/Pd and pure Sn).
These phones saw 2.5 years in the field with no
problems. Ken's presentation was very positive for Ni/Pd. Mr. Snowden is the
leader of the HDPUG lead-free group in which
TI is participating.
Title: The Panasonic Mini Disk Player: Turning a New Leaf in a Lead-Free
Market
Author: Tom Baggio, Panasonic Factory Automation, Franklin Park, Illinois
Highlights: At the start of the conference Panasonic was presented an award
for introduction of their Mini Disk player as a
lead-free product. Tom presented Panasonic's approach and history in the
lead-free arena. Tom mentioned that several alloy
groups are being investigated for lead-free soldering: Sn/Cu, Sn/Ag,
Sn/Ag/Bi, Sn/Zn, Sn/Bi. Panasonic chose to target
Sn/Cu for wave soldering and Sn/Ag/Bi for surface mount soldering in their
mini disk player. It is commonly known that Bi
reduces the melting point of pure Sn or Sn/Ag alloys allowing minor change
to current reflow profiles but the Bi affects
solder joint strength. Panasonic is focusing on only 3% Bi to allow use of
current reflow profile. Tom showed excellent
lead pull data on Ni/Pd components that they used in build of the mini disk
player. Panasonic has gained worldwide recognition for build of this
lead-free consumer product.
4. TI is participating in several industry consortia (HDPUG, Innolot, EIAJ,
Components FOCUS Group) and additional university group evaluations that
will provide independent evaluations of Ni/Pd finish components with the
primary lead-free solder pastes being considered by the industry.
5. TI is also performing internal evaluations on several of the lead-free
options. We will likely publish our results in the future.
I hope this information gives you an idea on past and current work.
Regards, Doug Romm
Member Group Technical Staff
Texas Instruments
-----Original Message-----
From: Paul Klasek [ mailto:[log in to unmask] <mailto:[log in to unmask]>
]
Sent: Thursday, February 17, 2000 6:11 PM
To: Romm, Doug; [log in to unmask]; [log in to unmask]
Subject: RE: [TN] Tin/Silver Paste and Palladium
Ryan , as far as Palladium recommended fluxing/process , perhaps if you'd
forwarded your original to Doug ;
he'd be likely more than sufficiently across your puzzle .
Doug, as yo gave few good insights on LF ; there is a debate on TN seemingly
on palladium wetting ;
my apologies to drag you across to coals .
I'd be interested in recommended paste myself = to reflow TI finish
optimally ;
i'd presume extensive validations would be done/documented ?
Thanks a lot
Paul Klasek
http://www.resmed.com <http://www.resmed.com>
-----Original Message-----
From: Romm, Doug [ mailto:[log in to unmask] <mailto:[log in to unmask]> ]
Sent: Thursday, 17 February 2000 4:32
To: [log in to unmask]
Subject: Re: [LF] Components
Hans, yes, there are lead-free components (other than passives) available in
the market. This forum is not intended as a marketing source, but I will
mention to you that Texas Instruments supplies Ni/Pd finished components
(lead-free) now. This lead-free finish has been in the market since 1989
and to date over 30 billion Ni/Pd components are in the field. You can see
technical information on this finish at this web site:
http://www.ti.com/sc/docs/products/logic/package/palladm/index.htm
<http://www.ti.com/sc/docs/products/logic/package/palladm/index.htm>
< http://www.ti.com/sc/docs/products/logic/package/palladm/index.htm
<http://www.ti.com/sc/docs/products/logic/package/palladm/index.htm> >
Of course, one of the major issues with lead-free processing and plastic
packages is the dramatic increase in peak reflow temperature with some of
the alloys, with the peak sometimes as high as 260C. TI, along with other
components suppliers, is working with industry consortia to characterize
moisture performance of current package technology at these higher reflow
temperatures.
Best regards, Doug Romm
-----Original Message-----
From: <Hans Juergen Bauer> [ mailto:[log in to unmask]
<mailto:[log in to unmask]>
< mailto:[log in to unmask] <mailto:[log in to unmask]> > ]
Sent: Wednesday, February 16, 2000 10:45 AM
To: [log in to unmask]
Subject: [LF] Components
Dear Colleagues,
is in this circle participating anyone, who takes care of the
components, soldered with leadfree processes??
As I resume a lot of the last messages, nobody is realizing the
suffer of a lot of component commodities. It is clear, that a
board with only some different ceramic components on it, is
solderable leadfree. What about telecoms boards, containing a
lot of different kind of components?
I am curious about the answer,
Hans Juergen
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-----Original Message-----
From: Romm, Doug
Sent: Wednesday, February 16, 2000 11:32 AM
To: 'Leadfree Electronics Assembly E-Mail Forum.'; [log in to unmask]
Subject: RE: [LF] Components
Hans, yes, there are lead-free components (other than passives) available in
the market. This forum is not intended as a marketing source, but I will
mention to you that Texas Instruments supplies Ni/Pd finished components
(lead-free) now. This lead-free finish has been in the market since 1989
and to date over 30 billion Ni/Pd components are in the field. You can see
technical information on this finish at this web site:
http://www.ti.com/sc/docs/products/logic/package/palladm/index.htm
<http://www.ti.com/sc/docs/products/logic/package/palladm/index.htm>
Of course, one of the major issues with lead-free processing and plastic
packages is the dramatic increase in peak reflow temperature with some of
the alloys, with the peak sometimes as high as 260C. TI, along with other
components suppliers, is working with industry consortia to characterize
moisture performance of current package technology at these higher reflow
temperatures.
Best regards, Doug Romm
-----Original Message-----
From: <Hans Juergen Bauer> [ mailto:[log in to unmask]
<mailto:[log in to unmask]> ]
Sent: Wednesday, February 16, 2000 10:45 AM
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