I have never used Shenmao.

Actually there is quite a bit missing here...

What is the finish on the Powerpak?  Same question for Infineon?
Are you talking about voiding within the center ground slug or only the
signal pins?
What amount of voiding in percentages are you experiencing?
What stencil patterns were used?
Were all the paste formulations the same composition/mesh/flux content?
Why did you use the same reflow profile for different pastes?  
What is meant by paste quality?

Phil



-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of jonathan noquil
Sent: Tuesday, June 21, 2011 8:26 AM
To: [log in to unmask]
Subject: [TN] Solder paste

Hi All
I have been evaluating solder pastes for QFN packages and these are my
findings and
observations. Everybody are welcome to provide comments.

Vehicle: QFN 5 x 6 8 leads (Powerpak footprint) also evaluated those
from
Infineon footprint

1. Observed that NiPdAu plating finish- voiding is less compared to
matte
Sn? Infineon solders well compared to a matte Sn plating QFN.

2. Of all the paste evaluated--Shenmao, Alpha metals, indium, henkel--->
Shenmao has the biggest voiding. But it works Ok with NiPdAu plated QFNs
compared to Matte Sn plating.

3. Stencil opening is varied. Observed no significant effect.

4. All pastes are lead free. SAC305



Questions:

1. Does anyone had experience of using shenmao paste? How does it
perform in
terms of voiding. Why it doesnt work well on Matte Sn finish?

2. Is the compostion of solder paste (Cu content) affect the soldering
performance ex. voids?

3. It seems the paste quality had the biggest impact on voding, any
comments?

4. Evaluation uses the same PCB pattern and stencil openings for
different
type of paste but Shenmao had the largest voids. Do you have
some experience?

We want to improve the voiding quality, any more suggestions.


Thank you for your kind help

Thanks


______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or
[log in to unmask] 
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
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
For additional information, or contact Keach Sasamori at [log in to unmask]
or 847-615-7100 ext.2815
-----------------------------------------------------

------------------------------------------------------------------------------
This message and any attachments are solely for the use of the addressee and may contain L-3 proprietary information that may also be defined as USG export controlled technical data. If you are not the intended recipient, any disclosure, use or distribution of its content is prohibited. Please notify the sender by reply e-mail and immediately delete this message and any attachments.




______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 16.0
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
For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------