There are no standards/guidelines at this time, although the IPC has
recently convened a task group to put one together along the lines of
the IPC7095 for BGAs. 

 

Bob Willis and I have advocated a maximum of 20% voiding (whether by a
single void or multiple voids) in either the central or edge
terminations when viewed by x-ray inspection. However, some people may
define a higher total percentage voiding as acceptable (say 30%,
especially within the central termination) but with the extra proviso
that no single void should exceed perhaps 5 or 10%. This appears to be
more of concern for devices that require the ability to dissipate a
larger quantity of heat and the presence of any large voids may affect
this efficiency.

 

At the end of the day, however, without the any formal limit defined in
IPC610D, or other documents, then I would suggest that you should
negotiate an acceptable limit between yourself and your customer.

 

David

 

Dr. David Bernard 

Product Manager X-ray Systems 

Dage Precision Industries 

Rabans Lane 

Aylesbury 

Buckinghamshire 

HP19 8RG 

United Kingdom 

Tel: +44 1296 317800

Mob:+44 7796 993391 

E-mail: [log in to unmask] 

www.dage-group.com 

 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Tan Geok Ang
Sent: 29 August 2008 02:32
Subject: LGA/QFN voids %

 

Hi All,

             Need you expertise in advising the maxi. allowable void %
in

LGA and QFN. Does any standard state this requirement?

                        Thank and have a nice day!

 

Regards

GA Tan

 

---------------------------------------------------

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 has been scanned by the MessageLabs Email Security System.
For more information please visit http://www.messagelabs.com/email 
______________________________________________________________________

---------------------------------------------------
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
-----------------------------------------------------