Dave, I don't know if this will work, but it may be worth a trial. We had problems with large voids some years ago. Reason was outgassing from hydrogen imbedded in the nickel plate. I do no know how this happened, but a plating bath chemist ought to have the answer. Don't you have comments on my own bga question? How strong and reliable is the less-than-micron thick P-rich SnNi IMC? Inge -------------------------------------------------- From: "Zilber Gil" <[log in to unmask]> Sent: den 25 February 2010 08:07 To: <[log in to unmask]> Subject: Re: [TN] Suggestions on Making BGA Voids > Hi Dave, > > What was the PCB finish? If it is HASL the voids will be much smaller > then if it ENIG. > You can also use microvia between 1-3 or playing with the laminate > thickness. > > Regards, > > Gil > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman > Sent: Thursday, February 25, 2010 5:43 PM > To: [log in to unmask] > Subject: [TN] Suggestions on Making BGA Voids > > Hi gang! Ok, I have a fairly crazy request for suggestions on how to > make BGA voids. First here is the background - Dr. David Bernard > (Dage), Dave Adams (Rockwell Collins) and I are working on a > collaborative project to investigate the thermal cycle solder joint > integrity of BGA components. We are attempting to produce data which the > IPC JSTD 001 committee can use to revise the 25% maximum void criteria. > Despite public rumor, this current IPC JSTD 001 void requirement is > based on actual IPC Class 3 field equipment results submitted to the > committee several years ago. However, BGAs have changed in both size, > pitch and solderball diameter since the creation of the void criteria > thus the reason for collaborative project. > We have a test vehicle which contains BGAs at 0.5mm, 0.8mm and 1.0mm > pitch with each having a corresponding larger solderball diameter. We > have put uvias in the BGA pads to "create" voiding. Great plan, figured > we had it > made- however, after running the test vehicles thru a standard reflow > process (this effort is focused on tin/lead right now) we find that we > have an average void size in the range of 0-5%! My production process > folks are very proud of that result but it doesn't do our voiding > investigation much good (you can imagine the look I got when I told them > they didn't make enough voids greater than 25%). I know that a number > of the Technet community have tried to accomplish this voiding task with > only mild success (i.e. Bev Christian, Martin Wickham, etc.). > > My Technet request is - do you have any suggestions on how to increase > the solderball void size without causing a biased negative impact on the > solder joint quality? I can obviously make some huge solderball voids > (such as pouring Doug's Diet Mt. Dew on the test vehicles) but the > overall quality of the solder joint would not be representative of the > real world product. > > Thanks in advance > > Dave Hillman > Rockwell Collins > [log in to unmask] > > > ______________________________________________________________________ > 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 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 is processed by the PrivaWall Email Security Server. > > > The information contained in this communication is proprietary to Israel > Aerospace Industries Ltd., ELTA Systems Ltd. > and/or third parties, may contain classified or privileged information, > and is intended only for > the use of the intended addressee thereof. 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Thank you. > > > This message is processed by the PrivaWall Email Security Server. > > > > > ______________________________________________________________________ > 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 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 contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- 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 -----------------------------------------------------