TECHNET Archives

November 2006

TechNet@IPC.ORG
Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
Re: More Separation in BGA joints
From:
Vladimir Igoshev <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Vladimir Igoshev <[log in to unmask]>
Date:
Wed, 15 Nov 2006 19:00:15 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (1 lines) 
Yes, you are right, there is surface tension, BUT flux should facilitate amalgamation (or "initial contact").



As far as the gaps is conserned, I don't think there is a visible film in the picture between the ball and pads. When a proper cross-section is prepared, then the molding compaund penetrates underneath the package and fills in airgaps. That is whay I think is visible in the picture.



Regards,



Vladimir



-----Original Message-----

From: TechNet

To: [log in to unmask]

Sent: Wed Nov 15 16:15:34 2006

Subject: Re: [TN] More Separation in BGA joints



They were in contact. It is just that being in contact alone does not

guarantee agglomeration. The surface tension between the two droplets of

molten solder (melted solder paste on the pad, and melted solder ball)

must still be overcome. For whatever reason, this is not happening.

Probably because of the temperature differential of the two liquids, or

the film between them, which is clearly defined in the pictures, or

both. My approach would be to increase the temperature slightly and

perhaps for a slightly longer TALT to facilitate full agglomeration. 245

is not hot enough.



-----Original Message-----

From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier

Sent: Wednesday, November 15, 2006 2:37 PM

To: [log in to unmask]

Subject: Re: [TN] More Separation in BGA joints



Hi Vladimir,

But how else would the balls deform?







Werner



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

Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 1.8e

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

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

ATOM RSS1 RSS2