Good Morning or Afternoon,
saw movie about the Amtrak incident on Mobile bridge. Terrible. So many unusual failures were involved to cause that accident. The detective work to reconstruct was impressive, they found the sources. Now, need detective work on micro problem, which can also make grey hair. Ordinary aluminium pads, Silicon chip, Autobonded, 25um Au wire, ball, chips silver epoxied, workpiece +150 Centigrades.
One side of chip have normal bonds, other side get oftenly bad bondings with following symptoms: aluminium metallisation bubbles and ball doesn't fasten, the bond pad get what looks like chipouts, but without classic look. Have checked everything: autobonder program, ceramic capillary, chip epoxy bond line, looked after bond pad contaminations, MCM fixture, ball formation, wire quality and a lot more...without finding the reason. Aluminium looks like it has been boiling, but how on earth could it, the machine just adds U/S power.
Maybe Phil, jk or other microguru can whet the neurons and propose some idea? Will post two photos to Steve's headache gallery, one with normal chip before bonding, the other after bonding.
In advance thanks giving I am (Yoda)
Ingemar Hernefjord
Ericsson Microwave Systems
---------------------------------------------------
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 847-509-9700 ext.5315
-----------------------------------------------------
|