Ingemar,

I view temperature as another bonding parameter to be utilized to the greatest benefit of the process and reliability.  [Good speech, eh!]  Although typically, I don't deviate much from established norms, I have gone up to nearly 200°C on some really difficult chips.  See note on die attach materials.

It is actually another form of energy input.

It is an ace in the hole to be used judiciously.  When the crystal can not physically endure ultrasonic energy [like a lot of LEDs], give it more heat and reduce the ultrasonics.

There are always multiple ways to 'skin a cat'.  I try to leave my options open by careful selection of die attach materials, etc. if I can.  Eg - low modulus die attach materials may be great for large die, but can be downright silly for small die.  

If the device simply can not take elevated bonding temperatures - your options are more limited....  :-(  

I don't really view bonding temp as having a great deal to do with annealing/softening the ball bond during bond formation, although it may ... I'm only there for 50-100mS.  I personally believe that control over free air ball formation parameters has slightly more impact.  But even there, there are limited parameters that one can tweak.

Keep us posted with the next installment of the saga

Steve

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge
Sent: Monday, August 25, 2008 11:08 PM
To: [log in to unmask]
Subject: Re: [TN] Wire bonding gurus ohoy!

Trikeman,
thanks for digging in your X-files box. Except for the Taguchi-like 
structure, I'll keep an eye on the +175 Centigrades. 50 degrees more than 
was used for the opto chips. Why 38um wire and not 2um?  Current? Is it 
advantageous to use the thicker wire?
Not a rookie gutter answer either

 
 
THE INFORMATION CONTAINED IN THIS E-MAIL MESSAGE AND ANY ATTACHMENTS SENT FROM GENTEX CORPORATION IS GENTEX CONFIDENTIAL INFORMATION INTENDED ONLY FOR THE PERSONAL USE OF THE INDIVIDUAL OR ENTITY NAMED ABOVE. If you are not the intended recipient, you are hereby notified that any review, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender by return e-mail, and delete this e-mail message and any attachments from your computer. [gntx v.1]

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