Phil,

You ask some very good questions for which I don't have an answer either,
but all the 'biggies' used them as well.

I can tell you that when we used GelPacs for transport and handling of bare,
we experienced no observed ESD or contamination problems.  In the cases of
GelPac packed die, they were generically highly expensive, extremely ESD
sensitive, extremely small [<0.005-0.010" square], or extremely large
[>0.400 x 0.400"], and in many cases 'gold backed'.

We used both the vacuum release and the generic static gelpac, depending
upon die size.  Always used ionized air flow during placement or removal
in/from the gelpac.

From a microelectronics standpoint, gold backed die provide a less than
optimum surface to bond to in the first place.  Were there contamination on
the back surface of the die, it could be catastrophic.

It is like saying they are okay because everyone uses them - which is an
argument that I don't particularly care for either, but is all I have to
offer at the moment.

If you come up with any additional [substantive] information I would very
much like to learn from it as well.

Respectfully,


Steve Creswick
http://www.linkedin.com/in/stevencreswick



-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Bavaro
Sent: Friday, March 04, 2011 6:20 PM
To: [log in to unmask]
Subject: [TN] Gel-Pak and ESD

Has anyone been able to approve the patented Gel-Pak containers for
packaging of ESD sensitive items?

I found a supplier putting ESD sensitive ICs into these after tinning
and lead forming, and I cannot see how this is not a bad thing.
 

I realize the outer packaging is made from ESD approved materials, but
the Gel-Pak itself is fully insulative wrt surface/volume resistivity.

 

On the other hand, I see that one of the advertised uses for the Gel-Pak
is wafer/die packaging.

 

I could understand perhaps if the Gel-Pak loading and unloading was
performed under forced air ionizers, but in any other situation, I see
components leads and a sticky 1014 insulator as being the definition of
an ESD event.

 

I am also concerned about putting solderable surfaces onto the
"proprietary" Gel-Pak material since I don't know what it is.

  

 

Phil

 

 


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