Hi Doug,
Hope the new job is what you hoped for.
We both know I'm no rocket scientist, or even a chemist, but I think I have
enough pieces to figure this one out, or at least get a lively discussion
going!?
Al2O3 is what I know as anodizing. In its raw state it is very porous, 612
billion pores per square inch.
see http://www.pioneermetal.com/index2.html
The final step of anodizing is to seal all these pores, by placing it in
various solutions, or DI H2O.
Since bonding is affected by the ability of the adhesive to find sites to
adhere to, the raw part should bond better than the sealed part. If the
part is full sealed, offering little in the way of bond sites, you have what
I call sticktion, not adhesion. If the part fails at the bondline, leaving
two surfaces with little or no evidence of material from the mating
material, you had sticktion. If the break occurs in either the adhesive, or
the base materials, then you have a good bond.
There was a nice MIL-HDBK out for adhesive bonding. I found it using the
ASSIST online at http://www.dsp.dla.mil/.
Look for MIL-HDBK-691 Adhesive Bonding. Its been helpful to me since my
days building B-1B bombers in the early-1980's. I'd send you a copy, but a
14 meg PDF makes some e-mail systems choke.
Hope this helps,
Steve Mikell
-----Original Message-----
From: Douglas Pauls [mailto:[log in to unmask]]
Sent: Friday, February 02, 2001 3:59 PM
To: [log in to unmask]
Subject: [TN] DI water and aluminum bond pads
Mr. Hillman and I are currently having a running debate on the reasons for
differing bond pull strengths on silicon die. Do any of you out there have
an experience with high resistivity water (e.g. 18 megohm-cm) degrading
bondability of Al2O3 bond pads? We see poorer bonding at high resistivity
than we do at lower resistivity rinse water. One theory is that the
aggressive DI water causes a thicker oxide layer, hence poorer bonding.
Any papers on this topic?
Doug Pauls
Rockwell Collins
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