Gracias Steven,
any hand is appreciated. Will send a jpeg to you illustrating what Tekelec think is the optimal way of connecting that creep. Will let you know, brother. By the way you really have a thriller with those two, G&B, personally like Clinton better.
Thanks again
Ingemar
-----Original Message-----
From: Creswick [mailto:[log in to unmask]]
Sent: den 8 november 2000 03:53
To: [log in to unmask]
Subject: [TN] TN: PIN doide bonding tab
Ingemar,
Can't say that I have done what you describe, but it makes sense. Could you
use another AuSn preform to attach a thin (say, <0.1 mm) NiAu plated kovar
(or CuMoCu, CuMo, CuAg, etc.) disk to the upper surface at the same time as
soldering the diode to the heat spreader?
Assuming the "heat spreader" is not a huge structure, or part of the final
package, one could easily perform this operation in large quantities in a
good atmosphere reflow furnace (or Scientific Sealing Technology
<http://www.sst-tech.com/> vacuum reflow unit).
Here in the States, I would call SPM (now called SEMX)
<http://www.semx.com/index2.html>
or SemiAlloys <http://www.semialloys.com/index.htm> - possibly getting the
Au/Sn preform tacked to the disk like an old fashioned combo-lid. Many
times, these guys will sell the disks in tape and reel format, if that helps
you.
If you have ribbon bonding capability at that particular point in the
process, could you do that instead of introducing a 'new' bonding tab on top
of the device? Would the extra capacitance effect your circuit function?
Hope I may have helped somewhat. If you get a chance, let me know what you
end up doing.
Steven Creswick - CTS RF Integrated Modules
<As there are a lot of microwave guys out there also, I take the opportunity
<to ask following: small PIN diode chip (round bond area < 75 mil dia )
<AuSn'ed on CuMo heatspreader. For withstanding maximum current we parallel
<many 25 micron bond wires. Now, the bond gold is only some 1 micron thick,
<and I have a feeling that many out there use to presolder a metal stud
<firstly onto the chip, and THEN make wirebonding on that stud. This way you
<gain two purposes: spread current more evenly from bond wires into p+ and
<get better wire bonding conditions. Q: if there is someone making same way,
<what studs do you mount and who sells them?
<Sorry for such faraway q from copper and epoxy, but need some help.
<Typically for Creswick and like...
<Tx>advance
<Ingemar Hernefjord
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