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| Date: | Wed, 25 May 2005 09:14:51 +0200 |
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Thank you for help. Just a few answers, but from very experienced persons.
The answer is, that power devices like below ought to have a dense and good
metallisation no thinner than 2 micrometers.
Ingemar Hernefjord
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Ingemar Hernefjord
(KC/EMW)
Sent: den 20 maj 2005 15:38
To: [log in to unmask]
Subject: [TN] Semi q about power zeners
Not exactly a PWB matter, but I know about the width of knowhow in this society. So, here we go:
bolted zener, 1200 A us capability. Chip is soldered on copper stud, upside of chip is soldered to a 1 mm thick pin. The end of this pin is bent and flat. Now, all know that itīs important to spread the instant current as fast and evenly as possible throughout the chip area, and without voids in the solder joint. If this isn't fulfilled, you may get metal filaments into the chip and then a channel burnt through the die. Now comes the question: anyone with experience from front metallisation thickness on such high power dies? In my opinion, the metallisation ought to be several micrometers, but we have a case with just some 200 nanometers. The wafer makers do not give clear answer, or no answer at all. Well reputed IRC got some 100 technical papers, many of which are very advanced...but not one line about the front metal vs. current.
Anny Sir Yeastchon?
Ingemar Hernefjord
Ericsson Microwave Systems
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