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Oral History – Hans Camenzind
Continued)
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You mentioned the term
“rubylith” as required in the IC design process. How was that used?
There was an Exacto knife
attached to a parallel arm. You
used this to cut out the “runs” (in
the rubylith), and peel off very
carefully the plastic material from the area that’s not supposed to be
there. Next, you photograph that,
reduce it in size. The rubylith mask is about 300X. You had a table that was calibrated in
hundredths of millimeters, still, it was almost impossible - if you had two resistors that had to
match, to make them absolutely identical. It depends on how much patience
you had with that arm.
Nowadays, you do it on the
computer. It is a mathematical
abstraction, and it’s absolutely accurate.
A resistor is five micrometers wide and that means 5.00000. And the second one is exactly the same,
and the accuracy only depends on an apparatus that takes this number and
converts it into a position and shines light on a mask. The biggest step today, if I designed a
new circuit the size of the 555, the design would be about three weeks. I
would not breadboard it – I’d simulate it on a computer, and while doing
that, I can put in all the variations of the components (its called a Monte
Carlo analysis), and they appear in random combinations, and I can be
absolutely sure I’ve included all the production variations. So that’s
number one.
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Oral History – Hans Camenzind
(Continued)
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Number two, I can compare the
circuit diagram with the layout (the layout of course is done on the
computer too), and be 100% certain it is correct. There are no mistakes. I’ve never seen a human being that can
do that. It really takes a
computer.
So, if you used these
modern tools now, how long would the 555 work take?
(In addition to the three
weeks design we just discussed), the layout would take about two days. And then you have to wait. Some companies can make a prototype in
four weeks, and some can take six months. It depends on how busy they
are. I have moved integrated
circuits into production from start to finish, from the day I got the
contract to the day we had 100 pieces, in six weeks. It can be done.
What a change in 30
years!
Yes, and during that time
designing ICs has become much more pleasant. I mean it is really a pleasure to design an IC today. It was a pain in the neck back then (it
was interesting and challenging), but I remember the days, bent over a
light table, checking until you had a backache – it was very
laborious.
Go
To Camenzind Oral History,Page 9
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