19 Aug
2010
19 Aug
'10
2:41 p.m.
From: jws at jwsss.com
To:
Subject: Re: PDP-1 MCM Modules
Hi
Although there is the heat transfer, we used to use helium in our MCM
packages when at HaL computers. I was always told that we did it for
leak detecting. They had a helium sniffer ( small mass spec ) after sealing the part.
Dwight
what was the basic purpose of the helium?
On 8/18/2010 4:37 PM, William Donzelli wrote:
>> Helium filled?!?!? Must have leaked like crazy.
> The Helium was really just a small player in the whole technology of
> the TCM. By far, most of the heat was conducted away through the
> ceramic substrate and the metal pistons to the water cooled cold
> plate.
This link has a paper by IBM and Honeywell describing MCM's which
used the helium in discussion here.
All of the other discussions I could find are behind various paywalls (ieee,
elsevier, aip, etc.) which I won't pay for. Thnaks to whoever hindawi is
for putting it where it is in google, and also accessible.
this one is apparantly open for reading
http://downloads.hindawi.com/journals/apec/1982/204239.pdf
BTW, I googled for this, and it was on the first page, but there are other
articles
"ibm mcm modules helium"
Jim