Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!apple!vsi1!daver!mips!keith
From: keith@mips.COM (Keith Garrett)
Newsgroups: comp.arch
Subject: Re: DARPA supercomputer
Message-ID: <17108@gumby.mips.COM>
Date: 12 Apr 89 20:48:04 GMT
References: <2866@uokmax.UUCP> <761@m3.mfci.UUCP>
Reply-To: keith@mips.COM (Keith Garrett)
Distribution: usa
Organization: MIPS Computer Systems, Sunnyvale, CA
Lines: 15

In article <761@m3.mfci.UUCP> rodman@mfci.UUCP (Paul Rodman) writes:
 <Stuff about Cray 3 and GaAs>
>To save on the 3rd dimension they also have to grind down the *thickness*
>of the die as they come from Gigabit, else a basic cpu would be 2 inches
>think, not 1 inch. Gag! what does that do to the net yield?

semiconductor manufacturers have been grinding the backs of of wafers for
years. most (probably all) IC's you can buy today lost material off their
backsides right before being placed in packages. the process is simple and
shouldn't add defects to the active region (there is some evidence that
back grinding traps defects away from the active region, improving yield)
-- 
Keith Garrett        "This is *MY* opinion, OBVIOUSLY"
UUCP: keith@mips.com  or  {ames,decwrl,prls}!mips!keith
USPS: Mips Computer Systems,930 Arques Ave,Sunnyvale,Ca. 94086