12 Mar
2003
12 Mar
'03
11:51 a.m.
Hi
These are usually made on a glass plate. They look
like a larger version of only one of the dies of a wafer.
Some are actual size but most are done with steppers now days.
The glass has a thin metal coat on one side ( mirror looking ).
I think they use chromium but I don't recall. You can see
that layer's detail by holding it up to the light. The metal
has been remove in places. It is kind of like a negative and
used the same way.
The ones for things like uP's of today, include a set of
about 30 or 40 for different parts of the processing. A full
set of these cost about 0.5 M$ to make.
Dwight
From: "Chandra Bajpai"
<cbajpai(a)attbi.com>
I got to ask this...what's a wafer mask...what's it look like?
-Chandra
-----Original Message-----
From: cctalk-admin(a)classiccmp.org [mailto:cctalk-admin@classiccmp.org]
On Behalf Of Hans Franke
Sent: Wednesday, March 12, 2003 6:22 AM
To: cctalk(a)classiccmp.org
Subject: RE: collecting silicon wafers
1. Stamps are printed in vast numbers
2. They are used and, in most cases, eventually destroyed
3. They are difficult to forge (convincingly)
4. Most are virtually worthless
5. A few a almost priceless
6. Many are beautiful
7. They have an inherent research interest - printing varieties,
flaws, rarities, historical interest etc.
8. They are (usually) considered most valuable unused and even
more valuable in an unbroken sheet.
[...]
The whole idea of wafer collecting got something to it, although
I think the stamp reference is a bit far fetched.
Gruss
H.
BTW: I realy love wafer masks ... they are just a bit hard to find.
So if one of y'all (sp?) got some laying around ...
--
VCF Europa 4.0 am 03./04. Mai 2003 in Muenchen
http://www.vcfe.org/