Silicon Wafers

[jrz126]

I noticed on Ebay that several people are selling the silicon wafers that IC's and such are made of. Is there any use for these, or are they just for show? here's one:
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[williB]

i think it would be cool to own one..but useful .. i dont think so..

 

[samcheetah]

it would make a great decoration peice. or better yet it would serve great as a paper weight on your work table :lol: think of all the people who will get impressed :wink:

but seriously you cant do anything with a wafer if u dont have a lab like the semiconductor manufacturers have. you have the wafer from a fab but you have to put it in a package for it to be useful. and this work is extremely high tech.

 

[evandude]

they won't be any good anyway. once they're in open air they're basically rendered useless... any dust will ruin them.

when i was at work this summer i would sometimes amuse myself by dropping junk wafers into a bucket and watching them smash... it is quite amusing... since silicon is a lot like glass they break like glass.

it was funny when my boss dropped one into the bucket, it hit the rim, and shattered all over the floor. everyone liked that.

anyway, probably a little pricy to be throwing them around if you actually have to BUY them though

 

[Dean Huster]

I don't know that it's so much the dust that ruins the wafers (they're usually washed with DI water between each portion of the fab process) but the chemical reactions that occur with the atmosphere.

Sand to Circuit I believe is the name of a video that's a pretty good overview of the steps in making a typical MSI IC.

Texax State Tech in Waco had geared up back around 1986 or so for making ICs. Being a school, their equipment was donated and was a few generations behind leading edge stuff, so their output was of low-density ICs and of low yield, but at least they were doing it and able to train students in the technology in a state where IC production and design was at the time pretty much centered with Motorola, Texas Instruments and others.

Monsanto had a silicon wafer manufacturing plant in St. Peters, Missouri back in the 1970s and 1980s, since sold to another company, but I took a tour through there that was very interesting. Got the "end butt" of a silicon ingot as a memento of the trip and it makes a great paper weight and conversation piece. I've never had anyone, even any electronics students or electronics teachers, who've ever been able to guess what it was.

Dean

 

[evandude]

actually... i worked in the wafer test area of a semiconductor plant over the past 2 summers... the air in there is just filtered to remove dust. during the fab process the dust still is a huge problem, but you have to consider how little dust there is in the atmosphere in the clean room...

in the wafer sort, where i worked, the dust isn't as big a problem because the wafer is already fabbed and finished... but dust is still a problem... it's still a clean room, just not nearly as clean as the fab... no full bunny suits, but we still had to wear gloves, smocks, booties, and head and face coverings. and dust definitely can ruin ICs on a wafer, it's just not as significant. but wafers that have seen more time out in the open tend to have higher failure rates due in large part to dust, and if you actually took one out into non-filtered air... forget about getting a whole lot of good, working parts off it :wink:
and if someone touches it... you can forget about it. watching wafers being tested, you can always identify fingerprints by the fact that all the die that were touched are invariably failing... which makes it even more amusing when you get a whole handprint or something!

 

[spuffock]

If you can get a silicon slice before the circuitry is made, it will make a neat output window for your light- the -neighbours-arse -at- a- mile carbon dioxide laser.