Why are CPU wafers circular?

[Philippine Mango]

Like why are the wafers in which CPUs are cut out are wafers? Is there a particular reason especially because of the fact that CPUs are squares?

 

[stevty2889]

http://forums.anandtech.com/messageview.aspx?catid=28&threadid=1713248

Wow, two people asking that same question on the same day??

 

[microAmp]

They're round because it's easier to play wafer bowling than if it were a square or some other geometry.

 

[Keysplayr]

Originally posted by: microAmp
They're round because it's easier to play wafer bowling than if it were a square or some other geometry.

Actually a pretty good question. If the wafers were square, there would be virtually 100% used. In the circular wafer, every core that is produced around the circumference of the wafer is incomplete or "cut" and unusable. But I do believe the wasted material is recycled for the next batch. I'm sure there is a reason they are circular though. I think I'll take a look at the other thread to see if they have an answer in there.

 

[klah]

http://www.tocera.co.jp/en/products/wafer/process.html

 

[jiffylube1024]

Originally posted by: keysplayr2003

Originally posted by: microAmp
They're round because it's easier to play wafer bowling than if it were a square or some other geometry.

Actually a pretty good question. If the wafers were square, there would be virtually 100% used. In the circular wafer, every core that is produced around the circumference of the wafer is incomplete or "cut" and unusable. But I do believe the wasted material is recycled for the next batch. I'm sure there is a reason they are circular though. I think I'll take a look at the other thread to see if they have an answer in there.

As said in the other post, you just can't make or 'grow' square wafers. The entire manufacturing process of the silicon involves heat and rotation AFAIK.

The real question is: how do they get the caramel in the caramilk bar? 😉