Comments on: Why are silicon wafers round, instead of rectangular? http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/ I'm a storyteller. I find cool new things, use them to make my life better, and teach others to do the same. Sat, 05 Jul 2008 10:58:58 +0000 http://wordpress.org/?v=2.5.1 By: Jmartens http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-76066 Jmartens Wed, 02 Jul 2008 00:48:33 +0000 http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-76066 Okay, we are getting closer! The thread/wick example is a good one and makes better sense. I would also love to hear what your BIL has to say....the devil is in the details as the saying goes! I just like to ask why (like an annoying 3 year old kid). I am never satisfied with the status quo. One day, maybe 100 years from now (if we are still using silicon) we'll find a way to make square waffers efficiently and I'll be happy :) Thanks for the discussion, it's always good over here on TinyScreenfuls. Okay, we are getting closer! The thread/wick example is a good one and makes better sense. I would also love to hear what your BIL has to say….the devil is in the details as the saying goes!

I just like to ask why (like an annoying 3 year old kid). I am never satisfied with the status quo. One day, maybe 100 years from now (if we are still using silicon) we’ll find a way to make square waffers efficiently and I’ll be happy :)

Thanks for the discussion, it’s always good over here on TinyScreenfuls.

]]> By: Josh Bancroft http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-76065 Josh Bancroft Wed, 02 Jul 2008 00:42:27 +0000 http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-76065 Jeff, as I understand it, here's how they're made, and why they're round. I could be way off on this. Imagine you start with an infinitely small thread of silicon. Like the wick of a candle. The process for creating the larger "column" of silicon involves rotating that "thread" while silicon is added to it, sort of like the process of dipping a candle. That shape is naturally round, and the wafers are then cut from that solid "column" of silicon. You could make the "column" squared, or the wafers square, by cutting off the rounded parts, but why would you want to waste perfectly usable surface area? My brother in law actually works for one of the companies that supplies Intel with it's silicon wafers. I should call him up and run all this by him, to see if I'm full of crap or not. I hope I'm kind of sort of close! :-) Jeff, as I understand it, here’s how they’re made, and why they’re round. I could be way off on this.

Imagine you start with an infinitely small thread of silicon. Like the wick of a candle. The process for creating the larger “column” of silicon involves rotating that “thread” while silicon is added to it, sort of like the process of dipping a candle. That shape is naturally round, and the wafers are then cut from that solid “column” of silicon.

You could make the “column” squared, or the wafers square, by cutting off the rounded parts, but why would you want to waste perfectly usable surface area?

My brother in law actually works for one of the companies that supplies Intel with it’s silicon wafers. I should call him up and run all this by him, to see if I’m full of crap or not. I hope I’m kind of sort of close! :-)

]]> By: Jmartens http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-76064 Jmartens Wed, 02 Jul 2008 00:30:22 +0000 http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-76064 Great question, thanks for posting it to your blog for answers! However, I think a few commenters have missed the point. Espicially Gerry who says "It’s pretty elementary". The only thing that is elementary, Garry, is your way of thinking. You and Ben appear to assume that to get a rectangle shape that one would cut a square out of the cirlce that is produced (Ben says: "going with a rectangle would require cutting off more of the crystalline structure"). Now THAT is elementary. The question that really should be asked is "why is it inefficient to produce a square waffer rather than a circular waffer?" The only reasons given above are: 1. spinning the waffer (rectangles spin, too) 2. even heating (okay, good point but I am sure a solution could be found even though @Pete calls it "impossible") So before we call something elementary, lets try thinking outside of the box. ...and Josh, no disrespect meant to you, the tone comments just frustate me. I admire the fact that instead of trying to answer yourself, you put it out there for your audience. Great question, thanks for posting it to your blog for answers!

However, I think a few commenters have missed the point. Espicially Gerry who says “It’s pretty elementary”.

The only thing that is elementary, Garry, is your way of thinking. You and Ben appear to assume that to get a rectangle shape that one would cut a square out of the cirlce that is produced (Ben says: “going with a rectangle would require cutting off more of the crystalline structure”). Now THAT is elementary.

The question that really should be asked is “why is it inefficient to produce a square waffer rather than a circular waffer?”

The only reasons given above are:
1. spinning the waffer (rectangles spin, too)
2. even heating (okay, good point but I am sure a solution could be found even though @Pete calls it “impossible”)

So before we call something elementary, lets try thinking outside of the box.

…and Josh, no disrespect meant to you, the tone comments just frustate me. I admire the fact that instead of trying to answer yourself, you put it out there for your audience.

]]> By: IBM e Intel em busca de processadores mais ecológicos :: Fórum PCs http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-49897 IBM e Intel em busca de processadores mais ecológicos :: Fórum PCs Thu, 15 Nov 2007 02:35:15 +0000 http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-49897 <!--%kramer-ref-pre%-->[...] últimos anos, lembro que alguém logo perguntou por que os wafers não podiam ser quadrados. Existem várias explicações para esta pergunta, a começar pelo fato de a areia derretida que chamamos de silício ser moldada em [...]<!--%kramer-ref-post%--> Kramer auto Pingback[...] últimos anos, lembro que alguém logo perguntou por que os wafers não podiam ser quadrados. Existem várias explicações para esta pergunta, a começar pelo fato de a areia derretida que chamamos de silício ser moldada em [...]

]]> By: Looking into Intel's new fab « Scobleizer - Tech Geek Blogger http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-28105 Looking into Intel's new fab « Scobleizer - Tech Geek Blogger Tue, 10 Apr 2007 03:45:13 +0000 http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-28105 <!--%kramer-ref-pre%-->[...] http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/ [...]<!--%kramer-ref-post%--> Kramer auto Pingback[...] http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/ [...]

]]> By: Nathan Zeldes http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-19186 Nathan Zeldes Mon, 22 Jan 2007 17:28:59 +0000 http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-19186 A key process step that uses the round form of the wafer is photoresist application - this is done by spinning the wafer rapidly and dripping the liquid resist at the center; centrifugal force takes care of spreading it evenly. A key process step that uses the round form of the wafer is photoresist application - this is done by spinning the wafer rapidly and dripping the liquid resist at the center; centrifugal force takes care of spreading it evenly.

]]> By: Peter http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-19123 Peter Sun, 21 Jan 2007 16:43:18 +0000 http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-19123 Apart from the already mentioned fact that they are round from the way they are produced, there are also practical problems of making some of the process steps on a square wafer. Even/homogenoues growth of films etc is a major problem as heat is not evenly spread on a wafer (cooler at the edges) and that there might be differences in strain. These problems can partly be dealt with, but using a square wafer would make an even distribution of temperature and stress across the wafer impossible. Apart from the already mentioned fact that they are round from the way they are produced, there are also practical problems of making some of the process steps on a square wafer. Even/homogenoues growth of films etc is a major problem as heat is not evenly spread on a wafer (cooler at the edges) and that there might be differences in strain. These problems can partly be dealt with, but using a square wafer would make an even distribution of temperature and stress across the wafer impossible.

]]> By: Jack Dahlgren http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-16825 Jack Dahlgren Fri, 29 Dec 2006 21:50:39 +0000 http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-16825 Actually they aren't completely round. They have a bit cut off on one side so that they can be aligned with the crystals in the proper direction. Look close and you can see it. Actually they aren’t completely round. They have a bit cut off on one side so that they can be aligned with the crystals in the proper direction. Look close and you can see it.

]]> By: Paul Steenbergen http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-16742 Paul Steenbergen Thu, 28 Dec 2006 15:26:53 +0000 http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-16742 Thank you Ben, this was the answer where I was looking for... And thanks to Josh to post my question on your blog... >Paul Thank you Ben, this was the answer where I was looking for…

And thanks to Josh to post my question on your blog…

>Paul

]]> By: Gerry http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-16721 Gerry Thu, 28 Dec 2006 07:55:45 +0000 http://www.tinyscreenfuls.com/2006/12/why-are-silicon-wafers-round-instead-of-rectangular/#comment-16721 Round wafers, in addition to the process by which they are made, provide the most usable chips per area of wafer cross-section. Sure you lose some around the edges, but you would lose more with a rectangular or other shape. It's pretty elementary. Round wafers, in addition to the process by which they are made, provide the most usable chips per area of wafer cross-section. Sure you lose some around the edges, but you would lose more with a rectangular or other shape. It’s pretty elementary.

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