How Big is a Micron? Relative sizes graphic for visual contrast

Jerry Eldred

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Near and dear to my heart, being in the semiconductor industry. As a gauge, When I was first exposed to the semiconductor industry, the smallest dimension (they call it CD - Critical Dimension), was about 1.25 microns. Last I heard, the CD has gotten down to somewhere around 0.08 microns.

And to be a little more confusing, the other small dimension is film thicknesses. In my earliest recollections, those were down to about 1000 Angstroms (an Angstrom, as I recall, is 0.1 nanometers) A nanometer is 1/1000th of a micron. So an Angstrom is 0.0001 microns (1/10,000th of a micron).

In recent years, the gate oxide film thicknesses have gotten down to somewhere around 10 to 50 Angstroms. Tiny stuff. It's pure magic the way they can put all that stuff in a SUB-microscopic area like that. You can't even see a lot of it with a normal microscope. Needs to be an SEM (Scanning Electron Microscope).

Enough rambling. I just had to put in my two cents.

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Interesting. I posted this as I was doing some training some time ago and and I was trying to explain why the job they were doing could not be a 'look at it to see if it's right' - that they had to rely on gages (same thing they taught me when I learned to fly in the late 1960's - trust your instruments). Often it's hard for some people to understand without some type of 'picture' for comparison.

I was looking through some of my stuff and figured I'd post this for others. I have a relative understanding - but that goes back to my college days. With a biology major and with chemistry being a minor, the angstrom unit was everythere. We were looking at the size of stuff at the molecular and atomic level. I never did have access to a SEM, but of course there were pictures (as I remember they always called them pictographs) in texts - of course that was 25 years ago so technology has come a long way.

In your world, Jerry, this is everything as trace sizes shrink and the limits of the photomask process are reached. As I remember, they went to - or are going to - x-ray or something. Haven't been following closely, really, but in chip design and production it's a major player.

Just a post for thought.

Geoff Cotton

Quite Involved in Discussions
Gnats Knacker - GK

The smallest dimension in the England is the GK (better known as the Gnats Knacker), the Gnats Nacker is a term used by many engineers in England but as yet the National Physice Lab. have not been able to determin its size, but when you hear engineers talk in GK's you get the impression it must be really small..:biglaugh:

(Just having a laugh) :vfunny:

Ryan Wilde

American Class 2 Blocks --> ANSI B89.1.9

More perspective for you dimensional folks. The tolerance of your gage blocks (based on American Class 2 blocks, soon to change in the new ANSI B89.1.9) is 1/10th of that micron. (Which, BTW, is an old term, and the accepted term is now micrometer [µm]. This adds to a wonderful new array of confusion when writing, since the spelling [but not the pronunciation] is shared with a very common instrument. One may read a micrometer WITH a micrometer - welcome to the wonderful world of English.)


PS - Geoff, we have a term much like GK, but I would not dare type the initials, let alone what they stand for. Let us not forget that we Americans tend to lean toward being crude rather than witty ;)


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Attached is my favorite illustration. Came from back in the day when dirt was a problem with those floppy things that you fed computers. :cool:


  • micron.jpg
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Stop X-bar/R Madness!!
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A Micron is huge in today's semiconductor technology. We are currently at the 32 nanometers, where 1000 Nanometers = 1 Micron. Engineering samples already here...

It's not all that odd in precision machining, etiher. The proper charting of a characteristic will allow the tool wear to be determined by the slope to nanometers per part.

Of course, it has to be charted and controlled correctly.:cool:
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