Arny Krueger wrote:

I guess its possible its bigger than some of the smaller components
in a classical watch. (thats a guess though).

Not at all.

How big are the features on a typical mask used in photolithography then?

the chip is produced by shrinking the mask optically onto the silicon
wafer...


Yes, which means that the detail is very fine - tolerances on the order of
wavelengths of light and even X-rays.

Indeed - but is the mask that fine or is the image focued through a much
bigger mask?

I dunno about you, but the 1.99ukp cheapies dont seem to last more
than a year, maybe three before the strap goes...

I go with *quality* product - Timex ;-)

;-)

"Ian Molton" wrote in message

Arny Krueger wrote:

I guess its possible its bigger than some of the smaller components
in a classical watch. (thats a guess though).

Not at all.

How big are the features on a typical mask used in photolithography
then?

At one time they were quite large. In some processes there is no mask - the
pattern is written directly on the wafer.

the chip is produced by shrinking the mask optically onto the
silicon wafer...


Yes, which means that the detail is very fine - tolerances on the
order of wavelengths of light and even X-rays.

Indeed - but is the mask that fine or is the image focued through a
much bigger mask?

If a mask is used, its far larger than the finished product.

Arny Krueger wrote:
"Ian Molton" wrote in message


How big are the features on a typical mask used in photolithography
then?

At one time they were quite large. In some processes there is no mask - the
pattern is written directly on the wafer.

Interesting. when you say directly, howso? burnt by a laser and etched?

Indeed - but is the mask that fine or is the image focued through a
much bigger mask?

If a mask is used, its far larger than the finished product.

Out of curiostiy, how big?

"Ian Molton" wrote in message

Arny Krueger wrote:
"Ian Molton" wrote in message


How big are the features on a typical mask used in photolithography
then?

At one time they were quite large. In some processes there is no
mask - the pattern is written directly on the wafer.

Interesting. when you say directly, howso? burnt by a laser and etched?

http://www.advantest.co.jp/products/...en-index.shtml


Indeed - but is the mask that fine or is the image focued through a
much bigger mask?

If a mask is used, its far larger than the finished product.

Out of curiostiy, how big?

I've seen masks for one chip that were wall-sized.

However, current technology seems to be smaller:

http://www.photoplotstore.com/pages/photomasks.html

Arny Krueger wrote:

Interesting. when you say directly, howso? burnt by a laser and etched?

http://www.advantest.co.jp/products/...en-index.shtml

Thanks.

I've seen masks for one chip that were wall-sized.

what was the feature size on the mask ?

However, current technology seems to be smaller:

http://www.photoplotstore.com/pages/photomasks.html

:-)

"Ian Molton" wrote in message

Arny Krueger wrote:

I've seen masks for one chip that were wall-sized.

what was the feature size on the mask ?

A few times the width of an ordinary drafting pen.

I think that was the point - at the time they were just plotting these out
on standard drafting plotters.

Arny Krueger wrote:
"Ian Molton" wrote in message


Arny Krueger wrote:


I've seen masks for one chip that were wall-sized.

what was the feature size on the mask ?


A few times the width of an ordinary drafting pen.

I think that was the point - at the time they were just plotting these out
on standard drafting plotters.

IOW the tolerances werent really any better than a good mechanical watch
(on the mask).

I suppose the alignment mechanisms for the die would be far better
quality than the mechs in the watch but I suppose its a question of how
far back in the process you want to go ;-)