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RobertOToole
Joined: 17 Jan 2013
Posts: 916
Location: United States
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 Posted: Sun Aug 26, 2018 9:38 am Post subject: |
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| Lou Jost wrote: | | I really like that you included the Mag.X. It is good to see what is possible, not just what is practical or easy. I lust after that lens! |
Its gets worse once you find one! Now I really want the 8x/0.32 version Mag.x!
Super APO, Double Telecentricity, f/1.4, effective 12.5 at 8x. The Mity 7.5 is f/2.1 and Eff 17.86!
The 8x/0.32 would be pretty awesome pushed down to 5x!
Robert |
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RobertOToole
Joined: 17 Jan 2013
Posts: 916
Location: United States
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| Posted: Sun Aug 26, 2018 9:47 am Post subject: |
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| ray_parkhurst wrote: | | RobertOToole wrote: | ...
The Metal markings look like they have a lot more depth than the poly marks. |
Poly is below contact, which is below the metals. Poly and contact are both doped, so are quite thin, which is why the resolution is better. Metals are thick, so cannot be spaced as closely, and have worse resolution due to alignment, etching variation (under or over etching producing undercut or shorts), and grain boundary issues. Design rules for line spacings get larger as you go higher. |
Thanks for the input Ray.
Any idea the difference in height could be between Poly and Metal?
If those are micron width markings, whats the height, fractions of a Nm?
I am a little surprised that the DOF of the Mity 50x got it all in one image.
Robert |
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ray_parkhurst
Joined: 20 Nov 2010
Posts: 1643
Location: Santa Clara, CA, USA
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| Posted: Sun Aug 26, 2018 9:52 am Post subject: |
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| RobertOToole wrote: | | ray_parkhurst wrote: | | RobertOToole wrote: | ...
The Metal markings look like they have a lot more depth than the poly marks. |
Poly is below contact, which is below the metals. Poly and contact are both doped, so are quite thin, which is why the resolution is better. Metals are thick, so cannot be spaced as closely, and have worse resolution due to alignment, etching variation (under or over etching producing undercut or shorts), and grain boundary issues. Design rules for line spacings get larger as you go higher. |
Thanks for the input Ray.
Any idea the difference in height could be between Poly and Metal?
If those are micron width markings, whats the height, fractions of a Nm?
I am a little surprised that the DOF of the Mity 50x got it all in one image.
Robert |
Poly and Contact are sub-micron. Metals can be up to a couple microns thick but typically average around 1um. So if you have a 4-metal system, you're probably talking total height of a few um. |
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mawyatt
Joined: 22 Aug 2013
Posts: 1595
Location: Clearwater
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| Posted: Sun Aug 26, 2018 10:00 am Post subject: |
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Robert, Ray,
Sometimes processes have a thick and thin top metal, the thick is often used for inductors to improve the quality factor. The thick can be 5 microns.
During the era of this wafer we utilized a new process at Bell Labs that had a special thick gold top metal, it was 25 microns thick!! You can guess what it was used for!!
Best,
_________________
Research is like a treasure hunt, you don't know where to look or what you'll find!
~Mike |
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ray_parkhurst
Joined: 20 Nov 2010
Posts: 1643
Location: Santa Clara, CA, USA
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| Posted: Sun Aug 26, 2018 10:09 am Post subject: |
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| mawyatt wrote: | Robert, Ray,
Sometimes processes have a thick and thin top metal, the thick is often used for inductors to improve the quality factor. The thick can be 5 microns.
During the era of this wafer we utilized a new process at Bell Labs that had a special thick gold top metal, it was 25 microns thick!! You can guess what it was used for!!
Best, |
In my HEMT processes, we top-out around 3um thick for gold. As thickness increases, width and spacing rules must also increase, so these thick metals are only used for high current routing on the very top layers.
By appearance, the process for this wafer probably did not use thick metals, and likely only Al an alloy, so I'd still expect total thickness of only a few um at most. |
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AlxndrBrg
Joined: 14 Jan 2014
Posts: 47
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| Posted: Mon Aug 27, 2018 6:44 am Post subject: |
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Great stuff - I am kinda missing the Lomo 3,7x though, from what I recall it handles being pushed down quite far, would be interesting to see how it competes with these real glass monsters  |
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Lou Jost
Joined: 04 Sep 2015
Posts: 2714
Location: Ecuador
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| Posted: Mon Aug 27, 2018 6:57 am Post subject: |
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I've been using the Lomo on FF where it does very well (it is not so great on MFT). I tested it against the DiMage at 4x on FF and the Lomo won, even in the corners.
_________________
Lou Jost
www.ecomingafoundation.wordpress.com
www.loujost.com |
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ray_parkhurst
Joined: 20 Nov 2010
Posts: 1643
Location: Santa Clara, CA, USA
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| Posted: Wed Aug 29, 2018 10:00 am Post subject: |
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| AlxndrBrg wrote: | | Great stuff - I am kinda missing the Lomo 3,7x though, from what I recall it handles being pushed down quite far, would be interesting to see how it competes with these real glass monsters |
I was wondering same thing. It should do well due to the low CA, though its NA 0.11 likely won't be competitive from raw resolution perspective. Same situation for the Inspec.x 105mm f4 3.5x lens with NA 0.1. Great coverage, low CAs, but won't beat the resolution of a high NA objective. |
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