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Why we cant making finger length for layout

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pbalamuruga6589@gmail.com

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Hello All,

We are always doing finger for width..Why we did not use for length..

Eg

If W=8u & L=1u means we are doing W=4u nf=2 and L=1u (always) ... why we are not follow L=0.5u nf=2 ?

If anyone know about please give me ans..
 

Hello
In the fabrication process the masks are made of fixed poly lengths.If you are working on any node technology the poly lengths will be same for all the transistors you have used,Say if you are working on 45nm technology than all the transistor sizes poly gate will be 45 itself.the reason for fingering is mainly to make the poly resistance less.
 

Hi Anand,

Thanks, i can understand your answer..the fabrication process all poly length same (all technology).. In analog circuits we may use L=1u why we cant divide the length = 500n and nf=2

Thanks

Bala
 

hey bala,

width splitting is basically a concept used for standard cell design...
this is called fingering
so this is done to make ur device faster..
and only width is splitted because standard cells are those cells which should have a fixed heigth and same length and u cant go beyond a particular height ..
so if the height of the standard cell is supposed to be 10 and ur layout heigth is 100 then we break the width into 10 pieces or fingers...

this means that we dont have an option of splitting lengths as far as standard cells are concerned
 

pbalamuruga6589@gmail.com said:
Hi Anand,

Thanks, i can understand your answer..the fabrication process all poly length same (all technology).. In analog circuits we may use L=1u why we cant divide the length = 500n and nf=2

Thanks

Bala
Click to expand...


If you do so than the technology you are working will not be 1u length technology it will be 500n technology.
 

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