[SOLVED] What do notch rules mean in layout design?

Does anyone know what notch rules exactly mean in layout design?

I googled but got pretty little detailed information. Hopefully, some experienced engineers here know about it? Thanks.

Hi Please check the attached fig.

Now the general Notch rule is some thing like this.
> space between 2 segment of U or O shaped metal/od/poly (notch only) >=0.18

so in the diagram "I" spacing.. that's the part of the Notch rule.

What rules say that when ever there is any notch in the layer then the spacing rule should follow the corresponding rules. This spacing is different from the normal spacing rule that's the reason foundry has a specific rule for this.

Let me know in case if you any further query.

Thanks, Birdy! I guess this rule is mainly for active and well regions? Because, as far as I know, the metal layers typically have preferred routing directions and can only be routed in one direction.

hi Zihan_gao,

You are right , but there are cases in Metal1 .. where some time you have to use this..

birdy123 said:

View attachment 60763

Hi Please check the attached fig.

Now the general Notch rule is some thing like this.
> space between 2 segment of U or O shaped metal/od/poly (notch only) >=0.18

so in the diagram "I" spacing.. that's the part of the Notch rule.

What rules say that when ever there is any notch in the layer then the spacing rule should follow the corresponding rules. This spacing is different from the normal spacing rule that's the reason foundry has a specific rule for this.

Let me know in case if you any further query.

Click to expand...

Hi Birdy,

Can you pls tell more clearly what exactly is the difference between notch and spacing.

ramuknura said:

Hi Birdy,

Can you pls tell more clearly what exactly is the difference between notch and spacing.

Click to expand...

Notch means the same net and spacing is between diff nets. Hope its clear.

And there are many instances where u need to go for non default routing in the lower metal layers coz of less resource in the lower metals as u need to go to lower metal layers for connecting to the std cells.

pavanks said:

Notch means the same net and spacing is between diff nets. Hope its clear.

And there are many instances where u need to go for non default routing in the lower metal layers coz of less resource in the lower metals as u need to go to lower metal layers for connecting to the std cells.

Click to expand...

Thank you pavanks. it was simple and clear.