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Need info on Endcap cells ?

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pavanks

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I know that endcap cells are placed at the end of each row.
They say they can remove the DRC also by doing this, but how ?
Pls explain in detail.
 

Endcaps normally terminates or ends the followpins at the ends.
It also means, that it is end of the row, if not dangling nets will not be reported.
 
Endcaps normally terminates or ends the followpins at the ends.
It also means, that it is end of the row, if not dangling nets will not be reported.

Can u pls explain in detail?

Thanks
 

End caps does not have any functionality/ or does not carry any timing information with it. Its just the cell. you'll have more updates on this, if you see them in GDS reader.
 

End caps does not have any functionality/ or does not carry any timing information with it. Its just the cell. you'll have more updates on this, if you see them in GDS reader.

I know that, but i need to know the logic behind adding endcap cells?
Can u pls explain the logic here?

Thanks
 

Hi Pavan,

Endcap cells are used for terminating rows as the end of diffusion. These cells are used to fullfill NWELL Antenna requirement. (you can cehck the corresponding rule in your design manual) .
In the design or say few technology normally has special requirements such as latchup rules. In order to make layout DRC and electrically latchup compliant, endcap cells are created specifically for the reason of eliminating these errors.
END CAp cells normally contain only tapping layers N+ and P+, and there layers does not interfere with routing, however, the endcap cell will block any other cells from being placed at that location.
 

Hi Pavan,

Endcap cells are used for terminating rows as the end of diffusion. These cells are used to fullfill NWELL Antenna requirement. (you can cehck the corresponding rule in your design manual) .
In the design or say few technology normally has special requirements such as latchup rules. In order to make layout DRC and electrically latchup compliant, endcap cells are created specifically for the reason of eliminating these errors.
END CAp cells normally contain only tapping layers N+ and P+, and there layers does not interfere with routing, however, the endcap cell will block any other cells from being placed at that location.

Thanks for the explanation. But still i am not getting it clearly :(
Can u explain it with some diagrams if possible?

Thanks
 

End cap cells are preplaced physical only cells that are required to meet certain design rules.
They are placed at the ends of the site rows, and are used in some technology for power distribution.
you shd add End cap cells to the design before any other standard cell is placed, but after hard macros have been placed in floorplan.
i.e, it is placed in a preplaced status, so future placement commands will not move them....

Decap are nothing but Decoupling capacitance.
So adding these decoupling capacitance to a design can help maintain a stable voltage between pwr n gnd when signal nets switch. this can reduce IR drop for power nets and limit bouncing on ground nets....
Well taps are physical only filler cells that are required by some technology libraries to limit resistance between pwr or gnd connections to wells of the substrate.
If poly end cap is not there for a Mos transistor,the drain and source may get short due to improper etching.
 

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