[SOLVED] Short violations in Innovus (due to special route)

[Fati_hv]

Hello all,

I hope someone can help.
I have short violations in my low power design.
They are happening inside my power domain (i have an internal power net that is routed by Special Route in the power domain), and it happens with Tap Cells, Encap cells and Fillers only. Power swicthes and regs are not having shorts.
I don't understand why this is happening. I tried adding connectGlobalNet for the power domain and the internal power net, but it did not fix it.

Any advice?

 

[ThisIsNotSam]

Hello all,

I hope someone can help.
I have short violations in my low power design.
They are happening inside my power domain (i have an internal power net that is routed by Special Route in the power domain), and it happens with Tap Cells, Encap cells and Fillers only. Power swicthes and regs are not having shorts.
I don't understand why this is happening. I tried adding connectGlobalNet for the power domain and the internal power net, but it did not fix it.

Any advice?

- check global net connections twice, and then check again. I don't understand your description of this internal power net and why that would be a problem.
- run real DRC, don't trust Innovus DRC.

 

[Fati_hv]

Hello.
Just to explain what i meant by an internal power net:
I am doing power gating, which means that my power domain can be switched off using power switches, and the power net used inside the power domain is different than the main VDD used for the top. It is an internal power net that is the output of the power switches --> VDD_SW1.

Also, i don't understand why only tapcells, endcap cells and fillers are having shorts, while other standard cells inside the domain are not shorting.

This is my globalNetConnect piece of the script, maybe i should do it differently?

globalNetConnect VDD -type tiehi
globalNetConnect VSS -type tielo
globalNetConnect VDD -type pgpin -pin VDD -inst {}
globalNetConnect VSS -type pgpin -pin VSS -inst {}
globalNetConnect VDD -type pgpin -pin VDD -autoTie
globalNetConnect VSS -type pgpin -pin VSS -autoTie

globalNetConnect VDD_SW1 -type pgpin -pin VDD -region {4 4 12 10} -override
globalNetConnect VDD_SW2 -type net -pin VDD -powerDomain phypri -override

There are not shorts outside of the power domain, in the top.

I will try to run DRC using pvs now though, as you suggested.

 

[ThisIsNotSam]

Also, i don't understand why only tapcells, endcap cells and fillers are having shorts, while other standard cells inside the domain are not shorting.

Check the well connections for these cells. Make sure the pins are named the same way as in the std cells. Just a hunch.

 

[Fati_hv]

Check the well connections for these cells. Make sure the pins are named the same way as in the std cells. Just a hunch.

I fixed it!!
Thanks for the help.
It turned out it was actually due to other violations around the block. Once i decided to move past that violation and fix the others, this one went away too.
But thanks for helping!