What should I do if I do not want to route over the cell?

My design contained 4 cascaded nand2 gates, and I want to route only
with metal1 and metal2 layer with cells connected by abuttment.

In the soc encounter, I set CTSMode to topPreferredLayer to 2, and
bottomPreferredLayer to 1, then when routing, there are only metal1
and metal2, which is fine, but the metal1 routing still is on the top
of the cell, which is strange.


How can I solve this problem? Are there any settings that can be done
in the soc encounter, or should I make the whole cell area as blockage
when I generated .lef file from abstract generator?

Thanks in advance!!

Renee

 

renee wrote, on 07/25/08 11:53:

I don't know for certain as I don't really know SOC Encounter, but my gut
feeling would be that you should create a blockage on the layers you want to
block - that's how most P&R programs work.

Andrew.

 

Thank you. I already created cover blockage to block routing over the
cell, but there is still a distance between the blockage and
prBoundary, thus when I route with nanoroute, the wire still extend
the edge of the cell by one-half of the routing wire width. I just
want the wire touch the edge of the cell without extension, and I
tried to add "NOWIREEXTENSIONATPIN ON ;" in the lef file, but it
cannot solve the problem.

What should I do? Is there any setting in the encounter or lef file
that I can do to solve this problem?

Thank you!

 

There is a halo feature in Encounter that you can put on instances
which blocks routing next to the instance. You define the size of the
halo compared to the instances boundry.

Tim