What is off grid error and how to eliminate it?

Hi friends

What is offgrid error ?How can i eliminate it ?


Thanks
siva

off-grid layout

Hi siva ,off-grid error is something like your drawn layer is not allined with the grid settings you have.you can just add a polygon of same layer at those corners.
to avoid this check ur grid before you modify your layout.
rgs,
bollu

layout off grid

hi,
if u seen your deck/techfile we can see the manufacturing grid assigned to some value like 0.005.
when u start doing layout ,u have to set the layout grid to this value specified.otherwise while exporting GDS you find errors like offgrid error.
this MFG indicates the resolution of the lithographic chuck .

ads offgrid error

what layout editor you use ?
if you have only some wires out off grid is not a big problem . in case you have some cells reference out off grid you can consider this a big problem

off grid error

it refers to the resolution at the manufacturing equipment at the fab.

it varies from fab to fab and pdk to pdk.

before starting the layout u need to do some initial settings change in the option DISPLAY and save it.

if u get an off grid error just write a small script to change the grid of the layers which are having errors.

resolution drc offgrid

hi YESH_23

if u get an off grid error just write a small script to change the grid of the layers which are having errors.

Click to expand...

how to get rid off this error from VLE ?? suppose i have a cell with off grid error then how to remove it without disturbing other layout ?

off grid error skill

When GDSII or appropriate layout file is sent for Fab, Mask is created from the GDSII. Mask is prepared by putting "black dotes" on a special glass. If the grid is not clear, then the tool which puts those dotes cannot work. (Simply put).

So you Have to Move the Layout to one of the dotes in the Virtuoso Layout Editor.

The problem while "re-gridding" is that the dotes may not be in their minimum value specified in the TechFile. So, goto OPTIONS --> DISPLAY . In the "Minor Spacing", put the minimum vlaue, say 0.05 for 0.35um or 0.005 for 0.18um tech. Then check the locations where you have off-grid error, move it to the right location.

To vbhupendra: You have to move it. There is no other way. I think I had a SKILL script for automatically moving the whole layout to 'Grid'. If I find it, I will post it.

Srivats

P.S.: It is very irritating to look hundreds of grid-errors. You can use an avSwitch option in Assura DRC deck so that you can "switch it OFF" (Assura DRC GUI has Switches TAB) and look at them after you have cleared other errors.
However, it is recommended to clean them at first DRC error run itself.