Change the origin of a via/contact to avoid off-grids.

Hello,

I am in the process of creating a new PDK. One of the things that need to be set-up is for layout to be able to create contact/vias's. In the technology file, standard via's can be defined. I want to use that build-in functionality to create the contacts/via's.

Here are some of the specifications of the process:

• Manufacturing and design grid = 0.01um
• CONTACT size (square) = 0.35um
• ACTIVE enclosure of CONTACT = 0.1um
• METAL1 enclosure of CONTACT = 0.12um
• VIAx openings are an odd value as well.

As is easily seen is that with a CONTACT of 0.35 and grid of 0.01 AND the origin of a standard via in the center, the edges of the CONTACT, ACTIVE and METAL1 layers will all be off-grid (0.35 / 2 = 0.175). This is a problem of course. The size of the CONTACT can not be changed (we have had many discussions about this, but according to the process engineers this is the optimal size).

A contact/via which is on-grid can be generated if the origin is not in the center, but in one of the corners. However, I don't see a variable that can control this.

My question is:
How do I define this contact using the standard via definition format in the technology file, and still get a layout that is on-grid?

With kind regards,

Sjoerd Herder