I'm a longtime user of Virtuoso for CAD layout but never had to do any Skill programming before. Recenly I've started working on designs that need rotation (from 10 to 170 degrees, in steps of 10 degree), and each rotation would need to be saved to a separate gds file. These are the steps I wish to perform
* select all (all shapes in the layout)
* rotate by x degree, with the center being (0,0)
* output to stream file <streamname>-x.gds
I'm wondering if Skill programming would make it easier to do this? If so, would anyone give me pointers on which functions to call?
A couple of questions:
How big are the devices?
What release are you on?
Here is the quandry, Virtuoso only supports rotations of 90 degrees so you could place an instance of your top chip in another cell with those rotations. If you have to rotate 10 degrees, you have to flatten the database and transform the shapes. In IC6.1 you have dbTransformCellView which will rotate or magnify the shapes in a cell. The issue is that if you database is hierarchical, it needs to be completely flattened and if it is large, there is a lot of data to be rotated. There is also the issue of roundoff when rotating the data,you will need a greater number of DBU per UU (database units per user unit) to compensate for the rotation.
A solution you may want explore with your mask maker is to have them do the rotation for you. Most electronic mask making machines can manipulate the data.
If this is for a MEMS device, you may have small enough data to do the transform but if it is a big device, I would explore the latter solution.
In reply to Austin CAD Guy:
Hi Austin CAD guy,
Thanks for the pointers. I'm on IC6.1, and luckliy my device is small and already flattened. We run the CAD through electron beam lithography - so no masks needed. But the software we use for lithography only allows for 90 degree rotations. So I'm forced to rotate in the CAD software itself.
I will try out the dbTransformCellView. Thanks!