Q: Is it possible to perform a DRC check on portions rather than on the whole circuit useful when only 2 or 3 errors to fix ?


A: You may clip out the required piece of layout (menu Tools>>Clip Out). This operation preserves coordinates and hierarchy of instances that were not cut during clipping. Then you may run DRC on the clip and see if there are any errors. There are two problems:

  • at the border fringe errors appear that are not actually present in the original layout;
  • there is no direct access to erratic objects in the original layout: you must look at the coordinates where the error is reported in the clip and then find the same place in the original (You may use the operation Edit>>Position Cursor). Therefore you must proceed as follows.

Figure 1.

  • Open two windows: for original layout and for clipped piece;
  • Go to Clip window, run DRC script and load errors for it.
  • Go to next error, place cursor at an appropriate point and read the coordinates of cursor position;
  • Go into the window with the original layout, make the zoom appropriate to see details;
  • Press Ctrl-P and enter the cursor position read in the clip window and press Enter. This will place cursor in the same position and you will easily find the objects generating the error shown in the Clip window.

Q: In the Layer Setup I added a new layer and placed it first. But the layout window is not redrawn, and in fact the new layer is shown last at the Layer Bar.


A: The Layer bar shows the order of layers in the current view. It may be different from the default order defined in the technology file (and shown in the Layer Setup list). To restore the order of layers to the technology default, click the "Default order" button at the layer bar.

Q: Our department purchased 9 copies of Expert for designers and 2 copies of Savage for verification team to run full-chip DRC. Can I run Savage on the server and then correct DRC errors on my own PC?

A:Yes, you can, provided the following requirements are satisfied.

  • the projects on both computers must be in eif format;
  • their cell hierarchy must be identical (but geometry in cells may be edited, e.g., some DRC errors corrected).

The result a of DRC run is an error database with extension .edb . It lies in the subdirectory with the name <ProjName>.DRC, where <ProjName> is the name of the checked .eif file.

You must create the same <ProjName>.DRC subdirectory in the directory of your computer where your gds/eif file lies and copy the .edb file from Savage server into it.

After that you may process DRC errors within Expert as usual, i.e.,

  • load <ProjName>.eif
  • load error database by menu command Built-in DRC>>Load Errors