• Analog Custom Design & Analysis Examples

008_create_rectangles : Generate Array of Rectangles

Minimum Required Version : Expert 4.14.0.R, Guardian 4.14.0.R

Since the advent of deep-micron processes, many dummy metal patterns are added in layout designs for planarization. They are created as regularly aligned based on some rules, and usually created by a DRC tool.

Correspondingly, Guardian DRC provides the command Create_Rectangles to create an array of rectangles with specified dimensions and spacing.

The following script is an example of how to create a dummy metal pattern using this command:

   Create_Rectangles: Size=(5um, 8um), Offset=(1um, 1um),
                      Space=(3um), Layer=&bulk, LayerR=&tmp11;
   Size: layer=METAL1, value=3, layerR=&tmp12;
   Select: relation=OVERLAP, options=(NOT),
           layer1=&tmp11, layer2=&tmp12, layerR=METAL1_Dummy;

The first command creates rectangles in the whole area of the layout, with specified dimension, space, and offset. The next command resizes the METAL1 by the minimum spacing of METAL1, to keep enough clearance between the already-existing METAL1 wires and the newly-created dummy patterns. And, the final command removes the created rectangles overlapping with the already-existing METAL1 wires, and the rest of them becomes the dummy metal patterns.

This kind of operations will be done for all the METAL layers.

The actual operation steps to check the command behaviors are as follows:

1) Start Expert .

2) Run File->Open , load the project file guardian_example_27.eld , and then open the top cell. It contains some METAL1 wires and VIA rectangles.

3) Run Verification->DRC->DRC Script Panel , and then File-> Open in the script panel to load the sample DRC rule file guardian_example_27.dsf.

4) Run the loaded DRC script by DRC->Run in the DRC script panel . As a result, a dummy metal pattern will be created in the whole area of the layout design.

5) Set all the layers invisible except for the METAL1 and METAL1_Dummy, in order to observe the created dummy metals that are not overlapping with the original METAL1 objects, see Figure 1 .

To learn more about Guardian DRC, the different commands and their syntax as well as the different setup options, see the Guardian DRC user manual "guardian_users1.pdf" located in lib/expert/4.14.0.R/docs/ in your installation area.

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