Connectivity Options for DRC Spacing Check Operations in Savage

Introduction

An IC layout has to satisfy many technological design requirements. One of these is spacing, i.e., a layout object has to be separated from another one by some minimal distance.

In addition, any spacing requirement (e.g. minimal distance between layout objects) varies depending on the particular features of the layout objects, e.g. the layer the objects belong to, the purpose of these objects, etc.

A rule set (or script) of DRC commands allows a designer to separate objects with particular features and then to check them according to technological requirements.

An important characteristic of a layout object is that it belongs to an electrical node as almost every geometrical object is a part of an electrical circuit, e.g. a wire, a drain, a gate, etc. The technological requirements for objects can be different depending on whether these objects belong to the same electrical node.

The information that defines whether layout objects belong to the same electrical node is called “connectivity data”. This data can be used along with any spacing requirements during the rule checking.

If a designer is going to use DRC spacing check operations which take into account the connectivity information the option C or C’ must be specified. The option C in a DRC check operation means the operation checks a spacing requirement only between the objects that belong to different electrical nodes. The option C’ means the operation checks the spacing requirement only between objects that belong to the same electrical node.