Physical Design Rule

What's Physical Design Rule

1. Interface between the circuit designer and process engineer
2. Guidelines for constructing process masks
3. Unit dimension: minimum line width

scalable design rules: lambda parameter
absolute dimensions: micron rules

4. Rules constructed to ensure that design works even when small fab errors (within some tolerance) occur
5. A complete set includes

set of layers
intra-layer: relations between objects in the same layer
inter-layer: relations between objects on different layers

Why Physical Design Rule:

To be able to tolerate some level of fabrication errors such as

1. Mask misalignment
2. Dust
3. Process parameters (e.g., lateral diffusion)
4. Rough surfaces

Basic Physical Design Rule:

1. Width (INTERNAL)
2. Spacing (EXTERNAL)
3. Overlap (ENCLOSE)
4. Extension (ENCLOSE)
5. Clearance (EXTERNAL, ENCLOSE)

For Logic Design Rule, please refer to http://vlsi-concept.blogspot.com/2009/01/design-rule-checking-drc.html