in detail in the documentation provided by the semiconductor manufacturer. Academic design rules are often specified in terms of a scalable parameter, λ, so that all geometric tolerances in a design may be defined as integer multiples of λ. This simplifies the migration of existing chip layouts to newer processes. Industrial rules are more highly optimized, and only approximate uniform scaling. Design rule sets have become increasingly more complex with each subsequent generation of semiconductor process. Software The main objective of design rule checking (DRC) is to achieve a high overall yield and reliability for the design. If design rules are violated the design may not be functional. To meet this goal of improving die yields, DRC has evolved from simple measurement and Boolean checks, to more involved rules that modify existing features, insert new features, and check the entire design for process limitations such as layer density. A completed layout consists not only of the geometric representation of the design, but also data that provides support for the manufacture of the design. While design rule checks do not validate that the design will operate correctly, they are constructed to verify that the structure meets the process constraints for a given design type and process technology. DRC software usually takes as input a layout in the GDSII standard format and a list of rules specific to the semiconductor process chosen for fabrication. From these it produces a report of design rule violations that the designer may or may not choose to correct. Carefully "stretching" or waiving certain design rules is often used to increase performance and component density at the expense of yield. DRC products define rules in a language to describe the operations needed to be performed in DRC. For example, Mentor Graphics uses Standard Verification Rule Format (SVRF) language in their DRC rules files and Magma Design Automation is using Tcl-based language. A set of rules for a particular process is referred to as a run-set, rule deck, or just a deck. DRC is a very computationally intense task. Usually DRC checks will be run on each sub-section of the ASIC to minimize the number of errors that are detected at the top level. If run on a single CPU, customers may have to wait up to a week to get the result of a Design Rule check for modern designs. Most design companies require DRC to run