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Automated DRC Scrubbing for DFM

IP.com Disclosure Number: IPCOM000211220D
Publication Date: 2011-Sep-28
Document File: 2 page(s) / 30K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to obtain 100% clean results when scrubbing for Design For Manufacturability (DFM). The method has MASH optimize the design for DFM, then run design rule checking (DRC). The DRC error markers are imported back into the design, and all MASH-inserted shapes that touch a design rule error marker are removed from the layout.

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Automated DRC Scrubbing for DFM

Design For Manufacturability (DFM) optimization requires making "post-design" updates to the layout. Examples of DFM optimizations include adding redundant vias, increasing the size of small metal islands, and removing "short edges" (very small jogs in metal lines).

Since the DFM optimization is done after the design is essentially complete, it is very important that the changes made to the design be "correct by construction." In deep submicron technologies, the ground rules are typically very complex. For example, basic width and spacing is no longer sufficient. There are "width dependent spacings", where the spacing between two lines depends upon the width of the lines. There are "joint rules", where the spacing between two shapes depends upon whether there either of the two lines has a "T" shape, with a wire extending away from the area separating them. There are "conditional enclosure" rules, where the amount of overlap required for a via in one direction depends upon the amount of overlap that exists in the other direction (for example, horizontal overlap depends upon how much vertical overlap is present.) In general, a 100% full understanding of these rules would require an optimization engine that is capable of optimizing two dimensions simultaneously, such as a full 2-D compaction engine. 2-D compaction is known to be NP-hard (intractable) due to the "visibility" problem - two edges may not have a projecting relationship (i.e., edge 1 and edge 2 have no overlapping coordinates), but as they move, such a relationship may be created.

A constraint-based optimization engine (MASH) is capable of doing a very good job of handling these complex 2-D rules, through a technique referred to as 1.5-D compaction. The MASH engine looks at corner-to-corner rela...