(54) METHOD AND SYSTEM FOR
HIERARCHICAL METAL-END, ENCLOSURE
AND EXPOSURE CHECKING
(75) Inventors: Muni B. S. Mohan, San Jose; Kevin E.
Moynihan, Los Altos, both of CA (US)
(73) Assignee: Cadence Design Systems, Inc., San
Jose, CA (US)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/609,459
(22) Filed: Jul. 3, 2000
(51) Int. CI.7 G06F 17/50
(52) U.S. C I 716/5
(58) Field of Search 716/1, 2, 4, 5
(56) References Cited
U.S. PATENT DOCUMENTS
5,581,475 A * 12/1996 Majors 364/491
5,812,415 A * 9/1998 Baisuck 364/490
6,275,971 Bl * 8/2001 Levy et al 716/5
Pleskacz et al., "A DRC-Based Algorithm for Extraction of Critical Areas for Opens in Large VLSI Circuits," IEEE Trans, on CAD of ICs and Systems, vol. 18, No. 2, Feb. 1999, pp. 151-162.*
Jeppson et al., "Formal Definitions of Edge-Based Geometric Design Rules," IEEE Trans, on CAD of ICs and Systems, vol. 12, No. 1, Jan. 1993, pp. 59-69.*
An automated design rule checking software system processes a physical layout file of a circuit design to derive a list of vias needing design rule checks for violations in metal end, enclosure and/or exposure design rules. The process involves selection of vias likely to cause design rule check problems, selection of vias that violate an enclosure design rule, selection of vias violate metal end design rules, and design rule checks on the selected vias. Potentially problematic vias may be identified by expanding the dimensions of existing vias by a first predetermined minimum distance, subtracting out the metal area, and identifying those vias with residual portions remaining as potentially problematic vias. Candidate vias for an enclosure design rule check may be identified by expanding the dimensions of potentially problematic vias by a second predetermined minimum distance, subtracting out the metal area, and identifying those vias with residual portions remaining as violating the enclosure design rules. Candidate vias for a metal end design rule check may be identified by expanding the dimensions (excluding the corner regions) of potentially problematic vias by the first predetermined minimum distance, substracting out the metal area, and identifying those vias with residual portions remaining as violating the metal end design rules.
21 Claims, 10 Drawing Sheets