Wen-Chuan Hsu

US Patent:

62021966, Mar 13, 2001

Filed:

Feb 3, 1998

Appl. No.:

9/017378

Inventors:

Tammy Huang - Fremont CA
Wen-Chuan Hsu - Los Altos CA

Assignee:

LSI Logic Corporation - Milpitas CA

International Classification:

G06F 1750

US Classification:

716 14

Abstract:

A method for optimizing routing mesh segment widths within limits imposed by voltage drop and metal migration requirements, beginning with an initial mesh comprising a plurality of horizontal segments forming rows and a plurality of vertical segments forming columns. First, a voltage drop and current density associated with each segment is determined. Then a first width for each segment is found by scaling each segment width using a voltage drop scaling factor so that the routing mesh has a maximum voltage drop that satisfies the voltage drop requirement. Next, widths for each segment are determined such that the metal migration requirement minus a margin is satisfied. Then the method ensures that each segment within each row, and each segment within each column, is not more than a first scaling factor wider than its neighboring segments. A second width for each segment is found by ensuring that each segment within each row is not more than a second scaling factor wider than segments at a same vertical position in neighboring rows, and each segment within each column is not more than the second scaling factor wider than segments at a same horizontal position in neighboring columns. The method then selects the larger of the first width and second width for each segment, determines the voltage drop and current density associated with each segment, and checks whether the voltage drop and metal migration requirements are violated.