Automated creation of power distribution grids for tiled cell arrays in integrated circuit designs
AssigneeHewlett-Packard Development Company, L.P.
InventorJeremy Glen Slade
Life of this patent
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Abstract
A VLSI circuit having regular, tiled arrays of cells is designed using a method and an apparatus to allow automatic creation of the artwork needed to distribute power from a top-level power grid (i.e., lines VDD and GND) to power rails in lower-level metal layers of cells. That is, the cell arrays may include power rails that need to be connected to a top-level power grid. The method and apparatus may be used in conjunction with software tools used to create other elements of the VLSI design. The method and apparatus automate the task of connecting each of the cells in the array to the power lines.
Claims19
A method for creating a power distribution grid for tiled cells in an integrated circuit, the cells each having a plurality of metal layers, the method, comprising:
- defining power rails on one or more of the metal layers for one or more of the cells, wherein a power rail is constrained to exist in designated resources;
- determining intersections of the resource shape between vertically adjacent metal layers;
- and
- stitching together the intersections to form power strap shapes, comprising:
- in each metal layer:
- determining names of neighboring intersections,
- determining original designated resources encompassing the neighboring intersections, and
- stitching the neighboring intersections together when the names and the original designated resources match.
A computer-readable medium comprising programming for automatic creation of a power grid in an integrated circuit cell array, the programming providing execution of the following steps:
- defining power rails on one or more of the metal layers for one or more of the cells, wherein a power rail is constrained to exist in designated resources;
- determining intersections of the resources shape between vertically adjacent metal layers;
- and
- stitching together the intersections to form power strap shapes, comprising:
- in each metal layer:
- determining names of neighboring intersections,
- determining original designated resources encompassing the neighboring intersections, and
- stitching the neighboring intersections together when the names and the original designated resources match.
A method for creating power grids in an integrated circuit, the integrated circuit comprising a plurality of tiled cells, the cells each comprising a plurality of metal layers, the method comprising:
- defining power rails on one or more of the metal layers for one or more of the cells, wherein a power rail is constrained to exist in designated resources, comprising:
- determining an x or a y reference point for power rails in a cell, and
- designating the power rails as one of ground and supply;
- determining intersections of the resources between vertically adjacent metal layers;
- and
- stitching together the intersections to form power strap shapes.
An apparatus for automated creation of power distribution grids in an integrated circuit, wherein the integrated circuit comprises a plurality of cells having a same footprint, each of the plurality of cells comprising a plurality of layers, the apparatus comprising:
- means for determining power rails in one or more of the plurality of layers;
- means for building intersections between the power rails and resources in the one or more of the plurality of layers;
- and
- means for building power strap shapes based on the intersections, wherein the means for building the power strap shapes comprises:
- means for determining intersection names of adjacent intersections,
- means for determining original designated resource shapes and encompassing the adjacent intersections, and
- means for stitching the adjacent intersections together when the intersection names and the original designated resources match.
Dependencies are inferred from the claim text.