Method of area compaction for integrated circuit layout design

A method of area compaction for integrated circuit layout design comprising:

• determining physical extent boundaries for each layer of at least first circuit and second circuit building blocks, wherein determining physical extent boundaries includes determining for each respective layer of the first circuit and second circuit building blocks (i) a used portion and (ii) a free portion, the used portion corresponding to a functional portion of the respective circuit building block and the free portion corresponding to a non-functional portion of the respective circuit building block;
• establishing packing keys with respect to the determined physical extent boundaries of each layer of the first circuit and second circuit building blocks, respectively, wherein the packing keys define an interlocking characteristic for packing compaction of the corresponding first circuit or second circuit building block with another circuit building block;
• determining packing compatibilities of one or more pairs of circuit building blocks of a library of circuit building blocks, wherein the packing compatibility for a given pair of circuit building blocks is determined according to respective packing keys of each circuit building block of the given pair of circuit building blocks;
• forming clusters between two or more of the first circuit building block, the second circuit building block, and another circuit building block of the library of circuit building blocks based upon respective packing compatibilities, wherein a cluster includes at least one pair of circuit building blocks interlocked with one another at an interlocking boundary;
• defining a packing optimization variable for the at least one pair of interlocked circuit building blocks of one or more clusters, wherein the packing optimization variable includes (i) a value of unity in response to the at least one pair of interlocked circuit building blocks of a given cluster having a packing compaction of one hundred percent (100%) at the interlocking boundary (ii) a value less than unity in response to the at least one pair of interlocked circuit building blocks having a packing compaction of less than one hundred percent (100%) at the interlocking boundary;
• storing the formed clusters in the library;
• selecting a cluster from among the formed clusters;
• determining whether an opportunity exists for optimizing a packing compaction of the selected cluster, wherein responsive to a determination that opportunity exists, then (a)(i) forming a new cluster using (a)(i)(1) at least one of the circuit building blocks of the selected cluster and (a)(i)(2) another circuit building block from the library or another cluster of the formed clusters and (a)(ii) repeating the determining step for the new cluster, otherwise (b) identifying the cluster as optimized, storing the optimized cluster in the library, proceeding with the selection of another cluster from among the formed clusters, and repeating the determining step until a desired percentage of clusters in the library have been optimized;
• placing and routing circuit building blocks and clusters in a 3-dimensional integrated circuit design;
• quantizing a block size for the 3-dimensional integrated circuit design that includes at least various circuit building blocks and optimized clusters;
• and
• adding tile regions among the various circuit building blocks and optimized clusters to fill in a difference between (i) an actual size of the various circuit building blocks and optimized clusters and (ii) the quantized block size, wherein the added tile regions are adapted to create regularity within the quantized 3-dimensional integrated circuit design.