Abstract: The present invention discloses a method and an apparatus for making digital integrated circuits by considering ramp delay and clock skew as constraints while minimizing the number of inserted buffers and overall wire length connecting components for large clock trees. The invention includes developing a set of circuit specifications including maximum clock skew, minimum driveability, and maximum ramp delay. These specifications are described in a hardware description language on a digital computer system, and a netlist is synthesized from this hardware description. A modified netlist is then formed by analyzing the netlist and inserting buffers into it to satisfy the circuit specifications of skew, driveability, and ramp delay. Thereafter, a digital integrated circuit is produced as specified by the modified netlist.

Abstract: The present invention discloses a method and an apparatus for making digital integrated circuits by considering ramp delay and clock skew as constraints while minimizing the number of inserted buffers and overall wire length connecting components for large clock trees. The invention includes developing a set of circuit specifications including maximum clock skew, minimum driveability, and maximum ramp delay. These specifications are described in a hardware description language on a digital computer system, and a netlist is synthesized from this hardware description. A modified netlist is then formed by analyzing the netlist and inserting buffers into it to satisfy the circuit specifications of skew, driveabilility, and ramp delay. Thereafter, a digital integrated circuit is produced as specified by the modified netlist.

Abstract: A floor-plan of component blocks of logical circuits, including the symbolic routing of major connection networks, is produced as part of the process for laying out an integrated circuit on a chip. The floor-plan is produced before performing optimized placement and routing of logical circuits within component blocks of the VLSI circuit. First, the logical circuits are apportioned into component blocks. Then, an initial lay out of the component blocks of the VLSI circuit is performed. The major connection networks are routed between the component blocks so that the major connection networks are connected to connection areas within the component blocks. The initial lay out of component blocks is adjusted as necessary in order to take into account the addition of the major connection networks. Once any needed adjustments are made, routing guidance information is generated as part of the floor plan. The routing guidance information indicates locations and sizes of the major connection networks.

Abstract: In a method for placement of components for a VLSI circuit, an initial number of current placements are selected. A greedy optimization is partially performed on each of the current placements. Then, a subset of the current placements which have been partially optimized is selected to be the new current placements. This selection is based on a global cost metric for the current placements. The global cost metric is, for example, based on the total length of all connection line networks for the circuit. The partial optimization and selection are repeated until there is only one current placement. Then, an optimization is performed on the remaining placement to obtain an optimized placement. The optimization is, for example, a completion of the partially performed greedy optimization.

Abstract: A system and method for routing interconnections through the layout of an integrated circuit is used in conjunction with a sliceable circuit layout specification that specifies the regions of the layout occupied by circuit components, a specification of the locations of terminals in the layout, and a netlist specifying for each terminal the set of other terminals that are to be connected to it. The regions of the circuit layout not occupied by circuit components are called routing regions. The circuit layout is sequentially sliced, defining a series of rectangular channels, each of which divides a region of the circuit layout containing two or more circuit components into two circuit regions each having at least one circuit component. For each channel, if there are one or more neighboring indented routing regions, a special channel is defined for each such indentation.