Floorplan (microelectronics)

Source: Wikipedia, the free encyclopedia.

Mock floorplan in an IC layout editor window

In

placement
of its major functional blocks.

In modern electronic design process floorplans are created during the floorplanning design stage, an early stage in the hierarchical approach to integrated circuit design.

Depending on the design methodology being followed, the actual definition of a floorplan may differ.

Floorplanning

Floorplanning takes in some of the geometrical constraints in a design. Here are some examples:

Mathematical models and optimization problems

In some approaches the floorplan may be a partition of the whole chip area into

axis aligned rectangles to be occupied by IC blocks. This partition is subject to various constraints and requirements of optimization: block area, aspect ratios
, estimated total measure of interconnects, etc.

Finding good floorplans has been a research area in

NP-hard
, i.e., require vast computational resources. Therefore, the most common approach is to use various optimization heuristics for finding good solutions.

Another approach is to restrict design methodology to certain classes of floorplans, such as sliceable floorplans.

Sliceable floorplans

A sliceable floorplan, with a slicing order indicated
The simplest non-sliceable floorplan

A sliceable floorplan is a floorplan that may be defined recursively as described below. [1]

  • A floorplan that consists of a single rectangular block is sliceable.
  • If a block from a sliceable floorplan is cut ("sliced") in two by a vertical or horizontal line, the resulting floorplan is sliceable.

Sliceable floorplans have been used in a number of early

polynomial time algorithms when restricted to sliceable floorplans.[2]

Further reading

  • The Chip Planner of the PLAYOUT System
  • VLSI Physical Design: From Graph Partitioning to Timing Closure, by Kahng, Lienig, Markov and Hu, , 2022
  • Fundamentals of Layout Design for Electronic Circuits, by Lienig, Scheible, Springer, , 2020

References

  1. ^
  2. ^ Sarrafzadeh, M, "Transforming an arbitrary floorplan into a sliceable one", Proc. 1993 IEEE/ACM International Conference on Computer-Aided Design (ICCAD-93), pp. 386-389.