A VLSI floorplanner based on `balloon´ expansion

A novel floorplanning method is presented that models blocks as rectangular `balloons´, which are gradually expanded to determine their shapes and placement. Unlike the existing approaches, which assume the floorplan to be a slicing structure or which never handle fixed-shaped blocks, this method can handle fixed-shaped blocks as well as variable-shaped blocks on a general (non-slicing) layout structure. Experimental results show that the proposed method works effectively and gives an accurate estimate of chip area with only 3 to 6 percent difference from final layout, especially when the fixed- and variable-shaped blocks are mixed