Shuttle Mask Floorplanning

With the dramatic increase in mask production cost, it is difficult for small and medium-size enterprisers to do effective prototyping and low-volume manufacturing of IC designs. Multi Project Wafer(MPW) is an efficient method to share the mask cost between different projects. Designs from multiple customers can be put on one single mask substrate, called shuttle mask, to produce a MPW. We have studied this problem of shuttle mask floorplanning. Unlike traditional floorplanning, we need to consider the side-to-side wafer dicing constraint of the diamond sawing technology. We consider grid packing in this research as the side-to-side dicing constraint can be easily taken care of by cutting along the grid lines and no dies will be destroyed. We have defined a special type of grid, called modified &alpha-restricted grid, to reduce the size of the solution space. Besides, the &alpha-restricted grid structure is good for controlling the white space margin of the diced chips. Chips of the same design will have the same margin lying within a range given by the users. In the future, we will consider more information like the demands of different designs, the costs of wafer and mask, etc.