Historically, there were two types of semi-custom devices:
In standard cell designs, cells from the library can freely be placed anywhere on the silicon and the number of IO pads and the size of the die can be freely chosen. Clearly this requires that all of the masks used for a chip are unique to that design and cannot be used again. Mask making is one of the largest costs in chip design. »(When) Will FPGAs Kill ASICs?
|5: (C) 2008-13, DJ Greaves, University of Cambridge, Computer Laboratory.|