Gate array core cell for vlsi asic devices

Abstract

A very efficient gate array core cell in which the base core cell consists of a group of 6 PMOS transistors and a group of 6 NMOS transistors. It also includes pre-wiring of 2 of the 6 PMOS transistors, with 2 of the 6 NMOS transistors at polysilicon level or at local interconnect level while leaving the remaining PMOS and NMOS transistors as individual transistors to be interconnected during the functional ASIC metallization process. The core cell also has 2 polysilicon or local interconnect wires embedded in it, which can be used to interconnect transistors for logic function implementation. The core cell defined in this invention is highly flexible and has been analyzed to interconnect all types of logic and memory functions needed for ASIC designs. The layout of the transistors, pre-wiring of the strategic transistors at polysilicon level or at local interconnect level, and embedded polysilicon or local interconnect wires reduce the core cell size significantly. This core cell design reduces the overall wiring lengths, parasitic capacitance, which in turn reduce delays, power dissipation and increase ASIC performance and circuit density. Gate array ASIC components designed using this core cell provide circuit density, performance and power dissipation characteristics comparable to the Standard Cell ASICs but with the advantage of reducing the mask cost and processing time by about 50 percent.