SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE AND ITS MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To provide a semiconductor integrated circuit device which realizes reduction in a manufacturing cost by cutting the number of photomasks, and its manufacturing method. SOLUTION: An SIMOX substrate is used, wherein an oxide film 8 is formed in a substrate 9 and an n- layer 2 is formed thereon. In the n- layer 2, an n-channel MOSFET (NMOS) and a p-channel MOSFET (PMOS) of a CMOS cell 1 are formed isolated and independent via an isolation groove, respectively. A p-well region 3 and an n+ source region 4 are formed to self-align using a gate electrode 12 as a mask. By using the isolation groove, it is possible to eliminate the need for an LOCOS oxide film and a stopper region, and to greatly cut the number of photomasks necessary in a manufacturing process by the application of the isolation groove formation and self alignment.