FORMATION OF GATE STACK OF INTEGRATED CIRCUIT

摘要

PURPOSE: To provide a method for forming an integrated circuit whose gate stack structure has a reduced height. CONSTITUTION: A mask layer made of silicon dioxide is removed to leave only a metal layer and a polysilicon layer 30 on a final gate stack 32. It is because the polysilicon layer 30 is used for protecting a field oxide layer from an etchant for selectively removing a hard mask made of oxide that the hard mask made of oxide used for patterning the metal layer can be removed. A polysilicon layer 30 is etched to a gate oxide 12 by using a patterned metal layer 28 as a mask, but the field oxide layer 14 is not thinned.