METHOD FOR FORMING DUAL METAL GATE WITH DIFFERENT WORK FUNCTIONS TO MAKE NMOS AND PMOS GATE ELECTRODES HAVE DIFFERENT WORK FUNCTIONS

摘要

Purpose: a kind of method is used to form the double-metal grid with different work functions and is arranged to manufacture NMOS (n- NMOS N-channel MOS Ns), and PMOS gate electrodes have different work functions by using two kinds of metals, tantalum and ruthenium. Construction: a gate insulating layer (110) is formed in a silicon substrate (100), has the regions PMOS and the regions NMOS, is isolated by an insulation oxide layer. After photoresist is formed in gate insulating layer, to carry out opening the top of gate insulating layer using a patterning process of a PMOS gate masks. A metal layer (120) with a high work content is formed in open gate insulating layer and photoresist. By removing photoresist, the metal layer of the high work content formed on photoresist is eliminated by a lift-off method to form a PMOS gate patterns. After photoresist is formed in substrate, there is PMOS gate patterns, a NMOS gate patterns are made of metal (130) with a low work function by same procedure, use a NMOS gate masks.