METHOD FOR MANUFACTURING DUMMY GATE IN GATE LAST PROCESS AND DUMMY GATE IN GATE LAST PROCESS

摘要

Provided are a method for manufacturing a dummy gate in a gate last process and a dummy gate in a gate last process. The method comprises: providing a semiconductor substrate (20); growing a gate oxide layer (22) on the semiconductor substrate (20); depositing a bottom-layer amorphous silicon (24) on the gate oxide layer (22); depositing an oxide film/nitride film/oxide film (ONO) structure hard mask (26) on the bottom-layer amorphous silicon (24); depositing a top-layer amorphous silicon (28) on the ONO structure hard mask (26); depositing a hard mask layer (30) on the top-layer amorphous silicon (28); forming a photoresist line (32) on the hard mask layer (30), and miniaturizing the formed photoresist line (32), so that the width of the miniaturized photoresist line is smaller than and equal to 22 nm; and etching the hard mask layer (30), the top-layer amorphous silicon (28), the ONO structure hard mask (26) and the bottom-layer amorphous silicon (24) by using the photoresist line (32) as a standard, and removing the photoresist line (32), the hard mask layer (30) and the top-layer amorphous silicon (28). Therefore, the critical size and sectional profile of the gate can be precisely controlled, the roughness of the gate line can be effectively improved, and the performance and stability of the device can be ensured.