Method for forming T-shaped gate structure

Abstract

A method for forming a T-shaped gate is provided. The method includes providing a substrate. Then, a photoresist structure is formed over the substrate. The photoresist structure includes two development rates. Next, a mask with an opening is formed over the photoresist structure to pattern the photoresist structure. An angle exposure is applied to the photoresist structure, and the exposed photoresist structure is developed to form a T-shaped notch. A width of the T-shaped notch is gradually reduced from a top portion thereof to a bottom portion to expose a surface of the substrate. Then, a gate metal is deposited in the T-shaped notch. Thereafter, the patterned photoresist structure is removed to form the T-shaped gate.