Semiconductor structure and formation method thereof

Abstract

A semiconductor structure and a formation method thereof are provided. One form of the formation method includes: providing a substrate; forming a plurality of discrete mandrel layers on the substrate, wherein a minimum pitch between mandrel layers of the plurality of mandrel layers is a second pitch, and a minimum pitch between each of other pitches is a first pitch; forming second side wall covering layer between the mandrel layers having the second pitch; removing a first side wall covering layer, and maintaining the second side wall covering layer; forming a third side wall covering layer on an exposed side wall of the mandrel layer; removing the mandrel layer and the second side wall covering layer; and etching the substrate by using the third side wall covering layer as a mask to form a desired pattern. In embodiments and implementations of the present disclosure, the mandrel layer and the second side wall covering layer are configured to define a pitch between the third side wall covering layers. An extension direction perpendicular to the side wall of the mandrel layer is a lateral direction. The pitch between the third side wall covering layers can be adjusted by changing lateral dimensions of the mandrel layer and the second side wall covering layer according to process requirements. Therefore, diversified desired patterns having non-uniform pitches are formed more easily, and further, the flexibility and the general applicability of the semiconductor structure are improved favorably.

Dependencies are inferred from the claim text.