Method for manufacturing semiconductor device

Abstract

A method for manufacturing a semiconductor device includes forming contacts disposed in a dielectric layer. The method of forming the contacts includes forming contact holes and then filling with a conductive material. The method of forming the contact holes includes steps of forming openings in the dielectric layer to expose active regions, introducing a first oxygen plasma and a first fluorine plasma to remove by-products and oxidize inner surfaces of the openings, introducing a second oxygen plasma and a second fluorine plasma to remove the oxidized inner surfaces and repair the active regions, introducing a third oxygen plasma to oxidize inner surfaces again to form an oxide layer, and removing the oxide layer. The cross-sectional structure of two adjacent contact holes includes a capital, a base, and a shaft between the capital and the base, wherein the shaft has a smaller width than the base and the capital.