Method to increase tensile stress of silicon nitride films using a post pecvd deposition uv cure

Abstract

High tensile stress in a deposited layer, such as a silicon nitride layer, may be achieved utilizing one or more techniques employed either alone or in combination. In one embodiment, a silicon nitride film having high tensile stress may be formed by depositing the silicon nitride film in the presence of a porogen. The deposited silicon nitride film may be exposed to at least one treatment selected from a plasma or ultraviolet radiation to liberate the porogen. The silicon nitride film may be densified such that a pore resulting from liberation of the porogen is reduced in size, and Si—N bonds in the silicon nitride film are strained to impart a tensile stress in the silicon nitride film. In another embodiment, tensile stress in a silicon nitride film may be enhanced by depositing a silicon nitride film in the presence of a nitrogen-containing plasma at a temperature of less than about 400° C., and exposing the deposited silicon nitride film to ultraviolet radiation.