Process for forming a borderless via in a semiconductor device

摘要

A method is used to form a borderless via in a semiconductor device. A conductive layer, a borophosphosilicate glass (BPSG) layer and a patterned first mask layer are formed on a dielectric layer in sequence. The BPSG layer is patterned into a BPSG plug while using the patterned first mask layer as a mask. A second mask layer is formed to cover the patterned first mask layer and the metal layer. The conductive layer is defined to form a conductive line beneath the BPSG plug and the second mask layer. The first and second photoresist mask layers are removed. An inter-metal dielectric layer is formed around the BPSG plug and the conductive line. A via is formed in the inter-metal dielectric layer by removing the BPSG plug. A barrier layer and a metal layer fill the via to form a metal plug.