A method for manufacturing an interconnect structure includes providing a metal interconnect layer, forming a dielectric layer (202) on the metal interconnect layer, forming a fluorocarbon layer (301) on the dielectric layer, forming a patterned hardmask layer on the fluorocarbon layer, etching the fluorocarbon layer and the dielectric layer using the patterned hardmask layer as a mask to form a trench in the dielectric layer and a through-hole through the dielectric layer to the metal interconnect layer, forming a metal layer filling the trench and the through-hole, and planarizing the metal layer until the planarized metal layer (801) has an upper surface that is flush with an upper surface of the fluorocarbon layer. The interconnect structure thus formed has an improved reliability.