Patent ID: 7060605

Claim:
A method for making a dielectric structure for dual-damascene applications, the method comprising: (a) providing a substrate; (b) fabricating first metallization lines in the substrate; (c) forming a barrier layer over the first metallization lines and the substrate; and (d) forming an inter-metal dielectric structure, the forming of the inter-metal dielectric structure, consisting the sequential steps of: (d)(i) forming an inorganic dielectric layer to define a via dielectric layer directly over the barrier layer, the inorganic dielectric layer being highly selective relative to the barrier layer when etched; (d)(ii) forming a carbon doped oxide layer to define a trench dielectric layer that is defined directly over and in direct contact with the inorganic dielectric layer, the trench layer being formed to define a metallization line layer of the inter-metal dielectric structure; (d)(iii) forming a trench in the carbon doped oxide layer using a first etch chemistry to etch the carbon doped oxide layer; and (d)(iv) forming a via in the inorganic dielectric layer from within the trench using a second etch chemistry to etch the inorganic dielectric layer, the second etch chemistry being different than the first etch chemistry.