INTEGRATION SCHEME FOR EXTENSION OF VIA OPENING DEPTH

摘要

An interconnect structure having an incomplete via opening is processed to deepen a via opening and to expose a metal line. In case the interconnect structure comprises a metal pad or a blanket metal layer, the metal pad or the metal layer is removed selective to an underlying dielectric layer to expose the incomplete via opening. Another dielectric layer is formed within the incomplete via opening to compensated for differences in the total dielectric thickness above the metal line relative to an optimal dielectric stack. A photoresist is applied thereupon and patterned. An anisotropic etch process for formation of a normal via opening may be employed with no or minimal modification to form a proper via opening and to expose the metal line. A metal pad is formed upon the metal line so that electrical contact is provided between the metal pad and the metal line.