For forming a dual damascene opening within a dielectric material, a via mask material and a trench mask material are formed over the dielectric material. A trench opening is formed through the trench mask material, and a via opening is formed through a via mask patterning material disposed over the via and trench mask materials. The via and trench mask materials exposed through the via opening of the via mask patterning material are etched away, and the via mask patterning material is etched away. A portion of the dielectric material exposed through the via opening is etched down to the underlying interconnect structure, and a portion of the dielectric material exposed through the trench opening is etched, to form the dual damascene opening.
