Self-aligned interconnects

A method of forming an interconnect structure, comprising the steps of:

• providing a first entity comprising:
• a first set of one or more line structures having a top surface, comprising:
• a first set of one or more conductive lines,
• a first set of one or more dielectric lines of width (w) made of a first dielectric material, aligned with and overlaying the first set of one or more conductive lines, and comprising the top surface,
• a second dielectric material of such a nature that the first dielectric material can be etched selectively with respect to the second dielectric material, the second dielectric material surrounding each line structure and having a top surface coplanar with the top surface of the one or more line structures;
• providing a patterned mask on the first entity, wherein the pattern comprises:
• at least one via exposing the whole width (w) of an underlying dielectric line of the first set of one or more dielectric lines, and/or
• at least one trench exposing the whole width (w) of at least one dielectric line of the first set of one or more dielectric lines;
• etching selectively the first dielectric material with respect to the second dielectric material through the patterned mask so as to form one or more vias in the first dielectric material, thereby exposing a portion of the set of one or more conductive lines;
• and
• removing the patterned mask, thereby uncovering a perforated surface.