TSV without zero alignment marks

A method of forming a device comprising:

• providing a substrate;
• forming a dielectric layer disposed on the substrate, the dielectric layer comprises an upper and lower level;
• patterning the upper level of the dielectric layer to form at least first and second trench openings and alignment mark openings, wherein one of the first and second trench openings serves as a through via (TV) trench;
• forming an anti-reflective coating (ARC) layer on the substrate, wherein the ARC layer fills the at least first and second trench openings and alignment mark openings;
• forming a TV opening aligned to the TV trench, wherein the TV opening extends through the ARC layer and partially into the substrate;
• removing the ARC layer to expose the trenches and the openings;
• and
• forming a conductive layer over the substrate to fill the trenches and the openings.

A device comprising:

• a substrate, wherein the substrate comprises a surface which is devoid of zero alignment marks;
• a dielectric layer disposed on the substrate, the dielectric layer serves as an intermetal dielectric (IMD) layer which comprises an upper and lower portion, wherein the upper portion of the dielectric layer corresponds to a first metal level and the lower portion of the dielectric layer corresponds to a premetal dielectric (PMD) level, wherein
• the upper portion of the dielectric layer which corresponds to the first metal level comprises first and second trench openings and alignment mark openings, wherein one of the first and second trench openings serves as a through via (TV) trench,
• the PMD level separates the first and second trench openings and alignment mark openings in the first metal level from the substrate, and
• a TV opening aligned to the TV trench, wherein the TV opening extends through the PMD level and partially into the substrate;
• and
• a conductive layer fills the trenches and the openings.