Semiconductor device containing bit lines separated by air gaps and methods for forming the same

A method of forming a semiconductor structure, comprising:

• forming a semiconductor device over substrate;
• forming bit lines over the semiconductor device;
• forming a bit-line-level sacrificial fill layer between the bit lines;
• forming a via-level dielectric material layer over the bit lines and the bit-line-level sacrificial fill layer;
• forming conductive via structures through the via-level dielectric material layer directly on a top surface of a respective one of the bit lines;
• forming openings through the via-level dielectric material layer such that surfaces of the bit-line-level sacrificial fill layer are physically exposed underneath the openings;
• and
• removing the bit-line-level sacrificial fill layer by introducing an etchant through the openings that removes the sacrificial fill material to form air gaps between the bit lines.