Three-dimensional phase change memory array including discrete middle electrodes and methods of making the same

A method of forming a three-dimensional phase change memory device, comprising:

• forming a vertically alternating sequence of continuous insulating layers and continuous sacrificial material layers over a substrate;
• forming line trenches laterally extending along a first horizontal direction through the vertically alternating sequence, wherein patterned portions of the vertically alternating sequence comprise alternating stacks of insulating strips and sacrificial material strips that laterally extend along the first horizontal direction and are laterally spaced apart along a second horizontal direction;
• forming a laterally alternating sequence of pillar cavities and sacrificial pillar structures within each of the line trenches;
• forming a phase change memory cell including a discrete metal portion, a phase change memory material portion, and a selector material portion at each level of the sacrificial material strips at a periphery of each of the pillar cavities;
• forming vertical bit lines in the two-dimensional array of pillar cavities;
• forming backside openings by removing the sacrificial pillar structures selective to the vertical bit lines;
• and
• replacing remaining portions of the sacrificial material strips with material portions that include electrically conductive strips.