3d phase change memory and method of manufacturing the same

A method of manufacturing a 3D phase change memory, comprising:

• providing a substrate;
• forming a plurality of first layers and a plurality of second layers alternately stacked on the substrate to constitute a layer stack;
• performing a first photolithography process to form a trench in the layer stack, the trench extending from the substrate in a vertical direction perpendicular to the substrate and penetrating through the entire layer stack, and the trench extending in a horizontal second direction;
• performing an etching process to remove portions of the second layers exposed from the trench, such that each of the second layers is recessed from the trench in a horizontal first direction to form a lateral recess, wherein the first direction is orthogonal to the second direction;
• forming an adhesive layer on a surface of each of the lateral recesses;
• forming a top electrode on each of the adhesive layers, each of the top electrodes filling the respective lateral recess, wherein lateral surfaces of the adhesive layers and the top electrodes are flush with lateral surfaces of the first layers exposed from the trench, and together constitute two sidewalls of the trench that are opposite to each other in the first direction;
• sequentially forming ovonic threshold switch layers and phase change layers on the two sidewalls of the trench, respectively;
• forming a bottom electrode filling up the trench between the two phase change layers in the trench;
• and
• performing a second photolithography process to remove portions of the bottom electrode and portions of the two phase change layers to form a plurality of holes extending from the substrate in the vertical direction to a surface of the layer stack, and the holes are located in the trench and arranged along the second direction.