Structure and fabrication of PCM-based capacitor bank

A semiconductor fabrication method for forming a capacitor and switch in parallel, the method comprising:

• forming a first metal layer over a first insulating layer that overlays a substrate;
• forming a thermal boundary resistance (TBR) layer over the first metal layer using insulator material that conducts heat;
• forming first, second, third, and fourth metal stacks by patterning and etching the TBR layer and the first metal layer;
• forming a second insulating layer on sides of the first, second, third, and fourth metal stacks;
• removing the TBR layer from the first, second, and fourth metal stacks;
• forming a patterned phase change material (PCM) layer that extends over:
• the second, third, and fourth metal stacks, second insulating layer material between the second and third metal stacks, and second insulating layer material between the third and fourth metal stacks;
• forming a dielectric layer over the substrate;
• forming a second metal layer over the dielectric layer;
• and
• patterning the second metal layer to form a capacitor electrode that extends over the first metal stack;
• wherein the capacitor is formed by the first metal stack, the dielectric layer over the first metal stack, and the capacitor electrode;
• and
• wherein the switch is formed by the second, third, and fourth metal stacks, the TBR layer, and the patterned PCM layer.

A method comprising:

• depositing first metal material over a first insulating layer that overlays a substrate;
• depositing thermal boundary resistance (TBR) material over the first metal material;
• patterning the first metal material and the TBR material to provide a first stack for a capacitor and to provide a second stack for a phase change material (PCM) switch;
• depositing an insulating layer between the first stack and the second stack;
• forming a PCM layer over the second stack;
• depositing second metal material over the first stack, the insulating layer, and the PCM layer;
• and
• patterning the second metal material to provide a first pad and a second pad.