Method of making integrated circuit capacitor including tapered plug

A method of making an integrated circuit capacitor comprising the steps of:

• forming a first dielectric layer adjacent a substrate;
• forming a metal plug comprising
• an upper portion extending toward an uppermost surface of the first dielectric layer, and
• a lower portion disposed in the first dielectric layer and having a tapered width which increases in a direction toward the substrate;
• forming a trench in the first dielectric layer around the upper portion of the metal plug;
• forming a second dielectric layer adjacent the metal plug;
• and
• forming an upper electrode layer on the second dielectric layer.

A method of making an integrated circuit capacitor comprising:

• forming a first dielectric layer adjacent a substrate;
• forming a metal plug having a tapered width which increases in a direction toward the substrate;
• forming a trench in the first dielectric layer to a depth greater than about half a thickness of the first dielectric layer;
• forming a second dielectric layer adjacent the metal plug;
• and
• forming an upper electrode layer on the second dielectric layer.