Metal-insulator-metal structure

A semiconductor device, comprising:

• a substrate;
• a dielectric layer over the substrate;
• and
• a metal-insulator-metal structure embedded in the dielectric layer, the metal-insulator-metal structure comprising:
• a bottom conductor plate layer comprising a first opening and a second opening,
• a first insulator layer over the bottom conductor plate layer,
• a middle conductor plate layer over the first insulator layer, the middle conductor plate layer comprising a third opening, a first dummy plate disposed within the third opening, and a fourth opening,
• a second insulator layer over the middle conductor plate layer,
• a top conductor plate layer over the second insulator layer, the top conductor plate layer comprising a fifth opening, a second dummy plate disposed within the fifth opening, a sixth opening, and a third dummy plate disposed within the sixth opening,
• wherein the first opening, the third opening, and the fifth opening are vertically aligned,
• wherein a first vertical projection area of the fifth opening is greater than a second vertical projection area of the third opening,
• wherein the second vertical projection area of the third opening is greater than a third vertical projection area of the first opening.

A semiconductor structure, comprising:

• a first contact feature, a second contact feature, and a third contact feature over a substrate;
• a dielectric layer over the first contact feature, the second contact feature and the third contact feature;
• a bottom conductor plate layer over the dielectric layer comprising a first opening and a second opening;
• a middle conductor plate layer over and insulated from the bottom conductor plate layer, the middle conductor plate layer comprising a third opening and a fourth opening;
• a top conductor plate layer over and insulated from the middle conductor plate layer, the top conductor plate layer comprising a fifth opening and a sixth opening;
• a first contact via extending through the first opening, the third opening, and the fifth opening to electrically couple to the first contact feature;
• a second contact via extending through the second opening and the sixth opening to electrically couple to the middle conductor plate layer and the second contact feature;
• and
• a third contact via extending through the fourth opening to electrically couple to the top conductor plate layer, the bottom conductor plate layer and the third contact feature,
• wherein the first contact via is electrically insulated from the bottom conductor plate layer, the middle conductor plate layer and the top conductor plate layer.