Capacitor structure and method for fabricating the same

A method for fabricating a capacitor structure with crown capacitors, comprising:

• providing a substrate having an array of conductive landing pads;
• forming a first dielectric layer on the substrate;
• forming a plurality of trenches in the first dielectric layer to expose the conductive landing pads, each of the trenches aligned over one of the conductive landing pads;
• conformally forming a bottom electrode layer on the first dielectric layer;
• conformally forming a first capacitor dielectric layer on the bottom electrode layer;
• forming a first top electrode layer on the first capacitor dielectric layer so that the first capacitor dielectric layer is interposed between the first top electrode layer and the bottom electrode layer;
• performing a first chemical mechanical polish process until the first dielectric layer, the bottom electrode layer, the first capacitor dielectric layer and the first top electrode layer are coplanar, whereby an array of inner capacitor predecessors are provided and each of the inner capacitor predecessors is aligned over one of the conductive landing pads, and each of the inner capacitor predecessors comprises the bottom electrode layer, the first top electrode layer and the first capacitor dielectric layer interposed between the bottom electrode layer and the first top electrode layer;
• removing a portion of the bottom electrode layer to form an array of bottom electrodes and an array of recesses aligned over the bottom electrodes;
• forming a cap dielectric layer to fill the recesses;
• performing a second chemical mechanical polish process until the first dielectric layer, the cap dielectric layer, the first capacitor dielectric layer and the first top electrode layer are coplanar, whereby an array of inner capacitors are provided, each of the inner capacitors having the cap dielectric on one end of the bottom electrode opposing the conductive landing pad;
• removing the first dielectric layer so that the inner capacitors are freestanding on the substrate;
• conformally forming a second capacitor dielectric layer on the inner capacitors;
• forming a second top electrode layer on the second capacitor dielectric layer so that the second capacitor dielectric layer is interposed between the second top electrode layer and the bottom electrode;
• and
• performing a third chemical mechanical polish process until the first top electrode layer, the second top electrode layer, the cap dielectric, the first capacitor dielectric layer and the second capacitor dielectric layer are coplanar so as to form an array of outer capacitors, whereby an array of crown capacitors is provided, each of the crown capacitors comprises one of the outer capacitors around one of the inner capacitors.

A method for fabricating a capacitor structure with crown capacitors, comprising:

• providing a substrate having an array of conductive landing pads;
• forming a first dielectric layer on the substrate;
• forming a plurality of trenches in the first dielectric layer to expose the conductive landing pads, each of the trenches aligned over one of the conductive landing pads;
• conformally forming a bottom electrode layer on the first dielectric layer;
• conformally forming a first capacitor dielectric layer on the bottom electrode layer;
• forming a first top electrode layer on the first capacitor dielectric layer so that the first capacitor dielectric layer is interposed between the first top electrode layer and the bottom electrode layer;
• performing a first chemical mechanical polish process until the first dielectric layer, the bottom electrode layer, the first capacitor dielectric layer and the first top electrode layer are coplanar, whereby an array of inner capacitor predecessors are provided and each of the inner capacitor predecessors is aligned over one of the conductive landing pads, and each of the inner capacitor predecessors comprises the bottom electrode layer, the first top electrode layer and the first capacitor dielectric layer interposed between the bottom electrode layer and the first top electrode layer;
• removing the first dielectric layer so that the inner capacitor predecessors are freestanding on the substrate;
• conformally forming a second capacitor dielectric layer on the inner capacitor predecessors;
• forming a second top electrode layer on the second capacitor dielectric layer;
• performing a second chemical mechanical polish process until the first top electrode layer, the second top electrode layer, the first capacitor dielectric layer, the second capacitor dielectric layer and the bottom electrode layer are coplanar;
• removing a portion of the bottom electrode layer to form an array of bottom electrodes and an array of recesses aligned over the bottom electrodes;
• forming a cap dielectric layer to fill the recesses;
• and
• performing a third chemical mechanical process until the first top electrode layer, the second top electrode layer, the first capacitor dielectric layer, the second capacitor dielectric layer and the cap dielectric layer are coplanar so that an array of crown capacitors are provided, each of the crown capacitors comprises an outer capacitor around one of an inner capacitor, the outer capacitor has the second capacitor dielectric layer interposed between the second top electrode layer and the bottom electrode, the inner capacitor has the first capacitor dielectric layer interposed between the first top electrode layer and the bottom electrode, and the cap dielectric layer is provided at one end of the bottom electrode opposing the conductive landing pad.