Method of fabricating crown capacitor

A method of fabricating a crown capacitor, comprising:

• providing a substrate having a transistor, comprising at least one diffused region, formed thereon and overlaid by a first insulating layer;
• forming bit lines in the first insulating layer, wherein the first insulating layer isolates the bit lines and the substrate;
• forming a first silicon nitride layer over the first insulating layer;
• forming a second insulating layer over the first silicon nitride layer;
• patterning the second insulating layer, the first silicon nitride layer and the first insulating layer to form a contact hole which exposes the device areas;
• forming a second silicon nitride layer on the surface of the second insulating layer and conformally extending to the sidewalls and the bottom of the contact hole;
• etching back the second silicon nitride layer to form masking spacers on the sidewalls of the contact hole to prevent the bit lines from being damaged and shorting;
• removing the second insulating layer;
• conformally forming a first conductive layer over the first silicon nitride layer and extending to the surface of the masking spacers and the bottom of the contact hole;
• forming a third insulating layer over the first conductive layer, wherein the third insulating layer fills the contact hole;
• patterning the third insulating layer and the first conductive layer to the first silicon nitride layer leaving portions of the third insulating layer with vertical sidewalls over the contact hole;
• forming a second conductive layer over the third insulating layer and the first silicon nitride layer;
• etching back the second conductive layer to form conductive spacers on the sidewalls of the third insulating layer;
• removing the third insulating layer to expose the conductive spacers and the first conductive layer as a bottom electrode;
• forming a capacitor dielectric layer on the bottom electrode;
• and
• forming a top electrode over the capacitor dielectric layer.