Capacitor constructions
View Patent ↗A method of forming a capacitor includes, a) providing a node to which electrical connection to a first capacitor plate is to be made; b) then, providing a finned lower capacitor plate in ohmic electrical connection with the node using no more than one photomasking step; and c) providing a capacitor dielectric layer and a conductive second capacitor plate layer over the conductive layer. Such is preferably accomplished by, i) providing a layer of conductive material outwardly of the node; ii) providing a first masking layer over the conductive material layer; iii) etching a first opening into the first masking layer over the node; iv) providing a second masking layer over the first masking layer to a thickness which less than completely fills the first opening; v) anisotropically etching the second masking layer to define a spacer received laterally within the first opening and thereby defining a second opening relative to the first masking layer which is smaller than the first opening; vi) after said anisotropically etching, etching unmasked first masking layer material away; vii) after said anisotropically etching, etching through the conductive material layer to extend the second opening to the node, the node and conductive layer being electrically isolated from one another after the conductive material layer etching; viii) plugging the extended second opening with an electrically conductive plugging material, the plugging material electrically interconnecting the node and conductive layer. Novel capacitor constructions are also disclosed.
1. A capacitor construction comprising:
a conductive pillar having a lower surface in electrical connection with a diffusion region disposed between a pair of word lines, and having an upper surface that opposes and is wider than the lower surface;
a conductive plug in electrical connection with the upper surface of the conductive pillar, the conductive plug having a diameter that is less than the width of the upper surface of the conductive pillar; and
a plurality of pairs of laterally opposing fins, each pair of laterally opposing fins being interconnected with and projecting laterally from the conductive plug.
2. The capacitor construction of claim 1 wherein the plurality of pairs comprises at least three pairs.
3. The capacitor construction of claim 1 wherein each of the pairs of fins extends laterally beyond the width of the upper surface of the conductive pillar.
4. The capacitor construction of claim 1 wherein the plug and the fins comprise conductive polysilicon.
5. The capacitor construction of claim 1 further comprising a capacitor dielectric layer over the fins.
6. The capacitor construction of claim 5 further comprising a conductive capacitor plate layer over the capacitor dielectric layer.