Semiconductor devices including capacitors and methods of manufacturing the same
A semiconductor device includes a first capacitor structure, a second capacitor structure, and an insulation pattern. The first capacitor structure includes a first lower electrode, a first dielectric layer and a first upper electrode sequentially stacked on a substrate. The second capacitor structure includes a second lower electrode, a second dielectric layer and a second upper electrode sequentially stacked on the substrate, and is adjacent to the first capacitor structure. The insulation pattern partially fills a space between the first and second capacitor structures, and an air gap is formed between the first and second capacitor structures on the insulation pattern.
1. A method of manufacturing a semiconductor device, comprising:
forming a mold layer on a substrate, the mold layer having first and second holes;
forming a first capacitor structure in the first holes, the first capacitor structure including a first lower electrode, a first dielectric layer and a first upper electrode;
forming a second capacitor structure in the second holes, the second capacitor structure including a second lower electrode, a second dielectric layer and a second upper electrode;
partially etching the mold layer between the first and second capacitor structures to form an insulation pattern; and
forming a plate electrode on the first and second upper electrodes to overlie the insulation pattern, an air gap being formed by the plate electrode between the first and second capacitor structures.
2. The method of claim 1 , wherein forming the first and second capacitor structures includes:
forming a lower electrode layer on inner walls of the first and second holes and the mold layer;
partially etching the lower electrode layer to form the first and second lower electrodes having a cylindrical shape;
forming a dielectric layer on the first and second lower electrodes and the mold layer;
forming an upper electrode on the dielectric layer to fill remaining portions of the first and second holes; and
planarizing upper portions of the upper electrode layer and the dielectric layer to form the first upper electrode and the first dielectric layer in the first holes and to form the second upper electrode and the second dielectric layer in the second holes.
3. The method of claim 1 , wherein partially etching the mold layer includes a dry etch process or a wet etch process.
4. The method of claim 1 , prior to partially etching the mold layer, further comprising forming a mask covering a portion of the mold layer in which any of the first and second capacitor structures is formed.
5. The method of claim 1 , wherein the insulation pattern is formed to have a thickness of about 60% to about 80% of a height of the first and second capacitor structures.
6. The method of claim 1 , wherein an inner diameter of each of the first and second holes is greater than a distance between the first and second holes.
7. The method of claim 1 , wherein forming the mold layer includes:
forming a mold layer using an insulating material having a dielectric constant lower than silicon nitride; and
partially etching the mold layer to form the first and second holes.
8. The method of claim 7 , wherein the mold layer includes a first silicon oxide layer, an etch stop layer and a second silicon oxide layer, and the first silicon oxide layer is formed to have a top surface substantially coplanar with a top surface of the insulation pattern.
9. The method of claim 1 , wherein forming the plate electrode includes:
forming a first plate electrode layer on the first and second upper electrodes under a deposition condition in which the first plate electrode only partially fills a space between the first and second upper electrodes; and
forming a second plate electrode layer on the first plate electrode layer under a second deposition condition having a step coverage better than the first deposition condition.
10. The method of claim 9 , wherein the first and second plate electrode layers are formed using substantially the same material.