Method of fabricating a capacitor for a semiconductor device
View Patent ↗A capacitor for a semiconductor device includes a first inter metal dielectric layer is disposed on a substrate. A first electrode is disposed on the first inter metal dielectric layer. A second electrode partially overlaps the first electrode. A first dielectric layer is disposed between the first and second electrodes. A third electrode partially overlaps the second electrode. A second dielectric layer is disposed between the second and third electrodes. An etch stop layer is disposed on the first, second, and third electrodes. A second inter metal dielectric layer is formed on the etch stop layer and includes first, second, and third via holes exposing the first and third electrodes and the etch stop layer. First, second, and third plugs are disposed in the first, second, and third via holes.
1. A method for fabricating a capacitor for a semiconductor device, comprising the steps of:
forming a first inter metal dielectric layer on a substrate;
forming a first metal layer to fill a trench on the first inter metal dielectric layer;
polishing the first metal layer using a chemical mechanical polishing to form a first electrode;
forming a first dielectric layer, a second metal layer, a second dielectric layer, and a third metal layer on the first electrode;
patterning the third metal layer using a selective etching to form a third electrode;
patterning the second metal layer using a selective etching to form a second electrode that overlaps the first electrode and the third electrode;
forming an etch stop layer to cover the first, second, and third electrodes, said etch stop layer being in direct contact with at least the third electrode;
forming a second inter metal dielectric layer over the etch stop layer;
etching the second inter metal dielectric layer using a selective photolithography process to form via holes to expose the etch stop layer;
removing the etch stop layer to expose the first, second, and third electrodes;
filling the via holes to form plugs, the plugs electrically connecting the first, second, and third electrodes; and
forming metal wirings on the second inter metal dielectric layer to conduct electricity to the first to third electrodes through the plugs.
2. The method according to claim 1 , wherein the etch stop layer comprises a nitride material.
3. The method according to claim 1 , wherein both the inter metal dielectric layers comprise an oxide material.
4. The method according to claim 1 , wherein a thickness of second dielectric material remains after patterning the third metal layer.
5. The method according to claim 4 , wherein the thickness of the second dielectric material is about 100 Å.
6. The method according to claim 1 , wherein said etch stop layer has a high etch selectivity to the second inter metal dielectric layer.
7. A method for fabricating a capacitor for a semiconductor device, said method comprising the steps of:
forming a first inter metal dielectric layer on a substrate;
forming a first metal layer to fill a trench on the first inter metal dielectric layer;
polishing the first metal layer using a chemical mechanical polishing to form a first electrode;
forming a first dielectric layer, a second metal layer, a second dielectric layer, and a third metal layer on the first electrode;
patterning the third metal layer using a selective etching to form a third electrode;
patterning the second metal layer using a selective etching to form a second electrode that overlaps the first electrode and the third electrode;
forming an etch stop layer, said etch stop layer being in direct contact with the first, second and third electrodes;
forming a second inter metal dielectric layer over the etch stop layer;
etching the second inter metal dielectric layer to form via holes to expose the etch stop layer;
removing the etch stop layer to expose the first, second, and third electrodes at a first, second and third contact points respectively;
filling the via holes to form plugs, the plugs electrically connecting the first, second, and third electrodes; and
forming metal wirings on the second inter metal dielectric layer to conduct electricity to the first to third electrodes through the plugs, wherein
the second dielectric material covers an entire upper surface of the second electrode except at the second contact point.
8. The method according to claim 7 , wherein said etch stop layer has a high etch selectivity to the second inter metal dielectric layer.
9. The method according to claim 7 , wherein the etch stop layer comprises a nitride material.
10. The method according to claim 7 , wherein both the inter metal dielectric layers comprises an oxide material.