Plug protection process for use in the manufacture of embedded dynamic random access memory (DRAM) cells

Claim 1

A method for forming a semiconductor device, the method comprising the steps of: forming a transistor within a substrate, the transistor having a first current electrode and a second current electrode; forming a first conductive contact plug to the first current electrode of the transistor; forming a second conductive contact plug, separated from the first conductive contact plug, in contact with the second current electrode of the transistor; forming a first barrier region and a second barrier region wherein the first barrier region overlies the first conductive contact plug and the second barrier region overlies the second conductive contact plug; forming a capacitor dielectric in contact with the first barrier region, the capacitor dielectric being exposed to an ambient wherein the second barrier region prevents the ambient from coming into substantial contact with the second conductive contact plug whereby oxidation of the first and second conductive plug is substantially avoided; forming at least one top electrode conductive layer over the capacitor dielectric; and etching portions of the at least one top electrode conductive layer from the semiconductor device whereby a capacitor is formed in electrical contact with the first conductive contact plug.

Claim 2

A method for forming a semiconductor device, the method comprising the steps of: forming a transistor within a substrate, the transistor having a first current electrode and a second current electrode; forming a first conductive contact plug to the first current electrode of the transistor; forming a second conductive contact plug, separated from the first conductive contact plug, in contact with the second current electrode of the transistor; forming a first barrier region and a second barrier region wherein the first barrier region overlies the first conductive contact plug and the second barrier region overlies the second conductive contact plug; forming a capacitor dielectric in contact with the first barrier region, the capacitor dielectric being exposed to an ambient wherein the second barrier region prevents the ambient from coming into substantial contact with the second conductive contact plug whereby oxidation of the first and second conductive plug is substantially avoided; forming at least one top electrode conductive layer over the capacitor dielectric; and etching portions of the at least one top electrode conductive layer from the semiconductor device whereby a capacitor is formed in electrical contact with the first conductive contact plug.

Claim 24

A method for forming a semiconductor device, the method comprising the steps of: forming a transistor within a substrate, the transistor having a first current electrode and a second current electrode; forming a first conductive contact plug to the first current electrode of the transistor and a second conductive contact plug in contact with the second current electrode of the transistor, both the first and second conductive contact plugs comprising tungsten and being formed by chemical mechanical polishing a layer comprising tungsten; forming a first barrier region and a second barrier region wherein the first barrier region overlies the first conductive contact plug and the second barrier region overlies the second conductive contact plug, the first barrier region being made at least partially from iridium and functioning as at least a portion of a bottom capacitor electrode; forming a capacitor dielectric in contact with the first barrier region, the capacitor dielectric being exposed to an oxygen ambient wherein the second barrier region prevents the oxygen ambient from oxidizing the second conductive contact plug; forming a top electrode conductive layer comprising iridium over the capacitor dielectric to form at least part of a top capacitor electrode; etching portions of the top electrode conductive layer, the capacitor dielectric, and the second barrier region from the semiconductor device whereby a capacitor is formed in electrical contact with the first conductive contact plug; and forming a third and fourth conductive plug wherein the third conductive plug forms a bit line contact to the second conductive contact plug and the fourth conductive contact plug electrically contacts the top capacitor electrode.

Claim 25

A method for forming a semiconductor device, the method comprising the steps of: forming a transistor within a substrate, the transistor having a first current electrode and a second current electrode; forming a first conductive contact plug to the first current electrode of the transistor and a second conductive contact plug in contact with the second current electrode of the transistor, both the first and second conductive contact plugs comprising tungsten and being formed by chemical mechanical polishing a layer comprising tungsten; forming a first barrier region and a second barrier region wherein the first barrier region overlies the first conductive contact plug and the second barrier region overlies the second conductive contact plug, the first barrier region being made at least partially from iridium and functioning as at least a portion of a bottom capacitor electrode; forming a capacitor dielectric in contact with the first barrier region, the capacitor dielectric being exposed to an oxygen ambient wherein the second barrier region prevents the oxygen ambient from oxidizing the second conductive contact plug; forming a top electrode conductive layer comprising iridium over the capacitor dielectric to form at least part of a top capacitor electrode; etching portions of the top electrode conductive layer, the capacitor dielectric, and the second barrier region from the semiconductor device whereby a capacitor is formed in electrical contact with the first conductive contact plug; and forming a third and fourth conductive plug wherein the third conductive plug forms a bit line contact to the second conductive contact plug and the fourth conductive contact plug electrically contacts the top capacitor electrode.

Claim 26

A method for forming a semiconductor device, the method comprising the steps of: forming a tungsten plug connected to a current electrode of a transistor; forming a first iridium layer on top of the tungsten plug, the first iridium layer functioning as at least a portion of a bottom capacitor electrode; forming a ferroelectric dielectric overlying the first iridium layer; exposing the ferroelectric dielectric to an oxygen anneal whereby the tungsten plug is protected from the oxygen anneal by the first iridium layer; and forming a conductive layer over the ferroelectric dielectric, the conductive layer functioning as at least a portion of a top capacitor electrode.

Claim 27

A method for forming a semiconductor device, the method comprising the steps of: forming a tungsten plug connected to a current electrode of a transistor; forming a first iridium layer on top of the tungsten plug, the first iridium layer functioning as at least a portion of a bottom capacitor electrode; forming a ferroelectric dielectric overlying the first iridium layer; exposing the ferroelectric dielectric to an oxygen anneal whereby the tungsten plug is protected from the oxygen anneal by the first iridium layer; and forming a conductive layer over the ferroelectric dielectric, the conductive layer functioning as at least a portion of a top capacitor electrode.

Claim 34

A method for forming a semiconductor device, the method comprising the steps of: forming a plurality of conductive plugs comprising tungsten on the semiconductor device, a first set of the plurality of conductive plugs contacting MOS logic gates in the semiconductor device and a second set of the plurality of conductive plugs which are different from the first set contacting a DRAM capacitor within the semiconductor device; and forming an iridium layer which forms a plurality of iridium DRAM capacitor electrodes overlying the second set of conductive plugs and forms protection regions over the MOS logic gates; eventually removing portions of the iridium layer over the first set of conductive plugs so that no iridium overlies the first set of conductive plugs of the semiconductor device.

Claim 35

A method for forming a semiconductor device, the method comprising the steps of: forming a plurality of conductive plugs comprising tungsten on the semiconductor device, a first set of the plurality of conductive plugs contacting MOS logic gates in the semiconductor device and a second set of the plurality of conductive plugs which are different from the first set contacting a DRAM capacitor within the semiconductor device; and forming an iridium layer which forms a plurality of iridium DRAM capacitor electrodes overlying the second set of conductive plugs and forms protection regions over the MOS logic gates; eventually removing portions of the iridium layer over the first set of conductive plugs so that no iridium overlies the first set of conductive plugs of the semiconductor device.