Fabrication method for semiconductor integrated devices
View Patent ↗A process for forming the lower and upper electrodes of a high dielectric constant capacitor in a semiconductor device from an organoruthenium compound by chemical vapor deposition. This chemical vapor deposition technique employs an organoruthenium compound, an oxidizing gas, and a gas (such as argon) which is hardly adsorbed to the ruthenium surface or a gas (such as ethylene) which is readily adsorbed to the ruthenium surface. This process efficiently forms a ruthenium film with good conformality in a semiconductor device.
1. A process for producing a semiconductor device, comprising the step of:
forming a ruthenium film on the surface of a substrate which has a concave portion, said forming step utilizing chemical vapor deposition from an organoruthenium compound as a precursor in the presence of an oxidizing gas and a gas which has a lower tendency to be adsorbed to a surface of the ruthenium film than the oxidizing gas and which at least partially interrupts the oxidizing gas from reacting with the organoruthenium compound,
wherein a partial pressure of said oxidizing gas is smaller than a partial pressure of said gas which has a lower tendency to be adsorbed to the surface of the ruthenium film, and
further wherein said oxidizing gas has a partial pressure of less than 0.01 Torr in a film-forming chamber in which the chemical vapor deposition takes place.
2. A process for producing a semiconductor device as defined in claim 1 , wherein said chemical vapor deposition is conducted under a condition in which the density of the oxidizing gas adsorbed to a surface of the ruthenium film is lower than if the chemical vapor deposition was carried out in the absence of said gas which has a lower tendency to be adsorbed to the surface of the ruthenium film.
3. A process for producing a semiconductor device as defined in claim 1 , wherein the oxidizing gas is selected from the group consisting of O 2 , N 2 O, NO, O 3 , and H 2 O.
4. A process for producing a semiconductor device as defined in claim 1 , wherein the gas which has a lower tendency to be adsorbed to a surface of the ruthenium film is at least one gas selected from the group consisting of Ar, Ne, He, Xe, N 2 , and CO 2 .
5. A process for producing a semiconductor device as defined in claim 1 , further comprising the step of:
before said chemical vapor deposition forming step, forming a seed layer from at least one material selected from the group consisting of ruthenium, platinum, iridium, rhodium, osmium, palladium, cobalt, iron, and an alloy thereof.
6. A process for producing a semiconductor device as defined in claim 1 , wherein the organoruthenium compound is at least one compound selected from the group consisting of bis(cyclopentadienyl)ruthenium, bis(methylcyclopentadienyl)ruthenium, bis(ethylcyclopentadienyl)ruthenium, and tris(dipivaloylmethanate)ruthenium.
7. A process for producing a semiconductor device as defined in claim 3 , wherein the organoruthenium compound is at least one compound selected from the group consisting of bis(cyclopentadienyl)ruthenium, bis(methylcyclopentadienyl)ruthenium, bis(ethylcyclopentadienyl)ruthenium, and tris(dipivaloylmethanate)ruthenium.
8. A process for producing a semiconductor device, said process comprising the steps of:
providing a substrate;
depositing, via chemical vapor deposition, a ruthenium film on said substrate from an organoruthenium compound as a precursor in the presence of an oxidizing gas and a gas which at least partially limits the ability of the oxidizing gas to be adsorbed to a surface of the ruthenium film,
wherein a partial pressure of said oxidizing gas is smaller than a partial pressure of said gas which at least partially limits the ability of the oxidizing gas to be adsorbed to a surface of the ruthenium film, and
further wherein said oxidizing gas has a partial pressure of less than 0.01 Torr in a film-forming chamber in which the chemical vapor deposition takes place.