Method for forming conformal nitrided, oxidized, or carbonized dielectric film by atomic layer deposition
A method for forming a film on a patterned surface of a substrate by atomic layer deposition (ALD) processing includes: adsorbing onto a patterned surface a first precursor containing silicon or metal in its molecule; adsorbing onto the first-precursor-adsorbed surface a second precursor containing no silicon or metal in its molecule; exposing the second-precursor-adsorbed surface to an excited reactant to oxidize, nitride, or carbonize the precursors adsorbed on the surface of the substrate; and repeating the above cycle to form a film on the patterned surface of the substrate.
1. A method for forming a film on a patterned surface of a substrate by atomic layer deposition (ALD) processing, said surface being patterned with a recess having side walls and a bottom, said ALD processing being constituted by a plurality of atomic layer deposition cycles, each cycle comprising in the following sequence of steps (i) to (iii) using a first precursor containing silicon in its molecule, a second precursor containing no silicon in its molecule, and a reactant for nitriding the precursors, said reactant being neither first nor second precursor, being nitriding gas selected from the group consisting of NH 3 , N x H y , and N x H y C z (x, y, and z are integers) excluding N 2 , and having a smaller molecular size than the second precursor, each cycle being defined as a cycle forming a monolayer using the first precursor and a monolayer using the second precursor, wherein the reactant is continuously supplied to the reaction space throughout steps (i) to (iii):
(i) adsorbing a non-excited gas of the first precursor onto a patterned surface of a substrate in a reaction space by feeding the first precursor to the reaction space in a pulse;
(ia) purging the reaction space between steps (i) and (ib) to purge therefrom the first precursor present in the reaction space;
(ib) applying RF power to the reaction space between steps (ia) and (ii) to excite the reactant to conduct nitridization of the first precursor;
(ii) adsorbing a non-excited gas of the second precursor onto the first-precursor-adsorbed surface of the substrate in the reaction space by feeding the second precursor to the reaction space in a pulse so as to form Si—N—X (X represents an element other than silicon and metal in the second precursor);
(iia) purging the reaction space between steps (ii) and (iii) to purge therefrom the second precursor present in the reaction space where the first precursor is already purged;
(iii) applying RF power to the reaction space between steps (iia) and (iv) to expose the non-excited second-precursor-adsorbed surface of the substrate to an excited gas of the reactant to nitride the precursors adsorbed on the surface of the substrate;
said ALD processing further comprising (iv) repeating the cycle constituted by steps (i) to (iii) to form a film on the patterned surface of the substrate, step (iv) further comprising purging the reaction space between steps (iii) and (i) when repeating the cycle.
2. The method according to claim 1 , wherein the second precursor is at least one compound selected from the group consisting of C x N y H z and N x H y (x, y, and z are integers), whereby the excited reactant nitrides the precursors adsorbed on the surface of the substrate.
3. The method according to claim 1 , wherein the first precursor is at least one selected from the group consisting of dichlorodiethylsilane, dichlorodimethylsilane, dichlorotetramethyldisilazane, dichlorotetraethyldisilazane, dichloroethylsilane, dichloromethylsilane, diiodomethylsilane, diiodoethylsilane.
4. The method according to claim 1 , wherein the first precursor is an aminosilane compound.
5. The method according to claim 4 , wherein the first precursor is at least one selected from the group consisting of bis(diethylamino)silane and bis(dimethylamino)silane.
6. The method according to claim 1 , wherein the first and second precursors are organic compounds which are liquid at room temperature.
7. The method according to claim 1 , wherein the adsorbed weight of the second precursor in step (ii) is equivalent to or higher than the adsorbed weight of the first precursor in step (i).
8. The method according to claim 1 , wherein the reactant is excited by heat and/or a plasma in step (iii).
9. The method according to claim 8 , wherein the reactant is excited by a plasma generated by applying RF power to the reaction space.
10. The method according to claim 1 , further comprising, after step (iv), (v) exposing the film on the substrate to a plasma of an inert gas, a hydrogen-containing gas, ammonium-containing gas, and/or oxidizing gas.
11. The method according to claim 1 , wherein no purge is conducted between steps (ib) and (ii).