Method of via filling
A method of processing a substrate includes exposing the substrate to a boron-containing precursor to adsorb over the substrate, where the substrate includes a dielectric layer formed over a conductive layer, and the conductive layer is exposed at a bottom of a recess formed in the dielectric layer. The method includes exposing the adsorbed boron-containing precursor to a plasma and filling the recess with a conductive fill material bottom up by a vapor deposition process, where a vertical deposition rate of the conductive fill material is greater than a lateral deposition rate of the conductive fill material.
1 . A method of processing a substrate, the method comprising:
exposing the substrate to a boron-containing precursor to adsorb over the substrate, the substrate comprising a dielectric layer formed over a conductive layer, the conductive layer being exposed at a bottom of a recess formed in the dielectric layer,
exposing the adsorbed boron-containing precursor to a plasma; and
filling the recess with a conductive fill material bottom up by a vapor deposition process, wherein a vertical deposition rate of the conductive fill material is greater than a lateral deposition rate of the conductive fill material.
2 . The method of claim 1 , wherein the boron-containing precursor comprises a boron halide or a borane.
3 . The method of claim 1 , wherein the boron-containing precursor comprises B 2 H 6 , BF 3 , BCl 3 , or BBr 3 .
4 . The method of claim 1 , wherein the conductive layer comprises ruthenium (Ru), tungsten (W), or titanium (Ti).
5 . The method of claim 1 , wherein the plasma comprises argon and hydrogen.
6 . The method of claim 1 , wherein the dielectric layer comprises silicon oxide, and wherein the exposing to the plasma inducing boron doping in the silicon oxide.
7 . The method of claim 1 , wherein the conductive fill material comprises ruthenium (Ru), tungsten (W), or molybdenum (Mo).
8 . The method of claim 1 , wherein the exposing to the plasma removes boron from the conductive layer.
9 . A method of processing a substrate, the method comprising:
exposing the substrate to BCl 3 to adsorb over a surface of the substrate, the surface comprising a dielectric layer and a conductive layer;
exposing the adsorbed BCl 3 to a plasma comprising argon and hydrogen, the exposing to the plasma incorporating boron into the dielectric layer; and
depositing a metal over the surface, wherein a deposition rate of the metal is greater over the conductive layer than over the dielectric layer.
10 . The method of claim 9 , further comprising, prior to the depositing, repeating the steps of the exposing to BCl 3 and the exposing to the plasma.
11 . The method of claim 9 , wherein the substrate comprises a recess, the conductive layer being exposed at a bottom of the recess and the dielectric layer comprising sidewalls of the recess.
12 . The method of claim 9 , wherein the exposing to BCl 3 is performed in the absence of plasma.
13 . The method of claim 9 , wherein the metal comprises ruthenium (Ru), tungsten (W), or molybdenum (Mo).
14 . The method of claim 9 , wherein the conductive layer comprises titanium nitride or tantalum nitride.
15 . A method of forming a metal interconnect for a semiconductor device, the method comprising:
exposing a substrate comprising a via to a boron-containing precursor to adsorb over sidewalls of the via, the via having a critical dimension of 20 nm or less, a conductive material being exposed at a bottom of the via;
exposing the substrate to a plasma to induce boron doping to the sidewalls; and
filling the via with ruthenium (Ru) by a vapor deposition process, the Ru being deposited preferentially from the bottom of the via than from the sidewalls.
16 . The method of claim 15 , wherein the via has an aspect ratio between 5:1 and 100:1.
17 . The method of claim 15 , wherein the via is filled with Ru without a void.
18 . The method of claim 15 , wherein the boron-containing precursor comprises BCl 3 , and wherein the plasma comprising argon and hydrogen.
19 . The method of claim 15 , wherein the conductive material comprises titanium nitride.
20 . The method of claim 15 , wherein the sidewalls comprise an oxide.