US 9,824,884 B1Granted

Method for depositing metals free ald silicon nitride films using halide-based precursors

AssigneeLam Research Corporation

InventorsJames S. Sims, Jon Henri, Ramesh Chandrasekharan, Andrew John McKerrow, Seshasayee Varadarajan, Kathryn Merced Kelchner

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Abstract

A method of depositing silicon nitride films on semiconductor substrates processed in a micro-volume of a plasma enhanced atomic layer deposition (PEALD) reaction chamber wherein a single semiconductor substrate is supported on a ceramic surface of a pedestal and process gas is introduced through gas outlets in a ceramic surface of a showerhead into a reaction zone above the semiconductor substrate, includes (a) cleaning the ceramic surfaces of the pedestal and showerhead with a fluorine plasma, (b) depositing a halide-free atomic layer deposition (ALD) oxide undercoating on the ceramic surfaces, (c) depositing a precoating of ALD silicon nitride on the halide-free ALD oxide undercoating, and (d) processing a batch of semiconductor substrates by transferring each semiconductor substrate into the reaction chamber and depositing a film of ALD silicon nitride on the semiconductor substrate supported on the ceramic surface of the pedestal.

Claims16

Dependent claims

(a) cleaning the ceramic surfaces of the pedestal and showerhead with a fluorine plasma;
(b) depositing a halide-free atomic layer deposition (ALD) oxide undercoating on the ceramic surfaces;
(c) depositing a precoating of ALD silicon nitride on the halide-free ALD oxide undercoating;
and
(d) processing a batch of semiconductor substrates by transferring each semiconductor substrate into the reaction chamber and depositing a film of ALD silicon nitride on the semiconductor substrate supported on the ceramic surface of the pedestal;
wherein step (b) is carried out by (i) introducing a flow of a halogen-free silicon-containing first reactant in vapor phase into the reaction chamber and allowing the first reactant to adsorb onto the interior surfaces of the reaction chamber;
(ii) introducing a flow of an oxygen-containing second reactant in vapor phase into the reaction chamber while the first reactant is adsorbed on the interior surfaces of the reaction chamber;
and (iii) exposing the reaction chamber to plasma when the flow of at least one of the first and second reactants has ceased, in order to drive a reaction between the first and second reactants on the interior surfaces of the reaction chamber to form the undercoating, where the undercoating conformally coats the interior surfaces of the reaction chamber;
where operations (i)-(iii) occur when there is no substrate present in the reaction chamber, and where operations (i)-(iii) are repeated until the undercoating is at least about 500 Å thick.

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(a) cleaning the ceramic surfaces of the pedestal and showerhead with a fluorine plasma;
(b) depositing a halide-free atomic layer deposition (ALD) oxide undercoating on the ceramic surfaces;
(c) depositing a precoating of ALD silicon nitride on the halide-free ALD oxide undercoating;
and
(d) processing a batch of semiconductor substrates by transferring each semiconductor substrate into the reaction chamber and depositing a film of ALD silicon nitride on the semiconductor substrate supported on the ceramic surface of the pedestal;
wherein step (c) is carried out by (i) introducing a flow of a halosilane, iodosilane or bromosilane first reactant in vapor phase into the reaction chamber and allowing the first reactant to adsorb onto the interior surfaces of the reaction chamber;
(ii) introducing a flow of a nitrogen-containing second reactant in vapor phase into the reaction chamber while the first reactant is adsorbed on the interior surfaces of the reaction chamber;
and (iii) exposing the reaction chamber to plasma when the flow of at least one of the first and second reactants has ceased, in order to drive a reaction between the first and second reactants on the interior surfaces of the reaction chamber to form the undercoat, where the pre-coating conformally coats the interior surfaces of the reaction chamber;
where operations (i)-(iii) occur when there is no substrate present in the reaction chamber, and where operations (i)-(iii) are repeated until the pre-coating is at least about 500 Å thick.

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Dependencies are inferred from the claim text.