Ultrathin atomic layer deposition film accuracy thickness control

Patent metadata

Field	Value
Publication number	US-2016276148-A1
Application number	US-201514664545-A
Country	US
Kind code	A1
Filing date	Mar 20, 2015
Priority date	Mar 20, 2015
Publication date	Sep 22, 2016
Grant date	—

Abstract

Methods for depositing ultrathin films by atomic layer deposition with reduced wafer-to-wafer variation are provided. Methods involve exposing the substrate to soak gases including one or more gases used during a plasma exposure operation of an atomic layer deposition cycle prior to the first atomic layer deposition cycle to heat the substrate to the deposition temperature.

First claim

1 . A method for depositing a silicon oxide film by atomic layer deposition on a semiconductor substrate, the method comprising:
(a) inserting a substrate into a chamber; (b) after inserting the substrate into the chamber and prior to performing a first cycle of atomic layer deposition at a deposition temperature, raising the substrate's temperature to about the deposition temperature by exposing the substrate to a soak gas for a duration of about 500 seconds or less; and (c) performing the atomic layer deposition, wherein a cycle of the atomic layer deposition comprises exposing the substrate to a silicon-containing precursor in a non-plasma environment for a duration sufficient to substantially adsorb the silicon-containing precursor to the surface of the substrate and exposing the substrate to an oxidant in a plasma environment to form at least a portion of the silicon oxide film, wherein soaking the substrate comprises exposing the substrate to a soak gas comprising only one or more gases used when exposing the substrate to the oxidant in the plasma environment during the atomic layer deposition cycle to form the at least a portion of the silicon oxide film, and wherein the thickness of the silicon oxide film deposited by the atomic layer deposition is less than about 5 nm.

2 . The method of claim 1 , wherein the soak gas in (b) contains only a gas or gases used when exposing the substrate to the oxidant in the plasma environment to form the at least a portion of the silicon oxide film.

3 . The method of claim 1 , wherein the soak gas in (b) comprises two or more gases, and no other gases, used when exposing the substrate to the oxidant in the plasma environment to form the at least a portion of the silicon oxide film, and wherein the two or more gases are present in the soak gas in substantially the same proportion as they are in the oxidant.

4 . The method of claim 1 , wherein the soak gas in (b) is selected from the group consisting of argon, nitrogen, oxygen, nitrous oxide, and combinations thereof.

5 . The method of claim 1 , wherein the soak gas in (b) comprises no helium.

6 . The method of claim 1 , wherein the flow rate of the soak gas in (b) is within about 10% of a maximum flow rate achievable by the chamber.

7 . The method of claim 6 , wherein the flow rate of the soak gas in (b) is at least about 15 slm.

8 . The method of claim 1 , wherein the flow rate of the soak gas in (b) is at least about 25% to about 200% of the flow rate of the one or more gases used when exposing the substrate to the oxidant in the plasma environment during the atomic layer deposition cycle.

9 . The method of claim 1 , wherein wafer-to-wafer variation of the average silicon oxide film thickness over the surface of the substrate is less than about ±2 Å.

10 . (canceled)

11 . The method of claim 10 , wherein between two and about fifty atomic layer deposition cycles are performed.

12 - 15 . (canceled)

16 . A method for depositing a film by atomic layer deposition on a semiconductor substrate, the method comprising:
(a) inserting a substrate into a chamber; and (b) after inserting the substrate into the chamber and prior to performing a first cycle of atomic layer deposition at a deposition temperature, raising the substrate's temperature to about the deposition temperature by exposing the substrate to a soak gas for a duration of about 500 seconds or less; and (c) performing the atomic layer deposition, wherein a cycle of the atomic layer deposition comprises exposing the substrate to a precursor in a non-plasma environment for a duration sufficient to substantially adsorb the precursor to the surface of the substrate, exposing the substrate to a second reactant in a plasma environment to form at least a portion of the film, and wherein soaking the substrate comprises exposing the substrate to a soak gas comprising only one or more gases used when exposing the substrate to the second reactant in the plasma environment during the atomic layer deposition cycle to form the at least a portion of the film, and wherein the thickness of the film deposited by the atomic layer deposition is less than about 5 nm.

17 . The method of claim 16 , wherein the soak gas in (b) contains only a gas or gases used when exposing the substrate to the second reactant in the plasma environment to form the at least a portion of the film.

18 . The method of claim 16 , wherein the soak gas in (b) comprises two or more gases, and no other gases, used when exposing the substrate to the second reactant in the plasma environment to form the at least a portion of the film, and wherein the two or more gases are present in the soak gas in substantially the same proportion as they are in the second reactant.

19 . The method of claim 16 , wherein the soak gas in (b) is selected from the group consisting of argon, nitrogen, oxygen, nitrous oxide, and combinations thereof.

20 . The method of claim 16 , wherein the soak gas in (b) comprises no helium.

21 . The method of claim 16 , wherein the flow rate of the soak gas in (b) is within 10% of a maximum flow rate achievable by the chamber.

22 . The method of claim 21 , wherein the flow rate of the soak gas in (b) is at least about 15 slm.

23 . The method of claim 16 , wherein the flow rate of the soak gas in (b) is at least about 25% to about 200% of the flow rate of the one or more gases used when exposing the substrate to the oxidant in the plasma environment during the atomic layer deposition cycle.

24 . The method of claim 16 , wherein wafer-to-wafer variation of the average film thickness over the surface of the substrate is less than about ±2 Å.

25 - 32 . (canceled)

33 . An apparatus for processing semiconductor substrates, the apparatus comprising:
(a) one or more stations, each reaction station comprising a pedestal for holding a substrate; (b) at least one outlet for coupling to a vacuum; (c) one or more process gas inlets for coupling to precursor and reactant sources; (d) a robot for inserting substrates into the one or more reaction chambers; and (e) a controller for controlling operations in the apparatus, comprising machine-readable instructions for:
(i) inserting a substrate into one of the one or more stations;
(ii) introducing a soak gas for a duration of about 500 seconds or less;
(iii) introducing a silicon-containing precursor for a duration sufficient to substantially adsorb the silicon-containing precursor onto the surface of the substrate;
(iv) introducing a second reactant into the one or more reaction chambers and igniting a plasma; and
(v) repeating (iii) and (iv) to form a film on the substrate, the film having a thickness less than about 5 nm,
wherein the soak gas in (ii) comprises only one or more gases used in (iv).

34 - 35 . (canceled)

Assignees

• Lam Res Corp

Inventors

• Qian Jun
• Kang Hu
• Lavoie Adrien
• Matsuyama Seiji
• Kumar Purushottam

Classifications

• H10P14/69215

  the material being a silicon oxide, e.g. SiO2 · CPC title

• H10P14/6682

  the compound being a silane, e.g. disilane, methylsilane or chlorosilane · CPC title

• H10P14/6336

  in the presence of a plasma [PECVD] · CPC title

• H10P14/6339 Primary

  deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD · CPC title

• C23C16/02 Primary

  Pretreatment of the material to be coated (C23C16/04 takes precedence) · CPC title