Methods for depositing films on sensitive substrates

Patent metadata

Field	Value
Publication number	US-2016155676-A1
Application number	US-201615015952-A
Country	US
Kind code	A1
Filing date	Feb 4, 2016
Priority date	Nov 8, 2012
Publication date	Jun 2, 2016
Grant date	—

Abstract

Methods and apparatus to form films on sensitive substrates while preventing damage to the sensitive substrate are provided herein. In certain embodiments, methods involve forming a bilayer film on a sensitive substrate that both protects the underlying substrate from damage and possesses desired electrical properties. Also provided are methods and apparatus for evaluating and optimizing the films, including methods to evaluate the amount of substrate damage resulting from a particular deposition process and methods to determine the minimum thickness of a protective layer. The methods and apparatus described herein may be used to deposit films on a variety of sensitive materials such as silicon, cobalt, germanium-antimony-tellerium, silicon-germanium, silicon nitride, silicon carbide, tungsten, titanium, tantalum, chromium, nickel, palladium, ruthenium, or silicon oxide.

First claim

1 . A method of measuring an extent of damage to a substrate during deposition, the method comprising:
(a) depositing a plurality of film layers by a cyclic deposition method in which each cycle deposits one layer of film; (b) measuring a thickness of the deposited film layers; (c) after (b), depositing one or more additional film layers by the cyclic deposition method; (d) after (c), measuring the thickness of the deposited film layers; (e) performing a linear regression between the number of deposition cycles performed and the measured film thicknesses to form a regression model; (f) using the regression model to evaluate a predicted thickness at about zero deposition cycles, wherein the predicted thickness corresponds to the extent of damage to the substrate experienced during deposition of the film layers.

2 . The method of claim 1 , wherein the film thickness is measured at least three times.

3 . The method of claim 2 , wherein one or more additional film layers are deposited by the cyclic deposition method between each film thickness measurement.

4 . The method of claim 1 , wherein the cyclic deposition method is cycled at least about 5 times before the earliest film thickness measurement is performed.

5 . The method of claim 4 , wherein the cyclic deposition method is cycled at least about 10 times before the earliest film thickness measurement is performed.

6 . The method of claim 1 , wherein the cyclic deposition method comprises:
providing a first reactant to a reaction chamber and allowing the first reactant to adsorb onto a surface of the substrate; providing a second reactant to the reaction chamber; and igniting a plasma in the reaction chamber to drive a reaction between the first reactant and the second reactant when a flow of at least one of the first and second reactants has ceased.

7 . The method of claim 1 , wherein the cyclic deposition method is an atomic layer deposition method.

8 . A method of determining a minimum effective thickness of a protective film layer deposited on a substrate, comprising:
(a) providing a plurality of individual substrates having differing thicknesses of protective films deposited thereon; (b) measuring a pre-plasma thickness of each of the protective films on the individual substrates; (c) after (b), exposing the individual substrates to a plurality of plasma exposure cycles, wherein substantially no material is deposited during the plasma exposure cycles; (d) after (c), measuring a post-plasma thickness of the protective films on the individual substrates; (e) calculating a thickness difference for each individual substrate, the thickness difference corresponding to the pre-plasma thickness minus the post-plasma thickness; (f) determining the minimum effective thickness of the protective film layer by evaluating the protective film thickness at which the thickness difference becomes substantially stable.

9 . The method of claim 8 , wherein the protective film layer comprises silicon oxide.

10 . The method of claim 8 , wherein the protective film layer comprises silicon nitride.

11 . The method of claim 8 , wherein the individual substrates have thicknesses ranging from about 0 Å to about 300 Å.

12 . The method of claim 8 , wherein (c) comprises exposing the individual substrates to 100 plasma exposure cycles.

13 . The method of claim 8 , wherein the plasma exposure cycles comprise exposing the individual substrates to plasma comprising a mixture of O 2 and N 2 O.

14 . The method of claim 9 , further comprising forming a bilayer on an exposed surface of an oxidation-sensitive substrate, the bilayer comprising a first layer and a second layer formed on the first layer, wherein the first layer comprises silicon oxide and has a thickness that is at least about the minimum effective thickness determined in (f).

15 . The method of claim 14 , wherein the first layer of the bilayer is formed using processing parameters that correspond to processing parameters used to form the protective films provided on the individual substrates in (a).

16 . The method of claim 15 , wherein (i) a substrate temperature is higher during formation of the second layer of the bilayer compared to the first layer of the bilayer, and/or (ii) a radio frequency power used to generate or maintain plasma is higher during formation of the second layer of the bilayer compared to the first layer of the bilayer.

17 . The method of claim 10 , further comprising forming a bilayer on an exposed surface of a nitridation-sensitive substrate, the bilayer comprising a first layer and a second layer formed on the first layer, wherein the first layer comprises silicon nitride and has a thickness that is at least about the minimum effective thickness determined in (f).

18 . The method of claim 17 , wherein the first layer of the bilayer is formed using processing parameters that correspond to processing parameters used to form the protective films provided on the individual substrates in (a).

19 . The method of claim 18 , wherein (i) a substrate temperature is higher during formation of the second layer of the bilayer compared to the first layer of the bilayer, and/or (ii) a radio frequency power used to generate or maintain plasma is higher during formation of the second layer of the bilayer compared to the first layer of the bilayer.

20 . The method of claim 14 , wherein the first layer of the bilayer is formed by:
(a) periodically exposing the oxidation-sensitive substrate to a vapor phase flow of a silicon-containing reactant in a reaction chamber; (b) exposing the oxidation-sensitive substrate to a vapor phase flow of an oxidizing reactant in the reaction chamber; and (c) periodically igniting a plasma in the reaction chamber using a high frequency radio frequency power between about 12.5 and about 125 Watts per station when the vapor phase flow of the silicon-containing reactant has ceased, wherein the plasma forms between two electrodes, and wherein the oxidation-sensitive substrate is positioned between the two electrodes.

Assignees

• Novellus Systems Inc

Inventors

• Kang Hu
• Swaminathan Shankar
• Lavoie Adrien
• Henri Jon

Classifications

• H10P74/203

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H10P74/23

  characterised by multiple measurements, corrections, marking or sorting processes · CPC title

• H10P14/69433

  the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz · CPC title

• H10P14/69215

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

• H10P14/6687

  the compound comprising silicon and nitrogen · CPC title