Dielectric gapfill of high aspect ratio features utilizing a sacrificial etch cap layer

Patent metadata

Field	Value
Publication number	US-2019080903-A1
Application number	US-201715703917-A
Country	US
Kind code	A1
Filing date	Sep 13, 2017
Priority date	Sep 13, 2017
Publication date	Mar 14, 2019
Grant date	—

Abstract

Methods and apparatuses for depositing material into high aspect ratio features, features in a multi-laminate stack, features having positively sloped sidewalls, features having negatively sloped sidewalls, features having a re-entrant profile, and/or features having sidewall topography are described herein. Methods involve depositing a first amount of material, such as a dielectric (e.g., silicon oxide), into a feature and forming a sacrificial helmet on the field surface of the substrate, etching some of the first amount of the material to open the feature opening and/or smoothen sidewalls of the feature, and depositing a second amount of material to fill the feature. The sacrificial helmet may be the same as or different material from the first amount of material deposited into the feature.

First claim

1 . A method of filling a feature on a substrate, the method comprising:
providing the substrate comprising the feature to a process chamber, the feature comprising a feature opening and sidewalls, the sidewalls having sidewall topography comprising stubs on a surface of the sidewall and regions between the stubs; depositing a first amount of silicon oxide into the feature conformally over the sidewall topography for a duration insufficient to fill the feature using a silicon-containing precursor and an oxidant to form the first amount of the silicon oxide having the sidewall topography; exposing the first amount of the silicon oxide to an etchant to etch some of the first amount of the silicon oxide to smoothen the sidewall topography of the first amount of the silicon oxide and form an etched first amount of the silicon oxide; and after etching the first amount of the silicon oxide, depositing a second amount of the silicon oxide over the etched first amount of the silicon oxide.

2 . The method of claim 1 , wherein the stubs of the surface prior to depositing the first amount of silicon oxide have a dimension perpendicular to a planar surface of the sidewall of between 20 Å and about 300 Å.

3 . The method of claim 1 , wherein the duration insufficient to deposit the first amount of the silicon oxide into the feature forms an overburden of silicon oxide on a field surface of the substrate.

4 . The method of claim 3 , wherein exposing the first amount of the silicon oxide to the etchant comprises preferentially etching the some of the first amount of the silicon oxide at or near regions between the stubs at the feature opening relative to inside the feature.

5 . The method of claim 1 , wherein the second amount of the silicon oxide is deposited by plasma-enhanced chemical vapor deposition.

6 . The method of claim 5 , further comprising after depositing the second amount of the silicon oxide, exposing the second amount of the silicon oxide to the etchant for a duration longer than the duration used for exposing the first amount of the silicon oxide to the etchant.

7 . The method of claim 1 , wherein the sidewalls of the feature comprise two or more materials layered in a stack.

8 . The method of claim 1 , wherein the depositing of the first amount of the silicon oxide and the exposing of the first amount of the silicon oxide to the etchant are performed without breaking vacuum.

9 . The method of claim 1 , wherein the exposing of the first amount of the silicon oxide to the etchant and the depositing of the second amount of the silicon oxide are performed without breaking vacuum.

10 . The method of claim 1 , wherein the first amount of the silicon oxide is deposited by one or more cycles of atomic layer deposition, each cycle of atomic layer deposition comprising alternating pulses of the oxidant and the silicon-containing precursor.

11 . The method of claim 10 , wherein a plasma is ignited during pulses of the oxidant.

12 . The method of claim 1 , wherein the etchant is selected from the group consisting of nitrogen trifluoride, fluoroform (CHF3), octafluorocyclobutane (C4F8), tetrafluoromethane (CF4), and combinations thereof.

13 . The method of claim 1 , wherein the feature has a depth of between about 0.5 microns and 6 microns.

14 . The method of claim 1 , wherein the feature has an aspect ratio of at least 6:1.

15 . A method of filling a feature on a substrate, the method comprising:
providing the substrate comprising the feature to a process chamber, the feature comprising a feature opening and sidewalls, the sidewalls having sidewall topography comprising stubs on a surface of the sidewall and regions between the stubs; depositing a first amount of silicon oxide into the feature conformally over the sidewall topography for a duration insufficient to fill the feature using a silicon-containing precursor and an oxidant to form the first amount of the silicon oxide having the sidewall topography; after depositing the first amount of silicon oxide and prior to exposing the first amount of silicon oxide to an etchant, depositing a sacrificial helmet forming an overburden on a field surface of the substrate; exposing the substrate to the etchant to etch some of the first amount of the first amount of the silicon oxide to smoothen the sidewall topography of the first amount of the silicon oxide and form an etched first amount of the silicon oxide; and after etching the first amount of the silicon oxide, depositing a second amount of the oxide over the etched first amount of the silicon oxide to at least partially fill the feature.

16 . The method of claim 15 , wherein sacrificial helmet is deposited by plasma enhanced chemical vapor deposition.

17 . The method of claim 15 , wherein the sacrificial helmet comprises silicon nitride or silicon oxide.

18 . (canceled)

19 . The method of claim 15 , wherein the sacrificial helmet comprises material different from the silicon oxide deposited in the feature.

20 . The method of claim 5 , further comprising after depositing the second amount of the silicon oxide, exposing the second amount of the silicon oxide to the etchant for a duration shorter than the duration used for exposing the first amount of the silicon oxide to the etchant.

21 . The method of claim 14 , wherein the feature has an aspect ratio of at least 15:1.

Assignees

• Lam Res Corp

Inventors

• Abel Joseph
• Agarwal Pulkit
• Phillips Richard
• Kumar Purushottam
• Lavoie Adrien

Classifications

• H10P72/0602

  Temperature monitoring · CPC title

• H10P72/0432

  mainly by conduction · CPC title

• H10P72/0402

  Apparatus for fluid treatment (H10P72/0441, H10P72/0448 take precedence) · CPC title

• H10P14/69433

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

• H10P95/064

  the removal being chemical etching · CPC title