Continuous process incorporating atomic layer etching

• US 9,627,221 B1
• Filed: 12/28/2015
• Issued: 04/18/2017
• Est. Priority Date: 12/28/2015
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM IP Holding B.V. (ASM International NV)
• Inventors: Zaitsu, Masaru, Fukazawa, Atsuki, Fukuda, Hideaki
• Primary Examiner(s): Olsen, Allan
• Application Number:
  US14/981,434
• Time in Patent Office: 477 Days
• Field of Search: None
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/45534 Use of auxiliary reactants other than used for contributing to the composition of the main film, e.g. catalysts, activators or scavengers
• CPC Class Codes: C23C 16/4554 Plasma being used non-continuously in between ALD reactions C23C16/56 takes precedence
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/32091 the radio frequency energy being capacitively coupled to the plasma
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02219 the compound comprising silicon and nitrogen
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/31116 by dry-etching

Abstract

A method of continuous fabrication of a layered structure on a substrate having a patterned recess, includes: (i) forming a dielectric layer on a substrate having a patterned recess in a reaction chamber by PEALD using a first RF power; (ii) continuously after completion of step (i) without breaking vacuum, etching the dielectric layer on the substrate in the reaction chamber by PEALE using a second RF power, wherein a pressure of the reaction chamber is controlled at 30 Pa to 1,333 Pa throughout steps (i) and (ii); a noble gas is supplied to the reaction chamber continuously throughout steps (i) and (ii); and the second RF power is higher than the first RF power.

Claims

1. A method of continuous fabrication of a layered structure on a substrate having a patterned recess, comprising:

(i) forming a dielectric layer on a substrate having a patterned recess in a reaction chamber by plasma-enhanced atomic layer deposition (PEALD) using a first RF power;

(ii) continuously from completion of step (i) without breaking vacuum, etching the dielectric layer on the substrate in the reaction chamber by plasma-enhanced atomic layer etching (PEALE) using a second RF power,

wherein a pressure of the reaction chamber is controlled at 30 Pa to 1,333 Pa throughout steps (i) and (ii);

a noble gas is supplied to the reaction chamber continuously throughout steps (i) and (ii); and

the second RF power is higher than the first RF power.

2. The method according to claim 1, wherein step (ii) comprises:

a PEALE cycle comprising;

(iia) supplying a pulse of an etchant gas to the reaction chamber to chemisorb the etching gas in an unexcited state on a surface of the substrate in the reaction chamber; and

(iib) applying a pulse of RF power to the reaction chamber to generate a reactive species of the noble gas and to contact the etchant gas-chemisorbed surface of the substrate with the reactive species so that the dielectric layer on the substrate is etched, wherein a portion of the dielectric layer on a top surface of the substrate is more etched than a portion of the dielectric layer on a sidewall of the recess.

3. The method according to claim 2, wherein the etchant is a fluorocarbon.

4. The method according to claim 2, wherein the patterned recess of the substrate is formed by a photoresist, and the dielectric layer is deposited on the substrate, wherein step (ii) is stopped when a portion of the dielectric layer on a top surface of the substrate is removed so as to expose the photoresist therefrom, and the method further comprises, continuously from step (ii) without breaking vacuum, (iii) ashing the photoresist by a plasma in the reaction chamber.

5. The method according to claim 4, wherein the plasma for ashing is an oxygen plasma.

6. The method according to claim 2, wherein step (ii) further comprises:

a surface treatment cycle comprising;

after step (iib), supplying an oxygen-containing gas to the reaction chamber; and

applying a pulse of RF power to the reaction chamber to generate an oxygen plasma to further etch the dielectric layer, wherein the portion of the dielectric layer on the sidewall of the recess is more etched than the portion of the dielectric layer on the top surface of the substrate.

7. The method according to claim 6, wherein the oxygen-containing gas is oxygen.

8. The method according to claim 6, wherein at least one surface treatment cycle is conducted after every at least one PEALE cycle or after completion of the PEALE cycles.

9. The method according to claim 6, wherein a duration of the pulse of RF power in the surface treatment cycle is longer than a duration of the pulse of RF power in the PEALE cycle.

10. The method according to claim 1, wherein the dielectric layer is a silicon oxide layer.

11. The method according to claim 1, further comprising, followed continuously by step (i) without breaking vacuum, forming a pre-coat layer on the substrate in the reaction chamber.

12. The method according to claim 11, wherein the pre-coat layer is constituted by a material which is the same as that constituting the dielectric layer.

13. The method according to claim 1, wherein the patterned recess has a depth of 10 nm to 1,000 nm, and an aspect ratio of 1 to 5.

14. The method according to claim 1, wherein the dielectric layer has a thickness of 10 nm to 100 nm.

15. The method according to claim 1, wherein a plasma used for the PEALD and PEALE is generated in situ in the reaction chamber using capacitive coupling-type electrodes provided in the reaction chamber.

16. The method according to claim 1, wherein the noble gas is a carrier gas for a precursor for the PEALD, and in step (ii), the carrier gas is fed to the reaction chamber without the precursor.

17. The method according to claim 1, wherein the pressure of the reaction chamber is maintained at a substantially constant level through steps (i) and (ii).