WORKPIECE PROCESSING METHOD

• US 20200135480A1
• Filed: 12/31/2019
• Published: 04/30/2020
• Est. Priority Date: 08/25/2017
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: TABATA, Masahiro, HISAMATSU, Toru, KIHARA, Yoshihide
• Granted Patent: US 11,133,192 B2
• Time in Patent Office: Days
• CPC Class Codes: H01J 2237/3341 Reactive etching
• CPC Class Codes: H01J 2237/3344 isotropy
• CPC Class Codes: H01J 37/3211 Antennas, e.g. particular shapes of coils
• CPC Class Codes: H01J 37/32458 Vessel
• CPC Class Codes: H01J 37/32724 Temperature
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• 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 21/02332 into an oxide layer, e.g. changing SiO to SiON
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/28132 conducting part of electrode is difined by a sidewall spacer or a similar technique, e.g. oxidation under mask, plating
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/3088 Process specially adapted to improve the resolution of the mask
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/31144 using masks
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/6831 using electrostatic chucks
• CPC Class Codes: H01L 21/6833 Details of electrostatic chucks

Abstract

An embodiment of the present disclosure provides a method of processing a workpiece in which a plurality of holes are formed on a surface of the workpiece. The method includes a first sequence including a first process of forming a film with respect to an inner surface of each of the holes and a second process of isotropically etching the film. The first process includes a film forming process using a plasma CVD method, and the film contains silicon.

Claims

1. A method of processing a workpiece, the method comprising:

providing a workpiece formed with a plurality of holes on a surface thereof in a processing container of a plasma processing apparatus, the plurality of holes including a small diameter hole and a large diameter hole having a diameter larger than the small diameter hole, and the workpiece having an initial size difference which is a difference between a first diameter of the large diameter hole and a second diameter of the small diameter hole;

performing a first sequence on the workpiece including;

a first process of forming a film on an inner surface of each of the plurality of holes by a plasma CVD, a thickness of the film formed on the inner surface of the small diameter hole being smaller than a thickness of the film formed on the inner surface of the large diameter hole; and

a second process of isotropically etching the film such that the small diameter hole is etched to a small hole film inner diameter and the large diameter hole is etched to a large hole film inner diameter,

wherein the workpiece has a post-etch size difference which is a difference between the large hole film inner diameter and the small hole film inner diameter, and the post-etch size difference is smaller than the initial size difference.

2. The method of claim 1, wherein the first process of forming forms a first film on the inner surface of the holes, and a second film on the first film, and an etching resistance of the first film is lower than an etching resistance of the second film in the second process of isotropically etching.

3. The method of claim 1, further comprising repeating the first process and the second process of the first sequence.

4. The method of claim 1, further comprising repeating the first process and the second process of the first sequence,

wherein the post-etch size difference is smaller than the initial size difference such that size differences between the large hole film inner diameter and the small hole film inner diameter progressively become smaller as the first sequence is repeated.

5. The method of claim 1, wherein the workpiece includes a processing target layer and a mask disposed on the processing target layer, and the plurality of holes are formed in the mask.

6. The method of claim 1, wherein the film formed on the inner surface of each of the plurality of holes includes carbon.

7. The method of claim 1, wherein the second process of isotropically etching removes the film by repeating a second sequence including:

generating a first plasma from a first gas which includes nitrogen, and isotropically forming a mixed layer of silicon and nitrogen that include an ion included in the first plasma in the inner surface of the holes;

generating a second plasma from a second gas which includes fluorine and removing the mixed layer by the second plasma.

8. The method of claim 7, wherein the second gas is a mixed gas including NF₃ gas and O₂ gas.

9. The method of claim 7, wherein the second gas is a mixed gas including NF₃ gas, O₂ gas, H₂ gas, and Ar gas or a mixed gas including CH₃F gas, O₂ gas, and Ar gas.

10. The method of claim 7, wherein during the generating the first plasma with the first gas which includes nitrogen, the processing container is maintained at a pressure of 200 mTorr or more, and a surface of the film is modified by nitrogen ions of the first plasma to form a modified surface, and the modified surface includes the silicon nitride and is removed with the second plasma of the second gas which includes fluorine.

11. The method of claim 10, wherein a process time of the generating the first plasma with the first gas which includes nitrogen exceeds a self-control process time such that forming of the modified surface is uniformly performed regardless of hole size.

13. The method of claim 7, wherein the first process of forming forms the first film by repeatedly executing a first film forming sequence including:

supplying a gas which includes an aminosilane-based gas to a processing container of a plasma processing apparatus in which the workpiece is accommodated; and

generating plasma in the processing container of the plasma processing apparatus from a gas which includes oxygen,

wherein the second film is formed by a plasma CVD.

14. The method of claim 13, wherein the gas which includes an aminosilane-based gas includes monoaminosilane.

15. The method of claim 13, wherein the aminosilane-based gas includes aminosilane having one to three silicon atoms or having one to three amino groups.

12. A method of processing a workpiece, the method comprising:

a first sequence including;

a first process of forming a film on an inner surface of each of a plurality of holes formed in the workpiece; and

a second process of isotropically etching the film,

wherein the first process of forming forms a first film on the inner surface of the hole; and

a second film on the first film, and

wherein an etching resistance of the first film is lower than an etching resistance of the second film in the second process of isotropically etching.

16. The method of claim 12, wherein a composition of the first film is different than a composition of the second film.

17. The method of claim 16, wherein the first and second films have different oxygen contents.

18. The method of claim 16, wherein the second film has a higher oxygen content than the first film.

19. The method of claim 16, wherein the first film and the second film are each selected from a silicon-containing film, a boron-containing film, a metal film, and a carbon-containing film.

20. A method comprising:

providing a workpiece including a first hole having a first diameter and a second hole having a second diameter, the second diameter being larger than the first diameter, the workpiece having an initial size difference between the first diameter and the second diameter;

performing a first sequence on the workpiece, the first sequence including;

a first process of performing a plasma CVD on the workpiece such that a first film is formed on an inner surface of the first hole and a second film is formed on an inner surface of the second hole, the first film having a thickness smaller than the second film; and

a second process of isotropically etching the first film and the second film,

wherein the workpiece after the first sequence has a post-etch size difference between the large hole film inner diameter and the small hole film inner diameter, and the post-etch size difference is smaller than the initial size difference.