Method for processing silicon substrate and method for manufacturing liquid ejection head

Patent metadata

Field	Value
Publication number	US-10464325-B2
Application number	US-201715464903-A
Country	US
Kind code	B2
Filing date	Mar 21, 2017
Priority date	Mar 24, 2016
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

A method for processing a silicon substrate includes forming a structure having a bottom surface and a depth of 200 μm or more or 300 μm or more from a first surface of a silicon substrate, forming a protective film on an inner wall of the structure, and performing plasma etching so as to selectively remove the protective film disposed on the bottom surface of the structure with respect to the protective film disposed on the substantially perpendicular side wall of the structure, wherein the plasma etching is performed under the condition in which plasma with a sheath length at least 10 times the depth when the depth is 200 μm or more, or at least 5 time the depth when the depth is 300 μm or more, is generated and a mean free path of ions generated in the plasma is longer than the sheath length.

First claim

What is claimed is:

1. A method for processing a silicon substrate comprising:
forming a structure having a depth of 200 μm or more from a first surface of a silicon substrate, a side wall, and a bottom surface, at least a part of the side wall being substantially perpendicular to the first surface;
forming a protective film on an inner wall of the structure, the inner wall comprising the side wall and the bottom surface; and
performing plasma etching so as to selectively remove the protective film disposed on the bottom surface of the structure with respect to the protective film disposed on the substantially perpendicular side wall of the structure,
wherein the plasma etching is performed under the condition in which plasma with a sheath length at least 10 times the depth of the structure is generated and a mean free path of ions generated in the plasma is equal to or longer than the sheath length.

2. The method for processing a silicon substrate according to claim 1 , wherein the silicon substrate has a surface that is a (100) plane, and at least a part of the side wall, from the bottom surface in the depth direction, of the structure is substantially perpendicular to the first surface.

3. The method for processing a silicon substrate according to claim 1 , wherein the aspect ratio of the structure is 4 or more.

4. The method for processing a silicon substrate according to claim 1 , wherein the depth of the structure is 500 μm or more.

5. The method for processing a silicon substrate according to claim 4 , wherein the structure penetrates the silicon substrate from the first surface to a second surface opposite to the first surface and the bottom surface of the structure is an etching stop layer disposed on the second surface of the silicon substrate.

6. The method for processing a silicon substrate according to claim 1 , wherein an inductively coupled plasma (ICP) etching system is used in the plasma etching.

7. The method for processing a silicon substrate according to claim 1 , wherein the plasma etching is performed by rare gas ion bombardment.

8. The method for processing a silicon substrate according to claim 1 , wherein the protective film is formed by an atomic layer deposition (ALD) method.

9. The method for processing a silicon substrate according to claim 1 , wherein the protective film is composed of any one of SiO 2 , Al 2 O 3 , Ta 2 O 5 , ZrO, TiO 2 , and HfO 2 .

10. A method for processing a silicon substrate comprising:
forming a structure having a depth of 300 μm or more from a first surface of a silicon substrate, a side wall, and a bottom surface, at least a part of the side wall being substantially perpendicular to the first surface;
forming a protective film on an inner wall of the structure, the inner wall comprising the side wall and the bottom surface; and
performing plasma etching so as to selectively remove the protective film disposed on the bottom surface of the structure with respect to the protective film disposed on the substantially perpendicular side wall of the structure,
wherein the plasma etching is performed under the condition in which plasma with a sheath length at least 5 times the depth of the structure is generated and a mean free path of ions generated in the plasma is equal to or longer than the sheath length.

11. The method for processing a silicon substrate according to claim 10 , wherein the silicon substrate has a surface that is a (100) plane, and at least a part of the side wall, from the bottom surface in the depth direction, of the structure is substantially perpendicular to the first surface.

12. The method for processing a silicon substrate according to claim 10 , wherein the aspect ratio of the structure is 4 or more.

13. The method for processing a silicon substrate according to claim 10 , wherein the depth of the structure is 500 μm or more.

14. The method for processing a silicon substrate according to claim 13 , wherein the structure penetrates the silicon substrate from the first surface to a second surface opposite to the first surface and the bottom surface of the structure is an etching stop layer disposed on the second surface of the silicon substrate.

15. The method for processing a silicon substrate according to claim 10 , wherein an inductively coupled plasma (ICP) etching system is used in the plasma etching.

16. The method for processing a silicon substrate according to claim 10 , wherein the plasma etching is performed by rare gas ion bombardment.

17. The method for processing a silicon substrate according to claim 10 , wherein the protective film is formed by an atomic layer deposition (ALD) method.

18. The method for processing a silicon substrate according to claim 10 , wherein the protective film is composed of a material selected from the group consisting of SiO 2 , Al 2 O 3 , Ta 2 O 5 , ZrO, TiO 2 , and HfO 2 .

19. A method for manufacturing a liquid ejection head comprising the method for processing a silicon substrate according to claim 1 , further comprising forming, on a second surface opposite to the first surface of the silicon substrate, a flow passage forming member constituting an ejection port for ejecting a liquid and a liquid flow passage that communicates with the ejection port,
wherein the structure includes a common liquid chamber composed of the first surface of the silicon substrate and a supply port that communicates with the common liquid chamber and the liquid flow passage from a bottom section of the common liquid chamber.

20. The method for manufacturing a liquid ejection head according to claim 19 , wherein the silicon substrate has a surface that is a (100) plane, and at least a part of the side wall, from the bottom surface in the depth direction, of the structure is substantially perpendicular to the first surface.

Assignees

• Canon Kk

Inventors

• Terasaki Atsunori

Classifications

• B41J2/14032

  Structure of the pressure chamber · CPC title

• B81B2201/052

  Ink-jet print cartridges · CPC title

• B81C2201/014

  by depositing an etch stop layer, e.g. silicon nitride, silicon oxide, metal · CPC title

• B41J2/1629

  wet etching · CPC title

• B81C1/00206

  Processes for functionalising a surface, e.g. provide the surface with specific mechanical, chemical or biological properties · CPC title