Etching method and etchant

Patent metadata

Field	Value
Publication number	US-10008426-B2
Application number	US-201615254310-A
Country	US
Kind code	B2
Filing date	Sep 1, 2016
Priority date	Nov 27, 2015
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

An etching method for detecting crystal defects, the method includes providing a substrate with an etchant containing hydrogen fluoride, nitric acid, hydrogen chloride, and water. A concave portion on a part having a crystal defect of the substrate is formed by the etchant. The concave portion is examined by a microscope to locate a position of the crystal defect.

First claim

What is claimed is:

1. An etching method for detecting crystal defects, the method comprising:
providing a substrate with an etchant comprising hydrogen fluoride, nitric acid, hydrogen chloride, and water, the substrate having a crystal defect; and
forming a concave portion on the crystal defect by the etchant,
wherein weight composition ratios of hydrogen fluoride, nitric acid, hydrogen chloride, and water in the etchant are (1.7 to 2.4):(30.3 to 49.6):(1.4 to 9.2):(46.5 to 60.1), respectively, and
wherein the etchant does not contain chromium or acetic acid in principle.

2. The method according to claim 1 , further comprising:
using a microscope, locating a position of the crystal defect according to the concave portion.

3. The method according to claim 1 ,
wherein the size of the concave portion is 0.1 μm to 0.3 μm.

4. The method according to claim 1 , further comprising:
forming a film on the part of the substrate having the crystal defect by the etchant; and
removing the film by the etchant to form the concave portion on the substrate.

5. The method according to claim 4 ,
wherein the film is formed by oxidization of the substrate.

6. The method according to claim 1 ,
wherein a treatment time of the substrate by the etchant is 10 seconds to 10 minutes.

7. The method according to claim 1 ,
wherein the etchant does not contain an organic acid in principle.

8. The method according to claim 1 , wherein a weight composition ratio of chromium to H 2 O in the etchant is less than 1:500.

9. The method according to claim 1 , wherein at least one of hydrogen fluoride, nitric acid, hydrogen chloride in the etchant includes ionized molecules.

10. An etching method for detecting crystal defects, the method comprising:
providing a substrate with an etchant comprising an oxidizing agent, an etching agent, hydrogen chloride, and water, the substrate having a crystal defect; and
forming a concave portion on the crystal defect by the etchant,
wherein weight composition ratios of hydrogen fluoride, nitric acid, hydrogen chloride, and water in the etchant are (1.7 to 2.4):(30.3 to 49.6):(1.4 to 9.2):(46.5 to 60.1), respectively, and
wherein the etchant does not contain chromium or acetic acid in principle.

11. The method according to claim 10 , further comprising:
using a microscope, locating a position of the crystal defect according to the concave portion.

12. The method according to claim 10 , wherein the oxidizing agent is nitric acid, and the etching agent is hydrogen fluoride.

13. The method according to claim 10 ,
wherein the size of the concave portion is 0.1 μm to 0.3 μm.

14. The method according to claim 10 ,
wherein a treatment time of the substrate by the etchant is 10 seconds to 10 minutes.

15. The method according to claim 10 ,
wherein the etchant does not contain an organic acid in principle.

16. The method according to claim 10 , wherein a weight composition ratio of chromium to H 2 O in the etchant is less than 1:500.

17. The method according to claim 10 , wherein at least one of hydrogen fluoride, nitric acid, hydrogen chloride in the etchant includes ionized molecules.

Assignees

• Toshiba Memory Corp

Inventors

• Nakai Takehiro
• Tsuchiya Norihiko
• Funo Sakae
• Shimada Junichi
• Itabashi Youko

Classifications

• H10P50/642

  Chemical etching · CPC title

• H10P14/6309

  of silicon in uncombined form, i.e. pure silicon · CPC title

• H10P74/235 Primary

  comprising optical enhancement of defects or not-directly-visible states · CPC title

• C09K13/08

  containing a fluorine compound · CPC title

• H01L21/30604

  Electricity · mapped topic