Yttrium-fluoride-based sprayed coating, sprayed member, and method for producing yttrium-fluoride-based sprayed coating

Patent metadata

Field	Value
Publication number	US-12385122-B2
Application number	US-202017779682-A
Country	US
Kind code	B2
Filing date	Dec 9, 2020
Priority date	Dec 18, 2019
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

According to the present invention, a yttrium-fluoride-based sprayed coating that has a Vickers hardness of 350 or higher, includes a YF 3 crystal phase having an orthorhombic crystal system, and does not include a YF 3 crystal phase having a crystal system other than an orthorhombic crystal system is produced by plasma-spraying a spray powder that includes a YF 3 crystal phase having an orthorhombic crystal system and does not include a YF 3 crystal phase having a crystal system other than an orthorhombic crystal system. In the present invention, it is possible to provide a yttrium-fluoride-based sprayed coating that has a high coating hardness and is such that the amount of particles generated upon exposure to a halogen-based gas plasma is low, and such a sprayed coating is exceptional as a sprayed coating formed on a member for a semiconductor-producing device that is used in a semiconductor production step.

First claim

The invention claimed is:

1. An yttrium-fluoride-based sprayed coating comprising an orthorhombic YF 3 crystal phase and a crystal phase of Y 5 O 4 F 7 , being free of a YF 3 crystal phase other than an orthorhombic YF 3 crystal phase, and having a mean crystallite size of 5 nm to 70 nm that is determined from half widths of diffraction peaks attributed to (101), (020), and (210) planes of the orthorhombic YF 3 crystal phase by a Williamson-Hall method, and a Vickers hardness of 350 or more.

2. The yttrium-fluoride-based sprayed coating according to claim 1 , being free of a Y 2 O 3 crystal phase.

3. The yttrium-fluoride-based sprayed coating according to claim 1 , having a thickness of 10 to 500 μm.

4. The yttrium-fluoride-based sprayed coating according to claim 1 formed on a substrate, wherein, based on an amount of yttrium quantified by
immersing the yttrium-fluoride-based sprayed coating having a predetermined surface area in ultrapure water together with the substrate, performing ultrasonic cleaning at an output of 200 W for 30 minutes, taking out the yttrium-fluoride-based sprayed coating together with the substrate from a cleaning liquid for drying;
subsequently, immersing the yttrium-fluoride-based sprayed coating in ultrapure water together with the substrate, performing ultrasonic treatment at an output of 200 W for 15 minutes, and taking out the yttrium-fluoride-based sprayed coating together with the substrate from a treatment liquid;
subsequently, adding 2 ml of a 5.3 N nitric acid aqueous solution per 20 ml of the treatment liquid to the treatment liquid to dissolve yttrium-based particles dropped from the yttrium-fluoride-based sprayed coating in the treatment liquid; and
quantifying the amount of yttrium contained in the treatment liquid by ICP emission spectrometry,
a value corresponding to a mass of yttrium in the yttrium-based particles per the predetermined surface area is 1 μg/cm 2 or less.

5. A sprayed member comprising a substrate and the yttrium-fluoride-based sprayed coating according to claim 1 formed on the substrate.

6. The sprayed member according to claim 5 , wherein the yttrium-fluoride-based sprayed coating is a single-layer structure coating.

7. The sprayed member according to claim 5 , wherein the sprayed member is for a semiconductor producing apparatus.

8. A producing method for the yttrium-fluoride-based sprayed coating according to claim 1 , the method comprising
a step of plasma spraying of a spray powder including an orthorhombic YF 3 crystal phase and being free of a YF 3 crystal phase other than an orthorhombic YF 3 crystal phase.

9. The producing method according to claim 8 , wherein the plasma spraying is atmospheric plasma spraying.

10. The producing method according to claim 9 , wherein a spray distance in the step of the atmospheric plasma spraying is 50 to 90 mm.

11. The producing method according to claim 8 , wherein the plasma spraying uses a mixed gas containing argon gas and hydrogen gas as a plasma gas.

12. The producing method according to claim 11 , wherein a supply rate of the argon gas is 40 NLPM or more.

13. The producing method according to claim 11 , wherein a supply rate of the hydrogen gas is 8 NLPM or more.

14. The producing method according to claim 8 , wherein the spray powder has an oxygen content of 7 wt % or less.

15. The producing method according to claim 8 , wherein the spray powder contains an yttrium-based crystal phase including only an orthorhombic YF 3 crystal phase or only an orthorhombic YF 3 crystal phase and a crystal phase of yttrium oxyfluoride, and the spray powder is a granulated and unbaked powder or a granulated and baked powder.

16. The producing method according to claim 15 , wherein the yttrium oxyfluoride is one or more selected from Y 5 O 4 F 7 , Y 6 O 5 F 8 , and Y 7 O 6 F 9 .

17. The producing method according to claim 8 , wherein the spray powder contains an yttrium-based crystal phase including only an orthorhombic YF 3 crystal phase and a Y 2 O 3 crystal phase, and the spray powder is a granulated and unbaked powder.

18. The producing method according to claim 8 , being free of a step of heat-treating an yttrium-fluoride-based sprayed coating formed by plasma spraying.

Assignees

• Shinetsu Chemical Co

Inventors

• Iwasaki Ryo
• Hamaya Noriaki
• Taniguchi Yugo

Classifications

• H01J2237/332

  Coating · CPC title

• H01J37/32825

  Working under atmospheric pressure or higher · CPC title

• H01J37/32495 Primary

  Means for protecting the vessel against plasma · CPC title

• H01J37/32449

  Gas control, e.g. control of the gas flow · CPC title

• C01P2006/20

  Powder free flowing behaviour · CPC title