Rare earth element oxyflouride powder spray material and sprayed article

Abstract

A spray material comprising rare earth element oxyfluoride particles having an aspect ratio of up to 2, an average particle size of 10-100 μm, and a bulk density of 0.8-2 g / cm3, and containing not more than 0.5 wt % of carbon and 3-15 wt % of oxygen is suitable for air plasma spraying. An article having a sprayed coating of rare earth element oxyfluoride has high resistance against plasma etching and a long lifetime.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2012-183302 filed in Japan on Aug. 22, 2012, the entire contents of which are hereby incorporated by reference.TECHNICAL FIELD[0002]This invention relates to a thermal spraying material in the form of rare earth element oxyfluoride powder, especially suited for use to form a sprayed coating having high corrosion resistance in a corrosive plasma atmosphere as encountered in the semiconductor device fabrication process, and an article having a sprayed coating of the thermal spraying material.BACKGROUND ART[0003]In the prior art, sprayed coatings having high corrosion resistance are used for protecting substrates in a variety of service environments. While aluminum, chromium and similar metal oxides are often used as the thermal spray material, the sprayed coatings of these oxide materials are susceptible to corrosion upon exposure to hot plasma...

AI Technical Summary

Benefits of technology

[0015]The spray material in the form of rare earth element oxyfluoride powder is amenable to atmospheric plasma spraying. An article having a sprayed coating of the rare earth element oxyfluoride has higher resistance against plasma etching than those articles having sprayed coatings of rare earth element oxide and fluoride when used in a halogen gas plasma. High corrosion resistance ensures a long lifetime.

Problems solved by technology

While aluminum, chromium and similar metal oxides are often used as the thermal spray material, the sprayed coatings of these oxide materials are susceptible to corrosion upon exposure to hot plasma.

These materials are thus inadequate for use in the semiconductor manufacturing process which may typically involve treatment in a halogen-based corrosive gas plasma atmosphere.

On the other hand, the rare earth element fluoride sprayed coatings suffer from a technical problem despite good corrosion resistance.

The plasma spraying of rare earth element fluoride has the problem that when the rare earth element fluoride is passed through a flame at 3,000° C. or higher for melting, the fluoride can be decomposed so that the material partially converts to a mixture of rare earth element fluoride and rare earth element oxide.