Protective coatings resistant to reactive plasma processing
Embodiments of the invention relate to compositions of metal oxyfluoride-comprising glazes or metal fluoride-comprising glazes, glass ceramics, and combinations thereof which are useful as plasma-resistant solid substrates or plasma resistant protective coatings over other substrates. Also described are methods of fabricating various structures which incorporate such compositions, including solid substrates and coatings over the surface of a substrate which has a melting point which is higher than about 1600° C., such as aluminum oxide, aluminum nitride, quartz, silicon carbide, silicon nitride.
1. A method of forming a protective coating over a surface of a component used in a semiconductor plasma processing apparatus, said protective coating comprising a sintered composition including a yttrium-based oxyfluoride crystal phase, in combination with an oxyfluoride-comprising amorphous phase upon at least one surface of a substrate of said component, said method comprising:
a) applying a slurry comprising a powder in suspension over said at least one surface of said substrate, wherein said powder comprises yttrium fluoride, and said substrate is selected to have a melting point higher than about 1600° C.; and
b) sintering said coating present on said substrate surface to produce a sintered coating comprising a yttrium-based oxyfluoride crystal phase, in combination with an oxyfluoride-comprising amorphous phase, where said oxyfluoride-comprising amorphous phase content ranges from about 4.5 molar % to about 22 molar % of said sintered coating composition, whereby said protective coating structure retards crack propagation through said coating;
wherein said substrate is selected from the group consisting of aluminum oxide, aluminum nitride, quartz, silicon carbide, silicon nitride, or a combination thereof, wherein said sintering is carried out in an oxygen-containing environment, and wherein said powder comprises YF 3 at a concentration ranging from about 80 weight % to about 90 weight % in combination with NdF 3 at a concentration ranging from about 20% by weight to about 10% by weight, respectively.
2. A method in accordance with claim 1 , wherein said powder additionally includes a dopant selected from the group consisting of an oxide, fluoride, or oxyfluoride of neodymium, cerium, samarium, erbium, aluminum, scandium, lanthanum, hafnium, niobium, zirconium, ytterbium, and combinations of an oxide, fluoride or oxyfluoride of at least one of these elements.
3. A method in accordance with claim 1 or claim 2 , wherein said slurry comprises said powder suspended in methanol, ethanol, or a combination thereof.
4. A method in accordance with claim 3 , wherein a concentration of methanol, ethanol, or a combination thereof in said slurry ranges from about 30 weight % to about 90 weight %.
5. A method in accordance with claim 1 or claim 2 , wherein said slurry comprises said powder suspended in water and a water soluble polymeric material.
6. A method in accordance with claim 5 , wherein said water soluble polymer is poly vinyl alcohol, polymeric cellulose ether, or a combination thereof.
7. A method in accordance with claim 1 or claim 2 , wherein said substrate is aluminum oxide and said slurry is sintered using a dwell time at a temperature ranging from 1400° C. up to less than 1430° C. for a time period ranging from about 120 minutes to about 180 minutes.
8. A method in accordance with claim 1 or claim 2 , wherein said concentration of NdF 3 is about 20% by weight, and a dwell time at a temperature ranging from 1400° C. to less than 1430° C. is about 180 minutes.
9. A method in accordance with claim 1 or claim 2 , wherein said concentration of NdF 3 is about 10% by weight, and a dwell time at 1430° C. is about 120 minutes.