Various manufacturing processes expose chamber components and their coating materials to high temperatures, high energy plasma, a mixture of corrosive gases, high stress, and combinations thereof. Rare earth oxides are frequently used in chamber component manufacturing due to their resistance to erosion from plasma etch chemistries. However, exposure of rare earth oxides to fluorine based plasma can cause cracking and shedding of particles onto wafers.
Furthermore, oxide coatings such as Y2O3 are permeable to water and can cause the adsorption of water. As a result, exposure of oxide coatings such as Y2O3 coatings to air generally causes a brittle M(OH) layer (e.g., a Y(OH)3 layer) to form at a surface of the oxide coating, where M is a metal. Tests have shown the presence of multiple —OH groups at the surface of Y2O3 coatings exposed to air. The M(OH) layer is brittle and can shed particles onto processed wafers. Additionally, the M(OH) layer causes increased leakage current in the metal oxide coating (e.g., in the Y2O3 coating).
In some instances YF3 has been used as a coating for chamber components. Use of the YF3 coating can mitigate the issue of yttrium based particles on processed wafers. However, applying a YF3 coating to chamber components of an etch reactor has been shown to cause a significant etch rate drop (e.g., an etch rate drop of as much as 60%), process drift and chamber matching issues.