Views: 1 Author: Site Editor Publish Time: 2017-07-19 Origin: Site
A great deal of research has been directed toward improving the microstructure of sputtering targets. Key target properties and challenges that impact thin film functionality and device yield include:
Chemical purity: Elemental impurities in sputtering targets are undesirable as they transfer to the thin film and adversely impact performance. However, higher purity metals are weaker and less able to withstand the stresses induced in the sputtering chamber. This poses unique manufacturing and end-use challenges unlike most other uses of metallic products.
Metallurgical defects: Thin film particulate contamination has been an ongoing and growing challenge with each successive technology node. Porosity, inclusions, inconsistent grain structures, and large second phases present in the target material can — through arcing — cause direct or indirect particulate contamination on the wafer.
Thermal stability: High thermal stability in the target material is needed to withstand high-power sputtering applications.
Target grain size: Fine grain size provides higher strength and contributes to superior film uniformity. Consistent grain structure throughout the target provides stable uniformity through target life.
Target strength: Sufficient yield strength is required to prevent target warping, which can contribute to film non-uniformity and arcing.