The resonant frequency of a BAW device is inversely proportional to the thickness of the piezoelectric layer in the BAW and of the electrodes above and below the piezoelectric layer. This relationship means that deposition uniformity of the piezoelectric and electrode layers is important to BAW device performance repeatability. For example, the target within-wafer uniformity for an aluminum nitride (AlN) piezoelectric layer can be on the order of 0.5%. By contrast, using conventional PVD techniques, achieving less than 1% within-wafer uniformity for deposited metal films is already a challenge.

Deposition within a PVD process chamber is controlled through a number of variables, including chamber vacuum level, composition of process gases, plasma density and uniformity, bias applied to the wafer, etc. In addition to the above variables, the uniformity and quality of a film deposited via PVD is also highly dependent on the geometry of the PVD process chamber, such as the magnetic profile, and configuration, of the magnetron rotating above the target, the shape of process kit components within the chamber, target-to-wafer spacing, and the like. However, with the exception of target-to-wafer spacing, such geometric factors are generally unchangeable without considerable time and cost to re-engineer some or all such components. Further, any solution based on redesigned process kit components is static, and cannot be tuned or otherwise modified for individual process chambers. As a result, improvements in film uniformity through chamber redesign is a time-consuming and expensive process.

In light of the above, there is a need in the art for systems and methods that enable improved uniformity of deposition during a PVD process.