Single-Wafer Combinatorial Optimization of Border Rings for Bulk Acoustic Wave Filters

• Published in: Journal of microelectromechanical systems Vol. 33; no. 4; pp. 468 - 472
• Main Authors: Talley, Kevin R., Taber, Benjamen N., Morton, Rick, Brainerd, Steve K., Fox, Austin J.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.08.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustic waves; border ring; bulk acoustic wave (BAW) device; Combinatorial analysis; Design factors; Design of experiments; Design optimization; Electromagnetic wave filters; Filters; Insertion loss; Optimization; Passband; Performance evaluation; Photoresists; radio frequency (RF) filter; Resists; semiconductor process optimization; single-wafer experiment; Thickness
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2024.3409155

Optimization of bulk acoustic wave (BAW) resonator border ring (BR) thicknesses and widths has traditionally been done using multi-wafer splits, often in combination with modeling techniques. Here we describe a single-wafer, two-factor experimental design with 21 distinct experimental regions where we employed custom ion trim and photoresist exposure procedures to optimize BR thickness and width. This resulted in a methodology for optimizing device performance in a manner that reduces the time and cost compared to traditional methods. Though we applied this experimental design to investigating the impact of BR thickness and width on radio frequency BAW filter passband performance, it is generalizable, thereby enabling single-wafer multi-factor experimental designs across an array of device components. [2024-0039]