Abstract: A method for manufacturing an acoustic device includes providing a substrate, providing a bottom electrode over the substrate, providing a sacrificial layer on the bottom electrode, patterning the bottom electrode and the sacrificial layer, polishing the sacrificial layer such that a portion of the sacrificial layer remains on the bottom electrode, and removing the remaining portion of the sacrificial layer via a cleaning process such that a surface roughness of the bottom electrode is maintained. By performing the polishing such that a portion of the sacrificial layer remains on the bottom electrode and subsequently removing that portion of the sacrificial layer via a cleaning process that maintains the surface roughness of the bottom electrode, the subsequent growth of a piezoelectric layer on the bottom electrode can be substantially improved.

Abstract: The present disclosure relates to a Wafer-level-packaged Bulk Acoustic Wave (BAW) device, which includes a bottom electrode, a top electrode, a top electrode lead, a piezoelectric layer sandwiched between the bottom and the top electrodes, an enclosure, and an anti-reflective layer (ARL). Herein, an active region for a resonator is formed where the bottom electrode and the top electrode overlap. The top electrode lead is over the piezoelectric layer and extending from the top electrode. The enclosure includes a cap and an outer wall that extends from the cap toward the piezoelectric layer to form a cavity. The top electrode resides in the cavity and a first portion of the outer wall resides over the top electrode lead. The ARL, with a reflectance less than 40% R, is between the first portion of the outer wall and the top electrode lead.

Abstract: The present disclosure relates to a Wafer-Level-Packaged (WLP) Bulk Acoustic Wave (BAW) device that includes a BAW resonator, a WLP enclosure, and a surface mount connection structure. The BAW resonator includes a piezoelectric layer with an opening and a bottom electrode lead underneath the piezoelectric layer, such that a portion of the bottom electrode lead is exposed through the opening of the piezoelectric layer. The WLP enclosure includes a cap and an outer wall that extends from the cap toward the piezoelectric layer to form a cavity. The opening of the piezoelectric layer is outside the cavity. The surface mount connection structure covers a portion of a top surface of the cap and extends continuously over a side portion of the WLP enclosure and to the exposed portion of the bottom electrode lead through the opening of the piezoelectric layer.

Abstract: The present disclosure relates to a Wafer-Level-Packaged (WLP) Bulk Acoustic Wave (BAW) device that includes a BAW resonator, a WLP enclosure, and a surface mount connection structure. The BAW resonator includes a piezoelectric layer with an opening and a bottom electrode lead underneath the piezoelectric layer, such that a portion of the bottom electrode lead is exposed through the opening of the piezoelectric layer. The WLP enclosure includes a cap and an outer wall that extends from the cap toward the piezoelectric layer to form a cavity. The opening of the piezoelectric layer is outside the cavity. The surface mount connection structure covers a portion of a top surface of the cap and extends continuously over a side portion of the WLP enclosure and to the exposed portion of the bottom electrode lead through the opening of the piezoelectric layer.

Abstract: The present disclosure relates to a Wafer-level-packaged Bulk Acoustic Wave (BAW) device, which includes a bottom electrode, a top electrode, a top electrode lead, a piezoelectric layer sandwiched between the bottom and the top electrodes, an enclosure, and an anti-reflective layer (ARL). Herein, an active region for a resonator is formed where the bottom electrode and the top electrode overlap. The top electrode lead is over the piezoelectric layer and extending from the top electrode. The enclosure includes a cap and an outer wall that extends from the cap toward the piezoelectric layer to form a cavity. The top electrode resides in the cavity and a first portion of the outer wall resides over the top electrode lead. The ARL, with a reflectance less than 40% R, is between the first portion of the outer wall and the top electrode lead.