# US 12,113,503 B2 · Manufacturing process for bulk acoustic resonator, and bulk acoustic resonator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,113,503 B2 - Document ID: US12113503B2 - Status: Granted - Kind: B2 - Application number: 18/028,122 - Filed: 2020-09-27 - Published: 2023-10-12 - Granted: 2024-10-08 - Earliest claimed: 2020-09-25 - Assignees: Hangzhou Xinghe Technology Co., Ltd. - Applicants: Hangzhou Xinghe Technology Co., Ltd. - Inventors: Linping Li; Jinghao Sheng; Zhou Jiang - Web page: https://patentgrep.com/patent/US12113503B2 ## CPC - H03H 3/02: for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) - H03H 9/02118: {of lateral leakage between adjacent resonators} - H03H 9/02125: {of parasitic elements} - H03H 9/175: {Acoustic mirrors} - H03H 9/13: for networks consisting of piezoelectric or electrostrictive materials (for networks using surface acoustic waves H03H9/145) - H03H 2003/021: {the resonators or networks being of the air-gap type} - H03H 2003/025: {the resonators or networks comprising an acoustic mirror} - H03H 2003/028: {for obtaining desired values of other parameters} - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract A manufacturing process for a bulk acoustic resonator, comprising: making an acoustic mirror on a substrate; making a bottom electrode layer for covering the acoustic mirror on the substrate; performing chemical treatment on a peripheral part of the bottom electrode layer to form a modified layer, which surrounds the bottom electrode layer; making a piezoelectric layer on the bottom electrode layer; and making a top electrode layer on the piezoelectric layer. A bulk acoustic resonator, comprising: a substrate, an acoustic mirror formed on the substrate, and a bottom electrode layer, a piezoelectric layer and a top electrode layer that are sequentially formed on the substrate with the acoustic mirror, chemical treatment is performed on a part of the bottom electrode layer close to an edge of the acoustic mirror to form a modified layer. Parasitic oscillation of the resonator is inhibited, and wiring of a top electrode is greatly simplified. ## Claims ### Claim 1 A manufacturing process method for a bulk acoustic resonator, comprising: step S1: making an acoustic mirror on a substrate; step S2: making, on the substrate, a bottom electrode layer for covering the acoustic mirror; step S3: performing chemical treatment on a peripheral part of the bottom electrode layer to form a modified layer, wherein the modified layer surrounds the bottom electrode layer; step S4: making a piezoelectric layer on the bottom electrode layer; and step S5: making a top electrode layer on the piezoelectric layer, wherein the modified layer is formed by performing at least local chemical treatment on the peripheral part of the bottom electrode layer. ### Claim 2 (depends on 1) The manufacturing process method according to claim 1, wherein the bottom electrode is made of a metal and/or an alloy material. ### Claim 3 (depends on 1) The manufacturing process method according to claim 1, wherein the modified layer is formed by performing total chemical treatment on the peripheral part of the bottom electrode layer. ### Claim 4 (depends on 1) The manufacturing process method according to claim 1, wherein in step S4, the piezoelectric layer at least covers the modified layer, and an amorphous crystal structure is formed above the modified layer. ### Claim 5 (depends on 1) The manufacturing process method according to claim 1, wherein the acoustic mirror comprises a cavity or a Bragg reflector structure. ### Claim 6 (depends on 1) The manufacturing process method according to claim 1, wherein the chemical treatment comprises vulcanization treatment, and the step S3 comprises: step S21: making a patterned hard mask on the bottom electrode layer to expose the bottom electrode in a to-be-vulcanized region; step S22: putting a wafer with the patterned hard mask into a reaction furnace, introducing a mixed gas composed of oxygen, nitrogen and hydrogen sulfide, wherein a temperature maintains to be within a range from 700 degrees Celsius to 800 degrees Celsius to realize vulcanization reaction; and step S23: removing the patterned hard mask. ### Claim 7 (depends on 6) The manufacturing process method according to claim 6, wherein the step S22 comprises: putting the wafer with the patterned hard mask into the reaction furnace, introducing oxygen to realize oxidation, introducing an inert gas as a carrier, and introducing sulfur powder as a precursor, wherein the temperature maintains to be within a range from 600 degrees Celsius to 700 degrees Celsius to realize the vulcanization reaction. ### Claim 8 A bulk acoustic resonator, comprising: a substrate, an acoustic mirror formed on the substrate; and a bottom electrode layer, a piezoelectric layer and a top electrode layer that are sequentially formed on the substrate with the acoustic mirror; wherein chemical treatment is performed on a part of the bottom electrode layer close to an edge of the acoustic mirror to form a modified layer, and the modified layer surrounds the bottom electrode layer, wherein at least local chemical treatment is performed on the part of the bottom electrode layer close to the edge of the acoustic mirror to form the modified layer. ### Claim 9 (depends on 8) The bulk acoustic resonator according to claim 8, wherein the piezoelectric layer is made after formation of the modified layer and at least covers the modified layer, and an amorphous crystal structure is formed above the modified layer. ### Claim 10 (depends on 8) The bulk acoustic resonator according to claim 8, wherein total chemical treatment is performed on the part of the bottom electrode layer close to the edge of the acoustic mirror to form the modified layer. ### Claim 11 (depends on 8) The bulk acoustic resonator according to claim 8, wherein a surface of the modified layer is higher than the bottom electrode layer without chemical treatment. ### Claim 12 (depends on 8) The bulk acoustic resonator according to claim 8, wherein the acoustic mirror comprises a cavity or a Bragg reflector structure. ### Claim 13 (depends on 8) The bulk acoustic resonator according to claim 8, wherein: the chemical treatment comprises vulcanization treatment; the vulcanized modified layer surrounds a peripheral part of the bottom electrode layer; and the bottom electrode is made of a metal and/or an alloy material.