Abstract: Acoustic sensor and manufacturing method. The acoustic sensor includes: a base including a first silicon layer, a first oxide layer and a second silicon layer stacked, and a back cavity; a second oxide layer formed on the base; a piezoelectric unit formed on the second oxide layer and including a first electrode layer, a piezoelectric layer and a second electrode layer stacked; a first slit formed at a middle portion of the second electrode layer and passing the second electrode layer, the piezoelectric layer and the first electrode layer; a second slit formed at a middle portion of the second silicon layer and passing the second silicon layer and the second oxide layer; an additional membrane filled in the first slit and not filled in the second slit. The SPL and structural reliability are effectively improved, and the material type is not limited by dry film type materials.

Abstract: An acoustic transducer includes: substrate including first silicon layer, first oxide layer and second silicon layer, back chamber is formed therethrough; second oxide layer on the substrate; piezoelectric unit on the second oxide layer and including first electrode layer, piezoelectric layer and second electrode layer; slit and opening formed in the second electrode layer; metal pad stacked on the first electrode layer at the opening; and additional film layer including first, second and third parts, the first part is in the slit, side wall and bottom wall of the first part form groove, and through slot is formed in the third part to expose metal pad.

Abstract: An acoustic transducer includes: substrate including first silicon layer, first oxide layer and second silicon layer, back chamber is formed therethrough; second oxide layer on the substrate; piezoelectric unit on the second oxide layer and including first electrode layer, piezoelectric layer and second electrode layer; slit and opening formed in the second electrode layer; metal pad stacked on the first electrode layer at the opening; and additional film layer including first and second parts, the first part is lay on the second electrode layer and covers the slit, and the second part is lay on the metal pad, through slot is formed penetrating the second part to expose the metal pad. Compared with the related art, additional film layer is formed by vapor deposition, and the piezoelectric unit can vibrate with maximum displacement and lowest restriction, thereby effectively improving SPL and structural reliability, which is suitable for larger acoustic transducers.

Abstract: An acoustic transducer includes: substrate including first silicon layer, first oxide layer and second silicon layer, back chamber is formed therethrough; second oxide layer on the substrate; piezoelectric unit on the second oxide layer and including first electrode layer, piezoelectric layer and second electrode layer; slit and opening formed in the second electrode layer; metal pad stacked on the first electrode layer at the opening; and additional film layer including first and second parts, the first part is lay on the second electrode layer and covers the slit, and the second part is lay on the metal pad, through slot is formed penetrating the second part to expose the metal pad. Compared with the related art, additional film layer is formed by vapor deposition, and the piezoelectric unit can vibrate with maximum displacement and lowest restriction, thereby effectively improving SPL and structural reliability, which is suitable for larger acoustic transducers.

Abstract: An acoustic transducer includes: substrate including first silicon layer, first oxide layer and second silicon layer, back chamber is formed therethrough; second oxide layer on the substrate; piezoelectric unit on the second oxide layer and including first electrode layer, piezoelectric layer and second electrode layer; slit and opening formed in the second electrode layer; metal pad stacked on the first electrode layer at the opening; and additional film layer including first, second and third parts, the first part is in the slit, side wall and bottom wall of the first part form groove, and through slot is formed in the third part to expose metal pad. Compared with the related art, additional film layer is formed by vapor deposition, and the piezoelectric unit can vibrate with maximum displacement and lowest restriction, thereby effectively improving SPL and structural reliability, which is suitable for larger acoustic transducers.

Abstract: Provided is a method for manufacturing a MEMS acoustic sensor. A structural layer and a piezoelectric material layer are stacked on the substrate. Photolithography modeling is performed on the piezoelectric material layer and the structural layer. A polymer layer is stacked on the piezoelectric material layer. The substrate is etched to form a cavity. A first part of a jig is stacked on the polymer layer. The jig, the substrate, the piezoelectric material layer, and the polymer layer are heated. Air is introduced into the cavity and a pressure inside the cavity is controlled. An atmospheric pressure load of the air is maintained and the air is cooled. The pressure inside the cavity is stopped to be controlled and the pressure inside the cavity is reduced, the jig is disassembled, and a wafer is cut to obtain the MEMS acoustic sensor, to effectively improve the accuracy and reliability in processing.