公开(公告)号：EP3975273A1

公开(公告)日：2022-03-30

申请号：EP21199247.4

申请日：2021-09-27

Applicant: STMicroelectronics S.r.l.

Inventor： GIUSTI, Domenico ,  MARTINI, Irene ,  ASSANELLI, Davide ,  FERRARINI, Paolo ,  PRELINI, Carlo Luigi ,  QUAGLIA, Fabio

IPC: H01L41/08 ,  H01L41/09 ,  H01L41/319 ,  B06B1/06

Abstract: A piezoelectric microelectromechanical structure (10), provided with a piezoelectric layer structure (11) having a main extension in a horizontal plane (xy) and a variable cross-section in a plane (xz) transverse to the horizontal plane, comprises a bottom electrode (12), a piezoelectric material (14) constituted by a PZT film arranged on the bottom electrode, and a top electrode (16) arranged on the piezoelectric material, wherein the piezoelectric material has a first thickness (w1) along a vertical axis (z) at a first area (14') and a second thickness (w2) along the vertical axis (z) at a second area (14"), the second thickness being smaller than the first thickness. A corresponding manufacturing process is also disclosed.

公开(公告)号：EP3623341A1

公开(公告)日：2020-03-18

申请号：EP19196770.2

申请日：2019-09-11

Applicant: STMicroelectronics S.r.l.

Inventor： COSTANTINI, Sonia ,  ASSANELLI, Davide ,  BORTOLOTTI, Aldo Luigi ,  VIMERCATI, Michele ,  VARISCO, Igor

IPC: B81C1/00

Abstract: A manufacturing process comprising the steps of: forming a bottom semiconductor region (130) including a main sub-region (131), which extends through a bottom dielectric region (112_bot, 114_bot) that coats a semiconductor wafer (100), and a secondary sub-region (134), which coats the bottom dielectric region and surrounds the main sub-region; forming a first top cavity (140) and a second top cavity (142) through the wafer, delimiting a fixed body (145, 146, 148, 154, 155) and a patterned structure (151, 152, 153) that includes a central portion (151), which contacts the main sub-region, and deformable portions (152, 153), in contact with the bottom dielectric region; forming a bottom cavity (180) through the bottom semiconductor region, as far as the bottom dielectric region, the bottom cavity laterally delimiting a stiffening region (191) that includes the main sub-region and leaving exposed parts of the bottom dielectric region that contact the deformable portions and parts of the bottom dielectric region that delimit the first and second top cavities; and selectively removing the parts left exposed by the bottom cavity.

公开(公告)号：EP3742506A1

公开(公告)日：2020-11-25

申请号：EP20176147.5

申请日：2020-05-22

Applicant: STMicroelectronics S.r.l.

Inventor： ASSANELLI, Davide ,  MARTINI, Irene ,  VINCIGUERRA, Lorenzo ,  LAZZARI, Carla Maria ,  FERRARINI, Paolo

IPC: H01L41/29 ,  H01L41/23 ,  H01L41/047 ,  H01L41/053 ,  B41J2/14

Abstract: A method for manufacturing a piezoelectric transducer (100) is disclosed, which comprises forming a bottom electrode (34, 40) on a semiconductor body (32), forming a piezoelectric element (36) on the bottom electrode, forming a protective layer (42) having a first opening (44) through which a portion of the piezoelectric element is exposed and a second opening (45) through which a portion of the bottom electrode is exposed, forming a conductive layer on the protective layer and within the first and second openings, and patterning the conductive layer to contextually form a top electrode (48) in electrical contact with the piezoelectric element at the first opening, a first biasing stripe (51) in electrical contact with the top electrode, and a second biasing stripe (52) in electrical contact with the bottom electrode at the second opening. A passivation layer (56) and metal contacts (61, 62) may be formed thereafter.