US 12,486,162 B2
Method for manufacturing a capacitive pressure sensor and capacitive pressure sensor
Paolo Ferrari, Gallarate (IT); Flavio Francesco Villa, Milan (IT); Roberto Campedelli, Novate Milanese (IT); Luca Lamagna, Cassina de' Pecchi (IT); Enri Duqi, Milan (IT); Mikel Azpeitia Urquia, Milan (IT); Silvia Nicoli, Casatenovo (IT); and Maria Carolina Turi, Milan (IT)
Assigned to STMICROELECTRONICS S.r.l., Agrate Brianza (IT)
Filed by STMICROELECTRONICS S.r.l., Agrate Brianza (IT)
Filed on Aug. 23, 2022, as Appl. No. 17/821,717.
Claims priority of application No. 102021000022505 (IT), filed on Aug. 30, 2021.
Prior Publication US 2023/0064114 A1, Mar. 2, 2023
Int. Cl. B81C 1/00 (2006.01); G01L 9/00 (2006.01)
CPC B81C 1/00285 (2013.01) [G01L 9/0073 (2013.01); B81B 2201/0264 (2013.01)] 25 Claims
OG exemplary drawing
 
1. A method for manufacturing a micro-electro-mechanical device, the method comprising:
forming, on a substrate, a first protection layer impermeable to an etching chemical solution;
forming, on the first protection layer, a sacrificial layer of a material configured to be removed through said etching chemical solution;
forming, on the sacrificial layer, a second protection layer impermeable to said etching chemical solution;
exposing a sacrificial portion of the sacrificial layer by selectively removing a portion of the second protection layer;
forming, on the second protection layer and on the exposed sacrificial portion, a first structural laver, a portion of the first structural layer on the second protection layer being spaced from the sacrificial layer by the second protection layer:
exposing a plurality of portions of the sacrificial portion by selectively removing portions of the first structural laver:
forming, on the first structural layer and on the exposed plurality of portions of the sacrificial portion, a first membrane layer of a porous material, which is permeable to said etching chemical solution, a portion of the first membrane layer on the portion of the first structural layer being spaced from the second protection layer by the portion of the first structural layer,
forming a cavity by removing the sacrificial portion through the first membrane layer using said etching chemical solution; and
sealing pores of the first membrane layer by forming a second membrane layer on the first membrane layer.