Method for manufacturing an electroacoustic transducer comprising: - a frame; - an element moveable with respect to the frame, the moveable element comprising a membrane and a structure for rigidifying the membrane; - a first transmission arm, the moveable element being coupled to an end of the first transmission arm; method comprising the following steps: - providing a stack successively comprising a substrate, a first sacrificial layer and a first structural layer; - forming a second sacrificial layer on the first structural layer, the second sacrificial layer comprising disjointed first and second portions (24a, 24b); - forming a second structural layer on the first structural layer and the second sacrificial layer; - etching the second structural layer so as to expose the first portion of the second sacrificial layer and to delimit the rigidification structure of the moveable element, the second portion of the second sacrificial layer being encapsulated by the rigidification structure; - etching the first structural layer to the first sacrificial layer so as to delimit the membrane of the moveable element; - etching the first portion of the second sacrificial layer so as to expose a first face of the membrane and to etch a portion of the first sacrificial layer, thereby forming a cavity which extends under the rigidification structure; - etching the substrate so as to delimit the first transmission arm and to release at least partially the moveable element while opening into the cavity, the first sacrificial layer and the second portion of the second sacrificial layer serving as stop layer to the etching; - etching the first sacrificial layer so as to expose a second opposite face of the membrane. - a frame; - an element moveable with respect to the frame, the moveable element comprising a membrane and a structure for rigidifying the membrane; - a first transmission arm, the moveable element being coupled to an end of the first transmission arm; - providing a stack successively comprising a substrate, a first sacrificial layer and a first structural layer; - forming a second sacrificial layer on the first structural layer, the second sacrificial layer comprising disjointed first and second portions (24a, 24b); - forming a second structural layer on the first structural layer and the second sacrificial layer; - etching the second structural layer so as to expose the first portion of the second sacrificial layer and to delimit the rigidification structure of the moveable element, the second portion of the second sacrificial layer being encapsulated by the rigidification structure; - etching the first structural layer to the first sacrificial layer so as to delimit the membrane of the moveable element; - etching the first portion of the second sacrificial layer so as to expose a first face of the membrane and to etch a portion of the first sacrificial layer, thereby forming a cavity which extends under the rigidification structure; - etching the substrate so as to delimit the first transmission arm and to release at least partially the moveable element while opening into the cavity, the first sacrificial layer and the second portion of the second sacrificial layer serving as stop layer to the etching; - etching the first sacrificial layer so as to expose a second opposite face of the membrane.