Abstract: A process for manufacturing a micromechanical structure envisages: forming a buried cavity within a body of semiconductor material, separated from a top surface of the body by a first surface layer; and forming an access duct for fluid communication between the buried cavity and an external environment. The method envisages: forming an etching mask on the top surface at a first access area; forming a second surface layer on the top surface and on the etching mask; carrying out an etch such as to remove, in a position corresponding to the first access area, a portion of the second surface layer, and an underlying portion of the first surface layer not covered by the etching mask until the buried cavity is reached, thus forming both the first access duct and a filter element, set between the first access duct and the same buried cavity.

Abstract: A MEMS acoustic transducer provided with a substrate having cavity, and a membrane suspended above the cavity and fixed peripherally to the substrate, with the possibility of oscillation, through at least one membrane anchorage. The membrane comprises at least one spring arranged in the proximity of the anchorage and facing it, and is designed to act in tension or compression in a direction lying in the same plane as said membrane.

Abstract: A multilayer structure includes: a microfluidic circuit, delimited at least in part by a first sealing structure; a fluid-tight chamber delimited in part by a second sealing structure and in part by the first sealing structure, which is arranged in the fluid-tight chamber and is configured to provide a signal indicative of a leakage between the microfluidic circuit and the fluid-tight chamber.

Abstract: A micromechanical structure for a MEMS capacitive acoustic transducer, has: a substrate of semiconductor material; a rigid electrode, at least in part of conductive material, coupled to the substrate; a membrane, at least in part of conductive material, facing the rigid electrode and coupled to the substrate, which undergoes deformation in the presence of incident acoustic pressure waves and is arranged between the substrate and the rigid electrode and has a first surface and a second surface, in fluid communication, respectively, with a first chamber and a second chamber, the first chamber being delimited at least in part by a first wall portion and by a second wall portion formed by the substrate, and the second chamber being delimited at least in part by the rigid electrode; and a stopper element, connected between the first and second wall portions for limiting the deformations of the membrane. At least one electrode-anchorage element couples the rigid electrode to the stopper element.

Abstract: An assembly of a MEMS sensor device envisages: a first die, integrating a micromechanical detection structure and having an external main face; a second die, integrating an electronic circuit operatively coupled to the micromechanical detection structure, electrically and mechanically coupled to the first die and having a respective external main face. Both of the external main faces of the first die and of the second die are set in direct contact with an environment external to the assembly, without interposition of a package.

Abstract: A micromechanical structure for a MEMS capacitive acoustic transducer, has: a substrate made of semiconductor material, having a front surface lying in a horizontal plane; a membrane, coupled to the substrate and designed to undergo deformation in the presence of incident acoustic-pressure waves; a fixed electrode, which is rigid with respect to the acoustic-pressure waves and is coupled to the substrate by means of an anchorage structure, in a suspended position facing the membrane to form a detection capacitor. The anchorage structure has at least one pillar element, which is at least in part distinct from the fixed electrode and supports the fixed electrode in a position parallel to the horizontal plane.

Abstract: A microelectromechanical sensing structure for a capacitive acoustic transducer, including: a semiconductor substrate; a rigid electrode; and a membrane set between the substrate and the rigid electrode, the membrane having a first surface and a second surface, which are in fluid communication, respectively, with a first chamber and a second chamber, respectively, the first chamber being delimited at least in part by a first wall portion and a second wall portion formed at least in part by the substrate, the second chamber being delimited at least in part by the rigid electrode, the membrane being moreover designed to undergo deformation following upon incidence of pressure waves and facing the rigid electrode so as to form a sensing capacitor having a capacitance that varies as a function of the deformation of the membrane. The structure moreover includes a beam, which is connected to the first and second wall portions and is designed to limit the oscillations of the membrane.

Abstract: A method for manufacturing a protective layer for protecting an intermediate structural layer against etching with hydrofluoric acid, the intermediate structural layer being made of a material that can be etched or damaged by hydrofluoric acid, the method comprising the steps of: forming a first layer of aluminium oxide, by atomic layer deposition, on the intermediate structural layer; performing a thermal crystallization process on the first layer of aluminium oxide, forming a first intermediate protective layer; forming a second layer of aluminium oxide, by atomic layer deposition, above the first intermediate protective layer; and performing a thermal crystallization process on the second layer of aluminium oxide, forming a second intermediate protective layer and thereby completing the formation of the protective layer. The method for forming the protective layer can be used, for example, during the manufacturing steps of an inertial sensor such as a gyroscope or an accelerometer.

Abstract: A process for manufacturing a micromechanical structure envisages: forming a buried cavity within a body of semiconductor material, separated from a top surface of the body by a first surface layer; and forming an access duct for fluid communication between the buried cavity and an external environment. The method envisages: forming an etching mask on the top surface at a first access area; forming a second surface layer on the top surface and on the etching mask; carrying out an etch such as to remove, in a position corresponding to the first access area, a portion of the second surface layer, and an underlying portion of the first surface layer not covered by the etching mask until the buried cavity is reached, thus forming both the first access duct and a filter element, set between the first access duct and the same buried cavity.

Abstract: A multilayer structure includes: a microfluidic circuit, delimited at least in part by a first sealing structure; a fluid-tight chamber delimited in part by a second sealing structure and in part by the first sealing structure, which is arranged in the fluid-tight chamber and is configured to provide a signal indicative of a leakage between the microfluidic circuit and the fluid-tight chamber.

Abstract: A process for manufacturing a micromechanical structure envisages: forming a buried cavity within a body of semiconductor material, separated from a top surface of the body by a first surface layer; and forming an access duct for fluid communication between the buried cavity and an external environment. The method envisages: forming an etching mask on the top surface at a first access area; forming a second surface layer on the top surface and on the etching mask; carrying out an etch such as to remove, in a position corresponding to the first access area, a portion of the second surface layer, and an underlying portion of the first surface layer not covered by the etching mask until the buried cavity is reached, thus forming both the first access duct and a filter element, set between the first access duct and the same buried cavity.

Abstract: A MEMS acoustic transducer provided with a substrate having cavity, and a membrane suspended above the cavity and fixed peripherally to the substrate, with the possibility of oscillation, through at least one membrane anchorage. The membrane comprises at least one spring arranged in the proximity of the anchorage and facing it, and is designed to act in tension or compression in a direction lying in the same plane as said membrane.