Method for manufacturing an integrated system including a capacitive pressure sensor and an inertial sensor, and integrated system
AssigneeSTMicroelectronics S.r.l.
InventorsPaolo FERRARI, Lorenzo CORSO, Flavio Francesco VILLA, Silvia NICOLI, Luca LAMAGNA
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Abstract
Method for manufacturing a micro-electro-mechanical system, MEMS, integrating a first MEMS device and a second MEMS device. The first MEMS device is a capacitive pressure sensor and the second MEMS device is an inertial sensor. The steps of manufacturing the first and second MEMS devices are, at least partly, shared with each other, resulting in a high degree of integration on a single die, and allowing to implement a manufacturing process with high yield and controlled costs.
Claims20
A method for manufacturing a micro-electro-mechanical system, MEMS, including a first MEMS device and a second MEMS device, comprising:
- forming, on a substrate, a first electrode of the first MEMS device;
- forming, on the first electrode, a first sacrificial layer;
- forming, on the first sacrificial layer, a protection layer impermeable to an etching chemical solution;
- selectively removing portions of the protection layer to expose a respective sacrificial portion of the first sacrificial layer;
- forming, on the sacrificial portion, a membrane layer of a porous material, which is permeable to the etching chemical solution;
- forming a cavity by removing the sacrificial portion through the membrane layer using the etching chemical solution;
- forming a first structural layer which seals pores of the membrane layer and forms, with the membrane layer, a suspended structure of the first MEMS device, the suspended structure being a second electrode capacitively coupled to the first electrode through the cavity;
- forming, above the first structural layer, a second sacrificial layer of a material which may be etched through the etching chemical solution;
- forming a second structural layer above, and in contact with, the second sacrificial layer;
- patterning the second structural layer to concurrently form movable structures of the second MEMS device and biasing structures of the first and second electrodes of the first MEMS device;
- removing selective portions of the second sacrificial layer through the etching chemical solution, making the movable structures of the second MEMS device and the suspended structure of the first MEMS device free to move according to respective degrees of freedom.
A device, comprising:
- a first MEMS device;
- a second MEMS device
- a substrate;
- a first electrode coupled to the first MEMS device extending on the substrate;
- a first layer on the first electrode;
- a protection layer, impermeable to an etching chemical solution, on the first layer;
- a membrane layer, of a porous material which is permeable to the etching chemical solution, on the protection layer;
- a cavity overlapped by the membrane layer;
- a first structural layer seals pores of the membrane layer and forms, with the membrane layer, a suspended structure of the first MEMS device, the suspended structure being a second electrode capacitively coupled to the first electrode through the cavity;
- and
- a second structural layer is on the first structural layer, and the second structural layer includes:
- moveable structures of the second MEMS device;
- and
- biasing structures of the first and second electrodes of the first MEMS device.
A device, comprising:
- a substrate including a surface;
- a plurality of layers on the first surface
- a cavity within the plurality of layers;
- a structural layer on the plurality of layers;
- a plurality of through holes extending into the structural layer and extending into the plurality of layers;
- a first MEMS device including a membrane of the plurality of layers and the structural layer overlapping the cavity;
- a second MEMS device adjacent to the first MEMS device.
Dependencies are inferred from the claim text.