Process for manufacturing high-sensitivity capacitive and resonant integrated sensors, particularly accelerometers and gyroscopes, and sensors made therefrom
AssigneeSTMicroelectronics S.r.l.
InventorsBenedetto Vigna, Paolo Ferrari, Marco Ferrera, Pietro Montanini
Life of this patent
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Abstract
A sensor having high sensitivity is formed using a suspended structure with a high-density tungsten core. To manufacture it, a sacrificial layer of silicon oxide, a polycrystal silicon layer, a tungsten layer and a silicon carbide layer are deposited in succession over a single crystal silicon body. The suspended structure is defined by selectively removing the silicon carbide, tungsten and polycrystal silicon layers. Then spacers of silicon carbide are formed which cover the uncovered ends of the tungsten layer, and the sacrificial layer is then removed.
Claims9
A process for manufacturing integrated sensors, particularly accelerometers and gyroscopes, comprising the steps of forming a temporary support region of sacrificial material over a semiconductor material body and a suspended structure including a tungsten region over said temporary support region and then removing said temporary support region, wherein said step of forming a suspended structure comprises the steps of:
- depositing a polycrystalline silicon layer over said temporary support region;
- depositing a tungsten layer over said polycrystalline silicon layer;
- depositing a first silicon carbide layer over said tungsten layer;
- defining said suspended structure by selectively removing said silicon carbide, tungsten and polycrystalline silicon layers;
- and
- forming spacer elements of silicon carbide laterally with respect to uncovered ends of said tungsten layer.
A method for producing a sensor, comprising:
- forming a sacrificial support layer on a semiconductor substrate;
- forming a suspended structure on the sacrificial support layer, the suspended structure having a tungsten region and coupled by at least one anchorage region to the semiconductor substrate;
- and
- removing the sacrificial layer, wherein the step of forming a suspended structure layer comprises:
- forming a polysilicon layer over the sacrificial support layer;
- forming a tungsten layer over the polysilicon layer;
- forming a protection layer over the tungsten layer;
- selectively removing portions of the protective, tungsten and polysilicon layers to form a desired pattern;
- and
- covering exposed portions of the tungsten layer with spacer elements.
A method for producing a sensor, comprising:
- forming a sacrificial support layer on a semiconductor substrate;
- forming a suspended structure on the sacrificial support layer, the suspended structure having a tungsten region and coupled by at least one anchorage region to the semiconductor substrate;
- and
- removing the sacrificial layer,
- forming a first adhesive layer on the sacrificial support layer before forming the polysilicon layer;
- and
- forming a second adhesive layer on the tungsten layer before forming the protective layer.
Dependencies are inferred from the claim text.