Static charge dissipation pads for sensors
AssigneeSTMicroelectronics S.r.l.
InventorsArnaud Yves Lepert, Frederic Denis Raynal
Life of this patent
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Abstract
A structure and method for dissipating charges comprising an underlying dielectric layer disposed over capacitor plates of sensor circuitry, and a conductive path and passivation layers disposed over the underlying dielectric layer wherein the conductive pad forms an electrically conductive path over at least a portion of the plates and diffuses electrostatic charges at the surface of the integrated circuit.
Claims20
A portion of an integrated circuit, comprising:
- a plurality of conductive plates arranged within a single layer in pairs of capacitive sensing electrodes;
- an insulating layer between and over the plurality of conductive plates, wherein an upper surface of the insulating layer serves as a contact surface for a finger having a fingerprint pattern to be detected, wherein the finger forms a capacitor with each pair of capacitive sensing electrodes when placed on the contact surface;
- and
- a conductive electrostatic discharge pad disposed within the insulating layer over at least a portion of at least one capacitive sensing electrode within each pair of capacitive sensing electrodes and between the portion of the at least one capacitive sensing electrode and the contact surface.
A portion of an integrated circuit, comprising:
- a plurality of conductive plates arranged within a single layer in pairs of capacitive sensing electrodes, each pair of capacitive sensing electrodes forming a pixel sensing element;
- a protective layer including a dielectric material over and between the plurality of conductive plates, the protective layer electrically isolating the conductive plates, an upper surface of the protective layer serving as a contact surface for a finger forming a capacitor with each pair of capacitive sensing electrodes when a portion of the finger is placed on the contact surface;
- and
- a conductive path disposed within the protective layer separated from the conductive plates by a portion of the dielectric material and disposed over at least a portion of at least one capacitive sensing electrode within each pair of capacitive sensing electrodes and between the portion of the at least one capacitive sensing electrode and the contact surface, wherein the conductive path dissipates an electrostatic charge in a manner that prevents the electrostatic charge from reaching the plurality of conductive plates.
A portion of an integrated circuit for capacitively sensing a fingerprint pattern on a finger, comprising:
- an array of pairs of capacitive sensing electrodes formed within a single layer and employed for sensing the fingerprint pattern, each pair of capacitive sensing electrodes comprising:
- an inner conductive plate forming a central portion;
- and
- an outer conductive plate forming a loop around substantially all of a periphery of the central portion, the inner and outer conductive plates separated by a gap, wherein each pair of capacitive sensing electrodes forms a single capacitor with a portion of a finger when the finger is placed in proximity to the conductive plates;
- a protective layer including an insulating material between and over the conductive plates;
- and
- a conductive electrostatic discharge pad disposed within the protective layer and overlying at least a portion of at least one conductive plate within said each pair of capacitive sensing electrodes, the discharge pad separated from the conductive plates by a portion of the insulating material.
Dependencies are inferred from the claim text.