Silicon micromachined motion sensor and method of making
AssigneeDelco Electronics Corporation
InventorsDouglas Ray Sparks, George Qin Jiang, Dan Wesley Chilcott, Mark Billings Kearney
Life of this patent
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Abstract
A method for making and vacuum packaging a silicon micromachined motion sensor, such as a gyroscope, at the chip level. The method involves micromachining a trench-isolated sensing element in a sensing chip, and then attaching a circuit chip to enclose the sensing element. Solder bumps serve to attach the circuit chip to the sensing chip, form a hermetic seal to enable vacuum-packaging of the sensor, and electrically interconnect the sensing chip with the circuit chip. Conductive runners formed on the enclosed surface of the circuit chip serve to electrically interconnect the sensing element with its associated sensing structures.
Claims36
A motion sensor comprising:
- a sensing chip having a micromachined sensing element with an axis of rotation;
- electrodes on the sensing chip and forming an electrode pattern that circumscribes the sensing element;
- a trench in the sensing chip so as to circumscribe the sensing element and thereby physically isolate the sensing element from the electrodes;
- a first contact on the sensing chip and electrically connected to the sensing element;
- a circuit chip attached to the sensing chip so as to form an enclosure for the sensing element between the circuit chip and the sensing chip, the circuit chip having an integrated circuit;
- a second contact on the circuit chip and within the enclosure, the second contact being registered with the first contact so as to be electrically connected to the first contact;
- a third contact on the circuit chip and within the enclosure, the third contact being registered with one of the electrodes so as to be electrically connected thereto;
- and
- conductive runners on the circuit chip and electrically connecting the second and third contacts to the integrated circuit.
A motion sensor comprising:
- a sensing chip having a surface;
- an electrically-conductive micromachined sensing element comprising a post supporting the micromachined sensing element above the surface of the sensing chip, a plurality of spring members extending radially from the post, and a ring circumscribing the spring members and supported by the spring members, the micromachined sensing element having an axis of rotation through the post;
- electrodes on the sensing chip and forming an electrode pattern that circumscribes the micromachined sensing element;
- at least one trench in the sensing chip and surrounding the electrodes and the micromachined sensing element so as to physically and electrically isolate the electrodes from each other and the micromachined sensing element;
- a first contact on the sensing chip and electrically connected to the micromachined sensing element;
- a circuit chip attached to the sensing chip so as to enclose the micromachined sensing element between the circuit chip and the sensing chip, the circuit chip having an integrated circuit;
- a second contact on the circuit chip and electrically connected to the first contact;
- a third contact on the circuit chip and electrically connected to one of the electrodes;
- and
- conductive runners on the circuit chip and electrically connecting the second and third contacts to the integrated circuit.
A method for forming a motion sensor, the method comprising the steps of:
- forming in a sensing chip a micromachined sensing element having an axis of rotation, electrodes that define an electrode pattern that circumscribes the sensing element, a trench that circumscribes the sensing element and thereby physically isolates the sensing element from the electrodes, and a first contact electrically connected to the sensing element;
- forming on a circuit chip an integrated circuit, second and third contacts, and conductive runners that electrically connect the second and third contacts to the integrated circuit;
- and
- attaching the circuit chip to the sensing chip so as to enclose the sensing element and the first, second and third contacts between the circuit chip and the sensing chip, electrically connect the second contact with the first contact, and electrically connect the third contact to one of the electrodes.
Dependencies are inferred from the claim text.