Micro hermetic sensor
First Claim
1. A sensor assembly for determining whether a hermetically sealed cavity between opposing substrate wafers in a wafer level packaged (WLP) chip is leaking, said sensor assembly comprising:
- a membrane secured to a surface of one of the wafers within the cavity so as to define a gas gap between the membrane and the one wafer; and
a resistive element deposited on the membrane, said resistive element being responsive to a current that heats the membrane so that heat dissipated by the membrane is drawn away by gas within the cavity that determines the temperature of the resistive element, which is detected.
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Accused Products
Abstract
A sensor assembly for determining whether a hermetically sealed cavity between opposing substrate wafers in a wafer level packaged (WLP) chip is leaking. The sensor assembly includes a thermal insulating layer provided within the cavity, and a heater and temperature sensor deposited on the insulation layer. The thermal insulating layer is made of a suitable dielectric that is compatible with WLP and MMIC fabrication processes and can be, for example, benzocyclobutene (BCB) or polyimide. The sensor is responsive to a current that heats the thermal insulation layer so that heat dissipated by the thermal insulation layer is drawn away by gas between the layer and the substrate that determines the temperature of the sensor, which is detected.
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Citations
20 Claims
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1. A sensor assembly for determining whether a hermetically sealed cavity between opposing substrate wafers in a wafer level packaged (WLP) chip is leaking, said sensor assembly comprising:
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a membrane secured to a surface of one of the wafers within the cavity so as to define a gas gap between the membrane and the one wafer; and a resistive element deposited on the membrane, said resistive element being responsive to a current that heats the membrane so that heat dissipated by the membrane is drawn away by gas within the cavity that determines the temperature of the resistive element, which is detected. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A sensor assembly for determining whether a hermetically sealed cavity between opposing substrate wafers in a wafer level package (WLP) chip is leaking, said sensor assembly comprising:
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a thermal insulation layer deposited on a surface of one of the wafers within the cavity; an air bridge formed to the insulation layer and defining a gap therebetween; and a resistive element formed on the insulation layer, said resistive element being responsive to a current that heats the thermal insulation layer so that heat drawn away by gas within the gap determines the temperature of the resistive element, which is detected. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A sensor assembly for determining whether a hermetically sealed cavity between opposing substrate wafers and a wafer level packaged (WLP) chip is leaking, said sensor assembly comprising:
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a thermal insulating layer provided within the cavity; and a heater and temperature sensor deposited on the insulation layer, said sensor being responsive to a current that heats the thermal insulation layer so that heat dissipated by the thermal insulation layer is drawn away by gas within the cavity that determines the temperature of the sensor, which is detected. - View Dependent Claims (19, 20)
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Specification