Integrated Capacitive Humidity Sensor
AssigneeFreescale Semiconductor, Inc.
InventorsQing Zhang, Mohommad Choudhuri, Gul Zeb
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Abstract
A semiconductor device composed of a capacitive humidity sensor comprised of a moisture-sensitive polymer layer electrografted to an electrically conductive metal layer situated on an CMOS substrate or a combined MEMS and CMOS substrate, and exposed within an opening through a passivation layer, packages composed of the encapsulated device, and methods of forming the capacitive humidity sensor within the semiconductor device, are provided.
Claims20
A method for forming a semiconductor device, comprising:
- forming a first electrically conductive metal layer on a surface of an IC substrate;
- electrografting a moisture-sensitive polymer layer onto the first electrically conductive metal layer;
- and
- forming a passivation layer over the substrate with the polymer layer exposed through one or more openings in the passivation layer;
- wherein the polymer layer functions as a capacitive humidity sensing element when exposed to ambient air;
- further comprising after electrografting the polymer layer,
- forming a second electrically conductive material layer over the polymer layer;
- forming a passivation layer over the second electrically conductive material layer;
- and
- forming a one or more of openings through the passivation layer and underlying second electrically conductive layer to expose the polymer layer;
- wherein the polymer layer functions as a capacitive humidity sensing element when exposed to ambient air.
(canceled)
A semiconductor device, comprising:
- a moisture-sensitive polymer layer electrografted to a first electrically conductive metal layer situated on an IC substrate, and exposed within one or more openings through a passivation layer;
- wherein the moisture-sensitive polymer layer functions as a capacitive humidity sensing element when exposed to ambient air;
- a second electrically conductive material layer over the polymer layer;
- a passivation layer over the second electrically conductive material layer;
- and
- one or more of openings through the passivation layer and underlying second electrically conductive layer configured to expose the polymer layer.
An encapsulated semiconductor device package, comprising:
- a semiconductor device, comprising a moisture-sensitive polymer layer electrografted to an electrically conductive metal layer situated on an IC substrate and exposed within one or more openings in a passivation layer;
- and
- an encapsulant surrounding the device except for the moisture-sensitive polymer layer which is exposed within said one or more openings in the passivation layer;
- wherein the moisture-sensitive polymer layer functions as a capacitive humidity sensing element when exposed to ambient air;
- a second electrically conductive material layer over the polymer layer;
- a passivation layer over the second electrically conductive material layer;
- and
- one or more of openings through the passivation layer and underlying second electrically conductive layer configured to expose the polymer layer.
Dependencies are inferred from the claim text.