Method and device of MEMS process control monitoring and packaged MEMS with different cavity pressures
First Claim
1. A method for forming a process control monitor comprising:
- receiving a semiconductor substrate having a plurality of CMOS devices formed thereon, wherein the semiconductor substrate includes an upper surface;
forming a membrane cover upon at least a portion of the semiconductor substrate, wherein the membrane cover includes an upper surface and a lower surface, wherein the lower surface of the membrane cover and a portion of the upper surface of the semiconductor substrate enable definition of a lower volumetric cavity;
coupling a capping structure to the membrane cover at a bonding interface on the membrane cover, wherein the capping structure includes a lower surface, wherein the upper surface of the membrane cover and lower surface of the capping structure enable definition of an upper volumetric cavity;
wherein the upper volumetric cavity and the lower volumetric cavity are separated by the membrane cover, the membrane cover is configured to make a displacement towards the lower volumetric cavity as a result of leakage from the bonding interface, and the membrane cover is configured to make a displacement towards the upper volumetric cavity as a result from outgassing from the upper surface of the semiconductor substrate; and
forming one or more displacement sensors adjacent to the membrane cover, wherein the one or more displacement sensors are configured to determine a displacement of the membrane cover towards the upper volumetric cavity or towards the lower volumetric cavity as a result of outgassing from the upper surface of the semiconductor substrate or leakage from the bonding interface.
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Accused Products
Abstract
A method for fabricating an integrated MEMS device and the resulting structure therefore. A control process monitor comprising a MEMS membrane cover can be provided within an integrated CMOS-MEMS package to monitor package leaking or outgassing. The MEMS membrane cover can separate an upper cavity region subject to leaking from a lower cavity subject to outgassing. Differential changes in pressure between these cavities can be detecting by monitoring the deflection of the membrane cover via a plurality of displacement sensors. An integrated MEMS device can be fabricated with a first and second MEMS device configured with a first and second MEMS cavity, respectively. The separate cavities can be formed via etching a capping structure to configure each cavity with a separate cavity volume. By utilizing an outgassing characteristic of a CMOS layer within the integrated MEMS device, the first and second MEMS cavities can be configured with different cavity pressures.
21 Citations
19 Claims
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1. A method for forming a process control monitor comprising:
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receiving a semiconductor substrate having a plurality of CMOS devices formed thereon, wherein the semiconductor substrate includes an upper surface; forming a membrane cover upon at least a portion of the semiconductor substrate, wherein the membrane cover includes an upper surface and a lower surface, wherein the lower surface of the membrane cover and a portion of the upper surface of the semiconductor substrate enable definition of a lower volumetric cavity; coupling a capping structure to the membrane cover at a bonding interface on the membrane cover, wherein the capping structure includes a lower surface, wherein the upper surface of the membrane cover and lower surface of the capping structure enable definition of an upper volumetric cavity; wherein the upper volumetric cavity and the lower volumetric cavity are separated by the membrane cover, the membrane cover is configured to make a displacement towards the lower volumetric cavity as a result of leakage from the bonding interface, and the membrane cover is configured to make a displacement towards the upper volumetric cavity as a result from outgassing from the upper surface of the semiconductor substrate; and forming one or more displacement sensors adjacent to the membrane cover, wherein the one or more displacement sensors are configured to determine a displacement of the membrane cover towards the upper volumetric cavity or towards the lower volumetric cavity as a result of outgassing from the upper surface of the semiconductor substrate or leakage from the bonding interface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for monitoring MEMS (Micro Electro Mechanical System) device fabrication processes comprising:
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receiving a semiconductor substrate having a plurality of CMOS devices formed thereon, wherein the semiconductor substrate includes an upper surface; forming a membrane cover upon at least a portion of the semiconductor substrate, wherein the membrane cover includes an upper surface and a lower surface, wherein the lower surface of the membrane cover and a portion of the upper surface of the semiconductor substrate enable definition of a lower volumetric cavity; and coupling a capping structure to the membrane cover at a bonding interface on the membrane cover, wherein the capping structure includes a lower surface, wherein the upper surface of the membrane cover and the lower surface of the capping structure enable definition of an upper volumetric cavity; wherein the upper volumetric cavity and the lower volumetric cavity are separated by the membrane cover, wherein the membrane cover is configured to make a displacement towards the lower volumetric cavity as a result of leakage from the bonding interface, and the membrane cover is configured to make a displacement towards the upper volumetric cavity as a result from outgassing from the upper surface of the semiconductor substrate. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification