Method and device of mems process control monitoring and packaged mems with different cavity pressures

The device of claim 11 wherein an initial gas pressure of the first MEMS cavity and an initial gas pressure of the second MEMS cavity are substantially similar.

The device of claim 11 wherein a volume of the first MEMS cavity is different from a volume of the second MEMS cavity.

The device of claim 11

• wherein the first MEMS device comprises a gyroscope;
• and
• wherein the second MEMS device comprises an accelerometer.

The device of claim 11 wherein a volume of the first lower cavity is substantially similar to a volume of the second lower cavity.

The device of claim 11 wherein a volume of the second cap region is less than a volume of the first cap region.

The device of claim 16 wherein a depth of the second cap region is less than a depth of the first cap region.

The device of claim 11 wherein the capping structure comprises:

• a capping substrate having a surface;
• a dielectric layer disposed above a surface of the capping structure, wherein the plurality of cap regions are etched within the dielectric layer to expose portions of the surface of the capping substrate and to form the first cap region and the second cap region.

The device of claim 11 wherein the capping structure comprises:

• a capping structure having a surface;
• a dielectric layer disposed above a surface of the capping substrate, wherein the first cap region is etched within the dielectric layer to expose portions of the surface of the capping substrate, and wherein the second cap region does not expose portions of the surface of the capping substrate.

The device of claim 11 further comprising a wafer-level bonding material disposed between the capping structure and the dielectric material layer.

The method of claim 21 wherein an initial gas pressure of the lower volumetric cavity and an initial gas pressure of the upper volumetric cavity are substantially similar.

The method of claim 21 further comprising forming a plurality of displacement sensors adjacent to the membrane cover, wherein the plurality of displacement sensors are configured to determine a displacement of the membrane cover towards the upper volumetric cavity or towards the lower volumetric cavity.

The method of claim 23 wherein the plurality of displacement sensors comprise capacitors.

The method of claim 21 further comprising:

• prior to the forming of the membrane cover, forming sidewall structures upon the semiconductor substrate;
• wherein the sidewall structures enable definition of the lower volumetric cavity.

The method of claim 21 further comprising:

• forming a capping structure from another semiconductor substrate, wherein the capping structure comprises a plurality of sidewall structures upon the other semiconductor substrate, wherein the sidewall structures enable definition of the upper volumetric cavity.

The method of claim 21 wherein the forming of the membrane cover comprises forming the membrane cover upon a portion of the semiconductor substrate within a first low pressure environment.

The method of claim 27

• wherein the coupling of the capping structure comprises coupling the capping structure to the membrane cover within a second low pressure environment;
• and
• wherein the first low pressure environment and the second low pressure environment are substantially similar.

The method of claim 21 wherein the upper volumetric cavity and the lower volumetric cavity have dissimilar volumes.

A method for monitoring MEMS device fabrication processes comprising:

• receiving a semiconductor substrate having a plurality of CMOS devices formed thereon, wherein the semiconductor substrate includes an upper surface, wherein the upper surface of the semiconductor substrate is associated with an outgassing characteristic, wherein a membrane cover is formed 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 bottom volumetric cavity, and wherein a capping structure is coupled to the membrane cover at a bonding interface, wherein the bonding interface is associated with a leakage characteristic, 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, and wherein the upper volumetric cavity and the lower volumetric cavity are separated by the membrane cover.

The method of claim 31 wherein an initial gas pressure of the lower volumetric cavity and an initial gas pressure of the upper volumetric cavity are substantially similar.

The method of claim 31 wherein a change in pressure in the upper volumetric cavity with respect to changes in pressure in the lower volumetric cavity are determined by a plurality of displacement sensors adjacent to the membrane cover.

The method of claim 31 wherein the semiconductor substrate comprises sidewall structures, and wherein the sidewall structures enable definition of the lower volumetric cavity.

The method of claim 31 wherein the capping structure comprises a plurality of sidewall structures, wherein the plurality of sidewall structures enable definition of the upper volumetric cavity.

The method of claim 31 wherein the upper volumetric cavity is initially associated with a first low pressure environment.

The method of claim 36

• wherein the lower volumetric cavity is initially associated with a second low pressure environment;
• and
• wherein the first low pressure environment and the second low pressure environment are substantially similar.

The method of claim 36 wherein the first low pressure environment is approximately a vacuum.

The method of claim 31 wherein the upper volumetric cavity and the lower volumetric cavity have dissimilar volumes.

The method of claim 31 further comprising reporting a change in pressure, wherein the reporting of change in pressure comprises outputting a change in capacitance value.