Method to package multiple mems sensors and actuators at different gases and cavity pressures

A method for fabricating a multiple MEMS device comprising:

• providing a semiconductor substrate having a first MEMS device and a second MEMS device;
• providing an initial encapsulation wafer;
• patterning a masking layer on top of the initial encapsulation wafer, wherein the masking layer comprises a first opening, a second opening, and a third opening, wherein a width of the third opening is substantially smaller than a width of the first opening or a width of the second opening;
• etching the initial encapsulation wafer to form an encapsulation layer, wherein a first cavity is associated with the first opening, a second cavity is associated with the second opening, and the third opening is associated with at least one channel providing a first encapsulation environment at a first air pressure;
• encapsulating the first MEMS device within the first cavity and the second MEMS device within the second cavity, while within the first encapsulation environment, to encapsulate the first MEMS device within the first cavity at the first air pressure;
• providing a second encapsulating environment at a second air pressure, wherein the second air pressure is different from the first air pressure;
• subjecting the second MEMS device within the second cavity to the second encapsulation environment via the at least one channel;
• and
• sealing the at least one channel, while within the second encapsulation environment, to encapsulate the second MEMS device within the second cavity at the second air pressure.

A method for fabricating a multiple MEMS device comprising:

• providing a semiconductor substrate having a first MEMS device and a second MEMS device, the semiconductor substrate having a device layer, an interconnect layer or dielectric layer, and at least one channel;
• providing an encapsulation wafer comprising a first cavity and a second cavity;
• providing a first encapsulation environment at a first air pressure;
• encapsulating the first MEMS device within the first cavity and the second MEMS device within the second cavity, while within the first encapsulation environment, to encapsulate the first MEMS device within the first cavity at the first air pressure, the encapsulation wafer being bonded to the device layer;
• providing a second encapsulating environment at a second air pressure, wherein the second air pressure is different from the first air pressure;
• subjecting the second MEMS device within the second cavity to the second encapsulation environment via the at least one channel;
• and
• sealing the at least one channel, while within the second encapsulation environment, to encapsulate the second MEMS device within the second cavity at the second air pressure.