Wafer level sealing methods with different vacuum levels for mems sensors

A wafer level packaging (WLP) structure, comprising:

• a MEMs work-piece including a first MEMs device, a second MEMs device and a fluid path adjacent the second MEMs device;
• a carrier work-piece disposed under the MEMs work-piece, the carrier work-piece including a carrier work-piece fluid channel adjoining the fluid path and extending downward from an upper surface of the carrier work-piece to a carrier work-piece cavity within the carrier work-piece, wherein the carrier work-piece fluid channel has a first width that is less than a second width of the carrier work-piece cavity;
• a cap work-piece bonded to an upper surface of the MEMs work-piece to create a first cavity and a second cavity between the cap and MEMs work-pieces, wherein the first cavity is in fluid communication with the first MEMs device and the second cavity is in fluid communication with both the second MEMs device and the fluid path;
• a hole in the cap work-piece that opens to the fluid path;
• and
• a sealing layer over the cap work-piece to cover the hole and seal the fluid path from an ambient environment external to the wafer package system.

A wafer level packaging (WLP) structure comprising:

• a MEMs work-piece including a first MEMs device, a second MEMs device, and a fluid path in fluid communication with the second MEMs device;
• a carrier work-piece disposed under the MEMs work-piece, the carrier work-piece including a carrier work-piece fluid channel adjoining the fluid path and extending downward from an upper surface of the carrier work-piece to a carrier workpiece cavity within the carrier work-piece, wherein the carrier workpiece fluid channel has a first width and the carrier work-piece cavity has a second width which is greater than the first width;
• a first cavity which is in fluid communication with the first MEMs device and a second cavity which is in fluid communication with the second MEMs device, wherein the first cavity retains a first pressure level and the second cavity retains a different second pressure level;
• a cap work-piece disposed over the MEMs work-piece and coupled to the MEMs workpiece through eutectic bonding;
• a hole in the cap work-piece that opens to one of the fluid paths in the MEMs work-piece;
• a sealing layer over the cap work-piece to cover the hole and seal the one of the fluid paths from an ambient environment external to the wafer package system.