Method for manufacturing a MEMS device by first hybrid bonding a CMOS wafer to a MEMS wafer

A method for packaging a microelectromechanical system (MEMS), the method comprising:

• forming a first metallization structure over a first wafer, wherein the first metallization structure comprises a first metal contact pad;
• forming a second metallization structure over a second wafer, wherein the second metallization structure comprises a sacrificial oxide layer and a second metal contact pad;
• hybrid bonding the first metallization structure to the second metallization structure;
• after the first metallization structure and second metallization structure are bonded together, reducing a thickness of the second wafer;
• after reducing the thickness of the second wafer, patterning and etching the second wafer to form a MEMS element over the sacrificial oxide layer;
• and
• after the second wafer is patterned and etched to form the MEMS element, etching the sacrificial oxide layer, wherein etching the sacrificial oxide layer allows the MEMS element to move freely about an axis.

A method for packaging a microelectromechanical system (MEMS), the method comprising:

• forming a first metallization structure over a first wafer, wherein the first metallization structure comprises a first sacrificial oxide layer and a first metal contact pad;
• forming a second metallization structure over a second wafer, wherein the second metallization structure comprises a second sacrificial oxide layer and a second metal contact pad;
• hybrid bonding the first metallization structure to the second metallization structure to form a first integrated circuit (IC), wherein the first IC comprises:
• metal-to-metal bonds between the first metal contact pad and the second metal contact pad, wherein the first metal contact pad has a first outermost sidewall that is offset from a first outermost sidewall of the second metal contact pad along a first axis;
• non-metal-to-non-metal bonds between the first sacrificial oxide layer and the second sacrificial oxide layer, wherein the second sacrificial oxide layer has a bottommost surface disposed between an uppermost surface of the first metal contact pad and an uppermost surface of the second wafer;
• and
• after the first IC is formed, removing the first sacrificial oxide layer and the second sacrificial oxide layer to form a movable MEMS element over an opening, wherein outermost sidewalls of the movable MEMS element are disposed between outermost sidewalls of the opening.