A kind of mems sensor and its manufacturing method, wafer module

Abstract

The present application relates to a MEMS sensor, a manufacturing method thereof, and a wafer module. The manufacturing method of the MEMS sensor includes: providing first and second bodies; the first body is provided with a first welding ring, and the second body is provided with a second welding ring corresponding to the first welding ring; Solder is provided on the top surface of at least one of them; the solder includes a first solder with a first melting point and a second solder with a second melting point, and a notch is formed at the second solder; the second melting point is higher than the first melting point; The first and second main bodies are arranged correspondingly, and the first and second welding rings are corresponding; heating makes the first and second solders melt in sequence and fuse together to form a closed annular first welding layer, and the first and second welding rings are welded together. A MEMS accommodating cavity is formed; the notch is sealed when the second solder is melted. In the above method, gas can always flow out from the notch before the notch is sealed, which is beneficial to improve the vacuum degree of the MEMS accommodating cavity after sealing and welding.

Description

technical field [0001] The present application relates to the technical field of semiconductor devices, and in particular, to a MEMS sensor, a manufacturing method thereof, and a wafer module. Background technique [0002] Hermetic packaging is a common packaging form in the MEMS field. MEMS devices such as acceleration sensors, pressure sensors, and angular velocity sensors have movable parts inside, and it is necessary to provide air-tight cavities for movable parts to ensure that the movable parts have less damping and static friction inside the cavity. MEMS devices such as uncooled infrared focal plane detectors have microbolometers inside, which require a certain degree of vacuum to ensure a small thermal radiation heat loss. When the air pressure inside the cavity rises to the point where the vacuum degree exceeds the set standard, the sensitivity of the device will decrease below the standard value, causing the device to fail. Therefore, vacuum packaging quality is ...

AI Technical Summary

Problems solved by technology

Non-evaporable getters have different selective absorption ratios for different gases, usually for metal degassing such as hydrogen, and gases in the atmosphere such as nitrogen, oxygen, and carbon dioxide have higher selective absorption ratios; but for complex degassing of packaging materials, Such as ethylene, carbon tetrafluoride, methane, etc., the selective absorption is relatively low, resulting in poor vacuum inside the cavity

Images