Chips for beam-film integrated arrangement resonant beam pressure sensing device and manufacturing method thereof

Abstract

The invention discloses a beam- film integrated arrangement resonance beam pressure transducer chip and manufacturing method thereof, characterized by that, a resonant beam is made on the face side of a single silicon chip, and a pressure responsive film is made on the opposite side, wherein the resonant beam is supported by two peninsula type arrangements and accomplished by porous silicon sacrificing layer process, and low stress thick silicon nitride is selected as the making material. The invention not only simplifies the making process of the micro resonant type pressure transducer, but also increases the pressure sensitivity.

Description

technical field [0001] The invention relates to a method for manufacturing a microstructure sensor, in particular to a method for manufacturing a resonant pressure sensor chip with a beam-membrane integrated structure. Background technique [0002] Micromechanical resonant pressure sensor is known as a new generation of pressure sensor because of its high precision, good stability, small size, and easy mass production. Another typical application later. In order to isolate the medium to be measured and increase the pressure sensitivity, the microresonant pressure sensor usually does not directly reflect the change of pressure, that is, the external pressure to be measured does not directly act on the resonator, but indirectly changes the stiffness of the resonator through the pressure film. Thereby changing the resonant frequency belongs to the principle of secondary sensitivity. There are two types of manufacturing methods, one is beam-membrane split, which requires two s...

AI Technical Summary

Problems solved by technology

There are two types of manufacturing methods, one is beam-membrane split, which requires two silicon wafers to be combined into a whole through thinning and bonding processes. The disadvantage is that bonding is involved, the process is complicated, and the yield is not high; the other type of application It shows that micro-mechanical technology completes the fabrication of the beam membrane on a single silicon chip, and the sacrificial layer technology is often used to release the resonant beam. The sacrificial layer can be silicon dioxide, polysilicon, porous silicon, etc., and the porous silicon is relatively easy to manufacture and remove, and the thickness Can reach hundreds of microns, and has received widespread attention

There is a contradiction in the selection of the thickness of the sacrificial layer. If the sacrificial layer is too thin, it will be difficult to release the resonant beam by lateral undercutting. There is also a phenomenon of adhesion, that is, the beam is stuck to the underlying substrate layer, which affects the vibration of the beam.

And if the sacrificial layer is too thick, the thickness of the pressure film cannot be very small, at least greater than the thickness of the sacrificial layer, which limits the improvement of sensor sensitivity

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