Miniature piezoelectric vibration energy collector and manufacturing method thereof

Abstract

The invention designs a structure of a novel MEMS piezoelectric vibration energy collector and a manufacturing method of the novel MEMS piezoelectric vibration energy collector. According to the structure, the novel MEMS piezoelectric vibration energy collector comprises a dually-polished substrate and double substrate protecting layers. According to the manufacturing method of the novel MEMS piezoelectric vibration energy collector, a front metal conductive layer (the bottom) is used as an output bottom electrode; a patterned conductive adhesive is manufactured on an upper metal layer; a PZT piezoelectric patch is bonded to a silicon wafer bottom electrode through the conductive adhesive; full-piece covering of a top electrode metal conductive layer (the top) is conducted; KOH is corroded through a window in the back-side substrate protecting layer, and a cantilever beam structure which mainly contains epoxy resin and does not contain Si is released; a cantilever beam-quality block structure is released through scribing. The novel MEMS piezoelectric vibration energy collector is simple in structure, easy to obtain, capable of facilitating batch production, high in sensitiveness, output level and power, wide in application range, safe and reliable.

Description

technical field [0001] The invention relates to a miniature piezoelectric vibration energy collector and a manufacturing method thereof, in particular to a miniature piezoelectric vibration energy collector based on an epoxy resin cantilever beam and a manufacturing method thereof. Background technique [0002] Micro-power supply is usually a part of passive wireless sensor network or micro-actuator. This kind of micro-sensor micro-actuator has a wide range of applications and a large demand. It requires small size and strong stability under the condition of ensuring performance. It often needs to work in Extreme, harsh environments or environments where batteries cannot be replaced at will, so micro-sensors and micro-actuators equipped with micro-power modules become quite necessary. [0003] Micro-power modules, that is, energy harvesters, are divided into piezoelectric, electromagnetic, variable capacitance and composite types. Piezoelectric has received special attentio...

AI Technical Summary

Problems solved by technology

However, there are fatal defects in AlN materials: 1) The film growth must have a crystal preferred orientation to have the piezoelectric effect, and this preferred orientation can be controlled by growth pressure, N 2 and Ar ratio, distance between substrate and target, growth temperature, sputtering power and other conditions. At the same time, there are higher requirements for AlN substrates. If the conditions are slightly deviated, the piezoelectric properties of AlN will be sharply reduced. attenuation

2) The piezoelectric coefficient and permittivity of AlN are too small, which is also a relatively low level in the entire piezoelectric material library

Under the constraints of this situation, the progress made in improving the performance of PZT materials is far from breaking through the bottleneck caused by the thickness of the PZT film.

[0007] For question 1, since the current micro-electromechanical system (MEMS) processing technology is based on silicon processing technology, it is not easy to give up the excellent performance of silicon substrates

For problem 2, a new idea has been proposed in recent years: the production technology of macroscopic PZT piezoelectric ceramic sheets is relatively mature, but the minimum thickness is several hundred microns and cannot be directly applied to micromachining technology.

There are two mainstream options: 1. Au-based metal bonding, which is adopted because of its low melting point and less impact on other processes, but the stress becomes larger after melting

Later, it was proposed to use Au to enhance the bonding layer and the elastic layer at the same time, but due to the extreme stress after its fusion, the released cantilever beam formed a self-bending shape, which greatly affected the performance of the device.

2. Conductive adhesive bonding, the conductive adhesive has a high viscosity, usually used with a dispenser or a printing plate, it is difficult to make a film on a silicon wafer, and its subsequent unprocessed steps are relatively immature

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