Method for eliminating adhesion phenomenon of suspended structure of micro-electromechanical system (MEMS)

Abstract

The invention provides a method for eliminating the adhesion phenomenon of a suspended structure of a micro-electromechanical system (MEMS). The method is characterized by temperature control: bonding a package layer on the bottom of a chip to form a bonding body, wherein, the thermal expansion coefficient of the package layer is more than that of the chip; and temperature reduction range control: reducing the temperature of the bonding body to room temperature or below room temperature. In the method, the thermal expansion coefficient of the package layer is 5.6*10<-6>-28*10<-6> / DEG C, the adopted material is FR4 (an epoxy glass cloth laminated sheet) or Al-2O3, and the thickness of the material is 50-1000 mu m. In the method, the adhesion phenomenon of the suspended structure of the MEMS can be eliminated only by controlling the size of temperature and tensile stress with a common bonder, therefore, the method has the advantages of simple process, low equipment requirements, strong controllability and capability of realizing mass production.

Description

technical field [0001] The invention relates to a method for solving the adhesion of a suspended structure in a microelectromechanical system by using tensile stress, and belongs to the technical field of manufacturing new semiconductor devices. Background technique [0002] Micro-electro-mechanical system (MEMS) technology is based on micro-electronic technology and materials to manufacture micro-movable structures to realize the sensing, execution and energy supply functions of multi-energy domains in the microscopic world. At present, there are usually two processing methods for conventional MEMS movable devices. Types, surface micromachining technology and bulk micromachining technology. The former releases the movable structure by depositing multiple layers of thin films on the device substrate, and then etching one of the thin films (sacrifice layer). The latter obtains the movable structure by direct photolithography and etching the whole material. Regardless of the...

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Problems solved by technology

Due to the small size of the suspended structure in MEMS, the magnetic field strength required by this method is relatively high, and it cannot solve the adhesion problem of single-ended suspended structures such as cantilever beams, so the application area is limited

(2) Laser irradiation method: using laser energy to heat the microstructure, because the materials of the beam and the substrate are different, their thermal expansion coefficients are different, which can generate tensile stress to release the beam from the substrate ， Poor controllability and limited range of application

And the side irradiated by the laser will produce thermal damage

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