Microelectronic mechanical system structure forming method

Abstract

The invention discloses a microelectronic mechanical system structure forming method, which comprises the following steps: providing a substrate; depositing polycrystalline silicon on the substrate; treating the polycrystalline silicon, so that the polycrystalline silicon is transformed into porous polycrystalline silicon, wherein the porous polycrystalline silicon is used as a sacrificial layer; imaging the porous polycrystalline silicon to form a sacrificial layer pattern; depositing a structure layer on the imaged porous polycrystalline silicon; and releasing the porous polycrystalline silicon sacrificial layer. The porous polycrystalline silicon is adopted as the sacrificial layer; and the sacrificial layer is in a pore form so that the removal rate of the sacrificial layer is improved. In addition, the porous polycrystalline silicon sacrificial layer can be released by adopting xenon difluoride; and a production product is in a gaseous state at room temperature and atmospheric pressure, so that the adhesion phenomenon is avoided; and the reliability of microelectronic mechanical system structure formation is improved.

Description

technical field [0001] The invention relates to the technical field of micro-electro-mechanical systems, in particular to a method for forming a micro-electro-mechanical system structure. Background technique [0002] With the rapid development of modern microelectronics technology, a new technology, Micro-Electro-Mechanical-System (MEMS, Micro-Electro-Mechanical-System) is emerging. MEMS technology integrates microelectronics technology and precision machining technology to realize the integration of microelectronics and machinery. MEMS technology has the advantages of miniaturization, stable performance, integration, and low power consumption, so it has begun to be widely used in many fields. MEMS structures, such as suspension bridge structures, cavity structures, etc., are widely used structures in the MEMS field, which are formed using a sacrificial layer release process. The process includes depositing a sacrificial oxide layer over the substrate, patterning the sacr...

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Problems solved by technology

However, since water is produced during the etching process, and water will accelerate the etching reaction, too much water residue will cause the etching rate to be too fast and difficult to control, increasing the unevenness of etching, so ethanol (water-absorbing agent) must be used ) takes water away, and the water is taken away, which will cause the etch rate to decrease, and the water produced may still make the movable structure in the MEMS device stick

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