Method for manufacturing suspension micro electromechanical structure

Abstract

The invention discloses a method for manufacturing a suspension micro electromechanical structure, which comprises the following steps: firstly, at least one insulation layer internally provided with a metal micro electromechanical structure is formed on the upper surface of a silicon fundus, the micro electromechanical structure comprises at least one microstructure and at least one metal sacrifice structure which are independent with each other, and the metal sacrifice structure is internally provided with metal layers and metal bolt layers connecting the metal layers; secondly, at least one blocking layer is made on the upper surface of the insulation layer; thirdly, at least one etching blocking layer is made on the lower surface of the silicon fundus; fourthly, etching is carried out to the lower surface of the silicon fundus to form a space corresponding to the inner suspension microstructure of the micro electromechanical structure; and finally, etching is carried out to the metal sacrifice structure to form the suspension of the micro electromechanical structure. The invention can effectively avoid the improper erosion of the suspension micro electromechanical structure and the surrounding insulation layer thereof, reduce the exposure rate of the suspension micro electromechanical structure, and reduce the final encapsulation cost by being integrated with common integrated circuit packaging.

Description

technical field [0001] The invention relates to a method for manufacturing a micro-electromechanical device, in particular to a method for manufacturing a suspended micro-electromechanical structure. Background technique [0002] Modern semiconductor microelectromechanical systems include various semiconductor microstructures, such as immovable probes, flow channels, and cavity structures, or some movable springs, connecting rods, gears, and other structures. Various semiconductor applications can be formed by integrating the above-mentioned different structures and related semiconductor circuits with each other. Improving the functionality of micromechanical structures through fabrication methods can improve the performance of semiconductor MEMS. [0003] At present, the production of micro-electromechanical sensors and actuator systems often requires the production of suspended structures on silicon substrates, generally using advanced semiconductor technology. Examples:...

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Problems solved by technology

[0004] Although the above-mentioned prior art can make suspended micro-electromechanical structures, it will produce the following defects: First, the prior art uses anisotropic chemical etching to remove the insulating layer by chemical reaction, but due to the micro-electromechanical After the side edge of the electromechanical structure, it is still necessary to perform isotropic chemical etching to etch a large amount of the silicon substrate, which will cause serious side etching

Second, in this prior art process, the MEMS structure is exposed to the process from the very beginning. After a long multi-layer process, the MEMS structure is often polluted and damaged, resulting in a low yield rate.

Thirdly, in this prior art, after the etching is completed, the micro-electro-mechanical structure can already operate in suspension, but the surface of the micro-electro-mechanical structure still needs to be packaged with special machinery to block the air, but since the micro-electro-mechanical structure must ensure a suspended state, it is generally Use a special mold cover on the surface of the product, and then precisely manufacture the packaging protective film that does not touch the suspended MEMS structure, which increases the cost and manufacturing complexity, and cannot be integrated with the packaging of general integrated circuits

[0005] In order to improve the problems in the above-mentioned prior art, US Patent No. 6712983B2 proposes the use of ion etching technology. Although this technology can greatly reduce the side etching phenomenon, it is also etched layer by layer from top to bottom, and the last time A large amount of silicon substrate etching work must use lateral etching technology. This improved existing technology is still too troublesome and complicated, and there will still be side etching through a large amount of etching and lateral etching of micro-electro-mechanical structures, and it cannot solve the problem of exposure of micro-electro-mechanical structures. , Difficult post-production encapsulation

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