Preparation method for motion sensor

Abstract

The invention relates to a preparation method for a motion sensor. The method includes: providing a base, on which a CMOS device is formed; forming a bottom electrode on the base and an MEMS substrate positioned above the bottom electrode, and forming a cavity between the bottom electrode and the MEMS substrate; etching the MEMS substrate to the bottom electrode to form a deep through hole, thereby exposing the bottom electrode; etching the top of the deep through hole to expand the key size of the deep through hole top opening; forming an insulation layer on the side wall of the deep through hole; and depositing a metal material in the deep through hole, and then conducting etching to remove the metal material deposited at the deep through hole top so as to maintain a large key size of the opening. According to the method provided by the invention, no hole is formed in the filling process, and the device yield is improved.

Description

technical field [0001] The invention relates to the field of semiconductors, and in particular, the invention relates to a method for preparing a motion sensor. Background technique [0002] With the continuous development of semiconductor technology, smartphones, integrated CMOS and micro-electromechanical systems (MEMS) devices have increasingly become the most mainstream and advanced technologies in the market for motion sensor products, and with technology updates , the development direction of this type of transmission sensor products is smaller size, high-quality electrical performance and lower loss. [0003] In the prior art, a deep reactive ion etching (DRIE) system is required most of the time to prepare the motion sensor, and reactive ion etching is one of the important processes in integrated circuit manufacturing, MEMS processing and other device processing . It is mainly used for the etching of various thin films such as polysilicon, silicon nitride, silicon ...

AI Technical Summary

Problems solved by technology

[0005] Further, in order to form an electrical connection with the MEMS substrate 103 and the base 101, etch the MEMS substrate 103, the dielectric layer to the conductive layer, the etching method is the DRIE method, but due to the vias formed in the DRIE method The hole has a high aspect ratio, generally (aspect ratio) is 10-15:1 or even higher, and the opening size of the through hole is generally less than 5um, filling the trench with a large aspect ratio with metal When it is easy to enclose the air and form holes, the resistance of the through hole will increase, resulting in an increase in the operating voltage of the device above the through hole, resulting in a rise in temperature when working for a long time

[0006] Therefore, in the process of preparing various MEMS devices in the prior art, the through holes formed by the DRIE method have a relatively large aspect ratio, which is easy to form holes when filling metal, resulting in poor filling effect, which makes the performance and good performance of the device The rate is reduced, so it is necessary to improve the existing technology to eliminate the above problems

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