Wafer level vacuum packaging MEMS crystal oscillator and preparation method thereof

Abstract

The invention provides a wafer level vacuum packaging MEMS crystal oscillator and a preparation method thereof. The crystal oscillator includes a substrate, a substrate supporting layer, a crystal oscillator main body structure composed of a fixed structure, a movable structure and metal interconnection, and a cap material. The fixed structure is located above the substrate supporting layer; the movable structure is connected to anchor points on the substrate supporting layer through a bridge arm, and can perform relative motion with the fixed structure; the metal interconnection is composed of metal lines and bonding points, wherein the metal lines respectively connect the anchor points and the fixed structure to corresponding bonding points; crystal oscillator fixed and movable structure domains are enclosed by columns; with the columns as linking points, the cap material realizes integral vacuum packaging with the substrate; MEMS crystal oscillator fixed and movable structures are defined on the substrate to form the columns; the movable structure is released, and finally the cap material and the columns perform vacuum bonding to realize MEMS crystal oscillator wafer level vacuum packaging. The structure and method of the invention are completely compatible with the CMOS process, fully take the advantage of full automation, have simple processes of vacuum packaging, and are in favor of popularization and application.

Description

technical field [0001] The invention relates to the technical field of semiconductor integrated circuits, and in particular to a wafer-level vacuum packaged MEMS crystal oscillator and a preparation method thereof. Background technique [0002] The frequency signal is as important to all electronic products as the heartbeat is to the life of all animals. The actions of all electronic circuits use this high-repeatability and high-stability frequency signal as a reference signal source. A well-designed frequency signal is an important basis for the system to achieve high-efficiency, continuous and stable work. [0003] Components that generate signal frequencies can be divided into three categories: passive crystal oscillators, active crystal oscillators, and multi-output clock generators, which are widely used in modern electronic products. The current mainstream crystal oscillator technology can be divided into traditional quartz crystal oscillator and MEMS crystal oscillat...

AI Technical Summary

Problems solved by technology

[0009] The present invention solves the technical problem that the wafer-level vacuum packaging of MEMS crystal oscillators is limited due to high-temperature polysilicon epitaxy technology, resulting in a large limitation of the wafer-level vacuum packaging process of MEMS crystal oscillators, and the technical problem that it cannot be compatible with the CMOS process.

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