Wafer-level vacuum packaging method for MEMS devices

Abstract

The invention provides a wafer-level vacuum encapsulating method for a micro-electromechanical device, which sequentially comprises the following steps of: 1, preparing a capping wafer and a device wafer, wherein the capping wafer is insulated silicon consisting of a front silicon layer, a back silicon layer and a middle silicon dioxide layer; 2, growing sealing rings on the front of the device wafer and the front of the capping wafer; 3, growing solder on the sealing ring on the front of the capping wafer; 4, performing deep silicon etching on the capping wafer by taking the sealing ring as a mask to obtain a groove; 5, growing a getter film on the front of the capping wafer, wherein the pattern of the getter film is obtained by a maskplate during growth; 6, heating to activate the getter film and bonding the capping wafer and the device wafer together by using bonding equipment; 7, growing an antireflection film on the back of the capping wafer, wherein the pattern of the antireflection film is obtained by the maskplate during growth; and 8, cutting the wafers. By adjusting process order, the influence of a next process on a result of a previous process is avoided, and the method is particularly suitable for encapsulating infrared devices.

Description

technical field [0001] The invention relates to a wafer-level vacuum packaging method for a micro-electromechanical device. Background technique [0002] For micro-electromechanical (MEMS) devices, the traditional packaging technology is mainly chip-level packaging. The process flow includes the following steps: firstly prepare the MEMS chip on the silicon wafer; then slice the wafer, release the sacrificial layer, patch, lead wire; finally seal the cap. Among these steps, the steps after releasing the sacrificial layer are all performed on a single chip. Since a wafer can be diced to produce hundreds of chips, the cost of such chip-scale packaging is high. In fact, about 90% of the cost of a finished MEMS device is spent on packaging. Therefore, reducing packaging costs is a major development trend of the MEMS industry. Integrated circuits (ICs) have achieved wafer-level packaging. On the basis of referring to the wafer-level packaging technology of integrated circuits,...

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