Wafer-level packaging structure and packaging method of sensor of integrated MEMS (micro-electromechanical system) device

Abstract

The invention discloses a packaging method for a pressure sensor chip and a pressure sensor. The method comprises the following steps of providing a pressure sensor chip, and forming a protective layer on an MEMS (micro-electromechanical system) device layer, wherein a welding pad is exposed to the protective layer; forming a sacrifice layer above the protective layer, wherein the position of the welding pad is exposed to the sacrifice layer; forming a first metal layer above the welding pad; forming a second metal layer above the first metal layer and the sacrifice layer; and etching the second metal layer, and forming a welding ball on the first metal layer. According to the invention, in the steps of etching the sacrifice layer and a metal interconnection layer, because corresponding thin parts of a groove of a sensing component are protected by the protective layer, the sensing component is not damaged, and the reliability of the component is greatly improved, so that the pressure sensor chip can be packaged by using BGA (ball grid array), therefore, the packaging size is reduced, the volume of the component is reduced, the cost is relatively low, and products are optimized.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a wafer-level packaging structure and packaging method of a pressure sensor. Background technique [0002] MEMS sensors have been used in various fields. Due to the needs of the working environment, MEMS sensors must adopt an effective packaging structure and packaging method. The traditional packaging type is mainly chip-level packaging. Usually, a bare chip is placed in a ceramic tube. The shell is connected to the pins through gold wire solder balls, and the cover plate on it is connected to the shell by solder or ceramic sealing to complete the packaging process of the bare chip. Since many chips can be cut out on one wafer, this In the packaging method, each chip needs to be tested and packaged, resulting in an increase in cost. [0003] In response to the above problems, people have developed other packaging methods, which manufacture the ASIC chip and the MEMS c...

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Problems solved by technology

[0002] MEMS sensors have been used in various fields. Due to the needs of the working environment, MEMS sensors must adopt an effective packaging structure and packaging method. The traditional packaging type is mainly chip-level packaging. Usually, a bare chip is placed in a ceramic tube. The shell is connected to the pins through gold wire solder balls, and the cover plate on it is connected to the shell by solder or ceramic sealing to complete the packaging process of the bare chip. Since many chips can be cut out on one wafer, this The packaging method requires testing and packaging for each chip, resulting in an increase in cost

[0003] In response to the above problems, people have developed other packaging methods, which manufacture the ASIC chip and the MEMS chip on two independent substrates, and then package the two chips together through a bonding process to form a MEMS device. Wafer-level packaging, but the packaging method using two substrates greatly reduces the degree of integration, reduces the utilization rate of the substrate, increases the additional packaging area, and increases the package size, which is not conducive to adapting to the small size of the MEMS device package. development trend

At the same time, the solder used in the packaging process is gold-tin alloy, lead-tin alloy, etc. These materials are not fully compatible with the standard CMOS process

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