Double-suspension force-sensitive sensor chip with package stress and temperature drift self-compensation and preparation method

Abstract

The invention provides a double-suspension force-sensitive sensor chip with self-compensation package stress and temperature drift and a preparation method. The chip at least includes: two cantilever beams with the same structure and size formed on one surface of a single crystal silicon substrate, each cantilever beam surface is provided with a reference pressure cavity, and the surface of each reference pressure cavity is covered with a single crystal silicon A pressure-sensitive thin film, and a plurality of resistors are formed on the surface of each single-crystal silicon pressure-sensitive thin film, and each resistor is connected to form a Wheatstone full-bridge detection circuit; in addition, near the connection between each cantilever beam and the single-crystal silicon substrate A stress release groove is formed to release the packaging stress; moreover, one of the two reference pressure chambers communicates with the pressure guide hole through a pressure release channel so that the reference pressure chamber communicates with the outside atmosphere. The sensor of the present invention can realize self-compensation for package stress and zero temperature drift, improve the detection stability of the sensor and the reliability of package environment adaptation; it has the characteristics of small chip size, low cost, suitable for mass production and the like.

Description

technical field [0001] The invention relates to the field of semiconductors, in particular to a dual-suspension force-sensitive sensor chip with package stress and temperature drift self-compensation and a preparation method thereof. Background technique [0002] In recent years, with the rapid development of micro-electromechanical systems (MEMS) technology, silicon-based pressure sensors, as one of the traditional mechanical detection devices of MEMS sensors, have been widely used in aerospace, biochemical medicine, life sciences, automotive electronics and other fields. Especially in recent years, with the first use of MEMS pressure sensors on the Samsung smartphone Galaxy Nexus, more and more smartphone consumer markets will widely use pressure sensors to assist GPS positioning and overcome the lack of GPS positioning under different altitude conditions , making the three-dimensional positioning more accurate. For example: to achieve altitude measurement, GPS-assisted n...

AI Technical Summary

Problems solved by technology

However, this traditional force-sensitive pressure sensor structure still cannot eliminate the influence of the package stress caused by the thermal mismatch of the package material and the residual stress of the sensor itself on the zero temperature drift of the sensor.

Therefore, in order to eliminate the packaging stress caused by thermal mismatch and improve the detection accuracy and stability of the sensor, traditional force-sensitive pressure sensors need to spend a lot of manpower and material resources to study packaging materials and packaging processes, as well as time-consuming sensors. Chip aging process, which greatly increases the manufacturing cost of the force-sensitive pressure sensor and reduces the competitiveness of the market (for details, please refer to the literature: Bowei Li, G Q Zhang, Fengze Hou and Yang Hai. The Effect of Diaphragm on Performance of MEMS Pressure Sensor Packaging. International Conference on Electronic Packaging Technology & High Density Packaging, 2010: 601-606)

In addition, even if the package stress problem caused by thermal mismatch is solved through various efforts, the influence of the residual stress of the sensor itself caused by the insulating passivation layer above the pressure-sensitive film of the force-sensitive pressure sensor on the zero-point temperature drift of the sensor cannot be eliminated.

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