Double-suspension-type force sensor chip with packaging stress and temperature drift self-compensation function and manufacturing method

Abstract

The invention provides a double-suspension-type force sensor chip with the packaging stress and temperature drift self-compensation function and a manufacturing method. The chip at least comprises two cantilever beams which are formed on one surface of a monocrystal silicon substrate and the same in structure and size, a reference pressure cavity is formed in the surface of each cantilever beam, the surface of each reference pressure cavity is covered with a monocrystal silicon pressure sensitive thin film, and a plurality of resistors are formed on the surface of each monocrystal silicon pressure sensitive thin film and connected to form a Whiston full-bridge detection circuit. In addition, a stress releasing groove is formed in the position, adjacent to the connecting position of each cantilever beam and the monocrystal silicon substrate to release packaging stress. One of the two reference pressure cavities is communicated with a pressure guiding hole through a pressure releasing channel so that the reference pressure cavities can be communicated with the outside atmosphere. According to a force sensor, the packaging stress and zero point temperature drift self-compensation function can be achieved, the detection stability and the packaging environment adaption reliability of the sensor are improved, and the double-suspension-type force sensor chip has the advantages of being small in size, low in cost and suitable for mass production.

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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