Pressure sensor and manufacturing method thereof

Abstract

The invention provides a pressure sensor and a manufacturing method of the pressure sensor. The manufacturing method of the pressure sensor comprises the steps that a semiconductor substrate is provided, wherein a CMOS circuit, an interconnection circuit and a bottom plate electrode are embedded in the semiconductor substrate, the CMOS circuit, the interconnection circuit and the bottom plate electrode are arranged in a stacked mode, and the interconnection circuit on the periphery of the bottom plate electrode is exposed from the semiconductor substrate; a sacrificial layer is formed on the position, corresponding to the bottom plate electrode, on the semiconductor substrate; a pressure sensing layer is formed on the sacrificial layer and on the semiconductor substrate; the sacrificial layer is removed, and a cavity is defined by the pressure sensing layer and the semiconductor substrate; a pressure conducting layer is formed on the pressure sensing layer and located above the cavity, wherein the pressure sensing layer is formed by forming a silicon germanium-noncrystalline silicon-silicon germanium stacked structure on the sacrificial layer. Compared with the prior art, due to the fact that the composite stacked structure is adopted by the pressure sensing layer, stress in the pressure sensing layer can be reduced; due to the fact that the stacked structure with multiple layers is adopted, the thickness of membranes, made of the same material, of each layer is reduced, stress is greatly reduced, and the performance of devices is improved.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a pressure sensor and a manufacturing method thereof. Background technique [0002] Microelectromechanical systems (MEMS for short) is a multi-disciplinary frontier research field developed on the basis of microelectronics technology. It is a technology that uses semiconductor technology to manufacture microelectromechanical devices. Compared with traditional electromechanical devices, MEMS devices have obvious advantages in high temperature resistance, small size, and low power consumption. After decades of development, it has become one of the world's major scientific and technological fields. It involves electronics, machinery, materials, physics, chemistry, biology, medicine and other disciplines and technologies, and has broad application prospects. [0003] A pressure sensor is a transducer that converts a pressure signal into an electrical signal. According to ...

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Problems solved by technology

[0005] In the prior art, when the pressure sensing layer is formed, the stress is often too large, such as about 200 MPa, so that the formed cavity is deformed, the two plates of the capacitor are not parallel, and even the wafer is deformed and warped, such as Figure 5d shown, thereby seriously affecting the performance and yield of the formed pressure sensor

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