MEMS fiber pressure sensor and manufacturing method thereof

Abstract

The present invention discloses an MEMS fiber pressure sensor and a manufacturing method thereof. The sensor comprises fibers, a pressure sensing element and a pedestal. A fiber groove is arranged on the upper surface of the substrate, and the fiber is installed in the fiber groove; the pressure sensing element has the same size as the pedestal, and the lower surface of the pressure sensing element is connected with the upper surface of the pedestal through anodic bonding; and there is a certain distance between one end of the fiber and the pressure sensing element to form a Fabry-Perot cavity. The MEMS fiber pressure sensor is small in size and can be produced in batch, the manufacturing method is simple, the mechanical property is high, the temperature coefficient is low and the sensitivity is high, etc.

Description

technical field [0001] The invention relates to the field of optical fiber MEMS sensing, in particular to a MEMS optical fiber pressure sensor and a manufacturing method. Background technique [0002] Optical fiber MEMS sensors are very practical in many application fields because of their miniaturization, wide response frequency range, high sensitivity, and low cost. Compared with other traditional sensors, the optical fiber MEMS sensor has stronger adaptability in harsh environments such as strong electromagnetic interference and high temperature; The distribution of physical quantities such as pressure and temperature in the sensor; MEMS devices are suitable for large-scale integrated production, which greatly reduces the production cost of sensors. [0003] The existing optical fiber sensor based on Fabry-Perot cavity mainly consists of a silicon wafer, a cut fiber end face and an air cavity in the middle to form an optical resonant cavity, or two cut fiber end faces ar...

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Problems solved by technology

However, for this type of sensor, the external pressure, the cavity length change, and the directions of the incident and reflected light are all in the same horizontal system. Once the pressure is too high, there will be a problem that the two reflective end surfaces will contact each other, and it will cause irreparable damage to the diaphragm. damage and fiber fixation issues

In addition, there is another type of miniature pressure sensor formed by using SU-8 glue, such as the Chinese patent "Miniature SU-8 Optical Fiber Fabry-Perot Pressure Sensor and Its Preparation Method" with the authorized patent number 201310012946.5, which discloses a method using The near-ultraviolet lithography SU-8 photoresist layer forms the displacement column and the positioning groove of the optical fiber. The required silicon film thickness is formed through a wet etching process, and epoxy resin is used for bonding and packaging. However, when the temperature is too high, the epoxy The bonding effect of the resin glue is reduced, the temperature performance of the sensor is not good, and two alignment photolithography is used on the same surface of the silicon wafer, the requirements for the alignment accuracy of the photolithography are relatively high, and the processing and manufacturing process is relatively complicated

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