Production process of dielectric isolation type pressure sensor based on flip welding chip

Abstract

The invention discloses a production process of a dielectric isolation type pressure sensor based on a flip welding chip. The pressure sensor comprises a shell and a ceramic substrate arranged on theinner side of the shell. The production process of the dielectric isolation type pressure sensor comprises the following specific steps: printing a thick film circuit on the bottom of the ceramic substrate; brushing glass glaze on the thick film circuit, so that the glass glaze covers the thick film circuit to protect the thick film circuit on the ceramic substrate from being eroded when being applied to various media; flip welding an MEMS pressure sensitive chip on the bottom of the ceramic substrate; and welding a welding point of the thick film circuit on the bottom of the ceramic substratetogether with a flexible circuit board at the top of the ceramic substrate to realize an electrical connection of the MEMS pressure sensitive chip and the flexible circuit board. The purpose of the invention is to provide a pressure sensor with a simple process, to realize the application of the sensor in a harsh environment and a medium, and to realize the stable and reliable work of the MEMS pressure sensor in the harsh environment and the medium with high cost performance.

Description

technical field [0001] The invention belongs to the production field of pressure sensors, and in particular relates to a production process of a medium-isolated pressure sensor based on flip-chip welding. Background technique [0002] A pressure transducer (Pressure Transducer) is a device or device that can sense a pressure signal and convert the pressure signal into an available output electrical signal according to a certain rule. The pressure transducer is usually composed of a pressure sensitive element and a signal processing unit. Compared with traditional mechanical quantity sensors, MEMS pressure sensors based on micro-electromechanical systems can be mass-produced with high precision and low cost with similar integrated circuit technology. [0003] MEMS pressure sensors are thin-film elements that deform when subjected to pressure. This deformation can be measured with strain gauges (piezoresistive type sensing) or by capacitive sensing of the change in distance b...

AI Technical Summary

Problems solved by technology

The common production processes of MEMS pressure sensors include back adhesive chip bonding, eutectic welding and oil filling; the back adhesive chip bonding method is that the pressure sensitive chip is bonded by glue, and then electrically connected by gold wire or aluminum wire. The adhesive is only suitable for clean gas and cannot be used for pressure measurement of other media, and the application range is small; the way of eutectic welding is to seal the pressure chip on the metal shell by eutectic welding, and then pass the gold wire or aluminum wire To achieve electrical connection, the problem of this method is that the cost of the chip is high, there are many laser welding resistance welding processes, the production and packaging process is complicated, and the cost is high; the oil-filled method is to package the pressure sensor chip in a closed structure filled with silicone oil, and the external pressure passes through the silicone oil. From the stainless steel diaphragm to the pressure sensor chip, the problem with this method is that there are many parts, the process is complicated, and the cost of the product is very high

[0004] Therefore, the production and packaging process of the existing MEMS pressure sensor severely limits its application range, and the existing MEMS pressure sensor is not resistant to media, which also limits its application range

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