Method for packaging pressure sensor with multiple fine leads

Abstract

The invention relates to a method for packaging a pressure sensor with a plurality of fine leads, which comprises the following steps of: providing an enameled wire and a pressure sensor chip, arranging at least one lead in the enameled wire, and arranging a bonding pad on the pressure sensor chip; a cracking structure is formed at one end of the enameled wire; removing the outer skin of the cracked structure to expose the lead terminal; the adjacent lead terminals are separated by metal pieces; welding and fixing the lead terminal on the bonding pad, and forming adjacent but not connected welding spots; forming a low-temperature glass sintering layer to cover the welding spots and fill gaps between the welding spots; forming a silicon nitride packaging structure layer on the surface of the low-temperature glass sintering layer; the thermal expansion coefficient of each layer of material shows good thermal matching performance in a wide temperature range, the material can be used within the range of-70-350 DEG C, packaging is ingenious, silicon nitride and a glass sintering layer are used for packaging, good biocompatibility and use stability are guaranteed, the overall preparation process is simple, and the preparation method is suitable for large-scale production. And an automatic process with relatively high yield and production efficiency can be achieved.

Description

technical field [0001] The invention relates to the technical field of pressure sensors and packaging methods thereof, in particular to a packaging method of pressure sensors with fine multi-lead wires. Background technique [0002] The silicon micro-pressure chip is manufactured using the micro-electro-mechanical system (MEMS) process, which is a multi-disciplinary high-tech field. Its research results have broad application prospects in the national economy. At present, the most developed and widely used MEMS products are silicon micro-pressure sensors, and its product-level applications include intracranial pressure sensors and pressure sensors for aircraft surface skin testing. However, in the prior art, due to the limitations of microsensor structure design and fabrication methods, silicon microsensors can only be used in a specific environment, and in the knowledge of those skilled in the art, a wide range of temperature In the changing environment of the range, the ...

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Problems solved by technology

However, in the prior art, due to the limitations of microsensor structure design and fabrication methods, silicon microsensors can only be used in a specific environment, and in the knowledge of those skilled in the art, a wide range of temperature In the changing environment of the range, the thermal matching problem of the material will change with the change of the temperature, which makes it difficult to design and prepare a miniature pressure sensor that can be applied in the temperature range of -70-350°C; it is also difficult to design and Preparation of miniature pressure sensors with biocompatible features, such as intracranial pressure sensors

[0003] For micro and small sensors, the preparation process is also an important factor in determining whether they can be used in a large threshold environment, and the preparation method itself is also a major difficulty; its main purpose is to connect the sensor chip with one or more leads. The leads are welded together; with the miniaturization of silicon micro-sensors and the continuous improvement of sensor performance and quality requirements, for thin enamelled copper wires with a chip width ≤ 0.5mm, a copper lead diameter ≤ 0.03mm, and adjacent lead wires at a distance of ≤0.02mm miniature pressure sensor, due to the small size of the sensor chip, the micro lead wires are very soft, and the distance between them is small. The lead wires are fine-tuned to achieve separation, and then soldered; however, there are still many problems in this method, for example, for enamelled copper wires adjacent to multiple wires, how to remove the enamelled skin and ensure that the end structure is not worn is a technical difficulty; How to choose the way to hang the solder and ensure that the solder layer is evenly distributed and separated from the parts that do not need to be soldered is also a technical problem, and the selection and packaging of materials ensure good thermal matching performance in a large temperature range, especially for preparations such as cranium. For internal pressure sensors, the biocompatibility of the material also needs to be considered, so its packaging structure needs to be designed more specifically. First, it is necessary to ensure that the solder joints do not stick together during welding. Solder joint stability while preventing ion migration

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