0-50pa single slice silicon based SOI ultra-low micro pressure sensor and its processing method

Abstract

The invention relates to a single chip silicon substrate SOI sensor with ultra-low micropressure of between 0 and 50 pa. The sensor has high sensitivity and linearity, high temperature resistance and simple process and is suitable for large-scale production. Therefore, the invention also provides a method for processing the sensor. A chip comprises a silicon underlayer (1); insulating layers (2) are covered on two surfaces of the silicon underlayer; a monocrystal silicon film with a thickness of 0.3 micron on the surface of the insulating layer (2) generates a resistor (3); an inner lead wire (4) is connected with the resistor (3); an opening of the back of the chip is provided with an island flap (7) or a flat film no island flap; and a composite elastic film (8) with silicon nitride and silicon dioxide is arranged between the island flap and a frame. Monocrystal silicon is used as the underlayer (1), then an opening (6) is carved on the back of the underlayer; oxygen ions are injected on the front of the silicon chip; the silicon chip is processed by anneal to form a silicon dioxide insulating layer and the monocrystal silicon film; an oxide layer and a P-type conducting layer are thermally grown on the front of the silicon chip, then a resistor area (3) and an inner lead heat pressing pin area (4) are formed on the front of the silicon chip; the monocrystal silicon film on the other areas of the front is eroded to expose the silicon dioxide layer; and the silicon nitride film deposited on the front and the back of the silicon chip and the silicon dioxide on the front are combined into a complementary composite insulating layer.

Description

(1) Technical field [0001] The invention relates to the technical field of force-sensitive sensors, in particular to a 0-50pa monolithic silicon-based SOI ultra-low and micro-pressure sensor. (2) Background technology [0002] At present, domestic ultra-low and micro-pressure sensors are very scarce and expensive, and almost all of them are imported from abroad. In 2000, domestic scholars completed the research project "Silicon Micro Pressure Sensor" of the National Ninth Five-Year Science and Technology Research Project "96-748 Sensor Technology". (Sub-topic 96-748-02-01- / 02) The completed technical indicators are: range 0-300pa, N L <0.5%, accuracy 1.0%, V FS >30mv,V CC 6 volts, overload damage pressure > 140 times. And after the scientific and technological novelty check (December 22, 1999) (management number of the novelty check central station: SJTU99-037), the novelty check result: this achievement reached the leading level of similar international devices...

AI Technical Summary

Problems solved by technology

Now experts in the industry are also producing micro-pressure sensors with a range of 1kpa in small batches in the laboratory, but due to the limitation of equipment conditions, it is impossible to form large-scale production

The 300pa micro-pressure sensor researched and produced in the industry is a diffused silicon pressure sensor produced by bulk micromachining technology. The bridge resistors are isolated by a PN junction, so it is obviously affected by temperature, and its zero-point stability is far less than that of SOI structure.

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