Method for preparing capacitive pressure transducer

Abstract

The invention relates to a method for preparing a capacitive pressure transducer and aims to manufacture a device which has a simple structure and good reliability and repeatability through a relatively simple method. The specific processing method comprises the steps of processing a sensitive diaphragm, processing a capacitive gap, processing an electrode and leading out the electrode, bonding silica glass and so on. The processing of the sensitive diaphragm comprises the steps of etching the capacitive gap by using a tetramethylammonium hydroxide (TMAH) solution, and etching a silica island by using a potassium hydroxide (KOH) solution. The invention is characterized by the etching of the silica island and aims at providing a variable cross-section (octangle) diaphragm. The variable cross-section diaphragm has good linearity and low stress concentration; the capacitive gap has a width of 2-4um, and the etching accuracy of the capacitive gap is easy to control by using the TMAH solution; a Cr / Au electrode is deposited and then is bonded with a glass electrode; after the glass side is protected by glue, photoetching is carried out on the front and the silicon island is etched; and as for bonding, the problems in electrostatic bonding and the water-tightness of the cavity are taken into account, and corresponding designs are made.

Description

technical field [0001] The invention relates to the field of microelectronic machining, in particular to a processing method for a high-precision capacitive pressure sensor based on silicon anisotropic corrosion. Background technique [0002] In industrial production, the measurement of gas and liquid pressure is a very important part. There are many principles and methods of pressure measurement. There are different design methods and considerations for various fields of application or special needs. The current pressure sensor Design methods mainly include: piezoresistive, piezoelectric, capacitive and other types. Capacitive pressure sensors are widely used because of their high sensitivity, low static power consumption, and little influence from temperature. In particular, the development of micro-electro-mechanical systems (MEMS) technology has enabled pressure sensors to be miniaturized, mass-manufactured, and low-cost, and the weak-signal measurement circuit can be f...

AI Technical Summary

Problems solved by technology

But the sensor structure is a square meter structure

In order to improve the linearity of the capacitive pressure sensor, an island membrane structure or a corrugated diaphragm structure is used, but the island diaphragm structure has a large stress concentration, and the corrugated diaphragm structure process is more complicated to realize with large errors, and it is difficult to control the accuracy

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