Rapid responding miniature capacitance type humidity-sensitive element with porous upper electrode and parallel board electrode

Abstract

The invention discloses a rapid responding miniature capacitance type humidity-sensitive element with a porous upper electrode and a parallel board electrode. The porous upper electrode, a PI humidity sensing film, the board lower electrode, an SiO2 insulation layer and an Si substrate are arranged from top to bottom, wherein the upper electrode is provided with a plurality of upper electrode pores formed neatly, and a lower electrode lead hole is formed in the PI humidity sensing film. During manufacturing, a wafer is cleaned first, the wafer is oxidized to form the insulation layer, vapor deposition is carried out on the lower electrode, the lower electrode is coated with polyimide acid and subjected to imidization, vapor deposition is carried out on the upper electrode, porous patterns of the upper electrode are etched through phosphoric acid, the phosphoric acid is used to etch the electrode, plasma is used to etch the humidity sensing film to form wafer sliding channels, the plasma is used to etch the humidity sensing film to form the lower electrode lead hole, and slicing, argon welding and packaging are carried out finally. The rapid responding miniature capacitance type humidity-sensitive element with the porous upper electrode and the parallel board electrode has the advantages that the responding time of the humidity-sensitive element with the porous upper electrode can be improved to the largest extent compared with a grid-shaped upper electrode under the same condition.

Description

technical field [0001] The invention belongs to the technical field of humidity measurement and control, and relates to a miniature fast-response hole-shaped upper electrode parallel plate capacitive humidity sensor. Background technique [0002] Humidity measurement and control are closely related to social life, industrial and agricultural production, etc. Some fields, such as the diagnosis and treatment of respiratory diseases, fuel cell vehicles, etc., not only require the humidity sensor to have static characteristics such as accuracy and reliability, but also require the humidity sensor to quickly respond to the transient changes in the measured ambient humidity. The static characteristics of the existing humidity sensitive components are relatively good, but the dynamic characteristics of their marketed products are not satisfactory (usually tens of seconds). [0003] Currently widely used grid-shaped upper electrode parallel plate capacitive humidity sensors are mos...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a miniature fast-response hole-shaped upper electrode parallel-plate capacitive humidity sensor, which does not need a current equalizer, and solves the problem that the existing grid-shaped upper electrode parallel-plate capacitive humidity sensor must be set to occupy a considerable area of ​​the upper electrode. Proportional and wide upper electrode current equalization strips lead to too long diffusion path of water vapor molecules, so that the effect of improving the response time of the humidity sensor by reducing the width of the grid-shaped upper electrode grid teeth cannot be obvious

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