Etching liquid acid concentration measuring device

Abstract

The invention provides an etching liquid acid concentration measuring device. The device comprises a controller, a spectrophotometer, an etching bath, a reference cell, a detector and a solution storage unit, wherein the solution storage unit is communicated with the etching bath through a first pipeline and communicated with the reference cell through a second pipeline, the solution storage unit is used for accommodating etching liquid, the reference cell is used for accommodating reference liquid, and the controller controls the spectrophotometer to illuminate the etching bath and the reference cell at the same time, controls the time, entering the etching bath and the reference cell, of the etching liquid, and also controls the acid concentration of the etching liquid in the etching bath to be different from the acid concentration of the reference liquid in the reference cell; both the etching bath and the reference cell are communicated with the detector, and the detector is used for detecting the wavelengths of light absorbed by the etching liquid in the etching bath and the reference liquid in the reference cell illuminated by the spectrophotometer and converting the wavelength into digital signals for comparison.

Description

technical field [0001] The invention relates to the technical field of display thin film transistor manufacturing, in particular to an etching solution acid concentration measuring device. Background technique [0002] Wet etching is the core process of patterning the metal film layer with an acidic etching solution in the TFT manufacturing process, and then forming the gate (Gate Mol Al), source-drain (Source-Drain Cr) and pixel (ITO) electrodes. Among them, aluminum and molybdenum are often used as conductive materials to form gates and source and drain electrodes. The etching solution can use a variety of different acids, and use a mixture of strong acids (nitric acid, phosphoric acid and glacial acetic acid) to dissolve and redox them. widely used. In the existing etching process, based on the absorptiometry, the light emitted by the light source passes through the measuring cell containing the mixed acid and the reference cell containing pure water, and the light of a ...

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Problems solved by technology

[0003] As the number of etching increases and the life of the chemical solution increases, nitric acid and acetic acid will be continuously consumed, and the concentration of the acid will gradually decrease. The greater the deviation of absorbance, the greater the deviation of the acid concentration will be. The system will mistakenly believe that the acid concentration is up to the standard and reduce the amount of single acid replenishment; and the control of the concentration of the mixed acid of the etching solution is for the source and drain. Too high will cause over-etching, which will cause insufficient driving current and poor display; too low acid concentration will cause insufficient etching, resulting in reduced aperture ratio and reduced brightness and contrast; therefore, it will seriously affect the etching quality

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