Method for testing content of aluminum ions in aluminum etching liquid

Abstract

The invention provides a method for testing the content of aluminum ions in aluminum etching liquid. Automatic titration is carried out by automatic potentiometric titration apparatuses. The method includes carrying out thorough complexation on the aluminum ions in aluminum etching liquid samples by excessive EDTA-Na2 (ethylene diamine tetraacetic acid-Na2) solution by the aid of complexation reaction on EDTA-Na2 and the aluminum ions; carrying out back titration on excessive EDTA-Na2 by the aid of copper sulfate standard liquid; judging titration endpoints by the aid of sudden change of solution conductivity at the titration endpoints. The method has the advantages that test instruments are inexpensive as compared with flame atomic absorption spectrophometry and plasma emission spectrometry for testing the content of aluminum ions mainly by the aid of instruments, and the method is low in test cost; accurate and quick test results can be obtained by the method as compared with indicator color development back titration methods mainly by the aid of manual titration, and accordingly the method is a perfect scheme for monitoring the content of aluminum ions in aluminic acid in current laboratories and in an online manner.

Description

technical field [0001] The invention relates to the production field of display panels, in particular to a method for testing aluminum ion content in an aluminum etching solution. Background technique [0002] Thin Film Transistor (TFT) technology is a large-scale semiconductor integrated circuit technology using new materials and new processes. Fine various films, and process the films by etching, peeling, etc. to manufacture integrated circuits. [0003] 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), source-drain (Source-Drain) and pixel 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. It has bee...

AI Technical Summary

Problems solved by technology

[0010] At present, the methods for detecting the concentration of aluminum ions in aqueous solution include flame atomic absorption spectrophotometry, plasma emission spectrometry, and indicator color back titration, but the first two methods: the matrix interference is more complicated, and the detection speed is also slow; the instrument is expensive, The required test conditions (dust-free) are relatively harsh

Moreover, the concentration of aluminum ions in alumina acid is relatively high (6000-10000ppm), and the acidity of the solution is high. Using these two methods will cause irreversible damage to the instrument, and if a large amount of dilution is performed, the result will be inaccurate.

Secondly, both of these methods need to use expensive standard solutions to prepare standard curves, which greatly increases the cost of testing

However, when the indicator color back titration method is used, the subjective judgment has a great influence, resulting in a large error in the result.

In short, the existing aluminum ion concentration detection methods are not able to quickly and directly detect the aluminum ion concentration in the alumina acid etching solution

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