Method and device for preparing carbon dioxide ionized water

Abstract

The invention relates to the field of chip manufacturing and processing, particularly relates to a method for preparing carbon dioxide ionized water for cleaning chips as well as a generating device thereof. The invention aims to provide a method and device for preparing online carbon dioxide ionized water, which have the advantages of simple structure, and capability of increasing the dissolution ratio of carbon dioxide gas in deionized water and effectively improving the stability of ion concentration of the prepared ionized water. The method comprises the following steps: 1) feeding deionized water (DIW) and carbon dioxide (CO2) into a gas-liquid mixing cylinder to carry out complete mixing, wherein the gas-liquid mixing cylinder is provided with a clamping gas film; 2) carrying out ionic conductivity detection on the ionized water discharged from the gas-liquid mixing cylinder, thereby obtaining the conductivity value of the ionized water; 3) comparing the obtained conductivity value of the ionized water with a preset conductivity value, and adjusting a pressure-regulating valve by using a controller so as to control the inlet capacity of the carbon dioxide; and 4) obtaining ionized water with the preset conductivity value.

Description

technical field [0001] The invention relates to the field of chip manufacturing and processing, in particular to a method for preparing carbon dioxide ionized water for chip cleaning and a generating device thereof. Background technique [0002] In chip manufacturing equipment, in order to prevent static electricity from damaging chips being processed, it is necessary to ionize deionized water to eliminate static electricity. At normal temperature, carbon dioxide can be partially dissolved in deionized water to produce hydrogen ions and carbonate ions to form ionized water. After the ionic water is dried, the ions therein become carbon dioxide and volatilize, so no impurities will remain on the processed chip. Therefore, carbon dioxide ionized water is widely used in various process steps of chip manufacturing. Due to the strict requirements on the purity of ionized water in chip manufacturing, mechanical means must not be used to promote the dissolution of carbon dioxide ...

AI Technical Summary

Problems solved by technology

[0003] 1. Carbon dioxide gas cannot be fully dissolved

Carbon dioxide gas and deionized water are mixed in the tee and then mixed through a long mixing pipe. Due to the lack of stirring means, most of the carbon dioxide exists in the form of larger bubbles in the water, and these bubbles reduce the gas-liquid contact area. , making it difficult for carbon dioxide gas to fully dissolve into water

And these bubbles may still exist after the conductivity probe and continue the dissolution process, making the conductivity of the prepared ion water inconsistent with the reading displayed by the controller

In addition, these air bubbles will also stay in the subsequent filter, affecting the flow of the filter

[0004] 2. The ion concentration of the ionized water fluctuates greatly

Due to the long mixing pipeline between the gas-liquid mixing point and the detection point in this preparation method, the detection signal lags, which affects the control ability of the controller and makes the ion concentration of ion water fluctuate greatly.

Furthermore, the preparation method controls the intake of carbon dioxide through the on-off frequency of the solenoid valve, and the intermittent on-off of the solenoid valve makes the flow of carbon dioxide fluctuate greatly, resulting in large fluctuations in the ion concentration of ionized water.

[0005] 3. Large consumption of carbon dioxide

Because part of the carbon dioxide gas is not completely dissolved in the water, but stays in the filter to form bubbles, resulting in waste of carbon dioxide gas

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