Method and device for on-line producing carbonic anhydride ion water

Abstract

The invention relates to a method of carbon dioxide ion water online preparation and the device. Carbon dioxide gas passes through a pressure adjusting valve and is subsequently mixed with the deionized water in a tee and enters the mixed tube in the tangential direction. The mixture forms a spire swirl in the mixing chamber of the mixed tube. The bubble in the mixture is broken up under the centrifugal force. The carbon dioxide gas is dissolved into the deionized water to form ion water, which flows out through a discharge pipe. A conductivity probe detects the conductivity in the ion water and inputs the data into the controller and compares with the set conductivity. The controller outputs adjusting signal according to the difference between two conductivities, adjusts the opening of the pressure adjusting valve, regulates the pressure of the carbon dioxide gas and controls the ion concentration of the ion water. The device has a simple structure. Carbon dioxide gas can be sufficiently dissolved under the swirl work in the mixed tube. The controllability of the carbon dioxide concentration can be largely increased.

Description

technical field [0001] The invention relates to a method and a device for preparing carbon dioxide ion water on-line, belonging to the field of semiconductor chip manufacturing. Background technique [0002] In the chip manufacturing process, in order to prevent static electricity from damaging the processed chip, deionized water needs to be ionized to eliminate static electricity. At normal temperature, carbon dioxide gas can be partially dissolved in deionized water to generate hydrogen ions and carbonate ions to form ionized water. Since the ions in the ionized water become carbon dioxide gas and volatilize after drying, no impurities will remain on the processed chip, so 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 stirring must not be used to promote the dissolution of carbon dioxide gas in the water during the preparation of io...

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 three-way pipe and then mixed through a long mixing pipe. Since there is no mechanical stirring, most of the carbon dioxide gas exists in the form of larger bubbles in the ionized water. The contact area of ​​the liquid makes it difficult for carbon dioxide gas to fully dissolve into the ionized water

Furthermore, because these bubbles still exist after the conductivity probe, and there is still a process of continuous dissolution, the conductivity of the prepared ionized water is inconsistent with the reading displayed by the controller.

Moreover, 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, this preparation method controls the intake flow of carbon dioxide gas through the on-off frequency of the electromagnetic valve. Due to the intermittent on-off of the electromagnetic valve, the flow of carbon dioxide gas fluctuates greatly, so the ion concentration of ionized water fluctuates greatly.

[0005] 3. Large consumption of carbon dioxide gas

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

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