Circulative reuse treatment method of electric ultrapure water

Abstract

The invention relates to a method for recycling ultra pure water for electronics and belongs to a technique for water treatment. The method comprises the following: a step of removal of suspended impurities with an ultrafiltration system and aerobic degradation with hydrogen peroxide, in which wastewater subjected to ultrafiltration is added with 200 to 500 ppm of hydrogen peroxide; a step of ultraviolet irradiation, in which wastewater added with the hydrogen peroxide are passed through a reactor irradiated by ultraviolet rays with a wave length ranging from 185 to 254nm and a irradiation dose of 50 to 500J / m<2> and kept in a water tank for 20 to 60 minutes; a step of reverse osmosis, in which wastewater subjected to full aerobic degradation treatment is pumped to reverse osmosis membrane block or a nanofiltration device to be filtrated; and a step of mixed bed treatment, in which water subjected to nanofilitration and reverse osmosis treatment is guided to a mixed bed to remove charged ions and other impurities in water. Compared with the prior method for removing TOC through oxidation of ozone, the method is simple and safe in process and makes the treated washing water reused as pure water for high-end electronic products.

Description

Technical field: [0001] The invention relates to a recycling treatment method of the electronic ultrapure water, which belongs to the water treatment technology, in particular to the treatment of cleaning water used in the electronic industry. Background technique: [0002] In many high-tech enterprises that produce electronic products such as microcircuit boards for high-tech products, large-capacity magnetic recording devices, etc., high-purity water is used in large quantities. In nearly every process step in the production of semiconductor electronics, some layer of conductive or insulating material is added to the surface of the silicon wafer. Parts of the surface are etched away with aggressive chemical acids before the next layer is applied. Therefore, in order to ensure thorough rinsing and removal of chemicals on the surface of the silicon wafer, it is necessary to use a hydrophilic polymer cleaning agent for cleaning, and then use a large amount of ultrapure water...

AI Technical Summary

Problems solved by technology

These methods need complex equipment such as an ozone generator and an ozone mixing device to be installed, and have limited effects on the degradation and removal of the polymer cleaning agent in the above-mentioned electronic cleaning water.

After using the above method to treat the cleaning water, most of the organic matter in the cleaning water can be removed, but the residual total organic carbon (TOC) content is above 2000ppb, which cannot be reduced to a lower level, so it cannot be used for cleaning high-end electronic products. The requirement that the total organic carbon (TOC) content in high-purity water is less than 20ppb is only applicable to occasions that require low-end pure water that does not require high total organic carbon (TOC) indicators

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