Production method of electronic-grade sulphuric acid

A sulfuric acid production, electronic-grade technology, applied in chemical instruments and methods, sulfur compounds, inorganic chemistry, etc., can solve problems such as high energy consumption and the difficulty of sulfuric acid reaching electronic-grade standards

Active Publication Date: 2013-11-27
SHANGHAI ZHENGFAN TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the high boiling point of sulfuric acid, the boiling point of 98% sulfuric acid at normal pressure is 338°C, so electric heating wires must be used to heat and distill the sulfuric acid solution in a quartz glass container. Operating at such a high temperature not only consumes high energy, but also It also brings certain safety risks. In addition, due to the strong corrosiveness of concentrated sulfuric acid, the sulfuric acid distilled at high temperature will dissolve some impurities in the glass equipment, making it difficult for the sulfuric acid produced by this method to meet the requirements of integrated circuits. electronic grade standard

Method used

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  • Production method of electronic-grade sulphuric acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] see figure 1 , the implementation steps of embodiment 1 are as follows:

[0039] 1): Provide industrial-grade sulfur trioxide raw materials into the raw material storage tank;

[0040] 2): The above-mentioned sulfur trioxide raw material is transported into the evaporation tank with a centrifugal pump;

[0041] 3): Use hot water to heat the evaporation tank, the heating temperature is controlled at 60°C, and the sulfur trioxide vapor generated by heating enters the absorption tower 2 after passing through the first filter 1;

[0042] 4): In the adsorption tower 2, the sulfur trioxide vapor is absorbed with electronic grade ultrapure water, and the concentration of the absorption solution is adjusted to be 97% ± 0.5% by controlling the flow rate of the sulfur trioxide vapor and the flow rate of the ultrapure water, and the absorption tower The temperature of 2 is controlled at 100°C, and the absorbed solution enters the degassing tower 7 after being cooled by the first...

Embodiment 2

[0048] see figure 1 , the implementation steps of embodiment 2 are as follows:

[0049] 1): Provide industrial-grade sulfur trioxide raw materials into the raw material storage tank;

[0050] 2): press the above-mentioned sulfur trioxide raw material into the evaporation tank with nitrogen;

[0051] 3): Use steam to heat the evaporation tank, the heating temperature is controlled at 70°C, and the sulfur trioxide steam generated by heating enters the absorption tower 2 after passing through the first filter 1;

[0052] 4): In the adsorption tower 2, the sulfur trioxide vapor is absorbed with electronic grade ultrapure water, and the concentration of the absorption solution is adjusted to be 97% ± 0.5% by controlling the flow rate of the sulfur trioxide vapor and the flow rate of the ultrapure water, and the absorption tower The temperature of 2 is controlled at 95°C, and the absorbed solution enters the degassing tower 7 after being cooled by the first cooler 4, and the outle...

Embodiment 3

[0058] see figure 1 , the implementation steps of embodiment 3 are as follows:

[0059] 1): Provide industrial-grade sulfur trioxide raw materials into the raw material storage tank;

[0060] 2): The above-mentioned sulfur trioxide raw material is transported into the evaporation tank with a centrifugal pump;

[0061] 3): Using electric heating wire to heat the evaporation tank, the heating temperature is controlled at 50°C, and the sulfur trioxide vapor generated by heating passes through the first filter 1 and then enters the absorption tower 2;

[0062] 4): In the adsorption tower 2, the sulfur trioxide vapor is absorbed with electronic grade ultrapure water, and the concentration of the absorption solution is adjusted to be 97% ± 0.5% by controlling the flow rate of the sulfur trioxide vapor and the flow rate of the ultrapure water, and the absorption tower The temperature of 2 is controlled at 85°C, and the absorbed solution enters the degassing tower 7 after being cool...

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Abstract

The invention discloses a production method of electronic-grade sulphuric acid. The production method comprises the following steps in sequence: industrial-grade sulfur trioxide raw materials are provided and placed into a raw material storage tank; the sulfur trioxide raw materials are conveyed into an evaporator tank; the evaporator tank is heated; sulfur trioxide steam generated by heating enters into an absorption tower through a filter; the sulfur trioxide steam is absorbed by electronic-grade ultrapure water in the absorption tower, the concentration of absorption liquid is controlled, and the absorbed solution enters into a degassing tower after cooled by a cooler; air stripping is performed on a sulfuric acid solution by the degassing tower through compressed air; the sulfuric acid solution enters into a finished product storage tank after cooled; finally, the final electronic-grade sulphuric acid applied to the integrated circuit industry is obtained after ultrafiltration to remove particles. The operating temperature of the technology, compared with a conventional technology, is lower than 120 DEG C. Therefore, the technology is safer than a high-temperature distillation technology which takes industrial-grade sulfuric acid as raw material, and in addition, compared with adopting equipment made of quartz glass, non-pollution to electronic-grade sulphuric acid products is guaranteed from equipment material.

Description

technical field [0001] The invention relates to a method for producing sulfuric acid, in particular to a method for producing electronic-grade sulfuric acid required for the production of large-scale integrated circuits. Background technique [0002] Sulfuric acid, chemical formula H 2 SO 4 , with a relative molecular mass of 98.08, is a colorless, odorless oily liquid, a strong acid with a high boiling point and low volatility, easily soluble in water, and miscible with water in any ratio. Sulfuric acid is one of the important products in the basic chemical industry. It is not only used as a raw material for many chemical products, but also widely used in other national economic sectors. [0003] Electronic-grade sulfuric acid is currently widely used in integrated circuit manufacturing processes for resist stripping, and the concentration of the most commonly used sulfuric acid is about 96%. Organic pollutants remaining on substrates and related equipment will have adv...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B17/74
Inventor 汤剑波
Owner SHANGHAI ZHENGFAN TECH
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