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Method for refining and purifying etching waste liquid

A technology for refining, purifying and etching waste liquid, which is applied in chemical instruments and methods, ammonium fluoride, ammonium halide and other directions to achieve the effects of high product utilization value, extended application fields and simple process

Active Publication Date: 2021-06-29
盛隆资源再生(无锡)有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] In view of the problems existing in the prior art, the object of the present invention is to provide a method for refining and purifying the etching waste liquid. The method extracts the crude product of ammonium bifluoride by evaporating the etching waste liquid and cooling and crystallizing it, and then undergoes adsorption and nanofiltration The treatment is refined to obtain high-purity ammonium bifluoride, and at the same time, the purification and utilization of evaporated steam are realized, and the comprehensive recycling and utilization of etching waste liquid is realized as a whole. The method is simple in process and low in cost, and can effectively solve the pollution easily caused by waste liquid question

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  • Method for refining and purifying etching waste liquid

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Embodiment 1

[0066] This embodiment provides a method for refining and purifying etching waste liquid, the process flow chart of the method is as follows figure 1 shown, including the following steps:

[0067] (1) Evaporate the waste liquid that semiconductor silicon chip etching process produces, the composition of the etchant that described etching process adopts comprises hydrofluoric acid, ammonium bifluoride and sodium dodecylbenzene sulfonate, and the temperature of described evaporation process is 90°C to obtain steam and evaporated concentrated liquid, the concentration of the evaporated concentrated liquid is 65wt%, and the pH value is 3.5, and the evaporated concentrated liquid is subjected to cooling and crystallization, and the cooling rate of the cooling crystallization is 10°C / h, and the temperature is reduced to At 25°C, the crude product of ammonium bifluoride was obtained with a purity of 97.0wt%;

[0068] (2) The ammonium bifluoride crude product obtained in step (1) is ...

Embodiment 2

[0072] This embodiment provides a method for refining and purifying etching waste liquid, said method comprising the following steps:

[0073] (1) Evaporate the waste liquid produced by the semiconductor silicon chip etching process, the composition of the etchant used in the etching process includes hydrofluoric acid, ammonium fluoride and sodium dodecylbenzenesulfonate, the temperature of the evaporation process at 100°C to obtain steam and evaporated concentrated liquid, the concentration of the evaporated concentrated liquid is 80wt%, and the pH value is 3, and the evaporated concentrated liquid is subjected to cooling crystallization, and the cooling rate of the cooling crystallization is 15°C / h. to 20°C, the crude product of ammonium bifluoride was obtained with a purity of 97.8wt%;

[0074] (2) The ammonium bifluoride crude product obtained in step (1) is redissolved in water, and activated carbon is used for adsorption. The adsorbate is the organic matter added in the ...

Embodiment 3

[0078] This embodiment provides a method for refining and purifying etching waste liquid, said method comprising the following steps:

[0079] (1) Evaporate the waste liquid produced by the semiconductor silicon chip etching process, the composition of the etchant used in the etching process includes ammonium fluoride, ammonium bifluoride and sodium lauryl sulfate, and the temperature of the evaporation treatment is 80 ° C , to obtain steam and evaporated concentrated liquid, the concentration of the evaporated concentrated liquid is 50wt%, and the pH value is 4, and the evaporated concentrated liquid is subjected to cooling and crystallization, and the cooling rate of the cooling crystallization is 5°C / h, and the temperature is lowered to 30°C , to obtain ammonium bifluoride crude product, its purity is 96.2wt%;

[0080] (2) After condensing the steam obtained in step (1) to obtain a condensate, the condensate is a fluorine-containing ammonia solution, and the condensate is a...

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Abstract

The invention provides a method for refining and purifying waste etching liquid. The method comprises the following steps: sequentially evaporating, cooling and crystallizing waste liquid generated by an etching process to obtain a crude ammonium bifluoride product and steam; dissolving the crude ammonium bifluoride product again, then performing adsorption, subjecting the adsorbed solution to nanofiltration, and conducting refining so as to obtain a refined etching solution; and condensing the steam to obtain a condensate, adsorbing the condensate, and performing reverse osmosis to obtain reverse osmosis concentrated water and reverse osmosis fresh water. According to the method, evaporation and cooling crystallization treatment are conducted on the etching waste liquid, preliminary purification is carried out to obtain a crude ammonium bifluoride product, and then the crude ammonium bifluoride product is dissolved and then subjected to adsorption and nanofiltration treatment for refining so as to obtain electronic-grade-purity ammonium bifluoride; steam in the evaporation stage is separated and purified through condensation, adsorption and reverse osmosis treatment, so comprehensive treatment of the etching waste liquid is integrally achieved; and the method is simple in process, low in raw material price and operation cost and wide in application range.

Description

technical field [0001] The invention belongs to the technical field of waste liquid treatment and relates to a method for refining and purifying etching waste liquid. Background technique [0002] With the rapid development of semiconductor and microelectronics technology, the application range of electronic chips is expanding day by day. Based on the needs of chip refinement, the etching of micro-sized patterns is an important factor affecting the performance of chips. Etching technology is an important process for chip production. Wet etching is to use some specific chemical reagents to partially decompose the film to be etched, and convert it into soluble compounds into the water phase to achieve the purpose of etching. According to the choice of chip material, the commonly used etchant mainly includes hydrofluoric acid, which is usually mixed with ammonium fluoride as a buffer to control the etching rate. At the same time, organic additives or Surfactants, based on the ...

Claims

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Application Information

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IPC IPC(8): C02F9/10C01C1/16C09K13/08C02F103/34
CPCC02F9/00C01C1/162C09K13/08C02F1/048C02F2001/007C02F1/441C02F1/283C02F1/28C02F2103/346
Inventor 陈琪郎超
Owner 盛隆资源再生(无锡)有限公司
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