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Method for reclaiming au and regenerating etching solution from iodine series etching waste liquid

A technology of etching solution and electrolytic recovery, which is applied in the direction of chemical instruments and methods, instruments, electrolytic components, etc., can solve the problems of difficult regeneration of etching solution, reduction of iodine ion concentration, and reduction of etching ability, so as to inhibit the precipitation of electrolysis and iodine, Stable and efficient regeneration effect

Active Publication Date: 2021-01-12
MATSUDA SANGYO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] However, in the method of Patent Document 1, the following problems arise: the current density fluctuates with the elapse of the processing time, and on the cathode side, due to the electrolysis of water as the current density rises, the pH becomes high and the etching ability decreases. On the other hand, also on the anode side, due to the electrolysis of water as the current density increases, the pH becomes lower and the etching ability becomes excessive.
Moreover, on the anode side, iodine (I 2 ) is precipitated on its electrode, and the iodide ion in the solution (I - ) concentration is reduced, stable and efficient regeneration of etching solution becomes difficult

Method used

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  • Method for reclaiming au and regenerating etching solution from iodine series etching waste liquid
  • Method for reclaiming au and regenerating etching solution from iodine series etching waste liquid
  • Method for reclaiming au and regenerating etching solution from iodine series etching waste liquid

Examples

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Effect test

Embodiment 1

[0031] In the electrolytic cell in which the cathode chamber and the anode chamber were separated by a cation exchange membrane, 500 mL of an etching solution containing Au was supplied to the cathode chamber.

[0032] This Au-containing etching solution was composed of the following components. KI(0.25mol / L)+I 2 (0.14mol / L)+Au(0.03mol / L)

[0033] On the other hand, 500 mL of the solution after recovery of Au (after iodine reduction) was supplied to the anode chamber.

[0034] The solution after recovering Au (after iodine reduction) consisted of the following components.

[0035] KI (0.25mol / L)

[0036] The cathode (counter electrode) uses Ti, and the anode (working electrode) uses IrO coated on Ti 2 material, set the reference electrode as Ag / AgCl. At this time, the impregnation area of ​​the Ti electrode was set to 20 cm 2 , the IrO 2 The impregnation area of ​​the electrode is set to 62cm 2 , and set the current density ratio of the cathode to the anode as 3.1. Th...

Embodiment 2

[0039] Set the impregnation area of ​​the Ti electrode to 2 cm 2 , the IrO 2 The impregnation area of ​​the electrode is set to 100cm 2 , and the current density ratio of the cathode and the anode was set to 50, and the electrolytic treatment was performed under the same conditions as in Example 1.

[0040] Through the above electrolytic treatment, the recovery rate of Au in the cathode chamber was 96.3%. In addition, the change of pH before and after electrolysis was investigated. As a result, in the anode chamber, the pH before electrolysis was 5.01, and it was 4.98 after electrolysis. In the cathode chamber, the pH before electrolysis was 5.11, and it was 5.13 after electrolysis. electrolysis. As a result of investigating the etching performance of the regenerated etching solution, it was confirmed that 12.31 g of Au (Au concentration: 5.73 g / L) was dissolved in the etching solution with a liquid volume of 2.15 L, and that it can be reused as an Au etching solution. use...

Embodiment 3

[0042] The electrolytic treatment was performed under the same conditions as in Example 1 except that the cathode potential was set at -0.95V.

[0043] Through the above electrolytic treatment, the recovery rate of Au in the cathode chamber was 96.1%. In addition, the change of pH before and after electrolysis was investigated. As a result, in the anode chamber, the pH before electrolysis was 4.99, and it was 4.31 after electrolysis. In the cathode chamber, the pH before electrolysis was 4.99, and it was 5.88 after electrolysis. electrolysis. As a result of investigating the etching performance of the regenerated etching solution, it was confirmed that 11.99 g of Au (Au concentration: 5.76 g / L) was dissolved in the etching solution with a liquid volume of 2.08 L, and that it can be reused as an Au etching solution. use.

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Abstract

A method for electrolytically reclaiming Au from a used iodine-based etching solution containing Au and regenerating the etching solution, characterized in that the potential of the cathode is set to -0.75V~-0.95V (reference electrode: Ag / AgCl), and set the current density ratio of the cathode to the anode at 3 to 50 (excluding 3). The object of the present invention is to provide a method of stably and efficiently treating a used iodine-based etching solution (a method of recovering Au and regenerating the iodine-based etching solution) without strict pH control.

Description

technical field [0001] The present invention relates to the treatment of used iodine-based etching solution discharged during microfabrication of Au thin films of various semiconductor components, and to a method capable of stably and efficiently recovering Au from the iodine-based etching waste solution and regenerating the etching solution . Background technique [0002] Highly conductive materials such as Au are used for the wiring of various semiconductor components. Au wiring is formed by microfabrication by wet etching after forming a film using PVD or the like, but at this time the used etchant contains expensive Au. As the etching solution at this time, an iodine-based etching solution is often used, and Au can be recovered from the iodine-based etching solution by the following methods: chemical reduction method using various reducing agents, substitution precipitation method using metal powder, electrolysis Extraction method etc. [0003] On the other hand, in t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25C1/20C23F1/46C25C1/00
CPCC02F1/461C23F1/30C23F1/46C25B1/00C25B15/08C25C1/00C25C1/20
Inventor 佐藤贤吾
Owner MATSUDA SANGYO
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