Korean Institute of Surface Engineering

pISSN : 1225-8024 | eISSN : 3399-8403


공학

한국표면공학회지 (55권2호 120-132)

Analysis of cyanide free electroless Au plating solution by capillary elecrophoresis

캐피라리 전기 영동법에 의한 비시안 무전해 Au 도금액의 분석

한재호a,*, 김동현b
Jaeho Hana,*, DongHyun Kimb

a주식회사 이씨텍, b주식회사 엠에스씨
aECTECH Co., Ltd., Incheon, 226165, Republic of Korea bMSC Co., Ltd., Incheon, 21698, Republic of Korea

DOI : 10.5695/JSSE.2022.55.2.120

Abstract

In the non-cyanide-based electroless Au plating solution using thiomalic acid as a complexing agent and aminoethanethiol as a reducing agent, analysis of each component constituting the plating solution is essential for the analysis of the reaction mechanism. And component analysis in the plating solution is important for monitoring component changes in the plating process and optimizing the management method. Capillary Electrophoresis (CE) method is rapid, sensitive and quantitative and could be readily applied to analysis of Aun+ ion, complexing agent and reducing agent in electroless Au plating solution. In this study, the capillary electrophoresis method was used to analyze each component in the electroless Au plating solution in order to elucidate the complex bonding form and the plating mechanism of the non-cyanide-based electroless Au plating bath. The purpose of this study was to establish data for optimizing the monitoring and management method of plating solution components to improve the uniformity of precipitation and stability. As a result, it was confirmed that the analysis of thiomalic acid as a complexing agent and Aun+ ions and the analysis of aminoethanethiol as a reducing agent were possible by capillary electrophoresis. In the newly developed non-cyanide-based electroless Au plating solution, it was confirmed that Aun+ ions exist in the form of Au+ having a charge of +1, and that thiomalic acid and Au+ are combined in a molar ratio of 2 : 1. In addition, it was confirmed that aminoethanethiol can form a complex by combining with Au+ ions depending on conditions as well as acting as a reducing agent.

Keywords

Cyanide free plating; electroless Au plating; Immersion ating; Autocatalytic plating; Capillary Electrophoresis; Complexing agent; Reducing agent.