A process technology that enables eco-friendly silver plating without toxic substances has been developed for the first time in the world, and it is expected to lead innovation in the eco-friendly process and global semiconductor plating technology markets in the future.

The research team of Dr. Lee Ju-yeol and Dr. Kim Se-il of the Energy and Environmental Materials Research Center of the Korea Institute of Materials Science (KIMS, President Choi Cheol-jin) has developed the world's first eco-friendly silver (Ag) plating technology that utilizes phosphorus (P) compounds as a key plating ingredient.

This technology is the result of developing an acid plating solution based on phosphorus compounds that enables silver plating without the use of highly toxic cyanide, thereby forming a uniform and stable silver thin film.

Silver plating is an essential process for improving the transmission performance of electrical signals in semiconductors, electronic components, and circuit boards.

Conventional silver plating technology uses a toxic substance called 'cyanide', which causes environmental and safety problems.

In addition, cyanide plating solution has a major disadvantage in that it cannot be applied to the photolithography process that creates precise patterns for semiconductors.

This is because the alkaline plating solution dissolves the photoresist. Therefore, in order to perform a precise process, it is essential to use an acidic plating solution.

There are also methods of plating without cyanide (non-cyanide silver plating techniques).

The non-cyanide plating technology on the entire surface has the problem that silver ions precipitate under the influence of hydrogen ions in an acidic environment, which makes the plating solution unstable and makes uniform silver plating difficult.

Another disadvantage is that the process is complicated because various additives are added to improve the stability of the plating solution.

Due to these problems, most non-cyanide silver plating technology development has focused on developing neutral or alkaline plating solutions rather than acidic ones.

The result of this research is a technology that stably and uniformly plates silver in an acidic environment without cyanide or additives.

The research team used phosphine ligands to stably maintain silver ions without precipitation and derived the optimal ratio to improve the quality of plating by controlling the concentration of phosphorus-based electrolyte.

Through this, a uniform and high-strength silver plating layer was formed. As a result, the technology implementation that satisfies both environmental friendliness, high-quality silver thin film manufacturing, and process simplification was successfully achieved.

The global industrial plating market is growing rapidly, and the demand for eco-friendly plating technology is increasing, especially as environmental regulations are strengthened. The results of this study can be applied to industries that require high-quality silver plating, such as semiconductor packaging, electronic components, medical devices, optical sensors, and precision components. In addition, it can be said that its industrial value is very large as it can reduce dependence on foreign technology and expand exports with domestic technology.

“This technology not only solves environmental problems that arise during the silver plating process, but also enables high-quality plating required for the manufacturing of semiconductors and electronic components,” said Lee Ju-yeol, a senior researcher at the Materials Research Institute who led the research. “We expect this to be a catalyst for innovation in the industrial field.”

This study was conducted as part of the Korea-Germany international joint technology development project supported by the Ministry of Trade, Industry and Energy and the Korea Institute for Advancement of Technology. The results of the study were published on February 26 in the online edition of Electrochimica Acta (IF:5.5, first author: student researcher Soojin Lee), a world-renowned academic journal in the field of electrochemistry. A domestic patent related to this has also been applied for.