Ritsumeikan University develop processing technique for fine Cu nanopatterning structure readily formed at high speed

A research group, led by Graduate Student Atsuki Tsuji and Professor Junji Murata from the Graduate School of Science and Engineering at Ritsumeikan University, in collaboration with a group led by Professor Masaru Takizawa from the same department, has announced the development of a processing technique for simple and rapid fine copper (Cu) nanopatterning. A novel processing technique utilizing solid polymer electrolyte membranes (PEM) was developed. By employing a "PEM stamp" featuring a pattern on its surface, patterns with an accuracy of several hundred nanometers can be fabricated in a single process through electrochemical reactions at the contact area with the Cu surface. This advancement is expected to result in a decrease in environmental impact and associated costs. The findings were published in the international academic journal Advanced Materials Interfaces on January 17.

In this study, the research group focused on electrolytic processing, a technique that utilizes the ionization of Cu through electrolysis. Instead of chemicals, they employed a specialized film called PEM.

Through the utilization of this PEM stamp featuring a pattern on its surface, they observed that the process exclusively advances at the point of contact between the Cu and the PEM. This revealed that patterning can be achieved easily and rapidly, akin to stamping on the Cu surface. Additionally, it was observed that Cu ions, ionized through electrolysis, migrate within the PEM and are subsequently redeposited as metal onto the cathode surface.

Various applications of fine Cu nanopatterning are currently underway, including its use in metal wiring for semiconductor devices. Unlike conventional fine nanopatterning methods like lithography, this technique no longer necessitates the use of polymer films (resists) or chemicals to protect unwanted areas, as was previously required. Consequently, it is expected to reduce environmental impact and enhance cost-effectiveness even further.

Murata remarked, "Achieving precise patterning on the Cu surface posed challenges, but through persistent research efforts, in collaboration with students, we succeeded in identifying conditions conducive to processing in the desired shape. This fine Cu nanopatterning technique holds vast potential across various applications, particularly in electronic devices. If challenges such as larger area processing and continuous processing can be overcome, we expect that the developed technique can be practically used as a processing method with low environmental loads and cost."

Journal Information
Publication: Advanced Materials Interfaces
Title: Cu Direct Nanopatterning Using Solid-State Electrochemical Dissolution at the Anode/Polymer Electrolyte Membrane Interface
DOI: 10.1002/admi.202300896