Image of copper wiring in aqueous solution
Image of potential near surface
Potential distribution of A-B positions
Citation: K. Hirata and T. Fukuma, et al., Nanoscale, 2018, 10, 14736-14746
Surface analysis technology is essential for clarifying and controlling effects that occur at interfaces between liquids and solids.
Pumps, CMP systems, and plating systems are all composed of solid surface parts that come into contact with fluids, so they require low resistance, low corrosion, and low adhesion.
In particular, changes in local potential at interfaces where liquids and solids are in contact with each other affect precipitation or dissolution of the liquid components, so their proper control is desired.
In CMP systems, copper wiring materials and barrier materials appear at liquid-solid interfaces and are exposed to fluid chemicals in machining or washing processes, which causes localized electrochemical reactions to occur.
Our success in the real-time measurement of local surface potential distribution in liquids at pattern wiring near wafer surfaces has made it possible to predict localized electrochemical reaction phenomena such as precipitation or dissolution.
The open-loop electric potential microscopy (OL-EPM) technology developed by Kanazawa University’s Fukuma Laboratory is capable of performing simultaneous real-time measurements on the surface shape and surface potential distribution of wiring components in fluid whose composition is continually changing. This technology enables to visualize the dissolution behavior occurring at wiring components and barrier layers, as well as the corrosion-inhibiting behavior which results from oxidizing agents and protective film forming agents, facilitating the understanding of such phenomena.
Furthermore, we are currently working to deepen our understanding of CMP and washing phenomena by obtaining 3-dimensional images of potential distribution in fluids near interfaces.