Production of high purity Cu microparticles and development of conductive paints using electrostatic colloid solution

Abstract

In recent years, metal microparticles made of Au or Ag have attracted attention as intermetallic bonding materials and low resistance materials of fine interconnects. It is also known that the electron cloud localized on the fine surface of the fine particles has a catalytic effect, and researches on chemical reaction accelerators are being advanced. However, Au and Ag have high material cost, not economical materials. Furthermore, Ag is extremely easily oxidized, and there is a problem in durability of the catalytic effect in the solution. In this research, we considered Cu microparticle formation by Cu three - dimensional tree structure (Cu dendrite). Cu has high electrical conductivity and less oxidizable than Ag. It has an extremely high economic advantage compared with Au. We have succeeded in making high purity Cu dendrites by our previous studies. This Cu dendrite was broken in an aqueous solution using ultrasonic waves. As a result, Cu fine particles having a diameter of about 1 to 10 μm were successfully formed. We also reported that this fine particle was impregnated into a water-soluble paint and succeeded in forming a printer ink with electrical conductivity. Further, by impregnating the methylene blue and Cu dendrite particles are an electrostatic colloidal solution, it was constructed conductive micelles strictures. As a result, we succeeded in strengthening the structure of printed matter using Cu dendrite microparticles.