Yasuyuki Hotta

Novel method for simultaneous formation of wires and vias of a printed circuit board using nanoporous body

A new type of a flexible printed circuit board with landless vias is developed using a novel method called interconnection via nanoporous structure (INPS). This method can make wires and vias of the printed circuit board simultaneously by a single photo-exposure process. A new photo-induced selective plating method was used to impregnate a nanoporous substrate with copper, and a new photomask was designed, which constitutes of a completely vacant large hole for via and aggregation patterns of very fine holes for wire. Because of the simple process, the INPS board is characterized by landless vias and very fine circuit. Owing to the structure, it is also characterized by flexibility and detachable wires.

Fabrication of metal core and organic shell nanoparticle packing film for plasmon polariton waveguide

Core-shell Au nanoparticles were synthesized for chemical reaction under mild liquid phase condition. The nanoparticles film was fabricated on a glass substrate for surface plasmon polariton waveguide. The nanoparticle piled up on the substrate made a smooth surface. A waveguide was easily fabricated by the lift-off method and the patterned trench filled method.

A Novel Method for the Fabrication of 3D-wiring within a Nanoporous Membrane for High-density Circuit Substrates

The authors have developed a new wiring method to obtain high-density wiring and fine vias for ultra-thin package substrates. Nanoporous substrates and photoinduced selective plating consisting of photo-exposure and metal plating processes were used. However, when miniaturization of wiring pitch and via diameter advanced, deformation of patterns and irregular deposition of metal between wiring became obvious. In order to solve these problems, alkali resistance of the photosensitizers after photoirradiation was increased by crosslinking the photosensitizer molecules. Consequently, in the case of use of diazido chalcone as a crosslinking agent, the crosslinking reaction advanced effectively without changing a process and it was found to be possible to fabricate wiring or via patterns with the designed width or diameter. So far, we have fabricated penetrated copper via patterns with 30 mum diameters and surface copper wiring patterns with 10 mum widths simultaneously within substrates.

Photocurable Inkjet Ink for Printing on Metallic and Plastic Substrates

A novel vinyl ether monomer was employed to improve curing properties of photocurable inkjet ink. A cationic polymerization system was used and the improved curing properties using a novel hybrid vinyl ether monomer with cyclic ether compounds were demonstrated. The cured UV ink film showed good adhesion on metallic substrates such as stainless steel, copper, aluminum and also plastic substrates. The stability of pigment dispersion in the ink was improved by controlling zeta-potential of the ink. The higher zeta-potential value resulted in stable particle size of the pigment and viscosity of the ink.