Mitsuru Hasegawa

Effect of inorganic binders on the properties of thick film copper conductor

Adhesion strength and solderability of a copper thick film on alumina substrate were studied. Films were prepared with three kinds of inorganic binders, i.e., glass frits, mixture of glass frits and metal oxides, and metal oxides. The effects of inorganic binders on the adhesion and solderability were examined by analyzing physical and chemical behavior of the inorganic binders in the copper thick film during firing. The films with an addition of glass frit or mixtures of glass frit and metal oxide did not provide good adhesion and solderability simultaneously. However, the copper thick film containing 10 wt.% bismuth oxide had excellent characteristics, i.e. high adhesion strength, good solderability, and low sheet resistivity. >

New thick-film copper paste for ultra-fine-line circuits

Key technologies for processing of a thick-film copper conductor applicable to photolithographic techniques are described. A flexo printer was used to obtain a film of less than 2- mu m thickness on a substrate. Using photolithographic techniques, fine-line circuits with 40- mu m-wide copper conductor lines were realized using copper pastes doped with chalcogens. Dense thin films and good adhesion to the substrate were achieved by doping chalcogens from 0.01 to 0.05 wt.%. Characteristics of these conductor films satisfied the standard requirements for hybrid ICs. >

Fabrication of 200-nm Dot Pattern on 15-m-Long Polymer Sheet Using Sheet Nanoimprint Method

Nanoimprint technology is one of the more promising methods for nano-fabrication. The thermal nanoimprint method can fabricate various kinds of thermoplastic materials and its process consists of heating, pressing, cooling, and separation and a lot of research was reported. We proposed and developed a sheet nanoimprint system that enables for continuous treatment of these four basic steps by introducing a belt-shaped nano-mold. We tried to fabricate dot patterns on polymer films by using a sheet nanoimprint method in this work. A 200 nm in diameter and 240 nm tall dots (aspect ratio 1.4) were formed directly onto a 15-m-long polystyrene film. It is important in the field of industrial applications to fabricate nano-scale patterns over a large area with a high throughput. We demonstrated that the sheet nanoimprint is an attractive method for the direct patterning of nano-scale patterns on thermo-plastic films.