Formation of precise electrically-conductive pattern using metal colloid I-J ink

A precise electrically conductive pattern was formed by the I-J technique using ink composed of a highly concentrated colloidal dispersion of nano-meter sized silver particles. The silver particles were encapsulated with a block copolymer to forrn protected metal colloid. The I-J Ink was formulated using the metal colloid to form an extremely precise electrically-conductive pattern. The ink exhibited a low viscosity at high colloid concentrations and maintained excellent spontaneous dispersing characteristics that prevented I-J head clogging or "Kogation". A printed line width as small as 20 mum was obtained using a commercial thermal I-J printer. The silver colloid particles were strongly combined with each other to form a dense particle layer on a substrate surface. The electrical resistivity of less than 10(-3) Omega was obtained through baking at a temperature of lower than 300degreesC. The resistivity was reduced to the order of 10(-5) Omega when a metal plating copper layer was formed on the metal colloid layer surface. The practical issues in applying the technique to the preparation of a precise print circuit pattern are discussed.