Electroconductive metal paste

Abstract

This invention provides a low-temperature sintering conductive paste for high density circuit printing which can form a fine circuit having good adhesive force, a smooth surface and low resistance when applied on a substrate and then baked; the conductive paste of the invention uses, as conductive media, in combination with metal fillers having an average particle diameter of 0.5 to 20 mum, ultrafine metal particles having an average particle diameter of not larger than 100 nm, which are set in the state that the surfaces thereof are coated with one compound or more having a group comprising a nitrogen, oxygen, or sulfur atom and capable of coordinate-bonding by a lone pair existing in the atom, as a group capable of coordinate-bonding to a metal element contained in the ultrafine metal particles, and are dispersed uniformly in a resin composition comprising a heat curable resin component, an organic acid anhydride or a derivative thereof or an organic acid, and one or more organic solvent; and thereby it enables low-temperature sintering of the ultrafine metal particles during a heat treatment at a low temperature.

Description

technical field [0001] The present invention relates to a conductive metal paste and a method of making the paste. More specifically, the present invention relates to a conductive metal paste for forming low-impedance fine circuits suitable for high-density digital lines on rigid or flexible printed boards, IC chips, glass boards, ceramic boards, etc., and for use in Methods such as screen printing or disperse printing to form interlayer bonds; also relates to methods of making such conductive metal pastes. technical background [0002] As a method for producing ultrafine metal particles having a very small particle diameter, or at least ultrafine metal particles having an average particle diameter of 100 nm or less, Japanese Patent Application Laid-Open No. 34211 / 1991 discloses ultrafine metal particles having a particle diameter of not more than 10 nm and In its manufacturing method, these particles are prepared by gas evaporation and dispersion in colloidal state. In ad...

AI Technical Summary

Problems solved by technology

However, the current situation is that since the thickness and line width of the formed film are reduced along with the miniaturization of information terminals in recent years, the decrease of line pitch in printed circuits and the increase of circuit fineness in semiconductor devices, the conventional Ointments cannot meet this requirement due to the large diameter of metal powder particles

To illustrate it more concretely, as an example, assume that the thickness of the film is about several micrometers, and there are only two or three metal particles in its thickness direction. There is a relatively large deviation, so the stability of its continuity is not satisfactory

Moreover, since it is composed of a small number of particles, the roughness of the surface is affected by the shape of the metal particles, thereby weakening the smoothness of the surface