Abstract: A multilayer circuit board provided with multilayer wiring patterns as upper and lower multilayers is provided, in which on a first circuit board 24 with a first wiring pattern 23 formed thereon a copper foil 27 is bonded through an insulating resin layer 25, the patterning is carried out so as to form a second wiring pattern 33, and the upper and lower patterns 23 and 33 are connected to each other by conductive substance 34 filled within an opening portion 32 of the second wiring pattern 33. In accordance with this multilayer circuit board, the quality thereof is improved, the manufacturing thereof is carried out at low cost, and in addition, it becomes possible to form a circuit of high density integration.

Abstract: A novel conductive paste is disclosed which is suitable for use to connect circuit patterns of a printed circuit board.The conductive paste comprises a melt of gallium and a metal element which forms an eutectic mixture with gallium, and metal powder which alloys with gallium uniformly dispersed in the melt. The content of the metal element and the metal powder are selected to control a solid content in the paste at a predetermined working temperature.

Abstract: A novel conductive paste and a method of making the same in which metallic gallium is combined with a metal or alloy which forms a eutectic with gallium in an amount in excess of its limit of solubility in gallium at a specific temperature. This melt is then treated with a metal powder of a second metal or alloy which alloys with gallium to produce a higher melting alloy, the second metal powder being coated on its surface with the eutectic-forming metal.