Patent ID: 6148900
Filing Date: 2000-11-21
Classification: H01R,H05K,Y02P

Abstract:
A method of making a connecting board to be disposed between a base plate having a plurality of surface-bonding pads and a mounting board having a plurality of surface-bonding and mounting pads at corresponding positions to the surface-bonding pads, for connection of the base plate and the mounting board through connection at the surface-bonding pads located on the side of a first surface of the connecting board and at the surface-bonding and mounting pads located on the side of a second surface of the connecting board, the connecting board including a ceramic substrate in the form of a flat plate, having the first surface and the second surface and a plurality of through holes extending between the first and second surfaces, and a plurality of soft metal bodies mounted in the through holes, respectively, each of the soft metal bodies having at least one of a first protruded portion protruding from the first surface so as to have a first protruding height Z1 and a second protruded portion protruding from the second surface so as to have a second protruding height Z2, said first protruding height Z1 and said second protruding height Z2 being different from each other, the method comprising the steps of:metallizing an inner circumferential wall of each of said through holes of said connecting board substrate;preparing a plurality of soft metal balls for forming said respective soft metal bodies, said soft metal balls being larger in diameter than said through holes;mounting said soft metal balls on said connecting board substrate in such a manner that each of said soft metal balls partly gets into each of said through holes and is thereby held in place;heating and melting said soft metal balls and allowing said soft metal balls to be embedded in said through holes and partly protrude downward from said through holes; andcooling and solidifying said soft metal balls.