Patent ID: 6409073
Filing Date: 2002-06-25
Classification: G01R,H01L,H05K

Abstract:
A method for transferring a solder to a receiving substrate comprising the steps of:providing a transfer substrate, the transfer substrate having: an insulating layer; a conductive layer formed over the insulating layer, the conductive layer being non-wettable by the solder; a solder receiving stud formed on the conductive layer, the solder receiving stud being formed of a conductive material which is wettable by the solder, the solder receiving stud having a first area; and forming a solder bump on the solder receiving stud, by screen printing the solder onto the solder receiving stud to obtain screen printed solder, and reflowing the screen printed solder; providing the receiving substrate, the receiving substrate having a solder accepting stud formed of a conductive material, the conductive material being wettable by the solder, the solder accepting stud having a second area which is greater than the first area; making physical contact between the solder bump of the transfer substrate and the solder accepting stud of the receiving substrate while the solder bump is in a liquidus state; and subsequently, separating the transfer substrate from the receiving substrate, leaving a majority of the solder bump on the solder accepting stud of the receiving substrate.