Method of applying solder.

摘要

A method of precisely depositing accurately defined quantities of solder (21) onto high density circuit patterns (23) on a substrate (25) without use of a solder mask or the like wherein solder paste (21) is originally deposited within a precisely defined transfer member (11) (e.g., graphite block having holes drilled therein), the transfer member (15) then being aligned relative to the respective circuitry such that when both block (11) and substrate (25) are heated, solder flow and deposition will occur without the use of a solder mask or the like. Following deposition, a second circuit member (e.g., flexible circuit) may be electrically coupled to the substrate's conductors (23), the deposited solder providing the coupling medium. Hydrogen gas may be used during the heating of the paste and also during the soldering of the flexible circuit to the substrate. <IMAGE>