Patent ID: 6119927
Filing Date: 2000-09-19
Classification: B23K,H05K

Abstract:
A method for attaching solder balls to a substrate in a predetermined pattern defined on the substrate comprising the steps of:providing an alignment plate comprising a plurality of through-holes in a pattern which corresponds to the predetermined pattern, said through-holes having a diameter slightly larger than the diameter of the solder balls;placing the alignment plate over the substrate so that the through-holes of the alignment plate are aligned with the predetermined pattern on the substrate;loading a solder ball into each hole of the alignment plate whereby each solder ball falls into contact at a location defining the predetermined pattern on the substrate;heating the solder balls in a vacuum to a temperature sufficient to reduce oxides;heating the solder balls in an inert atmosphere to a temperature sufficient to melt the solder balls; andcooling the melted solder balls sufficiently to resolidify the solder balls which bond to the substrate.