초록 ▼

A fluxless method for fusing preformed solder balls to contact pads on a semiconductor package substrate wherein a masking plate having one or more vertical holes corresponding to the contact pads is placed over the package substrate, oxide-free solder balls are placed in the holes, the assembly is

A fluxless method for fusing preformed solder balls to contact pads on a semiconductor package substrate wherein a masking plate having one or more vertical holes corresponding to the contact pads is placed over the package substrate, oxide-free solder balls are placed in the holes, the assembly is preheated to a temperature less than the melting point of the solder, and an energetic beam is directed onto the preformed solder balls to melt them and fuse them to the contact pads.

대표청구항 ▼

[ I claim:] [1.] A method of attaching solder balls to a substrate comprising the steps of:providing a semiconductor package substrate having at least one contact point;providing a movable holding fixture which is operable to transport the package substrate to a plurality of processing locations;pla

[ I claim:] [1.] A method of attaching solder balls to a substrate comprising the steps of:providing a semiconductor package substrate having at least one contact point;providing a movable holding fixture which is operable to transport the package substrate to a plurality of processing locations;placing the package substrate on the holding fixture;moving the holding fixture and substrate package to a first processing location;covering at least a portion of the package substrate with a masking plate, the masking plate including surfaces defining a plurality of holes corresponding to the at least one contact point on the package substrate;moving the holding fixture, substrate package and masking plate to a second processing location;placing solder balls into the plurality of holes in the masking plate, the solder balls having surfaces which are essentially oxide-free;moving the substrate package to a third processing location; preheating the substrate package, masking plate and solder to a temperature not greater than the melting point of the solder balls;moving the substrate package to a fourth processing location; andfusing the solder to said at least one contact point by exposing the solder to an energetic beam comprising a focused, high-energy Xenon light beam.