Reactive bonding of a flip chip package

摘要

An array of bonding pads including a set of reactive materials is provided on a first substrate. The set of reactive materials is selected to be capable of ignition by magnetic heating induced by time-dependent magnetic field. The magnetic heating can be eddy current heating, hysteresis heating, and/or heating by magnetic relaxation processes. An array of solder balls on a second substrate is brought to contact with the array of bonding pads. A reaction is initiated in the set of magnetic materials by an applied magnetic field. Rapid release of heat during a resulting reaction of the set of reactive materials to form a reacted material melts the solder balls and provides boding between the first substrate and the second substrate. Since the magnetic heating can be localized, the heating and warpage of the substrate can be minimized during the bonding process.

主权项

1. A method of bonding substrates comprising:
providing a first substrate bonded to an array of solder balls; providing a second substrate having an array of bonding pads thereupon, wherein each of said bonding pads comprises at least one unit of a reactive-material-including stack that includes a layer of a first non-magnetic material, a layer of a second non-magnetic material and a magnetic material-including layer comprising a magnetic material and one of said first non-magnetic material and said second non-magnetic material, wherein upon ignition, said first non-magnetic material and said second non-magnetic material react spontaneously to form an alloy or a composite of said first non-magnetic material and said second non-magnetic material; bringing said array of solder balls into contact with said array of bonding pads; and igniting said at least one unit of said reactive-material-including stack by heating said magnetic material through a time-dependent magnetic field, wherein said array of solder balls is bonded to said array of bonding pads through heat generated by a spontaneous reaction of said first non-magnetic material and said second non-magnetic material.