A wafer-level pulling method includes securing a top holder to a plurality of chips; and securing a bottom holder to a wafer, wherein the plurality of chips are bonded to the wafer by a plurality of solder bumps. The wafer-level pulling method further includes softening the plurality of solder bumps; and stretching the plurality of softened solder bumps.

A wafer-level pulling method includes securing a top holder to a plurality of chips. The method further includes securing a bottom holder to a wafer, wherein the plurality of chips are bonded to the wafer by a plurality of solder bumps. The method further includes softening the plurality of solder bumps. The method further includes stretching the plurality of softened solder bumps, wherein stretching the plurality of softened solder bumps comprises leveling the plurality of chips using a plurality of levelling devices separated from the plurality of chips, and a first levelling device of the plurality of levelling devices has a different structure from a second levelling device of the plurality of levelling devices.

A method of producing a solder bump joint includes heating a solder bump comprising tin above a melting temperature of the solder bump, wherein the solder bumps comprises eutectic SnBi compound, and the eutectic SnBi compound is free of Ag. The method further includes stretching the solder bump to increase a height of the solder bump, wherein stretching the solder bump forms lamellar structures having a contact angle of less than 90. The method further includes cooling down the solder bump.

A wafer-level pulling method includes securing a top holder to a plurality of chips. The method further includes securing a bottom holder to a wafer, wherein the plurality of chips are bonded to the wafer by a plurality of solder bumps. The method further includes softening the plurality of solder bumps. The method further includes stretching the plurality of softened solder bumps, wherein stretching the plurality of softened solder bumps comprises leveling the plurality of chips using a plurality of levelling devices separated from the plurality of chips, and a first levelling device of the plurality of levelling devices has a different structure from a second levelling device of the plurality of levelling devices.

A method of producing a solder bump joint includes heating a solder bump comprising tin above a melting temperature of the solder bump, wherein the solder bumps comprises eutectic SnBi compound, and the eutectic Sn-Bi compound is free of Ag. The method further includes stretching the solder bump to increase a height of the solder bump, wherein stretching the solder bump forms lamellar structures having a contact angle of less than 90. The method further includes cooling down the solder bump.