Study On Coating Pd Copper Wire In The Semiconductor Packageing Field

Due to the gold price rise quickly, copper bonding wires for LSIinterconnection is attracting more and more attentions for IC packagingdue to its lower cost, better electrical and mechanical properties comparingwith high price gold bonding wires. Since copper wire has it own inherentphysical properties which are different from those of gold wires, it is veryimportant and necessary for packaging industry to compare and evaluatethe bonding performance.In this thesis, the characteristics of gold wire, bare copper wire andcoating Pd copper wire through a series of experiments are studied.(1) Price, thermal conductivity of three kinds of bonding wire (gold,copper, copper coating Pd) are analyzed comparatively. Copper wirecoating Pd has lower price and better heating characteristics.(2)Through storage experiments which expose three kinds bondingwire(gold, copper, copper coating Pd) to the air, judge the different in thestorage time. In this experiment by measure bonding wire pull force andball shear to know oxidation resistance of bonding wire. Gold wire andcopper wire coating pd has good oxidation resistance through storageexperiment.(3)Through the analysis of the bonding machine parameters know thedifference of three kinds of bonding wire(gold, copper, copper coating Pd)in hardness, heat affected zone length and arc. on the comparison ofbonding wire hardness, we use the hardness tester to extrude free air balldirectly. We find that copper wire and Copper wire coating Pd has largerhardness which is favorable to arc but will damage the chip if the bondingmachine parameters larger. Gold wire is soft and bond easily. (4) Through protection gas composition and gas flow rate experimentunderstand the influence of the protection gas and the reasons of thisphenomenon.(5) Through high temperature storage experiments and pressure cookexperiment analysis three bonding wire failure reasons in extremely cruelexperimental conditions. Copper wire coating Pd has better reliability thangold wire and copper wire.Through the above five experiments, coating Pd copper wire in thethree bonding is the most excellent and can be a very good choice tosubstitute gold wire.