Effect Of Electromigration On The Microstructural Evolution And Orientation Relationship Of Full Intermetallic Compounds Formed On Single Crystal Substrates

Microelectronic packaging technology is the interconnection technology that connects all the units of microelectronic products to achieve the functions of the devices.In the electronics manufacturing industry,different electronic components are associated with PCBs?Printed Circuit Boards?through solder joints.The interconnection metal substrate plays an essential role in electronic Packaging reliability.Ni and Cu both are very common metal substrates.Ni shows a significant amount of solubility in the Cu₆Sn₅.The thermodynamics shows that Ni additive can stabilize the structure of?Cu,Ni?₆Sn₅.Moreover,Cu is being used widely on an industrial level for its better conduction properties than Al and much less susceptibility towards electromigrationThe developing trend towards miniaturization has led to a decrease in the size of solder joints to micro-scale,which caused many severe effects on the interfacial reaction such as solder size,electromigration,thermomigration,crystal orientation,and cross-solder interaction of substrates.Electromigration?EM?has become one of the most alarming critical reliability issues in the flip-chip solder joint.Until now,a lot of electromigration induced different failure modes have been reported in the Sn-based solderjoint.The electromigration induced quick depletion of?IMCs?and under bump metallization?UBM?at the cathode be the mostcommonly occurring failure modes.In this present work,synchrotron radiation real-time imaging technology is used to in situ observe the L-S EM behavior of Cu/Sn/?001?Ni and Cu/Sn/?001?Cu linear interconnects and also examined the growth mechanism with a scanning electron microscope.We also examined the orientation relationships of linear interconnects with Pure Sn as solder and Single Crystal?001?Cu and Ni as substrate).Moreover,the orientation relationship of IMCs with Single crystal?001?Ni and?001?Cu substrate has been studied comprehensively.For the L-S EMbehavior of?001?Cu/Sn/polycrystalline Cu and?001?Ni/Sn/polycrystalline Cu interconnect,the growth mechanism has been observed at different times until it becomes preferred orientation full IMC.The growth rate was 4?m/min under current stressing?001?for Cu/Sn/polycrystalline Cu interconnects and 2.9?m/min for Cu/Sn/?001?Ni.Technically,the current-driven bonding?CDB?micro interconnect method is used.The highly oriented full Cu₆Sn₅ and?Cu,Ni?₆Sn₅ IMC interconnects are firstly fabricated using the CDB method,and no voids at IMC/substrate interfaces have been observed.