Feasibility of Lead-Free Solder Bumps on Ultrasonic Flip Chip Bonding
|School||Harbin Institute of Technology|
|Course||Materials Processing Engineering|
|Keywords||Lead - free solder bumps Ultrasonic flip chip bonding Feasibility|
One of the key technologies of the area array package is a production of the the interconnect solder joints (solder interconnect joint) . Currently , the production of the interconnect solder joints of remelting method including the overall heating of the hot air , infrared and hot plate remelting . In recent years , the higher melting point of lead-free solder alloy has begun to be widely used in microelectronic interconnect manufacturing , traditional overall heating methods such as infrared or hot air caused by chips and printed circuit heat affected more prominent . Sn3.5Ag lead - free solder bumps for the object to study the feasibility of the heating source to unleaded solder bump flip chip soldering . Without heating source an ultrasonic flip chip bonding method , the welding temperature is low , is a locally concentrated heating , help to resolve the problem of the heat affected , compared with conventional remelting method , the flip chip interconnection morphology and microstructure of the solder has a significant organizational characteristics . The main subject of study the feasibility of the lead-free solder bumps in Sn3.5Ag ultrasonic flip chip bonding , ultrasonic flip chip bonding interconnection solder joint macro - morphological and microstructural features . This study mainly includes the following aspects : ( 1 ) study the feasibility of Sn3.5Ag lead-free solder bump flip-chip soldering . Experimental verification Sn3.5Ag lead-free solder bump flip-chip the welding feasibility and operability . (2) a variety of ultrasonic flip chip bonding experiment: plus brazing agent lead - free solder bumps ultrasonic flip chip bonding, the ultrasonic flip-chip bonding to change the material system , and the lead - free solder bump and an intermetallic compound of ultrasound down mounted welding , experimental basis for further study ultrasonic flip chip bonding mechanism . ( 3 ) analysis of the characteristics of the interconnect macro- morphology and microstructure of the solder joints ; summarizes the different process conditions , the interconnect solder joint height , the center radial diameter shape changes ; observation and analysis of IMC and solder organization Ag3Sn and changes in grain shape .