Abstract
The paper discusses on the bondability and reliability of aluminum (Al) wedge-to-wedge bonding using fine ceramic capillary and ball bonder. Initial trials revealed aluminum build-up and poor capillary life with touch down of 20K or less. Optimizing the process parameters, switching on air-scrub, reducing shape angle to 20° instead of usual 35° and using Al-1wt%Si wire processed with refined grains revealed better capillary life with touch down of 200K without surface burrs. The method is capable of bonding complex looping and sharp acute bends. The data comprising of 1st and 2nd wedge dimensions, wedge pull, wedge shear and fracture mode for 20μm and 50μm Al-1wt%Si wires are presented. High temperature storage of aluminum wedge bonding to different substrate surfaces such as Al-0.5wt%Cu metallization, bare copper and gold plating revealed stable bond. From the wedge pull and tensile data, floor and shelf life of the wire is recommended to be 7days and 6months respectively. Evaluation of gold, copper and silver base bonding wires by this method showed feasible to bond and needs detailed studies to practice. The fusing current of Al-1wt%Si wire for varying diameter from 0.6 to 3mil and wire length from 1 to 20mm are also stated.
