Study On A New Al-1%Si Bonding Wire For Encapsulation Of Integrate Circuit

The thesis was related to a Al-l%Si bonding wire for semiconductor element connections used for electrical connection of external leads and the like to electrodes on semiconductor elements. Specifically, the new Al-l%Si bonding wire was capable of greatly reducing the degree of damage of lapse of bonding,and suitable for narrow pitch connections and thin electrode connections.It was able to replace the conventionally used Au wire for Thermosonic welding method.To be obtained,the bonding wire used a material made of the base metal of high-purity aluminum and silicon alloys,and the technology of heated mould continuous casting-drawing was adopted. The transformation of Al-1%Si rod's property in as-casting, as-drawing and as-annealing and the reliability of Al-l%Si ultrafine were researched and evaluated,making use of the measure and test of mechanical and electrical properties and some micro-analysis tools(such as 0M,SEM and XRD).To draw ultrafine wire,it must be to obtain the good quality Al-1%Si rod by the heated mould continuous casting.The specialty rod that possessed smooth surface and column crystal along with the casting direction is propitious to drawing.The key of success for Al-l%Si rod by heated mould continuous casting lied in improving the temperature gradient of liquid-solid zone,as to the position and length of the liquid-solid zone defined.There were changes of some main factor affecting to the solidification zone: mould temperature, casting speed and cooling capability, etc. These factors were conditional and affected each other.In the process of the continuous casting ,all kinds of parameters could be matched and optimized in order to obtain the good quality Al-l%Si rod.Compared with polycrystal ingot ,the properties of mechanics and drawing of the Al-l%Si rod by heated mould continuous casting were excellent .The yield strength of the as-casting sample could reach 64.2 Mpa, enhancing 41.8%, the elongation increased 54.9%. During drawing, the elongation decreased and the strength increased.The changes of the electrical resistance were related to the degree of the transmutation and the process of the heat treatment. The electrical resistance of as-casting Al-l%Si rods was lower,and it could be increased after being drawed and be resumed after being annealed .In this experiment, when the transmutation ration reached 80% and Al-l%Si rods was annealed at 300C for half an hour, the lowest electricalresistance with 0.03042 mm2/m was attained.The Al-l%Si bonding wire produced by the technics of heated mould continuous casting-drawing could satisfy the bonding capability of Thermosonic welding, accroding to GB/T 8646-1998 standard.