Copper Wire Bonding Applied Research In The Print Line Ic Package

Today the semiconductor development stands a very important index of one country' s science and technology level.While two most key factors always guide semiconductor study and industry progress,one is the market request,and another is the cost.The wafer manufacturing cost is continuously being reduced,with the thinner feature size(45nm in production) and bigger wafer size (12inch in production).While not so much trend down in packaging,so the packaging cost is playing a more and more important role than anytime before.Traditional packaging process uses the ultrasonic heat bonding technology and the material is gold wire.However the gold price keeps increase recent years.Per our calculation,if the gold price increases from current 900USD/ounce to 1200USD/ounce,the packaging operation margin will be down to 0.So many kinds of substitute material were studied.Among them, most focused material is copper.Actually copper wire was induced into semiconductor packaging process from 70' s of last century. Copper has better thermal and electrical feature than gold,and a much slower IMC growth than gold.However copper wire also has its notable weak points.The primary two are:Bigger hardness than Gold;Easy to oxidation/corrosion. Bigger hardness sometime will damage the Aluminum pad of silicon bonding pad.Easy to oxidation will reduce the bonding successful rate,especially for high pin count package.So for copper wire bonding,the semiconductor packaging industry must develop relate special equipment,material,process capability to handle,and unfortunately so far the mass production application still focus on low pin count package.This article studies the copper wire bonding application on high pin count package.Chapterl introduces wire bonding process briefly. Chapter2 compares the features of copper and gold.Chapter3 evaluates the copper wire bonding application on high pin count package production.Chapter4 studied the copper wire bonding reliability capability and failure analysis method.Chapter5 forecasts the future development of copper wire bonding.