Research On Preparation Technology Of BGA Solder Ball Used For High Density Packing

With the rapid development of electronic products,electronic packaging has a development trend of high density,intelligent.The birth of ball grid array packaging technology have made electronic products have higher packaging reliability,better heat dispersion and electronic properties,it is a high density packaging technology that most widely used.Solder ball is the core material of ball grid array packaging,the quality of solder ball determines the quality of packaging,so it is important to study the production process of solder ball.This article takes cutting-remelting technology to prepare BGA solder balls under different process parameters,experiments were conducted to study the effect of different spheroidizing temperature,nodularizer,spheroidizing interval on real sphericity,surface quality,oxygen content of BGA solder balls,and the quality of different ingredient BGA solder balls prepared under the same process parameter.The results show that with the increase of spheroidizing temperature,the real sphericity of BGA solder balls increases first and then decreases,the surface quality gets better before it goes bad,the oxygen content raises gradually,they have the highest real sphericity of 97.73% when the spheroidizing temperature is 300℃,the oxygen content of solder balls is 0.009wt%,and they have an excellent surface flatness and smoothness,there are no obvious defects on surface,surface quality of solder balls is the best,so the best spheroidizing temperature is 300℃.The BGA solder balls have the highest real sphericity,the lowest degree of oxidation and the best surface quality when the nodularizer is peanut oil,it means that peanut oil has the best result of spheroidization;castor oil takes second place,the real sphericity of solder balls is97.28%,the surface of solder balls is slightly rough,the oxygen content of solder balls is 0.028wt%;engine oil has a worse result of spheroidization,the solder balls have a real sphericity of 96.85%,poor surface quality and high degree of oxidation;silicone oil has the worst result of spheroidization,the real sphericity of solder balls is only88.67%,and solder balls have poor surface quality and high oxygen content.With the increase of spheroidizing interval,the real sphericity of BGA solder balls shows an increasing tendency,the surface quality gets better before it goes bad,the oxygen content raises gradually,when the spheroidizing interval are 600 mm and 700 mm,the real sphericity of BGA solder balls are 97.73% and 97.85% respectively,the oxygencontent are 0.009wt% and 0.0093wt%,and the surface quality of them are both good,when the spheroidizing interval is 800 mm,the true sphericity of solder balls is 97.87%,but the surface quality is slightly worse and the oxygen content is higher,overall,when the spheroidizing interval is 600-700 mm,the result of spheroidization is the best.At the same process conditions,the true sphericity of Sn3Ag0.5Cu solder balls is98.2%,the oxygen content is 0.015wt%,the solder balls have a slightly rough surface;the true sphericity of Sn0.7Cu solder balls is 97.86%,the oxygen content is 0.026wt%,there are a small amount of bumps on the surface of solder balls,the solder balls have a rough surface,and local area has different degree of oxidation,the surface quality is poor;the true sphericity of 63Sn37 Pb solder balls is 97.73%,the oxygen content is0.009wt%,the surface of solder balls is smooth and no defects,surface quality is better.