摘要
为了确保表面安装封装体优良的焊点连接,减少LSI封装的翘曲是一关键性的问题。把有限元和各种计算方法进行不同地结合,是研究预测薄型小外形封装(TSOP)翘曲问题的最佳方法。研究结果表明预测翘曲问题最合适的方法是使用多层壳体元缩减切变模量和体积模量,计算出粘弹性GK。所有的计算结果证明化合物厚度比为1.2,会使大芯片TSOP的翘曲问题最小化。对小芯片TSOP而言,化合物厚度比为2.0～2.9,减轻了封装翘曲问题。小芯片TSOP的翘曲显示出严重的鞍形状况。封装的翘曲率及翘曲幅度依赖于模塑料的特性。
The reduction of the warpage of LSI package is a critical issue to ensure good solder joint connection in surface mount. In this article, different combinations of finite element and calculating methods were used to investigate the best method for predicting the thin small outline packages (TSOP) warpage. The results indicate that viscoelastic-GK calculation with relaxation of shear modulus and of bulk modulus using the multilayer shell element is the most appropriate method for predicting the warpage. All calculations confirm that a compound thickness ratio of 1.2 results in minimal warpage for a large chip TSOP. However, for a small chip TSOP, a compound thickness ratio of 2.0 ~ 2.9 reduces the warpage. The warpage of small chip TSOP shows a severe saddle shape. The ratio and the magnitude of warpage depend on the compound properties.
出处
《电子与封装》
2003年第3期16-22,共7页
Electronics & Packaging
关键词
薄型小外形封装
粘弹性翘曲
化合物厚度比匕
多层壳体元
Thin small outline packages (TSOP), Viscoelastic warpage, Compound thickness ratio, Multilayer shell element
