Study on improvement of reliability of the super fine pitch microjoint in LSI devuce

在这项研究中，使用各向异性导电粘合剂的大规模集成电路中的倒装芯片微接头的可靠性的改善已被检查。主要从以下三个方面进行了研究：（1）各向异性导电胶倒装芯片倒装互连热应力的理论研究。(2)各向异性导电胶剥离强度的实验研究。(3)利用声学显微镜对树脂材料进行了热应力评价的实验研究，主要结果如下。(1)分析了倒装芯片微焊点的热应力分布，阐明了焊点尺寸、组成LSI的材料的力学和物理性能等因素对热应力的影响。数值计算结果表明，最大压应力产生在外凸点电极处。(2)采用临界能量释放率对各向异性导电胶的剥离强度进行了合理的评价。(3)测试了丙烯酸树脂的声弹性系数。很明显，声弹性系数在拉伸和压缩时是相同的。在此基础上，提出了一种利用声学显微镜对树脂材料进行应力评价的方法。

In this study, the improvement of reliability of the flip-chip microjoints in LSI using an anisotropic conductive adhesive has been examined. The research was conducted from three points of view as follows;(1) Theoretical study for thermal stress in flip-chip face-down interconnection using an anisotropics conductive adhesive.(2) Experimental study for debonding strength of an anisotropic conductive adhesive.(3) Experimental study for thermal stress evaluation of resin material by acoustic microscope.The main results obtained are the following.(1) Thermal stress distribution in flip-chip maicrojoints was analyzed and the effects of some factors (joints size, mechanical and physical properties of materials which composed the LSI) were clarified. The numerical-calculation results showed that the maximum compressive stress generated at the outer bump electrode.(2) The debonding strength of an anisotropic conductive adhesive was rationally evaluated by using the critical energy release rate.(3) The acoustoelasticity coefficient of acryic resin was examined. It became clear that the acoustoelastici coefficient was the same in tension and compression. On the basis of these results, a stress evaluation method of resin material using the acoustic micro scope was proposed.