Electrical Conductive Characteristics of Anisotropic Conductive Adhesive Particles
Electrical Conductive Characteristics of Anisotropic Conductive Adhesive Particles
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DOI：
10.1115/1.1604808
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发表时间：
2003-12
影响因子：
1.6
通讯作者：
G. Dou;Y. Chan;Johan Liu
中科院分区：
文献类型：
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作者：
G. Dou;Y. Chan;Johan Liu
在各向异性导电胶粘剂（ACA）互连中，颗粒是电导体，在细间距电子封装中提供电流通路，并通过机械变形界面与芯片凸起和衬底衬垫连接。本基础研究的主要目的是揭示Ni/Au包覆树脂颗粒的导电特性。这种ACA粒子电阻是由两层金属包覆层形成的，这两层金属包覆层是电路中由粒子转变程度决定的两个并联电阻。为了研究颗粒转变程度对颗粒电阻的影响，定义了颗粒转变因子。从ACA粒子的物理模型出发，推导出了ACA粒子的数学电阻函数，即转换因子与粒子几何形状、树脂直径、镍层厚度和金层厚度的积分函数。为了实现该函数的求解，应用了MathCAD软件。由数值解可知，颗粒转变越深，金属包覆层厚度越厚，树脂直径越长，颗粒阻力越小。综上所述，ACA颗粒电阻由颗粒的转变和颗粒的几何形状决定，但转变和镍层厚度比树脂直径和金层厚度更敏感。最后，电阻函数将解释变形后ACA颗粒的导电机理。
In anisotropic conductive adhesive (ACA) interconnections, the particles are electrical conductors providing current paths in the fine pitch electronic packaging as well as physical parts connecting with the chip bumps and the substrate pads through the mechanical deformation interfaces. The primary object of this fundamental research is to reveal the electrical conductive characteristics of Ni/Au coated resin particles. Such an ACA particle resistance is resulted from two metal coated layers, which are two parallel resistors in the circuit determined by the particle transformation degree. In order to investigate the effect of the particle transformation degree upon the particle resistance, the particle transformation factor is defined. The mathematical electrical resistance function of an ACA particle, an integral function of the transformation factor and the particle geometries, resin diameter, nickel layer thickness, and gold layer thickness, is worked out from the physical model of an ACA particle. To carry out the solutions of the function, MathCAD software is applied. According to the numerical solutions, the deeper the particle transformation, the thicker the metal coated layer thicknesses and the longer the resin diameter are, the lower the particle resistance is. In conclusion, it is stated that the ACA particle resistance is determined by the particle transformation and the particle geometries, however, the transformation and the nickel layer thickness are more sensitive than the resin diameter and the gold layer thickness. Finally, the resistance function will explain the conductive mechanism of the deformed ACA particle.