在挠性印制板中埋嵌无源和有源元件

文章介绍了在挠性印制板中埋嵌无源和有源元件的方法。通过化学镀Ni(P)电阻可以实现薄膜电阻的埋嵌,并能保证一定的弯折性。通过对芯片进行背面减薄和倒装连接,可以实现有源芯片的埋嵌。随后还对埋嵌元件的可靠性进行了测试。     

双面电镀在先进封装中应用的可行性研究

在晶圆双面及孔的侧壁用一种简单的工序电沉积金属的能力,在先进封装和某些工艺中提供了一些基本的优势。双面电镀样机硬件已经过用配置垂直电镀槽的生产型ECD装置的试验。这种工艺已经成功地在几种不同的金属和多种应用中得以展示。     

Electromigration studies of flip chip Sn95/Sb5 solder bumps on Cr/Cr-Cu/Cu under-bump metallization

The electromigration-induced failure of Sn95/Sb5 flip chip solder bumps was investigated. The failure of the joints was found at the cathode/chip side after current stressing with a density of 1×10⁴ A/cm² at 150°C for 13 sec. The growth of intermetallic compounds (IMCs) was observed at the anode side after current stressing. Voids were found near the current crowding area in the cathode/chip side, and the (Cu,Ni)₆Sn₅ IMC at the cathode/chip end was transformed into the Sn phase. The failure mechanism for Sn95/Sb5 flip chip solder joint is proposed in this paper.     

Effect of silver content on thermal fatigue life of Sn-xAg-0.5Cu flip-chip interconnects

The thermal fatigue properties of Sn-xAg-0.5Cu (x=1, 2, 3, and 4 in mass%) flip-chip interconnects were investigated to study the effect of silver content on thermal fatigue endurance. The solder joints with lower silver context (x=1 and 2) had a greater failure rate compared to those with higher silver content (x=3 and 4) in thermal fatigue testing. Cracks developed in the solders near the solder/chip interface for all joints tested. This crack propagation may be mainly governed by the nature of the solders themselves because the strain-concentrated area was similar for tested alloys independent of the silver content. From the microstructural observation, the fracture was a mixed mode, transgranular and intergranular, independent of the silver content. Higher silver content alloys (x=3 and 4) had finer Sn grains before thermal cycling according to the dispersion of the Ag₃Sn intermetallic compound, and even after the cycling, they suppressed microstructural coarsening, which degrades the fatigue resistance. The fatigue endurance of the solder joints was strongly correlated to the silver content, and solder joints with higher silver content had better fatigue resistance.     

使用超薄型微细布线基板（MLTS）的高密度LSI封装

概述了超高密度薄型基板(MLTS)封装技术的概念、特征和工艺以及应用MLTS封装技术开发的高性能FCBGA和CSP。     

避免发生芯片裂纹的倒装片BGA技术概述

介绍了把断裂力学法应用于倒装片BGA的设计方法。概述了一些关键的材料特性和封装尺寸对倒装片BGA芯片裂纹的影响作用，从而断定基板厚度和芯片厚度是倒装片BGA芯片发生裂纹的两个最重要的因素。     

Complex dynamics of a discrete predator–prey model with the prey subject to the Allee effect

In this paper, complex dynamics of the discrete predator–prey model with the prey subject to the Allee effect are investigated in detail. Firstly, when the prey intrinsic growth rate is not large, the basins of attraction of the equilibrium points of the single population model are given. Secondly, rigorous results on the existence and stability of the equilibrium points of the model are derived, especially, by analyzing the higher order terms, we obtain that the non-hyperbolic extinction equilibrium point is locally asymptotically stable. The existences and bifurcation directions for the flip bifurcation, the Neimark–Sacker bifurcation and codimension-two bifurcations with 1:2 resonance are derived by using the center manifold theorem and the bifurcation theory. We derive that the model only exhibits a supercritical flip bifurcation and it is possible for the model to exhibit a supercritical or subcritical Neimark–Sacker bifurcation at the larger positive equilibrium point. Chaos in the sense of Marotto is proved by analytical methods. Finally, numerical simulations including bifurcation diagrams, phase portraits, sensitivity dependence on the initial values, Lyapunov exponents display new and rich dynamical behaviour. The analytic results and numerical simulations demonstrate that the Allee effect plays a very important role for dynamical behaviour.     

铝/镍/铜UBM厚度对SnAgCu焊点的力学性能及形貌影响

研究了倒装芯片中UBM制备和焊球回流工艺流程。通过改变阻挡层Ni和浸润层Cu的厚度,结合推拉力测试实验,探究了SnAgCu焊点剪切强度的变化规律。研究结果表明,UBM中阻挡层Ni对SnAgCu焊点的力学性能影响最大,而浸润层Cu厚度的增加也能提高SnAgCu焊点的力学性能。进一步对推拉力实验后的焊点形貌进行了SEM观察和EDS分析,得到了焊盘剥离、脆性断裂、焊球剥离、韧性断裂四种不同的焊点失效形式,代表着不同的回流质量,而回流质量主要由UBM的成分和厚度决定。研究结果为倒装焊工艺的优化提供了理论指导。     

红外倒焊机的结构和改进

对准倒焊机是制备混合红外焦平面阵列（ＨＩＲＦＰＡ）所必需的设备。ＨＤＤ－１型红外倒焊机是国内第一台自行研制的光机电仪器。叙述了本仪器的原理、特性和在ＨＩＲＦＰＡ中的应用，讨论了该仪器的对准精度，提出了采用自动校准器改进上、下两个焊接面找平的实施方法。     

氧化层对于倒装焊接质量的影响和分析

利用氧化铟易于溶于酸性溶液的性质,提出了在倒装焊接之前使用酸性溶液对铟柱进行酸洗.在未进行酸洗和进行酸洗的条件下,对比了样品在焊接之后的拉力以及在经过热循环后的盲元率,结果显示酸洗能够降低表面氧化层的影响,有效地改善倒装焊接的质量.