Exposed Die-Top Encapsulation Molding for an Improved High- Performance Flip Chip BGA Package

The recent advancement in high- performance semiconductor packages has been driven by the need for higher pin count and superior heat dissipation. A one-piece cavity lid flip chip ball grid array (BGA) package with high pin count and targeted reliability has emerged as a popular choice. The flip chip technology can accommodate an I/O count of more than five hundreds500, and the die junction temperature can be reduced to a minimum level by a metal heat spreader attachment. None the less, greater expectations on these high-performance packages arose such as better substrate real estate utilization for multiple chips, ease in handling for thinner core substrates, and improved board- level solder joint reliability. A new design of the flip chip BGA package has been looked into for meeting such requirements. By encapsulating the flip chip with molding compound leaving the die top exposed, a planar top surface can be formed. A, and a flat lid can then be mounted on the planar mold/die top surface. In this manner the direct interaction of the metal lid with the substrate can be removed. The new package is thus less rigid under thermal loading and solder joint reliability enhancement is expected. This paper discusses the process development of the new package and its advantages for improved solder joint fatigue life, and being a multichip package and thin core substrate options. Finite-element simulations have been employed for the study of its structural integrity, thermal, and electrical performances. Detailed package and board-level reliability test results will also be reported     

中国石化集团钻井技术现状及展望

随着勘探领域的不断扩大和剩余储量的挖潜，钻井施工存在高陡构造防斜打快、裂缝性地层井漏严重、井壁失稳坍塌、长裸眼小井眼固井、深井小井眼完井、含硫化氢井的井控及防护等难题．中国石化集团通过近几年的技术攻关研究与推广应用，深井超深井钻井、水平井钻井、欠平衡钻井、盐膏层钻井、新型钻井液、保护油气层、固井工艺等技术水平大幅度提高，钻井速度和质量不断提高。介绍了中国石化集团钻井技术的现状，分析了中国石化集团钻井面临的主要技术难点，展望了钻井技术的发展趋势，指出应整合推广应用成熟钻井技术．研究攻克钻井生产中的“瓶颈”技术，进一步开展深井超深井、防斜打快和垂直钻井、超高压喷射、地质导向、分支井复杂井钻井、完井工艺等技术研究，进行连续管钻井、套管钻井、欠平衡钻井完井、智能钻井等前瞻技术研究，以提高中国石化集团的钻井技术水平。     

On the convergence of the inverses of Toeplitz matrices and its applications

Many issues in signal processing involve the inverses of Toeplitz matrices. One widely used technique is to replace Toeplitz matrices with their associated circulant matrices, based on the well-known fact that Toeplitz matrices asymptotically converge to their associated circulant matrices in the weak sense. This often leads to considerable simplification. However, it is well known that such a weak convergence cannot be strengthened into strong convergence. It is this fact that severely limits the usefulness of the close relation between Toeplitz matrices and circulant matrices. Observing that communication receiver design often needs to seek optimality in regard to a data sequence transmitted within finite duration, we define the finite-term strong convergence regarding two families of matrices. We present a condition under which the inverses of a Toeplitz matrix converges in the strong sense to a circulant matrix for finite-term quadratic forms. This builds a critical link in the application of the convergence theorems for the inverses of Toeplitz matrices since the weak convergence generally finds its usefulness in issues associated with minimum mean squared error and the finite-term strong convergence is useful in issues associated with the maximum-likelihood or maximum a posteriori principles.     

低密度强抑制钻井液室内研究

针对普光气田千佛崖组以上陆相地层特点，探索室内低密度低固相条件下影响钻井液流变性能的因素，优选适用于低密度强抑制钻井液的提粘切处理剂、降滤失剂。初步确定室内低密度强抑制钻井液体系配方，同时对钻井液体系进行综合性能评价，结果表明该体系具有良好的抑制防塌及悬浮携砂性。     

脉冲式半导体激光器准直光学系统的设计

根据具体的探测环境和探测精度,通过理论分析,提出了脉冲式半导体激光器准直光束的单透镜设计方法和柱面透镜的设计方法,并且给出了具体的设计参数。可以获得高斯光束的准直发散角为1.48mrad;高斯光束的腰粗为0.325mm。     

依靠科技进步 实现企业腾飞——胜利炼油厂科技兴厂40年巡礼

1966年，在美丽富饶的齐国故都淄水河畔，一个新兴石油加工企业——胜利炼油厂迅速崛起。经过40年成长，已由年加工原油250万吨的联合生产装置，发展成为加工工艺齐全的大型燃料-化工原料型企业，被形象地誉为“齐鲁明珠”。现拥有固定资产72．67亿元，生产及辅助生产装置60余套，年加工原油1000万吨，生产40余种石油化工产品，并为齐鲁乙烯提供优质原料，跻身于我国千万吨炼油厂行列。40年春华秋实，已累计加工原油2．20亿吨，实现工业总产值868亿元，为国民经济的发展和国家的强盛作出了巨大贡献．     

闪光灯泵浦Nd3+:GGG激光特性研究

用闪光灯泵浦掺钕钆镓石榴石(Nd^3 ：GGG)激光晶体，研究了脉冲宽度0．5ms、1ms、1．5ms和2ms的放电泵浦下激光输出，实验获得了1．92J的最大激光能量．     

多孔无机材料的性质及用途

对各种多孔无机材料的制备工艺原理和性质进行了论述，并分析了影响多孔无机材料孔径的因素，介绍了多孔无机材料在国民经济生产中的各种用途，指出了以往研究发展中存在的问题。     

Al、Mo含量对铸造钛合金力学性能的影响

运用正交实验 ,考察了Al、Mo含量对Ti Al Mo 1Zr系铸造钛合金力学性能的影响。试验结果表明 :随Al、Mo含量提高 ,铸造合金的强度增加 ,塑性和冲击韧性降低 ,但Al、Mo的交互作用却使合金塑性提高 ,强度和冲击韧性降低     

高温酸化助排剂HC2-1的研究

为了满足高温油藏和深井酸化作业残酸返排的需要，通过表面活性剂的筛选和复配研究，得到了高温酸化助排剂HC2—1。其性能评价结果表明，HC2—1具有使用浓度低、表面活性高的特点，在20％的HCI溶液中，当其浓度为50mg／L时，表面张力为20．7mN／m；具有良好的耐温性能，在180℃下恒温48h，HC2—1仍保持较高的表面活性；具有良好的耐盐能力，加有HC2—1的20％HCl溶液和CaCO3反应至HCl完全消耗，整个反应过程体系无新相生成且表面张力基本不变；可增大酸液体系的润湿角，进一步降低毛细管阻力，使酸液返排率由46％提高到97％，在促进酸液返排的同时与原油不发生乳化反应。