Process and design analysis for ultrafine-pitched wiresweep elimination in advanced copper heat spreader BGA package

The semiconductor device trend for increasing functionalities and performances yet with smaller overall feature sizes presents escalating obstacles to the decreasing form factor along with demanding thermal carrying capability required at the package level. To confront this compounding issue, ultrafine-pitch wirebond interconnect coupled with thermally enhanced copper heat spreader attached to the package are introduced. However, the additional copper heat spreader thickness introduced within the package challenges the design of the package's wire, its loop height, and the molding process control to prevent wire sweeping occurrences. This study investigates the impact of different ultrafine pitched wire types, wire loop designs, copper heat spreader structures, and mold material types on eliminating device short from occurring due to the wire sweeping phenomena. A full factorial experiment is performed using an active silicon device packaged in a thermally enhanced ball grid array (BGA) test vehicle. In addition, test characterization is carried out using x-ray and multiinsertions hot/cold continuity tests. Then, a detailed failure analysis is performed by package decapsulation and scanning electron microscopy/energy-dispersive x-ray (SEM/EDX) to confirm the experimental findings. In conclusion, the study finds that for an ultrafine-pitched thermally enhanced BGA package, wire type is insignificant to reduce wire shorting occurrences. However, mold material and copper heat spreader structure using an optimized wire loop design are significant factors in eliminating wiresweep shorting phenomena. This study concludes with a wirebond interconnect and heat slug design recommended along with an improved process parameters and assembly material sets found from the experiment.     

破片式战斗部优化设计技术研究

侧重研究了破片式战斗部装药外形的优化设计技术。提出了装药外形与破片飞散特性（如破片飞散角，分布带宽等）之间的数学描述；建立了圆弧和对数螺线装药外形母线与战斗部其他设计参数间的数学模型。在假定约束条件下，优化设计了破片了聚焦式战斗部的结构参数；静爆试验结果表明，破片分布与理论计算吻合较好。     

MX345芯片及单片机控制

MX345芯片用于产生模拟信令—CTCSS单音.本文在介绍MX345编码/解码器工作原理的基础上,设计出MX345芯片与单片机的接口电路.最后给出控制软件.     

Crystallite growth characteristics in superfine zirconia powders and compacts

Crystallite growth characteristics of coprecipitated superfine zirconia powders have been investigated. It was found that the crystallite growth in powders follows a cubic law at 800 and 1000°C; however, the crystallite size data for compacts of both Y-TZP and YSZ cannot be fitted with a traditional parabolic or cubic law, but with a linear relation between crystallite size and the logarithm of time. In addition, it was also found that the degree of agglomeration of the powders can affect the crystallite growth.     

高度有序多孔氧化铝模板的制备工艺与生长机制的研究

采用二次氧化法制备出高度有序的多孔氧化铝模板，结合扫描电镜和原子力显微镜对其结构、形貌进行观察和表征。研究了铝箔预处理和温度等对多孔氧化铝模板孔洞有序性的影响，讨论了有序孔洞的自组织生长机理。     

-35~#轻柴油的生产

为满足市场发展的需求 ,胜利炼油厂用胜利混合原油为原料 ,根据用户要求成功开发生产了 -3 5 #轻柴油新产品。该产品完全符合国家标准GB2 5 2 -2 0 0 0中 -3 5 #轻柴油的各项质量指标要求 ,为胜利炼油厂赢得市场 ,增加了经济效益     

彩泥玩出夏日魅力

产品特点 主题新潮健康：每套产品都配合儿童的特点以某一主题来设计，如“恐龙世界”通过不同种类和形状的恐龙，启发孩子去探索人类的起源；“快餐中心”让家长与孩子同乐，一齐制作不同的“美食”等等。这使得孩子在玩的过程中增长了见识。[编者按]     

中石油成品油营销之差距与对策

与国外大石油公司相比,当前中石油在成品油终端销售方面还存在一些差距,比如管理较落后,流通费用较高,员工素质偏低,技术手段还不够先进,品牌影响力还不够强等等。要提高中石油在成品油市场上的地位,还需要从企业竞争能力、价值链优化整合、市场定位、营销策略等方面进行不断的探索与努力。     

Geotechnical properties of the soft soil in Guangzhou College City

The paper describes some geotechnical properties of the soft soils in Guangzhou College City, China, which are difficult to both sample and test. Laboratory and in situ tests were carried out to assess the physical and mechanical indices of the soils. The data were statistically analyzed and linear regression undertaken such that equations could be developed by which the geotechnical properties of the soft soils can be predicted. The statistical validity of the degree of correlation confirmed that using these equations, the mechanical indices can be estimated from physical indices determined by routine testing.      

集中供热优化节能自动控制系统的特点

国家十一五规划中明确指出:五年内节能20%。根据供热系统耗能比重和现状,集中供热的节能潜力非常大。安装优化节能集中供热控制系统,并依此提高运行管理水平,可取得事半功倍的节能效果。基于多年持久的调查、研究、试验、产品开发和实际应用,我们体会到:只有从集中供热的特点出发,才能使集中供热控制系统既可靠又简单、价低,达到既确保人体舒适又真正节能的目标。本文将对集中供热优化节能控制系统在热力学模型、计算机控制方案、节能效果、可靠性和软硬件选择原则等方面的特点进行介绍。