功率裸芯片的质量与可靠性保证方法

论述了常规裸芯片质量与可靠性保证的标准和技术,针对功率器件裸芯片,提出了高性能和高可靠性设计、制造工艺保障、验证筛选等质量与可靠性保证方法和技术途径;讨论了采用临时封装夹具技术,对功率裸芯片进行热敏参数筛选、结温控制老化筛选、高温高压反偏筛选等,最终实现对功率裸芯片100%的筛选,满足MCM和HIC对功率裸芯片的质量与可靠性要求。     

应用于并行直流转换电源的均流控制芯片设计

为实现并行直流转换电源系统中转换器电流的均衡分布,降低转换器承受的电、热应力,提高系统可靠性,给出一种采用自动主从控制策略的均流方案,并给出了方案实现的关键部件--均流控制芯片的设计.设计中采用电流反馈环路对输出电压进行调整,降低了PCB板级寄生效应对调整信号的影响;并提出一种启动控制电路用以改善系统的启动时序,加速了启动阶段的电流均衡过程.芯片采用1.5μm BCD(Bipolar-CMOS-DMOS)工艺设计实现,面积为3.6mm2.应用该芯片构成了一个由两个直流转换器组成,具有12V/3A输出能力的并行电源系统.测试结果表明,该并行电源系统满负载时均流误差小于1%.     

片上互连的发展趋势

目前集成电路设计方法学的主要目标已经从如何减少芯片面积转变到如何提高设计效率。片上互连作为基于平台的SoC(片上系统)设计方法学的核心部件越来越受到重视。回顾了PC架构总线的发展历史,认为串行、分层和采用数据协议是此类计算机系统互连发展的方向;分析了现有的两种具有代表性的片上总线,认为简单、灵活、低功耗是片上互连的特点,指出现有片上总线在全局同步时钟、数据吞吐量等方面的问题。最后介绍了片上网络提出的背景、现有成果及发展方向。     

大规模集成电路相关测试标准的剖析

集成电路测试是保证集成电路质量、发展的关键手段.CMOS器件进入超深亚微米阶段,集成电路继续向高集成度、高速度、低功耗发展,使得IC在测试和可测试性设计上都面临新的挑战.重点研究了纯数字信号、混合信号和片上系统测试的一些问题和相关标准,包括IEEE 1149.1-1990到IEEE 1149.6-2003,IEEE 1450,IEEE 1500,IEEE-ISTO Nexus 5001等测试标准.总结了集成电路测试标准的特点和最新进展,分析了这些标准在实际应用中存在的一些问题及其局限性,并对今后集成电路测试技术标准的发展给出了预测.     

数/模混合信号设计验证中主要问题的分析

数/模混合片上系统的发展日新月异,为保证产品良率,芯片投片前的验证是片上系统设计流程中的关键环节.在数/模混合信号验证方法中,如何对整个混合信号设计的数字模块和模拟模块进行划分,以及如何完成两类模块间数字信号和模拟信号的相互映射传输,是混合验证中的两个主要问题.以一个1∶2解复用的混合信号设计为例,对这两个问题进行了分析讨论,同时从工具角度对两类仿真器之间的同步做了论述,最后采用Cadence的Virtuoso AMS Simulator工具进行了完整的混合信号验证.     

“小白礁Ⅰ号”清代木质沉船构件的脱盐监测

“小白礁Ⅰ号”是一艘沉没于清代道光(1821-1850)年间的远洋木质商船,其“中西合璧”的船体构造为社会所关注。脱盐保护处理主要采用10 mmol·L-1 EDTA-2Na为水溶液,NaOH配置成中性后,静水浸泡和去离子水循环相配合,周期性更换脱盐溶液的方式进行。选取浸泡脱盐中的“小白礁Ⅰ号”典型船体构件作为持续监测观察样本,定期采集脱盐浸泡液样品,通过连续为期一年的分析检测,全面监控评估船体构件的脱盐情况。利用分光测色计检测木材样品表面颜色变化;扫描电镜-能谱（SEM-EDS）观察木材样品微观形貌及元素变化;元素分析仪检测木材样品的硫元素含量、电感耦合等离子体质谱仪（ICP-MS）检测脱盐溶液的铁元素含量,评估以硫铁化合物为主的难溶盐脱除效果;离子色谱分析（IC）检测脱盐溶液中的阴阳离子含量,评估可溶盐的脱除效果。分光测色计测试结果表明,“小白礁Ⅰ号”船体构件整体的色差变化趋势较为稳定,色差变化不明显。扫描电镜-能谱（SEM-EDS）测试结果表明,以球状颗粒形态存在的硫铁化合物明显减少,难溶盐得到了有效的脱除。元素分析仪、电感耦合等离子体质谱仪（ICP-MS）测试结果表明,船体构件中硫含量降低到1 Wt%左右,脱盐溶液内的铁元素含量整体偏低,波动幅度不明显,且呈缓慢的下降趋势,后半段铁元素脱除率明显降低。离子色谱分析（IC）结果表明脱盐溶液中SO2-₄含量很低,变化小。K+,Mg2+和Ca2+已经基本检测不到。Cl-和Na+含量相对较高,是由脱盐试剂中含有这两种离子所致,停止投放试剂改换纯水浸泡可有效降低含量。Cl-和Na+含量虽然有所波动,但在长达一年的时间内总脱盐量变化幅度较小,大量可溶盐已被脱除。     

离子色谱法测定烟气脱硫石膏中半水亚硫酸钙的含量

用离子色谱法测定了烟气脱硫石膏中亚硫酸根的含量,并以此换算成半水亚硫酸钙的质量分数。半水亚硫酸钙在盐酸和氯化亚锡溶液中转化为二氧化硫,二氧化硫被吸收液吸收。吸收液经0.22μm的滤膜过滤后,分取25μL进样,经AS9-HC型分离柱和AG9-HC型保护柱分离,以8mmol·L-1碳酸钠-2mmol·L-1碳酸氢钠溶液为流动相进行淋洗,采用电导检测器进行检测。亚硫酸盐的质量浓度在1.00~100mg·L-1范围内与其峰面积呈线性关系,检出限(3S/N)为0.05mg·L-1。以烟气脱硫石膏样品为基体进行加标回收试验,所得回收率为97.4%和101%,测定值的相对标准偏差(n=6)在0.35%~1.4%之间。     

Recent Development of Advanced Functional Polymers for Semiconductor Encapsulants of Integrated Circuit Chips and High-temperature Photoresist for Electronic Applications

A new polymer system of semiconductor devices was studied in response to the multifunctional systems evolved. A variety of functional polymers have been developed in the manufacture of semiconductor and integrated circuit (IC) packaging devices by R&D of high-temperature polymers. With the increase in integration of electronic devices and the need to reduce overall size, market needs are moving to multilevel metallization. Toray's core polymer technologies for electronic devices in the past 35 years (1961–95) are reviewed. The new technology of IC encapsulants of biphenyl type epoxy compounds is described for the new generation 16 megabits dynamic randon accessory memory (DRAM) electronic memory device, with good heat dissipation characteristics and low stress with an anti-flammability UL V-0 property of halogen-free formulation. As core functions are built into devices, packaging and mount technologies become more important. A new photosensitive high-temperature polymer stable up to 500°C with photosensitivity and high resolution has been developed. The trend toward a high degree of integration in solid-state technology requires the use of new high-temperature photosensitive insulating materials. Toray's "Photoneece" system provides such versatile polyimide pattern-generation techniques, containing a unique photosensitive polyimide precursor which can be spun or coated on the substrate. The main components of polyimide consist of poly(amic acid), a tertiary amine having methacrloyl group and a sensitizer. Through analyses of visible, fluorescence and electron spin resonance (ESR) spectroscopy, and flash photolysis and quantitative analyses, a new reaction mechanism is proposed. By photo-irradiation, the stable ion radical is formed without vinyl radical polymerization. The polymer is excited to form an excited singlet state. An anion radical of pyromellitic diamide moiety in a polymer chain is generated after intersystem crossing to an excited triplet state. The resultant relief of the photosensitive polyimide precursor, after exposure to UV light with a mask, development and cure processing, is transformed into a cyclized aromatic polyimide. The new system has higher photosensitivity and resolution and eliminates three steps in the conventional pattern-making process for integrated circuits, resulting in a significant cost reduction. The characterization of pattern generation, the conversion to polyimide patterns, and the properties of both Photoneece and the patterns are discussed. Initial photoreaction of an ionic-bonded photosensitive polyimide was studied by fluorescence, ESR and flush photolysis. A charge transfer complex between a polyamic acid (polyimide precursor) and an aromatic amine (sensitizer) was formed by UV irradiation from fluorescence measurement. Photo-induced radical was observed by ESR measurement. The photo-induced radical was an anion radical of polyamic acid from flush photolysis. From these results, a new photo-induced charge separation in an ionic bonded photosensitive polyimide film was found. Photo-induced electron transfer from an aromatic amine (sensitizer) to acid part of the polyamic acid occurs. © 1997 John Wiley & Sons, Ltd.     

H.264的可编程解码器芯片研究

比较了目前H.264编码解码芯片的各种方案,介绍了基于可编程方案的H.264解码芯片及应用电路,并提出了选用多媒体芯片的策略.     

低功耗2.4GHz 0.18μm CMOS全集成低噪声放大器设计

我们利用0.18μm CM O S工艺设计了低噪声放大器。所有电感采用片上螺旋电感,全集成在单个芯片上,并实现片内50Ω匹配。本次电路设计分析采用ADS仿真软件,电源电压1V,工作电流8mA,增益为15.4dB,噪声系数2.7dB,线性度指标IIP 3为-0.6dB。结论是CM O S工艺在工艺和模型方面的改进,使得CM O S RF电路设计更为精确,可集成度更高。