再布线圆片级封装板级跌落可靠性研究

再布线圆片级封装通过对芯片焊区的重新构造以及无源元件的集成可以进一步提升封装密度、降低封装成本。再布线圆片级封装器件广泛应用于便携式设备中,在实际的装载、运输和使用过程中抗冲击可靠性受到高度重视。按照JEDEC标准对再布线圆片级封装样品进行了板级跌落试验,首先分析了器件在基板上不同组装点位的可靠性差异;然后依次探讨了不同节距和焊球尺寸、再布线结构对器件可靠性的影响;最后,对失效样品进行剖面制样,采用数字光学显微进行形貌表征。在此基础上,结合有限元分析对再布线结构和铜凸块结构的圆片级封装的可靠性和失效机理进行深入地阐释。     

业内尺寸最小的2通道ADC

Maxim推出业内尺寸最小的2通道ADC MAX11645。该款12位I2C ADC在微型1.9 mm×2.2 mm晶片级封装(WLP)中内置基准。4×3焊球阵列、0.5 mm焊球间距便于在四层PCB上进行布局,0.64 mm的超薄外形使器件理想用于在PCB两侧放置     

圆片级封装的研究进展

圆片级封装(wafer level package,WLP)因其在形状因数、电性能、低成本等方面的优势,近年来发展迅速。概述了WLP技术近几年的主要发展。首先回顾标准WLP结构,并从焊球结构等方面对其进行了可靠性分析。其次介绍了扩散式WLP工艺以及它的典型应用,并说明了扩散式WLP存在的一些可靠性问题。最后总结了WLP技术结合硅通孔技术(TSV)在三维叠层封装中的应用。     

雷达电子装联中LGA器件的表面组装技术

雷达电子产品现在趋向于使用一些微小型的LGA器件(没有焊球的BGA)。LGA封装器件的焊接高度只有50.8μm~76.2μm,具有安装高度低的优点,因此LGA封装器件能够有效地提高板级电子组件抗跌落和抗弯曲的性能。雷达LGA电子组件还能够减小安装空间,因此具有更高的安装密度。详细介绍了LGA器件的特点,带有LGA器件的PCB的设计原则以及LGA器件详细的安装工艺和返修工艺。LGA器件的可靠性性能也进行了讨论。     

晶圆级封装技术的发展

晶圆级封装(wafer level package,WLP)具有在尺寸小、电性能优良、散热好、性价比高等方面的优势,近年来发展迅速。本文概述了WLP封装近几年的发展情况,介绍了它的工艺流程,得以发展的优势,并说明了在发展的同时,存在着一些标准化、成本、可靠性等问题,最后总结了WLP技术的发展趋势及前景。     

晶圆尺寸级封装器件的热应力及翘曲变形

晶圆尺寸级封装(WLCSP)器件的尺寸参数和材料参数都会对其可靠性产生影响。使用有限元分析软件MSCMarc,对EPS/APTOS生产的WLCSP器件在热循环条件下的热应力及翘曲变形情况进行了模拟,分析了器件中各个尺寸参数对其热应力及翘曲变形的影响。结果表明:芯片厚度、PCB厚度、BCB厚度和上焊盘高度对WLCSP的热应力影响较为明显。其中,当芯片厚度由0.25mm增加到0.60mm时,热应力增加了21.60MPa;WLCSP的翘曲变形主要受PCB厚度的影响,当PCB厚度由1.0mm增加到1.60mm时,最大翘曲量降低了20%。     

一种新颖的微电子封装:圆片级封装

本文介绍了一种当前正在快速发展的微电子器件的新颖封装－圆片级封装（WLP）的定义，主要优缺点，焊盘再分布和植球等主要工艺过程等。     

超细凸点节距WLP制备关键工艺技术研究

通过优化结构设计,改善厚胶光刻工艺条件,采用凸点真空回流等举措,解决了制备超细节距圆片级封装(WLP)工艺中遇到的技术难题,提升了WLP的工艺技术水平;并将具有更优性能的BCB材料应用于WLP的介质层,成功制备出凸点节距为90 μm和280 μm的样品.研制的样品已通过相关测试和考核.     

2009年晶圆级封装趋势

专家认为,受持续增长的移动设备和汽车应用需求的驱动,晶圆级封装（WLP）将向I／O数更高和引脚节距更小的方向发展。2009年其他需要关注的WLP趋势还包括大功率和高精度精密器件、穿透硅通孔（TSV）、扇出和嵌入式闪存。     

28 nm WLP封装中PBO结构对CPI可靠性的影响

基于28 nm晶圆级封装(WLP)工艺,研究了聚苯撑苯并噁唑(PBO)对芯片-封装交互(CPI)可靠性的影响,分析了PBO堆叠关系和边缘位置的选择对CPI可靠性的影响。仿真实测结果表明,堆叠关系和边缘位置的变化对CPI可靠性有较显著的影响,两种因素的失效机理不同。利用TCAD工具能够有效预测结构变更对CPI可靠性的影响,从而优化结构设计,提升WLP封装的CPI可靠性。     

微米级楔形微调结构

目前在大多数机械设备中，对结构进行微量调整时通常采用千分尺调节机构，但由于千分尺的精度为0.01mm，因此在进行0．001mm以上精度等级的调整时，仅利用千分尺便无法满足要求。针对这一问题，可采用将千分尺与机械结构有效结合，提供一种能够进行0．001mm以上精度调整的千分尺楔形微调结构来解决。     

Level Selection for a Level Crossing Receiver

In this paper a technique for setting the level in a levelcrossing detector is discussed. Experimental verification of this method is given along with measurements of receiver performance.     

人工神经元群的逐层学习

本文提出了人工神经元群的逐层学习方法.该方法所建议的学习过程与人类个体及社会知识的增长过程较为接近,并且可以改善网络系统的泛化能力,提高系统的学习效率.本文对一些具体问题进行计算机仿真研究。     

模块级验证环境在顶层验证中的复用

模块级验证环境在顶层验证中的复用可以有效地提高生产率,利用Synopsys先进的NTB验证语言可以方便地实现验证环境复用。本文介绍了验证环境复用的方法,并通过一个实例说明了验证环境复用的实现细节。     

面向分模块寄存器传输级结构的高层次综合方法

随着集成电路工艺技术的发展，连线延时将逐渐主导系统的性能，传统的高层次综合方法已经不能满足设计的需要。文章讨论了寄存器传输级结构对综合方法的影响，并提出使用分模块的寄存器传输级结构作为高层次综合的目标结构。针对新的结构，概括了设计流程，设计了核心算法。实验数据表明，与传统的方法相比，该方法可以有效地改善系统的性能。     

Physical Level Protocols

The physical level is the most basic protocol level in the hierarchy of data communication protocols. This level covers the physical interface between devices and the rules by which bits are passed from one to another. These devices may be, for example, a data terminal equipment (DTE) and a data circuit-terminating equipment (DCE, e.g., a modem). This paper describes the physical level and the national and international standards that have been developed for this level. Included are insights into the development of recently adopted physical level protocols.     

有线电视放大器的最大输出电平和标称输出电平

全面分析有线电视放大器最大输出电平Somax和标称输出电平Sa的差别，说明基于两种输出电平的两类放大器输出电平计算公式的适用条件和适用时期，指出当前不能继续使用基于最大输出电平的计算公式，必须采用基于标称输出电平的系统满载计算公式来设计计算放大器输出电平。     

Automatic Generation of System Level Assertions from Transaction Level Models

We automatically generate assertions from Transaction Level Model (TLM) simulation traces. The generated assertions express design specifications in the form of linear temporal logic with quantitative temporal constraints [4]. We first generate the assertions without regard to the quantitative time constraints. They are mined in the form of frequent patterns in the simulation traces. We mine simulation traces using episode mining to identify frequent episodes comprising function calls and events. We then annotate the episodes with real time parameters to express quantitative time constraints among the function calls or events in the episode. When mining such TLM assertions, we employ symbolic execution to generalize the parameters and return values of function calls in the traces to help the mining engine generate high quality assertions. We have constructed a realistic AXI-based interconnection network platform that we demonstrate experimental results on. We show that our technique efficiently generates high quality performance and functional assertions on the AXI-based platform as well as a transaction level AMBA-based DMA controller. We demonstrate that episode mining is more scalable and able to generate a more compact set of high quality TLM assertions than previous efforts using sequential pattern mining. The number of generated assertions using episode mining can be reduced by up to 228 times, and the time interval between two events/function calls in each assertion is smaller than 50 time units.     

DCNA Higher Level Protocols

This paper explains a philosophy for modeling the higher level communication functions into a network architecture for heterogeneous computer networks called Data Communication Network Architecture (DCNA), the logical structure of the architecture, and several protocols based on it. To specify higher level protocols among computers of different types, DCNA defines a logical model of a computer network consisting of three submodels: the basic model, the logical network model, and the virtual network model. The basic model represents a logical view of the network resources, e.g., processing power, files, data bases, I/O devices, and a layered structure for the basic mechanisms for accessing such resources, which incorporate the concept of sublevels as well as levels. The logical network model describes the mechanisms for unified management of network resources. The virtual network model describes the mechanisms for using network resources. The. common use of network resources, by several sets of interrelated applications is made easier by treating the logical network and the virtual network separately. These models form the basis for the stipulation of higher level protocols, such as network management protocols, message transfer protocols, virtual terminal protocols, and virtual file system protocols.