封装器件多应力叠加失效仿真分析与验证

针对某双列直插式(DIP)封装器件在整机温循试验中出现的失效现象,分析在器件与电路板焊接环节、电路板与整机装配环节和整机温循试验环节3个工况下可能的失效原因,对原因分别进行单工况和多工况的失效仿真分析。针对不同仿真模型在不同工况下的叠加仿真难题,提出基于ANSYS Workbench有限元软件的多应力叠加仿真方法,对比单一工况和多种工况下的仿真结果。结果表明,DIP封装器件失效是器件在焊接尺寸不匹配、过定位装配和温循试验三种工况下,机械应力和热应力的叠加使玻璃绝缘子产生裂纹导致的,有限元仿真结果与实验结果基本吻合,为DIP封装器件在多工况下应力叠加失效的故障机理研究提供一种可参考的仿真方法。     

高多层超长高速背板工艺研究

相比常规高多层背板而言,超长背板的尺寸稳定性较难控制,孔到线距离越来越小,层间对准度要求越高。文章主要介绍一种34层超长板的关键制作工艺,包括涨缩的管控,层间对准度的控制,背钻堵孔的改善,阻抗的控制等,为重点关键流程提供制作方法及解决方案。     

不同钝化层对硅基铝金属膜应力影响的研究

采用光偏振相移干涉原理测量了硅基上不同钝化层下铝膜应力的变化.研究表明:不同的钝化层对铝膜的应力影响不同.SiO2钝化层下的铝膜应力最小,而钝化层为聚酰亚胺的铝膜应力最大.200 ℃下退火4 h后,应力减小明显,且分布趋向均匀.同时采用有限元法对不同钝化层的铝膜进行了应力模拟,模拟结果与实验结果相符.     

一种应用于电子封装的热匹配工艺设计

作为组件封装材料,铝合金与芯片和电路基板之间存在热膨胀不匹配问题.采用热匹配工艺设计,选择合适的热匹配材料,为铝合金盒体与LTCC基板热膨胀匹配提供了一种理想解决方案.根据匹配设计理念,利用Abaqus有限元软件对热匹配材料及铝盒体的结构进行了仿真和优化,并与加工出试验样品的测试结果进行了对比,验证了模拟结果,为铝合金...     

系统HDI金属化阶梯板的研究和开发

在对系统HDI、混压阶梯板、控深铣、激光钻孔等PCB制作技术重点分析的基础上,设计了新的制作流程,实现了系统HDI板与金属化阶梯制作的集成,从而开发出了可应用于焊接各类功能模块的系统HDI金属化阶梯板。     

300mm硅片CMP设备装载技术研究

定位装载机构是硅片化学机械抛光（CMP）设备的一个重要组成部分。本文通过对目前CMP设备中硅片定位装载机构的介绍、分析与比较,介绍了一种新型定位装载机构的功能、结构原理及控制原理,并最终通过在工艺试验中的实际应用确定了该机构已基本达到设计要求。     

车路互联网的底层协议-802．11p标准

详细地描述了车路互联网系统的底层协议-802．11p标准。将802．11p与传统无线局域网技术进行对比,分析了802．11p在媒体接入控制层（MAC）与物理层（PHY）所做的修改,并从物理层参数、PP—DU帧结构,以及接人优先级等多方面指出了802．11p能在高速移动环境下建立稳定通信链路的原因。其次,还对802．11p所采用的频段、信道、发射功率以及频谱掩模进行分析;最后提出了802．11p在仿真方面所面临的挑战,并且在Simulink上建立了一套动态仿真系统,对标准进行仿真验证。     

基于数学建模要求下先进的提拉法控制系统研制

提出了在开发一种先进的直拉法晶体生长控制系统中占据重要地位的设备及工艺特征的下位机模型;分析所采集到的实验数据,揭示出控制中的重要问题,由此开发了一种新的控制结构;该模型是建立在常规控制结构和提出新的控制结构性能对比的基础上。     

Electrical instability in short channel organic thin-film transistors induced by lucky-polaron mechanism

In this work we study the electrical stability under both gate bias stress and gate and drain bias stress of short channel (L = 5 μm) bottom contact/top gate OTFTs made on flexible substrate with solution-processed organic semiconductor and fluoropolymer gate dielectric. These devices show high field-effect mobility (μ_FE> 1 cm²V⁻¹s⁻¹) and excellent stability under gate bias stress (bias stress V_ds = 0V). However, after prolonged bias stress performed at high drain voltage, V_ds, the transfer characteristics show a decreased threshold voltage, degradation of the subthreshold slope and an apparent increase in the field effect mobility. Furthermore, the output characteristics show an asymmetry when measured in forward and reverse mode. These experimental results can be explained considering that the bias stress induces the damage of a small part of the device channel, localized close to the source contact. The analysis of the experimental data through 2D numerical simulations supports this explanation showing that the electrical characteristics after bias stress at high V_ds can be reproduced considering the creation of donor-like interface states and trapping of positive charge into the gate dielectric at the source end of the device channel. In order to explain this degradation mechanism, we suggest a new physical model that, assuming holes injection from the source contact into the channel in bounded polarons, envisages the defect creation at the interface near the source end of the channel induced by injection of holes that gained energy from both the high longitudinal electric fields and the polaron dissolution.     

Chemisorption sensing and analysis using silicon cantilever sensor based on n-type metal-oxide-semiconductor transistor

This paper presents a silicon cantilever sensor based on n-type metal-oxide-semiconductor transistor for chemical sensing and analysis using the chemisorption-induced surface stress sensing principle. The cantilever is along the 〈1 0 0〉 crystal orientation of the (1 0 0) silicon, and the transistor channel is parallel to as well as located at the rear part of the cantilever to obtain high stress sensitivity. The gold film deposited on the bottom surfaces of cantilevers is chemically functionalized with a self-assembled monolayer of 4-mercaptobenzoic acid via the Au-SH covalent bonding. The vapor phase chemical sensing experiments with acetone, ethanol, nitroethane and water vapor as targets are performed. The observed response differentiation implies that the molecular interaction mechanisms between different chemical molecules are different.