多层印制电路板网印内埋电阻技术研究

利用网印导电碳浆的方法制作电阻,通过层压工艺实现电阻在多层印制电路板中的内埋.研究了导电碳浆的固化温度及固化时间与电阻值的关系,分析了导电碳浆固化程度及棕化后烘板对层压工艺可靠性的影响,测试了高温高湿与冷热冲击对内埋电阻阻值稳定性的影响.结果表明:导电碳浆固化条件选择固化温度170℃,固化时间4h,以及棕化后105℃烘...     

在挠性印制板中埋嵌无源和有源元件

文章介绍了在挠性印制板中埋嵌无源和有源元件的方法。通过化学镀Ni(P)电阻可以实现薄膜电阻的埋嵌,并能保证一定的弯折性。通过对芯片进行背面减薄和倒装连接,可以实现有源芯片的埋嵌。随后还对埋嵌元件的可靠性进行了测试。     

聚四氟乙烯平面埋电阻台阶式多层板制造技术研究

目前来说,通讯用陶瓷粉填充、玻璃短纤维增强的聚四氟乙烯微波多层印制电路板的制造技术越来越显现出其重要性,文中对平面电阻印制板的制造工艺流程进行了简单的介绍,对聚四氟乙烯埋电阻台阶式多层微波印制板制造所采用的工艺技术进行了较为详细的论述。     

埋电阻台阶式多层微波印制板制造技术研究

目前来说,通讯用陶瓷粉填充、玻璃短纤维增强的聚四氟乙烯微波多层印制电路板的制造技术越来越显现出其重要性,对平面电阻印制板的制造工艺流程进行了简单的介绍,对埋电阻台阶式多层微波印制板制造所采用的工艺技术进行了较为详细的论述.     

埋平面电阻印制电路板制造工艺探讨

本文对埋平面电阻印制板的制造工艺流程进行了简单的介绍，对所采用的工艺技术的有效性进行了较为详细的论述。     

埋嵌平面电阻印制板阻值控制方法研究

埋嵌平面电阻印制板是一种通过将具有平面型电阻材料埋置到印制线路板中,从而使印制线路板同时具有连接各元器件和普通分立电阻元器件才有的电阻功能。而如何控制埋嵌平面电阻阻值的大小以符合设计要求,是制造过程中核心技术。从原理、设计计算、制程控制各方面来全面分析埋嵌平面电阻阻值的控制方法,以供业界分享。     

PTFE埋电阻多层印制板制造技术

随着电子产品技术的发展,无源器件集成技术与聚四氟乙烯(PTFE)材料在多层印制电路板制造中扮演着越为重要的角色。论文在无源器件集成技术之一的薄膜埋电阻技术的基础上对PTFE埋薄膜电阻多层印制板制造工艺过程进行了讨论。     

内埋电阻

本文讨论了将固定电阻浆料用丝网印刷方法制造内埋电阻的过程。     

集成元件印制板技术

集成元件印制板是把无源元件(如电阻、电容和电感)分别或综合集成到PCB(印制板)内层而形成的,它是新一代HDI/BUM板发展的一个重要方面,并且随着集成电路(IC)的高集成化、高频信号和高速数字信号传输的发展,要求印制板有更好的特性阻抗和更小的电磁干扰,采用集成元件印制板既能提高印制板的高密性又能达到更好的特性阻抗匹配和更小的电磁干扰.介绍了集成电容印制板和集成电阻印制板的材料及工艺过程.     

电阻温度系数研究及其在可靠性早期监测中的应用

在大规模集成电路进入深亚微米时代的同时,金属互连层在产品的可靠性方面扮演着越来越重要的角色,因此,需要对金属层进行快速的在线监测。本文对电阻温度系数的内在物理含义进行了详细论述,讨论了电阻温度系数与金属电迁移可靠性失效时间的关系,指出电阻温度系数是一个可以表征金属可靠性的敏感参数,可以用来对金属可靠性进行早期评估与在线快速监测。同时讨论了金属层测试结构的几何尺寸对电阻温度系数的影响,指出了运用电阻温度系数进行早期可靠性在线监测时需要避免测试结构的干扰。     

Preliminary assessment of the stability of thin- and polymer thick-film resistors embedded into printed wiring boards

Embedding passive components into multilayer printed wiring boards (PWBs) meet electronic device requirements concerning the necessity of saving the surface board area for active elements, reducing board’s size, improving device functionality and safety as well as overall product cost reduction. Since embedded components cannot be replaced after the board is completed, a long term stability and reliability are the important concerns for manufactures.This paper presents the results of examinations of embedded thin-film NiP resistors and polymer thick-film resistors during their continuous operation and the influence of temperature on the resistance values after the simulation of a lead-free soldering process and after the temperature cycling test (?40 ?C/+85 ?C).     

有机基板中埋入无源元件概述

介绍了埋入无源元件在减小基板面积和提高基板高频特性的优点,总结了目前正在应用和研究的埋入电阻和埋入电容技术的实现方法.并提出基于埋入平面薄膜电阻和埋入薄芯介质材料形成平面电容技术的混合埋入技术将成为未来埋入无源元件PCB的主流技术.最后阐述了埋入无源元件技术在产业化过程中遇到的困难.     

Environmental Qualification Testing and Failure Analysis of Embedded Resistors

Embedding passive components (capacitors, resistors, and inductors) within printed wiring boards (PWBs) is one of a series of technology advances enabling performance increases, size and weight reductions, and potentially economic advantages in electronic systems. This paper explores the reliability testing and subsequent failure analysis for laser-trimmed Gould subtractive nickel chromium and MacDermid additive nickel phosphorous embedded resistor technologies within a PWB. Laser-trimmed resistors that have been “reworked” using an inkjet printing process to add material to their surface to reduce resistance have also been considered. Environmental qualification testing performed included: thermal characterization, stabilization bake, temperature cycling, thermal shock and temperature/humidity aging. In addition, a pre/post-lamination analysis was performed to determine the effects of the board manufacturing process on the embedded resistors. A failure analysis consisting of optical inspection, scanning acoustic microscope (SAM) and environmental scanning electron microscope (ESEM) imaging, and PWB cross-sectioning was employed to determine failure mechanisms. All the embedded resistors were trimmed and the test samples included resistors fabricated both parallel and perpendicular to the weave of the board dielectric material. Material stability assessment and a comparison with discrete resistor technologies was performed.     

Structural and electrical properties of stable ni/cr thin films

The electrical and structural properties of nickel-chrome (NiCr) thin film resistors were studied for the effect of post-deposition annealing on stability. The temperature coefficient of resistance (TCR) of sheet resistivities in the range of 100 to 200 Ω/□ could be improved by both air and vacuum annealing to achieve 5 ± 5 ppm/°C over the temperature range of -180° C to +100° C. With stability tests, air annealing proved to be more favorable for stable TCR. Studies via SIMS and ESCA identified surface segregation of Cr whereas TEM micrographs revealed correlating structural transformation of the films upon annealing. An intentional impurity, Si, played an important role in achieving a low TCR.     

新型聚酰亚胺多层印制电路板可靠性研究

随着电子产品向着更小更轻薄,且功能更强大的方向发展,各种类型的高密度电路板应运而生。“全聚酰亚胺IVH结构”多层电路板成为下一代电路板的候选,该类电路板由聚酰亚胺薄膜一次压合而成,与传统的玻璃布树脂板相比有以下特点：厚度薄（六层板厚小于300μm）、低介电常数、无卤、高阻燃。其另一特点是其内部互联结构,实现各金属层间互联的过孔由激光钻产生,并填入特殊导电胶。文章考察了高低温冲击实验（-25℃／125℃）过程中孔电阻更化情况,并通过数值模拟进行了验证。     

电路板焊点在工程环境条件下寿命分析

在电子设备寿命周期中．要经历各种环境载荷。我们需要综合号虑载荷对电子设备可靠性和寿命的影响。在该文中．以一块电路板为案例。建立整板模型．然后设定边界、分别加载温度和随机振动载荷。并利用有限元分析工具ANSYS计算,得出应力应变云值。最后基于Coffin—Manson疲劳寿命模型和线性叠加模型,分析和预测热循环和随机振动条件下．器件焊点疲劳寿命,为整板器件可靠性设计提供参考,     

9位芘和长链烷氧基苯取代的三联芴

采用Suzuki偶联反应制备了9位芘和长链烷氧基苯取代的三联芴ATF。热分析结果显示ATF具有良好的热稳定性,其热分解温度为430℃,玻璃化转变温度高达155℃。芘在芴9位的非共轭取代并没有改变共轭三联芴的高效率蓝光发射特点,但ATF的HOMO能级得以明显提高,这意味着空穴注入性能有明显的提高。ATF既可以采用真空蒸镀,又可以采用溶液旋涂的方法制备电致发光器件,旋涂器件（ITO/PEDOT：PSS（40nm）／ATF（100nm）／Ba／Al）的启动电压为7V,最大外量子效率为0．62。     

Microstructure and electrical properties of ‘pre-sintered bismuth ruthenate-glass composite’ based thick film paste for resistor application

Thick film resistors based on a bismuth ruthenium oxide (BRO) and a leadborosilicate glass have been used to study the effect of a ‘pre-sintered glass–ceramic composite’ powder in the paste preparation on the resistor characteristics. Pre-sintered glass–ceramic composite was prepared by heating a physical admixture of leadborosilicate glass frit and BRO as functional material at various temperatures above the softening point of the glass. The microstructural changes associated with ‘pre-sintering’ step were studied using scanning electron microscopy, energy dispersive X-ray analysis and X-ray diffraction, and, were correlated to the electrical characteristics of these resistors. It was observed that pre-sintering at a lower temperature of 600°C helps in restricting the agglomeration of conducting BRO particles and in generating more non-sintered contacts between them, which improves consistency in sheet resistance and hot temperature coefficient of resistance (TCR). At the same time, the pre-sintering step lowers the absolute TCR value, mostly by way of compensation of the high negative TCR of glass by the positive TCR of Pb containing ruthenate phases and/or RuO₂, which have positive TCR. It is explained that the Pb containing BRO phases are formed in situ through the Bi???Pb exchange reaction. The pre-sintering temperature of 600°C was, thus, found to be optimum for the present processing conditions.     

埋入式电阻的热特性研究

通过对电阻的热功率、表面积的分析,研究了PCB板中的埋入式电阻的热特性,给出了PCB板中埋入式电阻的温升的解析表达式。计算了埋入式电阻在PCB板中的不同位置的温升情况,详细讨论了多个埋入式电阻的温升与单个电阻温升的关系,得到了计算具有多个埋入式电阻的PCB板的温升的方法。在设计PCB板时,大功率埋入式电阻应安排在板的中部,埋入式电阻的相互距离要分散并远离PCB板表面。     

The effect of power cycling on the reliability of lead-free surfacemount assemblies

A power cycling in-test monitoring system has been constructed to test the reliability of eight different lead-free surface mount assemblies. The assemblies included SnAg3.8Cu0.7 and SnAg3.8Cu0.7X solder joints on OSP-Cu (organic solderability preservative on Cu), electroless NiAu, immersion Ag and immersion Sn board metallizations. One Pb containing assembly, Sn62PbAg2 on OSP-Cu board metallization, was included for comparison. The components on the assemblies were 1206 resistors (Sn100 metallization on the end terminals) and 100 lead QFP with gullwing leads (SnPb15 metallization). All assemblies experienced up to 5000 power cycles of ambient to 100°C with a 15 min dwell at each temperature. Solder joint reliability was evaluated by monitoring electrical resistance after each power cycle and examining mechanical strength and microstructure with number of power cycles. The 1206 resistors on four of the assemblies (one of which was the Pb containing assembly) exhibited electrical resistance increases after 4000 power cycles. All resistor samples decreased in strength by more than 70% at 5000 cycles and cracks appeared after 1000 power cycles. All gullwing lead solder joints exhibited good reliability over 5000 power cycles, with no resistance increase and no strength reduction. Small cracks appeared after 3000 power cycles