塑封集成电路分层研究

目前塑封集成电路的分层问题越来越受到半导体集成电路封装厂商以及整机厂商的关注和重视。文章对塑封集成电路的分层产生的机理和塑封表面贴装集成电路潮湿敏感度等级的认定作了介绍。另外,对几种主要的分层失效的标准作了详细解释和说明。文章对影响塑封表面贴装集成电路分层的主要因素进行了详细的分析和说明,并对三种不同封装形式塑封集成电路的吸湿和去湿过程进行了分析和研究,并给出了结论。最后文章就如何防止分层问题提出了相应的措施。     

基于封装工艺识别翻新塑封集成电路

塑封集成电路在高可靠性领域应用越来越广泛,国内已有相当数量的塑封集成电路应用于国防领域。但是,目前大部分关键塑封集成电路依赖进口,采购渠道不是很通畅,市场中存在大量的翻新件。文章基于塑封集成电路封装工艺,简要介绍如何识别翻新塑封集成电路。     

基于GJB7400的军用塑封集成电路检验标准探讨

塑封集成电路凭借其五大优势,势必会在军用集成电路发展之路上大有作为.目前我国军用塑封集成电路正在处于高速发展阶段,提高其可靠性是军用塑封集成电路发展的重要任务.为加强军用集成电路质量控制,制定了GJB7400-2011《合格制造厂认证用半导体集成电路通用规范》,是军用塑封集成电路筛选检验的主要标准.通过梳理GJB740...     

塑封器件的贮存环境与使用可靠性

介绍了用潮热环境试验模拟塑封器件在长期贮存时对水汽的吸附以及用潮热试验和焊接热的综合影响来评价塑封器件耐潮湿性能的方法.     

塑封混合集成电路超声检测标准探讨

塑封集成电路具有成本低、重量轻等优点,在军用等高可靠领域越来越受到重视。超声检测技术是一种无损的检测手段,广泛用于检测塑封电路中的分层、裂纹、空洞等缺陷。目前超声检测的标准主要是针对塑封单片集成电路,而塑封混合集成电路与塑封单片集成电路的结构存在差异,现行超声检测标准不完全适用于混合塑封集成电路,对检测结果判定存在差异。该文探讨塑封混合集成电路的超声检测内容和判剧,为塑封混合集成电路的超声检测提供借鉴。     

塑封集成电路离层对可靠性的影响及解决方法

塑封集成电路因其是非气密性封装,封装材料热膨胀系数的不同以及被粘接材料表面能低,是造成塑封电路离层或开裂的内部原因。通过选择特殊的封装材料（特别是框架材料）和工艺可以解决离层或开裂问题,大大提高塑封集成电路的稳定性和可靠性。水汽是造成塑封集成电路离层或开裂的外部原因,可以通过驱除和防潮措施来解决。要提升塑封集成电路可靠性,必须从技术和工艺上解决塑封电路离层或开裂问题。我们在这方面做了有益的尝试,取得了良好的效果,为拓展塑封集成电路的应用领域创造了条件。     

提高厚膜混合集成电路产品的一次塑封合格率

本文从厚膜混合集成电路产品塑封不合格品产生的原因分析入手，结合厚膜混合集成电路的工艺特点，采用过程质量统计分析方法，给出提高厚膜混合集成电路产品一次塑封合格率的方法。     

贯彻国军标产品封装问题探讨

简要介绍了厚膜混合集成电路（ＨＩＣ）贯彻国军标用金属管不汽含量和盐雾试验３的现状，重点探讨了半导体集成电路（ＳＩＣ）贯军标塑封的可靠性、塑封材料的吸水性、热膨胀系数和模化合物的组份等。     

集成电路封装的打开技术

本文系统介绍了集成电路封装的打开技术，着重介绍了塑封集成电路的部分打开和全部打开，并对打开过程中出现的问题作了分析和探讨。     

塑封器件回流焊与分层的研究

由于无铅焊料的应用,回流焊的温度提高影响了塑封器件的质量和可靠性。针对实际的LQFP器件,利用有限元软件建立三维模型,分析了塑封器件在潮湿环境中的湿气扩散及回流焊中的形变和热应力分布,并讨论了塑封料参数及细小裂纹对分层的影响。结果表明,在湿热的加载下,塑封器件的顶角易发生翘曲现象;芯片与塑封料界面处易分层,导致器件失效。     

Moisture resistance of SU-8 and KMPR as structural material

This paper treats the moisture resistance of SU-8 and KMPR, two photoresists considered as structural material in microsystems. Our experiments focus on the moisture resistance of newly developed radiation imaging detectors containing these resists. Since these microsystems will be used unpackaged, they are susceptible to all kinds of environmental conditions. Already after 1 day of exposure to a humid condition the structural integrity and adhesion of SU-8 structures, measured by a shear test is drastically reduced. KMPR photoresist shows much stronger moisture resistance properties, making it a suitable alternative in our application.     

Three-dimensional interconnect with excellent moisture resistance for low-cost MMICs

The moisture resistance of three-dimensional (3-D) interconnects using organic insulator films and Au metals has been investigated to ascertain the feasibility of housing monolithic-microwave integrated circuits with these interconnects in inexpensive nonhermetic packages. By comparing polyimide and benzocyclobutene (BCB) for organic insulator films, it was found that although polyimide has higher moisture absorption than BCB, it has a greater moisture resistance. This suggests that moisture absorption is not the dominant factor in moisture resistance and that BCB has higher water permeability than polyimide. As an adhesion layer between Au metal and insulator film, W and WN have better moisture resistance than WSi and WSiN; adhesion layer compositions containing Si oxidize easily. Further, the metal patterning method has an effect on moisture resistance in terms of leakage current. Reactive ion etching (RIE) with SF/sub 6/ gas is necessary in order to completely remove the metal atom residue left after ion milling with Ar gas. An interconnect using polyimide insulator film, W or WN adhesion metal, and metal patterned by ion milling and RIE, did not fail in terms of contact resistance and leakage current under stress of 85/spl deg/C and 85% relative humidity with a bias for 1000 h.     

Development of conductive adhesives for solder replacement

Develops conductive adhesives with stable contact resistance and desirable impact performance. Effects of purity of the resins and moisture absorption on contact resistance are investigated. Several different additives (oxygen scavengers and corrosion inhibitors) on contact resistance stability during elevated temperature and humidity aging are studied, and effective additives are identified. Then, several rubber-modified epoxy resins and two synthesized epoxide-terminated polyurethane resins are introduced into ECA formulations to determine their effects on impact strength. The loss factor, tan δ, of each formulation is measured using a dynamic mechanical analyzer (DMA) and impact strength is evaluated using the National Center for Manufacturing Science (NCMS) standard drop test procedure. Finally, high performance conductive adhesives are formulated by combining the modified resins and the effective additives. It is found that 1) purity of the resins and moisture absorption of the formulation affect the contact resistance stability of an ECA; 2) the oxygen scavengers and corrosion inhibitors can delay contact resistance shift; 3) one of the corrosion inhibitors is very effective in stabilizing the contact resistance; 4) some rubber-modified epoxy resins and the epoxide-terminated polyurethane resins can provide the conductive adhesives with superior impact performance; and 5) conductive adhesives with stable contact resistance and desirable impact performance are developed     

Adhesion improvement of thermoplastic isotropically conductive adhesive

Generally, isotropically conductive adhesive formulations include epoxy resin as the polymeric matrix. Although epoxy has superior adhesion capability, its drawbacks include the tendency to absorb moisture and lack of reworkability (thermosetting polymer). In this study, a thermoplastic polymer with low moisture absorption (0.28 wt%), called polyarylene ether (PAE2), is used in isotropically conductive adhesive (ICA) formulation. Previous research work by Lu et al. showed that the moisture absorbed into epoxy caused galvanic corrosion, which result in the formation of metal oxide . By using a polymer with low moisture absorption, the amount of water present in ICA will be small, and the corrosion rate and formation of metal oxide can be reduced. However, previous measurements of contact resistance stability of PAE2-based ICA showed that they are not stable on all surface finishes. It was determined that for thermoplastic-based ICA, poor adhesion was the main mechanism for unstable contact resistance. Two methods of adhesion improvement will be evaluated in this work. The first is to use coupling agents and the second is to blend the thermoplastic with epoxy. Both methods showed promise in improving the contact resistance stability of polyarylene ether based ICA.     

PCB阻焊膜的功能

阻焊膜不仅起着阻焊作用,而且还起着防腐蚀、防潮湿和防霉菌的作用。     

集成电路陶瓷外壳析出物失效模式分析

为了集成电路的可靠性保证,往往需要对集成电路外壳进行验收。验收项目中,有一个耐湿试验分组,用来加速评定外壳的抗腐蚀性能及相应的质量可靠性能。在该试验分组中发现,陶瓷外壳失效除了已有的常规模式外,还有一种很严重的析出物失效模式。发现焊框与陶瓷结合处有胶体状析出物,析出物以流质状态析出,然后凝固,严重的还会造成焊框漏气,从而引起外壳失效。     

A study of contact resistance of conductive adhesives based onanhydride-cured epoxy systems

Electrically conductive adhesives (ECAs) are an environmentally friendly alternative to tin/lead (Sn/Pb) solders in electronics packaging applications. However, current conductive technology is still in its infancy and limitations do exist. One of the critical reliability issues is that contact resistance of silver flake-filled ECAs on nonnoble metals increases in elevated temperature and humidity environments. The main objective of this study is to investigate the contact resistance behaviors of a class of conductive adhesives, which are based on anhydride-cured epoxy systems. Curing profiles, moisture pickup, and shifts of contact resistance of the ECAs on a nonnoble metal, tin/lead (Sn/Pb), during aging are investigated. Also, two corrosion inhibitors are employed to stabilize the contact resistance. The effects of these corrosion inhibitors on contact resistance are compared. It is found that: (1) this class of ECAs shows low moisture absorption, (2) the contact resistance of the ECAs on Sn/Pb decreases first and then increases slowly during 85°C/85% relative humidity (RH) aging, (3) one of corrosion inhibitors is very effective to stabilize contact resistance of these ECAs on Sn/Pb, and (4) the corrosion inhibitor stabilizes contact resistance through adsorption on Sn/Pb surfaces. From this study, it can be concluded that ECAs based on anhydride cured epoxy systems are promising formulations for electronics packaging applications     

环氧树脂在电子封装中的应用及发展方向

介绍了环氧树脂在电子封装中的应用;环氧树脂的特点(收缩率小,耐热性好,密封性及电绝缘性优良,适用性好等)以及国外对其的技术改造(低粘度化,提高耐热性,降低吸水率)。     

绿色IC的可靠性综合评价方法

介绍什么是绿色IC产品,绿色IC产品的耐锡热能力、其引出端子的沾锡能力和锡须、吸湿敏感性评价,并给出了一些研究成果。     

Diffusion of moisture through fatigue- and aging-resistant polymer coatings on lightguide fibers

In previous work the diffusion rate of water vapor through the polymer coating on optical fiber was estimated by monitoring the strength as a function of time after suddenly changing the ambient humidity. This technique is used here to measure the diffusion of moisture both into and out of two novel fiber coatings. The first specimen is a dual-coated fiber with silica particles added to its secondary coating. It is shown that the improvement in this fiber's reliability is not due to the silica particles adsorbing/absorbing the moisture. The second fiber, coated with a fluorinated polymer, was designed to have higher fatigue resistance as a result of having a lower permeability to moisture. It is found that even though this fiber had higher than normal resistance to fatigue, the diffusion of moisture through this coating was not substantially different than through typical coatings used on fibers for telecommunications applications.