微孔发泡挤出技术制备光缆填充绳

微孔发泡材料是一种新型的改性热塑性聚合物材料,微孔技术的引入,并结合聚合物挤出设备,成就光缆发泡填充绳的诞生,本文主要介绍微孔发泡技术、挤出设备及发泡填充绳成本优势.     

纳米微孔高性能塑料WPX

目前，国内电声行业扬声器音盆的制作材料主要是聚丙烯(PP)及纸浆，极少量的高档产品采用价格昂贵的碳纤、玻纤和蜂巢等复合材料。这几年国外出现了用微发泡PP材料，注塑成型的音盆，低音回应效果十分理想。但这些国家对中国实行技术封锁，不肯提供这方面的设备与技术。鉴于上述情况，上海大都塑胶有限     

高强度耐高温发泡封装材料研究

本简要介绍了用于电子产品的发泡封装材料的发泡机理，配方组成，研制过程，性能测试等，该发泡材料具有良好的耐高低温性能，耐溶剂性、附着力及机械强度等。     

LDS技术在印制电路板行业应用前景分析简

激光直接成型（LDS）技术,指利用激光将数字化的图形照射到高分子材料表面,通过对照射过的区域进行直接金属化,最终在高分子材料表面形成图案的技术。它可以在高分子壳体上直接形成金属化的图案。本文详细探讨了LDS4技术的原理、加工方法、应用方向、在印制电路板中的应用前景以及目前存在的应用缺陷。     

具有多微孔结构的电路基材及其性能

本文介绍了两种新颖的高频应用的具有多微孔结构的电路基材,其中一种采用空心微珠填料,另一种直接利用高分子材料形成微泡沫多孔结构材料;着重综述了这一类新型电子材料的原材料要求制造工艺覆铜板的主要性能及其开发应用前景     

倒锥微孔阵列的激光微加工技术研究进展

激光微加工技术凭借其加工效率高、加工材料广泛、无物理损伤以及操控性强等优点在高精度机械部件的加工上有较好的应用前景,易加工出尺寸微小、数量庞大、高品质的倒锥微孔阵列.首先对激光加工微孔的工作原理和特点进行了介绍,综述了激光在加工微孔阵列、倒锥微孔以及倒锥微孔阵列的研究现状,详细介绍了准分子激光、飞秒激光、纳秒激光在加工...     

利用YAG准分子激光器进行微孔加工的现状

需要微孔加工的应用领域很多,诸如材料方面有金属、高分子材料、硅片、陶瓷等;加工上分机械加工、电火花加工、蚀刻加工、激光加工、喷射加工等,根据材料或加工尺寸、形状而使用不同的加工方法。     

发泡橡胶在扬声器折环中的应用

介绍了近年来发泡材料在扬声器折环中应用的最新进展。阐述了发泡橡胶的原料选择,配方设计和生产工艺,由此获得表面光滑、泡腔精细的发泡橡胶。     

聚丙烯泡沫/铁氧体复合吸波材料研制及应用

介绍了一种新型发泡聚丙烯微孔泡沫吸波材料,并与铁氧体吸波材料进行复合后,在30～1 000MHz的宽频带范围内有优异的反射性能.将复合后的材料应用在3m法电磁兼容暗室,其归一化场地衰减性能仿真计算结果在±4dB以内,其中绝大部分值在±2dB以内,满足高性能电磁兼容电波暗室的设计要求.发泡聚丙烯微孔泡沫吸波材料相对于传统的聚氨酯泡沫吸波材料具有洁净不脱粉、不吸水、耐热性好、硬度强、长期使用不垂头变形等优点,为下一代暗室的建设提供了更多的选择.     

激光微孔加工技术在印刷线路板生产中的应用

在印刷线路板(PCB)加工业中，微孔加工技术一直是制约该丁业发展的主要因素之一，人们对体积小、功能强、性能稳定的产品需求不断推动这项技术的发展。介绍了激光技术在微孔加工方面的应用，阐述了微孔加工的机理、设备、工艺方法及所涉及到的PCB板材料。     

Protective coatings of electronics under harsh thermal shock

Industrial electronics devices commonly encounter harsh environmental conditions during their operational lifetime. To protect the electronics from conditions like humidity and contaminants, protective moulding and coating materials can be used. However, the behaviour of materials in harsh environments and their effect on the reliability of electronics in industrial products has been studied only very little. Moreover, the changes in the parameters of several commonly used materials under various conditions remain largely unknown. In this paper the effect of the protective coating and moulding materials on product level reliability of an electronics device was studied under thermal shock test. In addition, the change in the mechanical properties of the materials under test conditions was studied. The conditions of the test used were relatively harsh with extreme temperatures of −40 °C and +125 °C. The samples used in the study were commercial electronics devices designed for use in harsh conditions. The protective materials studied included silicone based conformal coating, polyurethane based moulding material, and silicone based moulding material. Moreover, a comparison test with no protective materials was conducted. The results showed that conformal coating and polyurethane based moulding material markedly decreased the times to failures of the devices. On the other hand, silicone based moulding seemed to slightly improve the reliability of the devices.     

真空离子镀膜技术在PCB用钻头铣刀上的应用

试验通过真空离子镀膜技术，利用激光轰击靶材形成离子，并使离子在强磁场的驱动下吸附于钻头或锣刀上形成镀层，制备出镀膜钻头及镀膜铣刀，同时分析镀膜钻头与镀膜铣刀在线路板生产制造中的实际应用效果；试验结果表明，采用镀膜钻头，可以明显增加钻孔孔限、减少披锋，节约成本；采用镀膜铣刀进行铣边及成型加工时，有利于减少产品的披锋、毛刺及铣刀断刀，提高生产效率及节约成本。     

我国塑封材料发展形势浅析

本文对集成电路封装用塑封材料的生产、发展进行了浅析，并对集成电路和塑封料的现状、发展趋势、市场前景作了认真的论述，对如何加快塑封料的生产，提升产品品位，缩短和发达国家之间的差距，提出了个人看法。     

Basic thermo-mechanical property estimation of a 3D-crosslinked epoxy/SiO2 interface using molecular modelling

In this work we present a procedure for the construction of 3D networked epoxy moulding compounds and an estimation of basic thermodynamic properties by molecular dynamics simulations. Our investigations present part of general trend to extend failure analysis, reliability assessment and the development of packaging materials from the conventional discrete usage of simulation techniques to a more holistic approach of an interconnected multimethods-procedure, enabling bottom-up simulation of complex microsystems. Within that framework, the task at hand for detailed atomistic molecular modelling is to develop practical methods in order to take materials development as well as materials failure analysis to the nanoscale level. This paper reports a cross linking scheme for the construction of three dimensionally cross linked simulation packages and presents a first property analysis of an industry-oriented moulding compound material. First models and results are presented of model packages of ideal epoxy/silicon-dioxide interfaces.     

New aspects in characterization of adhesion of moulding compounds on different surfaces by using a simple button-shear-test method for lifetime prediction of power devices

The knowledge of moulding compound adhesion on different surfaces inside a semiconductor package is fundamental to ensure high reliability of the devices. The most susceptible interfaces are the boundary surfaces between moulding compound/chip and moulding compound/lead frame. The adhesion properties of these interfaces are influenced by various material and process parameters for chip surface and bond pad conditioning.The knowledge of the zero hour adhesion state and the possible degradations during reliability stress tests like e.g. high temperature storage (HTS) or temperature cycling (TC) is the base to perform a trusty lifetime prediction.This paper shows the principle of button-shear-test method offering the determination of adhesion in a quantitative way. The influence of different moulding compound materials, polyimide layers and bond pad conditioning on moulding compound adhesion on silicon is described by corresponding force–displacement diagrams. Degradation effects of moulding compound adhesion on copper lead frames after performing HTS stress tests is presented and will be discussed.For high accelerated HTS tests the possibility of test time reduction by a factor of 10 compared to automotive qualification standards AEC-Q100/101 is discussed in the paper based on performed experiments (Automotive Electronic Council, 2003, 2005 [1], [2]).     

Warpage in plastic packages: effects of process conditions, geometry and materials

The effects of several important parameters, including processing conditions, package geometry and materials, are specifically studied on the occurrence of warpage and coplanarity for a plastic package. Special emphasis is placed on the evaluation of moulding compound properties and optimal processing conditions that can effectively minimize warpage. It is found that moulding compounds requiring a low moulding temperature and having a low coefficient of thermal expansion (CTE) can significantly reduce warpage. The elastic modulus was found to be inversely proportional to warpage, indicating the modulus should be kept as high as possible. The post-mould curing is essential to reducing warpage as it increases the glass transition temperature, but lowers the thermal shrinkage. A cross-shaped die paddle against a full square paddle, a thick die attach and a large die size are also favorable to reducing warpage.     

Frontal Polymerization Synthesis of Monolithic Macroporous Polymers

A frontal polymerization method is used to produce highly porous polymer monoliths. The method is an approach to polymer synthesis that exploits the heat produced by the reaction itself. This heat triggers polymerization of neighboring monomer molecules, leading to a self‐sustaining hot front, which propagates along the reacting vessel. Dissolved or microencapsulated foaming agents are decomposed only at the fronts, synchronizing the polymerization and the foaming. The ultimate pore structures appear to depend on the polymerization‐front velocity and temperature. The resultant materials are porous, exhibiting tunable pore volume and a multimodal pore size distribution. No organic solvents or high‐pressure equipment are used in the process, and no solvent residues are left in the resulting materials. Specifically, this route allows for the synthesis of large‐scale samples with the additional advantages of high velocity, low energy cost, and the avoidance of multiple process steps. Substitution of hydrophilic acrylamide, N‐isopropylacrylamide, with hydrophobic styrene and methyl methacrylate also leads to porous monolithic materials, suggesting that frontal polymerization represents a powerful and facile method for an exothermic polymerization reaction and the creation of porous polymers.     

Moulding of arrowhead structures

Micron-sized dot-like arrowhead structures were replicated by moulding with an elastomer. In order to address the impact of prepolymer viscosity on stamp filling of the structures and the impact of elasticity on stamp separation of these structures three different PDMS materials were investigated. The moulding results obtained for different geometries of the arrowhead structures were evaluated with respect to typical defects. The results could be well understood in view of the material properties derived from simple characterisation measurements. Sylgard 184 provided the best replication results.     

Copper wire interconnect reliability evaluation using in-situ High Temperature Storage Life (HTSL) tests

This paper describes the use of in-situ High Temperature Storage Life (HTSL) tests based on a four point resistance method to evaluate Cu wire interconnect reliability. Although the same set up was used in the past to monitor Au–Al ball bond degradation, a different approach was needed for this system. Using conventional statistical methods of failure probability distributions and a fixed failure criterion were found to be unsuitable in this case. Besides this, tests usually take very long until a sufficient percentage of the population have failed according to that criterion. A simple physical model was used to electrically quantify ball bond degradation due to the prevailing failure mechanism in a substantially smaller amount of test time. The method enabled the determination of activation energies for a number of moulding compounds and is extremely useful for a fast screening of such materials regarding their suitability for Cu wire.