酚醛固化环氧基高介电常数覆铜板的研制

天线为通信系统中不可或缺的基本设备。随着电子产品轻、薄、短、小的趋势,电子产品中零件的设计也要朝此趋势发展。当前各界对于天线设计的重点在于小型化、结构简单化及多频或宽带。高介电常数基板可以缩小微波辐射波长,达到天线小型化的目的。文章采用酚醛树脂作为环氧树脂的固化剂,采用高介电常数填料作为功能填料。研制的高介电常数覆铜板具有低的热膨胀系数、低的介电损耗和低的吸水率,可以应用于微带天线。     

二氨基二苯砜固化环氧树脂的促进剂研究

二氨基二苯砜作为一种高耐热低吸湿的环氧树脂固化剂常用于覆铜板领域。研究了不同促进剂对二氨基二苯砜固化环氧树脂反应的影响，表明：2-乙基-4-甲基咪唑和三氟化硼单乙胺络合物，都对二氨基二苯砜固化环氧树脂有一定的促进作用，BF3·MEA可以降低体系的反应温度，提高固化速率；而2-乙基-4-甲基咪唑可以形成更完善的交联结构，具有更高的耐热性。     

国内外覆铜板文献摘录（14）

新型耐热、阻燃环氧树脂及固化剂的合成和性能研究 本文介绍了几种耐热、阻燃环氧树脂及固化剂的合成,利用各种表征手段对其固化物性能进行了研究,讨论了固化物性能同环氧树脂或固化剂结构之间的关系,并对其中部分固化体系的固化反应动力学进行了详细的研究。以1-萘酚和二环戊二烯（DCPD）为主要原料合成了一种新型含萘环和二环戊二烯环结构的环氧树脂NDEP。     

TiO2粒径对PTFE基复合材料介电损耗和吸水率的影响

PTFE/TiO_2复合材料的微观界面结合性直接影响其介电损耗和吸水率性能。本文从增大TiO_2填料粒径的角度出发,以D_(50)为6.258,24.122和34.191μm的TiO_2陶瓷粉分别制备PTFE/TiO_2复合材料样品,测试其在X波段的介电常数、介电损耗和吸水率,结合不同陶瓷粉的特性,分析讨论了TiO_2填料粒径变化对复合材料性能的影响规律。当TiO_2填料粒径增大时,制备的复合材料内部界面比例降低,由界面结合性差导致的高吸水率得到明显的改善。以D_(50)为34.191μm的TiO_2陶瓷粉制备的PTFE基复合材料的相对介电常数为9.97,介电损耗为0.0021,吸水率降低至0.038%。     

FR-4覆铜板生产技术(连载三)

(二)环氧树脂的环氧值与环氧当量环氧树脂是一种热塑性树脂,它必须加入固化剂以后才能固化成为我们需要的产品。产品的性能与环氧树脂的种类,所选固化剂的种类、固化剂的使用量及固化工艺条件密切相关。固化剂的用量通常应用当量定律,按同化剂的胺当量和环氧当量进行等当量反应,通过环氧树脂的环氧值或环氧当量,来计算配方中选用的环氧树脂的用量和固化剂的     

改性环氧树脂导电胶粘剂的研制

以改性环氧树脂为基体,片状银粉为导电填料制备的导电胶,采用内增韧固化剂和第二固化剂复合固化体系实现导电胶的固化。因其有较好的粘接性能和较低的电阻值,兼具室温下初步预固化,加温再固化的特殊性能,可广泛应用于电子元器件的粘接与修复。     

小型化北斗导航圆极化天线研究

结合多种贴片开槽方案,采用正交馈电圆极化激励方式,实现了一款北斗B3(1 268.52±10)MHz频点导航天线的小型化设计。通过电磁仿真软件HFSS对其结构参数进行优化仿真分析,数值结果表明:小型化天线在B3处的顶空增益为3.69 dB,低仰角增益≥-1.5 dB(≤±70°),反射损耗小于-10 dB的带宽为20 MHz,带内轴比≤2 dB。该小型化天线贴片尺寸相比同介电常数基板的同频点未开槽天线缩小72.8%,具有一定的应用前景。     

空心球陶瓷粉填充PTFE基复合基板的制备及性能

为制备低介电常数低损耗微波复合介质基板材料,采用压延工艺,以空心球陶瓷粉为填料制备了聚四氟乙烯(PTFE)基复合基板,系统研究了空心陶瓷粉含量对PTFE基复合基板微观结构和综合性能的影响。结果表明,随空心球陶瓷粉含量的增加,PTFE基复合基板材料断面形貌出现空心球破碎的现象,相对密度逐渐降低,介电常数和介电损耗先降低后升高,吸水率逐渐升高,抗剥离强度呈现下降趋势。当空心球陶瓷粉质量分数为31.3%时,空心结构完整,PTFE基复合基板介质层的密度为1.302 g/cm~3;相对介电常数和介电损耗均最小,分别为1.9659和6.06×10~(-4);吸水率为0.2%,抗剥离强度为2.725 N/mm。     

SiO2含量及粒径对SiO2/聚烯烃复合材料性能的影响

采用溶液法制备了SiO_2填充聚烯烃复合材料,系统研究了SiO_2含量及粒径对SiO_2/聚烯烃复合材料显微结构、力学性能、吸水率、介电性能的影响。结果表明,随着SiO_2含量的增加,复合材料的拉伸强度先增大到一个最大值然后减小,断裂伸长率先稍有增大后逐渐减小,介电常数、介电损耗和吸水率则随SiO_2含量的增加而增加;相同SiO_2填充量时,复合材料拉伸强度、断裂伸长率、介电常数、介电损耗和吸水率均随SiO_2粒径的增大而减小,当SiO_2的粒径为10μm时,复合材料具有最低的介电常数、介电损耗和吸水率。     

应用于天线的高介电常数聚合物基覆铜板

近年来,由于无线通信的快速发展,使无线通信成为生活的必需。天线负责电路与空气中电磁能量的转换,为通信系统中不可或缺的基本设备。随着电子产品轻、薄、短、小的发展趋势,电子产品中元器件的设计也要朝此趋势发展。当前业界对于天线设计的重点在于小型化、结构简单化及多频或宽带。采用陶瓷作为基板制作小型化天线已经是众所周知,然而,陶瓷的不足之处是它易碎,并且有较高的制作成本,因为它必须使用烧结的方法来制备。高介电常数聚合物基覆铜板由于具有易加工、低温成型、低成本和优异的机械性能,已经引起了人们的广泛关注。本文对高介电常数聚合物基覆铜板的设计与制作进行了简要概述。     

氰酸酯型覆铜板催化体系的研究

氰酸酯（CE）具有优异的介电性能、耐热性、低吸湿性和良好的加工性,被广泛应用于低介电高速覆铜板（CCL）。研究了过渡金属离子与第二元催化剂共催化氰酸酯环氧体系的固化反应历程,以及第二元催化剂对板材的介电性能等的影响。结果表明第二元催化剂与过度金属离子有明显的协效催化作用,体系反应温度大幅度降低,同时覆铜板介电性能明显提高。     

氰酸酯／BMI／环氧树脂共混体系在IC封装基板材料中的应用

文章介绍了采用氰酸酯树脂、双马来酰亚胺、环氧树脂共混体系研制一种用于IC封装基板领域的高性能覆铜板。所研制的覆铜板与环氧树脂体系覆铜板相比,具有高Tg、低介电常数、低CTE的性能。     

环氧树脂／氰酸酯／酚醛树脂三元体系在覆铜板中的应用研究

通过红外光谱以及示差扫描量热分析（DSC）等方法分析了环氧树脂／氰酸酯／酚醛树脂三元体系的固化反应过程,并通过该三元体系制作出了具有高耐热性、低介电常数及介质损耗、优异的耐湿热性能及阻燃性、并具有良好加工性能的覆铜板。     

Effects of novel carboxylic acid-based reductants on the wetting characteristics of anisotropic conductive adhesive with low melting point alloy filler

A low viscosity epoxy resin with carboxylic acid-based novel reductants was introduced to improve the process ability and reliability of an anisotropic conductive adhesive (ACA) resin with a low melting point alloy (LMPA) filler system. The curing degree of the ACA resin and the melting of the LMPA filler were investigated using differential scanning calorimetry (DSC) conducted in the dynamic mode in order to control the curing conditions such as the reaction temperature and a melting temperature of solder. The temperature-dependent viscosity characteristics of the ACA resin were investigated using a rheometer. The compatibility between the viscosity of a polymer matrix and a melting temperature of solder was characterized to optimize the processing cycle. Three different types of carboxyl acid-based reductants were added to remove the oxide layer on the surfaces of the filler particles and the conductive pad. Good wetting properties were achieved between the LMPA filler and the Cu pad in the epoxy resin using these carboxylic acid-based reductants.     

A precise numerical prediction of effective dielectric constant forpolymer-ceramic composite based on effective-medium theory

Nanostructure polymer-ceramic composite with high dielectric constant (ϵ_τ~90) has been developed for embedded capacitor application. This polymer-ceramic system consists of lead magnesium niobate-lead titanate (PMN-PT) ceramic particle and modified high-dielectric constant low-viscosity epoxy resin. In order to obtain precise prediction of effective dielectric constant of this composite, an empirical prediction model based on self-consistent theory is proposed. The electrical polarization mechanism and interaction between epoxy resin and ceramic filler has been studied. This model can establish the relevant constitutional parameters of polymer-ceramic composite materials such as particle shape, composition, and connectivity that determine the dielectric properties of the composite. This model is simpler, uses fewer parameters and its prediction compares better with experiment (error <10%). The precision and simplicity of the model can be exploited for predictions of the properties and design of nanostructure ferroelectric polymer-ceramic composites. The effective-medium theory (EMT) has been proved a good tool to predict effective properties of nanocomposites     

Moisture absorption in uncured underfill materials

This paper presents a systematic study on moisture absorption in uncured underfill based on epoxy cured with acid anhydride [methylhexahydrophthalic anhydride (MHHPA)] and epoxy cured with non-acid anhydride curing agent. The influence of absorbed moisture on curing properties, thermomechanical property, and adhesion property of underfill after curing has been investigated. For epoxy cured with non-acid anhydride, the moisture absorption is low, and the absorbed moisture has no significant effect on the properties of cured underfill materials. For epoxy cured with acid anhydride, the moisture absorption before curing can be more than 2.0%, and the absorbed moisture can affect the properties significantly. The absorbed moisture can catalyze the curing reaction between acid anhydride and epoxy. The glass transition temperature of the cured samples is reduced after the underfill absorbs the moisture before curing. The adhesion strength decreases dramatically after the underfill absorbs the moisture before curing.     

Polyhedral Oligosilsesquioxane‐Modified Boron Nitride Nanotube Based Epoxy Nanocomposites: An Ideal Dielectric Material with High Thermal Conductivity

Dielectric polymer composites with high thermal conductivity are very promising for microelectronic packaging and thermal management application in new energy systems such as solar cells and light emitting diodes (LEDs). However, a well‐known paradox is that conventional composites with high thermal conductivity usually suffer from the high dielectric constant and high dielectric loss, while on the other hand, composite materials with excellent dielectric properties usually possess low thermal conductivity. In this work, an ideal dielectric thermally conductive epoxy nanocomposite is successfully fabricated using polyhedral oligosilsesquioxane (POSS) functionalized boron nitride nanotubes (BNNTs) as fillers. The nanocomposites with 30 wt% fraction of POSS modified BNNTs exhibit much lower dielectric constant, dielectric loss tangent, and coefficient of thermal expansion in comparison with the pure epoxy resin. As an example, below 100 Hz, the dielectric loss of the nanocomposites with 20 and 30 wt% BNNTs is reduced by one order of magnitude in comparison with the pure epoxy resin. Moreover, the nanocomposites show a dramatic thermal conductivity enhancement of 1360% in comparison with the pristine epoxy resin at a BNNT loading fraction of 30 wt%. The merits of the designed composites are suggested to originate from the excellent intrinsic properties of embedded BNNTs, effective surface modification by POSS molecules, and carefully developed composite preparation methods.     

Epoxy/BaTiO/sub 3/ composite films and pastes for high dielectric constant and low-tolerance embedded capacitors fabrication in organic substrates

Epoxy/BaTiO/sub 3/ composite embedded capacitor films (ECFs) were newly designed for high dielectric constant and low-tolerance (less than /spl plusmn/5%) embedded capacitor fabrication for organic substrates. In terms of material formulation, ECFs are composed of a specially formulated epoxy resin and latent curing agent, and in terms of a coating process, a comma roll coating method is used for uniform film thickness in large area. The dielectric constant of ECF in high frequency range (0.5/spl sim/3 GHz) is measured using the cavity resonance method. In order to estimate dielectric constant, the reflection coefficient is measured with a network analyzer. The dielectric constant is calculated by observing the frequencies of the resonant cavity modes. Calculated dielectric constants in this frequency range are about 3/4 of the dielectric constants at 1 MHz. This difference is due to the decrease of the dielectric constant of the epoxy matrix. The dielectric relaxation of barium titanate (BaTiO/sub 3/: BT) powder is not observed within measured frequency. An alternative material for embedded capacitor fabrication is epoxy/BaTiO/sub 3/ composite embedded capacitor paste (ECP). It uses similar materials formulation like ECF and a screen printing method for film coating. The screen printing method has the advantage of forming a capacitor partially in the desired part. However, the screen printing makes surface irregularities during mask peel-off. Surface flatness is significantly improved by adding some additives and by applying pressure during curing. As a result, a dielectric layer with improved thickness uniformity is successfully demonstrated. Using epoxy/BaTiO/sub 3/ composite ECP, a dielectric constant of 63 and specific capacitance of 5.1 nF/cm/sup 2/ were achieved.     

Curing kinetics of anisotropic conductive adhesive film

Polymer-based conductive-adhesive materials have become widely used in many electronic packaging interconnect applications, such as chip-on-glass, chip-on-flex, etc. Among all the conductive-adhesive materials, anisotropic conductive adhesive film (ACF) is an attractive interconnect material because of its fine pitch capability. Anisotropic conductive-adhesive film is a thermosetting, epoxy matrix impregnated with a small amount of electrically conductive particles. During component assembly, the epoxy resin is cured to provide mechanical connection, and the conducting medium provides electrical connection in the z direction. The thermal cure process is critical to develop the ultimate electrical and mechanical properties of the ACF. In this paper, the curing reaction of ACF was studied with a differential scanning calorimeter (DSC) under isothermal conditions in the range of 120–180°C. An autocatalyzed kinetic model was used to describe the curing reaction. The rate constant and the reaction orders were determined and used to predict the progress of the curing reaction. A good agreement is found between the proposed kinetic model and the experimental reaction-rate data. The reaction-rate constants were correlated with the isothermal temperature by the Arrhenius equation. The glass-transition temperature also has been studied as a function of cure degree and moisture absorption.     

聚酰亚胺覆铜板

以4,4-二苯甲烷双马来酰亚胺、二氨基二苯甲烷、环氧树脂为主要原料合成性能优良的改性聚酰亚胺树脂体 系;以此为基体树脂,以玻璃纤维布为增强材料制作覆铜板;该板材具有玻璃化温度高、介电常数低等优异的综合性能,可 用于制作高温、高频印制线路板。