铜基引线框架电镀铜、银的显微结构及可焊性

在自动电镀线上对铜基引线框架表面分别镀铜和镀银。通过扫描电镜(SEM)和能谱(EDS)分析及钎焊试验对比了Cu镀层和Ag镀层的微观形貌、元素分布和焊接性。结果表明,银在引线框架基岛表面具有更好的沉积效果,所得Ag镀层平整光滑,结构致密。焊点在Ag镀层表面覆盖直径大于Cu镀层,表现出更好的焊接性。     

基体表面性质对引线框架上无铅镀锡层的影响

研究了铜基引线框架基体表面性质对镀锡层的影响.扫描电镜(SEM)和X射线衍射(XRD)分析结果表明:镀层外观由其结晶结构决定.采用X射线光电子能谱(XPS)研究了铜基引线框架表面性质的影响.结果表明:引线框架表面铜的氧化状态对于最终所得镀锡层的性质有很大影响,当引线框架表面存在大量的CuO时,得到的镀锡层易于出现发黑等...     

引线框架铜带显微组织对电镀镍层性能的影响

采用具有不同显微组织的引线框架用C19400铜合金为基材进行电镀Ni,采用扫描电子显微镜(SEM)、光学显微镜(OM)、粗糙度测量仪等分析了铜合金的显微组织对Ni镀层形貌、厚度和表面粗糙度的影响。结果表明:镀层厚度随铜材中变形组织的增加而减小,退火态(O态)基材表面Ni镀层厚度达到了6.11μm,剧烈变形(SH态)基材表面Ni镀层厚度仅为3.73μm。Ni镀层会“复制”铜基材的表面形貌,变形量较大的基材电镀Ni后粗糙度的增幅小于变形量较小的基材。电镀时应结合基体材料的显微组织来调整工艺参数,以获得性能较优的镀层。     

表面处理对铜铝双金属界面结合强度的改善研究

铜和铝作为两种具有广泛应用和优异性能的金属,其组合产生的双金属复合材料具有许多独特的优点。铜具有良好的导电性、导热性、易焊接性、低接触电阻、易电镀性和美观的外观,而铝则以其廉价、质轻、优异的散热性能和经济性而闻名。通过将铜和铝合成为双金属复合材料,可以实现两种金属的优点的整合,为各种工业应用提供了极具吸引力的材料选择。本研究旨在探讨表面处理技术对铜铝双金属界面结合强度的影响,并尝试找到能够有效改善界面结合强度的表面处理方法。     

硅氢基与乙烯基比例对大功率LED封装用有机硅树脂固化行为的影响

选用端乙烯基苯基硅油为基础树脂,含氢苯基硅油为固化剂,铂络合物为催化剂制备了发光二极管(LED)封装用有机硅树脂。用非等温差示扫描量热分析法研究了硅氢基与乙烯基比例对有机硅树脂的固化行为的影响。结果表明,硅氢基与乙烯基比例为1.6时,固化温度最低,即反应条件最为温和;确定固化工艺为真空脱泡后前段固化温度为80 ℃/1 h,而后95 ℃/2 h。     

自动电镀线拉片速率对引线框架镀层微观结构和钎焊性的影响

在自动电镀线上对铜基引线框架表面电镀铜镀层,并以Sn–Pb合金进行钎焊试验.采用扫描电镜(SEM)和能谱仪(EDS)考察了镀层和焊接截面的显微结构及元素分布,研究了拉片速率对镀层微观形貌、Sn–Pb合金的润湿行为以及焊接截面元素分布的影响.结果表明,拉片速率越大,铜的沉积时间越短,电镀层的致密性越差,对Sn–Pb合金的钎焊性也越差.以8 m/min拉片速率形成的铜镀层表面平整、致密,钎焊后的Cu/Sn界面连接完整,具有较好的微观结构和焊料润湿效果.     

电解去溢料工序参数对IC封装体第二焊线区分层的影响

IC封装体的内部分层是封装过程中常见的质量问题.讨论了引线框架电镀工艺对IC封装体第二焊线区分层的影响,并确定了电镀工艺的电解去溢料工序是使其分层的主要因素.通过实验分析并验证了电解去溢料工序的电压、电解电极的极性、电解液的类型及其浓度对第二焊线区分层的影响.通过对不同封装体第二焊线区分层程度的比较,认识到电解去溢料对一些大载荷小封装的IC封装体是不适用的,极易引起第二焊线区分层,从而使IC产品存在失效的风险.实验评估的结果为今后的封装体设计及生产工艺提供了可借鉴的经验.     

处理条件对丙烯酸树脂交换容量和强度的影响

研究了温度、酸碱处理对弱碱性丙烯酸树脂交换容量和强度的影响。50℃热水浸泡和1mol/L酸碱周期处理使得一类弱碱性丙烯酸树脂交换容量较快下降,下降约8%后,有明显转折点,下降平缓;使得另一类丙烯酸树脂交换容量逐步下降,无明显转折点,但总体下降趋势越来越小。50℃热水浸泡对丙烯酸树脂强度影响很小,下降约2%后,下降平缓;1mol/L酸碱周期处理使得丙烯酸树脂强度越来越小。     

整平剂及电流密度对电子封装用铜微凸点电镀的影响

研究了宏观整平剂、微观整平剂及电流密度对铜微凸点表面平整性的影响,探讨了2种整平剂和电流密度对铜微凸点表面的作用机制.镀液组成和工艺参数为:CuSO475 g/L,H2SO4100 g/L,Cl-50 mg/L,整平剂H和W0～10 mg/L,(25±2)℃,60 r/min,1～8A/dm2,35 min.结果表明,宏观整平剂可促进铜的沉积,微观整平剂则可抑制铜的沉积,二者相互配合可改变电镀过程中镀孔的电力线分布,使电流密度分布均匀.在一定范围内提高电流密度可加快铜微凸点的生长.在6 A/dm2下,2种整平剂的质量浓度均为5 mg/L时,可制得结晶细腻、表面平整的铜微凸点.     

树脂对芳纶无纬布防弹防刺性能的影响

采用树脂与芳纶无纬布模压的方法,制备了一种具备防弹防刺功能的复合材料,讨论了模压温度、时间、压力等因素对其性能的影响。实验结果表明,以树脂和芳纶无纬布为原料制备的防弹防刺复合材料,其工艺优化条件为：模压时间15～30min,温度125℃,压力2～4MPa。在此条件下,制得的复合材料的防弹防刺综合性能最佳。     

镍框架与环氧树脂之间的粘接力改善研究

利用模封机对不同镀层的框架材料和环氧树脂进行注塑,然后利用粘接力测试仪对框架和环氧树脂之前的粘接力进行了分析,发现镍、金和镍钯银金的镀层材料中,镍镀层的粘接力最小,通过改性的方式可以增大镍层与环氧树脂之间的粘接力,将改性后的镍框架组装成产品后,发现可靠性前后产品的分层失效问题可以得到解决.     

Cure shrinkage analysis of epoxy molding compound

EGA (ball grid array), one of the structures Used for semiconductor packages, involves a laminated structure. BGA inevitably involves significant warpage, owing to differences in shrinkage among constituent materials. The extent of warpage is governed by total shrinkage (= cure shrinkage + thermal shrinkage) of the epoxy molding compound that encapsulates the IC chip. In particular, the cure shrinkage exerts great influence on warpage. Cure shrinkage has been understood as the decrease in free volume at the time of curing. However, the cure shrinkage rate cannot be sufficiently explained by the free volume of the cured epoxy resin. We have developed an evaluation method based on the epoxy group reaction ratio, and have eventually confirmed that cure shrinkage depends on the reaction ratio of the epoxy group after curing, and on epoxy group density.     

联苯型环氧液晶改性环氧塑封材料的性能研究

合成了一种端环氧基的联苯型液晶(LCEP),采用红外光谱(FT-IR)、示差扫描量热法(DSC)和偏光显微镜(POM)对其结构和热性能进行了分析,并以LCEP、环氧树脂、无机粉体(Al2O3和AlN)制备了环氧塑封料,通过对其力学性能、导热系数、线膨胀系数、电性能及热稳定性的测试研究了LCEP及无机粉体的加入对塑封料性能的影响。结果表明:加入LCEP后,塑封材料的冲击性能、弯曲性能均有所提高。同时,塑封料的导热系数、介电常数、热分解温度随着Al2O3、AlN含量的增加而增大,LCEP对于提高材料的导热性和热稳定性也有一定贡献。而线膨胀系数、介电损耗随着Al2O3和AlN含量的增加而降低,加入LCEP后塑封料的线膨胀系数略有降低。     

环氧电工塑料的固化反应动力学研究

以双马来酰亚胺(BMI)/二氨基二苯砜(DDS)为组合固化剂,采用非等温示差扫描量热法(DSC)研究了邻甲酚醛环氧树脂(ECN)/DDS/BMI三元体系的固化反应动力学,用Kissinger法和Crane公式进行DSC数据处理,获得了固化反应动力学参数,并建立了固化动力学模型,同时结合红外光谱分析探讨了该体系的反应机理。结果表明,ECN/DDS/BMI体系固化反应级数n=0.93;表观活化能Ea=58.2 kJ/mol,与ECN/DDS体系相差很小,BMI的加入对体系的固化工艺影响不大,ECN/DDS/BMI体系的固化动力学模型与ECN/DDS体系相似。     

环氧片状模塑料用微胶囊固化剂的制备

以2-乙基-4-甲基咪唑(2E4MI)为芯材、聚乙二醇(PEG-6000)为壁材,采用熔融喷雾法制备了一种环氧片状模塑料用微胶囊固化剂。对微胶囊进行了表征,对环氧树脂的固化行为进行了研究。研究表明,该胶囊固化剂中囊芯材料2E4MI的质量分数约为l3.7%。ESMC的最佳固化工艺确定为:101℃/10min+111℃/10min+150℃/10min+180℃/10min。微胶囊化固化剂中的PEG-6000壁膜在常温下可以阻止环氧树脂的固化,使ESMC树脂糊体系具有更好的室温贮存稳定性。固化剂的微胶囊化不会引起固化机理的变化。环氧树脂的固化度α可达0.93。     

High thermal conductive epoxy molding compound with thermal conductive pathway

The epoxy molding compound (EMC) with thermal conductive pathways was developed by structure designing. Three kinds of EMCs with different thermal conductivities were used in this investigation, specifically epoxy filled with Si₃N₄, filled with hybrid Si₃N₄/SiO₂, and filled with SiO₂. Improved thermal conductivity was achieved by constructing thermal conductive pathways using high thermal conductivity EMC (Si₃N₄) in low thermal conductivity EMC (SiO₂). The morphology and microstructure of the top of EMC indicate that continuous network is formed by the filler which anticipates heat conductivity. The highest thermal conductivity of the EMC was 2.5 W/m K, reached when the volume fraction of EMC (Si₃N₄) is 80% (to compare with hybrid Si₃N₄/SiO₂ filled‐EMC, the content of total fillers in the EMC was kept at 60 vol %). For a given volume fraction of EMC (Si₃N₄) in the EMC system, thermal conductivity values increase according to the order EMC (Si₃N₄) particles filled‐EMC, hybrid Si₃N₄/SiO₂ filled‐EMC, and EMC(SiO₂) particles filled‐EMC. The coefficient of thermal expansion (CTE) decreases with increasing Si₃N₄ content in the whole filler. The values of CTE ranged between 23 × 10^?6 and 30 × 10^?6 K^?1. The investigated EMC samples have a flexural strength of about 36–39 MPa. The dielectric constant increases with Si₃N₄ content but generally remains at a low level (<6, at 1 MHz). The average electrical volume resistivity of the EMC samples are higher than 1.4 × 10¹⁰ Ω m, the average electrical surface resistivity of the EMC samples are higher than 6.7 × 10¹⁴ Ω. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Thermally conductive EMC (epoxy molding compound) for microelectronic encapsulation

Owing to the trend of faster and denser circuit design, the dielectric properties of packaging materials for semi-conductors will have greater influence on performance and reliability. Also, as chips become more densely packaged, thermal dissipation becomes a critical reliability issue. Consequently, four important properties for manufacturing semi-conductor packaging are: low values of dielectric constants, high values of thermal conductivity, relatively low values of thermal expansion coefficients, and low cost. Thus, in this study, AlN (Aluminum Nitride) was selected as the filler for an epoxy matrix to achieve increased performance of an EMC. As a result, the thermal conductivity of an EMC filled with 70 vol% of AlN increased as much as 7–8 times compared with the EMC filled with a crystalline silica (vol. 70%). When more than 60 vol% of AlN was added to the EMC, the dielectric constants and thermal expansion coefficient decreased rapidly.     

Effects of curing accelerators on physical properties of epoxy molding compound (EMC)

The effects of various curing accelerators on the physical properties of epoxy molding compounds (EMCs) were investigated. Such properties as elasticities in rubbery and glassy regions, glass transition temperature, thermal expansion coefficient, and water absorption at 60°C of neat epoxy resins using various curing accelerators were found to be directly reflected in the properties of the EMCs that were prepared by using each resin system. However, volume resistivity and saturated water absorption at 120°C were not reflected. This was attributed to differences in the catalytic reactivity of accelerators causing different melt viscosity for the EMC, which resulted in different densities (packing degrees) and affected physical properties of molded EMC. On the other hand, it was found that the density of molded EMC was also affected by the molding conditions. To improve the physical properties of the molded EMC, in addition to proper selection of accelerators, it was very important to set the melt viscosity of the EMC as high as possible within the moldable range and to select suitable molding conditions.     

Physical properties of epoxy molding compound for semiconductor encapsulation according to the coupling treatment process change of silica

The change of physical properties of an epoxy-molding compound (EMC) for semiconductor encapsulation according to the coupling treatment process change was investigated. Three different coupling treatment processes were applied in this study: the pretreatment method (PM), the internal pretreatment method (IPM), and the integral addition method (IAM). Especially, we suggested a simple and economic process, the IPM process, in which the drying and powdering process is excluded compared with the PM process. The optimum content range of the coupling agent is 1.0–2.0 wt % based on the weight of the filler, which is about a 1.3–2.5 coating layer. The flexural strength and internal stress of EMC made by the IPM process is almost equivalent to that made by the PM. We applied the model of complex layers of a silane coupling agent at the filler/matrix interface in interpretating the mechanical and thermal properties of EMC and obtaining the relationships between physical properties and the coupling process. It can be concluded that the IPM process is an effective and economic process to be able to obtain a good reliable EMC with strong mechanical strength and low internal stress. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 1975–1982, 1997     

Synthesis and properties of a low hygrothermal stress epoxy molding compound for electronic encapsulation

A vinyl siloxane‐modified cresol novolac epoxy (CNE)/cresol novolac hardener (CNH) molding compound with both siloxane and epoxy components capable of further crosslinking is synthesized. Through careful adjustment of TPP dosage, the Tg of CNE/CNH resins can be effectively controlled. The VS‐modified CNE/CNH compound possesses a lower Young's modulus, a lower linear coefficient of thermal expansion (LCTE), and a higher break strain than those of its unmodified counterpart. The combination of lower mechanical moduli and lower LCTE results in a 33% reduction in thermal stress caused by thermal mismatch. In addition to thermal mismatch, chemical shrinkage in a molding process is also an important factor that affects the interfacial strain between a compound and a substrate. The incorporation of vinyl siloxane (VS) incurs a 25% reduction in the equilibrium moisture uptake and a 16% reduction in the coefficient of diffusion for the VS‐modified compound. This modified compound can help alleviate the popcorning problems in IC packages resulting from hygrothermal stresses.