环氧-玻纤布基板材料的薄型化技术

近年,薄型环氧-破纤布基板材料的开发、应用成为一个热门课题。文章对薄型化CCL的产生背景、三大主要应用领域开拓和对它的性能要求,以及对原材料技术新发展的驱动做一讨论。     

Migration of perfluorinated compounds from paperbag to Tenax® and lyophilised milk at different temperatures

ABSTRACT

Migration tests of perfluoroalkyl substances (PFASs) from a grease-proof paperbag used for packaging of pet food have been carried out. No migration of perfluorocaboxylic acids (PFCAs), from PFBA to PFTeDA, to the simulant Tenax® was found after 10 days at 40°C. However, the increase of temperature in the range 80–160°C gave rise to the migration of the PFCAs. Finally, the migration to real foods such as lyophilised whole and low-fat milk samples at 80 and 120°C was studied. The results indicate that the migration percentages of the PFCASs into food samples are much higher than those obtained into Tenax®.     

Fluorine-based plasmas: Main features and application in micro-and nanotechnology and in surface treatment

Fluorine cold plasmas produced by an electrical discharge in SF₆, CF₄, CHF₃ or C₄F₈ gases, principally, have two main fields of application. The first and historical application is etching of materials for microelectronics and later for micro- and nanotechnology. The second concerns the modification of surface properties, mostly in terms of reflectance and wettability. After an introduction to cold plasmas and plasma–surface interaction principles, the article aims at presenting successively the evolution of fluorine plasma etching processes since the origin with respect to other halogen-based routes in microelectronics, the important and raising application in deep etching and microtechnology, and finally some examples in surface treatment.     

一种基于WLP封装的声表面波滤波器

以41°Y X切型铌酸锂作为基底材料,选择双T型阻抗元结构,采用晶圆级封装（WLP）技术,制作了一款相对带宽5.8%,最小插入损耗为-2.8 dB,体积为1.1 mm×0.9 mm×0.5 mm的小型化WLP封装声表面波滤波器。并研制了专用探卡,对封装后晶圆完成在线测试。测试结果表明,探卡测试结果与装配到实际电路的测试结果进行对比,两者吻合较好,解决了WLP封装声表面波滤波器测试难题。     

“微电子工艺与实践”课程群建设与教改实践

围绕电子信息类专业核心课“微电子工艺”、“微电子器件基础”以及实践课“微电子生产实习”和“微电子器件与工艺实验”等课程教学改革为核心,围绕学生教学主体进行课程群的内容及教学模式调整;运用现代教育MOOC平台和混合式“翻转课堂”教学方法及校企合作实践资源共享等几个环节进行了“微电子工艺与实践”课程群建设,完善教学环节设计,强化实践实习的实效性。     

具有周边硅通孔的晶圆级芯片封装有限元分析

针对外围分布着硅通孔的晶圆级芯片封装结构,利用有限元分析软件ANSYS建立全局模型与次模型,在温度循环试验规范条件下将封装体与硅通孔结构分开进行仿真与探讨。了解模型受到温度载荷所产生的热力学行为。研究发现封装体在经历温度循环试验后所产生的位移呈现圆形对称分布,结构在高温时向外翘曲,在低温时向内弯曲;重布线层在与锡球交界处会产生明显的应力集中。硅通孔结构中铜垫片越接近开孔所受应力越大;硅通孔结构的重布线层部分,应力集中在转角处以及靠近钝化保护层交界处。     

功率器件封装用纳米浆料制备及其烧结性能研究进展

随着SiC、GaN等第三代半导体在大功率器件上的应用,功率器件的工作温度可达到300℃,传统Sn基无铅钎料因为熔点低及钎焊温度高等原因无法满足要求。纳米浆料因其可以实现低温烧结、高温服役的特性吸引了国内外研究者的青睐。从纳米颗粒的合成、纳米浆料的制备、烧结性能以及可靠性等方面综述国内外纳米浆料的研究进展,同时对纳米浆料研究中存在的问题提出一些建议。     

浅析多环特性半导体封装测试系统的性能

半导体封装测试行业已经进入了一个快速发展的时期,面对市场规模的增长和产业竞争的加剧,对半导体封装测试系统的性能进行评估分析,对系统进行合理规划,具有重要的意义.     

Doping of silicon nanocrystals

Over the last decades silicon nanocrystals (Si NCs) were the subject of an intense research activity, due to their optical and electronic properties. Different experimental approaches were developed to synthesize Si NCs embedded in a dielectric matrix as well as freestanding Si NCs with well-controlled structural and morphological characteristics. Actually, as in the case of bulk semiconductors, the fine tuning of their optical and electronic properties is related to the effective capability to control doping, i.e. incorporation impurity atoms within these nanostructures. Even if Si NCs incorporating both p-type and n-type dopants were successfully synthetized, several fundamental issues need to be understood. First of all, from a structural point of view, it is very hard to obtain information about dopant location with respect to Si NCs surface and core. This uncertainty is related either to the intrinsic limitations of the experimental approaches for the synthesis and for the analysis of doped Si NCs, or to the difficulties in the modeling of these nanostructures. Moreover, from a fundamental point of view, it is not clear if impurity incorporation in Si NCs effectively results in the generation of free charge carriers as in the case of bulk silicon. This review presents an overview of the recent progress in the field, focusing on the latest results related to doping of Si NCs. In particular the problem of thermodynamic stability of impurities into Si NCs and the problem of modulation of electrical properties of Si NCs will be systematically addressed.     

Study on the failure temperature of Ti/Pt/Au and Pt5Si2-Ti/Pt/Au metallization systems

The Ti/Pt/Au metallization system has an advantage of resisting KOH or TMAH solution etching. To form a good ohmic contact, the Ti/Pt/Au metallization system must be alloyed at 400℃. However, the process temperatures of typical MEMS packaging technologies, such as anodic bonding, glass solder bonding and eutectic bonding, generally exceed 400℃. It is puzzling if the Ti/Pt/Au system is destroyed during the subsequent packaging process. In the present work, the resistance of doped polysilicon resistors contacted by the Ti/Pt/Au metallization system that have undergone different temperatures and time are measured. The experimental results show that the ohmic contacts will be destroyed if heated to 500℃. But if a 20 nm Pt film is sputtered on heavily doped polysilicon and alloyed at 700℃ before sputtering Ti/Pt/Au films, the Pt₅Si₂-Ti/Pt/Au metallization system has a higher service temperature of 500℃, which exceeds process temperatures of most typical MEMS packaging technologies.