模塑阵列封装BGA的翘曲问题

全球BGA封装市场正在不断增大，然而，与QFP封装相比较，BGA封装也存在不足之处。模塑阵列封装BGA(MAP—BGA)的翘曲问题是其主要缺陷，为了减小翘曲，提高BGA封装的特性，应研究模塑料、粘片胶和基板材料，并使这些材料最佳化。     

对细间距球栅阵列封装（FPBGA）焊料裂纹抵抗力问题的探讨

全球BGA封装市场正在增大，这是由于其易于安装到PCB板上。然而，与QFP封装相比较，BGA封装具有一些缺点，如细间距BGA封装的抗焊料裂纹能力较低是其主要缺点。为提高BGA封装的可靠性，应研究各种模塑料、粘片胶和基板材科的最佳组合。     

新一代BGA封装技术

本文主要介绍了 BGA 封装技术的一个分支——新一代 BGA 封装技术:略大于 IC 的载体 BGA(SLICC BGA),缩小型 BGA(m MGA),微型 BGA(μBGA),芯片尺寸封装(CSP),超级焊球阵列封装(Super BGA),混合 BGA 和现场可编程互连器件(FPID)BGA 封装技术。此类技术封装的电路特点是体积更小、成本低、优良的散热性能和电性能。     

BGA封装技术

本文简述了BGA封装产品的特点、结构以及一些BGA产品的封装工艺流程,对BGA封装中芯片和基板两种互连方法——引线键合/倒装焊键合进行了比较以及对几种常规BGA封装的成本/性能的比较,并介绍了BGA产品的可靠性。另外,还对开发我国BGA封装技术提出了建议。     

焊球阵列封装及其返修工艺技术

在简介各种焊球阵列(BGA)封装形式的基础上,归纳出BGA封装的技术优势,包括引脚结构、封装尺寸和封装密度等,并分析了BGA封装的返修工艺技术.分析结果表明,BGA封装进一步缩小了IC的封装尺寸,提高了高密度表面贴装技术水平,因而顺应了LSI和VLSI新品轻薄、短小及功能多样化的发展方向.     

应用Dragon-i技术的Ultra BGA封装基板

初期的BGA封装主要以BT或高Tg的FR-4类的塑性材料为基板，称为PBGA(Plastic BGA)，而使用PBGA封装基板因其具有较大的热阻，因此应用到高速、高功率芯片的封装将会限制芯片性能的正常发挥。1994年Amkor公司为改善PBGA的热耗散特性，开发出Super BGA。Super BGA是第一个专     

MCM—D：一种先进的微电子封装技术

一、MCM－D的特点当今微电子封装领域有两大热门话题，一个是BGA，另一个是MCM。BGA最初是作为一种具有极高封装密度的单片封装形式出现的，它的出现，使得单片电路尺寸减少许多。但对于整机产品而言，系统体积并非由此而减少许多，这就给MCM的发展创造了良好的机遇。而且BGA作     

BGA植球工艺技术

BGA(ball grid array)球栅阵列封装技术是20世纪90年代以后发展起来的一种先进的高性能封装技术,是一种用于多引脚器件与电路的封装技术。BGA最大的特点就是采用焊球作为引脚,这不仅提高了封装密度,也提高了封装性能。而植球工艺作为BGA封装中的关键工艺将会直接影响器件与电路的性能及可靠性。影响BGA植球工艺的主要因素有:植球材料、植球工艺及回流焊工艺。文章通过对BGA植球的基板、焊膏/助焊剂、焊球等材料的详细介绍,详实阐述了植球工艺过程,并对BGA后处理的回流焊工艺进行了详细描述,提供了BGA植球工艺的检测方法,对植球工艺的可靠性进行了探讨。     

新世纪电子器件封装技术展望

扼要分析了电子器件封装技术迅速发展的成因，预测了电子封装新技术的发展方向，深入阐述了引脚布置方式的突破，BGA技术的发展，BGA和倒装芯片结合的优势，CSP产业化的关键，在晶圆片上进行CSP封装的新工艺，以及倒装芯片和CSP封装的综合比校。     

用自动化过程控制技术解决BGA封装难题

主要论述了自动化过程控制技术在BGA封装中的应用、BGA封装技术所面临的困难、合适的BGA封装的选择以及生产技术中存在的各种问题,说明自动化过程控制技术在节省成本、减少返修和提高产品可靠性方面的重要性。     

再流焊温度曲线记录器的研究与应用

目前由于QFP和BGA等器件的大量采用 ,如何准确地测试、调整印制板温度曲线是提高焊接质量的关键。本文重点阐述了WJQ - 3温度记录器的结构与工作原理及应用。     

Critical variables of solder paste stencil printing for micro-BGA and fine-pitch QFP

Stencil printing continues to be the dominant method of solder deposition in high-volume surface-mount assembly. Control of the amount of solder paste deposited is critical in the case of fine-pitch and ultrafine-pitch surface-mount assembly. The process is still not well understood as indicated by the fact that industry reports 52-71% surface-mount technology (SMT) defects are related to the solder paste stencil printing process. The purpose of this paper is to identify the critical variables that influence the volume, area, and height of solder paste deposited. An experiment was conducted to investigate the effects of relevant process parameters on the amount of solder paste deposited for ball grid arrays (BGAs) and quad flat packages (QFPs) of five different pitches ranging from 0.76 mm (30 mil) to 0.3 mm (12 mil). The effects of aperture size, aperture shape, board finish, stencil thickness, solder type, and print speed were examined. The deposited solder paste was measured by an inline fully automatic laser-based three-dimensional (3-D) triangulation solder paste inspection system. Analysis of variance (ANOVA) shows that aperture size and stencil thickness are the two most critical variables. A linear relationship between transfer ratio (defined as the ratio of the deposited paste volume to the stencil aperture volume) and area ratio (defined as the ratio of the area of the aperture opening to the area of the aperture wall) is proposed. The analysis indicates that the selection of a proper stencil thickness is the key to controlling the amount of solder paste deposited, and that the selection of maximum stencil thickness should be based on the area ratio. The experimental results are shown to be consistent with a theoretical model, which are also described.     

Underfilling fine pitch BGAs

Fine pitch BGAs and chip scale packages have been developed as an alternative to direct flip chip attachment for high-density electronics. The larger solder sphere diameter and higher standoff of CSPs and fine pitch BGAs improve thermal cycle reliability while the larger pitch relaxes wiring congestion on the printed wiring board. Fine pitch BGAs and CSPs also allow rework to replace defective devices. Thermal cycle reliability has been shown to meet many consumer application requirements. However, fine pitch BGAs and CSPs have difficulty passing mechanical shock and substrate flexing tests for portable electronics applications. The fine pitch BGA used in the study was a 10 mm package with the die wire bonded. The package substrate was bismaleimide-triazine (BT) and the solder sphere diameter was 0.56 mm. Two types of underfill were examined. The first was a fast flow, snap cure underfill. This material rapidly flows under the package and can be cured in five minutes at 165°C using an in-line convection oven. The second underfill was a thermally reworkable underfill for those applications requiring device removal and replacement. The paper discusses the assembly and rework process. In addition, liquid-to-liquid thermal shock data is presented along with mechanical shock and flexing test results     

再成形（Re—Balled）焊球阵魏封装的焊球强度评估

近年来,许多国家禁止在电子产品中铅的使用,但是一些特定产品拥有豁免权。拥有豁免权的电子产品生产厂商面临含铅元器件供应缺乏的现状,因此生产厂商开始寻求利用焊球再成形技术把焊球阵列封装中的无铅焊球转变为锡铅焊球。焊球再成形技术曾经被用于元器件的回收再利用．但是关于焊球再成形元器件的可靠性信息十分有限。介绍了利用焊球再成形技术使无铅焊球阵列封装转变为锡铅焊球阵列封装。两种焊球去除方法和两种焊球再贴装方法分别用于实现从无铅焊球到锡铅焊球的转变,用以调查再成形工艺对于封装质量的影响。热时效试验以及焊球强度评估用于检测焊球再成形工艺过程。     

Solder Ball Attachment Assessment of Reballed Plastic Ball Grid Array Packages

The ban of lead in consumer-based electronics by many countries has resulted in a dramatic reduction in the availability of electronic components with tin-lead terminations. With the uncertainty associated with lead-free reliability and the issues associated with mixing lead-free solder with tin-lead solder, medical, defense, and aerospace equipment manufacturers are examining and in some cases implementing reprocessing practices to convert lead-free terminations to tin-lead. For area array packages, the practice is referred to as reballing. While reballing has been used for part reclamation, very little information is available on the reliability of reballed parts. This paper presents lead-free ball grid array (BGA) packages subjected to two ball removal and two ball reattachment techniques. Solder attach strength was used as a metric to examine the reballing process. Both the ball shear test and the cold bump pull (CBP) test were used to test solder strength. The impact of isothermal aging was also examined. The solder strength of reballed BGAs remained at the same level when different reballing methods were used and under different aging conditions. The lead-free non-reballed BGAs had higher solder strength and wider strength distribution than reballed tin-lead BGAs. The pull strength increased as the pull speed increased in the CBP test.      

Noise analysis of the quantum flux parametron

An analysis of the limitations imposed by thermal noise on the application of the quantum flux parametrons (QFPs) as current comparators and timing discriminators is presented. At low operational frequencies, a thermal activation approach is used, while at high frequencies a circuit simulation method is required. At frequencies greater than the Josephson junction plasma frequency, an approximate expression for the noise is given. The calculations are in good agreement with the approximations and the experimental results     

The influence of solder composition on the impact strength of lead-free solder ball grid array joints

This study aims to investigate the shear and tensile impact strength of solder ball attachments. Tests were conducted on Ni-doped and non-Ni-doped Sn-0.7wt.% Cu, Sn-37wt.% Pb and Sn-3.0wt.% Ag-0.7wt.% Cu solder ball grid arrays (BGAs) placed on Cu substrates, which were as-reflowed and aged, over a wide range of displacement rates from 10 to 4000 mm/s in shear and from 1 to 400 mm/s in tensile tests. Ni additions to the Sn-0.7wt.% Cu solders has slowed the growth of the interface intermetallic compounds (IMCs) and made the IMC layer morphology smooth. As-reflowed Ni-doped Sn-0.7wt.% Cu BGA joints show superior properties at high speed shear and tensile impacts compared to the non-Ni-doped Sn-0.7wt.% Cu and Sn-3.0wt.% Ag-0.7wt.% Cu BGAs. Sn-3.0wt.% Ag-0.7wt.% Cu BGAs exhibit the least resistance in both shear and tensile tests among the four compositions of solders, which may result from the cracks in the IMC layers introduced during the reflow processes.     

Novel reworkable fluxing underfill for board-level assembly

Underfills are traditionally applied for flip-chip applications. Recently, there has been increasing use of underfill for board-level assembly including ball grid arrays (BGAs) and chip scale packages (CSPs) to enhance reliability in harsh environments and impact resistance to mechanical shocks. The no-flow underfill process eliminates the need for capillary flow and combines fluxing and underfilling into one process step, which simplifies the assembly of underfilled BGAs and CSPs for SMT applications. However, the lack of reworkability decreases the final yield of assembled systems. In this paper, no-flow underfill formulations are developed to provide fluxing capability, reworkability, high impact resistance, and good reliability for the board-level components. The designed underfill materials are characterized with the differential scanning calorimeter (DSC), the thermal mechanical analyzer (TMA), and the dynamic mechanical analyzer (DMA). The potential reworkability of the underfills is evaluated using the die shear test at elevated temperatures. The 3-point bending test and the DMA frequency sweep indicate that the developed materials have high fracture toughness and good damping properties. CSP components are assembled on the board using developed underfill. High interconnect yield is achieved. Reworkability of the underfills is demonstrated. The reliability of the components is evaluated in air-to-air thermal shock (AATS). The developed formulations have potentially high reliability for board-level components.     

球栅阵列器件及其清洗

球栅阵列技术已经激起了电子行业的人们强烈的兴趣。随着人们的目光愈来愈多地关注于BGA器件的组装的时候，对BGA器件进行组装时所产生的清洗和干燥的问题受到了人们广泛的关注，各种各样的BGA器件和焊膏需要采用合适的清洗处理方法。     

BGA器件及其常见的形式

BGA器件不仅能够满足现在已有的其它组件所不能够提供的高性能、大量I/O数量的应用要求,也给如今的有引脚元器件提供了一种可靠的可替换方案。对于在组件体的底部位置安置有大量焊球阵列的BGA器件来说有四种主要的类型。表面阵列配置的组装技术将会成为电子组装业最主要的发展潮流。