单面电路板通孔再流焊接技术

从理论和实用的角度，阐述了SMD和通孔插装混合安装的高密度组装的电子产品在大规模流水生产中使用再流焊工艺的可行性，并对相关设备作了简单的介绍。     

一种同时适合长短插工艺的新型波峰焊接装置

介绍了一种同时适合长短插工艺的新型波峰焊接装置的基本原理,基本构成以及主要技术特征,列出了使用该装置进行长短插工艺焊接的新方法.     

金丝球焊的工艺质量统计控制

金丝球焊键合工艺作为主要的内部引线互连工艺技术，广泛应用于单片集成电路（IC）及厚薄膜混合集成电路（HIC）中。在批量生产中，其键合质量直接影响产品的可靠性，文章探讨了在批量生产中如何使用质量统计控制方法对金丝球焊键合工艺进行及时有效的调整控制，使其在批量生产中的质量一致性满足产品质量可靠性要求，提高产能和效率。     

Sn-Ag-Cu焊料应用技术

概述了NEC的Sn-Ag-Cu焊料的应用技术现状和引起剥离的解决方法。     

Interfacial reaction of Pb-Sn solder and Sn-Ag solder with electroless Ni deposit during reflow

The interfaces between electroless Ni-P deposit and Pb-Sn solder and Sn-Ag solder were formed by reflowing for different time periods to examine their microstructures and microchemistry. It was found that the Pb-Sn solder interface is more stable than the Sn-Ag solder interface. Sn-Ag solder reacts quickly with the electroless Ni-P deposit and forms nonadherent Ni-Sn intermetallic compounds (IMCs). Pb-Sn solder reacts slowly and forms adherent Ni-Sn IMC. A P-rich Ni layer, revealed as a dark layer under scanning electron microscopy (SEM), is formed on the electroless Ni-P deposit due to the solder reaction. For short reflow times, this P-rich Ni layer consists of only Ni₃P compound, but during prolonged reflow, new crystals of Ni₂P, Ni₅P₄, and NiP₂ are also found to be formed from the amorphous electroless Ni-P layer.     

SMT生产的质量与可靠性

本文介绍了表面贴装产品生产的工艺流程.提出了相应的质量控制程序和技术要求.探讨了发生失效的各种原因,给出了如何在工艺上进行改进以改善焊点的可靠性,提高产品质量的措施.     

Real-time traceability of sorghum origin by soldering iron-based rapid evaporative ionization mass spectrometry and chemometrics

Sorghum is an important grain with a high economic value for liquor production. Tracing the geographical origin of sorghum is vital to guarantee the liquor flavor. Soldering iron-based rapid evaporative ionization mass spectrometry (REIMS) combined with chemometrics was developed for the real-time discrimination of the sorghum's geographical origin. The working conditions of soldering iron-based ionization were optimized, and then the obtained MS profiling data were processed using chemometrics analysis methods, including principal component analysis–linear discriminant analysis and orthogonal projection to latent structures discriminant analysis (OPLS-DA). A recognition model was established, and discriminations of sorghum samples from 10 provinces in China were achieved with a correct rate higher than 90%. On the basis of OPLS-DA, the specific ions of m/z 279.2327, 281.2479, and 283.2639 had relatively strong discrimination power for the geographical origins of sorghum. The developed method was successfully applied in the discrimination of sorghum origins. The results indicated that the soldering iron-based REIMS technique combined with chemometrics is a useful tool for direct, fast, and real-time ionization of poor conductivity samples and acquisition of metabolic profiling data.     

Electro- and thermomigration induced Cu3Sn and Cu6Sn5 formation in SnAg3.0Cu0.5 bumps

Two important trends in the microelectronics business are the development of three dimensional packaging solutions which increase the number electronics components on the same area, and the application of VLSI electronics under harsh environment conditions. Both trends lead to a growing importance of intermetallic compound (IMC) formation in Sn based solder joints. Due to miniaturization a growing part of the solder joint volume is transformed into IMCs and finally the reflow process becomes a transient liquid phase soldering (TLPS) process. For harsh environment applications TLPS enables the transformation of low melting Sn contacts into high melting IMC joints. In both cases a model for the prediction of migration-induced IMC formation is required for the fabrication of IMC joints.For the general prediction of the migration induced IMC formation the related material parameters are needed. Against this background the Cu₃Sn and Cu₆Sn₅ formation was observed during temperature storage tests on Amkor® Package-on-Package packages (12 × 12 mm) with SnAg_3.0Cu_0.5 ball grid arrays. A mathematical model was developed to calculate the average mass flux of Sn and Cu during the stress tests. Based on the mass flux values the activation energies and diffusion constants for Cu and Sn in Cu₃Sn and Cu₆Sn₅ were determined. Afterwards the temperature storage was combined with an AC and a DC current load to investigate thermo- and electromigration-related phenomena. Based on the IMC formation speed during the AC and the DC tests the heat of transport Q^* and the effective charge of the moving ion Z^* were calculated. An interpretation of the material parameters is given in consideration of the high defect density in Cu₃Sn and Cu₆Sn₅.     

插装元件通孔回流焊工艺研究

SMT元器件数量在设计中占绝大多数,但是由于功能的需要不可避免地会有少量THT元件.采用波峰焊接或手工焊接会增加工序而且不能保证质量,然而采用通孔回流焊接工艺则可以较好地解决问题.针对某一款组件设计,导入通孔回流焊工艺,完成所有元器件的组装和焊接,焊点质量满足要求.     

枕头效应的测试与预防

在PCB上组装BGA或CSP时,产生的枕头效应(HIP)令电子制造业很苦恼.枕头效应是由于在再流焊接过程中元件或板子翘曲所引起的,且氧化作用会使枕头效应更为严重.行业急需用于评估可能产生HIP的方法.除了介绍染色法外,还介绍了另外两种简单的方法小滴焊膏法(Tiny Dot Paste)和焊膏上焊球法(Ball Onto Paste).小滴焊膏法重点评估焊膏的抗氧化能力.焊膏上焊球法评估抗氧化性和助焊剂组合能力.这两种方法均是快速、简易和高度仿真的方法,而后者在实际工艺仿真过程中效果更好一些.