高可靠性18层刚挠结合印制板制作技术研究

文章通过介绍一款用于航空方面的18层高可靠性刚挠结合印制板在压合、盲槽制作、半固化片开窗、覆盖膜压合等技术点的突破,提出一套适用于此类高层高阶刚挠结合印制板的制作技术。     

聚四氟乙烯多层天线板制作工艺开发

目前天线板主要采用于双面PCB制作,而随着通讯技术的发展,有源、多层天线PCB产品的需求日益增长,PTFE多层板的开发正是在这样背景下应运而生。文章基于对PTFE多层板的板材性能、PCB制作难点、关键品质控制以及可靠性等方面进行研究,解决了PTFE材料压合、机加工、通孔沉铜电镀、阻焊制作等难点,成功开发了厚度2.5 mm、最小通孔孔径0.5 mm、孔粗≤30 m、内外层线路蚀刻因子≥3.0、PIM≤-107dbm的6层纯PTFE天线板,并具备批量生产能力。     

环氧树脂类阻焊膜制作技术及其在印制板上的应用

本文对印制板所用环氧树脂类阻焊剂的制作技术进行了简单介绍，对提高阻焊膜印制板的粘接性能之要点进行了较为详细的论述。     

多层印制板生产中的非金属材料保护技术

对多层印制板生产中的阻焊膜保护技术进行了详细阐述。对阻焊膜制作的工艺过程、工序过程的质量控制、产品质量问题的产生原因及所采取的相应对策进行了简要介绍。     

微波材料选用及微波印制电路制造技木

4．3．7一种聚四氟乙烯微波印制板制造技术 1．前言 目前,设计、加工制作的微波印制板,采用的主要是进口的微波印制板和国产泰兴板。鉴于该类聚四氟乙烯高频印制板在孔金属化处理、阻焊膜制作及热风整平加工等方面存在一定程度的缺陷,     

特殊凹腔印制板压合阻胶方案研究

对于一种槽底有导通孔、槽壁非金属化设计的特殊凹腔印制板,采用带有导通孔的母板与带有非金属化槽的子板压合、烧结制作工艺,其关键技术是阻止半固化片流胶污染槽底金属化区域。通过测试半固化片铣空区补偿和PTFE垫片两种阻胶方案,初步探索出特殊凹腔印制板的压合工艺,为此类样板的制作提供了可行的技术方案。     

阻焊外观缺陷统计与控制

阻焊剂作为印制板永久性绝缘保护层,阻焊层上的异物、不均匀甚至细小脱落、破损都将直接影响到印制板的成品外观,甚至危害到印制板的电气性能。为了减少这种现象的发生,我们系统地统计了网印晒阻焊、后固化、热风整平、印字符、铣外形以及清洗各工序对阻焊的损伤,从重点入手,制定相应的保护措施,减少阻焊缺陷。     

一种新的互连技术——B~2it法

本文介绍了一种新的印制板互连技术。该技术是通过导电凸块实现层间互连。与传统的PTH法相比,不要钻孔、化学沉铜和电镀铜等操作。简化了制作工艺。其连接可靠性达到或超过PTH法。适合于高组装密度及MCM—L的制作。     

大尺寸背板工程设计和压合制作关键技术探讨

随着背板厚度和尺寸的不断增加,压合的制作难度也随之增加,文章主要从材料选择、工程设计、排板方法、压合程序等几个方面进行介绍,通过优化相关资料和工艺方法,来解决压合过程中易出现的层偏、缺胶、空洞等一系列的品质问题,最终降低了大背板压合工序的报废率,提高了大背板的制作能力。     

PCB专用阻焊剂及发展趋势

现代化的装配工艺采用机械化和自动化来实现,为了提高质量及生产效率,对于印制板的焊接多选用波峰焊或浸焊工艺,这就要求在印制板上有一层永久性的保护层,防止焊料侵入非规定区域。用作阻焊层的涂料称为阻焊剂,其主要分为干膜型阻焊剂、热固型、UV 光固型阻焊剂及感光显影型液体阻焊     

Design of Experiments for Board-Level Solder Joint Reliability of PBGA Package Under Various Manufacturing and Multiple Environmental Loading Conditions

A design of experiments was conducted to determine the reliability of plastic ball grid array packages under various manufacturing and multiple environmental loading conditions. Parameters included conformal coating methods, underfill, solder mask defined, and non-solder mask defined pads. Board-level temperature cycling, vibration, and combined temperature cycling and vibration testing were performed to quantify the reliability and identify preferred design parameters. Through the main effects and interaction analysis, test results show underfill is the key parameter related to the solder joint reliability improvement. Conformal coat method and printed circuit board pad design are not main effects on solder joint reliability. No interactive relationship exists among these three factors under temperature cycling loading, but some interactive relationship between printed circuit board pad type and the conformal coating method exists under vibration and combined loading conditions.     

Surface property of passivation layer on integrated circuit chip and solder mask layer on printed circuit board

Adhesion of underfill to passivation layer on integrated circuit chip and solder mask layer on printed circuit board is critical to the reliability of an underfilled flip chip package. In this study, the surface properties of solder mask and four passivation materials: benzocyclobutene (BCB), polyimide (PI), silicon dioxide (SiO/sub 2/), and silicon nitride (SiN) were investigated. A combination of both wet and dry cleaning processes was very effective to remove contaminants from the surface. The element oxygen, introduced during O/sub 2/ plasma treatment or UV/O/sub 3/ treatment, led to the increase of the base component of surface tension. X-ray photoelectron spectroscopy (XPS) experiments confirmed the increase of oxygen concentration at the surface after UV/O/sub 3/ treatment. Wetting of underfill on passivation and solder mask was slightly improved at higher temperatures. Although UV/O/sub 3/ cleaning and O/sub 2/ plasma treatment significantly improved the wetting of underfill on passivation materials, they did not improve adhesion strength of epoxy underfill to passivation. Therefore, the wetting was not the controlling factor in adhesion of the system studied.     

Experimental and statistical analyses of surface-mount technologyPLCC solder-joint reliability

The mechanical integrity of surface-mount technology (SMT) plastic leaded chip carrier (PLCC) solder joints has been studied by a four-point mechanical flexure fatigue test. The effects of printed circuit board (PCB) pad surface composition and testing temperature on solder-joint reliability are emphasized. Three sets of PCBs have been tested, one with Cu-Ni-Sn pad surface metallurgy, one with Cu-Ni-Au, and one with SMOBC/SSC (solder mask over bare copper selective solder coating). The solder composition was the 63 wt.%Sn/37 wt.%Pb eutectic. A two-parameter Weibull distribution was used for the lifetime model for these three products. The uniformity, quality, reliability, and a comparison of these products are discussed. The joints formed on Cu-Ni-Au and SMOBC boards were appreciably more reliable than those formed on the Cu-Ni-Sn board     

一种超厚铜板制作工艺探讨

通常铜厚≥350mm（10 oz）以上电路板称为超厚铜板,其主要应用于大电流大功率电源、清洁能源太阳能等产品。随着这类产品需求量的迅速增长,未来超厚铜板必然会成为PCB发展的另一趋势之一。超厚铜板由于铜厚较厚,制作时内层无铜区填胶、钻孔、蚀刻等工序都存在一定的难度。文章通过制开发28 oz的超厚铜板,对选用的材料及制作工艺等方面进行优化,解决了这类板制作过程中蚀刻、压合、钻孔等工序的制作难点,为业内同行制作此类超厚铜板提供参考。     

多层电路板快速制作工艺的研究

从多层电路板加工工艺的角度,介绍多层板在设计需要考虑的因素以及布局与厚度、孔径与焊盘、线宽与间距和敷铜区的设计原则和计算关系,阐述了多层板的重点制作工艺流程,并详细介绍了孔金属化和去除钻污的处理流程,具体给出在实验室快速制作多层板工艺的方法.     

改善阻焊溢油方法研究

从分析“阻焊塞孔”在制造过程中产生“阻焊溢油”不良原因,及不同GERBER图形设计条件下使用不同的CAM工具入手,在采用专用的“塞孔油墨”的基础上,探讨通过优化“阻焊照片”、“塞孔铝片”为主,“树脂塞孔”工艺替代和“分段固化”为辅,达到预防和降低“阻焊溢油”不良的目的,从而提高PCB产品可靠性。     

Major factors to the solder joint strength of ENIG layer in FC BGA package

Since electroless nickel and immersion gold (ENIG) process was implemented as the surface finish of printed circuit board (PCB) substrate, there have been lots of reports on the brittle fracture between the Ni–P (phosphorous) layer and solder which results in the poor solder joint strength performance. Galvanic corrosion during immersion Au plating process and P-content in Ni–P layer were considered as major factors in the solder joint strength of ENIG layer in this investigation. The attempt to reduce the galvanic corrosion attack in Ni–P layer was made by changing immersion Au plating process to partial electroless Au plating process. Reducing the galvanic corrosion attack was proved to be effective to improve the solder joint strength of ENIG layer. Evaluation of the solder joint performances in variation with the thickness of the Ni layer leads to the conclusion that the thicker Ni layer has the better solder joint strength performances. The result also showed that higher P-content in Ni layer is more favorable to the solder joint strength.     

Improved reliability in small multichip ball grid arrays

The subject of this paper is a 14×22 mm ball grid array (BGA) integrated circuit assembly containing two or three chips. Three failure modes came to light in the reliability testing of this BGA package: delamination of solder resist from the top copper layer occurred in moisture resistance testing; cracking of the top layer solder resist and consequent cracking of the top copper layer occurred in temperature cycling; and cracking of the bottom layer solder resist which propagated into the bottom copper layer occurred in thermal shock. The failure analysis techniques used to disclose these failures are presented. Finite element analysis of thermomechanical stress within the multichip structure was carried out. The purpose was to find the root cause of one of the failure modes and to explore possible means of overcoming the stress damage. The characteristics of the original and modified substrate layout designs are detailed. The improved performance in reliability testing is compared with the original. All failure modes were eliminated in the final design, and the product was qualified to greatly improved reliability standards.     

Mechanical deflection system (MDS) test and methodology for PBGAsolder joint reliability

A mechanical deflection system (MDS) was developed for highly accelerated tests to evaluate the solder joint fatigue performance in printed circuit board assemblies. The MDS test system can be used for design verification and qualification tests for solder joint reliability. Cyclic twisting deformation is imposed on an assembled printed circuit board (PCB) at isothermal conditions. The MDS test technique makes a significant contribution to reducing solder joint reliability testing cycle time. Fatigue performance of the PBGA solder joints subjected to the MDS test was investigated by three-dimensional finite element modeling. The solder joint fatigue lives were computed for several different MDS test conditions