微导通孔填铜电镀的影响因素研究

由于印制电路板对高密度、高精度、高可靠性及低成本的强烈需求,常规的导通孔敷形镀技术已经不能满足高密度布线的要求,所以提出了微导通孔填铜电镀和微盲孔填铜电镀技术。通过在添加剂方面对影响微导通孔填铜电镀的因素进行分析,运用正交试验的研究方法,得到了添加剂的最优组合和配比,从而实现微导通孔的较好填充。     

关于电镀对印制电路板的重要性

在印制电路板上,铜用来互连基板上的元器件,尽管它是形成印制电路板导电路径板面图形的一种良好的导体材料,但如果长时间的暴露在空气中,也很容易由于氧化而失去光泽,由于遭受腐蚀而失去焊接性。因此,必须使用各种技术来保护铜印制线、导通孔和镀通孔,这些技术包括有机涂漆、氧化膜以及电镀技术。     

提高高厚径比通孔电镀铜均匀性的溶液流动性研究

随着高端印制电路板的层数不断增多,通孔厚径比不断提高,现有技术已经很难满足当前微通孔金属化需求.传统通孔电镀采用的龙门线或垂直连续电镀线,主要采用底部打气或喷流的方式实现镀液的对流,很难促进高厚径比通孔内的物质输运.文章通过设计螺旋桨转动对流仿真模型,研究了镀槽中桨叶形成镀液对流对高厚径比通孔电镀的效果.螺旋桨转动形成...     

集成电路制程可靠性介绍（一）

集成电路制程可靠性是通过特殊设计的电子器件结构来研究集成电路制程工艺相关的可靠性失效模式的物理模型、寿命评估方法,并针对主要失效机理提出对策措施、消除制程开发和生产阶段中的可靠性问题,从而保证集成电路在特定使用年限内的可靠性。表1从可靠性观点的角度,列出了和关键模块相关的失效模式。本文将对这些失效模式的物理图像、模型及重要现象作一简单介绍。     

化学镀铜工艺中内层铜的可靠性

文章作者Crystal Li是罗门-哈斯电子材料亚洲有限公司（香港）电路板技术集团的研究技师。文章主要介绍化学镀铜过程中-目前做通孔或盲孔金属化最常用的制程,可能会影响PcB互联缺陷的一些因素。印制电路板的绝缘材料,其热膨胀系数高于铜材料。因此当焊接使温度升高时,介质的延展大大超过铜的延展。因此,导致增加的应力加到了内层互连的各个表面上。镀铜的通孔和内层铜之间必须要有非常强的结合力,才能使PCB成功地发挥其作用。如果化学镀铜和铜之间或内层化学镀铜和电解铜之间的结合力非常差,热应力就会导致互连缺陷（ICD）发生。     

聚酰亚胺薄膜与PCB技术的结合

高密度组装技术的发展降低了费用,使系统体积更小而且性能更好。具有细线技术的高性能的印制电路板达到了导线宽度小于0.1mm、间距小于0.2mm。印制电路板更高密度的限制因素是机械钻通孔,特别是要装配节距小于0.2mm精细线技术和相应减小导通孔直径以达最小输出面积的现代集成电路(ICs),遇到了困难。为了满足这些要求,研究了用光敏聚酰亚胺作为印制电路板上层的绝缘薄膜的互连系统。为了阐明方法的可行性,建立了一个包括测量接触电阻在内的测试结构的试验模型。     

印制电路板分层起泡原因和分析方法概述

分层起泡是印制电路板（PCB）制造与装配中的一个常见问题,常见于焊接过程、偶尔见于PCB制程中;分层起泡涉及影响因素很多：板材来料、PCB加工、PCB装配加工、返工返修等。PCBA板件分层起泡的失效分析,对PCB制程预防及改善均有一定的参考意义。文章将对分层起泡的失效原因和分析方法进行讨论,以供参考、借鉴。     

多层印制电路板压合参数对板厚均匀性的影响研究

多层印制电路板板厚均匀性影响后制程的背钻深度和阻抗控制,进而影响PCB成品的高速信号传输。文章分析了层压板厚均匀性的影响因素,测试了缓冲材料和压合参数对板厚均匀性的影响。研究结果表明,优化缓冲材料、调整压合参数,均可以改善多层印制电路板板厚均匀性。     

回流焊炉温曲线的管控分析

回流焊温度曲线记录印刷电路板元件焊接过程的温度变化,是元件焊接质量的主要影响因素。针对用测温板获取回流焊温度曲线的影响因素,对测温流程进行潜在失效效应分析,发现利用测温板频繁进行炉温测试具有较高的风险系数。但通过对回焊炉各温区温度的监控与分析,发现回焊炉的制程能力处于优良状态,潜在失效效应的风险系数较低。研究表明,在获取可靠的炉温曲线后,只需要加强炉温监控即可保证焊接质量。     

印制电路板的可靠性设计

本文简要分析了印制电路板可靠性对武备实现整体性能的重要性,以及在对印制电路板质量监督和检验验收过程中存在的误区。立足多年实践,分析了影响印制电路板可靠性的主要因素,提出了针对这些因素重点加强武备印制电路板质量控制工作的重要性和应把握的几个问题。     

Process induced warpage in multitiled alumina substrates for largearea MCM-D processing

Electronics industries are responding to consumer demands in low-cost and high performance products for the 21st century, In order to find a low-cost solution for the future multichip module (MCM) packaging, a multitiling approach through the incorporation of several tiles on a large carrier substrate has been established in this study. The multitiling format provides simultaneous processing of several small (95-mm×135-mm) alumina tiles onto a carrier glass pallet with comparable coefficient of thermal expansion (CTE). The objective of this study is to develop materials and processes for a 300-mm×300-mm format that is scalable up to a 600 mm×600 mm substrate. The fabrication process begins with a carrier substrate on which tiles are attached using a low modulus adhesive. This composite structure is exposed to high temperature thin film process that is required for the MCM-deposited (MCM-D) processing. The tiles are detached from the carrier substrate at an elevated temperature (~4500°C). The warpage of these structures is a critical factor that determines the processability of the thin films in a manufacturing environment. This paper discusses the warpage issues associated with various stages of processing of the proposed large area MCM-D structures     

The QML system for monolithic microcircuits

The qualified manufacturers list (QML) for monolithic microcircuits is described. The approach is commonly known as generic qualification. The QML approach provides for an integrated manufacturing process from device design through final test. It is predicted, on the basis of this philosophy, that quality and reliability can be designed into a product. The implementation of a total-quality-management (TQM) program within the manufacturing unit is key to the success of the QML system. The generic qualification process, the requirements for QML-based products, and the status of the program are designed     

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。     

印制板邮票孔金属化工艺探索

印制板的邮票孔是很普通的加工方法,但金属化邮票孔就不常见了。我在工作中碰到了有这种要求的客户。本着满足客户需求的宗旨,我们将其作为一个专题进行了研究并取得了良好的结果。     

Design for manufacture

The application of the design for manufacture (DFM) approach to the design of printed circuit boards is discussed. A system of design rules is used to ensure that designs meet manufacturing-related needs. The rules capture the requirements of factory processes, so that the needs of manufacturing are considered automatically in the design process. Further, they are flexible, and can be easily adapted to the requirements of different products, factories, and manufacturing processes. Bare-board testing and in-circuit test audits are run to ensure that the board will be testable after fabrication and assembly     

电子标签（RFID）天线的印制技术

文章主要介绍了电子标签(RFID)天线的几种印制工艺。重点讲述了一种新兴的印制工艺——直接印刷法,阐述了这种工艺的工艺流程、特点。直接印刷法具有工艺简单、成本低和环境污染少等优点,将是电子标签(RFID)天线制造工艺的发展主流。     

Determination of Acceleration Factor in Predicting the Field Life of Plated Through Holes From Thermal Stress Data

Accelerated thermal stress tests nowadays have widely been used in qualification and reliability assessment of printed wiring boards (PWBs). Predicting the field life of plated through holes (PTHs) from test data has been a primary goal of this type of testing. Understanding the PTH cycles to failure (CTF) versus temperature relationship and having a good estimate of acceleration factor (AF) not only expedites the data processing process but also helps in optimizing test conditions and minimizing the number of tests, and hence, reducing the test cost. In this paper, three different PTH CTF-temperature models, including an inverse power law (IPL) model, an IPC model, and an enhanced PTH fatigue-life prediction model, are discussed and evaluated in their effectiveness of determining acceleration factors for the purpose of PTH field life prediction under different test conditions. In addition, using the third model, AF influencing factors, including PTH geometric dimensions, PWB glass transition temperatures (Tg), and the temperature dependency of PWB material properties, are also discussed to provide information for accelerated test design in PWB qualification and reliability assessment.      

Quality-reliability chain modeling for system-reliability analysis of complex manufacturing processes

System reliability of a manufacturing process should address effects of both the manufacturing system (MS) component reliability, and the product quality. In a multi-station manufacturing process (MMP), the degradation of MS components at an upstream station can cause the deterioration of the downstream product quality. At the same time, the system component reliability can be affected by the deterioration of the incoming product quality of upstream stations. This kind of quality & reliability interaction characteristics can be observed in many manufacturing processes such as machining, assembly, and stamping. However, there is no available model to describe this complex relationship between product quality, and MS component reliability. This paper, considering the unique complex characteristics of MMP, proposes a new concept of quality & reliability chain (QR-Chain) effect to describe the complex propagation relationship of the interaction between MS component reliability, and product quality across all stations. Based on this, a general QR-chain model for MMP is proposed to integrate the product quality with the MS component reliability information for system reliability analysis. For evaluation of system reliability, both the exact analytic solution, and a simpler upper bound solution are provided. The upper bound is proved to be equal to the exact solution if the product quality does not have self-improvement, which is generally true in many MMP. Therefore, the developed QR-chain model, and its upper bound solution can be applied to many MMP.     

Cognitive-based multi-radio prototype for industrial environment

Today, a large number of cost-saving and energy-efficient applications are enabled by wireless sensor and actuator networks (WSANs). Usually, these solutions have serious connectivity problems in scenarios where other wireless technologies are co-located sharing the frequency spectrum (e.g., industrial shop-floors). To cope with this issue, the concept of multi-radio (MR) has been introduced, which promotes the simultaneous use of multiple radio communication interfaces, leveraging their different characteristics, to improve the overall system performance and reliability. The proposed approach based on cognitive algorithm considers two wireless technologies operating at the 2.4-GHz frequency band, namely Wi-Fi and 6LoWPAN, and provides a concrete implementation of the system using a real test-bed industry scenario. The solution provides a reliable communication infrastructure for manufacturing processes, firstly combining the properties of several physical layer standards and secondly providing the ability to recover from temporary network failures by switching from a communication channel to another one.     

Warpage measurement of large area multitilted silicon substrates atvarious processing conditions

In order to find a low-cost solution for the future MCM-D packaging, a multitiling approach through the incorporation of several tiles on a large carrier substrate was studied. The multitiling format provides simultaneous processing of several small silicon wafers on a carrier glass with a coefficient of thermal expansion (CTE) comparable to that of silicon. The wafers (tiles) are attached to the carrier glass (pallet) using a low modulus adhesive that can be released at an elevated temperature (~450°C). The objective of this study is to develop materials and processes for a 12-in×12-in (300-mm×300-mm) large area substrate that can be scalable up to a 600-mm×600-mm format. The fabrication process begins with a carrier CTE matched Borofloat glass on which silicon wafers are attached using a low modulus adhesive. This composite structure is exposed to high temperature thin-film processes that are required for the MCM-D manufacturing. The warpage of these structures is a critical factor that determines the processability of the thin films in a manufacturing environment. Specimen warpage was obtained using the shadow moire technique. Warpage measurement was performed (i) on as-received glasses, (ii) glasses after polishing, and (iii) pallet assembly after tiling was completed. Although polishing reduced the overall warpage of the as-received pallets, the warpage of the tile and pallet assembly was increased after the adhesive was cured at 150°C. This paper discusses the warpage issues associated with various stages of processing of the proposed large area MCM-D structures