信息与通信PCBA介绍.pptx

,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,2019/12/13,#,Conception of PCBA,什么,是,PCBA,PCBA,是英文,Printed Circuit Board+Assembly,的简称，也就是说,PCB,空板经过,SMT,等工艺上件，再经过,DIP,插件的整个制程，简称,PCBA,PCB Introduction PCB,介绍,PCB,（,Printed Circuit Board,）,中文名称为,印制电路板,，又称印刷电路板、印刷线路板，是重要的电子部件，是电子元器件的支撑体，是电子元器件电气连接的提供者。由于它是采用电子印刷术制作的，故被称为“印刷”电路板,PCB,板的分类,根据材质分：,a.,有机材质,酚醛树脂、玻璃纤维,/,环氧树脂、,Polyimide,、,BT/Epoxy,等皆属之。,b.,无机材质,铝、,Copper-invar-copper,、,ceramic,等皆属之。主要取其散热功能,根据电路层数分类：,分为,单面板,SSB,(,见图,1,）,、双面板,DSB,（,见图,2,）,和多层板,MLB,（,见图,3,）,。常见的多层板一般为,4,层板或,6,层板，复杂的多层板可达几十层,根据软硬进行分类：,分为,刚性电路板,RPC,和柔性电路板,FPC,(,见图,4),、软硬结合板,(,见图,5,),依用途分：,通信,/,耗用性电子,/,军用,/,计算机,/,半导体,/,电测板,（,见图,6,）,BGA,图,2,图,5,图,3,图,4,图,1.,图,5,图,6,单面板,（,Single-Sided Boards,）,在最基本的,PCB,上，零件集中在其中一面，导线则集中在另一面上。因为导线只出现在其中一面，所以这种,PCB,叫作单面板（,Single-sided,）。因为单面板在设计线路上有许多严格的限制（因为只有一面，布线间不能交叉而必须绕独自的路径），所以只有早期的电路才使用这类的板子,双面板,（,Double-Sided Boards,）,这种电路板的两面都有布线，不过要用上两面的导线，必须要在两面间有适当的电路连接才行。这种电路间的“桥梁”叫做导孔（,via,）。导孔是在,PCB,上，充满或涂上金属的小洞，它可以与两面的导线相连接。因为双面板的面积比单面板大了一倍，而且因为布线可以互相交错（可以绕到另一面），它更适合用在比单面板更复杂的电路上,多层板,（,Multi-Layer Boards,）,为了增加可以布线的面积，多层板用上了更多单或双面的布线板。用一块双面作内层、二块单面作外层或二块双面作内层、二块单面作外层的印刷线路板，通过定位系统及绝缘粘结材料交替在一起且导电图形按设计要求进行互连的印刷线路板就成为四层、六层印刷电路板了，也称为多层印刷线路板。板子的层数就代表了有几层独立的布线层，通常层数都是偶数，并且包含最外侧的两层。大部分的主机板都是,4,到,8,层的结构，不过技术上理论可以做到近,100,层的,PCB,板。,PCB,板制作流程,收到客户资料,-Gerber,，制作规格单,资料处理,-,数据装换，排版,底片制作,-,线路底片,材料准备,-,覆铜基板（,FR-4,），环氧树脂，防焊漆,GERBER,预清洗,Clear,-,将基板上的杂志清洗干净,涂膜,-,将感光干膜均匀涂抹在基板上,曝光,-,盖上线路底片进行曝光，感光干膜受到光的照射后开始硬化，紧紧包裹在基板表面的铜箔，形成线路,显影,-,使用碳酸钠溶液洗去未硬化的感光干膜，让不需干膜保护的铜箔露出来,蚀刻,-,使用蚀铜液对没有干膜保护的铜箔进行蚀刻,去膜,（脱膜）,-,将剩余感光干膜去除,检测,-,使用,AOI,进行基板检测,Inner,内层,定位,黑（棕）氧化，烘烤,其目的在于使内层线路板表面上形成一层高抗撕裂强度的黑（棕）氧化铜，以增加内层板在进行层压时的结合能力,排版，压版,磨边,Laminating,压,合,定位,-,以插梢将基板固定于钻孔上,数控钻,-,使用精密数控钻床出要的导通孔,去毛边，通孔电,-,先以重度刷磨及高压冲洗方式清理孔壁中的毛边及粉屑，再以高锰酸钾溶液去除孔壁同面上的胶渣，而后再将基板浸于化学铜溶液中，借着金属的催化作用将铜离子还原沉积于孔壁，形成通孔电路,Drilling,钻孔,将整个印刷电路板电镀一层铜,先将线路板作适当的粗化处理,再将感光绿漆涂覆于板面上,预烘干燥,冷却后送入紫外线曝光机中曝光,以溶剂去除未曝光区域的绿漆,高温烘烤使绿漆完全硬化,将客户所需的文字，商标，零件标号以网版印刷方式印在版面上,再用热烘（或紫外线照射,),方式让文字漆墨硬化,镀铜、,防焊,、文字,常见的,Finish,有,1,）喷锡,-,成本低，但是表面不平整，易造成制程问题，多用于电脑主机板,2,）,OSP,（护铜剂）,-,成本低但是易氧化,3,）镀金,-,品质稳定但成本高,4,）化金,-,可焊性寿命比,OSP,更久，但有墨垫（,Black Pad,）问题,5,）化银,-,可焊性寿命比,OSP,更久，但比化金较差,6,）化锡,在化锡板的制程中必须加入硫脲（,Thiourea,）方能使锡离子逆向取代铜，但是硫脲却有致癌的危险性。此外，硫脲会攻击印刷电路板的防焊层（,Solder mask,），且铜与锡在室温下即会发生反应，因此化锡板也有保存性不佳的疑虑,7,）选化（化金,+OSP,）,-,结合两者优点，制程较复杂且费时间,PCB surface finish,表面处理,将,PCB,以,CNC,成型机械切割成客户所需要的外形尺寸，最后再将,PCB,上的粉屑及表面离子污染物洗净,电流测试（,ICT In Circuit Testing,）,最后视觉检测（,Vision Inspection,）,包装，出货（,packaging,，,shipping,）,成型 电测 检验 出货,PCB Manufacture Process,PCB,制造流程,PCB Manufacture Process,PCB,制造流程,PCB Manufacture Process,PCB,制造流程,制造出合格的,PCB,板,PCB Assembly Types PCB,组装方式,PCB Assembly Types PCB,组装方式,Unavailability of odd shaped,high power,and specialized components.,奇怪形状，高功率，和一些特殊的元件不能用单一的组装技术。,More investment required to setup a full SMT process,建立一个全套的,SMT,制程需要更多的投资。,In many cases it is cheaper to use through hole components,插件元件,在许多情况下是便宜的,THT is more robust and is necessary in certain application,插件在某些应用中更可靠和必要,Why mixed technology PCB assembly,?,为什么,有混合,PCB,组装技术,SMT and Mixed Technology Assembly TypesSMT,和混合组装技术类型,Why Surface Mount Technology?,为什么有表面粘贴技术,Enables significant size and weight reduction,可显着减少尺寸和重量,Provides improvement in electrical performance,改善电气性能,Offers reasonable solution for high pin count ICs,提供高引脚数集成电路,合,理的解决方案,Manufacturing assembly is more easily automated,生产装配更容易自动化,Offers the potential for significant cost reductions,提供了降低成本的巨大潜力,Surface Mount Technology(SMT),表面粘贴技术,(SMT),Surface Mount Technology Performance,表面粘贴技术性能,Prime motivation is increased density and board area reduction,。,主要目的是提高板密度和减少面积,Smaller devices(actives and passives),小体积的主动元件和被动元件,DIPs over 40 pins were impractical,超过,40,支脚的插件元件是不切实际的,Two-sided mounting,两面粘贴,SMT results in a better product SMT,可以生产出一个更好的产品,Same functions for less space,小的空间可以得到同样的功能,More functions for same space,同样的空间，更多的功能,Less electrical signal delays,信号延迟少,Less mass,better vibration resistance,更好的抗震性,Surface Mount Technology(SMT),表面粘贴技术,(SMT),Surface Mount Technology(SMT),表面粘贴技术,(SMT),SMT Components SMT,元件,Surface Mount Technology(SMT),表面粘贴技术,(SMT),SMT Components SMT,元件,直插式封装,直插式封装集成电路是引脚插入印制板中，然后再焊接的一种集成电路封装形式，主要有单列式封装和双列直插式封装。其中单列式封装有单列直插式封装,(Single Inline Package,，缩写为,SIP,和单列曲插式封装,(Zig-Zag Inline Package,，缩写为,ZIP),，双列直插式封装又称,D I P,封装,(Dual Inline Package),，这种封装的集成电路具有两排引脚。适合,PCB,的穿孔安装；,贴片封装,这种封装的集成电路引脚很小，可以直接焊接在印制电路板的印制导线上。贴片封装的集成电路主要有薄型,Q F P(TQFP),、细引脚间距,QFP(VQFP),、缩小型,Q F P(S Q F P),、塑料,Q F P(PQFP),、金属,QFP(MetalQFP),、载带,QFP(TapeQFP),、,J,型引脚小外形封装,(SOJ),、薄小外形封装,(TSOP),、甚小外形封装,(V S O P),、缩小型,S OP(SSOP),、薄的缩小型,SOP(TSSOP),及小外形集成电路,(SOIC),等派生封装。,BGA,封装,(Ball Grid Array Package),又名球栅阵列封装，,BGA,封装的引脚以圆形或柱状焊点按阵列形式分布在封装下面。采用该封装形式的集成电路主要有,CPU,以及南北桥等的高密度、高性能、多功能集成电路。,厚膜封装,厚膜集成电路就是把专用的集成电路芯片与相关的电容、电阻元件都集成在一个基板上，然后在其外部采用标准的封装形式，并引出引脚的一种模块化的集成电路,常用的集成电路封装方法,How are PCBs assembled?,PCBA,怎样组装？,Wave,Solder,波峰焊,Hand,Placement,手摆放,Visual,Inspection,目检,ICT,在线测试,PCB,Preparation,PCB,准备,PCBA,测试,Raw,Component,原始零件,FT,功能测试,Overview of SMT Process SMT,制程概述,SMT Process,SMT,Solder,Printing,锡膏印刷,Pick&,Place,选择和放置,零件,Post,Reflow,回流焊,Solder Printing,锡膏印刷,What is solder printing?,什么是锡膏印刷,Process of transferring solder paste onto the pads of a PCB,by forcing it through mating apertures on a stencil,using a squeegee,。,用刮刀使用压力，使锡膏通过匹配的模具上的小孔，转移到,PCB,的焊盘的过程,.,Circuit Board,线路板,Use to provide interconnect traces between,components,提供元件间的相互连接,Stencil,钢板,Vehicle by which the volume and placement location of solder paste deposition is controlled,控制锡膏流量和放置位置的媒介,Solder Paste,锡膏,Mixture of solder spheres and flux deposited onto pads of circuit board on a controlled volume.After reflow provides electrical,mechanical and thermal dissipative connection between component and board,焊料和助焊剂的混合，定量的转化到线路板的焊盘上。经过回流，提供元件和线路板之间的电气，机械和热耗散连接,Solder Printing,锡膏印刷,Squeegee,刮刀,Critical tool used to“push”paste through the,designated openings.Variations in hardness,flatness,speed,angle and pressure critically,impact quality of the print,用于通过指定的开孔推动锡膏的关键工具。硬度，平整度，速读，角度和压力 关键变量影响印刷的质量。,Printer,印刷机,Machine which deposits solder paste onto,pads on the circuit board,将锡膏放到线路板上的机器,Solder Printing,锡膏印刷,Pick&Place Process,选择和放置零件,A flexible machine that places many different types of components on a PCB,灵活的机器，可以在,一块,PCB,上放置许多不同类型的元件,Most important piece of equipment in the SMT assembly process,在,SMT,组装制程中最重要的一种设备。,Very expensive,很昂贵,Without the use of appropriate feeders and a machine vision system,the placement equipment will not be able to pick&place components,如果没有适当的进料器和机器视觉系统的使用，安置设备将无法取放组件。,It includes features such as:,它包括以下的功能：,Reliable placement accuracy,可靠的放置精度,Vacuum pickup capability,真空提取能力,Automatic component realignment,元件自动对准,Vision system,视觉系统,Transportation system for PCBs PCBs,运输系统,Pick&Place Process,选择和放置零件,Factors influencing the use of automated placement equipment in SMT,在,SMT,中,影响自动贴装设备的使用,的,因素,Handling of components,especially small chips and ultra-fine pitch leaded devices,元件的手动搬运和操作,，尤其是小芯片和超细间距引线的器,件,Throughput requirements,吞吐量需求,Reliability and Accuracy,可靠性和准确性,Quality,质量,Flexibility,灵活性,Pick&Place Process,选择和放置零件,零件进料,PCB,搬运,育龄舰对准,板办对准,放置头,机械手,机壳,Pick&Place Process,选择和放置零件,Normal Pick Up,正常的提取,Z-Axis moves till component is touched Z-,轴移动,直到接触到元件,Then Z-Axis moves back and component is picked up,，然后，,Z-,轴移回原来的地方，,元件被提起来,Touchless Pick Up,无接触的提取,Z-Axis moves to a fixed height above the component Z-,轴移动到元件上方一个固定的高度,Component is sucked out of the pocket,元件被吸出袋外,Post Reflow Process,回流焊,What is post reflow process?,什么是回流焊？,Process of joining metallic surfaces through the mass heating of solder or solder paste,是通过大量加热，使锡膏受热融化从而让表面贴装元器件和,PCB,焊盘通过焊锡膏合金可靠地结合在一起的制程。,Creates a mechanical and electrical connection between the components and PCB,在,PCB,和元件之间创建一种机械和电器的连接,Surface mount components are secured on the surface and are dependent on solder volume for mechanical strength,表面粘贴元件依靠一定量的锡膏由于机械强度被固定在表面,Solder alloy metal is melted to form the connection,合金焊料融化后，形成连接,Liquid solder attaches to the base metals by forming intermetallic compounds,through,the process of wetting,液态焊料由金属化合物，通过润湿流程附着在金属表面。,Post Reflow Process,回流焊,Requirement for soldering,回流焊的需求,Source of Solder Alloy,焊料,-,合金,Source of Heat,热源,Flux,助焊剂（,通常是以松香为主要成分的混合物）,Compatible Metallization,兼容金属,Clean Surfaces,表面清洁,Controlled Process,被控制的流程,Post Reflow Process,回流焊,Surface Mount and Through Hole Solder Joints,表面焊接和通孔焊接,Post Reflow Process,回流焊,In the soldering process,three different heating methods are used,三种不同的加热模式用在焊接制程中。,Conduction,热传导,Convention,热对流,Infrared Radiation(IR),红外辐射,Different heat transfer methods offer different advantages and disadvantages,不同的热传输模式有不同的优势和劣势,Conduction,热传导,Conduction occurs when two solid masses of different temperatures are in contact,with each other,热传导发生在不同温度下的两个固体相互,的接触,Provides uniform product heating as heat will conduct from a hot spot to a cold spot,in the product,供给均匀的热，由于热能将从热的一端传到冷的一端。,Post Reflow Process,回流焊,Convection-,热对流,Convection heat transfer occurs when a fluid(such as air or nitrogen)flows over the,object to be heated,热对流发生在气体吹过目标物（如空气或氮气）。,Two types-Natural Convection and Forced Convection,两种方式,-,自然对流和强制性对流,Natural convection occurs when no flow is being forced over the object,自然对流发生于没有气体被强制流过目标物。,Forced convection requires an external force that pushes or pulls the flow over,the object,强制对流需要一种外部的压力推动或拉动气流流过目标物。,Most soldering ovens today use forced convection as the primary heat transfer method,今天大多数焊接烤箱使用强制对流作为换热模式预热的主要方法,Post Reflow Process,回流焊,Post Reflow Process,回流焊,Infrared Radiation(IR),红外辐射,Infrared radiation(IR)occurs when two bodies of different temperatures are in sight of each other,红外辐射发生与当两种不同温度的物体在相互的视野内,Heat is transferred by the electromagnetic waves generated by the hot body,热被产生于热物体的电磁波转换。,Two important phenomenon with radiation:,两种重要的辐射现象,Absorbtivity:Percentage of infrared absorbed by the PCB and components,吸收：被,PCB,和元件吸收的百分比,Black Body:A body that absorbs all,radiation incident upon its surface,黑体：吸收所有表面辐射的物体,Post Reflow Process,回流焊,Soldering Surface Mount Components,表面粘贴元件,Soldering,Reflow,Vapor Phase,IR,Forced Convection,Wave Soldering,焊接,回流焊,波峰焊,蒸气,红外辐射,强制对流,All the soldered connects,Are created in a single step,所有的焊接在一个步骤完成,The soldered connections are,Created one after another,焊接在一个步骤接着另一个步骤地完成,Soldering Through Hole Components,插件元件,Post Reflow Process,回流焊,Soldering through Hole Components,Simultaneous,Sequential,插件元件,一次性的,连续性的,Simultaneous,Dip soldering,Wave Soldering with solder resist,Post Reflow Process,回流焊,Simultaneous Soldering,一次性的,浸焊,有防焊的波峰焊,Sequential,Iron Soldering,Mini-flow soldering,Light Soldering,Laser Soldering,Flame Soldering,Post Reflow Process,回流焊,Sequential Soldering,连续性的焊接,持续性焊接,烙铁焊,小热风焊,光波焊接,镭射焊接,火焰焊接,波峰焊,是指将熔化的软钎焊料（铅锡合金，锡银铜合金 等），经电动泵或电磁泵喷流成设计要求的焊料波峰,亦可通过向焊料池注入氮气来形成，使预先装有元器件的印制板通过焊料波峰，实现元器件焊端或引脚与印制板焊盘之间机械与电气连接的软钎焊。根据机器所使用不同几何形状的波峰，波峰焊系统可分许多种。,波峰焊流程,：将元件插入相应的元件孔中 预涂助焊剂 预烘（温度,90-1000C,，长度,1-1.2m,）波峰焊（,220-2400C,）切除多余插件脚 检查,Wave Solder,波峰焊,Wave Solder,波峰焊,Wave-solder machine module,波峰焊机器模组,Conveyor,传送带,Spray Fluxer,助焊剂喷洒机,Preheat,预热器,Solder Pot&Nozzles,焊接棒 和焊嘴,Wave Solder,波峰焊,波峰后的,PCBA,焊波,喷洒助焊剂,预热,波峰焊,冷却,Assembly Preparation for Wave Soldering,波峰焊的准备,Fully automated or manual inspection of the assembly to verify:,全部制动或手动目检,Presence or absence of various components,元件的存在和缺件,Component type and orientations,元件型号和方向,Damaged boards,撞板,Bad component clinching on the bottom side,底面的损件,Selective solder masking using temporary liquid solder mask or tape,to prevent solder,from attaching to specific are as of the PCB assembly,选择性焊锡,屏蔽使用临时液态防焊或,胶,带，以防止,焊料,附着在,PCB,组装的,指定的领域。,Adding edge supports for the board,to prevent warping of thin boards,添加边缘支持，以防止薄板,弯,曲,Wave Solder,波峰焊,Wave Solder and Through Hole Assembly Process,波峰焊和插件组装流程,Raw PCB,DIP Insertion,Radial Insertion,Odd-Form Insertion,Apply Temporary solder mask,Is PCB of standard thickness?,Wave Soldering*,Insertion of Temperature Sensitive Components,Selective Soldering of Temperature Sensitive Components,Remove Temporary Solder Mask,Add Board Stiffness,For thin boards,增加板的刚度,Yes,(Standard Thickness=62-mils),标准厚度,空板,插件,径向插入,多种方式插件,运用临时防焊,PCB,是标准厚度吗？,温度敏感元件的插入,温度敏感元件的可选择性焊接,去除临时防焊物,Inspection/Cleaning,目检和清洁,.,No,不是,Wave Solder and Through Hole Assembly Process,波峰焊和插件流程,Thank You,！,