ESD防护原理与体系建立.ppt

ESD防护原理及防护体系建立主讲：李岩主讲：李岩Shenzhen and May 19,2002 1(LI Yan-DNV)第一章第一章 ESD ESD 基础基础 Basics of ESDShenzhen and May 19,2002 2(LI Yan-DNV)课程内容课程内容 (Contents)1.0 1.0 目目标标 (Objectives)2.0 2.0 静电放电静电放电(ESD)ESD)历史历史(History of ESD)3.0 3.0 静电放电静电放电(ESD)ESD)计算计算(ESD Basic formula)4.0 4.0 静电静电 (Whats Static Electricity)5.0 5.0 静电放电静电放电 (ESD)6.0 6.0 静电引发的问题静电引发的问题(Problems by ESD)7.0 7.0 ESD ESD 的控制的控制 (Controlling ESD)Shenzhen and May 19,2002 3(LI Yan-DNV)1.0 1.0 目的目的 (Objectives)n 提供对静电及静电放电提供对静电及静电放电(ESD)ESD)的的 基本理解基本理解 (Basic understanding on Static Electricity&ESD)n 描述关于静电和电子产品的问题描述关于静电和电子产品的问题 (Describe issues about electricity and electronic products)n 提供控制静电的有用工具及体系提供控制静电的有用工具及体系 (Overview of tools and system to control ESD problems)Shenzhen and May 19,2002 4(LI Yan-DNV)2.0 2.0 ESD ESD 历史历史 (History of ESD)n 静电(闪电）使人类恐惧和敬畏(Lightning made human beings frighten)n世纪军事堡垒为防止弹药爆炸采取基本的静电控制(1400s-Began to control in military forts to prevent gunpowder explosions)n年代，造纸厂开始对通过干燥箱的卷筒纸采取基本的接地及离子化处理限制电荷(1860 s-Paper mills employ basic grounding and ionization to limit charge on paper web travelling though dryers)n年代中期，认识到ESD导致电子器件失效，工业界开始注意原因及解决(Mid 1970 s-Recognized as ESD cause device failures in electronics industry)Shenzhen and May 19,2002 5(LI Yan-DNV)3.03.0ESD ESD 计算计算 (Calculations)n基本公式基本公式 (Basic Formula)电量电压电容的关系电量电压电容的关系(Charge/Voltage/Capacitance)电量衰减电量衰减(Charge Decay)能量能量 (Energy)Shenzhen and May 19,2002 6(LI Yan-DNV)基本公式基本公式 (Basic Formula)Q QnV=-V=-C C式中:nQ=电量,单位库仑(1库仑等于6.24x1018个电子)nC=电容,单位法拉nV=电位差,单位伏特 Shenzhen and May 19,2002 7(LI Yan-DNV)电量衰减电量衰减 (Charge Decay)n常见概念-形象化n 在容量系统中,电量衰减的速度是物体容量 和对地电阻的函数(RC)n 衰减时间常数()=RCu 1 =37%初始电量u 5 =99%初始电量Shenzhen and May 19,2002 8(LI Yan-DNV)电量衰减电量衰减 (Charge Decay)Shenzhen and May 19,2002 9(LI Yan-DNV)电阻电阻(Resistance)Resistance)n R=V/IR=电阻(欧姆)V=电压(伏特)I=电流(安培)n 用来测量ESD保护材料(Used to measure ESD protective material)n 测试仪器廉价,易于操作(Easy to test,low cost instrument)Shenzhen and May 19,2002 10(LI Yan-DNV)能量能量(Energy)Energy)n放电能量表示为:E=1/2 CV2 式中:E=焦耳能C=电容V=电压Shenzhen and May 19,2002 11(LI Yan-DNV)4.0 4.0 静电静电(Static Electricity)Static Electricity)n什么是静电?(Whats Static Electricity?)u 静电是固定的(不移动)电荷(Static Electricity is a stationary electrical charge)u 材料表面不平衡的电荷(Static Electricity is caused of electrons on the surface of a material)u 材料损失或者获得电子导致电子不平衡(The electron imbalance occurs when materials either lose or acquire electrons.)Shenzhen and May 19,2002 12(LI Yan-DNV)静电学静电学知识知识 (Static Electricity Knowledge)n 原子(the Atom)u 物质由原子构成.原子又由包含质子和中子的原子核构成,环绕原子核的是电子.通常原子保持电中性.(All matter consists of a collection of atoms.The atom is comprised of a nucleus containing protons and neutrons.Orbiting the nucleus are electrons.The atom is normally electrically neutral.)Shenzhen and May 19,2002 13(LI Yan-DNV)静电学静电学知识知识 (Static Electricity Knowledge)n正电荷，负电荷正电荷，负电荷(Positive,Negative Positive,Negative Charge)Charge)n带电体带电体(ChargedCharged matter/body)matter/body)n电量电量(Charge Capacity)-Charge Capacity)-物体所带电量的多物体所带电量的多少少n电荷守恒定律电荷守恒定律(Law of Charge Law of Charge Conservation)-在任何物理过程中电荷的代数和是守恒的。在任何物理过程中电荷的代数和是守恒的。Shenzhen and May 19,2002 14(LI Yan-DNV)带电体带电体 (Charged matter/body)Charged matter/body)n 导体导体(conductor)conductor)、绝缘体绝缘体(Isolator)Isolator)、半导半导体（消散体体（消散体DissipativeDissipative）材料材料测试原理测试原理(Material Test Principles)Material Test Principles)体，面电阻体，面电阻/电阻系数电阻系数；面电阻面电阻 s s=2 2/lnln(D2/D1)(D2/D1)R R 带电性能带电性能 衰减速度衰减速度 电场电场Shenzhen and May 19,2002 15(LI Yan-DNV)静电学静电学知识知识 (Static Electricity Knowledge)n静电产生方式(Charging Methods):u 摩擦起电(Triboelectrification)u 离子溅射(单一极性)(Ion Bombardment(single polarity)u 接触充电(Contact Charging)u 感应或极化(Induction or Polarization)u 其他-剥离，破裂，电解，压电，热电，.(Others-peel off，cracking，electrolyse，piezoelectricity，thermoelectricity，.)Shenzhen and May 19,2002 16(LI Yan-DNV)摩擦起电摩擦起电 (TriboelectrificationTriboelectrification)n当液体,固体和气体颗粒接触又分离.起电量受下列影响:(Charge generated by the contact and separation of liquids,solids and particulate carring gases.The magnitude of the charge is influenced by:)u 接触紧密度(Intimacy of contact)u 分离速度(Speed of separation)u 摩擦运动(Rubbing motion)Shenzhen and May 19,2002 17(LI Yan-DNV)摩擦起电摩擦起电 (TriboelectrificationTriboelectrification)Shenzhen and May 19,2002 18(LI Yan-DNV)摩擦起电摩擦起电 (TriboelectrificationTriboelectrification)Shenzhen and May 19,2002 19(LI Yan-DNV)摩擦起电摩擦起电 (TriboelectrificationTriboelectrification)Shenzhen and May 19,2002 20(LI Yan-DNV)摩擦起电摩擦起电 (TriboelectrificationTriboelectrification)n摩擦起电族系摩擦起电族系n 玻璃玻璃n 尼龙尼龙n 羊毛羊毛n 丝绸丝绸n 纸张纸张n 聚亚氨脂聚亚氨脂 PolyuerethanePolyuerethanen 棉花棉花n 木材木材n 硬橡胶硬橡胶n 聚酯薄膜聚酯薄膜 MylarMylarn 丙烯酸丙烯酸 AcrylicAcrylicn 聚酯聚酯 PolyesterPolyestern 铁弗龙铁弗龙 TeflonTeflon+(+(失电子失电子)-(-(得电子得电子)Shenzhen and May 19,2002 21(LI Yan-DNV)离离 子子 溅溅 射射 (Ion Bombardment)Shenzhen and May 19,2002 22(LI Yan-DNV)接触充电接触充电(Contact Charging)Contact Charging)n带电物体通过接触将电荷传导给未带电物体(Charge will b e transferred to a previously uncharged object by contact with an object holding a charge)u 带电绝缘体仅能从较小面积释放电荷(A charged insulator will only release charge from a small area.)u 带电导体能释放大量电荷给另一导体(A charged conductor can release a substantial amount of charge by contact with another conductor.)Shenzhen and May 19,2002 23(LI Yan-DNV)接触充电接触充电(Contact Charging)Contact Charging)Shenzhen and May 19,2002 24(LI Yan-DNV)感应感应(Induction)Induction)n发生于带电体 接近 导体时(Occurs when a charged object is brought close to a conductor):u 带正电的物体(如绝缘体)吸引导体中的电子u 这种电子运动导致导体中的电荷分离(但导体中总电量为零)n 高斯定理:1 E E=E E d S=S=-qi 0Shenzhen and May 19,2002 25(LI Yan-DNV)感应带电感应带电 (Charging by Induction)Shenzhen and May 19,2002 26(LI Yan-DNV)感应带电感应带电 (Charging by Induction)Shenzhen and May 19,2002 27(LI Yan-DNV)感应带电感应带电 (Charging by Induction)Shenzhen and May 19,2002 28(LI Yan-DNV)5.0 5.0 静电释放静电释放(Electrostatic Discharge)n定义定义:静电释放静电释放(ESD)-ESD)-电荷在不同电势电荷在不同电势物体间的转移和运动物体间的转移和运动.(the transfer or movement of charge between objects that are at different electrical potentials)n 例如例如:u 汽车车门电击汽车车门电击(Shock received from car)u 闪电闪电(lightning)Shenzhen and May 19,2002 29(LI Yan-DNV)器件敏感度 Device Sensitivity 如何知道是否需要静电防护？首先应确定敏感度。四个放电模型Shenzhen and May 19,2002 30(LI Yan-DNV)ESD ESD 放电模型放电模型 (Discharge Models)n 人体模人体模式式(Human Body Model)n 机器模机器模式式(Machine Model)n 带电器件模带电器件模式式(Charged Device Model)n 场感应模场感应模式式(Field Induced Model)Shenzhen and May 19,2002 31(LI Yan-DNV)人体模式人体模式(Human Body Model)带电人体对敏感器件的放电(Discharge occurs from a charged person to an ESD sensitive product)Shenzhen and May 19,2002 32(LI Yan-DNV)HBM 模型器件敏感度0-1，999V-微波器件，分立MOSFET，SAW，JFETS，CCDS，TFR，。2，000-3，999V-分立MOSFET，JFETS，OP AMPS，ICS，VHSIC，HYBIDS。Shenzhen and May 19,2002 33(LI Yan-DNV)机器模机器模式式(Machine Model)机器上某带电部位向ESD敏感产品放电(Discharge occurs from a charged piece of equipment to an ESD sensitive product.)Shenzhen and May 19,2002 34(LI Yan-DNV)带带电器件模式电器件模式 (Charged Device Model)n带电器件向另一导体放电带电器件向另一导体放电(人人,其它器件其它器件)(Discharge occurs from a charged device to another conductor(Person,another device)Shenzhen and May 19,2002 35(LI Yan-DNV)场感应模型场感应模型(Field Induced Model)n 场感应模式:接地的ESD敏感元件处于静电场中(ESD sensitive device is grounded in presence of a static field)Shenzhen and May 19,2002 36(LI Yan-DNV)n 静电引致爆炸(Static Initiated Explosions)n 吸引灰尘和绒毛(Dust and Lint Attraction)n 设备死机(Equipment upset(required reset)n 严重损坏(Catastrophic failure)n 人员触电(Personnel Shock)6.0 6.0 静电引起的问题静电引起的问题 (Problems associated with static electricityShenzhen and May 19,2002 37(LI Yan-DNV)静电引致爆炸静电引致爆炸 (Static initiated explosions)n 化工及油漆工业(Chemical and coating industries)n 烟花业(Pyrotechnics)n 弹药和炸药(Munitions and explosives)n 石油和燃料(Petroleum and fuel processing)n 医院(Hospitals)n 粮仓(Grain storage)Shenzhen and May 19,2002 38(LI Yan-DNV)吸引灰尘和绒毛吸引灰尘和绒毛(Dust and Lint Attraction)常发生于图像,图片美术,和电子工业(Problems in photographic,graphic arts electronics industries)Shenzhen and May 19,2002 39(LI Yan-DNV)Shenzhen and May 19,2002 40(LI Yan-DNV)设备死机设备死机 (Equipment Upset)n静电引起的电磁干扰(EMI from a static discharge)n 对设备直接放电(Direct discharge to equipment)Shenzhen and May 19,2002 41(LI Yan-DNV)人员触电人员触电(Personnel Shock)Personnel Shock)n不同程度存在于塑料及其它工业(Refers to level of shock experienced in manufacturing of plastics and other industries)n 严重触电可以导致肌肉反射收缩,甚至跌倒.(Severe shock may cause an involuntary muscle retraction that can result in a fall)Shenzhen and May 19,2002 42(LI Yan-DNV)严重损坏严重损坏(Catastrophic failure)Catastrophic failure)n 电子设备或ESD敏感产品不再达到设计规格(Electronic equipment or other ESDS products no longer perform to design spec.)n 以下带电体导致的ESD损坏(ESD damaged by charged):u 人员(People)u 设备(Equipment)u ESD 敏感产品(ESDS products)Shenzhen and May 19,2002 43(LI Yan-DNV)7.0 7.0 控制控制ESDESD (Controlling ESD)(Controlling ESD)n 接地(Grounding)n 预防(Prevention)n 电荷中和(Charge Neutralization)n 等势联接(Equipotential Bonding)Shenzhen and May 19,2002 44(LI Yan-DNV)接地接地(Grounding)Grounding)n 将环境中全部导体接地,通过(Take all conductors in environment and connect them to electrical ground via):u 静电带(Wrist)u 导电地板/工作鞋(Conductive flooring/footwear)u 工作台及设备表面接地导线(Conductive ground wires for work and equipment surfaces)n 注:建议固有阻值台面使CDM减到最小.Shenzhen and May 19,2002 45(LI Yan-DNV)预防预防(Prevention)Prevention)n不要容许电荷聚集(Dont allow the buildup of charge)u 恒久接地(Constant grounding)u 采用低充电材料(Use of low charging material)u 消除不必要绝缘材料(Elimination of unnecessary insulative material)Shenzhen and May 19,2002 46(LI Yan-DNV)电荷中和电荷中和 (Charge Neutralization)平衡式离子发生器 (Balanced Air Ionizer)Shenzhen and May 19,2002 47(LI Yan-DNV)已带负电板已带负电板Shenzhen and May 19,2002 48(LI Yan-DNV)等势联接等势联接(EquipotentialEquipotential Bonding)Bonding)电气连接系统中所有单元,消除电势差Shenzhen and May 19,2002 49(LI Yan-DNV)静电防护设备静电防护设备 (Briefing for ESD preventive equipment)Briefing for ESD preventive equipment)Shenzhen and May 19,2002 50(LI Yan-DNV)Shenzhen and May 19,2002 51(LI Yan-DNV)