1、1laser钻孔培训教材 随着PCB向微型和高密度互连的方向发展，越来越多制板采用微导孔的连接方式实现高密度互连，而目前制作微导孔的主要方法是laser drill。如何利用现有镭射钻机制作出各种高质量的microvia，是现在PCB制造的迫切任务。1、LASER分类100 nm 5th H,4th H,3rd H,Ar-Ion 2nd H,Nd:YAG Nd:YAG Nd:YAG Nd:YAG Nd:YAG Nd:YLFWavelength212 nm266 nm355 nm488 nm532 nm1064 nmVISIBLEINFRAREDULTRAVIOLET1000 nm10,000
2、nm400 nm750 nm1321 nm光谱图 激光类型主要包括红外光红外光和紫外光紫外光两种；2、常见的LASER激发方式1)LASER 类型UV2)激发介质YAG3)激发能量发光二极管4)代表机型：ESI 53202)LASER 类型 IR（RF-Radio Frequency）激发介质密封CO2气体激发能量高频电压代表机型：HITACHI LC-1C21E/1C3)LASER 类型 IR（TEA-Transverse excited atmospheric横波激励）激发介质外供CO2气体激发能量高压电极代表机型：SUMITOMO LAVIA 1000TW3.1、CO2的成孔原理利用红外
3、线的热能，当温度升高或能量增加到一定程度后，如有机物的熔点、燃点或沸点时，则有机物分子的相互作用力或束缚力将大为减小到使有机物分子相互脱离成自由态或游离态，由于激光的不断提供能量，而使有机分子逸出或者与空气中的氧气燃烧而成为二氧化碳或水气体而散离去，由于激光是以一定直径的红外光束来加工的，因而形成微小孔。Absorptionand HeatingThermalConductionLightMeltingLiquidInterfaceVaporizationPlasma Production固态Nd：YAG紫外激光器发射的是高能量的紫外光光束，利用其光学能(高能量光子)，破坏了有机物的分子键(如
4、共价键)，金属晶体(如金属键)等，形成悬浮颗粒或原子团、分子团或原子、分子而逸散离出，最后形成盲孔。吸收吸收破坏分子破坏分子(原子原子)键键成孔成孔长链大分子长链大分子小粒子逃逸小粒子逃逸3.2、UV的成孔原理4、常见LASER的加工材料 Epoxy FR4 ARAMID COPPER BTv现已加工的介质材料包括：RCC、1X1080、2X1080、2116、2X106、ARAMID吸收率吸收率波长波长(um)ResinMatte CuGlassUVIRVISIBLE00.10.20.30.40.50.60.70.80.910.20.30.4 0.5 0.60.7 0.80.911.1 1.
5、2各种材料都吸收树脂吸收红外光强玻璃反射铜反射由于不同材料对各类激光的吸收均不相同，导致LASER加工混合材料时的困难。4.1、不同材料对波长的吸收情况（2000版本）4.2、不同材料对波长的吸收情况（2001版本）Aspect Ratio500 450 400 350 300 250 200 150 100 50 mmThru ViasBlind Vias10:11:1.1:1UV YAGCO2Photo-viaMechanicalDrill5、各种方法加工孔直径的范围我司现有 Laser 钻机HITACHI LC-1C21E/1CLC-2F21SE/1CLC-2F212SE/2CLC-2G
6、212E/2CLC-2G212BE/2CSUMITOMOLAVIA 1000TWESI53205330 ESI 5320v高频率低功率脉冲v 固态激光激发装置，无须外部供气v“冷光”，产生热量少Hitachiv RF Excited 密封气体激发v 无须定期换气v 每四小时需做精度校正SUMITOMO v 外部供气v 须定期换气v 加工时有能量检测和补打功能ESI UV Laser对位系统对位系统1内层靶标对位内层靶标对位UV Laser刮内层靶标图形刮内层靶标图形定位补偿方法4 points allow correction of x-y offset,rotation,scale,and
7、keystone15.7 mil Through Hole3 mil Hole8 mil Pad40 mil PadESI UV Laser对位系统对位系统2通孔对位通孔对位1.对位标靶-圆形2.对位补偿类似ESIHITACHI&SUMITOMO Laser对位系统对位系统Conformal Mask靶标对位靶标对位Laser BeamGalvoUV LaserCO2 Laser光学系统光学系统Copper surface is cleaned and texturedESI UV Laser的钻孔参数的钻孔参数:Step One:Drill CopperStep Two:Remove Die
8、lectric25mm50-100mmFocused spotSmall spot sizeHigh energy densityDe-focused spotLarger spot sizeLower energy densityStop on inner copper layerDielectricCopperPlanesPunchingDielectricCopperPlanesTrepanningSpiralingDielectricCopperPlanesESI UV Laser的钻孔参数的钻孔参数:Cycle Mode Burst ModeStep ModeHitachi&Sumi
9、tomo Laser的钻孔参数的钻孔参数:即对在一个区域内所有的孔进行第一个脉冲加工，完毕后，再进行第二个脉冲加工，如此类推。即对一个孔进行所有的脉冲加工后，才对下个孔进行加工。钻孔速度钻孔速度 HITACHImax 1200脉冲/秒 SUMITOMOmax 1000脉冲/秒 ESI 15K30K70K脉冲/秒一阶盲孔：A、CO2 laser drillB、CO2 laser direct drillC、UV direct drillD、UV+CO2 laser drill二阶盲孔(钻Stacked via)：A、UV Direct drillB、UV+CO2C、Conformal mask+
10、CO2+UVD、UV+Conformal mask+CO2五、Microvia 缺陷分析 -缺陷类型缺陷类型 -产生原因和影响产生原因和影响 -解决方法解决方法(1)Under Cut(2)Delaminate(4)Remained Glass Fiber(5)Remained Resin(8)Void(7)Damage(6)Micro Crack Barrel Shaped Inner HoleLaser 盲孔缺陷盲孔缺陷 PROBLEMS Under Cut Delaminate Cause and Effect Heat accumulation from RCC copper surf
11、ace Impact to the RCC surface by Laser Beam (1)Under Cut(2)Delaminate Solution Short pulse width Reduce the pulse energyLASER Beam PROBLEMS Barrel Shaped Inner Hole Cause and Effect Reflection from hole bottom Incorrect position of Laser mode(single mode)to the hole Barrel Shaped Inner HoleReflectio
12、n LASER Beam abSingle Mode Solution Short pulse(less than less)The best suited number of shots Multi-mode BeamSingle-modeMulti-mode(top-flat)PROBLEMS Remained Glass Fiber Cause and Effect Difference Nature against heat between resin and glass Solution High peak power processing Cycle-mode processing
13、(4)Remained Glass Fiber PROBLEMS Remained Resin Cause and Effect a.Very thin smeared resin on the bottom of hole not reach sublimation point(5)Remained Resinb.Unsuitability of resin thickness c.Single-mode processing60m80md.Unsuitability of LASER pulse energy e.Incorrect position of LASER BeamAccura
14、cy of XY tableAccuracy of ScannersAlignment Accuracy against PWB elasticityPWB warp PROBLEMS Micro Crack Cause and Effect The pressure from resin sublimation by LASER(6)Micro CrackSolution -Short Pulse(less than less)-The best suited shape of LASER wave -The best pulse energy adapt to nature of mate
15、rial(Standard:about 10J/cm2,pulse width less than 1 us)PROBLEMS Damage Void Cause and Effect a.If the pulse width(irradiation time)is long,the temperature of substrate surface is risen up.(8)Void(7)Damageb.Center portion of Copper foil have damage due to Single Beam Solution Short Pulse Multi-Mode BeamCenter damageThe quality of McroviaCO2Laser drill RCC CO2Laser drill aramidCO2Laser drill FR4
