BGA-介绍.ppt

DELTA NETWORKSBGA 簡介&特性分析SMT Technology SpreadDELTA NETWORKS 何謂BGA?其構造如何?BGABGA簡介Fig 1.1 A cross-section of a PBGA 為面陣列構裝(area array packaging)之產品 率先問世之 BGA 為 Motorola OMPAC(1990)DELTA NETWORKS 目前BGA可分成那幾類?如何區分?BGABGA 種類 PBGACBGA?以構裝型態而言,共分 全陣列(Full-)周 邊陣列(Perimeter-)交錯陣列(Staggered-)以構裝材料而言,共分 PBGA(Plastic Ball Grid Array)CBGA(Ceramic Ball Grid Array)DELTA NETWORKSBGA-Surface Mount ComponentBGADescription:Ball Grid Array:PBGA Plastic BGA,TBGA Tap BGA,CBGA Ceramic BGA,CCGA Ceramic Column Grill ArrayClass letter:U,IC,AR,C,Q,RLead Type:Ball Grid(Column Grill for CCGA)#of Pins:25-625 Body Type:Plastic,metal or ceramicLead Pitch:0.5 mm to 1.27 mm(50 mils)Orientation:Dot,notch,stripe indicate pin 1 and lead counts counterclockwise.PBGAPlastic SubstrateCCGA63Sn-37PbCeramic Substrate10Sn-90PbDELTA NETWORKSBGA-Surface Mount ComponentDELTA NETWORKSBGA-Surface Mount ComponentDELTA NETWORKS 為何要使用BGA而非QFP?優劣如何?BGABGA 優劣 BGABGAQFPQFP PITCH較大,作業簡易實裝具泛用性表面實際密度高表面實際良率高電氣特性佳 同樣腳數體積縮小約40%腳易曲折變形 Fine Pitch開發技術難 不具泛用性 約1/2左右DELTA NETWORKS 標準BGA之 Solder Bump 共分那幾類?BGABGA 錫球 Eutetic Solder(63/37)Hi-Temp Solder(10/90)Fig 2.2 BGA之 Solder Bump 之種類DELTA NETWORKS 何謂NSMD及SMD?BGA SMD:Solder Mask Defined NSMD:Non Solder Mask Defined PAD 防焊墊DELTA NETWORKS NSMD及SMD有何差異&優缺?BGAPAD 防焊墊DELTA NETWORKSMSD:Moisture Sensitive Devic 濕度敏感元件濕度敏感元件 MSL:Moisture Sensitive Level 濕度敏感等級濕度敏感等級 MSL有六個等級有六個等級:msl1-msl6 BGA-保存保存DELTA NETWORKSMSD的工作壽命的工作壽命(等級分辨方法等級分辨方法).Msl123456工作環境工作環境 工作壽命工作壽命85%RH 不受限制不受限制30C/60%RH 一年一年30C/60%RH 一周一周30C/60%RH 72小時小時30C/60%RH 24小時小時30C/60%RH 上線前必須烘烤上線前必須烘烤DELTA NETWORKS MSD的儲存條件的儲存條件1.真空包裝真空包裝 溫度溫度255C 濕度濕度555%RH 2.非真空包裝非真空包裝 溫度溫度255C 濕度濕度30%RHDELTA NETWORKS真空封裝機真空封裝機DELTA NETWORKS封裝封裝OK之物料之物料DELTA NETWORKS烘烤箱烘烤箱DELTA NETWORKSBGA-烘烤包裝形式包裝形式 濕度濕度 時間時間 Tray 125 5C 24小時小時 Tape/Tube 405C 192小時小時DELTA NETWORKS 為何使用BGA之前需經烘烤?BGABGA 烘烤 因 BGA 本身屬於濕氣敏感元件 根據 JEDEC 水氣含量件分級表,濕氣敏感元件 曝露的時間超過其表上時間時,在烘烤過程中易 產生爆米花(POPCORN)效應DELTA NETWORKSBGA0.0300.0156hr24hrDELTA NETWORKSBGABGA 烘烤 BGABGA之之之之烘烤條件及方式為何烘烤條件及方式為何烘烤條件及方式為何烘烤條件及方式為何?BGABGA之烘烤共分兩種之烘烤共分兩種,即高溫及低溫烘烤即高溫及低溫烘烤 高溫烘烤目地在上線作業前去除高溫烘烤目地在上線作業前去除BGABGA內之濕氣內之濕氣,其其 條件為條件為125125,時間時間624624hrhr 低溫烘烤目地在避免烘烤完卻未及上線之低溫烘烤目地在避免烘烤完卻未及上線之BGABGA,於於 開放環境中二次受潮開放環境中二次受潮,其條件為其條件為555,555,時間不限時間不限 嚴謹正常之高溫烘烤條件應為嚴謹正常之高溫烘烤條件應為125125,時間時間2424hrhr左圖為BGA及PCB烘烤專用之烤箱,其溫度範圍為50250,烘烤時間限制999hrDELTA NETWORKSBGA-印刷鋼板開口印刷鋼板開口CSP開孔經驗開孔經驗1.CSP 球徑：球徑：0.375mm 外形尺寸外形尺寸:4.7mmX4.6mm.Pitch:0.50mmPitchPitch小，小，故對鋼板的故對鋼板的選擇要求較高選擇要求較高.2.對應焊盤尺寸對應焊盤尺寸:0.35mm3.3.不同開孔方式比較不同開孔方式比較 鋼板厚度鋼板厚度:0.10:0.10mm mm 開孔正方形倒圓角開孔正方形倒圓角足夠的錫膏量足夠的錫膏量良好的下錫性能良好的下錫性能鋼板厚度鋼板厚度:0.12:0.12mm mm 開孔形狀及尺寸開孔形狀及尺寸:圆形，圆形，直徑直徑0.270.27mmmmPCBA:0.241mmA:0.241mmB:0.254mmB:0.254mmC:0.10mmC:0.10mm面积比面积比 *r*r/(2r*0.12)=0.27/0.48 =0.563 1.33CPK 1.33印刷精度控制印刷精度控制:管控錫膏印刷精度管控錫膏印刷精度,測量值為偏移量測量值為偏移量.管制管制 目標目標CPK1.33 CPK1.33 錫膏印刷成型控制錫膏印刷成型控制:管制項目為錫膏成型管制項目為錫膏成型,控制錫膏在控制錫膏在PCBPCB 上的成型上的成型,一般要求同一點位連續一般要求同一點位連續1010PCSPCS中有中有“狗耳狗耳朵朵”現象的數量不得大于現象的數量不得大于2 2DELTA NETWORKS常用錫膏合金成份及融解溫度常用錫膏合金成份及融解溫度Eutectic:Sn63/Pb37 Tmelt=183o Cw/Silver:Sn62/Pb36/Ag2 Tmelt=179o CNo Lead:Sn96.5/Ag3.5 Tmelt=221o CHigh Temp:Sn10/Pb88/Ag2 Tmelt=268o C-302o CDELTA NETWORKSASTM Mesh 尺寸Designation(um)(in)Type1(200)740.0027Type2(250)580.0023Type3(325)440.0017Type4(400)370.0015Type5(500)300.0012Type6(625)200.00078325400500(-325+400)ASTM:American Society for Testing and MaterialsMesh(網目):每一方寸內有多少錫球例:使用 TYPE 3 角距為 20 mil,其錫粒子為 1.7 mil(0.0017 in)錫膏顆粒尺寸錫膏顆粒尺寸DELTA NETWORKS錫膏檢驗BGA Joint Photo Under X-RAY&3DDELTA NETWORKSHead unitParts recg.camera-貼片零件種類:1005mm Chip55*55mm QFP L150*W55*H25,BGA,CSPBGA-貼片DELTA NETWORKS錫膏錫膏溫度曲線溫度曲線BGA-回流&Profile DELTA NETWORKS 迴焊曲線之探討?BGA迴焊曲線ABCDELTA NETWORKSBGABGA 平整度Solder Bump剝離點PCB 變形方向Reflow conveyFig 2.1 Solder Side經 Reflow後之變形 BGAPWB Solder Side在經在經 SMT Reflow 時產生向下時產生向下之彎曲變形之彎曲變形,導導 致致BGA上之上之Solder Bump產生應力集中而易剝離產生應力集中而易剝離PCB上上 之之PadDELTA NETWORKSBGABGA 二次迴焊Solder Bump剝離點PCB 變形方向經經 SMT Reflow 時產生向上時產生向上變形之變形之PCB再經再經Wave Soldering 產生產生PCB軟化而向下彎曲軟化而向下彎曲,此時此時BGA端端電極電極已經歷二次應已經歷二次應 力力破壞破壞,最易最易剝離剝離Reflow conveyFig 2.2 PCB經 Wave Solderig 後之變形 BGAPWBDELTA NETWORKS BGA 組裝後變形之可靠度試驗BGA可靠度試驗 可承受之 Applied Force 愈大,可靠度愈佳?Fig 3.1 PCB 可靠度試驗三點檢測法DELTA NETWORKS BGA 組裝時常發生何問題?BGA組裝問題 Solder Bump Void Solder Bump Short Placement Shift Solder Land Open Reliability Aging PopcornElongated jointsDELTA NETWORKS Solder Bump VOID 現象(6224M)BGAVOID 效應 2D X-Ray of 6224M 掃瞄結果掃瞄結果DELTA NETWORKS 何謂VOID及效應?現象原因為何?BGAVOID 效應X-Ray 斷層掃瞄結果VoidDELTA NETWORKSBGAVOID 效應DELTA NETWORKS VOID效應在PBGA及CBGA等有何差異?BGAVOID 效應DELTA NETWORKS 如何避免VOID效應?BGAVOID 效應 提高助焊劑活性與助焊劑含量 調整迴焊曲線縮短作用時間 避免PCB Land 受潮氧化(tumbling time)避免Solder Ball 受潮氧化 DELTA NETWORKSBGAVOID 效應DELTA NETWORKS 何謂爆米花 POPCORN 效應?BGAPOPCORN 效應因因因因BGABGA內含之水氣造成爆米花現象內含之水氣造成爆米花現象內含之水氣造成爆米花現象內含之水氣造成爆米花現象DELTA NETWORKSBGADELTA NETWORKSBGADELTA NETWORKSBGADELTA NETWORKSBGADELTA NETWORKSBGADELTA NETWORKS 何謂Self Alignment 效應?BGA自行對位ShiftSolderingAlignment 所謂自行對準效應,即Solder Bump在對位時的偏移 會因 錫球達熔點時的表面張力而自行對準 NSMD PBGA 對位限制為1/2 球徑,SMD小於 1/2 球徑,但 以CSP則僅容許2之誤差 DELTA NETWORKS Self Alignment 在SMD及NSMD 之差別?BGAPAD 防焊墊DELTA NETWORKSD301D301有鉛有鉛無鉛無鉛DELTA NETWORKS5 X-RAYBGA 空焊空焊比周圍球偏大比周圍球偏大BGA-Rework&inspectionDELTA NETWORKS球面倒刺球面倒刺(實為實為Carry 殘留殘留)歪向另一歪向另一顆錫球顆錫球,導致導致soldering時時 短路短路issuesocketDELTA NETWORKS檢查-Area Array/Ball Grid Array A BGA inspection criterion assumes that the reflow process has been qualitied to insure proper reflow temperatures have been achieved under the component.X-ray may be used as an inspection tool.Target:*Solder terminations are smooth and rounded,with a clearly defined boundary,have no voids,are of the same diameter,volume,darkness and contrast.*Registration is straight and shows no pad overhang or rotation.*No solder balls present.DELTA NETWORKS Area Array/Ball Grid Array DELTA NETWORKS Area Array/Ball Grid Array Without substantial documented reliability data at the time of publication of this revision,the criteria presented below were established by the experience and consensus of the IPC-A-610 committee,and they are not based on significant reliability data.This is suggested as a starting point for acceptance criteria.Acceptable:*Less than 25%overhang Class 1,2,3 Process Indicator:*25%50%overhang.Class 2,3 Defect:More than 50%overhang.Class 1,2,3DELTA NETWORKS Area Array/Ball Grid Array DELTA NETWORKS Area Array/Ball Grid Array Process IndicatorSolder balls bridging up to 25%of the distance between any two termination Class 1,2,3 *Solder balls that do not violate minimum electrical clearance.Defect:*Solder bridge.*Dark spots in X-ray view that bridge between solder joints(Provided they can not be attributed to circuitry or components underneath the BGA.)*Solder opens *Missing solder *Solder balls that bridge more than 25%of the distance between the leads.*Solder ball that violate the minimum electrical clearance.*Solder joint boundary lacks definition and appears fuzzy or blends in with background(may indicate insufficient reflow)DELTA NETWORKS Area Array/Ball Grid Array DELTA NETWORKS Area Array/Ball Grid Array Process development such as those listed below for BGA attachment critical for performance of the attachment technology.IPC-SM-785(or equivalent)provides guidelines for accelerated reliability testing of surface mount attachments The following guidelines are provided as assessment criteria for the attachment technology process.Without substantial documented reliability data at the time of publication of this revision,no acceptability criteria are provided.DELTA NETWORKS Area Array/Ball Grid Array Acceptable:*Less than 10%voiding in the ball to board interface.Class 1,2,3 Process Indicator:*1025%voiding in the ball to board interface.Voiding in the BGA solder ball to board interconnection up to 25%may or may not be a reliability issue and should be determined in your process development.BGA solder joint reliability studies performed at some industry locations show that limited voiding in BGA balls does not impact long term reliability.Class 1,2,3 Defect:*More than 25%voiding in the ball to board interface.DELTA NETWORKS Area Array/Ball Grid Array Defect:*Incomplete solder reflow of solder paste Class 1,2,3 *Fractured solder connection.Class 1,2,3.DELTA NETWORKSBGABGA 缺點1.1.Rework(Repair)Rework(Repair)不易不易,程序複雜費時程序複雜費時2.2.產品作業後無法以目檢察覺不良產品作業後無法以目檢察覺不良(X-Ray,ICT)X-Ray,ICT)3.3.作業條件嚴苛作業條件嚴苛(IRIR,環境環境)5.5.ICTICT導入時導入時,測試點要全拉出至元件外測試點要全拉出至元件外6.6.ReworkRework後之良率不高且成本昂貴後之良率不高且成本昂貴 BGA BGA 各項缺點分析各項缺點分析:4.4.PCB LayoutPCB Layout受限制受限制,零件內零件內MaskMask要完整要完整,且需且需 預留預留Rework SpaceRework SpaceDELTA NETWORKS