BGA返修和工作原理介紹.ppt

1、,BGA / SMD Rework Center,ERSA IR 500 A and PL 500 A,BGA Repair: a better understanding can reduce fears, reduce costs, and guarantee process control,Density and performance requirementsDriving IC packing toward the size of the bare die,Trends in Flip Chip use,The Global Trend to Area Array Packages,

2、BGA,CSP, Flip Chip: Structural Designs,BGA Production - Collapsible and Non-collapsible Area Array Packages,In general, eutectic solder balls (Sn63Pb37) are always used for area array packages except in the case where the weight of the component is greater than the surface tension of the molten ball

3、s during reflow. A CBGA (ceramic BGA) is a typical example of a component that could not be “carried“ by the surface tension of the solder balls during the reflow process. In this case, a high melt ball, for example Pb90Sn10, is used because it will remain solid during the normal reflow process.,Bal

4、l Comparison Photos,Comparison of Installed PBGA to a CBGA,The above figures detail the different wetting zones, and wetting angles between a PBGA and CBGA and their respective joints.,The Soldering Process - The Intermetallic Bond and itsRelation to Reflow Temperature,The heart of the solder joint

5、Source: R.J. Kleinwassink, Soldering in the electronics,The lasting mechanical connection can only be achieved when tin-lead (solder) is introduced to form a lasting intermetallic bond between the lead and land and both are heated to approx. 30C above the melting point of solder.,Scanning electron m

6、icrograph (SEM) of fractured intermetallic layers of a solder joint. Cu3Sn (e-phase) and Cu6Sn5 (n-phase) make up the intermetallic layers.,Typical Reflow Profiles,Infrared-soldering. Temperature/time-profile (lead-temperature).Full-line: typical process / dotted-line: process limits,Temperature-tim

7、e curves obtained in a hot-air circulation oven. Source: R.J.Klein-Wassink,Reflow solder profile CECC 00 802: CECC Standard Method for the Specification of Surface Mounting Components (SMDs) of Assessed Quality.,A. BGA solder ball (Sn63PB37) placed on pad before reflow process begins. Stand-off heig

8、ht is, for example, 1.0 mm (ball shape under component is perfectly spherical, surface is smooth and dull).,B. Reflow process begins until melting point of solder ball is reached (183C), gravity acts on component and causes an initial or single drop: Stand-off height is 0.8 mm (ball shape is vertica

9、lly elongated, surface is rough and matt).,C. Peak temperature is reached in the reflow process allowing for complete and proper wetting of entire pad. A second or double drop occurs: stand-off height is 0.5 mm (ball shape is horizontally pressed or somewhat elliptical, surface is smooth and shiny).

10、,BGA Production - Typical Physical Effects during a Reflow Process,The typical physical effects during the reflow process of a PBGA are graphically shown in the figures below with regards to the stand-off height and wetting angle.,Double Drop Effect by BGA/CSP/Flip Chip (Sn63Pb37 Balls),1st Drop2nd

11、Drop,Graphic depicts a non-solder mask defined (NSMD) pad,Note: Life cycle test results show that NSMD pad on both board and package give superior performance to when solder mask defined (SMD) pads are used. Source:Reliability of BGA Packages in an Automotive Environment, Roger Rrgren, Per-Erik Tege

12、hall and Per Carlsson, IVF - The Swedish Institute of Production Engineering Research, www.ivf.se,BGA Double Drop Effect Documented by Philips CFT,Source: BGA Joint Formation, Jan Kolsters, Philips CFT, Eindhoven, Netherlands, May 2000,Video clip of BGA joint formation revealing the double drop effe

13、ct. The video was generated using the ERSASCOPE Inspection System.,Click here to begin video,A cross-section of a PBGA 225 after a proper reflow process reveals the complete wetting to the pad and the proper wetting angle of the flux residue.,Cross-section of proper Double Drop PBGA,Cross-section of

14、 PBGA 225 after Soldering,BGA Self-Alignment Effect,The self-alignment effect as the solder balls go into reflow,BGA Self-Alignment Effect Documented by Philips CFT,Source: BGA Joint Formation, Jan Kolsters, Philips CFT, Eindhoven, Netherlands, May 2000,Video clip of BGA joint formation revealing th

15、e self-alignment effect. The video was generated using the ERSASCOPE Inspection System.,Click here to begin video,BGA Repair: Hot Air Systems,BGA Repair: Hot Air vs. IR,Heat distribution across surface of BGA - convection and dark IR,Typical BGA Problems: X-ray Inspection,Deformed balls, i.e. non-sp

16、herical,Missing ball, solder bridging,Non-uniform solder quantity,Voids,Misregistration,CBGA soldered to PCB,X-ray image of CBGA after soldering,ERSASCOPE image of CBGA. Cracking zone is visible,X-ray image of PBGA 225:A and B show mistakes but are unclear of source,A. ERSASCOPE reveals flux residue

17、 bridge with conductive particles,B. ERSASCOPE shows incomplete solder melt of paste.,B,A,Typical BGA Problems: Visual Inspection and X-ray combined,Dark IR vs. light IR for PCB-reflow applications,Wavelength ranges of some radiation sources and their position in the spectrum of electromagnetic wave

18、s.,The top and bottom ERSA dark IR radiators are medium wavelength (2-8 m), which has been proven to have the optimal absorption/reflection radio between light and dark colors. The component body, substrate, and leads are safely and evenly heated, thereby reducing any risk of damage during the reflo

19、w process.,ERSA Dark IR BGA Repair: Uniform Heat Distribution,Heat distribution across surface of BGA 169,BGA Repair: Production like results with IR 500A,Source: Fraunhofer Institut ISIT, Itzehoe, Germany,Rework Equipment Purchase Decision Flow Chart,2. Repeatability - User-Friendly?,3. Flexibility

20、 - Chips, Plastic, BGA, PTH,.?,- Initial Investment? - Cycle Time? - Nozzles, etc.? - Spare Parts, e.g. heaters?,4. Return on Invest - Operational Costs ?,PL 500 A: Optical BGA / SMD Placement System,Motorized Z-axis,Zoom, and FocusSplit OpticsAuto ZoomPre-setsAuto Vac Pick-n-PlaceTwo Camera Inputs

21、/ Auto Switch Stand alone or fully integrated,BGA, CSP, Flip Chip Precision Placement and Reflow,ERSA IR 500 A International Users List,ABB ADI AGFAAIRSYS NavigationArab Britisch Dynamics Co.ASG LuftfahrttechnikBertelsmann Blaupunkt BORAQ Bosch British Aerospace Cellstar COMPAQComtech Data-Fax DIALOG Semiconductor Digitron da AmazoniaEFACEC EFORE Oy EIA-Electronica AvionicosELABO GmbH Ericsson ComponentsEricsson Radio SystemsFAST Link Fischer ElektronmechanikFraunhofer Institut Gallyas S.A.GLOBAL NETGrundig,HCL Heidelberger DruckmaschinenI.S.T.-InstitutoIBMIn