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Micro-Usmd Rework

Micro-Usmd Rework. These are very small BGA style components. What are Micro - Usmd. These are generally Audio Amplifiers. Used on most mobile products Cell phones ,tablets, IPods Laptops Game machines Amplifier products, Stereos high quality amplifiers. Micro SMD Evolution.

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Micro-Usmd Rework

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  1. Micro-Usmd Rework These are very small BGA style components

  2. What are Micro - Usmd These are generally Audio Amplifiers • Used on most mobile products • Cell phones ,tablets, IPods • Laptops • Game machines • Amplifier products, • Stereos high quality amplifiers

  3. Micro SMD Evolution

  4. Micro –SMDs on a Penny

  5. Component views

  6. Micro-Usmd sizes .05mm (2 Mill )stand off on .5mm+.4mm pitch Controlling flux quantity is essential or component will swim. .1mm (4 mill)flux dip blocks should be used with gel flux

  7. Equipment Requirements Fine Placement Head Accuracy 0.001” (.025mm) Standard Placement Head Accuracy 0.004” (0.1mm) Camera

  8. New Micro –Usmd Specifications

  9. Reflow component back Without moving adjacent components Removal clean pads Flux new component With conduction tools or with convection(hot air)... Clean with a hoof tip or with small tip and solder wick to remove old solder. vacuum desolder tool can also be used Options flux pcb pads this not a process Flux dip part half the thickness of solder ball. what type of flux Gel flux used for POP dipping or normal lead free gel flux should be used not liquid flux Pick up parts Dip in gel flux Align component to pads Place component This is where the how to present component to vacuum pick on machine. By hand can be done not practical but slow and inexpensive. Use tape feeders to pick part from tape as supplied by component manufacturer. Place and release without moving package, using snap off or puff off that will release part in controlled repeatable method Dip Micro-USD in dip block that has been manually screen printed to give consistent flux coating to balls Camera with top to bottom view is essential for these components. Process for rework

  10. Thermal tweezers will be quick and simple if Component spacing allows this ThermalRemoval Is Easy and Safe with Metcal Tweezer. Tin removal from pads with mini-hoof tip using same solder station, MX500.

  11. Removal with convection Hot air removal and Reflow tool • Hot air nozzle with vent holes to stop pressure moving components. Used for reflow and removal with vacuum cup inside for removal

  12. Tin level must be equal for replacement Tinned pads must be leveled with a hoof solder tip or can be cleaned by using solder wick Alignment with Camera top to bottom view is essential

  13. Clean up solder wick with very fine tip 1.5mm square Micro-Usmd Tooth pick to reference size Various tips available the one shown is a SMTC 1174 Alternatively Ultra Fine are available from Metcal mx series UFTC 7CN04 (.1mm bent hoof ),UFTC7DR412( .1mm drag tip).

  14. Picking components up from tape is the best solution

  15. Micro_SMD Flux dip process is required. If excessive flux is brushed onto PCB it may cause the part to float off the pads. Pick up package from tape in tape feeder. Manual handling is that easy.

  16. Placing parts onto small pick up tube for small volume. Close up of vacuum cup and reflow nozzle

  17. Micro_SMD Pin 1 location Pin 1 location indicator

  18. NEVER Liquid Flux √☺

  19. Flux dip Micro-Usmd components Component pitch .5mm pitch and .4 mm can use 4 and 3 mill dip blocks solder ball size is 8-6 mills.

  20. Flux Dip with Gel Flux Dip half the thickness of solder ball height

  21. Flux Dip with Gel Flux

  22. Flux transfer complete, placement to PCB is next Flux Dip with Gel Flux Flux Deposition On Bottom 1/3 Of Solder Ball

  23. Flux Dip with Gel Flux is good for BGA components as well 4 mil dip Block(.1mm) Gel Flux removed is uniform

  24. Alignment and placement • Placement height is important to touch PCB so gel flux holds part to pads. • Gel flux is used to be active during reflow process liquid flux would dry up • Release time needs to be controlled we call it puff off time

  25. Component Alignment

  26. Alternative to flux dip is Paste dip This is a .2mm ball dipped in .1mm type 6 paste Indium 96.5Sn 3.0Ag 0.5Cu Ind256 flux 688-52-2 same tools used as used for flux gel

  27. Reflow Profile for Lead VS Lead-Free Ramp down in PB Temperature ramp up in PB is slower Key Ramp Rate in cooling Flux activation time / area

  28. Dual Preheater Software Profile

  29. Convection Reflow Profile

  30. X-Ray Inspection 8 ball x ray, if any ball is 25% smaller this is generally considered the maximum difference in size which is acceptable .This may vary from which type of x ray machine is used. 8 ball x ray which shows all joints are the same size

  31. References • National semiconductor now TI Texas instruments for some technical specifications and photos • Indium for materials supply of POP materials Mario Scalzo Mscalzo@indium.com • For more details contact Paul wood ok international pwood@okineternational.com

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