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Placement of Advanced SMT Devices

Placement of Advanced SMT Devices. Topics to be covered. Evolution of surface mount component technology Ball Grid Arrays (BGA) Chip Scale Packages (CSP) Assembly process considerations One definition: I/O = Input/Output (one connection point of an electronic component - lead or ball).

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Placement of Advanced SMT Devices

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  1. Placement of Advanced SMT Devices

  2. Topics to be covered • Evolution of surface mount component technology • Ball Grid Arrays (BGA) • Chip Scale Packages (CSP) • Assembly process considerations • One definition: • I/O = Input/Output (one connection point of an electronic component - lead or ball)

  3. Evolution of Componentry Fine Pitch (< 0,625 mm) Area Arrays - Fine Pitch (CSP, flip chip) Discrete Passives Ultra Fine Pitch (< 0,5 mm) Through-hole Components Surface Mount Components TAB Area Arrays - Course Pitch (BGA) Standard SMDs - SOT - SOIC - PLCC COB 1960 1980 1990 2000

  4. Products Requiring Speed & I/O

  5. 1,000 Bare Die (CSP, flip chip) 800 PGA BGA 600 Package Pin Count TAB 400 SMT 200 0 10 50 100 200 300 500 Clock Frequency, MHz Speed and I/O Driving Packaging Source: Semiconductor World, May 1996

  6. Ball Grid Arrays 255 pin CBGA 480 pin TBGA

  7. Ball Grid Arrays • Many varieties exist • plastic, ceramic, metal • 1,27 and 1,0 mm pitch most common • Greatest advantages are • ability to use existing SMT infrastructure • superior electrical performance • ability to use high I/O die without driving up the cost of the motherboard

  8. Ball Grid Arrays • Soldering of BGA’s is a robust process • Inspection and repair are difficult but typically are not required once process windows are determined • Some component reliability concerns still exist • pop-corning • TCE mismatch (CBGAs)

  9. Chip Scale Packages

  10. Chip Scale Packages • CSPs are still in their infancy • Abundance of new designs and form factors (at least 50 different types currently defined) • Accepted standard package definition • no more than 1.2x the size of the die itself • supports both perimeter and array escape of I/O

  11. Chip Scale Packages • CSPs are seen as an alternative to flip chip with perceived benefits of • standard pad layouts • test and burn-in compatibility • does not require underfill (in theory)

  12. Chip Scale Packages • Primary application areas • memory (especially flash - Intel and T.I.) • control (A/D, low I/O logic, microcontrollers) • digital processing (DSPs, microprocessors, ASICs) • Wide spread usage is growing rapidly

  13. Shrinking memory packages

  14. A Popular CSP Format

  15. X-Ray Soldering Defect Detection Shorts • Tessera µBGA • with 46 Solder Joints: • Two shorts • Automatic detection

  16. X-Ray Soldering Defect Detection Missing Solder Joints • Tessera µBGA, • 22 out of 46 Solder Joints: • Two missing solder joints • Automatic detection

  17. X-Ray Soldering Defect Detection Misregistration • CSP with 9 Solder Joints: • Misregistration of the CSP (one pad in both directions) • Automatic detection 

  18. X-Ray Soldering Defect Detection Pores or Voids • BGA352, 16 Solder Joints: • Medium voiding • Automatic detection 

  19. X-Ray Soldering Defect Detection Insufficient solder • Tessera µBGA, 6 out of 46 Solder Joints: • OVHM (Oblique View) • Solder joints 2, 3, 4 open • Solder joints 1, 5 ok • Solder joint 6 not well soldered 1 2 3

  20. X-Ray Soldering Defect Detection 3-D Image Reconstruction • Tessera µBGA, 6 out of 46 Solder Joints: • 3D image for better visualisation

  21. X-Ray Soldering Defect Detection 3-D Image Reconstruction • Tessera µBGA, 6 out of 46 Solder Joints: • 3D image for better visualisation

  22. Component Placement Issues • Component Feeding • Component Handling • Centering and Inspection • Placement Accuracy

  23. Component Feeding • Matrix tray format (JEDEC or waffel pack) • tray inside of placement machine • XY system must have enough travel to let each nozzel access each tray pocket • components fed from external tray feeder • handling system between tray feeder and placement machine must not rely on vacuum under the component • Tape format • usually no special issues

  24. Component Handling • BGAs • usually no issues (except possibly overall package size) • CSPs • often have exposed die which require gentle handling (especially if circuit-side-up) • programmable pick/placement forces • possibly even special die nozzles • be careful if placing with conventional • turret-style chipshooter machines!

  25. Component Centering • Component perimeter centering • Laser alignment • Vision alignment • back illumination • Ball/feature centering • Vision alignment • front illumination Fastest * Most accurate * requires high quality components with a consistent relationship between perimeter and position of balls

  26. Juki‘s Multi-Nozzle Laser Alignement

  27. Juki‘s Illumination System Backlighting system Frontlighting system

  28. 470nm 660nm Component Illumination, front • To combat confusing reflections: • Adjustable light source • front or back lighting • multiple wavelengths of front lighting • Adjustable angle of illumination ADJUST POSITION FOR BEST LIGHTING ANGLE

  29. Image Processing • Important features • “All Ball” recognition • Ball presence/absence check • Ball diameter check • Ball coplanarity check • Random ball pattern programming

  30. Placement Accuracy • Required accuracy depends on • Pitch and ball diameter of component • Pad diameter on the board • Quality and consistency of board • Process tolerance for misalignment “Accuracy is in the eye of the beholder.”

  31. Placement Accuracy • „Typical“ accuracy requirements (3s) • discrete SMT, BGA1 +/- 150 mm • leaded SMT , BGA2 +/- 100 mm • fine pitch SMT , CSP3 +/- 75 mm • low I/O flip chip +/- 40 mm Notes: 1 1,27 mm pitch 2 0,75 mm pitch 3 0,5 mm pitch

  32. 11,000 CPH practical throughput* 80 Feeders Multi-nozzle laser head with 4 nozzles Places 0201-20mm2 ICs KE-2020 KE-2010 2000 Series High Speed Flexible Chip Shooters • 11,000 CPH practical throughput* • 1,800 CPH practical throughput, fine pitch* • 80 Feeders • Multi-nozzle laser head with 1 fine pitch head • Places 0201-50mm2ICs, QFPs, BGAs, CSPs *All placement rates are in accordance with emerging IPC Standard 9850.

  33. 13,200 CPH throughput 80 Feeders Multi-nozzle laser head with 4 nozzles Places 0201-20x20mm IC’s KE-2050 KE-2060 FX - 1 New Modules • 12,500 CPH throughput 3,300 CPH fine pitch* • 80 Feeders • Multi-nozzle laser head + 1 fine pitch head • Places 0201-75x75mm ICs, QFPs, BGAs, CSPs • 25,000 CPH throughput (IPC 9850) • 80 Feeders • 2 Multi-nozzle laser head with 4 nozzles • Places 0201-20x20mm IC’s * With Multi-Nozzle-Vision-Centering.

  34. Juki Production Solutions

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