Increase Test Coverage Higher Density – Large Boards Copyright © 2011, Circuit Check, Inc. What's Involved? Control – UUT has an ICT friendly design – Increase your odds in the manufacturing process • Don't fight the board – Let the board select the fixture 2 Smaller Targets Copyright © 2011, Circuit Check, Inc. Copyright© 2011 Circuit Check, Inc. Design ICT Friendly UUT • Even distribution of test pads • Tooling holes P0.125 on a diagonal, non plated • Filled/Plugged vias: Plan on probing only Type VII Filled and Capped vias • Agilent Bead Probes avoid manufacturing issues and place at 0.075" centers • Probing gold-plated fingers may cause blemishes from probes – Check company quality acceptance practices – Add test point location • Test pads located 0.0625 away from edge of board, and or 0.125 away from edge of rails. • Test pad minimum spacing from component edge to test pad center 0.018" plus half solder pad width per IPC-9850 placement guideline. 3 Smaller Targets Copyright © 2011, Circuit Check, Inc. Copyright© 2011 Circuit Check, Inc. Test Pad Location to Component Half the solder pad width plus ► probe clearance equals total test pad clearance required. Half the solder pad width plus ► probe clearance equals total test pad clearance required. 4 Smaller Targets Copyright © 2011, Circuit Check, Inc. X75 X50 X39 X31 .038 .0312 .0264 .024 X75 X50 X39 X31 .080 .073 .0684 .0654 X75 X50 X39 X31 X75 X50 X39 X31 Copyright© 2011 Circuit Check, Inc. .080 .073 .0684 .0654 .110 .103 .0984 .0954 Probe Spacing Choices Are here to stay! X-Probe Technology .100 - .075 Spacing Standard Technology .039 .050 .075 .100 Spacing Spacing Spacing Spacing 100 mil probe Probe Probe Plate Spacer Plate Termination Plate Termination 5 Copyright © 2011, Circuit Check, Inc. Copyright© 2011 Circuit Check, Inc. .050 .039 .030 Spacing Spacing Spacing 75 mil probe 50 mil probe 39 mil probe Test Pad MINIMUM Spacing Relative to Each other Minimum Recommended Probe / Receptacle Spacing 100-Mil Probe 100-Mil Probe 75-Mil Probe 50-Mil Probe 75-Mil Probe 50-Mil Probe .068” .048” .039” 31-Mil Probe 6 Copyright © 2011, Circuit Check, Inc. 31-Mil X-Probe .085” 39-Mil Probe Smaller Targets 39-Mil Probe .030" Copyright© 2011 Circuit Check, Inc. Increase Your Odds PCB Manufacturing • Solder mask clearance from edge of pad P .2mm • Filled/Plugged vias: Plan on probing only IPC 4761 Type VII Filled and Capped vias • Copper plated vias and pads can be more difficult due to oxidation and OSP – other plating options to consider: • ENIG, • Immersion Ag or Sn, • SAC (SnAgCu) • Keep lead lengths to 0.050" for 100 – 75 mil probes – Probing leads with < 75mil probes is not recommended • Agilent Bead probes – correct stencil aperture and orientation 7 Smaller Targets Copyright © 2011, Circuit Check, Inc. Copyright© 2011 Circuit Check, Inc. The Board Selects… UUT Characteristics selects the fixture • • • • • • • • Smallest test pad size Probe spacing Probe count Board size Test points both sides Test access through connectors Switching power supplies & regulators Thermal loading during test 8 Smaller Targets Copyright © 2011, Circuit Check, Inc. Copyright© 2011 Circuit Check, Inc. Vacuum 0.18"/.016" 0.030" 9,100 19.5 x 21.0 Both 3 sides Yes No No y 18 watts @ 90°c 9 Smaller Targets Copyright © 2011, Circuit Check, Inc. vs. • • • • • • • • • • Pneumatic Smallest test pad size Probe spacing Probe count Max UUT size Single or dual sided Side access Bi-Level Tri-Level Quad-Level Component Cooling Copyright© 2011 Circuit Check, Inc. 0.16"/.016" 0.025" 20,000 28 x 39.5 Both 4 sides Yes Yes Yes y 35 watts @ 90°c Smaller Test pads w/Guided Probe 0.016" Test Pad rds 0.035 Test Pad Probe contacting inner 2/3 of test pad. Probe contacting edge of test pad. Top plate "funnel" drilled slightly larger than probe shaft. Probe/Socket tilted in mounting hole, UUT pushed to maximum tolerance extreme. Probe/Socket tilted in mounting hole, UUT pushed to maximum tolerance extreme. Receptacle mounting and fit are less of a concern when probes are guided . 10 Smaller Targets Copyright © 2011, Circuit Check, Inc. Copyright© 2011 Circuit Check, Inc. Guide Plate Options “Guide Plate" added for Top Side probing 11 Smaller Targets Copyright © 2011, Circuit Check, Inc. "Quick Plate " is cut out of the Top Plate ® Copyright© 2011 Circuit Check, Inc. Stretching the 307x Boundaries • Not enough probable area on the large 307x fixture? • Long wire kit not really an option? • Custom solutions to expensive or turn time too long? 12 Copyright © 2011, Circuit Check, Inc. Extended Probing Kit limits Large usable area: 19.5" front to back 21.032" left to right Mandatory keep out areas for pull down Towers. Transfer probe area if required may reduce available UUT size if Movement to side is not possible. Vacuum port locations will change to accommodate the UUT positioning Copyright © 2011, Circuit Check, Inc. Extended Probe Field Normal .250 stroke probes in the 307x rail area and beyond. Copyright © 2011, Circuit Check, Inc. Oversize Wireless Options Near Standard Design Vacuum or Pneumatic • Maximum Size UUT without increased T-Board Cost – Maximum probe-able UUT size 19.5" front to back and 21" left to right. • Transfer pins from top access and side access units may affect maximum size. • Keep out areas associated with tester's pull downs Custom Wireless Design Pneumatic only • Maximum UUT size without keep out areas – When money is not a consideration 28.0" x 39.5" • Lead time based on complexity Copyright © 2011, Circuit Check, Inc. Summary • PCB - design optimized for ICT test. • Manufacturing - considerations to increase first pass yield and reduce NDFs. • Increase Test Coverage: – Decreased probe spacing 0.8 & 1.0mm – Smaller test targets • UUT - matched to fixture capabilities • Extended probing up to 19.5" x 21.0" 16 Smaller Targets Copyright © 2011, Circuit Check, Inc. Copyright© 2011 Circuit Check, Inc. Questions? 17 Copyright © 2011, Circuit Check, Inc. Copyright© 2011 Circuit Check, Inc.