Root Cause Failure Analysis of Printed Circuit Board ... - SMTA

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LGA/QFN Package Assembly • Trace Routing Under Component Create Localized Height Variations – Stand<strong>of</strong>f Height Variation • Leadless Devices Are More Sensitive To PCB/Component Flatness/Warpage – Received Condition – In-process Condition (During Reflow/Rework Solder Process) LGA Package BGA Package
LGA Pad Design Solder Solder Mask Mask Defined Defined Non Non-Solder Non Solder Solder Mask Mask Defined Defined • Solder Solder Solder wicking wicking wicking around around around around NSMD NSMD pads pads produce produce significantly significantly lower lower molten molten solder solder height. height. • Solder Solder Solder mask mask defined defined defined pads pads should should be be used used for for LGA LGA and and 0.4mm 0.4mm & & smaller smaller pitch pitch pitch BGA/CSP BGA/CSP BGA/CSP packages. packages. packages.
Page 1 and 2: Root Root Root Cause Cause Failure
Page 3 and 4: Today’s Electronic Designs • Co
Page 5 and 6: Component Issues - Warpage • High
Page 7: Component Issues - Decreasing Pitch
Page 11 and 12: % PAD SIZE INCREASE 60 50 40 30 20
Page 13 and 14: Component Pad - Thermal Imbalance
Page 15 and 16: Thick Copper Design A A CTE CTE Mis
Page 17 and 18: Thick Copper Design Lack Lack Of Of
Page 19 and 20: Copper Etch Process • H H = = = H
Page 21 and 22: Pad Size Reduction Current Procedur
Page 23 and 24: • Voids in Solder Joints - Unfill
Page 25 and 26: Stencil Tolerances Artwork Artwork
Page 27 and 28: Offset Paste - Normal Placement Pho
Page 29 and 30: Match Placement To Paste • Slight
Page 31 and 32: Solder Paste Printing Volume Air Bu
Page 33 and 34: Internal PCB Impacts Number Of Laye
Page 35 and 36: Wave Solder & Rework Issues 0.005
Page 37 and 38: PCB Finish Vs Solder Spread - OSP -
Page 39 and 40: Defects Caused By Improper Thermal
Page 41 and 42: Through Hole Pad Design • Square
Page 43 and 44: Effect of Board Thickness On Topsid
Page 45 and 46: Solder Mask Selection Matte Finish
Page 47 and 48: Cleaning Chemistry Compatibility
Page 49 and 50: Inspectability - AOI, AXI, HVI •
Page 51 and 52: Cracked Cap Issue • PCA Is Assemb
Page 53 and 54: Source Of Contamination What is Sou
Page 55 and 56: DFX Software Flexibility • Concur
Page 57 and 58: DFX PCA-PCB Software Systems Mentor
Page 59 and 60:
DFX Mechanical Software Systems Ana
Page 61 and 62:
Closing Thought “We can’t solve
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Root Cause Failure Analysis of Printed Circuit Board ... - SMTA

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