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

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Component Issues – LGA & QFN Potential Potential Issues: Issues: – Land Pattern Design • Pad Size Uniformity (SMD vs NSMD) – Paste Volume Control • Pad to Pad Volume • Pad to Design Defined Volume – Component/PCB Flatness • Internal Split Plane • NFP Removal Impacts – Component/PCB Warpage – Decrease Component Stand<strong>of</strong>f Height • Decreased Reliability
% PAD SIZE INCREASE 60 50 40 30 20 10 Trace Routing Impacts Solder Joint 0 EFFECTIVE PAD SIZE ANALYSIS 4 10 15 20 WIDTH OF TRACE 10 Mil Nom 15 Mil Nom 20 Mil Nom 10 Mil Max 15 Mil Max 20 Mil Max Increased Increased Mounting Mounting Pad Pad Size Size Affected Affected By: By: • Number Of Trace Connections To Each Pad • Width Of Trace Connections To Each Pad • Size <strong>of</strong> Pad – Small Pads Have Less Margin • Uniformity Of Trace Egress Direction – Some Package Types Are More Sensitive Than Others • Uniformity Of Trace Sizes
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 and 8: Component Issues - Decreasing Pitch
Page 9: LGA Pad Design Solder Solder Mask M
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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