ELECTRONICS INDUSTRIES Design and Assembly …

1 IPC-7095 ADesign andAssembly ProcessImplementationfor BGAsDeveloped by the Device Manufacturers InterfaceCommittee of IPCU sers of this publication are encouraged to participate in thedevelopment of future :IPC3000 Lakeside Drive, Suite 309 SBannockburn, Illinois60015-1219 Tel 847 847 :IPC-7095 - August 2000 ASSOCIATION CONNECTINGELECTRONICS INDUSTRIES Table of .. Criteria (Determination of PackageStyle and Assembly Processes) .. Comparison .. 42 APPLICABLE .. 73 MANAGING BGA of Infrastructure .. Patterns and Circuit BoardConsiderations .. Equipment Impact .. Requirements .. Requirements .. to Market Readiness .. Step Analysis .. Limitations and Issues .. Inspection .. Sensitivity .. Unbalanced BGA Design .. in BGA .. Issues .. Concerns.

2 124 COMPONENT Packaging Comparisonsand Drivers .. Feature Comparisons .. Package Drivers .. Issues .. Handling .. Performance .. Estate .. Performance .. Mounting in the BGA Package .. Bond .. Chip .. Standards for BGA .. Pitch .. Package Outline .. Size Relationships .. Packaging Style Considerations .. Ball Contact Alloy .. Attach process .. Ball Grid Array .. Column Grid Arrays .. Ball Grid Arrays .. Die Packaging .. Folded Package Technology .. Stack Packaging .. and Stacked Packaging .. of Multiple Die Packaging .. Connectors .. Considerations forBGA Connectors .. Considerations forBGA Connectors .. Construction Materials .. of Substrate Materials .. of Substrate Materials .. Package Design Considerations.

3 And Ground Planes .. Integrity .. Spreader Incorporation Insidethe Package .. Package Acceptance Criteria andShipping Format .. Balls .. in Solder Balls .. Ball Attach Integrity .. Coplanarity .. Sensitivity (Baking, Storage,Handling, Rebaking) .. Medium (Tape and Reel,Trays, Tubes) .. 275 PCBS AND OTHER MOUNTING of Mounting Structures .. Resin Systems .. Structures .. 28 October (Multilayer, Sequentialor Build-Up) .. of Mounting Structures .. Systems .. Expansion .. Transition Temperature .. Absorption .. Finishes .. Air Solder Leveling .. Surface Protection .. Platings/Coatings .. Mask .. Vs. Dry Film Solder Masks .. Solder Masks .. Filling .. Structure Incorporation ( ,Metal Core Boards) .. Sequences.

4 Transfer Pathway .. 396 PRINTED CIRCUIT Assembly Placement and Clearances .. and Place Requirements .. Requirements .. Placement .. Legends (Silkscreen, CopperFeatures, Pin 1 Identifier) .. Sites (Land Patterns and Vias) .. Vs. Small Land and Impact on Routing .. Mask Vs. Metal Defined Land Design . Width .. Size and Location .. and Conductor Routing Strategies .. Via-in-Pad and Impact onReliability Issue .. of Wave Solder on Top Side BGAs .. Side Reflow .. of Top Side Reflow .. of Avoiding Top Side Reflow .. Side Reflow for Lead Free Boards .. and Test Point Access .. Testing .. to the Solder Balls During Testand Burn-In .. Board Testing .. Testing .. Design for Manufacturability Issues .. Design .. Product Test Coupons.

5 Management .. Interface Materials .. Sink Attachment Methods for BGAs .. Requirements .. Data Transfer .. 587 Assembly OF BGAS ON PRINTED Assembly Processes .. Paste and Its Application .. Placement Impact .. Systems for Placement .. Soldering and Profiling .. Vs. No-Clean .. Standoff .. Messaging Protocols .. Processes .. Coatings .. of Boards and Modules .. Techniques .. Usage .. Image Acquisition .. and Discussion of X-Ray SystemTerminology .. of the X-Ray Image .. Acoustic Microscopy .. Standoff Measurement .. Inspection .. Analysis Methods .. and Product Verification .. Testing .. Coverage .. Testing .. Testing .. Screening Tests .. process Control Criteria forPlastic BGAs .. 76 IPC-7095 AOctober Bridging.

6 Solder .. Correlation/ process Improvement .. Heating .. Defects .. Processes .. Philosophy .. of BGA .. Mechanisms and Failure ofSolder Attachments .. Joints and Attachment Types .. Expansion Mismatch .. Expansion Mismatch .. Expansion Mismatch .. Attachment Failure .. Attachment Failure Classification .. Signature-1: Cold Solder .. Signature-2: Land, Nonsolderable .. Signature-3: Ball Drop .. Signature-4: Missing Ball .. Signature-5: Package Warpage .. Signature-6: Mechanical Failure .. Signature-7: Insufficient Reflow .. Factors to Impact Reliability .. Technology .. Height .. Design Considerations .. of Solder Attachments ofCeramic Grid .. Free Soldering of BGAs .. (DfR) process .. and Qualification Tests.

7 Procedures .. Joint Defects .. Recommendations .. 999 DEFECT AND FAILURE ANALYSISCASE Defined BGA Conditions .. BGA Solder Ball Conditions .. Solder Paste Conditions .. Determination Through X-Ray andMicrosection .. Interposer Bow and Twist .. Joint Conditions .. Solder Condition .. Oxide .. of Dewetting .. Condition .. Solder Joint .. of Contamination .. Solder Ball .. Solder Ball .. Bridge .. Disturbed Solder .. Deformed Solder Ball .. Missing Solder Interface .. Contact .. Bridge .. Solder Reflow .. Solder .. Solder .. 10710 10811 BIBLIOGRAPHY AND 109 FiguresFigure 1-1 Area Array I/O Position Comparisons .. 2 Figure 1-2 Area Array I/O Position Patterns .. 3 Figure 1-3 Application Specific Module (ASM) BallGrid Array Format.

8 3 Figure 1-4 Conductor Width to Pitch Relationship .. 5 Figure 1-5 Plastic Ball Grid Array, Chip Wire Bonded .. 5 Figure 1-6 Ball Grid Array, Flip Chip Bonded .. 6 Figure 1-7 Conductor Routing Strategy .. 6 Figure 1-8 MCM Type 2S-L-WB .. 7 Figure 3-1 BGA Warpage .. 11 Figure 4-1 BOC BGA Construction .. 14 Figure 4-2 Top of Molded BOC Type BGA .. 14 Figure 4-3 Cross-Section of a Plastic Ball Grid Array(PBGA) Package .. 19 Figure 4-4 Cross-Section of a Ceramic Ball Grid Array(CBGA) Package .. 19 Figure 4-5 Cross-Section of a Ceramic Column GridArray (CCGA) Package .. 19 Figure 4-6 Polyimide Film Based Lead-Bond BGAP ackage Substrate Furnishes CloseCoupling Between Die Pad andBall Contact .. 20 Figure 4-7 Comparing In-Package Circuit RoutingCapability of the Single Metal LayerTape Substrate to Two Metal LayerTape Substrate.

9 20 Figure 4-8 Single Package Die-Stack BGA .. 21 October 2004 IPC-7095 AvFigure 4-9 Folded Multiple-Die BGA Package .. 21 Figure 4-10 Ball Stack Package .. 21 Figure 4-11 The Standard SO-DIMM Memory CardAssembly .. 21 Figure 4-12 Folded and Stacked Multiple Die BGAP ackage .. 22 Figure 4-13 BGA Connector .. 23 Figure 4-14 Example of Missing Balls on a BGAC omponent .. 26 Figure 4-15 Example of Voids in Eutectic Solder Balls .. 26 Figure 4-16 Examples of Solder Ball/Land SurfaceConditions .. 26 Figure 4-17 Establishing BGA Coplanarity Requirement .. 27 Figure 4-18 Ball Contact Positional Tolerance .. 28 Figure 5-1 Examples of Different Build-UpConstructions .. 29 Figure 5-2 Typical Mud Crack Appearance of BlackPad Surface .. 33 Figure 5-3A Large Region of Severe Black Pad withCorrosion Spikes Protruding into NickelRich Layer Through Phosphorus RichLayer Underneath Immersion GoldSurface.

10 33 Figure 5-4 Work and Turn Panel Layout .. 36 Figure 5-5 Distance from Tented Land Clearance .. 36 Figure 5-6 Via Plug Methods .. 38 Figure 5-7 Solder Filled and Tented Via Blow-Out .. 39 Figure 6-1 BGA Alignment Marks .. 40 Figure 6-2 Solder Lands for BGA Components .. 41 Figure 6-3 Good/Bad Solder Mask Design .. 42 Figure 6-4 Square Array .. 43 Figure 6-5 Rectangular Array .. 43 Figure 6-6 Depopulated Array .. 43 Figure 6-7 Square Array With Missing Balls .. 43 Figure 6-8 Interspersed Array .. 44 Figure 6-9 Cross Section of mm Ball with Via-in-Pad Structure (Indent to the upper leftof the ball is an artifact.) .. 44 Figure 6-10 Cross Section of Via-in-Pad DesignShowing Via Cap and Solder Ball .. 45 Figure 6-11 Via-In-Pad process Descriptions .. 45 Figure 6-12 Example of Top Side Reflow Joints.