Printed Circuits Handbook, Seventh Edition

Clyde F. Coombs, Jr, (Los Altos, CA) recently retired from Hewlett-Packard. He is the editor of all five editions of the Printed Circuits Handbook, the first of which was published in 1967. He is also the editor of two editions of the Electronics Instrument Handbook and the communications Network Test and Measurement Handbook.

Part 1: Printed Circuit Technology Drivers

Chapter 1. Electronic Packaging and High-Density Interconnectivity Clyde F. Coombs, Jr., and Happy T. Holden 3
1.1 Introduction / 3
1.2 Measuring the Interconnectivity Revolution / 3
1.3 Hierarchy of Interconnections / 6
1.4 Factors Affecting Selection of Interconnections / 7
1.5 ICs and Packages / 9
1.6 Density Evaluations / 10
1.7 Methods to Increase PWB Density / 13
1.8 References / 18

Chapter 2. Types of Printed Wiring Boards Hayao Nakahara 19
2.1 Introduction / 19
2.2 Classification of Printed Wiring Boards / 19
2.3 Organic and Nonorganic Substrates / 21
2.4 Graphical and Discrete-Wire Boards / 21
2.5 Rigid and Flexible Boards / 22
2.6 Graphically Produced Boards / 22
2.7 Molded Interconnection Devices / 27
2.8 Plated-Through-Hole Technologies / 27
2.9 Summary / 30
2.10 References / 30

Part 2: Managing the Printed Circuit Supply Chain

Chapter 3. Basics of Printed Circuit Supply Chain Management Tim Rodgers 33
3.1 Introduction / 33
3.2 General Business Considerations / 34
3.3 Contract Manufacturers / 35
3.4 Criteria for Evaluating Suppliers / 35
3.5 Supplier Selection Criteria Example / 41

Chapter 4. Design for Manufacturability Tim Rodgers 43
4.1 General Principles / 43
4.2 PCB/PCA Pricing Models / 44
4.3 Process Cost Drivers / 49
4.4 Production Yield and Design for Manufacturability / 51
4.5 DFM Complexity Models / 59

Chapter 5. Manufacturing Information, Documentation, Formatting, and Exchange Happy T. Holden 63
5.1 Introduction / 63
5.2 Manufacturing Information / 64
5.3 Fabrication Information Exchange / 68
5.4 Data Exchange Formats / 73
5.5 Initial Design Review / 86
5.6 Design Input / 94
5.7 Design Analysis and Review / 99
5.8 Acknowledgments / 99
5.9 References / 100

Chapter 6. Supplier Selection and Qualification Tim Rodgers 101
6.1 Introduction / 101
6.2 Evaluating Suppliers / 102
6.3 Supplier Selection / 113
6.4 Supplier Qualification / 114

Chapter 7. Process Control, Monitoring, and Incoming Inspection Tim Rodgers 117
7.1 Introduction / 117
7.2 Process Capability and Process Control / 117
7.3 Process Monitoring and Troubleshooting / 122
7.4 Assessing a PCB Fabricators Capability / 122
7.5 Testing and Inspection / 156
7.6 Incoming Inspection / 158

Chapter 8. Product Acceptance and Feedback Tim Rodgers 159
8.1 Introduction / 159
8.2 Design Qualification / 159
8.3 Incoming Inspection and Lot Acceptance / 160
8.4 Supplier Performance Management / 162
8.5 Business Reviews / 165
8.6 Strategic Supplier Management / 167

Part 3: Materials

Chapter 9. Introduction to Base Materials Edward Kelley and Douglas Trobough 171
9.1 Introduction / 171
9.2 Grades and Specifications / 171
9.3 Properties Used to Classify Base Materials / 178
9.4 Types of FR-4 / 184
9.5 Laminate Identification Scheme / 185
9.6 Prepreg Identification Scheme / 186
9.7 Laminate and Prepreg Manufacturing Processes / 189
9.8 References / 195

Chapter 10. Base Material Components Edward Kelley and Douglas Trobough 197
10.1 Introduction / 197
10.2 Other Resin Systems / 201
10.3 Legislative Issues / 203
10.4 Additives / 207
10.5 Reinforcements / 209
10.6 Conductive Materials / 217
10.7 References / 224

Chapter 11. Properties of Base Materials Edward Kelley and Douglas Trobough 225
11.1 Introduction / 225
11.2 Thermal, Physical, and Mechanical Properties / 225
11.3 Electrical Properties / 236
11.4 Other Test Methods / 240
11.5 References / 240

Chapter 12. Base Material Performance in PCBs Edward Kelley and Douglas Trobough 241
12.1 Introduction / 241
12.2 Methods of Increasing Circuit Density / 241
12.3 Copper Foil / 242
12.4 Laminate Constructions / 247
12.5 Prepreg Options and Yield-per-Ply Values / 248
12.6 Dimensional Stability / 249
12.7 High-Density Interconnect/Microvia Materials / 250
12.8 Conductive Anodic Filament Growth / 252
12.9 Electrical Performance / 258
12.10 Electrical Performance of Lower Dk/Df Lead-Free Compatible Materials / 268
12.11 Resin and Glass Micro-Dk Effects / 268
12.12 References / 272

Chapter 13. The Impact of Lead-Free Assembly on Base Materials Edward Kelley and Douglas Trobough 273
13.1 Introduction / 273
13.2 RoHS Basics / 273
13.3 Base Material Compatibility Issues / 274
13.4 The Impact of Lead-Free Assembly on Base Material Components / 276
13.5 Critical Base Material Properties / 276
13.6 Impact on Printed Circuit Reliability and Material Selection / 288
13.7 Summary / 292
13.8 Further Reading / 292

Chapter 14. Selecting Base Materials Edward Kelley and Douglas Trobough 293
14.1 Introduction / 293
14.2 Selecting Materials for Thermal Reliability / 293
14.3 Selecting a Base Material for Thermal Reliability / 298
14.4 Selecting Materials for Electrical Performance / 304
14.5 CAF Resistance / 309
14.6 References / 315

Chapter 15. Laminate Qualification and Testing Michael Roesch and Sylvia Ehrler 317
15.1 Introduction / 317
15.2 Industry Standards / 318
15.3 Laminate Test Strategy / 319
15.4 Initial Tests / 321
15.5 Full Material Characterization / 324
15.6 Characterization Test Plan / 335
15.7 Manufacturability in the Shop / 337

Part 4: Engineering and Design

Chapter 16. Planning for Design, Fabrication, and Assembly Happy T. Holden 341
16.1 Introduction / 341
16.2 General Considerations / 342
16.3 New Product Design / 343
16.4 Specification: Capture of System Description / 346
16.5 Layout Trade-Off Planning / 349
16.6 PWB Fabrication Trade-Off Planning / 355
16.7 Assembly Trade-Off Planning / 362
16.8 References / 364

Chapter 17. Physical Characteristics of the PCB Lee W. Ritchey 365
17.1 Introduction / 365
17.2 Types of PCBs or Substrates / 366
17.3 Methods of Attaching Components / 369
17.4 Component Package Types / 369
17.5 Materials Choices / 371
17.6 Fabrication Methods / 372

Chapter 18. Electronic Design Automation and Printed Circuit Design Tools Andy Shaughnessy 373
18.1 Description of PCB Design Tools / 373
18.2 Using PCB Design Tools / 374
18.3 Major PCB Design Tools / 376
18.4 Lower-Cost PCB Design Tools / 378
18.5 Free PCB Design Tools / 379
18.6 Signal Integrity and EMC Tools / 381
18.7 Key Questions to Consider / 383
18.8 Further Reading / 383

Chapter 19. The PCB Design Process Lee W. Ritchey 385
19.1 Introduction / 385
19.2 The Virtual Prototyping Process / 387
19.3 Making the Conversion from Hardware Prototyping to Virtual Prototyping / 394

Chapter 20. Electrical and Mechanical Design Parameters Bill Hargin and Mark I. Montrose 395
20.1 Electrical and Mechanical Design Parameters Overview / 395
20.2 Introduction to Digital Signal Integrity / 396
20.3 Which Nets to Terminate and What Type of Termination to Use / 406
20.4 Introduction to Differential Signaling / 415
20.5 Introduction to Power Integrity / 419
20.6 Introduction to Electromagnetic Compatibility / 426
20.7 Introduction to Mechanical Design Requirements / 434
20.8 Types of Edge Mounting for Circuit Boards / 438
20.9 Acknowledgments / 441
20.10 References / 441

Chapter 21. The Basics of Printed Circuit Board Design Susy Webb 443
21.1 Software Selection / 443
21.2 Standards / 443
21.3 The Schematic / 445
21.4 Parts / 446
21.5 Padstacks / 448
21.6 Starting a New Board / 449
21.7 Placement / 453
21.8 Planes / 456
21.9 Stackup / 457
21.10 Routing / 458
21.11 Finishing / 464
21.12 Saving / 466
21.13 Conclusion / 466

Chapter 22. Current Carrying Capacity in Printed Circuits Mike Jouppi 469
22.1 Introduction / 469
22.2 Conductor (Trace) Sizing Charts / 470
22.3 Baseline Charts / 473
22.4 Summary / 480
22.5 References / 480

Chapter 23. PCB Design for Thermal Performance Mike Jouppi 481
23.1 Introduction / 481
23.2 The PCB as a Heat Sink Soldered to the Component / 482
23.3 Optimizing the PCB for Thermal Performance / 482
23.4 Conducting Heat to the Chassis / 490
23.5 PCB Requirements for High-Power Heat Sink Attach / 492
23.6 Modeling the Thermal Performance of the PCB / 493
23.7 Heat Sources / 496
23.8 Acknowledgment / 497
23.9 References / 497

Chapter 24. Embedded Components Vern Solberg 499
24.1 Introduction / 499
24.2 Definitions and Example / 499
24.3 Applications and Trade-Offs / 500
24.4 Designing for Embedded Component Applications / 501
24.5 Materials / 505
24.6 Material Supply Types / 509
24.7 Conclusion / 515
24.8 Acknowledgment / 515

Part: 5 High-Density Interconnection

Chapter 25. Introduction to High-Density Interconnection Technology Happy T. Holden 519
25.1 Introduction / 519
25.2 Definit
ions / 519
25.3 HDI Structures / 523
25.4 Design / 527
25.5 Dielectric Materials and Coating Methods / 529
25.6 HDI Manufacturing Processes / 541
25.7 Appendix / 549
25.8 References / 550
25.9 Further Reading / 550

Chapter 26. Advanced High-Density Interconnection Technologies Happy T. Holden 551
26.1 Introduction / 551
26.2 Definitions of HDI Process Factors / 551
26.3 HDI Fabrication Processes / 553
26.4 Next-Generation HDI Processes / 572
26.5 References / 578
26.6 Further Reading / 579

Part 6: Fabrication

Chapter 27. CAM Tooling for Fab and Assembly Happy T. Holden 583

27.1 Introduction / 583
27.2 Manufacturing Information / 583
27.3 Design Analysis and Review / 585
27.4 The CAM-Tooling Process / 586
27.5 Additional Processes / 597
27.6 Acknowledgments / 600

Chapter 28. Drilling Processes Matthias Stickel 601
28.1 Introduction / 601
28.2 Materials / 602
28.3 Machines / 608
28.4 Methods / 612
28.5 Hole Quality / 618
28.6 Troubleshooting / 619
28.7 Postdrilling Inspection / 621
28.8 Drilling Cost per Hole / 621
28.9 Acknowledgment / 624

Chapter 29. Precision Interconnect and Laser Drilling Matthias Stickel 625
29.1 Introduction / 625
29.2 Factors Affecting High-Density Drilling / 625
29.3 Laser versus Mechanical / 626
29.4 Factors Affecting High-Density Mechanical Drilling / 629
29.5 Depth-Controlled Drilling Methods / 633
29.6 Controlled Depth Via Drilling / 633
29.7 Innerlayer Registration of Multilayer Boards / 637
29.8 Laser Drilling / 637
29.9 Laser Via Formation / 639
29.10 Laser Tool Types / 639
29.11 Acknowledgment / 640
29.12 Further Reading / 640

Chapter 30. Imaging and Automated Optical Inspection Gareth Parry 641
30.1 Introduction / 641
30.2 Photosensitive Materials / 641
30.3 Dry-Film Resists / 644
30.4 Liquid Photoresists / 646
30.5 Electrophoretic Depositable Photoresists / 647
30.6 Resist Processing / 648
30.7 Design for Manufacturing / 665
30.8 Inkjet Imaging / 667
30.9 Automatic Optical Inspection / 668
30.10 References / 668

Chapter 31. Multilayer Materials and Processing C. D. (Don) Dupriest and Happy T. Holden 671
31.1 Introduction / 671
31.2 Multilayer Construction Types / 672
31.3 ML-PWB Processing and Flows / 690
31.4 Lamination Process / 697
31.5 Lamination Process Control and Troubleshooting / 704
31.6 Lamination Overview / 706
31.7 ML-PWB Summary / 707
31.8 Acknowledgment / 708
31.9 Further Reading / 708

Chapter 32. Preparing Boards for Plating Michael Carano 709
32.1 Introduction / 709
32.2 Process Decisions / 709
32.3 Process Feedwater / 711
32.4 Multilayer PTH Preprocessing / 713
32.5 Electroless Copper / 717
32.6 Acknowledgments / 719
32.7 References / 719

Chapter 33. Electroplating George Milad 721
33.1 Introduction / 721
33.2 Electroplating Basics / 721
33.3 Acid Copper Electroplating / 722
33.4 Tin Electroplating / 735
33.5 Nickel Electroplating / 736
33.6 Gold Electroplate / 739
Chapter 34. Direct Plating Hayao Nakahara 743
34.1 Direct Metallization Technology / 743
34.2 References / 753

Chapter 35. Printed Circuit Board Surface Finishes George Milad 755
35.1 Introduction / 755
35.2 PWB Surface Finishes / 757
35.3 Hot Air Solder Level / 758
35.4 Electroless Nickel Immersion Gold / 758
35.5 Nickel Palladium Gold / 761
35.6 Organic Solderability Preservatives / 763
35.7 Immersion Silver / 765
35.8 Immersion Tin / 766
35.9 Other Surface Finishes / 767

Chapter 36. Solder Mask David A. Vaughan 771
36.1 Introduction / 771
36.2 Trends and Challenges for Solder Mask / 772
36.3 Types of Solder Mask / 773
36.4 Solder Mask Selection / 774
36.5 Solder Mask Application and Processing / 778
36.6 Via Protection / 785
36.7 Solder Mask Final Properties / 786
36.8 Legend and Marking (Nomenclature) / 787

Chapter 37. Etching Process and Technologies Gareth Parry 789
37.1 Introduction / 789
37.2 General Etching Considerations and Procedures / 790
37.3 Resist Removal / 792
37.4 Etching Solutions / 793
37.5 Other Materials for Board Construction / 804
37.6 Metals Other than Copper / 805
37.7 Basics of Etched Line Formation / 806
37.8 Equipment and Techniques / 811
37.9 Acknowledgment / 814
37.10 References / 814

Chapter 38. Routing and V-Scoring Matthias Stickel 817
38.1 Introduction / 817
38.2 The Routing Operation / 817
38.3 Materials / 821
38.4 Machines / 822
38.5 Routers / 824
38.6 Parameters / 825
38.7 Depth Controlled Routing / 827
38.8 V-Scoring / 828
38.9 References / 831

Part 7: Bare Board Test

Chapter 39. Bare Board Test Objectives and Definitions David J. Wilkie 835
39.1 Introduction / 835
39.2 The Impact of HDI / 835
39.3 Why Test? / 836
39.4 Circuit Board Faults / 838

Chapter 40. Bare Board Test Methods David J. Wilkie 841
40.1 Introduction / 841
40.2 Nonelectrical Testing Methods / 841
40.3 Basic Electrical Testing Methods / 842
40.4 Specialized Electrical Testing Methods / 848
40.5 Data and Fixture Preparation / 851
40.6 Combined Testing Methods / 857

Chapter 41. Bare Board Test Equipment David J. Wilkie 859
41.1 Introduction / 859
41.2 System Alternatives / 859
41.3 Universal Grid Systems / 861
41.4 Flying-Probe/Moving-Probe Test Systems / 872
41.5 Verification and Repair / 876
41.6 Test Department Planning and Management / 876

Chapter 42. HDI Bare Board Special Testing Methods David J. Wilkie 879
42.1 Introduction / 879
42.2 Fine-Pitch Tilt-Pin Fixtures / 880
42.3 Bending Beam Fixtures / 880
42.4 Flying Probe / 881
42.5 Coupled Plate / 881
42.6 Shorting Plate / 881
42.7 Conductive Rubber Fixtures / 882
42.8 Optical Inspection / 882
42.9 Noncontact Test Methods / 882
42.10 Combinational Test Methods / 884

Part 8: Assembly, Soldering Materials, and Processes

Chapter 43. Assembly Processes Happy T. Holden 887
43.1 Introduction / 887
43.2 Through-Hole Technology / 889
43.3 Surface-Mount Technology / 899
43.4 Odd-Form Component Assembly / 923
43.5 Process Equipment Selection / 930
43.6 Conformal Coating, Encapsulation, and Underfill Materials / 933
43.7 Acknowledgments / 934

Chapter 44. Conformal Coating Jason Keeping 935
44.1 Introduction / 935
44.2 Types of Conformal Coatings / 936
44.3 Product Preparation / 940
44.4 Application Processes / 946
44.5 Cure, Inspection, and Demasking / 949
44.6 Repair Methods / 951
44.7 Design for Conformal Coating / 952
44.8 References / 955

Chapter 45. Fluxes and Cleaning Gregory C. Munie and Laura J. Turbini 957
45.1 Introduction / 957
45.2 Assembly Process / 958
45.3 Surface Finishes / 959
45.4 Soldering Flux / 960
45.5 Flux Form versus Soldering Process / 961
45.6 Rosin Flux / 962
45.7 Water-Soluble Flux / 963
45.8 Low Solids Flux / 964
45.9 Cleaning Issues / 965
45.10 Summary / 967
45.11 References / 967

Chapter 46. Soldering Fundamentals Gary M. Freedman 969
46.1 Introduction / 969
46.2 Elements of a Solder Joint / 970
46.3 Solder Overview / 971
46.4 Soldering Basics / 971
46.5 References / 975

Chapter 47. Soldering Materials and Metallurgy Gary M. Freedman 977
47.1 Introduction / 977
47.2 Solders / 978
47.3 Solder Alloys and Corrosion / 980
47.4 Pb-Free Solders: Alternatives and Implications / 980
47.5 Board Surface Finishes / 986
47.6 References / 994

Chapter 48. Solder Fluxes Gary M. Freedman 997
48.1 Introduction to Fluxes / 997
48.2 Flux Functions / 997
48.3 Flux Delivery Methods / 999
48.4 Flux Activity and Attributes / 999
48.5 Flux: Ideal versus Reality / 1000
48.6 Flux Types / 1000
48.7 Soldering Atmospheres / 1009
48.8 References / 1012

Chapter 49. Soldering Techniques Gary M. Freedman 1015
49.1 Introduction / 1015
49.2 Mass Soldering Methods / 1015
49.3 Oven Reflow Soldering / 1015
49.4 Wave Soldering / 1039
49.5 Wave Solder Defects / 1054
49.6 Vapor-Phase Reflow Soldering / 1055
49.7 Laser Reflow Soldering / 1057
49.8 Hot-Bar Soldering / 1064
49.9 Hot-Gas Soldering / 1069
49.10 Ultrasonic Soldering / 1071
49.11 References / 1072

Chapter 50. Soldering Repair and Rework Gary M. Freedman 1075
50.1 Introduction / 1075
50.2 Hot-Gas Repair / 1075
50.3 Manual Solder Fountain / 1080
50.4 Automated Solder Fountain (Single-Point Soldering) / 1080
50.5 Laser / 1080
50.6 Considerations for Repair / 1081
50.7 Reference / 1082

Part 9: Nonsolder Interconnection

Chapter 51. Press-Fit Interconnection Gary M. Freedman 1085
51.1 Introduction / 1085
51.2 The Rise of Press-Fit Technology / 1086
51.3 Compliant Pin Configurations / 1086
51.4 Press-Fit Considerations / 1089
51.5 Press-Fit Pin M
aterials / 1089
51.6 Surface Finishes and Effects / 1090
51.7 Equipment / 1093
51.8 Assembly Process / 1093
51.9 Rework for Press-Fit Connectors / 1096
51.10 PCB Design and Board Procurement Tips / 1098
51.11 Press-Fit Process Tips / 1099
51.12 Further Reading / 1101

Chapter 52. Pressure-Interconnect Land Grid Array Systems Gary M. Freedman 1103
52.1 Introduction / 1103
52.2 LGA and the Environment / 1103
52.3 Elements of the LGA System / 1103
52.4 Assembly / 1107
52.5 PCA Rework / 1109
52.6 Design Guidelines / 1110
52.7 Reference / 1110

Part 10: Quality

Chapter 53. Acceptability and Quality of Fabricated Boards Robert (Bob) Neves 1113
53.1 Introduction / 1113
53.2 Specific Quality and Acceptability Criteria by PCB Type / 1114
53.3 Methods for Verification of Acceptability / 1115
53.4 Inspection Lot Formation / 1116
53.5 Inspections Categories / 1117
53.6 Acceptability and Quality After Simulated Solder Cycle(s) / 1118
53.7 Nonconforming PCBs and Material Review Board Function / 1120
53.8 The Cost of the Assembled PCB / 1120
53.9 How to Develop Acceptability and Quality Criteria / 1121
53.10 Class of Service / 1122
53.11 Inspection Criteria / 1123
53.12 Reliability Inspection Using Accelerated Environmental Exposure / 1142

Chapter 54. Acceptability of Printed Circuit Board Assemblies Mel Parrish 1145
54.1 Understanding Customer Requirements / 1145
54.2 Handling to Protect the PCBA / 1150
54.3 PCBA Hardware Acceptability Considerations / 1153
54.4 Component Installation or Placement Requirements / 1158
54.5 Component and PCB Solderability Requirements / 1166
54.6 Solder-Related Defects / 1166
54.7 PCBA Laminate Condition, Cleanliness, and Marking Requirements / 1171
54.8 PCBA Coatings / 1174
54.9 Solderless Wrapping of Wire to Posts (Wire Wrap) / 1175
54.10 PCBA Modifications / 1176
54.11 References / 1178

Chapter 55. Asssembly Inspection Stacy Kalisz Johnson and Stig Oresjo 1179
55.1 Introduction / 1179
55.2 Definition of Defects, Faults, Process Indicators, and Potential Defects / 1181
55.3 Reasons for Inspection / 1182
55.4 Lead-Free Impact on Inspection / 1184
55.5 Miniaturization and Higher Complexity / 1185
55.6 Visual Inspection / 1186
55.7 Automated Inspection / 1189
55.8 Three-Dimensional Automated Solder Paste Inspection / 1191
55.9 Pre-Reflow AOI / 1193
55.10 Post-Reflow Automated Inspection / 1194
55.11 Implementation of Inspection Systems / 1199
55.12 Design Implications of Inspection Systems / 1200
55.13 References / 1201

Chapter 56. Design for Testing Kenneth P. Parker 1203
56.1 Introduction / 1203
56.2 Definitions / 1204
56.3 Ad Hoc Design for Testability / 1204
56.4 Structured Design for Testability / 1206
56.5 Standards-Based Testing / 1207
56.6 References / 1213

Chapter 57. Loaded Board Testing Kenneth P. Parker 1215
57.1 Introduction / 1215
57.2 The Process of Test / 1216
57.3 Definitions / 1217
57.4 Testing Approaches / 1221
57.5 In-Circuit Test Techniques / 1224
57.6 Alternatives to Conventional Electrical Tests / 1229
57.7 Tester Comparison / 1232
57.8 References / 1232

Chapter 58. Failure Modes and Effects Analysis Happy T. Holden 1233
58.1 Prognostics and Health Management / 1233
58.2 Theory / 1235
58.3 What Is Process FMEA? / 1241
58.4 Reference / 1244
58.5 Further Reading / 1244

Part 11: Reliability

Chapter 59. Conductive Anodic Filament Formation Laura J. Turbini and Antonio Caputo 1247
59.1 Introduction / 1247
59.2 Electrochemical Migration / 1247
59.3 Developing a Quantitative Copper Corrosion Test / 1249
59.4 Understanding CAF Formation / 1256
59.5 Factors That Affect CAF Formation / 1260
59.6 Test Method for CAF-Resistant Materials / 1266
59.7 Manufacturing Tolerance Considerations / 1267
59.8 References / 1267

Chapter 60. Reliability of Printed Circuit Boards Reza Ghaffarian 1271
60.1 Introduction / 1271
60.2 PCB and Microelectronics Trends and Reliability / 1272
60.3 PCB Fabrication and Failure Mechanisms / 1283
60.4 PTH Thermal Cycle Reliability and Projections Methods / 1294
60.5 Acknowledgments / 1322
60.6 References / 1322
60.7 Further Reading / 1325

Chapter 61. Reliability of Microvia Printed Circuit Boards Reza Ghaffarian 1327
61.1 Microvia Fabrication / 1327
61.2 Summary / 1342
61.3 List of Acronyms / 1342
61.4 Acknowledgments / 1345
61.5 References / 1345
61.6 Further Reading / 1346

Chapter 62. Component-to-PWB Reliability: The Impact of Design Variables and Lead Free Mudasir Ahmad and Mark Brillhart 1347
62.1 Introduction / 1347
62.2 Packaging Challenges / 1348
62.3 Variables That Impact Reliability / 1351
62.4 References / 1373

Chapter 63. Lead-Free Solder Joint Reliability: Fundamentals and Design-for-Reliability Rules Jean-Paul Clech 1375
63.1 Introduction / 1375
63.2 Reliability Definition and Goals / 1376
63.3 Why Do Solder Joints Fail? / 1377
63.4 Main Effects and Basic Rules-of-Thumb / 1378
63.5 Parameters That Affect Solder Joint Reliability Under Thermal Cycling Conditions / 1384
63.6 Significance of Board Parameter Effects / 1387
63.7 Lead-Free Reliability Trends / 1393
63.8 Conclusions / 1397
63.9 Further Reading / 1397

Chapter 64. Component-to-PWB Reliability: Estimating Solder Joint Reliability and the Impact of Lead-Free Solders Mudasir Ahmad and Mark Brillhart 1401
64.1 Introduction / 1401
64.2 Thermomechanical Reliability / 1403
64.3 Mechanical Reliability / 1418
64.4 Finite Element Analysis / 1425
64.5 References / 1432

Part 12: Flexible Circuits

Chapter 65. Flexible Circuit Applications and Materials Happy T. Holden 1439
65.1 Introduction to Flexible Circuits / 1439
65.2 Applications of Flexible Circuits / 1441
65.3 High-Density Flexible Circuits / 1442
65.4 Materials for Flexible Circuits / 1443
65.5 Substrate Material Properties / 1445
65.6 Conductor Materials / 1459
65.7 Copper-Clad Laminates / 1460
65.8 Coverlay Materials / 1464
65.9 Stiffener Materials / 1469
65.10 Adhesive Materials / 1469
65.11 Restriction of Hazardous Substances Issues / 1470
65.12 Acknowledgments / 1470

Chapter 66. Design of Flexible Circuits Happy T. Holden 1471
66.1 Introduction / 1471
66.2 Types of Flexible Circuits / 1472
66.3 Multilayer Rigid Flex (Multilayer Flex) / 1478
66.4 Circuit Designs for Flexibility / 1480
66.5 Electrical Design of the Circuits / 1485
66.6 Design of Flexible Printed Wiring with Transmission Line Properties / 1490
66.7 Circuit Designs for Higher Reliability / 1500
66.8 Acknowledgments / 1502

Chapter 67. Manufacturing Flexible Circuits Joseph Fjelstad 1503
67.1 Introduction / 1503
67.2 Fundamental Flex Circuit Processing Steps / 1504
67.3 Equipment for Wet Processing of Flexible Materials / 1507
67.4 Coverlayer/Cover-Coating Methods / 1509
67.5 Interconnection Surface Treatments / 1516
67.6 Depanelization of Flexible Circuits / 1517
67.7 Stiffener Processes / 1519
67.8 Packaging for Flex / 1520
67.9 High-Density Flexible Circuit Manufacturing / 1520
67.10 Acknowledgments / 1529

Chapter 68. Termination Options for Flexible Circuits Joseph Fjelstad 1531
68.1 Introduction / 1531
68.2 Wirebonding Technology / 1533
68.3 Solutions Where the Flex Circuit Is Half of the Mated Pair / 1536
68.4 Summary / 1541
68.5 Acknowledgments / 1541

Chapter 69. Multilayer Flex and Rigid Flex Joseph Fjelstad 1543
69.1 Introduction / 1543
69.2 Multilayer Flex versus Rigid Flex / 1543
69.3 Aluminum Rigid Flex Circuit—Prospective Structure for the Future / 1550
69.4 Summary / 1554
69.5 Acknowledgments / 1555

Chapter 70. Special Constructions of Flexible Circuits Dominique K. Numakura 1557
70.1 Introduction / 1557
70.2 Flying-Lead Construction / 1557
70.3 Tape Automated Bonding / 1564
70.4 Microbump Arrays / 1566
70.5 Thick-Film Conductor Flex Circuits / 1568
70.6 Shielding of the Flexible Cables / 1569
70.7 Functional Flexible Circuits / 1570

Chapter 71. Flexible Circuit Quality Assurance: Principles and Practices Joseph Fjelstad 1573
71.1 Introduction / 1573
71.2 Basic Concepts in Flexible Circuit Quality Assurance / 1574
71.3 Raw Material Testing / 1575
71.4 Electrical Performance Tests / 1576
71.5 General Testing Requirements for Flexible Circuit Materials / 1577
71.6 Flexible Circuit Visual Evaluation / 1577
71.7 Flexible Circuit Dimensional Requirements / 1578
71.8 Physical Testing Requirements for Flexible Circuits / 1579
71.9 Electrical Requirements for Flexible Circuits / 1581
71.10 Environmental Resistance Requirements / 1582
71.11 Solderability Requirements / 1582
71.12 Standards and Specifications for Flexible Circuits / 1582
71.13 Summary / 1584
71.14 Acknowledgments / 1584

Appendix: Summary of Key Component, Material, Process, and Design Standards Marc Carter 1585

Glossary 1595
Index 1605