10.6 Summary and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
11 Fundamentals of Solder Alloys in 3D Packaging . . . . . . . . . . . . . . . 329
Kwang-Lung Lin
11.1 The Microbumping Process . . . . . . . . . . . . . . . . . . . . . . . . . . . 329
11.2 The Solder Alloys in Microbump . . . . . . . . . . . . . . . . . . . . . . 333
11.3 The Formation of Intermetallic Compounds in the as-Produced
Microbump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
11.4 Microstructure Variation of Microbump Under Thermal
Mechanical Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
11.5 The Microstructure and Failure Mechanism of Microbump . . . . 341
11.6 Summary and Future Challenge . . . . . . . . . . . . . . . . . . . . . . . . 342
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 344
12 Fundamentals of Electromigration in Interconnects
of 3D Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
Pilin Liu
12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
12.2 Key Modulators for EM in Solder Joints . . . . . . . . . . . . . . . . . 348
12.2.1 Typical EM Fail Caused by Sn Diffusion . . . . . . . . . . 348
12.2.2 EM Fail Caused by Metallization Dissolution . . . . . . . 351
12.3 EM in Solder Joints of 3D Packaging . . . . . . . . . . . . . . . . . . . 355
12.3.1 EM Damage Due to Sn Flux Divergence
in Micro Bumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355
12.3.2 The Transformation of Full IMC Joint Under EM . . . . 357
12.3.3 Thermomigration Accompanied by EM . . . . . . . . . . . . 359
12.4 EM in TSV of 3D Packaging . . . . . . . . . . . . . . . . . . . . . . . . . 361
12.4.1 EM for Cu Damascene Interconnects . . . . . . . . . . . . . . 362
12.4.2 EM Failure in TSV . . . . . . . . . . . . . . . . . . . . . . . . . . 363
12.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366
13 Fundamentals of Heat Dissipation in 3D IC Packaging and
Thermal-Aware Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369
Satish G. Kandlikar and Amlan Ganguly
13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369
13.2 Thermal Performance Parameters for 3D ICs . . . . . . . . . . . . . . 372
13.3 Air Cooling of 3D ICs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
13.4 Jet Impingement and Spray Cooling . . . . . . . . . . . . . . . . . . . . 373
13.5 Microchannel Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374
13.6 Thermal Design Considerations in 3D IC Architectures . . . . . . . 375
13.6.1 Thermal Considerations in TSV Placements . . . . . . . . . 376
13.6.2 Thermal Analysis Tools for 3D ICs . . . . . . . . . . . . . . . 377
13.6.3 Performance Considerations . . . . . . . . . . . . . . . . . . . . 377
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