Engineering the CMOS Library: Enhancing Digital Design Kits for Competitive Silicon

Shows readers how to gain the competitive edge in the integratedcircuit marketplace

This book offers a wholly unique perspective on the digitaldesign kit. It points to hidden value in the safety margins ofstandard–cell libraries and shows design engineers and managers howto use this knowledge to beat the competition.

Engineering the CMOS Library reveals step by step how thegeneric, foundry–provided standard–cell library is built, and howto extract value from existing std–cells and EDA tools in order toproduce tighter–margined, smaller, faster, less power–hungry, andmore yield–producing integrated circuits. It explores all aspectsof the digital design kit, including the different views of CMOSstd–cell libraries along with coverage of IO libraries, memorycompilers, and small analog blocks. Readers will learn:

How to work with overdesigned std–cell libraries to improveprofitability while maintaining safety

How functions usually found in std–cell libraries cover thedesign environment, and how to add any missing functions

How to harness the characterization technique used by vendors toadd characterization without having to get it from the vendor

How to use verification and validation techniques to ensureproper descriptive views and even fix inconsistencies in vendorrelease views

How to correct for possible conflicts arising from multipleversions and different vendor sources in any given integratedcircuit design

Complete with real–world case studies, examples, and suggestionsfor further research, Engineering the CMOS Library will helpreaders become more astute designers.

ACKNOWLEDGMENTS xiii

1 INTRODUCTION 1

1.1 Adding Project–Specific Functions, Drive Strengths, Views,and Corners 4

1.2 What Is a DDK? 5

2 STDCELL LIBRARIES 9

2.1 Lesson from the Real World: Manager′s Perspective andEngineer′s Perspective 9

2.2 What Is a Stdcell? 11

2.3 Extended Library Offerings 32

2.4 Boutique Library Offerings 36

2.5 Concepts for Further Study 37

3 IO LIBRARIES 39

3.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 39

3.2 Extension Capable Architectures versus Function CompleteArchitectures 40

3.3 Electrostatic Discharge Considerations 43

3.4 Concepts for Further Study 50

4 MEMORY COMPILERS 52

4.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 52

4.2 Single Ports, Dual Ports, and ROM: The Compiler 55

4.3 Nonvolatile Memories: The Block 58

4.4 Special–Purpose Memories: The Custom 60

4.5 Concepts for Further Study 62

5 OTHER FUNCTIONS 63

5.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 63

5.2 Phase–Locked Loops, Power–On Resets, and Other Small–ScaleIntegration Analogs 66

5.3 Low–Power Support Structures 69

5.4 Stitching Structures 71

5.5 Hard, Firm, and Soft Boxes 75

5.6 Concepts for Further Study 78

6 PHYSICAL VIEWS 80

6.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 80

6.2 Picking an Architecture 82

6.3 Measuring Density 86

6.4 The Need and the Way to Work with Fabrication Houses 89

6.5 Concepts for Further Study 92

7 SPICE 95

7.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 95

7.2 Why a Tool More Than 40 Years Old Is Still Useful 99

7.3 Accuracy, Reality, and Why SPICE Results Must be Viewed witha Wary Eye 102

7.4 Sufficient Parasitics 106

7.5 Concepts for Further Study 107

8 TIMING VIEWS 109

8.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 109

8.2 Performance Limits and Measurement 110

8.3 Default Versus Conditional Arcs 110

8.4 Break–Point Optimization 112

8.5 A Word on Setup and Hold 115

8.6 Failure Mechanisms and Roll–Off 122

8.7 Supporting Efficient Synthesis 124

8.8 Supporting Efficient Timing Closure 131

8.9 Design Corner Specific Timing Views 134

8.10 Nonlinear Timing Views are so "Old Hat" . . . 140

8.11 Concepts for Further Study 142

9 POWER VIEWS 145

9.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 145

9.2 Timing Arcs Versus Power Arcs 147

9.3 Static Power 148

9.4 Real Versus Measured Dynamic Power 150

9.5 Should Power Be Built as a Monotonic Array? 153

9.6 Best–Case and Worst–case Power Views Versus Best–Case andWorst–Case Timing Views 155

9.7 Efficiently Measuring Power 156

9.8 Concepts for Further Study 158

10 NOISE VIEWS 160

10.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 160

10.2 Noise Arcs Versus Timing and Power Arcs 162

10.3 The Easy Part 165

10.4 The Not–So–Easy Part 166

10.5 Concepts for Further Study 168

11 LOGICAL VIEWS 170

11.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 170

11.2 Consistency Across Simulators 171

11.2.1 Efficient Testing 175

11.3 Consistency with Timing, Power & Noise Views 177

11.4 Concepts for Further Study 180

12 TEST VIEWS 181

12.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 181

12.2 Supporting Reachability 184

12.3 Supporting Observability 189

12.4 Concepts for Further Study 191

13 CONSISTENCY 193

13.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 193

13.2 Validating Views across a Library 195

13.3 Validating Stdcells Across a Technology Node 199

13.4 Validating Libraries Across Multiple Technology Nodes204

13.5 Concepts for Further Study 208

14 DESIGN FOR MANUFACTURABILITY 209

14.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 209

14.2 What is DFM? 211

14.3 Concepts for Further Study 224

15 VALIDATION 226

15.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 226

15.2 Quality Levels 229

15.3 Concepts for Further Study 236

16 PLAYING WITH THE PHYSICAL DESIGN KIT: USUALLY "AT YOUR OWNRISK" 237

16.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 237

16.2 Manipulating Models 240

16.3 Added Unsupported Devices 243

16.4 Concepts for Further Study 245

17 TAGGING AND REVISIONING 247

17.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 247

17.2 Tagging and Time Stamps 248

17.3 Metadata, Directory Structures, and Pointers 254

17.4 Concepts for Further Study 258

18 RELEASING AND SUPPORTING 260

18.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 260

18.2 When Is Test Silicon Needed for Verification? 263

18.3 Sending the Baby Out the Door 265

18.4 Multiple Quality Levels on the Same Design 269

18.5 Supporting "Bug Fixes" 271

18.6 Concepts for Further Study 274

19 OTHER TOPICS 276

19.1 Lesson from the Real World: The Manager′s Perspective andthe Engineer′s Perspective 276

19.2 Supporting High–Speed Design 279

19.3 Supporting Low–Power Design 283

19.4 Supporting Third–Party Libraries 286

19.5 Supporting Black Box Third–Party IP (Intellectual Property)Design 289

19.6 Supporting Multiple Library Design 292

19.7 Concepts for Further Study 293

20 COMMUNICATIONS 295

20.1 Manager′s Perspective 295

20.2 Customer′s Perspective 298

20.3 Vendor′s Perspective 300

20.4 Engineer′s Perspective 301

20.5 Concepts for Further Study 302

20.6 Conclusions 302

APPENDIX I MINIMUM LIBRARY SYNTHESIS VERSUS FULL–LIBRARYSYNTHESIS OF A FOUR–BIT FLASH ADDER 305

APPENDIX II PERTINENT CMOS BSIM SPICE PARAMETERS WITH UNITS ANDDEFAULT LEVELS 311

APPENDIX III DEFINITION OF TERMS 313

APPENDIX IV ONE POSSIBLE MEANS OF FORMALIZED

MONTHLY REPORTING 317

INDEX 319

David Doman is Circuit Manager at GlobalFoundries in Austin, Texas. He has more than thirty years of experience in semiconductor intellectual property design and development.