Reliability of RoHS-Compliant 2D and 3D 1С Interconnects

Transcription

1 Reliability of RoHS-Compliant 2D and 3D 1С Interconnects John H. Lau, Ph.D. New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto

2 Foreword Preface Acknowledgments xxi xxiii xxvii Introduction to RoHS-Compliant Semiconductor and Packaging Technologies Introduction Electronics Industry С Semiconductor Technology D 1С Packaging Technology Conventional 1С Packaging Technology D 1С Packaging Technology D 1С Integration Technology FEOL, BEOL, and MEOL More Than Moore D 1С Integration Technology Critical Issues of 3-D 1С Integration TSV, With or Without RDL Manufacturing Process for TSV 3-D 1С Integration How to Improve TSV Manufacturing Yield? Thin-Wafer Handling Low-Cost, Lead-Free Solder Microbumps Thermal Management of 3-D 1С Integration D 1С Packaging versus 3-D 1С Integration D Si Integration Technology D 1С Integration versus 3-D Si Integration W2W (Cu-to-Cu) Bonding W2W (Si0 2 -to-si0 2 ) Bonding Future Outlook of 3-D Si Integration Who Is Going to Make the TSV for 3-D 1С Integration? 42 vii

3 VÜi Contents 1.8 Notes on TSV Manufacturing Costs EU RoHS Update EU RoHS EU Restricted Substances EU Product Category EU Exemptions China RoHS Update China RoHS China Standards China's Product Catalogue China Compulsory Certificate (CCC) Impact of RoHS on the Electronics Industry References 49 2 Reliability Engineering of Lead-Free Interconnects Introduction Reliability Basics Definition of Reliability Objective of Reliability Tests Life Distributions Reliability, Failure Rate, and MTTF Simple System Reliability Ranking True Weibull Slopes True Characteristic Life True Mean Life Comparison of the MTTF of Two Different Sets of Samples Accelerated Models Acceleration Factors Reliability Engineering of Lead-Free Interconnects Reliability Testing and Data Analysis Failure Analysis Failure Analysis Methods D X-ray Inspections and Analyses of PBG A Lead-Free Interconnects Design for Reliability (DFR) Advantages of DFR A Note on DFR Material Properties of Lead-Free Solder Interconnects 116

4 jx Effects of Halogen on Solderability and Reliability of SAC Solder Pastes Creep, Young Modulus, CTE, and Poisson's Ratio of SnAgCu and Other Solders Isothermal Fatigue Tests of WLCSP Lead-Free Interconnects Isothermal Fatigue Tests of PBGA Lead-Free Interconnects at 6CPC Thermal-Fatigue Life Predictions of Lead-Free Interconnects Quality of Lead-Free Solder Interconnects References Notes on Failure Criteria Introduction Failure Criteria Resistance Measurements Three-Cycle Moving Average (TCMA) Method Summary and Recommendations References Reliability of 1657-Pin CCGA Lead-Free Solder Joints Introduction Design for Reliability of the 1657CCGA with Lead-Free Solder Paste The Structure Material Properties Temperature Boundary Conditions Simulation Results Thermal-Fatigue Life Prediction Summary and Recommendations Reliability Testing and Data Analyses of the 1657CCGA with Lead-Free Solder Paste Component and Test Boards Test Chamber and Temperature Cycling Condition Data Acquisition System and Failure Criterion Statistical Analysis of 1657CCGA Solder Joints Summary and Recommendations

5 4.4 Failure Analyses of 1657CCGA Assemblies Failure Analyses of CCGA with SAC and SnPb Solder Pastes Summary and Recommendations References Reliability of PBGA Lead-Free Solder Joints (With and Without Underfills) Introduction Reliability of PBGA SAC Solder Joints With and Without Underfills under Thermal Cycling Condition Components, Test Board, and Underfills Design for Reliability Test Chamber and Temperature-Cycling Profile Data Acquisition, Failure Criterion, and Data Extraction Weibull Slope, Characteristic Life, and MTTF from Test Samples True Characteristic Life True MTTF True Weibull Slope Comparison of MTTF from Two Sets of Test Samples Failure Analyses Summary Reliability of PBGA SAC Solder Joints With and Without Underfills under Drop Condition Drop Test Setup, Data Acquisition, and Drop Profile Failure Criterion Strain Time-History During Drop Impact Weibull Slope, Characteristic Life, and MTTF from Test Samples True Characteristic Life True MTTF True Weibull Slope Effects of Aging and Underfill on the Reliability of PBGA Interconnects under Drop Impacts 236

6 5.3.9 Failure Analysis Summary References 241 Reliability of LED Lead-Free Interconnects Introduction LED Seven-Segment Display Family Lead-Free Wave Soldering of LED Displays PCB Flux and Solder Bar Lead-Free Wave-Soldering Thermal Profiles Thermal Cycling Test of LED Display Assemblies C/85%RH Test of LED Display Assemblies Creep Analysis of the LED Display Lead-Free Solder Joints The Structure Material Properties Constitutive Equations Boundary Conditions Deformation of the LED Assembly Stress and Creep Strain Distributions Stress Time-History Creep Strain Time-History Hysteresis Loops and Creep Strain Energy Density Thermal-Fatigue Life of LED Solder Joints Summary and Recommendations D LED and 1С Integration D LED and 1С Integration Packages Manufacturing Process of 3-D LED and 1С WLP Thermal Management of 3-D LED and 1С Integration System Summary and Recommendations References 272

7 tents Reliability of VCSEL Lead-Free Interconnects Introduction Lead-Free Interconnect Reliability of a VCSEL under Transient and Steady-State Loadings The Structure Materials Heat-Transfer Analysis and Results Thermal-Stress Analysis and Results Summary and Recommendations Lead-Free Interconnect Reliability of a VSCEL on an Optical PCB Optical Design and Analysis Thermal Design and Analysis Lead-Free Interconnect Reliability Summary and Recommendation References 309 Reliability of Low-Temperature Lead-Free (SnBiAg) Solder Joints Introduction Benefits of Using SnBiAg Low-Temperature Alloy Cost Reduction Product Reliability Design Flexibility Concerns with Use of Bismuth-Based Solders Brittleness Availability Environmental Impact Recyclability Lead Contamination Design for Reliability Problem Definition Material Properties Temperature Condition Results and Discussion Reliability Testing and Data Analyses Components and Test Board Board Assembly Process Post-Assembly Inspection 322

8 xiü Air-to-Air Temperature Cycling (АТС) Tests Results of АТС Tests Shock (Drop) Tests and Results Vibration Tests and Results Failure Analyses Summary and Recommendations References Reliability of Lead-Free (SACX) Solder Joints Introduction SACC Material Properties of SACC Bulk Solder Test Specimen Tensile Test Procedures Tensile Test Results Equations for Young's Modulus and Yield Stress SnAgCu (SAC) versus SnAgCuCe (SACC) Creep Test and Data Summary and Recommendations Intermetallic Compounds of SACC Sample Preparation Tests and Measurements IMC on OSP Surface Finish IMC on NiAu Surface Finish SnAgCu (SAC) versus SnAgCuCe (SACC) Summary and Recommendations Process Development of SACC with Various Packages Components and PCBs Printing Characteristics Reflow Temperatures Voids Four-Point Bending Fatigue Tests Summary and Recommendations Mechanical Pull Test of PQFP with SACC Solder Joints Mechanical Pull Test Setup Pull Test Results Failure Analyses 377

9 XJV Contents 9.7 Thermal Cycling Test of SACC Solder Joints 381* Components and Test Boards Э Thermal Cycling Test Thermal Cycling Test Results Finite-Element Analysis and Results Summary and Recommendations References Chip-to-Wafer (C2W) Bonding and Lead-Free Interconnect Reliability Introduction D Packaging (PoP) with AuSn Interconnects Test Vehicle and Fabrication Test Vehicle Test Vehicle Fabrication C2W PoP Assembly Bump Height Coplanarity Alignment Accuracy C2W Design of Experiments (DOE) Three-Factor DOE DOE Results Reliability Tests and Results Summary and Recommendations D Packaging (PoP) with SnAg Interconnects Low-Temperature C2W (InSnAu) Bonding for 3-D 1С Chip Stacking How Does Low-Temperature Bonding with Solder Work? Solder Design Test Vehicle D 1С Chip Stacking with InSnAu Low-Temperature Bonding SEM, ТЕМ, XDR, and DSC of the InSnAu IMC Young's Modulus and Hardness of the InSnAu IMC Three-Time Reflows of the InSnAu IMC Shear Strength of the InSnAu IMC 418

10 XV Electrical Resistance of the InSnAu IMC When Does the InSnAu IMC Become Unstable? Summary and Recommendations References 422 Wafer-to-Wafer (W2W) Bonding and Lead-Free Interconnect Reliability Introduction Low-Temperature W2W Bonding with Snln Solder on CuTiAu Metallization Pads The Test Vehicle Test Vehicle Fabrication Low-TemperatureW2WBonding C-SAM Inspection Microstructure by SEM/EDX/ FIB/ТЕМ Helium Leak Rate Tests and Results Reliability Tests and Results Summary and Recommendations W2W Bonding with AuSn Solder and TiCuNiAu Metallization Pads The Test Vehicle Test Vehicle Fabrication W2W Bonding Electrical Performance Quality and Reliability Summary and Recommendations References 450 Through-Silicon-Via (TSV) Interposer Reliability Introduction DFR of the Cu Thickness in Toshiba's TSV Finite-Element Modeling Modeling Results and Analyses Other Considerations TSV Reliability Due to Local Thermal Expansion Mismatch Boundary-Value Problems DFR Results 460

11 tents TSV with Redistribution Layer Summary and Recommendations TSV Reliability Due to Global Thermal Expansion Mismatch D Boundary-Value Problem Summary and Recommendations D Boundary-Value Problem D Analysis Results Summary and Recommendations Reliability Test and Failure Analysis of a 2.5D 1С Integration SiP with a TSV Interposer Underfill Materials Thermal Cycling Test and Results Failure Analysis Summary and Recommendations Thermal-Enhanced and Cost-Effective 3-D 1С Integration SiP with a TSV Interposer Introduction Design Philosophy The New Designs A 3-D 1С Integration SiP Design Example for Demonstration Modeling of the 3-D 1С Integration SiP Design Example Thermal Analyses and Results of the 3-D 1С Integration SiP Nonlinear Stress Analyses and Results of the 3-D 1С Integration SiP Summary and Recommendations References 501 Electromigration of Lead-Free Microbumps for 3-D 1С Integration Introduction Test Vehicles and Methods Solder Bumps Test Methods Test Procedures Microstructures of Samples Before Tests Samples Tested at 140 C C with Low Current Density 509

12 XVÜ Samples Tested at 140 C with Current Density of 2.04 x 10 4 A/cm Microstructures of Samples Tested at Low Current Density Samples Tested at 140 C with High Current Density Samples Tested at 140 C with Current Density of 4.08 xlo 4 A/cm Microstructures of Samples Tested at High Current Density Failure Mechanism of the Multiphase Solder-Joint Interconnect Summary and Recommendations References 516 Effects of Dwell Time and Ramp Rate on SAC Thermal Cycling Test Results Introduction Effects of Dwell Time on the Thermal-Fatigue Life of SnAgCu (SAC) Solder Joints The Structure, Material Properties, and Simulations Temperature Loading Conditions Creep Hysteresis Loops Shear Stress Time-History Shear Creep Strain Time-History Creep Strain Energy Density Time-History Summary and Recommendations Effects of Ramp Rate on the Thermal- Fatigue Life of SAC Solder Joints Temperature Loading Conditions Maximum Stress/Strain Location Creep Hysteresis Loops Shear Stress Time-History Shear Creep Strain Time-History Creep Strain Energy Density Time-History Summary and Recommendations References 534

13 tents Effects of High Strain Rate (Impact) on SAC Solder Balls/Bumps Introduction Angled High-Speed Ball Shear Test of SnAgCu Solder Balled/Bumped Package Apparatus Setup with High-Speed Shear Tester Test Specimens and Sample Preparation Test Results Characterizations of Failure Samples Comparison of SAC305 and SAC Finite-Element Analyses of Angled High-Speed Ball Shear of the SnAgCu Solder-Balled Package Finite-Element Modeling Finite-Element Analysis and Results Summary and Recommendations References 552 Effects of Voids on Solder Joint Reliability Introduction Effects of Voids on BCC-H- Solder Joint Reliability The BCC-H-Package and Structure Finite-Element Analyses Analysis Results Effects of Voids on Crack Growth J-Integral Evaluation around a Crack Tip J-Integral for Various Crack Lengths without Voids J-Integral for a Fixed Crack Length with Various Void Sizes J-Integral for Various Crack Lengths and Void Sizes D versus 3-D Solutions Summary and Recommendations Effects of Voids on WLCSP Solder Joint Reliability The Structure and Simulations 572

14 xix Effects of Cracks on the Reliability of WLCSP Solder Joints Effects of Voids on the Reliability of WLCSP Solder Joints D versus 3-D Solutions Summary and Recommendations References 580 Index 583