Advanced MEMS Packaging

John H. Lau received his Ph.D. degree in Theoretical and Applied Mechanics from the University of Illinois (1977), a M.A.Sc. degree in Structural Engineering from the University of British Columbia (1973), a second M.S. degree in Engineering Physics from the University of Wisconsin (1974), and a third M.S. degree in Management Science from Fairleigh Dickinson University (1981). He also has a B.E. degree in Civil Engineering from National Taiwan University (1970). John is an interconnection technology scientist at Agilent Technologies, Inc. His current interests cover a broad range of electronic and optoelectronic packaging and manufacturing technology. Prior to Agilent, he worked for Express Packaging Systems, Hewlett-Packard Company, Sandia National Laboratory, Bechtel Power Corporation, and Exxon Production and Research Company. With more than 30 years of R&D and manufacturing experience in the electronics, petroleum, nuclear, and defense industries, he has given over 200 workshops, authored and co-authored over 180 peer reviewed technical publications, and is the author and editor of 13 books: Solder Joint Reliability; Handbook of Tape Automated Bonding; Thermal Stress and Strain in Microelectronics Packaging; The Mechanics of Solder Alloy Interconnects; Handbook of Fine Pitch Surface Mount Technology; Chip On Board Technologies for Multichip Modules; Ball Grid Array Technology; Flip Chip Technologies; Solder Joint Reliability of BGA, CSP, Flip Chip, and Fine Pitch SMT Assemblies; Electronics Packaging: Design, Materials, Process, and Reliability; Chip Scale Package (CSP): Design, Materials, Process, Reliability, and Applications; Low Cost Flip Chip Technologies for DCA, WLCSP, and PBGA Assemblies, and Microvias for Low Cost, High Density Interconnects. John served as one of the associate editors of the IEEE Transactions on Components, Packaging, and Manufacturing Technology and ASME Transactions, Journal of Electronic Packaging. He also served as general chairman, program chairman, and session chairman, and invited speaker of several IEEE, ASME, ASM, MRS, IMAPS, SEMI, and SMI International conferences. He received a few awards from ASME and IEEE for best papers and outstanding technical achievements, and is an ASME Fellow and an IEEE Fellow. He is listed in American Men and Women of Science and Who’s Who in America.

• Chapter 1 Introduction to MEMS1.1 Introduction1.2 Commercial Applications of MEMS1.3 MEMS Markets1.4 Top 30 MEMS Suppliers1.5 Introduction to MEMS Packaging1.6 MEMS Packaging Patents Since 20011.6.1 US MEMS Packaging Patents1.6.2 Japan MEMS Packaging Patents1.6.3 Worldwide MEMS Packaging Patents1.7 ReferencesChapter 2 Advanced MEMS Packaging2.1 Introduction2.2 Advanced IC Packaging2.2.1 Moore’s Law vs. More Than Moore2.2.2 3D IC Integration and WLP2.2.3 Low-Cost Solder Microbumps for 3D IC SiP2.2.4 Thermal Management of 3D IC SiP with TSV2.3 Advanced MEMS Packaging2.3.1 3D MEMS WLP – Designs and Materials2.3.2 3D MEMS WLP – Processes2.4 ReferencesChapter 3 Enabling Technologies for Advanced MEMS Packaging3.1 Introduction3.2 TSV for MEMS Packaging3.2.1 Via formations3.2.2 Dielectric Isolation Layer (SiO2) Deposition3.2.3 Barrier/Adhesion and Seed Metal Layer Deposition3.2.4 Via Filling3.2.5 Cu polishing by Chemical/Mechanical polish (CMP)3.2.6 Fabrication of ASIC Wafer with TSV3.2.7 Fabrication of Cap Wafer with TSV and Cavity3.3 Piezoresistive Stress Sensors for MEMS Packaging3.3.1 Design and Fabrication of Piezoresistive Stress Sensors3.3.2 Calibration of Stress Sensors3.3.3 Stresses in Wafers After Mounting on a Dicing Tape3.3.4 Stresses in Wafers After Thinning (Back-Grinding)3.4 MEMS Wafer Thinning and Thin-Wafer Handling3.4.1 3M Wafer Support System3.4.2 EV Group’s Temporary Bonding and DeBonding System3.4.3 A Simple Support-Wafer Method for Thin Wafer Handling3.5 Low-Temperature Bonding for MEMS Packaging3.5.1 How Does Low Temperature Bonding with Solders Work?3.5.2 Low Temperature C2C Bonding2.5.3 Low Temperature C2W Bonding2.5.4 Low Temperature W2W Bonding3.6 MEMS Wafer Dicing3.6.1 Fundamentals of Stealth Dicing (SD) Technology3.6.2 Dicing of SOI Wafers3.6.3 Dicing of Silicon-on-Silicon Wafers3.6.4 Dicing of Silicon-on-Glass Wafers3.7 RoHS Compliant MEMS Packaging3.7.1 EU RoHS3.7.2 What is the Definition of X-free, e.g., Pb-free?3.7.3 What is a Homogeneous Material?3.7.4 What is the TAC?3.7.5 How a Law is Published in EU RoHS?3.7.6 EU RoHS Exemptions3.7.7 Current Status of RoHS Compliance in the Electronics Industry3.7.8 Lead-Free Solder Joint Reliability of MEMS Packages3.8 ReferencesChapter 4 Advanced MEMS Wafer Level Packaging4.1 Introduction4.2 Micromachining, Wafer Bonding Technologies and Interconnects4.2.1 Thin Film Technologies4.2.2 Bulk Micromachining Technologies4.2.3 Conventional Wafer Bonding Technologies for Packaging4.2.4 Plasma Assisted Wafer Bonding Technology4.2.5 Electrical Interconnects4.2.6 Solder Based Intermediate Layer Wafer Bonding Technology4. 3 Wafer Level Encapsulation4.3.1 High Temperature Encapsulation Process4.3.2 Low Temperature Encapsulation Process4. 4 Wafer Level Chip Capping and MCM Technologies4. 5 Wafer Level MEMS Packaging Based on Low Temperature Solders – Case Study4.5.1 Case study – In/Ag system of non-eutectic composition4.5.2 Case study – Eutectic InSn solder for Cu/Ni/Au based metallization4.6 Summary and Future Outlooks4.7 ReferencesChapter 5 Optical MEMS Packaging - Communications5.1 Introduction5.2 Actuation Mechanisms and Integrated Micromachining Processes5.2.1 Electrostatic Actuation5.2.2 Thermal Actuation5.2.3 Magnetic Actuation5.2.4 Piezoelectric Actuation5.2.5 Integrated Micromachining Processes5.3 Optical Switches5.3.1 Small Scale Optical Switches5.3.2 Large Scale Optical Switches5.4 Variable Optical Attenuators5.4.1 Early Development Works5.4.2 Surface Micromachined VOAs5.4.3 DRIE Derived Planar VOAs Using Electrostatic Actuators5.4.4 DRIE Derived Planar VOAs Using Electrothermal (Thermal) Actuators5.4.5 3-D VOAs5.4.6 VOAs Using Various Mechanisms5.5 Packaging, Testing and Reliability Issues5.5.1 Manufacturability and Self-assembly5.5.2 Case Study – VOAs5.5.3 Case Study – Optical Switches5.6 Summary and Future Outlooks5.7 ReferencesChapter 6 Optical MEMS Packaging - Bubble Switch6.1 Introduction6.2 3D Optical MEMS Packaging6.3 Boundary Value Problem6.3.1 Geometry6.3.2 Materials6.3.3 Loading Conditions6.4 Nonlinear Analyses of the 3D Photonic Switch6.4.1 Creep Hysteresis Loops6.4.2 Deflections6.4.3 Shear Stress Time-History6.4.4 Shear Creep Strain Time-History6.4.5 Creep Strain Energy Density Range6.5 Isothermal Fatigue Tests and Results6.5.1 Sample Preparation6.5.2 Test Set-Up and Procedures6.5.3 Test Results6.6 Thermal-Fatigue Life Prediction of the Sealing Ring6.7 Summary6.8 Appendix A: Package Deflection by Twyman-Green Interferometry Method6.9.1 Sample Preparation6.9.2 Test Setup and Procedure6.9.3 Temperature Conditions6.9.4 Measurement Results6.9 Appendix B: Package Deflection by Finite Element Method6.10 Appendix C: Finite Element Modeling of the Bolt6.11.1 Description of Bolted Model6.11.2 Responses of Bolted Photonic Switch6.11 ReferencesChapter 7 Bolometer MEMS Packaging7.1 Introduction7.2 Bolometer chip7.3 Thermal optimization7.3.1 Final temperature stability testing7.4 Structural optimization of package7.5 Vacuum packaging of Bolometer7.5.1 Ge Window7.6 Getter attachment and activation7.7 Outgassing study in a Vacuum package7.8 Testing set up for Bolometer7.9 Image testing7.10 ReferencesChapter 8: Bio MEMS Packaging8.1 Introduction8.2 BioMEMS chip8.3 Micro fluidic components8.3.1 Micro fluidic cartridge8.3.2 Biocompatible polymeric materials8.4 Microfluidic Packaging8.4.1 Polymer microfabrication techniques8.4.2 Replication technologies8.4.3 Overview of existing DNA and RNA extractor bio-cartridges8.5 Fabrication of PDMS layers8.6 Assembly of PDMS microfluidic packages8.6.1 Microfluidic package with out reservoirs8.6.2 Development of Reservoir and Valve8.7 Self contained Micro fluidic cartridge8.7.1 Micro fluidic package with self contained reservoirs8.7.2 Reservoir design for controlled fluid flow8.7.3 Pin valve design8.7.4 Fluid Flow control Mechanism8.8 Fabrication8.8.1. Substrate fabrication8.8.2. Material selection for the reservoir membrane8.9 Permeability of material8.10 Thermo Compression Bonding8.10.1 Bonding of PMMA to PMMA for Channel layer8.10.2 Polypropylene to PMMA for Reservoir and channel layer8.10.3 Tensile Test8.11 Microfluidic Package Testing8.11.1 Fluidic testing8.11.2 Biological Testing on bio-sample8.12 Sample Preparation and Set Up8.12.1 Pre treatment of the cartridge8.12.2 DNA Extraction8.12.3 PCR amplification8.13 ReferencesChapter 9 Bio Sensor MEMS Packaging9.1 Introduction9.1.1 Review of Optical Coherence Tomography9.2 Biosensor packaging9.2.1 Upper Substrate9.2.2 Single Mode Optical Fiber and Graded Index Lens9.2.3 Lower Substrate9.2.4 Micro Mirror9.3 The Package9.3.1 The Configuration of the Probe9.3.2 Optical Properties and Theories9.3.3 Evaluations of Parameters9.4 Optical Simulation9.4.1 Optical model of the Probe9.4.2 Effect of Mirror Curvature to Coupling Efficiency9.4.3 Effect of Lateral Tilt in Flat Micro Mirror on a Curved Sample9.4.4 Effect of Vertical Tilt in Flat Micro Mirror on a Curved Sample9.4.5 Effect of Vertical Tilt in Flat Micro Mirror on a Flat Sample9.5 Assembly of Optical probe9.5.1 Fabrication of SiOB9.5.2 Probe Assembly9.5.3 Probe Housing9.6 Testing of the Probe9.6.1 Optical Alignment9.6.2Axial Scanning Test Result9.6.3 Probe imaging9.6.4 Optical Efficiency Testing9.7 ReferencesChapter 10 Accelerometer MEMS Packaging10.1 Introduction10.2 Wafer level package requirements10.2.1 Electrical modeling10.2.2 Package structure10.2.3 Extraction methodology of the interconnection characteristics10.3 Wafer level packaging Process10.4 Wafer Separation Process10.4.1 Process Integration10.5 Sacrificial wafer removal process10.6 Wafer level vacuum sealing10.7 Vacuum measurement using MEMS motion analyzer (MMA)10.8 Reliability Testing – Vacuum maintenance10.9 Wafer level 3D package for Accelerometer10.10 ReferencesChapter 11 RF MEMS Switches11.1 Introduction11.2 Design of RF MEMS Switches11.2.1Electromagnetic modelling of capacitive switches11.2.2Electromagnetic modelling of metal-contact switches11.2.3Mechanical design of RF MEMS switches11.3 Fabrication of RF MEMS Switches11.3.1Surface micromachining of RF MEMS switches11.3.2Bulk micromachining of RF MEMS switches11.4 Characterization of RF MEMS switches11.4.1RF performance11.4.2Mechanical performance11.5 Reliability of RF MEMS Switch11.5.1Reliability of capacitive switches11.5.2Reliability of metal-contact switches11.6 Power Handling of RF MEMS Switches11.6.1Power handling of capacitive switches11.6.2Power handling of metal-contact switches11.7 Summary11.8 ReferencesChapter 12 RF MEMS Tunable Circuits12.1 Introduction12.2 RF MEMS Tunable Capacitors12.2.1Analog tuning of RF MEMS capacitors12.2.2Digital tuning of RF MEMS capacitors12.3 RF MEMS Tunable Band-Pass Filters12.3.1Analog tuning of RF MEMS band-pass filters12.3.2Digital tuning of RF MEMS band-pass filters12.4 Summary12.5 ReferencesChapter 13 Advanced Packaging of RF MEMS13.1 Introduction13.2 Zero-Level Packaging13.2.1Chip capping13.2.2Thin film capping13.3 First–Level Packaging13.4 Reliability of Packaged RF MEMS Devices13.5 Summary13.6 References