Microsystem Design

The goal of this book is to bring together into one accessible text the fundamentals of the many disciplines needed by today's engineer working in the field of microelectromechanical systems (MEMS). The subject matter is wide-ranging: microfabrication, mechanics, heat flow, electronics, noise, and dynamics of systems, with and without feedback. Because it is very difficult to enunciate principles of `good design' in the abstract, the book is organized around a set of Case Studies that are based on real products, or, where appropriately well-documented products could not be found, on thoroughly published prototype work. The Case Studies were selected to sample a multidimensional space: different manufacturing and fabrication methods, different device applications, and different physical effects used for transduction. The Case Study subjects are: the design and packaging of a piezoresistive pressure sensor, a capacitively-sensed accelerometer, a quartz piezoelectrically-driven and sensed rate gyroscope, two electrostatically-actuated optical projection displays, two microsystems for the amplification of DNA, and a catalytic sensor for combustible gases. This book is used for a graduate course in `Design and Fabrication of Microelectromechanical Devices (MEMS)' at the Massachusetts Institute of Technology. It is appropriate for textbook use by senior/graduate courses in MEMS, and will be a useful reference for the active MEMS professional. Each chapter is supplemented with homework problems and suggested related reading. In addition, the book is supported by a web site that will include additional homework exercises, suggested design problems and related teaching materials, and software used in the textbook examples and homework problems. The goal of this book is to bring together into one accessible text the fundamentals of the many disciplines needed by today's engineer working in the field of microelectromechanical systems (MEMS).

The subject matter is wide-ranging: microfabrication, mechanics, heat flow, electronics, noise, and dynamics of systems, with and without feedback. Because it is very difficult to enunciate principles of `good design' in the abstract, the book is organized around a set of Case Studies that are based on real products, or, where appropriately well-documented products could not be found, on thoroughly published prototype work.

The Case Studies were selected to sample a multidimensional space: different manufacturing and fabrication methods, different device applications, and different physical effects used for transduction. The Case Study subjects are: the design and packaging of a piezoresistive pressure sensor, a capacitively-sensed accelerometer, a quartz piezoelectrically-driven and sensed rate gyroscope, two electrostatically-actuated optical projection displays, two microsystems for the amplification of DNA, and a catalytic sensor for combustible gases.

This book is used for a graduate course in "Design and Fabrication of Microelectromechanical Devices (MEMS)" at the Massachusetts Institute of Technology. It is appropriate for textbook use by senior/graduate courses in MEMS, and will be a useful reference for the active MEMS professional.

Each chapter is supplemented with homework problems and suggested related reading. In addition, the book is supported by a web site that will include additional homework exercises, suggested design problems and related teachingmaterials, and software used in the textbook examples and homework problems.

It is a real pleasure to write the Foreword for this book, both because I have known and respected its author for many years and because I expect this book’s publication will mark an important milestone in the continuing worldwide development of microsystems. By bringing together all aspects of microsystem design, it can be expected to facilitate the training of not only a new generation of engineers, but perhaps a whole new type of engineer – one capable of addressing the complex range of problems involved in reducing entire systems to the micro- and nano-domains. This book breaks down disciplinary barriers to set the stage for systems we do not even dream of today. Microsystems have a long history, dating back to the earliest days of mic- electronics. While integrated circuits developed in the early 1960s, a number of laboratories worked to use the same technology base to form integrated sensors. The idea was to reduce cost and perhaps put the sensors and circuits together on the same chip. By the late-60s, integrated MOS-photodiode arrays had been developed for visible imaging, and silicon etching was being used to create thin diaphragms that could convert pressure into an electrical signal. By 1970, selective anisotropic etching was being used for diaphragm formation, retaining a thick silicon rim to absorb package-induced stresses. Impurity- and electrochemically-based etch-stops soon emerged, and "bulk micromachining" came into its own. Preliminaries......Page 1 Contents......Page 8 1 INTRODUCTION......Page 30 2 AN APPROACH TO MEMS DESIGN......Page 42 3 MICROFABRICATION......Page 56 4 PROCESS INTEGRATION......Page 106 5 LUMPED MODELING......Page 130 6 ENERGY-CONSERVING TRANSDUCERS......Page 152 7 DYNAMICS......Page 176 8 ELASTICITY......Page 210 9 STRUCTURES......Page 228 10 ENERGY METHODS......Page 266 11 DISSIPATION AND THE THERMAL ENERGY DOMAIN......Page 294 12 LUMPED MODELING OF DISSIPATIVE PROCESSES......Page 326 13 FLUIDS......Page 344 14 ELECTRONICS......Page 380 15 FEEDBACK SYSTEMS......Page 424 16 NOISE......Page 452 17 PACKAGING......Page 480 18 A PIEZORESISTIVE PRESSURE SENSOR......Page 496 19 A CAPACITIVE ACCELEROMETER......Page 524 20 ELECTROSTATIC PROJECTION DISPLAYS......Page 558 21 A PIEZOELECTRIC RATE GYROSCOPE......Page 588 22 DNA AMPLIFICATION......Page 632 23 A MICROBRIDGE GAS SENSOR......Page 656 Appendices......Page 678 References......Page 692 Index......Page 704 This text aims to bring together, in an accessible form, the fundamentals of the wide-ranging disciplines needed by engineers working in the field of micro-electromechanical systems (MEMS). The book is organized around a set of case studies based on real products or published prototype work