Laboratories develop predictive reliability models

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Unformatted text preview: e) • Do you want to package additional components with your device? • Remember, there are few off the shelf packaging solutions • The earlier you involve the packaging and the processing people in your design, the better the end product Microsystems Packaging: An Introduction Page 97 © 2003 Sandia National Laboratories Conclusion Slide • Talk to the packaging engineers, while you design the device • MEMS Packaging is different than IC Packaging • Packaging is an important part of the design of the device and the system • There are few standard packages and packaging technologies for MEMS • The #1 packaging problem we have at Sandia is designers who ask us to package their devices after the devices are designed Microsystems Packaging: An Introduction Page 98 © 2003 Sandia National Laboratories MEMS Challenges: Qualification Is Key to Success • MEMS failure mechanisms are more varied than for IC • MEMS might include moving, impacting and rubbing surfaces • Better understanding of these failure mechanisms is needed Identify Failure Modes Statistical Characterization Design Test Structures Microsystems Packaging: An Introduction Page 99 © 2003 Sandia National Laboratories Develop Predictive Reliability Models What Should YOU Know About Packaging? • MEMS Packaging is different than IC Packaging • Packaging is an important part of the design of the device and the system • Outline – Quick review of packaging technologies and design issues – release? – new processes • The #1 packaging problem at Sandia is designers who ask us to package their devices after the device is designed Microsystems Packaging: An Introduction Page 100 © 2003 Sandia National Laboratories Microelectronics (Not MEMS) Packaging Packages provide: • Mechanical support – Silicon is brittle • Electrical connections • Thermal management • Protection from the environment – Lifetime and reliability • Internal environment – Internal dewpoint below 0° C • For electronics, the principal interaction with the outside world is through electrical signals Microsystems Packaging: An Introduction Page 101 © 2003 Sandia National Laboratories An Overview of IC Packaging: • Because most MEMS are still based on IC technology, we can use IC technology as a starting point. For ICs we follow these steps: – Mechanically attach to package: Die Attach – Electrically attach to package: Wire Bond – Enclose, encapsulate, seal package – Functional test at package level – Sell Microsystems Packaging: An Introduction Page 102 © 2003 Sandia National Laboratories IC Fabrication Processes: Packaging IC Packaging processes: • Wafer dicing (diamond saw) • Wire bonding from pads to pins • Multi-chip modules and flip-chip bonding • Hermetic sealing • Potting to protect from shock and vibration Of particular interest to MEMS processes: • Wafer dicing before or after release? • Multi-chip modules and flip-chip bonding for hybrid integration • Exposing sensors and actuators to hostile environments (while protecting circuitry) • Potting to protect from shock & vibration • Precise orientation of inertial sensors Microsystems Packaging: An Introduction Page 103 © 2003 Sandia National Laboratories MEMS Packaging can be Complicated: • • • • Mechanical and electrical connections are needed Thermal issues less of a problem than ICs, in general Many MEMS interact in ways other than electrically with their environment Some of the issues: – gas or fluid interconnects – sensor integration – fiber/optical interconnects or integration – vacuum packaging – precision alignments (accelerometers, mirrors) • • • • MEMS packages often contain multiple chips MEMS packaging and processing are very related – An example would be the release etch of surface micromachines Packaging and testing are also related since both occur at the end of the process Another important issue for non-standard devices is the micromachining or the release step Microsystems Packaging: An Introduction Page 104 © 2003 Sandia National Laboratories Handling Individual Die • Free micromachines – Sensitive to particles – Damage due to N2 or freon dusters • Die handling – Soft tweezers: edge handling easier if MEMS in center – Vacuum collet: could be custom to each MEMS design, must leave room on die for contact • Die attach worries – mechanical scrub to get adhesion Microsystems Packaging: An Introduction Page 105 © 2003 Sandia National Laboratories Bad place to put tweezers...
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This note was uploaded on 09/02/2010 for the course MEEN 5050 taught by Professor Himanshuj.sant during the Spring '10 term at University of Utah.

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