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Unformatted text preview: nment — note corner features to use instead • Evidence of test probing — before or after release? Microsystems Packaging: An Introduction Page 92 © 2003 Sandia National Laboratories Another Example • S150 bulk micromachined infrared detector from Dexter Research Center • Welded TO can package with optical window • Proprietary infrared absorbing layer (black) Microsystems Packaging: An Introduction Page 93 © 2003 Sandia National Laboratories 3rd Example: Package with Integrated Circuitry PD SMM VCSEL Microsystems Packaging: An Introduction Page 94 © 2003 Sandia National Laboratories ASIC The Product Design Process • Packaging critical to MEMS products! • Establish technology, performance, cost limits • Many dimensions of tradeoffs – package/device combination to yield a cost-effective manufacturable product – don’t constrain package by emphasizing device design only • Brainstorm solutions to tradeoffs • Evaluate several device/package combinations to determine best solution • No easy “one size fits all” solutions available • These challenges can be met! Microsystems Packaging: An Introduction Page 95 © 2003 Sandia National Laboratories True Story (details changed to protect the guilty) • A customer wanted to vacuum seal his polysilicon resonators • We have a vacuum sealing capability • We can do getter activation to prevent outgassing (outgassing, not real leaks is the main reason for slow pressure increases in vacuum systems) • Problem: the resonators have gold metallization (Au:Si eutectic is 370°C and there is significant diffusion below this temperature) • Problem: Common solders melt at 350°C • Problem: Epoxy cure temperature for low outgassing is 350°C • Getter activation is at 500°C for 10 minutes or 350°C for 6 hours We now have a significant process development effort for both sealing and getters that could have been avoided if the customer had used a different metal Microsystems Packaging: An Introduction Page 96 © 2003 Sandia National Laboratories Packaging Questions for Designers • How does the device interface with the outside world? • What is the final stage that you want your device to reach? – – – – – Probe station Table scratcher for boss Mock-up for a customer Small scale production Large scale production • What is the yield that you want to achieve? • How much money do you want to spend on each device (an ounce of prevention is worth a pound of cur...
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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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