Mems technology suitable clear edges with no thin

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Unformatted text preview: e due to N2 or Freon • 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 53 © 2003 Sandia National Laboratories Advanced Design Issues: Handling • Tweezers: – No MEMS close to edge as a tweezer target! – MEMS technology suitable — clear edges with no thin loose layers for tweezers to crush? • Vacuum collets: – Space around MEMS for vacuum collet? – Space can include bondpads, circuitry, etc. • ADXL150 – Plenty of room around MEMS – Vacuum collet likely Microsystems Packaging: An Introduction Page 54 © 2003 Sandia National Laboratories Pick and Place • Less damage to die • More accurate die placement • Does require pick up areas to be designed into MEMS die and information on current fixtures Microsystems Packaging: An Introduction Page 55 © 2003 Sandia National Laboratories Pick and Place (2) Single module layout for large quantity automated die packaging • Must have a blank 375 µm2 area in each corner of the design space for automated pick/place tooling touchdown • We are developing fixtures and rules for double modules • This information is current as of April 2003, contact a packaging engineer for current specifications Microsystems Packaging: An Introduction Page 56 © 2003 Sandia National Laboratories Die Attach, Chip to Package • Solder — Eutectic Au/Si (370°C), Au/Sn (280°C) – Inorganic, good thermal, electrical conductivity – Requires backside metal, produces high stress • Ag glass – Inorganic (some binder), lower stress than Au/Si – Long (~90 min), hot (>400°C), oxidizing ambient processing; solvent/binder outgassing, brittle • Epoxies (70-80% Ag, silica filled) – Lowest thermal stress – Desires native oxide (or Ti/Au) back – Typical cure 150°C, 30-60 minutes – If outgassing controlled, good solution for MEMS Microsystems Packaging: An Introduction Page 57 © 2003 Sandia National Laboratories Advanced Design Issues: Die Attach • Will stress impact MEMS performance? • Will temperature cycle (eutectic and glass) impact MEMS performance (e.g. SAM coating) • Electrical and thermal performance issues? • ADXL150 – Clearly uses epoxy die attach – Design would be sensitive to substrate bending Package MEMS Circuitry Wire Bond Microsystems P...
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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 Utah.

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