If after release how to protect during separation

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Unformatted text preview: von Arx, University of Michigan Release Process Issues • SUMMiT™ release in an HF solution – Long release times Change in Contact Angle (Θ i-Θ f) – Obey design rules on etch release holes! 60 50 40 30 20 10 0 -10 220 260 300 340 380 420 460 500 540 580 Temperature (C) Chemical A Chemical D Si3 • Drying options: – Air dry – SAM coating to make hydrophobic – Supercritical CO2 – Sublimation drying • Coatings: – SAM coatings – Wear resistant coatings Microsystems Packaging: An Introduction Page 72 © 2003 Sandia National Laboratories temperature dependence of the contact angle of a SAMS coated surface as a function of temperature Advanced Design Issues: Die Separation • Separate before or after release? • If after release, how to protect during separation? – Glass cap – Area around MEMS for temporary protection – Get scribe and break to work • If before release, how are you measuring yield? – Can’t do wafer level test, so then what? • Chip layout on wafer, die size, etc. Microsystems Packaging: An Introduction Page 73 © 2003 Sandia National Laboratories Bulk Micromachined Infrared Imager • Micromachined first • Then break • Then package Device from Dexter Research Center Inc. Microsystems Packaging: An Introduction Page 74 © 2003 Sandia National Laboratories Alternative Die Separation and Handling Technique (Design Rules at End of Handout) • Package MEMS at the wafer level • Then dice and handle them like regular IC die Microsystems Packaging: An Introduction Page 75 © 2003 Sandia National Laboratories Design for “Packagability” of MEMS: • The developer of a MEMS device desires... – a large number of functional, testable, packaged parts – devices that can be operated in a manner that yields useful information for yield/design enhancement • SUMMiT V™ MEMS – need free space to operate – have polysilicon pads for wirebond interconnections – It is logical to assume that these devices will end up in some sort of cavity package (cerdip, TO, etc.) • Sandia has high-rel packaging experience – We like ceramic packages with brazed-on lids Microsystems Packaging: An Introduction Page 76 © 2003 Sandia National Laboratories Your Design Includes the Package! • As part of the design process, the in...
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