ÿþ<html><head> <title>On Ultra-Fine Leak Detection of Hermetic Wafer Level Packages </title></head> <body bgcolor="#ffffff"> <center><i>IEEE Transactions on Advanced Packaging, Vol. 31, No. 1, pp. 14-21, 2008</i> <br><h2>On Ultra-Fine Leak Detection of Hermetic Wafer Level Packages</h2> <br><br><b>Arindam Goswami</b><br>and<br><b>Bongtae Han</b><br> </center> <b>Abstract:</b> <p>Theoretical and practical ranges of leak rates measurable by the helium mass spectrometer are characterized. The effect of noise due to: 1) background helium present in the spectrometer and 2) desorption of helium that attaches itself to the specimen surface during bombing is quantified experimentally. The results guide a framework to extract the true leak rate from the measured leak rate profile. An optical interferometry based hermeticity measurement technique for ultra-fine leaks is proposed. The setup to implement the technique is described and a preliminary experimental result is reported. </p> <p><b>Index Terms:</b> Helium fine leak test, hermeticity, optical interferometry, theoretical and practical limits, true leak rate.</p> <p><a href="../../fulltext/2008/Hermeticity_Review.pdf">Complete article</a> is available to CALCE Consortium Members.</p> <p><font size="-2"><font color="red">ýÿ IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.</font></font> </p> <hr><br> <center> [<a href="http://www.calce.umd.edu">Home Page</a>] [<a href="../../">Articles Page</a>] </center> <center><font size="-1">Copyright ýÿ 2008 by CALCE and the University of Maryland, All Rights Reserved </font></center> </body></html>