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Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum ( )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

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Posted by: Sing Tay ( )
Date posted: Tue Apr 18 19:35:39 US/Eastern 2000
Subject: FIT rates, Temp and voltage acceleration factors in semiconductor devices
I just recently joined reliability engineering in this company and there have been discussions going on in trying to reduce BI or going to no-BI on some devices. I just want to find out from anybody out there who knows more about Temp and Voltage acceleration factors, how activation energies and beta values affect Temp and Voltage acceleration respectively. A more specific question would be do other companies set a generalized activation energy across all technology within the company or work is done to characterize the beta and Ea for each technology. Also, does anybody know how to design experiments to calculate these two parameters, or maybe can provide guidance to certain papers or books? Any feedback will be greatly appreciated. Please send an email to Thanks!


Subject: Burn-in, Accelerated Testing
Reply Posted by: Jack Farrell ( )
Organization: Reliability Analysis Center
Date Posted: Wed Apr 19 15:27:34 US/Eastern 2000
Let me break your questions down into several areas. ACCELERATED TESTING – An excellent reference for accelerated testing is Mil-Hdbk-338. Section 8.7 “Accelerated Testing” provides a good background and describes various accelerated test models including the Arrhenius Acceleration Model. Activation energies are also provided for some common semiconductor failure mechanisms. Mil-Hdbk-338 is available from RAC by calling 1-800-526-4802. The RAC also publishes a current awareness periodical called START. I found an edition that dealt with Accelerated Testing. It is accessible by following this link . ACTIVATION ENERGY – A paper entitled “Activation Energies and the Arrhenius Equation” by Finn Jensen was published in the 1985 Quality and Reliability Engineering International, Vol.1 No. 1. This paper described how activation energies may be computed from experimental data. As a minimum two experiments at different temperatures is required. The user is cautioned to ensure that the same failure mechanism is occurring at both temperatures. WEIBULL ANALYSIS – I am assuming the beta you are referring to is the weibull shape factor, commonly called beta. An excellent handbook for performing Weibull analsyis is “The New Weibull Handbook” by Dr. Robert Abernethy. This handbook is also available from the RAC. The following is a link to a website that lists beta’s for some common parts . BURN-IN – Dod-Hdbk-344 “Environmental Stress Screening of Electronic Equipment” presents an approach for developing an ESS regime tailored to a specific product. By tailoring ESS to a particular product you will minimize cost and time impacts. The handbook is available from National Technical Information Service by calling 703-605-6000.

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