SMTA International Conference Proceedings

A Closed-Form Norris-Landzberg Solder Reliability Model

Authors: Emad S. Al-Momani, Ph.D., Mohammad T. Khasawneh, Ph.D. and Bahgat Sammakia, Ph.D.
Company: Intel Corporation and Binghamton University
Date Published: 9/28/2014   Conference: SMTA International

Abstract: Solder joint fatigue reliability under thermal cycling (TC) conditions has been a vital area of research for several decades. The Norris-Landzberg (NL) model (1969) is an acceleration factor model that has served the electronics community for years. Once actual accelerated thermal testing is performed, the results can be projected for the same package under other cycling conditions using the NL model.

This paper presents the transformation of the original NL model into a closed-form solder joint fatigue reliability model. The proposed model does not require actual thermal cycling testing as in the original model and its modification trials. Instead, the model uses package/PCB design attributes. This modification will eliminate the lengthy thermal cycling testing and will also enable acceleration between two different packages, which is not possible in the original NL model. If thermal cycling results are available, the proposed model can still be used to predict reliability under other thermal cycling condition as in the original NL model.

Key Words: 

reliability, modeling, solder, accelerated thermal cycle (ATC)

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