Created: 10/24/95 Updated: 4/18/97

Project Number: C96-20

Health Management of Electronic Systems

Point of Contact: Dr. Michael Pecht
email: pecht@calce.umd.edu
Phone: (301) 405-5323
Fax: (301) 314-9269
 
Objective Background Work Accomplished

 Objective

Develop an approach to Health Management of Electronic Systems in order to

Background

Conventional stochastic and mechanistic approach to failure analysis requires information about potential failure modes, mechanisms and sites, so that proper modifications can be made to eliminate these faults. Physics-of-Failure (PoF) approach alone, designs the system for working under the worst-case conditions, since the actual field stresses are unknown. These approaches to failure analysis are applicable only after the failure has occurred and are not useful where detailed information about the failure is not available. In the electronic systems, failure causes are often characterized as assignable causes and non-assignable causes.

Assignable causes can be clearly analyzed in terms of failure mechanisms, failure modes and failure sites. Non-assignable causes are described as can-not-duplicate CND, retest OK, cannot verify, or unknown causes, and are responsible for up to 70 percent of failures, primary reason being the lack of knowledge about the field conditions. The result is that the potential failure mechanisms may be overlooked in the design process. In terms of root cause failure analysis, incompatibility of the testing conditions and working conditions may make failure detection impossible. The detection and diagnosis of potential non- assignable, as well as assignable, failures in electronic systems demands (1) defect growth characterization, (2) on-line, nondestructive health management techniques, and (3) failure models from which to assess remaining life. Health management will characterize degradation and on-line diagnostic techniques in conjunction with the physics-of-failure approach predict the reliability of the system.

Previous work (C95-20) developed a Health Management and Early Detection Fuse (HMEDF) for conductive filament formation (CFF). To assess feasibility of the approach for failures in electronic systems, critical failures and their symptoms were identified. Failures were classified and ranked according to the severity and frequency of their occurrence. Following is the approach for achieving successful health management of the system.
 

Work Accomplished