An analytical study of a novel and new failure mechanism observed in a high density CMOS ULSI device

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:260521

Pyle, R E; Kaushik, V; Laberge, P; Morris, S; Martin, L; Prack, E; Hance, R; Bridwell, J ^[1]

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1. Motorola Inc., Austin, TX (United States)

A Reliability Engineering group recently observed failures during a highly accelerated moisture stress test on high density CMOS ULSI devices. Failure Analysis traced the electrical failures to the column fuse area. It appeared from FIB (Focused Ion Beam)/SEM (Scanning Electron Microscopy) cross sections that corrosion of the third polycide tungsten silicide layer adjacent to some of the blown fuses had occurred. This had resulted in column failures in the redundancy circuits. To support the Product Group a comprehensive analytical study by the MOS Analytical Laboratories was invoked. The root cause of the observed failures was determined by AES analyses to be due to excessive oxygen within the tungsten silicide layer incorporated during wafer processing. It is believed that this excessive oxygen reacts with components of the tungsten silicide film and thereby destabilizes the film through excessive stress making it much more susceptible to chemical or electrochemical decomposition as observed. This paper will focus on the results of the comprehensive analytical investigation leading to this conclusion and will postulate a mechanism for this new and novel failure mechanism.

• OSTI ID: 260521
• Report Number(s): CONF-951156--; ISBN 0-87170-554-0
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
AUGER ELECTRON SPECTROSCOPY
DIAGNOSTIC TECHNIQUES
EXPERIMENTAL DATA
FABRICATION
FAILURES
INTEGRATED CIRCUITS
SYSTEM FAILURE ANALYSIS
TESTING