Integrated circuits failure mechanisms

Die passivation layers were first introduced to protect the metallisation of integrated circuits from mechanical damage during assembly. However, it soon became apparent that the passivation layer was a crucial factor in determining the failure rate in moist ambients. Originally, pure chemical vapour deposition (CVD) silicon dioxide was used, but later phosphorus was added to relieve strain in the layer and thus prevent cracking and loss of adhesion. There is also interest in, and limited use of, other forms of passivation such as silicon nitride, oxynitride and polyimide. 

A number of integrated circuit (IC) failure mechanisms are related to the presence of water and impurities at device surfaces. The most catastrophic failures are open or short circuits resulting from electrochemical attack on substrate metallization. Other, more subtle maladies include increased capacitive coupling between conductors (1.), reduced bipolar current gain (2), shifted MOS threshold voltages (3.4), and parasitic MOS devices (5.6). These problems arise from spurious electrical conduction processes in the presence of moisture and ionic contaminants. Polymer encapsulants, such as silicone rubber, provide barriers that prevent the formation of conductive water films on IC surfaces. 

This section describes a methodical procedure that allows reliability issues to be approached efficiently. MEMS reveal specific reliability aspects, which differ considerably from the reliability issues of integrated circuits and macroscopic devices. A classification of typical MEMS-failure modes is given, as well as an overview of lifetime distribution models. The extraction of reliability parameters is a Tack of failures situation using accelerated aging and suitable models. In a case study, the implementation of the methodology is illustrated with a real-fife example of dynamic mechanical stress on a thin membrane in a hot-film mass-airflow sensor. 

Hybrid devices are a combination of active components (microdrcuits or ICs) and various passive discrete parts mounted on a substrate and interconnected by conductive film traces. Hybrid failure mechanisms, Hke those of discrete and integrated circuits, are primarily due to manufacturing defects. Failures will occur whether the device is operating or dormant. Various accelerating environments, such as temperature or vibration can reveal the failure mechanisms before parts are shipped (or used in drcuits). Table 7.10 Hsts the accelerating environments and the problems they reveal. 

Electronic Components Selection and Apphcation Guidelines, by Victor Meeldijk, John WHey and Sons Interscience Division, (C) 1995. The integrated circuits chapter discusses IC packages, lead material, and failure mechanisms related to packaging. 

In 2001, a failure of control rod transponder circuit boards at Kashiwazaki-Kariwa Nuclear Power Station Unit 5 (Japan) rendered the control rods inoperable [2]. Following detection of the defective cards, an analysis revealed that the failure mechanism was aluminum wire breakage in the integrated circuits caused by electro... 

AEC—QlOO Failure mechanism based stress test qualification for integrated circuits Relevant for the qualification of the electronic integrated circuits of a CMS (e.g., the imago-in the camera)... 

N. Biunno, A Root Cause Failure Mechanism for Solder Joint Integrity of Electroless Nickel/Immersion Gold Surface Finishes, Proceedings of the IPC Printed Circuit Expo, Paper S18-5, March 14-18, 1999... 

Various failure and degradation mechanism have been identified that adversely impact the integrity of bolts used in safety related applications and in applications important to safety. Depending on the nature of the degradation mechanism a potential for common mode failures exists for same system or redundant system components. In addition, leaks from flanged joints represent a significant part of total number of leaks in primary circuit. 

Defence in depth is assured by redundant and diverse barriers to the release of radionuclides from the fuel, in combination with provisions to ensure the integrity of the barriers. The barrier structure is based on the properties of the fuel to retain a significant fraction of each of the radionuclides deposited in the fuel pellet, and mainly, on the prevention of radioactivity release to the primary coolant by fuel rod claddings. For this purpose, the absence of pellet-clad mechanical interaction is ensured during the fuel lifetime and in accidents, to reduce the probability of clad failure. An additional barrier preventing the release of radionuclides is the two-circuit NSSS scheme. 

The purpose of the substrates is to support discrete active components, integrated and passive circuits, capacitors, resistors, varistors, thermistors etc. connected by conducting tracks. The coefficients of expansion of the different materials must be as close as possible in order to avoid the appearance of stresses of thermal origin, susceptible to induce failure of the circuit. Roughness is also an important parameter. It therefore appears that the choice of a material for making a substrate must take into account not only electronic requirements, but also mechanical, thermal and even chemical requirements. 

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