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Abstract: Reliability assessment of components, integrated circuits or micro-assemblied devices, is undoubtedly identified as one of the major factors conditioning the on-going development of microelectronics. In the same way, growing market penetration by nanotechnologies is clearly related to the imperative demonstration of satisfactory built-in operational reliability with respect to actual severe standards. This situation requires a specific effort on built-in reliability. These considerations must be integrated, as early as possible at the beginning of the development ‘top-down’ and the ‘bottom-up’ approaches. Reliability issues cover extremely large scientific fields such as physics, material science, electrical transport, thermal phenomena, coupling interfaces between optics and electronics, statistical models, etc. The objective of this paper deals with the presentation of new, original methodologies for reliability assessment, coming from studies in the IMS Laboratory, in close collaboration with industrial and academic partners. These new approaches are based on the combination of the physical laws of failure, behavioral simulations and statistical methods, adding inevitable parametric dispersions to extrapolate failure rates and lifetime in operating conditions. Some results are presented and analyzed on micro-assemblied technologies and photonic components for high-rate optical links. The main goal is to discuss their potentiality and applicability field with a view to intrinsic nanodevices reliability assessment in operating conditions. To cite this article: L. Béchou et al., C. R. Physique 9 (2008). [Copyright &y& Elsevier]

Reliability assessment of conductive adhesive bonds by thermo-cycling up to 830 cycles is time consuming, and does not give much information about the details of the onset of degradation. There is a need for faster tests giving more details about degradation. In this paper, low frequency noise of such contacts is investigated. 1/f Noise stems from conductance fluctuations. The observed voltage noise is enhanced due to current crowding in the electrical contacts on a microscopic scale. In this research contact bonds were made and compared of isotropic conductive adhesives from three suppliers. The 1/f noise of the contact resistance can be interpreted in terms of a multispot contact behavior. We investigated the relative noise C versus contact resistance R in two ways: (1) after an increasing number of thermo-cycles; (2) after increasing mechanical stress. The results often show an increase in relative noise of three orders of magnitude for poor quality polymer bonds. A maximum increase of one order of magnitude is observed for the best quality conductive adhesive. The contact resistance increases by a factor 1.7 and not more than 1.14 for the poor and best quality bonds, respectively. From the analysis based on a noise model for multispot contact, the onset of delamination can be characterized as a reduction in electrical contact area Ae. The relative noise is proportional to Ae-5/2. The surprising result is that samples submitted to a mechanical stress show pictures similar to thermocycled samples. Thermo-cycling with less than 200 cycles leads to less noise, an increase in electrical contact area, and hence a contact improvement. This behavior is understood. Noise analysis under mechanical stress on nondegraded or slightly cycled bonds is a fast diagnostic tool for reliability characterization. The degree of delamination is expressed quantitatively by the D-factor D=Aemax /Aemin≅(Cmax/Cmin)2/5 [ABSTRACT FROM PUBLISHER]