Imagerie thermique et thermoélastique de circuits intégrés : application à l'analyse de défaillances

Ce travail décrit le développement d’une instrumentation en mesures thermiques et thermoélastiques pour l’analyse de défaillance sur circuits intégrés, il comporte trois parties : La première partie concerne des mesures interférométriques effectuées avec deux interféromètres, homodyne et hétérodyne. Ces interféromètres seront appliqués pour la détection de points chauds sur des circuits défaillants. La deuxième partie concerne des mesures thermiques effectuées en thermoréflectance. Deux bancs de mesure ont été développés : - le premier s’applique pour l’imagerie face avant. - le deuxième entièrement original, concerne l’imagerie large champ face arrière qui utilise une porte optique temporelle. La dernière partie concerne le développement d’une nouvelle approche pour les mesures de température et déplacement en utilisant la microscopie à balayage laser, avec une étude de résolution et sensibilité.This work describes the development of instrumentation in thermal and thermoelastic measurements for failure localisation and test diagnostic. It is divided in three parts: The first part is about interferometric measurements done with homodyne and heterodyne interferometers. Those interferometers were applied for defects localisation in failures ICs. The second part is about thermal measurements done with thermoreflectance. Two experimental benches were developed: - the first is applied for front side imaging - the second is a new technique applied for back side imaging, which is based on time gating. The last part of this work is about the development of a new approach for thermal and thermelastic measurements with the use of light scanning microscopy. It includes a study of the resolution and the sensitivity

Prediction and verification of process induced warpage of electronic packages

During the manufacturing, testing and service, thermally induced deformations and stresses will occur in IC devices and packages, which may cause various kinds of product failures. FEM techniques are widely used to predict the thermal deformations and stresses and their evolutions. However, due to the complexity of the real engineering problems, various assumptions and simplifications have to be made in conducting FEM modelling. Therefore, the applicability of the predicted results depend strongly on the reliability and accuracy of the developed FEM-based prediction models which should be verified before applications. In this paper, FEM models are developed to predict the thermal deformations of certain electronic packages and naked die samples under packaging and testing loading. For all the package constituents, appropriate material properties and models are used, including temperature-dependent visco-elasticity, anisotropy, and temperature-dependent elasticity and plasticity. To verify the developed FE models, a series of optical metrology tests are performed. A compact 3D interferometry testing system that can measure simultaneously out-of plane and in-plane deformations has been developed. Thermal deformation measurements are performed on samples of both real electronic packages and naked dies attached on a leadframe. Identical deformation patterns were found for the measured fringe patterns in the U-, V-, and W-fields and the simulated ones. Also, quantitatively, the maximum deformation mismatch between the predicted and tested results is within 15%. It is concluded that the thermally induced deformations predicted by the non-linear FEM models match well with measured deformations for both the naked die and the real packages