Molecular dynamics simulation of observed c(4x4) and c(4x3) C60 alignments on the Si(100) reconstructed surface.

We have implemented a large-scale classical molecular dynamics simulation at constant temperature to provide a theoretical insight into the results of a recently performed experiment on the monolayer and multi-layer formations of molecular films on the Si(100) reconstructed dimerized surface. Our simulation has successfully reproduced all of the morphologies observed on the monolayer film by this experiment. We have obtained the formation of both c(4 4) and c(4 3) structures of the molecules and have also obtained phase transitions of the former into the latter.

Stencil printing at sub-100 microns pitch

This article presents the latest print results at less than 100 microns pitch obtained in stencil printing type 6 and 7 lead-free solder pastes and conductive adhesives. The advantages of the microengineered stencil arc presented and compared with other bonding technologies. Characterisation of the print deposits is presented and future applications of stencil printing are described.

Stencil printing at sub-100 microns pitch

This article presents the latest print results at less than 100 microns pitch obtained in stencil printing type 6 and 7 leadfree solder pastes and conductive adhesives. The advantages of the microengineered stencil are presented and compared with other bonding technologies. Characterisation of the print deposits is presented and future applications of stencil printing are described.

Computational modelling for reliable flip-chip packaging at sub-100 micron pitch using isotropic conductive adhesives

This paper presents the assembly process using next generation electroformed stencils and Isotropic Conductive Adhesives (ICAs) as interconnection material. The utilisation of ICAs in flip-chip assembly process is investigated as an alternative to the lead and lead-free solder alloys and aims to ensure a low temperature (T < 100 °C) assembly process. The paper emphasizes and discusses in details the assembly of a flip-chip package based on copper columns bumped die and substrate with stencil printed ICA deposits at sub-100 μm pitch. A computational modelling approach is undertaken to provide comprehensive results on reliability trends of ICA joints subject to thermal cycling of the flip-chip assembly based on easy to use damage criteria and damage evaluation. Important design parameters in the package are selected and investigated using numerical modelling techniques to provide knowledge and understanding of their impact on the thermo-mechanical behaviour of the flip-chip ICA joints. Sensitivity analysis of the damage in the adhesive material is also carried out. Optimal design rules for enhanced performance and improved thermo-mechanical reliability of ICA assembled flip-chip packages are finally formulated.