thin film

Summer Job for Students in Europe: NSF-sponsored International Research Experience for Students (IRES)
International US-European Joint Study of X-Ray Optics Thermomechanical Stability and Control

A thin film subject to compressive strain can either bend (for large strain gradient) or wrinkle (for small strain gradient). The bending is traditionally used in thermostats (bimetal stripes), but couple of years ago, it was extended to the nanoscale thin films which can bend and roll-up to tubes with defined number of rotations. The wrinkles are also rather common in macro- and microscale thin films.
Here, we developed an equilibrium phase diagram for the shape of
compressively strained free-hanging films by total strain energy
minimization.

An electronic device integrates diverse materials, and inevitably contains sharp features, such as interfaces and corners. When the device is subject to thermal and mechanical loads, the corners develop intense stress and are vulnerable sites to initiate failure. This paper analyzes stress fields at corners in flip-chip packages. The stress at a corner is a linear superposition of two modes of singular fields, with one mode being more singular than the other. The amplitudes of the two modes are represented by two stress intensity factors of dissimilar dimensions.

In this paper, we report comprehensive experimental and theoretical
studies of bending in structures relevant to inorganic flexible electronics.
Different from previous mechanics models of related systems, our analysis does not
assume the thin film to cover the entire substrate, thereby explicitly
accounting for effects of edges and finite device sizes, both of which play
critically important roles in the mechanics and bending properties. These
thin-film islands give nonuniform stress, with maxima that often appear at the
edges and spatially non-uniform shear and normal stresses along the film/substrate
interface. Although these results are generally applicable to all classes of

POST-DOCTORAL RESEARCH POSITION IN ENVIRONMENTAL ENGINEERING AND MATERIALS SCIENCE

School of Engineering and Applied Sciences, Harvard University

POST-DOCTORAL RESEARCH POSITION IN EXPERIMENTAL MATERIALS SCIENCE

School of Engineering and Applied Sciences, Harvard University

The Harvard School of Engineering and Applied Sciences seeks highly qualified applicants for a post-doctoral research position in experimental materials science.  The successful candidate will participate in a project to design an apparatus for high-temperature calorimetry on nanoscale quantities of materials. This apparatus will be used to study phase transformations in complex ternary and quaternary materials systems.

We have recently studied the atomic scale structural stability of
freestanding wavy gold (Au) nanofilms using molecular dynamics
simulations. In recent years, wavy or patterned structurs have shown great promise for applications in various emerging technologies including fuel cells
engineering, tissue engineering, biomedical engineering, creation
of counterfeit-resistant documents , nanolithography in microelectronics, optoelectronics, nanomachinesand many others. It is out of question that the success of these novel applications lies on one crucial factor – the

This is a fully funded research project at the University of Waterloo, Canada. The objective is to construct a PECVD and a UV cure chambers for porous dielectric thin film depositions. In addition to building chambers, the candidate will conduct experiments in thin film fracture and small scale deformation. Please email your CV to tttsui@uwaterloo.ca

Integrating porous low-permittivity dielectrics into Cu metallization is one of the strategies to reduce power consumption, signal propagation delays, and crosstalk between interconnects for the next generation of integrated circuits. However, the porosity and pore structure of these low-k dielectric materials also strongly affects other important material properties besides their dielectric constant.

Many studies on the thin film/substrate structure and its failure mechanism were reported in recent years. The direct experimental results of thin film/substrate structure by scanning electron microscopy (SEM) presents an intriguing problem:there exists a buckling failure mechanism at the lateral edge of metal film under pure bending. The qualitative theoretical analysis has been done on such buckling failure of thin film/substrate structure.

This symposium is part of the Spring 2008 ACS National Meeting and Exposition , to be held at New Orleans, Louisiana, from Sunday, April 6 to Thursday, April 10, 2008.

Organizers: Christopher M. Stafford (NIST), Adam J. Nolte (NIST), Rui Huang (UT Austin)

Sponsors: ACS Division of Polymeric Materials: Science and Engineering (PMSE) and National Science Foundation

Technical Program: