New ultra low load indentation device with extremely low thermal drift: principle and experimental results

Nanoindentation has become an indispensable method for measuring the mechanical properties of small volumes of materials. It has gained importance in several domains such as thin film science, electronics and materials research. Despite continuous evolution of the nanoindentation technique over the past fifteen years, contemporary methods still suffer serious drawbacks, particularly long thermal stabilization and thermal drift which limit the duration of the measurements to only a short period of time. The presented paper introduces a novel ultra nanoindentation method that utilizes loads from the μN range up to 50 mN, is capable of performing long term stable measurements and has negligible frame compliance. The method is based on a novel patented design which uses an active top referencing system and components made from Zerodur$^{\circledR}$ glass. Several materials including fused silica, DLC and selected polymers were used to show the performance of the method. The tests were performed mainly at low loads to demonstrate the low load and displacement capabilities of the instrument. A large number of tests were performed with a hold at the maximum indentation load to observe the instrument thermal drift. It was proved that indentations with maximum loads in μN range and penetration depth of a few nm can be easily performed with this method. The measurements with hold at maximum load confirm extremely low levels of instrument thermal drift. The presented Ultra Nanoindentation Tester opens new possibilities for testing thin films and long term testing including creep of polymers at very high resolution without the need of long thermal stabilization

Mechanical properties of a plasma-modified porous low-k material

International audienceFor 45 nm and beyond microelectronics technology nodes, the integration of porous low dielectric constant (low-k) materials is now required to reach integrated dielectric constant values lower than 2.7. However, porous low-k materials have lower mechanical strength in comparison with traditional dense materials and are also affected by chemical diffusion through the interconnected porosity during the various integration processes. Different types of plasma post-treatments which lead to surface modification of the porous low-k material with possible formation of a top surface layer, change of surface structure and “pore sealing” effect were applied. Highly sensitive instruments for mechanical investigation of thin layers, such as the Ultra Nano Hardness Tester (UNHT) and Nano Scratch Tester (NST) were applied for characterization of the effect of the plasma post-treatments on the mechanical behavior of a porous low-k material. Preliminary results are presented and discussed in this paper

Cross-layer Optimization in the Next-generation Broadband Satellite Systems

Next-generation broadband satellite systems will have the capability to provide cost-effective universal broadband access for the users. In order to meet users’ requirements on high quality multimedia services, many enhancements have to be made on the existing satellite technologies. One of the promising methods is the introduction of cross-layer design. There are several advantages of a layered approach since modularity, robustness and ease of designs are achieved without difficulty. However the properties of the different layers have substantial interdependencies and a modularised design may therefore be suboptimal with regards to performance and availability in a hybrid satellite and mobile wireless environment. In this paper, we will carry out a review of the cross-layer design in satellite systems. Based on this, a cross-layer architecture for the next-generation broadband satellite system is proposed. The proposed cross-layer architecture has two main components: QoS and resource management and mobility management. In each component, the cross-layer techniques that have been used are described in details

Cross-layer optimization in the next-generation broadband satellite systems

Next-generation broadband satellite systems will have the capability to provide costeffective universal broadband access for the users. In order to meet users' requirements on high quality multimedia services, many enhancements have to be made on the existing satellite technologies. One of the promising methods is the introduction of cross-layer design. There are several advantages of a layered approach since modularity, robustness and ease of designs are achieved without difficulty. However the properties of the different layers have substantial interdependencies and a modularised design may therefore be suboptimal with regards to performance and availability in a hybrid satellite and mobile wireless environment. In this paper, we will carry out a review of the cross-layer design in satellite systems. Based on this, a cross-layer architecture for the next-generation broadband satellite system is proposed. The proposed cross-layer architecture has two main components: QoS and resource management and mobility management. In each component, the cross-layer techniques that have been used are described in details