Advanced Interconnect Systems Research Articles

Silicon Photonics for Advanced Optical Interconnections

After a brief review on silicon photonics research and development in China, the progress of silicon photonic components for coherent transceiver is described in details. The performance of the silicon modulators in high capacity, low-cost advanced intensity modulation and direct detection optical interconnection systems is also reported, and special properties of silicon photonic components, which lead to low power consumption, are discussed. These results show that silicon photonics has great prospect in advanced optical interconnection systems.

Modeling of TDDB in advanced Cu interconnect systems under BTS conditions

Due to the shrinking of the device size in integrated circuits together with the use of novel, less stable low-k back-end-of-line dielectrics more attention has to be paid to the time dependent dielectric breakdown (TDDB) effect. In this work the TDDB mechanisms are investigated and modeled based on constant-voltage bias-temperature stress (BTS) experiments from the 90nm and 45nm technology nodes. The modeling of the I-t dependencies is based on the numerical model of Haase in which it is assumed that the degradation of the dielectric is caused just by the electronic leakage current itself. By two simple modifications of the model and an adjustment of several model parameters it was possible to achieve a very good agreement between the model and the experiment for single constant-voltage BTS dependencies. For two different experimental data sets from the 45nm technology node the TDDB behavior in dependence on the bias voltage and temperature is analyzed and compared with the results of the modified Haase model and the Poole-Frenkel lifetime model.

Ultra-Low Temperature Deposition of Copper Seed Layers by PEALD

Two novel fluorine-free precursors have been developed and evaluated for use in ultra-low temperature copper deposition by PEALD. Manufacturable PEALD processes have been demonstrated, and processing conditions correlated to film composition, growth rate, resistivity and step coverage. Preliminary integration results indicate that both of these precursors have potential for use in advanced interconnect systems.

Thermal modeling of localized laser heating in multi-level interconnects

Thermal modeling was used to simulate thermal profiles from localized laser heating on two multi-level interconnect structures with metallization complexity comparable to those used in advanced interconnect systems. The modeling focused on addressing issues with regard to the effectiveness of laser-based techniques in defect localization in state-of-the-art metallization schemes. Modeling results indicate that indirect heating from the laser does not propagate effectively through adjacent metal layers from both the front side and the back side. Poor heat conduction and its associated thermal spreading during laser heating make defect detection difficult beyond three levels of metal. Thermal distribution and spreading were found to be more affected by interconnect geometries than by variations in laser spot size. Smaller temperature rises during laser heating were observed in the newer interconnect structures consisting of copper and low- k dielectric materials than in those with conventional aluminum, tungsten, and silicon dioxide. The smaller temperature rise leads to weaker signal strength at the defect sites and makes it more difficult to detect defects in the newer-material structures. Metallization density also affects heat conduction in advanced interconnect systems but the temperature rise during laser heating varies slowly as a function of metallization density.

Flip chip die attach development for multichip mechatronics power packages

New package innovations are needed to address the next generation system requirements of the automotive market. Enhanced system functionality from semiconductor components and overall cost reduction demands drive multichip package solutions. The use of semiconductor devices to switch, control and monitor high current loads will integrate logic and power devices on a common substrate with requirements for effective power dissipation, current carrying capability and fine width conductor features for the control device and interconnections. To achieve these goals Motorola's Advanced Interconnection Systems Laboratory, Munich, has developed a new package concept, a multichip mechatronics power package, utilizing flip chip die attach technology and electroplated eutectic SnPb solder bumps. With the goal to deliver an advanced package platform to cover different power levels in the system architecture,the several substrate technologies were evaluated.

Comparing migratory resistive short formation abilities of conductor systems applied in advanced interconnection systems

Various metallization types are applied in advanced high-density interconnection systems, pure metals as well as alloys, showing very different abilities for forming migration short circuit failures. There are two conventionally applied empirical possibilities for getting information or comparison about the migration behaviour of a conductor system, the water drop test, and the accelerated climatic tests, such as thermal humidity bias tests and the highly accelerated stress test. The results are generally uncertain showing large spreading and can only be interpreted with difficulties. A third method has also been developed and is presented in the paper for testing metallization systems based on a powerful technique, this is the very well-known cyclic voltammetry (CV) used in electroanalytical chemistry. The results indicate an effective method for making quick comparison between metallization systems in connection with their migration abilities. Moreover, the CV method enables a better understanding of the electrochemical processes that are the bases of the electrochemical migration.

Integration of Low Dielectric Constant Materials in Advanced Aluminum and Copper Interconnects

AbstractAdvanced on-chip interconnects using new materials and new integration architectures are necessary for current and future IC chips in order to meet the requirements in performance, reliability and manufacturing cost. Insulating materials with low dielectric constant (low-κ) and conductive materials with low-resistivity have drawn significant attention for their possible applications in IC interconnects. Dual damascene interconnect integration architectures not only offer process simplification and low cost, but also enable the use of low-resistive Cu for interconnect wiring. Use of low-κ materials in dual damascene architecture is challenging due to material and processing issues. In this paper, the evolution of advanced interconnects, materials and technology options, and some recent achievements in advanced interconnect systems of low-κ dielectric and dual damascene architectures for both Al and Cu metallization are reviewed and discussed.

Integration of Low Dielectric Constant Materials in Advanced Aluminum and Copper Interconnects

AbstractAdvanced on-chip interconnects using new materials and new integration architectures are necessary for current and future IC chips in order to meet the requirements in performance, reliability and manufacturing cost. Insulating materials with low dielectric constant (low-κ) and conductive materials with low-resistivity have drawn significant attention for their possible applications in IC interconnects. Dual damascene interconnect integration architectures not only offer process simplification and low cost, but also enable the use of low-resistive Cu for interconnect wiring. Use of low-κ materials in dual damascene architecture is challenging due to material and processing issues. In this paper, the evolution of advanced interconnects, materials and technology options, and some recent achievements in advanced interconnect systems of low-κ dielectric and dual damascene architectures for both Al and Cu metallization are reviewed and discussed.