C. Wyon

Low-Temperature Low-Resistivity PEALD TiN Using TDMAT under Hydrogen Reducing Ambient

Titanium nitride (TiN) films were deposited using plasma-enhanced atomic layer deposition (PEALD) from the organometallic precursor tetrakis-dimethyl-amino-titanium (TDMAT) with hydrogen (H 2 ) as a coreactant. Low-resistivity values lying from 210 to 275 μΩ cm were achieved for 10 nm thick films deposited at low temperature: 150°C. The effects of temperature, plasma time, and plasma power were investigated. It was demonstrated that the chemical reaction is complementary and self-limiting. A minimum energy is necessary to reach the low-resistivity plateau. Chemical and physical properties of the films are also reported and a surface reaction mechanism is proposed. It is suggested that after TDMAT chemisorption to the surface, amines are removed by hydrogen radicals, and at the same time, titanium carbide bonds (Ti-C) are formed. The low resistivity results from the presence of Ti 2 C or Ti 2 N phases in the PEALD TiN film. The industrial viability of this process was also evaluated on 300 mm wafers. Good performances were obtained on wafer-to-wafer uniformity and step coverage, while some improvements related to the within-wafer uniformity are required.

Metrology and High Resolution Mapping of Shallow Junctions Formed by Low Energy Implant Processes

This paper presents results obtained using a Junction Photo‐Voltage (JPV) method optimized for characterization of the combined implant‐annealing process. The tool was found to be particularly suited to measurement of ultra‐shallow junction sheet resistivity and leakage. In this work the authors also evaluated the benefits of improved spatial resolution compared to previous equipment designs. Current technology USJ monitor wafers were made using a BF2 or Arsenic implant followed by a spike anneal and also R&D USJ wafers were made by Plasma Immersion followed by laser annealing. All the wafers were measured using the non‐contact JPV measurement tool. Results obtained from the JPV measurements were correlated to destructive off‐line analytical measurement tools.

Shallow junction engineering by Phosphorus and Carbon co-implantation: optimization of Carbon dose and energy

optimization of Carbon dose and energy Nathalie Cagnat, Cyrille Laviron, Daniel Mathiot, Chris Rando, Marc Juhel, Julien Singer, Frederic Salvetti, Christophe Wyon, Kelkun Duteme STMicroelectronics, 850 rue Jean Monnet, 38926 Crolles cedex, France NXP, 850 rue Jean Monnet, 38926 Crolles cedex, France Freescale, 850 rue Jean Monnet, 38926 Crolles cedex, France InESS, 23 rue du Loess, BP 20 CR, 67037 Strasbourg cedex 2, France LETI, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble cedex 9, France

In-line TEM sample preparation and wafer return strategy for rapid yield learning

Full wafer dual beam FIB-SEM systems have received a lot of industrial interest in the last years and by now are operational in several 200mm and 300mm fabs. These tools offer a 3D-physical characterization capability of defects and device structures and as such allow for more rapid yield learning and increased process control. Moreover, if SEM resolution is insufficient to reveal defect origin or the necessary process details, it is now also possible to prepare TEM samples using a controlled, easy to learn in-situ process and to efficiently continue the characterization with a high resolution TEM inspection. Thanks to latest hardware developments and the high degree of automation of this TEM sample preparation process, wafers no longer need to be broken and remain essentially free from contamination. Hence, the TEM lamella process can be considered as non-destructive and wafers may continue the fabrication process flow. In this paper we examine the SEM and TEM application capabilities offered by in-line dual beam systems. To qualify the wafer return strategy, the particle contamination generated by the system hardware as well as the process-induced contamination have been investigated. The particle levels measured are fully acceptable to adopt the wafer return strategy. Ga-contamination does exist but is sufficiently low and localized so that the wafer return strategy can be applied safely in the back-end of line process. Yield analysis has confirmed that there is no measurable impact on device yield. Although yet to be proven for the frond-end of line processes, the wafer return strategy has been demonstrated as a valuable one already in the backend of line processes. The as developed non-destructive 3-D SEM-TEM characterization capability does offer value added data that allow to determine the root cause of critical process defects in almost real-time and this for both standard (SEM) and more advanced (TEM) technologies.

Copper Surface Analysis with ToF-SIMS: Spectra Interpretation and Stability Issues

In integrated circuit manufacturing, surface cleanliness is mandatory to achieve high production volumes and device yield. Time-Of-Flight Mass Spectroscopy (ToF-SIMS) is an attractive technique for contamination control since it does provide information about both elemental and molecular species present on essentially any surface and offers high chemical sensitivity associated with sub-micrometer range spatial resolution and short acquisition time. The benefits of this technique to control surfaces after post copper chemical mechanical polishing (Cu-CMP) cleaning [1, 2] and after post via etch cleaning have already been reported.

The Role of a Physical Analysis Laboratory in a 300 mm IC Development and Manufacturing Centre

To remain competitive IC manufacturers have to accelerate the development of most advanced (CMOS) technology and to deliver high yielding products with best cycle times and at a competitive pricing. With the increase of technology complexity, also the need for physical characterization support increases, however many of the existing techniques are no longer adequate to effectively support the 65–45 nm technology node developments. New and improved techniques are definitely needed to better characterize the often marginal processes, but these should not significantly impact fabrication costs or cycle time. Hence, characterization and metrology challenges in state‐of‐the‐art IC manufacturing are both of technical and economical nature. TEM microscopy is needed for high quality, high volume analytical support but several physical and practical hurdles have to be taken. The success rate of FIB‐SEM based failure analysis drops as defects often are too small to be detected and fault isolation becomes more difficult in the nano‐scale device structures. To remain effective and efficient, SEM and OBIRCH techniques have to be improved or complemented with other more effective methods. Chemical analysis of novel materials and critical interfaces requires improvements in the field of e.g. SIMS, ToF‐SIMS. Techniques that previously were only used sporadically, like EBSD and XRD, have become a ‘must’ to properly support backend process development. At the bright side, thanks to major technical advances, techniques that previously were practiced at laboratory level only now can be used effectively for at‐line fab metrology: Voltage Contrast based defectivity control, XPS based gate dielectric metrology and XRD based control of copper metallization processes are practical examples. In this paper capabilities and shortcomings of several techniques and corresponding equipment are presented with practical illustrations of use in our Crolles facilities.

ToF‐SIMS Applications in Microelectronics: Quantification of Organic Surface Contamination

An overview of our main Time‐Of‐Flight Secondary Ion Mass Spectroscopy (ToF‐SIMS) applications is first given that highlights the strengths but also reveals some development needs for this technique especially where it comes to contaminants quantification. In this work, as a step towards better quantified data, we have elaborated a method to quantify Airborne Molecular Contamination (AMC) on Silicon. For this a protocol using liquid nitrogen sample cooling was set up to reduce the desorption of the most volatile species under the Ultra High Vacuum (UHV) of the ToF‐SIMS analysis chamber and thus to enable a more stable, reliable and representative measurement. Using this protocol for the ToF‐SIMS analysis and a careful analytical sequence, good correlation between Wafer Thermal Desorption Gas Chromatography Mass Spectroscopy (W‐TDGCMS) and ToF‐SIMS results on wafers exposed for varying time under the clean‐room air flow containing 2,2,4‐trimethyl 1,3‐pentanediol diisobutyrate (TXIB) and Phthalates — two ma...