Copper metallization in microelectronics using filtered vacuum arc deposition. Principles and technological development

Continuous efforts to further increase the performance of microelectronic circuits challenge all of the involved process modules including thin film deposition, lithographic masking and etching. Specifically, the recent trend of introducing copper as the wiring material required a change in the conventional backend process sequence that transfers the interconnect pattern. Whereas conventionally flat-deposited aluminum is masked and subsequently etched to generate metal lines, copper technology requires the filling of narrow vias and trenches etched into the dielectric interlayer. Established techniques such as thermal evaporation or sputtering have shown substantial difficulties in fully metallizing the prepared patterns. Typical failures are large voids in the volume of the resulting metal lines. In response to the requirements for next generation devices, research on plasma vapor deposition PVD processes continues to further improve film properties and reliability. During recent years, evaporation techniques that generate significantly higher ionized metal plasmas than conventional sputtering have shown their potential to suppress the formation of voids. Several pulsed magnetron sputtering methods have been investigated as possible alternatives. So far, vacuum arc plasma sources have not been considered by the suppliers of the microelectronics as an alternative although they generate the highest plasma ionization very effectively. A major concern is the deposition of microscopic droplets of the cathode material that are inevitably generated during the arc discharge. Current demands, e.g. for ultra-thin and dense carbon coatings on computer hard disks or the copper metallization in CMOS structures have stimulated new developments of more compact and higher productive filtered arc sources. In Section 1, the present paper describes the current problems of metallization in microelectronics and the needs for a higher activated PVD tech niques. Vacuum arc evaporation is introduced as a process having the potential, to solve some actual problems, provided that the droplets can be eliminated. A short historical outline of the development and current stage of filtered arc technology is given in the following. Focusing on copper metallization and barrier coatings e.g. TaN in microelectronics, the paper evaluates and summarizes the current stage of filtered arc technology achieved by groups in the USA, East Asia, Australia and Europ

Film deposition by laser-induced vacuum arc evaporation

The method of laser-induced arc evaporation (laser-arc) combines the advantages of the laser-pulse vapor deposition (LPVD) technique with the technologically utilized vacuum arc evaporation (VAD). Laser-arc may be effectively and precisely controlled like LPVD, but its energy efficiency and properties of the deposits equal those obtained by the vacuum arc. In the present paper the latest results of the study of the deposition process and the technological development of the laser-arc are presented. Studies of the influence of arc current on film deposition were carried out for different materials (Ti,TiC,C). On the basis of these results definite mutlilayered structures are prepared. As an example, a Ti/TiC multilayer system with 25-nm single layers is described. Results of structural and chemical analysis by means of AES spectroscopy are presented. It could be shown that diamond-like carbon film with a refractive index in a range of between 2.05 and 2.5 can be deposited effectively

Calculation and measurement of the time dependent erosion rate of electromagnetic steered rectangular arc cathodes

ProArc is a system for programmable electromagnetic controlling of the arc spot motion on large area flat cathodes in devices for vacuum arc evaporation. Using this system allows one to adjust predefined erosion and deposition profiles and to increase the lifetime of the cathodes. Arc spot traces and erosion profiles have been simulated for various run-modes. The simulation enables an estimation of the local erosion rate dependence on both time and magnetic field strength. The computer program used contains a model for the arc spot behavior under the influence of external magnetic fields. These calculations were compared with measured erosion profiles

Activating adherend surfaces by applying arc-discharge treatment

The demands on adhesive joints and for their long-term durability, especially under extreme environmental conditions, are steadily increasing. Most of the currently used chemical methods of adherend surface pretreatment that lead to high values of strength and ageing resistance are no longer acceptable for environmental reasons. As a possible alternative method, a pretreatment utilising the physical energy of arc discharges was studied. It was found that the strength and ageing resistance of adhesive joints prepared with the one-step arcing procedure was of the same order as, or even better than, those with the best chemical pretreatment technologies currently available. The research is continuing, with the focus on obtaining higher working speeds, optimising the procedure and its application to different materials

Characterization of carbon nitride produced by high-current vacuum arc deposition

Characterization of carbon nitride produced by high-current vacuum arc deposition / J. Hartmann ... - In: Journal of vacuum science and technology. A. 15. 1997. S. 2983-298