Doctoral research project

Person in charge of the project:
CLAEYS CORNEEL, member of research team Associated Section of ESAT - INSYS, Integrated Systems
Development of a Novel Metal-Insulator-Semiconductor Planar Capacitor Test Structure and Its Applications in Cu Interconnect Research
Project summary:
Copper interconnect scaling is becoming more and more challenging for each new technology node. There are many technical issues which could potentially limit the further scaling of Cu interconnects in the future. One of such issues is the degradation of the time dependant dielectric breakdown (TDDB) associated with the scaling. Therefore, it is of paramount importance to understand the limitations of interconnect scaling based on intrinsic TDDB properties of Cu interconnects. However, conventional damascene structures for TDDB testing do not offer the capability to measure intrinsic TDDB properties. One of the key focuses of this thesis is to develop a novel test structure to study intrinsic TDDB properties of various configurations in Cu interconnect systems. A planar capacitor test structure based on metal-insulator-semiconductor design was developed to provide such capability. This so-called Pcap test structure showedexcellent area scaling in capacitance, leakage current, and TDDB lifetime. The Pcap test structure was applied to understand many fundamental aspects of interconnect TDDB. It was demonstrated that TDDB lifetime followed the 1/E dependence in a configuration where Cu was involved in the breakdown. In contrast, power-law or √E dependence was observed for TDDB lifetime in another configuration when Cu was not involved. Therefore, adirect correlation between TDDB lifetime model and failure mechanism was established. The Pcap teststructure was also used to study many important areas of interconnect scaling. More specifically, the impacts of dielectric spacing, porosity of low-k dielectrics, and new dielectric barriers on intrinsic TDDB were investigated. The results provide further understanding of interconnect TDDB. Another great benefit of the Pcap test structure is its unique capability to measure capacitance of dielectric films after a metal barrier is deposited on top of the dielectric films. This leads to the realization of quantification of low-kdamage induced by metal barrier depositions. Systematic study of low-k damage induced by metal barrier depositions was performed.
ph.D student :
Lie Zhao
Faculty of Engineering Science
Doctoral Programme in Engineering (Leuven)

ph.D defence : 21.08.2012
Full text ph.D


Project number:

Duration of the project:
30.06.2010 - 21.08.2012

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