Investigation of fundamental mechanisms of pore and network formation in mesoporous low-k dielectrics by combining spectroscopic techniques

• Applicants: Professor Dr.-Ing. Stefan E. Schulz; Dr. Andreas Wagner
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering ; Synthesis and Properties of Functional Materials
• Term: from 2018 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 398216953

Porous organosilicates have been widely used for the metallization of integrated circuits in leading edge technology for over 10 years. Nevertheless, in literature, there are still open questions concerning the formation and variation of the porous structure. The aim of this project is to investigate fundamental formulations of questions about the kinetic and physical processes in porous low-k dielectric material during the curing process. The following questions will be investigated time-depended and in situ.- Which impact has the temperature on cross-linking and porogen extraction in detail?- How is the time-depended development of pores and network?- Is there a mutual interference between these two processes?- How does the process pressure influence cross-linking and porogen extraction?- Are lower temperatures useful during UV curing?- Does material damage occur during the curing process?- How does the curing process depend on porogen concentration?- How do different network materials influence the curing process?- Can spin-on ULK dielectrics be cured the same way like CVD ULKs? There is currently no difference in the literature. However, both materials could not be more different.Two different spectroscopic methods will be used to study the fundamental kinetic and physical processes of porous network formation in ultra low-k dielectrics. At the Chemnitz University of Technology, the time-dependent analysis of the network will be investigated in an experimental curing chamber with an integrated FTIR measuring system. At the Helmholtz Zentrum Rossendorf the in-situ characterization of the pore system will be done by positron annihilation spectroscopy. The two available EPOS and SPONSOR sources (AIDA I and AIDA II) are used for this purpose. By means of the pulsed positron source (EPOS), which is unique worldwide, depth-dependent material investigations can be carried out during the curing process. Associated with this, the mechanical and electrical properties will be determined in order to represent their linkage to the pore and network parameters and to place them into existing literature. With the closing of the experimental investigations, FEM simulations will support the results.

• DFG Programme: Research Grants