| AVS 65th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Wednesday Sessions |
| Session PS+EM-WeA |
| Session: | Advanced BEOL/Interconnect Etching |
| Presenter: | Gyanendra Bhattarai, University of Missouri-Kansas City |
| Authors: | G. Bhattarai, University of Missouri-Kansas City S. Dhungana, University of Missouri-Kansas City B.J. Nordell, University of Missouri-Kansas City A.N. Caruso, University of Missouri-Kansas City M.M. Paquette, University of Missouri-Kansas City W. Lanford, University at Albany S.W. King, Intel Corporation |
| Correspondent: | Click to Email |
In order for self-aligned multi-pattern techniques to be extended deep into the single digit nanometer range, new fab friendly material combinations with near perfect etch selectivity will need to be identified. This in turn requires a greater understanding of the interplay between plasma etching processes and the properties of the material being etched. While some qualitative correlations between dry etch rates and material properties such as composition, porosity, and density have been reported, more quantitative relationships have been generally lacking. In this regard, we demonstrate that analytical expressions derived to describe the material dependence of the yield for ion-induced sputter processes can be extended to reactive ion etch processes. Specifically, we first demonstrate a direct relationship between the atomic surface binding energy (Usb,), bulk modulus, and ion sputter yield for the elements, and then subsequently prove our hypothesis for amorphous multi-element compounds by demonstrating that the same relationships exist between the reactive ion etch (RIE) rate and nanoindentation Young’s modulus for a series of a-SiNx:H and a-SiOxCy:H thin films. The impact of a materials network topology is further revealed via application of the Phillips–Thorpe theory of topological constraints, which directly relates Young’s modulus to the mean atomic coordination (<r> ) for an amorphous solid. The combined analysis allows the observed trends and plateaus in the RIE rate versus modulus to be ultimately reinterpreted in terms of the atomic structure of the target material through consideration of <r> . These findings establish the important underlying role of mechanical rigidity and network topology in ion–solid interactions and provide a new consideration for the design and optimization materials for self-aligned pitch division / multi-pattern technologies.