Electrical plasma diagnostics for the measurement of ion related parameters at the substrate surface

Abstract

As the semiconductor industries are advancing towards atomic scale dimensions, the knowledge of ion related parameters is becoming critical while developing highly advanced plasma etch and deposition processes. This thesis presents novel plasma diagnostic techniques to measure ion related parameters at the wafer surface. These techniques based on retarding field analyzer adds important functionality to this sensing technology and can provide useful insight which is intensely desired to meet the future needs of nano-manufacturing industries. Plasma spatial profile in terms of ion energy and ion flux, ion angular distribution and ionized flux fraction are crucial parameters which can greatly influence ion enhanced plasma deposition and etch processes for the fabrication of next generations of sub - 10 nanometre integrated circuits. Ion related parameters measured in the bulk of the plasma may not precisely predict on how ions will interact at the surface of the substrate. Planar retarding potential analyzer is the most appropriate diagnostic which measures ion related parameters exactly on the surface of the substrate. In this thesis, we have demonstrated various possible methods with appropriate modifications in the existing sensor design toimprove its measurement functionality and subsequently help semiconductor industry develop tightly controlled plasma processes to achieve smallest possible feature size that can be created in the wafer. The work in this thesis focuses on the measurement of a number of ion related parameters to investigate a variety of plasma assisted processes using newly developed techniques and modified designs of the sensor. The modified geometries associated with novel techniques are useful extensions to this sensing technology which makes it an attractive plasma diagnostic suitable to achieve the future needs. The main findings of this thesis concludes that measurement of ion related parameters at the location of the wafer surface using novel sensor design and techniques can provide useful means to process engineers in developing and control highly precise plasma processes