| Summary: | 碩士 === 國立高雄大學 === 應用化學系碩士班 === 99 === (1)
Extreme ultraviolet (EUV) light at 13.5 nm is regarded as the most likely excitation source for microlithography processing beyond the 16 nm technology node of IC manufacturing. Outgassing from photoresists or underlayer materials upon the EUV exposure can lead to contamination of optics, which is a new issue to microlithographic applications. This work uses quadrupole mass spectrometer (QMS) and pressure rise methods to characterize and quantitatively measure outgassing.
The light source of this work is from the BL08A-LSGM beamline of NSRRC. Samples investigated include EUV model resists and PMMA (poly-methylmethacrylate) in various thickness and some confidential samples provided by two companies. Our quantitative results on outgassing are benchmarked and agree well to those reported by SEMATECH and I-institute. The benchmarking tests demonstrate that we have established an EUV outgassing evaluation system in Taiwan, which meets international standards. In addition to facility, we show that the amount of outgassing is thickness independent but EUV absorption and material structure dependent.
This work investigates ionic outgassing from novel materials of nine silicon-containing and two titanium-containing compounds. When undergone EUV irradiation, H3O+ (m/z = 19) from the silicon-containing compounds keep on increasing. The same H3O+ phenomenon are also observed for O+ and OH+ outgassing from the Ti-containing compounds are also observed. Possible mechanisms of EUV photoinduced surface bond breakage leading to H3O+ outgassing are proposed.
(2)
This work uses quadrupole mass spectrometer (QMS) to determine branching ratios and absolute photoionization cross sections in the 70-150 eV energy range for organic solvents. The samples are nine organic samples commonly used in semiconductor manufacturing. The light source is from BL08A-LSGM beamline at National Synchrotron Radiation Research Center. In order to measure absolute photoionization cross section, we calibrate QMS with a mixture of N2¬ and noble gases to obtain QMS detection sensitivity. We compare our results to those of NIST which was derived by electron impact ionization at 70 eV. Major branching ratio between both works show similar results with a difference within ±40%. This work combines the branching ratio results and thermal chemical calculation, and proposes EUV photochemical mechanisms of photoionization in 70-150 eV energy range: (1) Aromatic compounds like benzene and toluene, the production of their parent ion is the major channel. (2) Besides (1), the major reaction pathways of the solvents are direct dissociative photoionization. The order of branching ratios depends on the order of reaction endothermicity. (3) Molecular rearrangement prior dissociative photoionization is never the major channel, even if its endothermicity is relatively less. (4) The trend of bond dissociation is: C-O > C-C > C-H. In ion mass spectrum of all solvents, this work finds that the branching ratio of high mass species is getting smaller with higher energies. The results of photoionization cross section and quantum yield show that the quantum yields contain about 100% uncertainty lower than typical quantum yield. This work is primary, and more studied are needed to achieve quantitative measurements.
|
|---|
