Electron scattering phenomena, occuring in the pattering of tungsten/carbon reflection-masks for X-ray projection lithography, are theoretically investigated. A bi-layer resist subtractive process is analysed by Monte Carlo simulation and proximity-effect evaluation. Results are utilised in order to calculate resist development profiles. Electron-beam energy (20 to 100 keV), mask substrate material (silicon and diamond) and pattern density are considered as process variables. In the presence of a bulk substrate, the better intrinsic scattering characteristics of diamond, with respect to silicon, result in higher-contrast patterns starting from intermediate energies. Only minor improvements are obtained by going to the higher electron energies. A resolution of 0.25 μm is achieved at 50 keV with bulk-diamond substrates. The use of a membrane, allowed by the favourable mechanical properties of diamond, is proposed in order to improve resolution during the lithographic stage of the mask-fabrication process. A resolution of 0.15 μm is demonstrated at 75 keV with diamond supporting membranes.
The role of electron scattering in x-ray reflection-masks / Messina, G; Paoletti, A.; Santangelo, S.; Tucciarone, A.. - In: MICROELECTRONIC ENGINEERING. - ISSN 0167-9317. - 26:1(1994), pp. 49-61. [10.1016/0167-9317(94)90044-2]
The role of electron scattering in x-ray reflection-masks
MESSINA G;S. SANTANGELO;
1994-01-01
Abstract
Electron scattering phenomena, occuring in the pattering of tungsten/carbon reflection-masks for X-ray projection lithography, are theoretically investigated. A bi-layer resist subtractive process is analysed by Monte Carlo simulation and proximity-effect evaluation. Results are utilised in order to calculate resist development profiles. Electron-beam energy (20 to 100 keV), mask substrate material (silicon and diamond) and pattern density are considered as process variables. In the presence of a bulk substrate, the better intrinsic scattering characteristics of diamond, with respect to silicon, result in higher-contrast patterns starting from intermediate energies. Only minor improvements are obtained by going to the higher electron energies. A resolution of 0.25 μm is achieved at 50 keV with bulk-diamond substrates. The use of a membrane, allowed by the favourable mechanical properties of diamond, is proposed in order to improve resolution during the lithographic stage of the mask-fabrication process. A resolution of 0.15 μm is demonstrated at 75 keV with diamond supporting membranes.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
