Journal of Vacuum Science & Technology B, Vol.20, No.6, 2634-2639, 2002
Direct measurement of chromatic aberrations induced by SiNx continuous membrane mask
In this article, we present experimental results that quantify the magnitude of chromatic aberrations induced by a SiNx continuous membrane mask. We used a continuous membrane. mask, which consists of a TaSi scatterer layer on a SiNx membrane layer of 100 nm thickness, for the experiments. The beam edge profiles were measured directly by the knife-edge method, which can measure the image blur with the repeatability of 3 nm (3 sigma). The effect of electron energy loss induced by inelastic scattering is clearly shown in the measured beam edge profiles. The magnitude of chromatic aberrations is quantified from the measured beam edge profiles considering lens aberrations and measurement errors. The results show that lower atomic number Z and lower density materials and thinner membrane are required on the mask membrane for a high resolution lithography.