Mask-Membrane Impact on Image Blur in SCALPEL

The SCALPEL imaging technique utilizes the difference in elastic scattering properties of the patterned layer of the mask and the supporting membrane irradiated by the flux of energetic (100 keV) electrons. A membrane mask has an obvious advantage over a stencil scattering mask because closed features can be formed on the membrane. This eliminates the need for a complementary mask set and a second alignment that would be an additional source for placement error. As a result, the exposure and overhead times are significantly less for membrane masks.