Progress in Placement Control for Ion Beam Stencil Mask Technology

摘要

Stencil masks, based on 150mm Si-wafers, with large diameter membrane fields have been fabricated for use in an ion projection lithography (IPL) tool. With a current membrane diameter of 126mm, the control of pattern placement is one of the major challenges. As the masks are produced by a wafer flow process, pattern distortions after membrane etch, caused by stiffness changes, have to be controlled. Additionally, stress inhomogeneity resulting from SOI wafer blank fabrication, boron implantation and other process steps have to be addressed. These parameters will be discussed on a global and local scale. Results by both, experiments and FE modeling simulations are presented.