Stencil Mask Technology for Sub-0.18-Micrometer Lithography

A program is proposed to identify the stencil mask technology necessary for fabricating sub-0.18-micrometer integrated circuits by projection lithography. This proposal addresses the essential elements of a theoretical and experimental investigation of critical material and fabrication issues related to stencil masks leading to a Phase II proof-of-concept demonstration of the practical feasibility of stencil mask technology. A comprehensive survey of stencil mask materials and process technologies will be made. Key issues will be modeled theoretically; they include pattern distortion, mask temperature, complementary pattern techniques, and feature wall angles. Three issues will be studied experimentally to verify proofs of concept. The first is in the area of new membrane materials suitable for ion masks. The second is in the selection, availability, and bondability of new, stiffer frames. The third is in the demonstration of high lifetime of ion masks fabricated from new materials. The final task of the program is to bring together the survey and the theoretical and experimental studies and then select the materials and processes to be used in a Phase II mask technology demonstration of stable, low-distortion, and high-pattern-density stencil masks. Anticipated Benefits/Potential Applications - The development of a technology for fabricating stable, low-distortion stencil masks is expected to help create strong c(xiottercial interest for projection lithography and firmly establish a leadership position for the U.S. in projection lithography mask-making for sub-0.18-micrometer integrated circuits, such as 1 Gbit DRAMS, as well as quantum devices, integrated optical devices, and other nanostructures.