Interferometric lithography of sub‐micrometer sparse hole arrays for field‐emission display applications

Interferometric lithography, the use of interactions between coherent laser beams to define sub‐ wavelength patterns, is well adapted to the periodic nature of field‐emitter structures. Techniques to fabricate sparse (hole diameter to pitch ratio of 1:3 or larger) emitter arrays to improve reliability and lifetime are presented. These include: multiple exposures at two different pitches; integration of interferometric and optical imaging lithography; and various multiple beam techniques that both provide a sparse array and result in a two dimensional pattern in a single exposure. Moiré alignment techniques are demonstrated to provide a simple process for aligning multiple levels. Manufacturing related issues such as process latitude and photoresist profiles and their suitability for subsequent processing are also discussed. Exposure‐dose process control using latent image monitoring is demonstrated.