This work discusses the requirements and performance of Honeywell's middle layer material, UVAS, for tri-layer
patterning. UVAS is a high Si content polymer synthesized directly from Si containing starting monomer components.
The monomers are selected to produce a film that meets the requirements as a middle layer for tri-layer patterning (TLP)
and gives us a level of flexibility to adjust the properties of the film to meet the customer's specific photoresist and
patterning requirements. Results of simulations of the substrate reflectance versus numerical aperture, UVAS thickness,
and under layer film are presented. ArF photoresist line profiles and process latitude versus UVAS bake at temperatures
as low as 150ºC are presented and discussed. Immersion lithographic patterning of ArF photoresist line space and contact
hole features will be presented. A sequence of SEM images detailing the plasma etch transfer of line space photoresist
features through the middle and under layer films comprising the TLP film stack will be presented. Excellent etch
selectivity between the UVAS and the organic under layer film exists as no edge erosion or faceting is observed as a
result of the etch process. A detailed study of the impact of a PGMEA solvent photoresist rework process on the
lithographic process window of a TLP film stack was performed with the results indicating that no degradation to the
UVAS film occurs.
Physical properties and alignment performance of biphenyl and terphenyl negative dielectric anisotropic liquid crystal (LC) compounds are investigated. Results show biphenyl compounds align well in homeotropic LC cells and the alignment of terphenyls are relatively poor. We have developed a new method to align these high birefringence LC compounds. Adding a few percent of positive dielectric anisotropic or nonpolar LC material not only enhances the contrast ratio but also improves the overall figure-of-merit. Molecular modeling and experimentation are demonstrated to support this concept.
We have developed a non-contact birefringence probing method for studying the dielectric heating-induced temperature rise of dual-frequency liquid crystals (DFLCs). The dielectric heating effects of three DFLC mixtures are investigated quantitatively. By properly choosing the molecular structures, the dielectric heating effect can be minimized while keeping other desirable physical properties uncompromised.