New tri-level structures for submicron photolithography

New tri-level resist structures for photolithography have been developed for volume VLSI production with submicron geometries. Organosilica film is used as an intermediate layer. This film can be formed by spin-coating process and has a sufficient tolerance for O2reactive sputter etching. Both standing waves in top layer and linewidth variation on substrate steps are prevented by incorporating absorption dye into an organosilica intermediate layer. The complex refractive index for organosilica with absorption dye was measured, and the absorbed energy profile inside the top layer resist was simulated. Excellent properties in the present technology are proved by the simulation.