A new thermo resist enhanced optical lithography (TREOL) technique is proposed. Numerical simulation was performed on the TREOL. The TREOL offer the possibility of greatly enhanced resoluion and process window. The TREOL uses a thermo-resist instead of photoresist taking advantage of a nonlinear superposition effect. The nonlinear superposition utilizes the fact that thermo-resists do not follow the reciprocity law. This phenomena allows to separate a complex image into simple subsets which are imaged onto the same die. This concept will realize a fabrication of 1 features with existing steppers and without and proximity effects. Hopkin's fourdimensional integral is used for calculation of the diffraction intensity of projection image. Intensity of impressed heat flux is assumed to be proportional to the intensity of this diffraction image. Transient heat transfer in wafer and layer of thermo-resist is analyzed by non-linear 3 dimensional finite element method. The numerical result demonstrates an drastic improvement in resolution and process window.

No abstract