Novel resist material for sub-100-nm contact hole pattern

Abstract

Thermal flow process using a novel resist called the SMART (SaMsung Advanced Resist for Thermal flow process) was studied. The SMART consists of the conventional polyhydroxystyrene-based polymers and the additives inducing thermal cross-linking reactions with the base polymers. With the SMART resist, 240 nm contact holes were defined by KrF lithography system. Then following one-step thermal flow resulted in down to 90 nm contact holes with vertical sidewall profile. At 90 nm resolution, the critical dimension (CD) variation on 200 mm wafer was less than 20 nm. Its etch selectivity to silicon oxide was improved due to the cross- linking reaction. The main feature of the SMART is one step process having the linear dependency of flow rate on baking temperature. The flow amount can be controlled within the range of 100 - 150 nm without any significant pattern deformation. The thermal flow process using the SMART is a promising candidate for the fabrication of gigabit devices.