Resolution enhanced top anti reflective coating materials for ArF immersion lithography

Recently, a new technology called ArF immersion lithography is emerging as a main stream of next generation lithography. However, the first problem of this technology is contamination issues that come from the dissolution of contaminants from the photoresist to the immersion liquid. The second problem is defect issue that comes from interaction between immersion liquid and resist. To solve these two problems, we have developed top antireflective coating (TARC) material. This TARC material can be coated on resist without damage to the resist property. In addition, this TARC material is easily developable by conventional 2.38 wt% TMAH solution. The reflective index of this TARC is adjusted to 1.55, so it can act as an antireflective material. To this TARC material for immersion, quencher gradient resist process (QGRP) was applied also. As a result, we could improve resolution and process margin. However, some of resists showed defects that were generated by this TARC material and QGRP. To solve this defect problem, we introduced buffer function to the TARC material. Thanks to this buffer function, we could minimize defects of resist pattern in immersion lithography.