Advanced KrF chemical amplified photoresists for 0.13-μm lithography

When critical dimension shrinks down to 0.12micrometers , lithography patterning becomes one of the major issues: limited process window, line edge roughness, CD error budget, and challenges on mask technology. Concurrently, 248nm and 193nm DUV lithography strategies are developed. However, with much concerns on 193nm lithography resists and exposure tool, 248nm lithography shows some advantages in availability of high er NA (0.7~0.8) tool, advanced resists and resolution enhancement technologies such as off-axis illumination, OPC and PSM technology. In this paper, we report development works done on 0.13micrometers gate patterning with 248nm advanced chemical amplified photoresists (CAR) annular illumination, OPC and half-tone PSM technology. The study shows that with newly development work on advanced 248nm photoresists, the process window can be enlarged to 0.60micrometers overlapping on both 0.12micrometers isolated and dense lines. Different formula impact greatly on resist profile, resist top loss and process latitudes. Annular illumination improves process latitudes, however bigger iso-dense bias is observed. Hence, OPC correction on iso-dense bias is very effective in this case. A 6% half tone PSM mask is used to improve resolution and process window in the study.