| Popis: |
An alternating phase shift mask technique is one of the candidates to extend the KrF excimer laser lithography generation. One of the issues for practical fabrication of Alt-PSMs is a repair of quartz bump defects. A conventional focused-ion beam (FIB) repair technique has been investigated for quartz bump defect etching using (beta) -gas which has been introduced as a gas assist etching gas for MoSi based att-PSMs. We have prepared dual trench type alt- PSMs, which have programmed defects with various heights and sizes. Inspection and printability results are presented using these programmed defects masks. First, visibility of defects on a repair system is confirmed because the FIB repair system uses secondary Si ion for pattern imaging. Secondly, we have optimized parameters for quartz etching rate control with evaluation for etching depth accuracy and depth of riverbed. Thirdly, transmittance and printability of repaired point are confirmed with AIMS and wafer exposure experiments. This paper discusses feasibility of FIB repair of alt-PSMs in terms of limitation of small quartz bump defect visibility, quartz etching rate repeatability and printability of repaired points. |
