Second level printing of advanced phase shift masks using DUV laser lithography

Laser lithography tools have been a staple in the photomask industry for second level printing for several years. This paper explores the overlay capabilities of the Alta4300D Deep UV (DUV) lithography system. The tool is manufactured by ETEC Systems, a part of the Mask Business Group of Applied Materials. The tool demonstrates good overlay performance, and an improved data path ensures the ability to handle large file sizes without an adverse impact on writing time. In addition to actual performance data on product masks, a simple analysis of the maximum total edge placement error of a hypothetical two level alt-PSM process is presented. The results show the tool is capable for many advanced phase shift overlay applications.