Pattern placement correction methodology for 200 mm SCALPEL masks

Methods for correcting pattern placement errors found on SCALPEL™ masks are addressed. The methodology and implementation of individual membrane image placement correction is presented, showing its advantages over the global image placement correction method. Local image placement corrections are possible by the unique capability of electron projection lithography (EPL) tools to correct placement errors with electron optical components during exposure while addressing each individual mask membrane. Data of pattern placement on a series of 200 mm SCALPEL masks from different sources was collected. Within the mask set and patterning tools used, the placement errors are similar for all masks regardless of source. Local image placement corrections can reduce placement errors to less than 14 nm, which is less than the 20 nm budget allocated for 100 nm node lithography. Implementation of local image placement correction will permit EPL lithography to be ready for sub-100 nm node lithography without the need to burden existing mask writers on severely stringent pattern placement tolerances or chucking procedures. © 2001 American Vacuum Society.