EXPOSURE LATITUDE AND CD CONTROL STUDY FOR ADDITIVELY PATTERNED X-RAYMASK WITH GBIT DRAM COMPLEXITY

40 kV electron beam lithography has been used to pattern gold plated x -ray masks containing GBit DRAM complexity layouts. The two commercial e-beam resists used, namely PMMA and SAL 601, both showed 0.12 mu m r esolution capability in dense and large layouts patterning and also, u nder optimised exposure and development conditions, exhibited good exp osure latitudes which were also evaluated for two different beam spot sizes. Furthermore, a study of development technique and effect of e-b eam spot size indicated a marked dependence of ultimate resolution and exposure latitude on such parameters. A statistical analysis of 0.12 mu m resolution SAL patterning on large chip dies (30 x 30 mm(2)) resu lted in a dimensional control of 10 nm (3 sigma value).