Projection mask-less lithography (PML2): First results from the multi beam blanking demonstrator

A proof-of-concept multi beam blanking device (“blanking demonstrator”) has been fabricated for the projection mask-less lithography project. It comprises a Si chip with approx. 4000 openings (each has a size of 8×8μm2) etched through with adjacent blanking electrodes fabricated by electroplating. The parameters of the blanking demonstrator such as electrode layout and density of openings are identical to the blanking device of the final production tool. The demonstrator is being tested within a dedicated broad beam electron beam teststand, which has proven to resolve <2μrad angular deviation. First experiments with the demonstrator showed a blanking sensitivity of 145–165μrad/V which is best suited for the driving voltage of CMOS circuits. Cross talk through individual switching of nearest neighbor openings has been determined to be <(1.3±0.1)μrad/V electrode potential. This is well below the cross talk target specified for 45nm node lithography.