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Electron projection lithography mask format layer stress measurement and simulation of pattern transfer distortion J. Vac. Sci. Technol. B 20, 3053 (2002); 10.1116/1.1521732Patterning-induced image placement distortions on electron beam projection lithography membrane masks Low-energy electron projection lithography (LEEPL) is a candidate for next generation lithography and thus the 1ϫ LEEPL mask requires a stringent local image placement (IP) error budget. Applying a doping method with silicon-on-insulator substrates, 700-nm-thick membranes were investigated for stress control and in-plane distortion (IPD), which are the main contributors to local IP errors. Stress control results show that at a dopant concentration of 6.74ϫ 10 19 /cm 3 , the membrane stress in a 10 mm test structure is 8.4 MPa. Also stress variation is excellent at 0.3 MPa across a 200 mm complementary stencil mask on support strut-type LEEPL mask. The IPD results indicate that small membrane window size, low void fraction, as well as low membrane stress is the proper strategy to allow a stencil mask with dense stencil patterns to meet required IPD. Additionally, the local IP errors of large scale integrated 90 nm hole pattern were demonstrated.

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