Preliminary investigation of shot noise, dose, and focus latitude for e-beam direct write

Maskless electron beam lithography can potentially extend semiconductor manufacturing to the 10 nm logic (16 nm half pitch) technology node and beyond. KLA-Tencor is developing Reflective Electron Beam Lithography (REBL) technology targeting high-volume 10 nm logic performance. There are several potential applications for E-Beam Direct Write Lithography in high volume manufacturing (HVM) Lithography. They range from writing full critical layers to the use as complementary lithography in order to write cut masks for multiple patterning optical lithography. Two of the potential applications for REBL with specific requirements on the writing strategy are contact layer and cut mask lithography. For these two applications the number of electrons writing a single feature can be a concern if the resist sensitivity is high and the process latitude is small. This paper will share calculations with respect to the needed and expected shot noise, dose and focus latitude performance of a proposed REBL lithography system. The simulated results will be compared to data taken on test structures. Predicted performance based on the simulations and test results of a potential REBL system for contact layers and cut mask applications will be discussed.