Printing sub-100 nm random-logic patterns using binary masks and synthetic-aperture lithography (SAL)

Synthetic-aperture lithography (SAL) is proposed as a means for reaching design-rules of 0.1 mu m and below. By a combination of oblique illumination and pupil filtering the relation between high and low spatial frequencies in the image is altered. Simulations indicate that random-logic patterns can be printed at k(1) = 0.40 with only modest OPC. With some design constraints and/or a corrective auxiliary exposure k(1) = 0.32 is possible. The main disadvantages are a complex stepper design and low light transmission, the advantages are the use of standard binary masks and good useful resolution.