Printing of Contact Holes for the 45nm Generation using Immersion Interference Lithography

Interference lithography is a valuable tool for evaluating photoresist performance at the resolutions unattainable with conventional exposure tools. interference lithography is most commonly used to generate one dimensional patterns such as lines and spaces. however two dimensional patterns are of much greater interest to both the resist developers and the device manufacturers in microlithography. This paper presents a technique to produce two dimensional images of contact holes at the resolution of 45nm half pitch. To our knowledge this is the highest resolution contacts printed to date using 193nm radiation. Photoresist patterns with a half-pitch of 45 nm were formed with an effective NA of 1.05 utilizing the JUT Immersion Interference system [4]. The wafer was subsequently rotated and the same pattern was printed at an angle relative to the original pattern. This double exposure technique allowed the formation of the two dimensional features. The images formed were processed, and the scanning electron micrograph (SEM) images and analysis of the data will be presented