Euler-Bernoulli bending theory applied to high NA EUV dense line-space patterning to characterize the line wiggling

Abstract

Background Dimensional scaling of line features can lead to line wiggling after development and after the etching process step. The line wiggle (WGL) phenomenon is strongly influenced by the process conditions and by the film stack, due to both thickness and stiffness of the materials involved.

Aim We aim to understand the relationship between critical dimensional (CD) and line wiggle, which is essential to identifying material, process, and stack requirements that can minimize the WGL as the CD scales down.

Approach The impact of resist properties, development process, and film stack properties online wiggle is investigated by applying the Euler–Bernoulli bending theory to sub-10 nm lines, after development and after etch.

Results WGL is mainly driven by mechanical properties of the patterned line features, such as (i) aspect ratio, (ii) material stiffness (Young’s modulus), and (iii) etching-induced forces.

Conclusions Investigating and optimizing material mechanical properties, stack engineering, and etching is crucial to minimizing the WGL phenomenon in high NA EUV patterning as severe line wiggles can lead to line collapse with consequently low electrical device yield.