Advanced CD-SEM metrology for pattern roughness and local placement of lamellar DSA

Abstract

Directed self-assembly (DSA) applying chemical epitaxy is one of the promising lithographic solutions for next generation semiconductor device manufacturing. We introduced Fingerprint Edge Roughness (FER) as an index to evaluate edge roughness of non-guided lamella finger print pattern, and found its correlation with the Line Edge Roughness (LER) of the lines assembled on the chemical guiding patterns. In this work, we have evaluated both FER and LER at each process steps of the LiNe DSA flow utilizing PS-b-PMMA block copolymers (BCP) assembled on chemical template wafers fabricated with Focus Exposure Matrix (FEM). As a result, we found the followings. (1) Line widths and space distances of the DSA patterns slightly differ to each other depending on their relative position against the chemical guide patterns. Appropriate condition that all lines are in the same dimensions exists, but the condition is not always same for the spaces. (2) LER and LWR (Line Width Roughness) of DSA patterns neither depend on width nor LER of the guide patterns. (3) LWR of DSA patterns are proportional to the width roughness of fingerprint pattern. (4) FER is influenced not only by the BCP formulation, but also by its film thickness. We introduced new methods to optimize the BCP formulation and process conditions by using FER measurement and local CD valuation measurement. <br/> <br/> Publisher’s Note: This paper, originally published on 2 April 2014, was replaced with a corrected/revised version on 14 May 2014. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance.