Significant progresses on 300 mm wafer level DSA (Directed Self-Assembly) performance stability and pattern quality were demonstrated in recent years. DSA technology is now widely regarded as a leading complementary patterning technique for future node integrated circuit (IC) device manufacturing. We first published SMARTTM DSA flow in 2012. In 2013, we demonstrated that SMARTTM DSA pattern quality is comparable to that generated using traditional multiple patterning technique for pattern uniformity on a 300 mm wafer. In addition, we also demonstrated that less than 1.5 nm/3σ LER (line edge roughness) for 16 nm half pitch DSA line/space pattern is achievable through SMARTTM DSA process. In this publication, we will report impacts on SMARTTM DSA performances of key pre-pattern features and processing conditions. 300mm wafer performance process window, CD uniformity and pattern LER/LWR after etching transfer into carbon-hard mask will be discussed as well.
Proc. SPIE. 9050, Metrology, Inspection, and Process Control for Microlithography XXVIII
KEYWORDS: Etching, Process control, Finite element methods, Line width roughness, Directed self assembly, Chemical analysis, Critical dimension metrology, Line edge roughness, Semiconducting wafers, Edge roughness
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.
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