A novel simple sub-15nm line-and-space patterning process flow using directed self-assembly technology

A Simulation Study on Defectivity in Directed Self-assembly Lithography

“…In this work, we have investigated the generation mechanisms of the grid defects observed in the COOL process [10][11][12][13][14]. We modeled the COOL process using the SCFT.…”

“…As discussed in the references [10][11][12][13][14], the grid defects appeared differently depending on the annealing time and annealing temperature, and so their origin may be related with the metastable morphologies. Therefore, we have explored the metastable states by the free energy analysis method [23,24].…”

“…Many applications such as hole shrink [1][2][3][4][5] and line/space (L/S) patterning for FinFET device [6] have been reported in recent years. In the L/S applications, some prospective process flows such as the lift-off process [7], the LiNe process [8], the SMART TM process [9], and the coordinated line epitaxy (COOL) process [10][11][12][13][14] have been demonstrated in full-wafer experiments. These demonstrations manifested that defects constituted one of the most important obstacles concerning practical applications of the DSA lithography.…”

“…In our recent studies [10][11][12][13][14], we have investigated grid defects, which are considered to be a kind of hexagonally perforated lamellar (HPL) metastable phase, as one of the characteristic pattern defects in the coordinated line epitaxy (COOL) DSA lithography process using polystyrene-block-poly(methyl methacrylate) (PSb-PMMA). Since the grid defects observed in the COOL process, as shown in Fig.…”

“…1 (a), appeared a quasi-hexagonal arrangement on the neutral layer after the PMMA block removal, they looked like the HPL phase extensively observed as a long-lived metastable phase in bulk systems [16,17]. Although the details of the grid defects have been intensively investigated by use of the small-angle X-ray scattering method (SAXS) [18], helium ion microscopy (HIM) [19], and conventional secondary electron microscopy (SEM) [10][11][12][13][14]20], the origin of the defects has yet to be clarified. In this work, we report on the generation mechanisms of the grid defects, presenting findings obtained using a simulation method based on self-consistent mean field theory (SCFT) [21].…”