Uniform Pressing Mechanism in Large-Area Roll-to-Roll Nanoimprint Lithography Process

Abstract

We aimed to increase the processing area of the roll-to-roll (R2R) nanoimprint lithography (NIL) process for high productivity, using a long roller. It is common for a long roller to have bending deformation, geometric errors and misalignment. This causes the non-uniformity of contact pressure between the rollers, which leads to defects such as non-uniform patterning. The non-uniformity of the contact pressure of the conventional R2R NIL system was investigated through finite element (FE) analysis and experiments in the conventional system. To solve the problem, a new large-area R2R NIL uniform pressing system with five multi-backup rollers was proposed and manufactured instead of the conventional system. As a preliminary experiment, the possibility of uniform contact pressure was confirmed by using only the pressure at both ends and one backup roller in the center. A more even contact pressure was achieved by using all five backup rollers and applying an appropriate pushing force to each backup roller. Machine learning techniques were applied to find the optimal combination of the pushing forces. In the conventional pressing process, it was confirmed that pressure deviation of the contact area occurred at a level of 44%; when the improved system was applied, pressure deviation dropped to 5%.

Nanoimprint Mold Consisting of an Adhesive Lap Joint between a Nanopatterned Metal Sleeve and a Carbon Composite Roll

“…Another conventional way to minimize deflections is to give little translational room to one side of the support (approximately 1/100th of the total length of the roller) while keeping the other support fixed. The most effective and proven approach is to use an additional supporting roller to minimize the deflections by applying a small magnitude of the force from the opposite side to that of the imprinting force [ 36 ].…”

“…The adhesive layer was evaluated using the criterion of von Mises stresses, strains, and displacement against an applied force, while the large magnitude of loading values was applied in order to check the adhesive failure limits. Parameters of deflections, applied force and pressure have been carefully selected by keeping in view the system under observation and parameters studied by similar studies [ 36 ]. Material properties of the nickel and carbon fiber adherends are listed in Table 1 and Table 2 .…”

Control of Meniscus Formation Using an Electrohydrodynamics Module in Roll-to-Roll Systems for the Stable Coating of Functional Layers

“…A span has one driven roll at the inlet and one at the outlet. As shown in Figure 1 , the driven roll is typically paired with a nip roll, which presses the web with a strong nipping pressure while rotating to transfer the web [ 29 ]. The R2R system is obtained from a configuration of several spans, as illustrated in Figure 2 .…”

Multi-Geometry Parameters Optimization of Large-Area Roll-to-Roll Nanoimprint Module Using Grey Relational Analysis and Artificial Neural Network

“…Recently, a few studies have addressed the bending problem that occurs in R2R systems when operating in a large area, and several methods have been proposed to compensate for the deformation of the roller system, such as the use of one or more additional rollers to eliminate bending [43,44]. However, these studies only deal with specific cases from the authors' research, and the results cannot be applied to many different cases, as the R2R system varies in size in terms of geometry and processing parameters.…”