Study Of Compressional Gas Cushion Press Nanoimprint Lithography

With the boost and development of Large Scale Integrated circuit(LSI), the integration is getting higher and the minimum feature size is shrinking sharply. The resolution of traditional optics lithography technology is becoming limited to kinds of optical effects,e.g.,the effect of light diffraction, interference of light, reflection of light on the substrate, the choice of short wavelength light source, which have become technical obstacles of traditional optics lithography for further application in the smaller nodes. Traditional lithography technology has reached the technical limit, the next generation lithography technology with higher resolution needs to be proposed and developed urgently. Nanoimprint lithography(NIL) has continuously received attention and praise for its simple process, high resolution, good fidelity, low cost and high output since it was proposed in1995by Steven. Y Chou. It has been included in ITRS2003as one of NGL(Next Generation Lithography) for32nm node, and the highest resolution has reached5nm.The major research in NIL field is focused on the continuous improvement of the technology itself and its innovative application based on NIL. This paper firstly introduce the three main technology of NIL, then introduce various novel variants of technology based on traditional NIL, selection of the templates, pressing methods, and technology advantages and disadvantages are also analyzed.This paper proposed CGCPN(Compressional Gas Cushion Press Nanoimprint Lithography) based on the existing ACP(Air Cushion Press). The simulations of FEM software Comsol Multiphysics and analysis of the results prove that CGCPN can achieve more uniform pressure distribution on the mold than ACP, which could avoid damage to the mold arising from the airflow disturbance effectively in the early air inflation stage and in favor of prolonging the life of the mold. In order to avoid air bubble defect in process of pressuring, a simple protective measure,i.e., prominent O-ring design on the mold was put forward. The mechanical analysis and discussion of the fluid transfer layer indicate that the effective widths of O-ring which meet the requirements of parameters could resist the entrapment of air bubbles and avoid air bubble defect. In the process of NIL, the uniformity of demolding force determines the integrity and the fidelity of duplicated patterns in resist. A novel electrostatic repulsion assisted demolding method based on the suspended slider was proposed and studied. This method with no need for a prefabricated metal conductive layer on the mold, utilizes the electrostatic repulsion between plate electrode and metal nanoparticle film or metal film directly separates the mold and the substrate. The analysis proved that this novel demolding method could achieve more uniform demolding force which could meet the demand of demolding and ensure the integrity and the fidelity of patterns.