The Study Of Sub-wavelength Anti-reflection Structure Process Based On Nano-imprint Technology

Sub-wavelength anti-reflection structure is the periodic structure whose size is less or equal to the wavelength. When the wave effected on this structure, only the zero-reflection or projection wave presents. This nature of sub-wavelength structure makes the uniquely using in many aspects applications, such as the harsh environment anti-reflection used in military, while it cannot achieve the desired requirement when using the traditional anti-reflection film. The sub-wavelength structure anti-reflection effect is better than the traditional anti-reflective film in general civilian using too, one of the advantages is the durable using when compared each other. These makes the sub-wavelength structure becomes the hot research area. There are many ways to produce this structure. The nano-imprint based technology of processing is researched in this paper for produce. This technology is seen as a representative of the next generation lithography, and the alternative technology of the microelectronics technology which has reached the limit of optical exposure.In this paper, the finite element simulation software is used to simulate the process of the photo-resist filling into the gap of template in nano-imprint process. The model is established for the simulation. The fluid surface tension and contact angle are added to consider, the template period, the duty cycle, the aspect ratio are considered when analyzing the pattern transfer effects and the polymer filling uniformity issues. We find that, in nano-scale, the template owning the large periodic, high duty cycle enjoys better polymer filling quality, while the template owning the small periodic, small duty cycle and high aspect ratio is not easy for the polymer filling. When simulation the non-periodic structure, the template with different groove width enjoys different filling rate, the smaller the template groove has the lower the polymer filling into the groove. If the groove width changes significantly of one template will make the polymer filling difficult, resulting the default. The non-uniformity will be observed during the simulation when the period is less than 400nm of the template which possesses the fill factor f=0.5 and the aspect ratio r=1. Then, the influence of the fill factor and the aspect ratio on the uniformity is researched, and the non-uniformity is observed during the simulation when the fill factor is less than 0.3 or the aspect ratio is more than 1.67 for the template whose period is less than 1000nm. The research can be prepared to provide the basis for the preparation of template.The single-step and double-step of sub-wavelength anti-reflective structure which are based on quartz substrate is designed by EMT theory. And this structure's reflectivity is calculated by DiffractMod. The contrast is made between the EMT and RCWA method calculation, which meet together reflecting the correctness of the design. The single-step and double-step structure are transferred on the quartz substrate using the nano-imprint and RIE processing. The RIE divided into two steps, the first step is using O2 etching the residue photo-resist after the nano-imprint, the second step is using SF6 etching the substrate. It is been proved that the 40sccm of O2 and 20sccm of SF6 is the best experiment condition. The oxygen pressure: 20mTorr, RF power: 20W. The SF6 pressure: 60mTorr, RF power: 40W. After etching the substrate measured the reflectivity, and software simulation results is compared to determine the reliability of process steps.