Proximity effect (electron beam lithography)

About: Proximity effect (electron beam lithography) is a research topic. Over the lifetime, 940 publications have been published within this topic receiving 8508 citations.

A comprehensive model for sub-10 nm electron-beam patterning through the short-time and cold development.

Abstract: In this study, we propose a set of single-spot experiment to construct a comprehensive model of electron-beam lithography to describe the relation among the incident electrons, resist, and the development conditions such as durations and temperatures. Through the experiments, small feature can be achieved by performing a short-time development due to the high acceleration voltage and large depth of focus of electron-beam system. The singular point in the beginning of the development is also observed in our model and supported by the experimental data. In addition, we verify the characteristic region of each incident spot induced by the point spread function of the electron-beam system. We further fabricate the single line with narrow groove width by utilizing the results from single-spot experiment at low developing temperatures. The line is formed by arranging a series of incident points with a distance close to the characteristic radius. This method can eliminate the proximity effect effectively and thus the groove width is scaled down to 8 nm. By adopting the successful experience in the single line formation, dense array with narrow linewidth is also demonstrated under well suppression of the proximity effect. The minimum groove width of 9 nm with 30 nm pitch is achieved with 5 s development time at -10 °C. Finally, the exceptional capability of pattern transfer is presented due to the high aspect ratio of the resist.

Electron-beam lithography simulation for EUV mask applications

Abstract: Extreme-ultraviolet-(EUV) mask fabrication using electron-beam lithography has to eliminate the proximity effect defects, for the accurate representation of the patterned features. One special characteristic of EUV masks is that they contain a multilayer stack of repeated Si/Mo thin layers. This has to be considered explicitly in the simulation of electron-beam energy dissipation calculation using Monte Carlo methods. In a first approximation to the problem of electron scattering in a multi-layer substrate, the continuous slowing down approximation utilizing the Rutherford differential cross section is used in order to describe the electron inelastic energy loss mechanism and determine the amount of deposited backscattered energy, in the resist film on top of the multi-layer substrate. Three-dimensional modeling is used and in this first attempt to describe the process, no secondary electron generation or other excitation processes are considered. The effect of the number of layers and their relative thickness in terms of incident electron energy is investigated.

Investigation of proximity effect correction in electron projection lithography (EPL)

Abstract: An electron projection lithography (EPL) system which projects reticle patterns onto a wafer will be applied to sub 100 nm lithography. Requirements for line width accuracy are very strict as feature sizes are less than 100 nm. For electron beam lithography, proximity effect corrections have always been an important issue for accurate feature width control. In this paper characteristics of several correction methods are examined, and appropriate correction methods for 100 kV EPL are introduced. Employing the shape correction method burdens the reticle pattern preparation system much more than other methods. Therefore a calculation method suitable for 100 kV EPL where the backscatter radius is very wide ((beta) b approximately equals 30 micrometer) and the forward scatter radius is narrow ((beta) f approximately equals 7 nm) has been developed. The calculation of deposition energy by the backscattered electron beam is carried out with a coarse grid but wide range. The calculation of the combined effect of the electron scattering blurs from the features is carried out only within a narrow range. The correction calculation is carried out using both of these results. Using this method, accurate and fast calculations can be achieved. Employing the GHOST correction method increases total exposure cost. The practical GHOST correction methods may also be improved. An additional correction method named shape correction with GHOST is also shown.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Electron beam exposure method

Abstract: PURPOSE:To draw a pattern, which hardly displays a proximity effect and has high accuracy, in a short drawing time by drawing the pattern while varying acceleration voltage in response to the pattern. CONSTITUTION:A pattern is drawn while varying acceleration voltage in response to the size of the pattern. The pattern such as a pattern 1 (20mumX20mum) having size of not less than 1mum width is drawn is drawn by acceleration voltage of 10kv, and the pattern such as a pattern 2 (0.5mumX30mum) having size of less than 1mum width is drawn by using acceleration voltage of 80kv. Accordingly, exposure time may be reduced to one fourth times or less as long both the pattern 1 and the pattern 2 are exposed by 80kv, and the fine pattern in 0.5mum width can be formed by sufficient resolution because it is drawn by acceleration voltage of 80kv.

Electron beam exposure method and electron beam irradiation device

Abstract: PURPOSE:To reduce exposure time for forming a resist pattern and reduce proximity effect by enabling acceleration voltage of an electron beam of a process for irradiation on the entire surface to be set to optional value for the acceleration voltage of the electron beam CONSTITUTION:Exposure of a pattern part 12a is performed by using an electron beam 13 and then exposure is performed by an electron beam A for collective irradiation Then, an inversion pattern part 12b is exposed extremely weakly by irradiation on the entire surface The electron beam A for collective irradiation may be equal to, higher than, or lower than the same acceleration voltage as that of the electron beam 13 for drawing and the amount of exposure is 30 to 40% of the electron beam 13 for drawing Also, if acceleration voltage of the electron beam A for collective irradiation is too low, the part closer to a substrate 11 within a resist 12 may not be exposed Then, when the resist 12 is developed by a week development liquid, a pattern 15 is formed, thus reducing time required for exposure drastically and improving dimensional accuracy of a fine pattern, reducing approximately effect