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.

Electron beam lithography method and mask for electron beam lithography

Abstract: PROBLEM TO BE SOLVED: To provide an electron beam lithography method and a mask for electron beam lithography, with which a fine pattern can be written precisely by proximity effect correction and productivity can be improved. SOLUTION: A design pattern to be written is divided, depending on the area density distribution of a design pattern. By using a mask for electron beam lithography patterned for each divided region, each divided region is irradiated with a different irradiation dose of electron beam for correcting proximity effect. The design pattern to be written is divided, depending on the area density distribution of the design pattern, and the mask is patterned for each divided region.

Geometrical correction of the e-beam proximity effect for raster scan systems

Abstract: Increasing demands on pattern fidelity and CD accuracy in e- beam lithography require a correction of the e-beam proximity effect. The new needs are mainly coming from OPC at mask level and x-ray lithography. The e-beam proximity limits the achievable resolution and affects neighboring structures causing under- or over-exposion depending on the local pattern densities and process settings. Methods to compensate for this unequilibrated does distribution usually use a dose modulation or multiple passes. In general raster scan systems are not able to apply variable doses in order to compensate for the proximity effect. For system of this kind a geometrical modulation of the original pattern offers a solution for compensation of line edge deviations due to the proximity effect. In this paper a new method for the fast correction of the e-beam proximity effect via geometrical pattern optimization is described. The method consists of two steps. In a first step the pattern dependent dose distribution caused by back scattering is calculated by convolution of the pattern with the long range part of the proximity function. The restriction to the long range part result in a quadratic sped gain in computing time for the transformation. The influence of the short range part coming from forward scattering is not pattern dependent and can therefore be determined separately in a second step. The second calculation yields the dose curve at the border of a written structure. The finite gradient of this curve leads to an edge displacement depending on the amount of underground dosage at the observed position which was previously determined in the pattern dependent step. This unintended edge displacement is corrected by splitting the line into segments and shifting them by multiples of the writers address grid to the opposite direction.

Optimization of distributed implementation of grayscale electron-beam proximity effect correction on a temporally heterogeneous cluster

Abstract: Grayscale electron-beam lithography is one of the techniques used in transferring circuit patterns with multi-level structures onto substrates. The proximity effect caused by electron scattering imposes a severe limitation on the ultimate spatial resolution attainable by e-beam lithography. Therefore, proximity effect correction is essential particularly for fine-feature, high-density circuit patterns. One difficulty is that it is extremely time-consuming due to the intensive computation required in the correction procedure and a large size of circuit data to be processed. Hence, it is an ideal candidate for distributed computing where the otherwise-unused CPU cycles of a number of computers on a network (cluster) can be efficiently utilized. In this paper, optimization of the distributed grayscale proximity effect correction procedure previously developed is addressed for minimizing the correction time. Also, a different circuit partitioning approach (localized partitioning) is considered.