Methods for proximity effect correction in electron lithography

Abstract

A convenient and unambiguous way of characterizing the proximity effect is by use of the modulation transfer function. Six types of correction scheme are compared in this way, these being the use of high beam energies (>20 keV), of low beam energies (<20 keV), the use of multilayer resists, exact dose correction, ‘‘self-consistent’’ dose correction, and the application of correction exposures. The main conclusions drawn are that the use of high beam energies reduces the proximity effect significantly; that exact dose correction, in addition to performing better than the ‘‘self-consistent’’ technique, is computationally superior; and that correction exposures are effective, particularly in combination with other correction techniques.

Independent-Exposure Method in Electron-Beam Lithography

“…This proximity effect has been considered as negative effect for the others process as well as independent-exposure method in the electron beam lithography. Owen introduced some interesting methods to reduce the proximity effect: (1) the precise control of the electron beam energy, (2) the calculation and pre-compensation of the energy deposition and (3) the use of multilayer resist coatings (Owen, 1990). In addition, if the resist with low sensitivity to electron beam is used, it will be also good solutions.…”

Implementation of e-beam proximity effect correction using linear programming techniques for the fabrication of asymmetric bow-tie antennas

“…Physical approaches such as using high beam energies, low beam energies, and multilayer resists all intend to modify the point spread function in various ways. Although physical modification techniques seem very simple and practical, they are usually very application specific and do not offer a generic solution to the proximity effect problem [22,23,26,33,35].…”

“…In summary, short range proximity effects can be lessened using high energy beams. In turn, this causes worsening in the long range proximity effects, damage in the substrate and low throughput [23,26,35].…”

“…On the other hand, penetration depth is much shorter, and this inhibits the thick resist applications using this method [23,26,33] .…”

“…Although this polymer layer is not sensitive to electrons and it does not play an active role in real image forming, it cushions the high velocity electrons before they reach the substrate and lessens backscattering. However, this method is not very practical due to its high complexity in the fabrication process [22,26].…”