New Electron Beam Proximity Effects Correction Approach for 45 and 32 nm Nodes

Abstract

After the successful results obtained these last years, electron beam direct write (EBDW) lithography use for integrated circuit manufacturing has now been demonstrated. However, throughput and resolution capabilities need to be improved to push its interest for fast cycle production and advanced research and development applications. In this way, the process development needs good patterns dimensional accuracy, i.e., a better control of the proximity effects caused by back scattering electrons and others phenomenon. It exists several methods to provide a correction for these effects and the most commonly used is based on dose modulation. However it has been observed that this correction is not perfect and can significantly fail to accurately correct the smallest and most dense structures encountered in sub 65 nm design features. To continue reducing feature sizes a method to provide a complementary correction to the dose modulation solution is proposed. Based upon detailed characterization of the observed effects a rules correction scheme has been developed not dissimilar to the rule based corrections used in optical proximity correction (OPC). This rule based electron beam proximity correction, or R-EBPC, provides good results down to 40 nm, with improvements in critical dimension (CD) linearity, the isolated dense bias, line end shortening and the energy latitude. All of which leads to an improvement in the overall accuracy of the design, and furthermore an improvement in the process window.

Reliable fabrication of 3 nm gaps between nanoelectrodes by electron-beam lithography

“…The stability of the mask-bridge can be rated by the estimation of the remaining thickness after development. As described in [14] a relative dose of 0.35 of the necessary exposure dose corresponds to a remaining relative thickness of approximately 22 nm in the central part of the mask-bridge in the second nanoelectrode design. On the other hand, a relative dose of 0.80 of the necessary exposure dose corresponds to a remaining relative thickness of the resist layer of approximately 15 nm, which seems to be a stable thickness for the mask layer resist in boundary structures.…”

“…A correction of this proximity effect related exposure can be performed with the commercially available program PROXECCO. However, this method significantly fails to correct features below 65 nm accurately [14]. Here we will show the fabrication of sub-5 nm structures by EBL using as well an optimized lift-off process based on a double layer resist stack as an improved strategy for a proximity effect correction at short range.…”

Analysis of irradiance distribution in optical proximity printing of micro annulus apertures

“…Optical proximity printing is a cost-effective process for fabricating micro components among many others. [1][2][3][4][5][6][7][8][9][10][11] However, the pattern transferred from mask is distorted when the size of aperture reduced. As an example, Fig.…”