Mask membrane distortions due to pattern transfer for electron-beam lithography (SCALPEL) masks

摘要

In order to successfully employ Scattering with Angular Limitation Projection Electron-Beam Lithography (SCALPEL) to produce integrated circuits with features below 0.13 μm, mask membrane distortions (which lead to pattern placement errors) must not exceed the error budget. When designing a mask, finite element (FE) models are created to identify sources of distortion and quantify the resulting errors. Distortions arise during fabrication, mounting, and in situ exposure of the mask. The focus of this study was to determine the mask membrane distortions induced during the pattern transfer process for a large format SCALPEL mask. Three cases were investigated; the IBM Talon pattern, l00 removal of the scatterer layer, and 50 removal of the scatterer layer. The IBM Talon pattern was chosen to quantify typical pattern specific-distortions while the other two cases, 100 and 50 removal of the scatterer layer, were investigated to determine distortions corresponding to worst case situations.