Lecture9 E-BEAM Direct WRITE SERIES

E-BEAM Direct WRITE SERIES

Author of presentation

Ivanova Elvira

The high solutions of a difficulty

• Methods such as beam sizing, double-pass expose, pattern-bias compensation as well as proximity effect correction are introduced to alleviate infinite stripe stitching inaccuracies, influence of proximity effects and other influences caused by the impinging electrons. In result, the edge roughness can be improved and the pattern dimension can be consequently controlled.

The high solutions of a difficulty

To resolve the low throughput issue which is typical for the serially working architecture of E-Beam lithography, several appropriate, and in partition unique principles have been taken into account for the development of the Vistec EBPG5000 Series.

The high solutions of a difficulty

The vector - scan shaped-beam architecture is of course the basic principle for increasing the throughput initially during the pattern generation and beam positioning in the column during the exposure which runs shot after shot. Furthermore, the write on the fly principle is applied for accurate and efficient stage moving time during the exposure run. To achieve a high accuracy stage to beam synchronization, a beam tracking deflector is located in the final lens for high precise fine correction.

The high solutions of a difficulty

• The operation of substrate loading and the stabilizing of the substrate parallel to a running exposure are applied to avoid any loss in time for these procedures. Finally, for further increasing the throughput for manufacturing of IC-typical repetitive patterns,

The high solutions of a difficulty

• Vistec EBPG5000 Series Direct Write systems can be optionally supplied with implementation of the Mini-reticle Projection Technology. This enables the system to expose a composite pattern with one shot and leads to writing times of about one third of the results achieved with the conventional shaped beam method.

The high solutions of a difficulty

• In a shaped beam system the election beam is imaged through two or more successive square apertures to form a rectangular cross-section, sometimes also triangular cross-sections can be generated. With the help of very high speed electrostatic shape deflectors the final cross-section of the beam can be varied in both axes.

The high solutions of a difficulty

• This beam shape is then demagnified and focused onto the substrate. With this type of exposure system the equivalent of hundreds of spot beams can be exposed in one single step. Variable shaped beam systems have significantly improved the throughput over Gaussian beam systems.

The high solutions of a difficulty

• The Vistec EBPG5000 Series tools are based on the variable-shaped beam principle. We show obviously that two diaphragms which are limiting the electron beam, are arranged at different levels. Each of these two diaphragms has four quadratic apertures. It is possible to generate several shot shapes by partial or total imaging an aperture of the first diaphragm at an aperture of the second diaphragm.

The high solutions of a difficulty

• In the standard case these shapes are: rectangles with parallel edges, in X and Y , rectangles rotated by 45° as well as 4 types of right-angled triangles. In case the mini-reticle projection technology is implemented, composite mini-reticles can be generated with one shot.

The high solutions of a difficulty

• Utilising these 6 different shape types, it became possible to expose with high productivity even patterns with slopped edges.