Pattern fidelity improvement

Data preparation

Author of presentation

Ivanova Elvira

Data preparation

• Vistec EBPG5000 series systems allow a hierarchical organization of the pattern data. This reduces data preparation time and data volume significantly. With the layout postprocessor MGS which also covers a fracturing engine, the hierarchy of the pattern data can be created automatically.

Data preparation

• In such a hierarchy separately, what avoids the necessity for flattening of the whole layout.

In addition, special MGS options like restoring 45° edges, filling of non-boundary regions and special approximation of slanted edges allow the creation of optimized pattern data for the ZBA tools.

Data preparation

• And a RAID - System of at least 72 Gigabyte for data storage is available in the basis ZBA configuration. For layout data input, all relevant data formals as GDSII, DXF,CIF,MEBES, etc. can be used. For conversation of the input data into ZBA runtime format for exposure, pattern are pre-fractured to trapezium composition and further converted into exposure stripes, sub-fields and shots, which are finally stored in hierarchically organized runtime files with a significantly minimized data volume.

We can see an example of pre-fracturing result of a doughnut pattern. After pre-fracturing, the pattern in each stripe is converted to the elementary shapes for exposure. The conversion result format is shown in figure.

PATTERN FIDELITY IMPROVEMENT

• The pattern fidelity improvement on the EBDW technology becomes more and more important for defining patterns with small dimensions. Hereby edge roughness and CD accuracy influence the performance and functionality of a device significantly. Inaccurate definitions of patterns would lead to low yields and productivities in device manufacturing.

PATTERN FIDELITY IMPROVEMENT

• For improving pattern fidelity, advanced writing techniques and tool adjustment procedures, powerful simulation and correction software tools as well as improved tool to technology adaptation methods have been applied. For example, the edge roughness of a pattern is affected by the adjusted shot size, the stitching accuracies of neighboring shots,

PATTERN FIDELITY IMPROVEMENT

• sub fields and exposure stripes, and electron scattering effects - the proximity effect. In our tests, the induced CD variation can be minimized by using beam sizing and special pattern smoothing procedures. Moreover, efficient proximity effect correction and pattern bias compensation methods have been used to improve CD accuracy. CD uniformity and edge roughness significantly.