Infineon Technologies Ag

Siemens Aktiengesellschaft

Fritz Gans

Rainer Pforr

Torsten Franke

Uwe Griesinger

Christoph Friedrich

Günther Ruhl

Tarek Lutz

J&ouml;rg Thiele

Werner Fischer

J&uuml;rgen Knobloch

Wilhelm Maurer

Bernd Schönherr

Christian Ebi

Frank Erber

Klaus Ergenzinger

A method for compensating for scatter/reflection effects in particle beam lithography includes the following steps: providing at least one layer of a material that is sensitive to particle beams, using at least one particle beam to write predetermined patterns in a limited area of the material that is sensitive to particle beams, and using at least one particle beam to write at least one frame, which surrounds the limited area, into the material that is sensitive to particle beams so that variations in the background dose within the limited area are less than 30% of the maximum background dose within the limited area. This provides the advantage that a considerably more homogeneous background dose and hence considerably less variation in the CD measure, can be produced within the area that is written to by the particle beam, in a simple and cost-effective manner.

Method for compensating for scatter/reflection effects in particle beam lithography

A mask contains a transparent carrier material on which an opaque region is disposed as an image structure. Also disposed on the carrier material is a semitransparent dummy structure, which is spaced apart from all the image structures and differs from the image structure in terms of transparency and phase rotation. The smallest lateral extent of the dummy structure is then selected to be at least half as large as the smallest lateral extent of the image structure. The semitransparent dummy structure is formed in such a way that it is suitable for increasing the depth of focus of structures that stand individually or at least partially individually, in order thereby to improve the process window of the optical projection.

Mask for optical projection systems, and a process for its production

A pattern with small, densely packed structures is transferred from a structure carrier to an object. At least two partial patterns of less densely packed structure contents are produced from the densely packed structures in that those structures which are arranged close beside one another in the pattern on the structure carrier are assigned to various partial patterns if possible and separated from one another as a result. The partial patterns are then transferred to the object with a time offset and the structures are combined again as a result. This achieves a reduction in the structure density during the optical imaging process, so that the influence of disruptive structure interference on the imaging is reduced and thus denser structures can be imaged at the same wavelength.

Method of transferring a pattern of high structure density by multiple exposure of less dense partial patterns

For lithographically producing the smallest structures at less than the exposure wavelengths in semiconductor fabrication, a double exposure is carried out using a thick phase mask and a trimming mask, the trimming mask further structures the phase-contrast lines produced by the phase mask. Besides transparent or opaque regions, the trimming mask also has phase-shifting regions. These surround transparent regions of the trimming mask through which the phase-contrast lines produced by the first mask are locally re-exposed, that is to say interrupted. The intensity profile of successive line sections is especially rich in contrast through the addition of the phase-shifting partially transparent regions on the second mask; the distances between the line sections can be reduced. The trimming mask, otherwise used only for larger structures, is therefore suitable for the configuration of the finest dimensionally critical structures.

Trimming mask with semitransparent phase-shifting regions

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München, Germany

Fritz Gans