Infineon Technologies Ag

Siemens Aktiengesellschaft

Uwe Griesinger

Rainer Pforr

Christoph Friedrich

Andreas Grassmann

Dietrich Widmann

Molela Moukara

Burkhard Ludwig

Mario Hennig

Fritz Gans

J&uuml;rgen Knobloch

Michael Heissmeier

Manuel Vorwerk

Wilhelm Maurer

Jürgen Knobloch

Klaus Ergenzinger

Auxiliary openings are assigned to openings on a mask to be transferred to a wafer. These auxiliary openings have a phase-shifting property, preferably between 160&#xb0; and 200&#xb0; with respect to the openings, and a cross section lying below the limiting dimension for the printing of the projection apparatus, so that the auxiliary openings themselves are not printed onto the wafer. However, the auxiliary openings do enhance the contrast of the aerial image, in particular of an associated, isolated or semi-isolated opening on the wafer. The auxiliary openings may have a distance from the opening that lies above the resolution limit of the projection apparatus but that is less than the coherence length of the light used for the projection. A phase-related utilization of the optical proximity effect results, which can produce elliptical structures from square openings on the mask when the auxiliary openings are disposed in the preferential direction.

Photolithographic mask and methods for producing a structure and of exposing a wafer in a projection apparatus

The present invention provides a method for producing a photomask ( ), which has the following steps: provision of a mask blank with a substrate ( ) and a masking layer ( ) applied thereto; whole-area resist-coating of the mask blank with a photoresist; performance of a raster scan exposure of the photoresist in accordance with a predetermined photomask pattern in a pattern region (MB), which is separated from an edge ( ) of the mask blank by a peripheral edge region (RB); performance of the raster scan exposure in at least one peripheral partial region of the edge region (RB), which adjoins the edge ( ) on one side; development of the exposed photoresist; etching of the masking layer ( ); and removal of the photoresist. The present invention also provides a corresponding photomask.

Method for producing a photomask and corresponding photomask

An alternating phase mask having a branched structure containing two opaque segments is described. Two transparent surface segments are disposed on both sides of the segments or the components thereof, respectively. The surface segments are provided with phases that are displaced by 180&deg;&plusmn;&Dgr; &agr;, whereby &Dgr; &agr; a is not more than 25&deg;. The surface segments are separated by at least one transparent surface boundary segment whose phase is situated between the phases of the adjacent surface segments.

Alternating phase mask

The invention relates to a phase shift mask for lithographically producing small structures at the limit of a resolution that is predetermined by the wavelength of the exposure radiation. The phase shift mask has first regions A and second regions B that effect a phase-shift relative to the first regions. The second regions are arranged beside the first regions for producing a sudden phase shift along the boundaries between the first and the second regions. Individual first regions touch one another via corners at points, at which the second regions also touch one another via corners. The result is that the boundaries between first and second regions merge at these points and these points are opaque to the radiation. The invention makes it possible to expose extremely small contact holes with just a single exposure and thus leads to a reduction of costs in the fabrication of integrated semiconductor circuits.

Contact hole fabrication with the aid of mutually crossing sudden phase shift edges of a single phase shift mask

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

Growing community of inventors

Anzing, Germany

Uwe Griesinger