Ims Ionen Mikrofabrikations Systeme Gesellschaft M.b.h.

Oesterreichische Investitionskredit Aktiengesellschaft

Ims Ionen Mikrofabrikations Systeme Gesellschaft

Osterreichische Investitionskredit Aktiengesellschaft

Oesterreichische Investitionskredit Aktiengesellschaft and Ionen

Hilton F Glavish

Gerhard Stengl

Hans Loschner

Alfred Chalupka

Ernst Hammell

Gerhard Stengel

Apparatus and method for projection ion beam lithography are described which allow formation of low distortion, large field, reduced images of a mask pattern at a wafer plane using an optical column of practical size. The column shown is comprised of an accelerating Einzel lens followed by a gap lens, with numerous cooperating features. By coordinated selection of the parameters of the optical column, lens distortion and chromatic blurring are simultaneously minimized. Real time measurement of the position of the image field with respect to the existing pattern on the wafer is employed before and during the time of exposure of the new field and means are provided to match the new field to the existing pattern even when the latter has been distorted by processing. A metrology system enables convenient calibration and adjustment of the apparatus.

Ion beam lithography

In an ion projection lithography system, apparatus and methods for positioning on a substrate or wafer at a target station an image of structures provided on a mask, wherein the mask includes reference marks to provide ion reference beams about the image field, the target station includes marks and the beam of the system is controlled to establish a coincidence of the marks on the mask with the corresponding marks at the target station. The ion projection system shown includes in this optical path an electrostatic multipole, means for rotational adjustment of the image relative to the substrate, and means for correcting the scale of the image. Embodiments are shown in which the marks at the target station are carried on the wafer or on a reference block which is positionally related to the wafer, e.g., by an interferometer. In the case of the reference block, it has an aperture corresponding in size to the mask image to be formed on the substrate so that the marks are disposed outside the optical path used to generate the image on the substrate. Detectors provided for secondary radiation emitted by the marks at the target station as a result of the ion reference beams passing through the marks on the mask produce signals that control the multipole, the means for relative rotational adjustment of the image on the substrate and the means for scale correction. Special masks are provided that enable the reference beams to reach their respective marks at the target station during blanking and unblanking of the mask, permitting operation of the alignment system at both times. The reference beams are shielded from the image beam and are scanned repeatedly over their respective marks at the target station.

Method and apparatus for image alignment in ion lithography

A system for stabilizing an irradiated mask for use in lithographic set-ups, the mask including formations which are permeable to electromagnetic or corpuscular radiations, especially ion beams, the system having one or more cooling surfaces that surround the beam axis, are disposed in the field of view of the mask, and are located between the mask and the radiation source and/or behind the mask. The cooling surfaces preferably are in the form of surfaces of revolutions, are comprised of metal, have grooves that produce multiple reflections of the thermal radiation and are spaced equal distances apart from the axis of the optical path. The distances from the cooling surfaces to the axis of the optical path preferably exceed the distance from the edge of the mask sheet to the axis of the optical path. The mask is disposed in a chamber which is maintained by automatic control at a constant temperature, particularly at room temperature, e.g. by heating of the walls. The mask sheet is movable in the chamber to extend in front of an opening that is formed in a chamber wall and disposed in the optical path; the opening optionally being formed in a shutter which constitutes a part of the chamber wall, and the cooling surfaces are disposed in the field of view of the mask when the latter is disposed in front of the opening in the optical path, so that the heating action of the beam of radiation on the mask can be compensated by the cooling surfaces and the mask will be maintained approximately at the chamber temperature also during an irradiation.

Arrangement for stabilizing an irradiated mask

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Salem, MA, United States of America

Hilton F Glavish