Carl Zeiss Smt Gmbh

Carl Zeiss Ag

Carl Zeiss Sms Ltd.

Mario Laengle

Ulrich Matejka

Holger Seitz

Thomas Frank

Dirk Doering

Markus Koch

Norbert Rosenkranz

Klaus Gwosch

Daniel Pagel

Lukas Fischer

An optical measuring system is used to reproduce a target wavefront of an imaging optical production system when an object is illuminated with illumination light. The optical measuring system comprises an object holder displaceable by actuator means and at least one optical component displaceable by actuator means. Within the scope of the target wavefront reproduction, a starting actuator position set (X), in which each actuator is assigned a starting actuator position, is initially specified. An expected design wavefront (W) which approximates the target wavefront and which the optical measuring system produces as a set wavefront is determined. A coarse measurement of a starting wavefront (W) which the optical measuring system produces as actual wavefront after actually setting the starting actuator position set (X) is carried out. Then, the object holder is adjusted by actuator means until a coarse target wavefront (W) is obtained for a coarse actuator position set (X) in the case of a minimum wavefront deviation between the actual wavefront and the design wavefront (W). Said coarse target wavefront is then subjected to a fine measurement and the at least one optical component is displaced until a fine target wavefront (W) is obtained for a fine actuator position set (X) in the case of a minimum deviation between the actual wavefront setting-in in that case and the design wavefront (W). This reproduction method allows wavefront deviations of the optical measuring system generated by way of targeted misalignment to provide a good approximation of corresponding deviations of the optical production system.

Method for reproducing a target wavefront of an imaging optical production system, and metrology system for carrying out the method

The invention relates to a device for measuring a mask for microlithography, the device including an imaging device and an autofocusing device. The imaging device comprises an imaging optical unit with a focal plane for imaging the mask, an object stage for mounting the mask, and a movement module for producing a relative movement between object stage and imaging optical unit. The autofocusing device is configured to generate a focusing image by way of the imaging of a focusing structure in a focusing image plane intersecting the focal plane, in which the focusing structure is embodied as a gap. Furthermore, the invention relates to an autofocusing method for a device for measuring a mask for microlithography.

Device for measuring masks for microlithography and autofocusing method

An illumination optical unit serves for illuminating objects to be examined by a metrology system. The illumination optical unit has an optical pupil shaping assembly for generating a defined distribution of illumination angles of illumination light over an object field in which an object to be examined can be arranged. An optical field shaping assembly for generating a defined intensity distribution of the illumination light over the object field is disposed downstream of the pupil shaping assembly in the beam path of the illumination light. The field shaping assembly has at least one optical field shaping element arranged in the region of a pupil plane of the illumination optical unit. This results in an illumination optical unit which ensures an illumination which can be set in a defined manner with regard to an intensity distribution and an illumination angle distribution over the entire object field.

Illumination optical unit for a metrology system and metrology system comprising such an illumination optical unit

A method for establishing distortion properties of an optical system in a microlithographic measurement system is provided. The optical system has at least one pupil plane, in which the distortion properties of the optical system are established on the basis of measuring at least one distortion pattern, which the optical system generates when imaging a predetermined structure in an image field. The distortion properties of the optical system are established on the basis of a plurality of measurements of distortion patterns, in which these measurements differ from one another in respect of the intensity distribution present in each case in the pupil plane.

Method for establishing distortion properties of an optical system in a microlithographic measurement system

During mask inspection it is necessary to identify defects which also occur during wafer exposure. Therefore, the aerial images generated in the resist and on the detector have to be as far as possible identical. In order to achieve an equivalent image generation, during mask inspection the illumination and, on the object side, the numerical aperture are adapted to the scanner used. The invention relates to a mask inspection microscope for variably setting the illumination. It serves for generating an image of the structure () of a reticle () arranged in an object plane in a field plane of the mask inspection microscope. It comprises a light source () that emits projection light, at least one illumination beam path (), and a diaphragm for generating a resultant intensity distribution of the projection light in a pupil plane () of the illumination beam path () that is optically conjugate with respect to the object plane. According to the invention, the diaphragm is embodied in such a way that the resultant intensity distribution of the projection light has at least one further intensity value between a minimum and a maximum intensity value.

Mask inspection microscope with variable illumination setting

A method is provided for determining the position of a structure within an image relative to a reference point, in which the structure has a center of symmetry, the method comprising: providing an image which comprises the structure and which has a reference point, carrying out at least one symmetry operation of the image with respect to the reference point, by means of which at least one mirror image is obtained which has a mirrored structure congruent relative to the structure, determining at least one displacement vector between a structure and a mirrored structure or two mirrored structures, and calculating the position of the structure as a position of the center of symmetry of the structure relative to the reference point from the at least one displacement vector. Furthermore, a position measuring device is provided for determining the position of a structure within an image relative to a reference point.

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Jena, Germany

Mario Laengle