International Business Machines Corporation

Gernot Brasen

Christian Laue

Matthias Loeffler

Heiko Theuer

Frank Lautenbach

Matthais Loeffler

The present invention provides a method, an optical inspection apparatus as well as a computer program product for optical inspection of a surface. The optical inspection apparatus can be effectively applied for optical inspection of periodic structures on e.g. a semi-conductor wafer for the purpose of quality control. By effectively splitting a light beam into a plurality of spatially separated light beams and by selective usage of these light beams, various surface segments of the surface can be inspected simultaneously by superposition of respective images. A resulting superposition image can then be compared with a reference image for detection of defects of the surface.

Optical surface inspection

The invention relates to an interferometric method for measuring a height of a first region on a first surface, the first surface having first areas having first optical properties and second areas having second optical properties, the method comprising the steps of generating of first and second coherent light beams, reflecting at least the first coherent light beam from the first region into a first return beam and reflecting the second coherent light beam from a second region into a second return beam, measuring at least a first reflectivity of the first region, determining a topography-dependent phase shift of the first and second return beams for the height measurement based on the first reflectivity.

Interferometric Height Measurement

Interferometric height measurement

A system and method for interferometric height measurement. A first coherent light beam and a second coherent light beam is generated. At least the first coherent light beam is reflected from a first region into a first return beam and the second coherent light beam is reflected from a second region into a second return beam. At least a first reflectivity of the first region is measured. A topography-dependent phase shift of the first return beam and the second return beam is determined with reference to a curve relating the first reflectivity to a material-dependent phase shift. A height based on the topography-dependent phase shift is measured.

Method and system for interferometric height measurement

The invention relates to a system and method of detecting impurities in a cylindrically shaped transparent medium, wherein the cylindrically shaped transparent medium is illuminated with electromagnetic radiation, and the radiation having components emerging radially from the medium, and at least some of the components are received by a detector for detecting impurities of the medium. The components are detected at a multiplicity of relative angular positions around the symmetry axis of the cylinder, so as to form an impurity diagram that may be analyzed to detect and measure impurities in the medium.

Detection of impurities in cylindrically shaped transparent media

A polarizing beamsplitter is provided, comprising two wedge-shaped prisms of a birefringent material, the prisms forming a plan-parallel plate, wherein an incident light beam is separated into two partial beams being arranged parallel to the incident beam when emerging from the beamsplitter, the partial beams having a lateral distance with respect to each other, which is continuously changeable.

Polarizing beamsplitter

A method for controlling the position of a probe location relative to a fixed reference point of a probe processing apparatus is described. Initially, an optical laser apparatus is coupled to the probe processing apparatus. The position of the probe location is set to fall within a predetermined converging range of a positioning laser beam coming from the optical laser apparatus. The positioning laser beam is then split into a probe beam and a reference beam. The probe beam and the reference beam are polarized in different directions with respect to each other. The reference beam is subsequently combined with a reflected beam formed by the probe beam reflected from the probe location. The phase difference between the reference beam and the reflected beam is detected, and a table on the probe processing apparatus for supporting the probe is adjusted to minimize the detected phase difference.

Method and apparatus for controlling the position of a probe location relative to a fixed reference point of a probe processing equipment

An optical device has a rotatable birefringent crystal. The crystal is rotatable around a first axis () and has a crystallographic-optical axis () in a plane that is perpendicular to the first axis. In addition, the crystal is rotated around the first axis in order to control a displacement (&#x394;x) of a light beam in the plane when the light beam is polarized within the plane and directed onto the crystal.

Growing community of inventors

Mainz, Germany

Gernot Brasen