Embodiments of systems and methods for measuring a surface topography of a semiconductor chip are disclosed. In an example, a method for measuring a surface topography of a semiconductor chip is disclosed. A plurality of interference signals and a plurality of spectrum signals are received by at least one processor. Each of the interference signals and spectrum signals corresponds to a respective one of a plurality of positions on a surface of the semiconductor chip. The spectrum signals are classified by the at least one processor into a plurality of categories using a model. Each of the categories corresponds to a region having a same material on the surface of the semiconductor chip. A surface height offset between a surface baseline and at least one of the categories is determined by the at least one processor based, at least in part, on a calibration signal associated with the region corresponding to the at least one of the categories. The surface topography of the semiconductor chip is characterized by the at least one processor based, at least in part, on the surface height offset and the interference signals.

A method for determining a separation distance between a working head in a machine for laser processing a material and a surface of the material includes generating a measurement beam of low coherence optical radiation, leading the measurement beam towards the material and a reflected or diffused measurement beam towards an optical interferometric sensor arrangement in a first direction of incidence, generating a reference beam of low coherence optical radiation, leading the reference beam towards the optical interferometric sensor arrangement in a second direction of incidence superimposing the measurement and reference beams on a common region of incidence, detecting a position of a pattern of interference fringes between the measurement and reference beams on the common region of incidence, and determining a difference in optical length between the measurement and reference optical paths based on the position of the pattern of interference fringes along an illumination axis.

An interferometry apparatus comprising: a laser source operable to emit a first light beam; a beam splitter arranged to split the first light beam into an object beam and a reference beam, the object beam passing along an object beam arm and the reference beam passing along a reference beam arm; an adaptive delay line located a distance along the reference beam arm, the adaptive delay line being configured to provide, in use, one or more length-adjusted reference beams; a beam splitter arranged to recombine the object beam from the object beam arm and the length-adjusted reference beam(s) from the reference beam arm; and a photodetector operable to detect interference between the object beam and the length-adjusted reference beam(s).

A background subtraction method and tilt stage device for eliminating contaminated or spurious interference patterns by reducing retrace errors. An optical reference surface secured in a pivoting mount coupled to a tilt actuator is configured to angularly displace the pivoting mount and optical reference surface. A microcontroller coupled to the tilt actuator controls the tilt displacement of the tilt actuator providing a plurality of wavefront measurements of the reference surface at a plurality of angles to provide a system and method for background measurement.

A device includes a first component, a second component having a reconfigurable distance from the first component, an optical element, an SMI sensor, and a processor. The optical element has a fixed relationship with respect to the first component, and has a known optical thickness between a first surface and a second surface of the optical element. The SMI sensor has a fixed relationship with respect to the second component, and has an electromagnetic radiation emission axis that intersects the first and second surfaces of the optical element. The processor is configured to identify disturbances in an SMI signal generated by the SMI sensor, relate the disturbances to the known optical thickness of the optical element, and to determine a distance between the first and second components using the SMI signal and the relationship of the disturbances to the known optical thickness of the optical element.

A method for determining local position of an optical element associated with an optical path for transporting a laser beam in a working head of a machine for laser processing a material, includes generating a measurement beam of low coherence optical radiation traveling a measurement optical path, leading the measurement beam towards the optical element and the reflected or diffused measurement beam towards an optical interferometric sensor arrangement, generating a reference beam of low coherence optical radiation traveling a reference optical path and leading the reference beam towards the interferometric optical sensor arrangement, superimposing the measurement and reference beams on a common region of incidence, detecting a position of a pattern of interference fringes between the measurement and reference beams, and determining a difference in optical length between the measurement and reference optical paths as a function of the position of the interference pattern along an illumination axis, or of the frequency of the interference pattern in the frequency domain.

A measuring device (10) for the interferometric shape measurement of a surface (12) of a test object (14-1; 14-2)includes (i) a diffractive optical element (26-1; 26-2) that generates a test wave (28) from incoming measurement radiation (18), wherein the diffractive optical element radiates the test wave onto the surface of the test object, (ii) a deflection element (22) that is disposed upstream of the diffractive optical element in the beam path of the measurement radiation, and (iii) a holding device (24, 124) that holds the deflection element and that changes a position of the deflection element (22) through a combination of a tilting movement and a translation movement.

An analysis apparatus includes an acquisition part that acquires a plurality of interference images based on lights having a plurality of different wavelengths from an interference measurement apparatus, a removing part that outputs an interference component by removing a non-interference component included in an interference signal for each pixel in the plurality of the interference images, a conversion part that generates an analysis signal by performing a Hilbert transformation on the interference component, and a calculation part that calculates a distance between a reference surface and a surface of an object to be measured by specifying a phase gradient of a wavelength of light radiated onto the reference surface and the surface of the object to be measured on the basis of the interference component and the analysis signal.

A computer program product for numerically correcting an endpoint position of a Coordinate Measuring Machine (CMM) implemented on a computing unit, receiving as input temporally resolved information from a set of sensors attached to or integrated into the CMM, and to a method for numerically correcting an endpoint position of a CMM, wherein errors between a targeted endpoint position and an actual endpoint position reached during a measurement process are numerically compensated through the use of the computer program product.

A measurement apparatus for interferometric shape measurement of a test object surface. A test optical unit produces from measurement radiation a test wave for irradiating the surface. A reference element with an optically effective surface interacts with a reference wave also produced from the measurement radiation. An interferogram is produced by superimposing the test wave after interaction with the test object's surface. A holding device holds the reference element and moves the reference element relative to the reference wave in at least two rigid body degrees of freedom so that a peripheral point of the reference element's optically effective surface shifts by at least 0.1% of a diameter of the optically effective surface. The at least two degrees of freedom include a translational degree, directed transversely to a propagation direction of the reference wave and a rotational degree, whose rotational axis aligns substantially parallel to the reference wave's propagation direction.