Abstract: A metrological apparatus includes an optical measurement system (1) such as a coherence scanning interferometer operable to obtain measurement data representative of a surface of a workpiece and a rotation device (15) to effect relative rotation between the optical measurement system and the workpiece about a measurement axis to enable a plurality of measurement data sets to be obtained with each measurement data set being obtained by the optical measurement system at a respective one of a number of different relative rotational orientation s of the optical measurement system and the workpiece. A data corrector (323) is provided to obtain correction data to enable correction of a measurement data set. The correction data may be an average of the plurality of measurement data sets.

Abstract: A surface measurement instrument for obtaining surface characteristic data of a sample surface is described. Relative movement between a reference surface and a sample support is caused to occur while a sensor senses light intensity at intervals along a scan path to provide a series of intensity values representing interference fringes produced by a region of a sample surface during said relative movement and from which series of intensity values surface characteristic data can be derived. The sample support is both translatable and tiltable in at least one direction perpendicular to a scan direction so that the sample support can be both tilted to cause the scan path to be normal to the sample surface region and translated to compensate for translation movement due to the tilting.

Abstract: A surface measurement instrument for obtaining surface characteristic data of a sample surface is described. Relative movement between a reference surface and a sample support is caused to occur while a sensor senses light intensity at intervals along a scan path to provide a series of intensity values representing interference fringes produced by a region of a sample surface during said relative movement and from which series of intensity values surface characteristic data can be derived. The sample support is both translatable and tiltable in at least one direction perpendicular to a scan direction so that the sample support can be both tilted to cause the scan path to be normal to the sample surface region and translated to compensate for translation movement due to the tilting.

Abstract: Broadband light is directed along sample and reference paths such that light reflected by a sample surface and light reflected by a reference surface interfere. A mover effects relative movement between the sample and reference surfaces along a scan path. A detector senses a series of light intensity values representing interference fringes produced by a sample surface region during the movement. A data processor processes the intensity values as they are received to produce coherence peak position data and, after completion of a measurement operation, uses this coherence peak position data to obtain data indicative of the height of the surface region. The data processor includes a correlator for correlating intensity values with correlation function data to provide correlation data to enable identification of a position of a coherence peak. A surface topography determiner determines a height of a sample surface region from coherence peak position data.

Abstract: A surface measurement instrument (1) for obtaining surface characteristic data of a sample surface (13) is described. Relative movement between a reference surface (11) and a sample support (15) is caused to occur while a sensor (16) senses light intensity at intervals along a scan path (SP) to provide a series of intensity values representing interference fringes produced by a region of a sample surface (13) during said relative movement and from which series of intensity values surface characteristic data can be derived. The sample support (15) is both translatable and tiltable in at least one direction perpendicular to a scan direction so that the sample support (15) can be both tilted to cause the scan path (SP) to be normal to the sample surface region and translated to compensate for translation movement due to the tilting.

Abstract: An interferometer system (2) directs light along a sample path (SP) towards a sample surface (7) and along a reference path (RP) towards a reference surface (6). Light reflected by a sample surface region and by the reference surface interfere. Sensing elements (SE) sense interference fringes at intervals along a scan path to provide a set of intensity data. A coherence peak position determiner (201) determines from the intensity data set a position on the scan path that corresponds to the height of the surface region. An amplitude determiner (202) determines amplitude data representing the amplitude of the intensity data at the determined height position. A modified surface height calculator (207) calculates modified height data by modifying the height data by a correction factor determined using the corresponding amplitude data and a correction parameter provided by a correction parameter provider (260).

Abstract: Light is directed along a sample path towards the sample surface and along a reference path towards a reference surface such that light reflected by the sample surface and light reflected by the reference surface interfere. Relative movement is effected between the sample surface and the reference surface along a measurement path and the light intensity resulting from interference between light reflected from the reference surface and regions of the sample surface is sensed at intervals along the measurement path to provide a number of sets of light intensity data values with each light intensity data value representing the sensed light intensity associated with a corresponding one of said regions. The sets of light intensity data are processed to determine a position along the measurement path at which a predetermined feature occurs in the light intensity data for each sensed region and to enhance image data representing the intensity data to facilitate the detection by a user of the interference fringes.

Abstract: A surface measurement instrument (1) for obtaining surface characteristic data of a sample surface (13) is described. Relative movement between a reference surface (11) and a sample support (15) is caused to occur while a sensor (16) senses light intensity at intervals along a scan path (SP) to provide a series of intensity values representing interference fringes produced by a region of a sample surface (13) during said relative movement and from which series of intensity values surface characteristic data can be derived. The sample support (15) is both translatable and tiltable in at least one direction perpendicular to a scan direction so that the sample support (15) can be both tilted to cause the scan path (SP) to be normal to the sample surface region and translated to compensate for translation movement due to the tilting.

Abstract: A broad band surface profiling apparatus including a reference calibrator for calibrating the apparatus to compensate for surface features of the reference surface. A user is instructed to conduct calibration measurement operations using a calibration sample having a calibration surface to obtain calibration surface topography data for the calibration sample. At each calibration measurement operation, an image representing the calibration surface topography data is displayed to the user and the user has the option to accept or reject the calibration surface topography data represented by the displayed image. The reference calibrator has a surface topography data processor and a mean surface calculator for calculating mean surface topography data using the processed calibration surface topography data accepted by the user to provide reference surface features data.

Abstract: Light from a broadband source (4) is directed along a sample path (SP) towards a region of a sample surface (7) and along a reference path (RP) towards a reference surface (6) such that light reflected by the region of the sample surface and light reflected by the reference surface interfere. A mover (11) effects relative movement along a scan path between the sample surface (7) and the reference surface (6). A detector (10) senses light intensity at intervals to provide a series of intensity values representing interference fringes produced by a region of a sample surface.

Abstract: A surface profiling apparatus and method. Broadband light is directed along sample and reference paths such that light reflected by a region of a sample surface and light reflected by a reference surface interfere. A mover effects relative movement between the sample and reference surfaces along a scan path. A detector senses a series of light intensity values representing interference fringes produced by the region of the sample surface during the movement. A data processor processes the intensity values as they are received during a measurement operation to produce data indicating the position of a coherence peak, and, after completion of a measurement operation, uses this coherence peak position data to obtain data indicative of the height of the surface region. The data processor includes a correlator for correlating intensity values with a correlation function to provide correlation data to enable the position of a coherence peak to be identified.