Abstract: An apparatus and method for determining a depth of a region having a high aspect ratio that protrudes into a surface of a semiconductor wafer are provided. The apparatus comprises a multi-wavelength light source, a semiconductor wafer holder for holding a semiconductor wafer, a head for directing the light source onto the semiconductor wafer, a spectrometer for collecting light comprising multiple wavelengths reflected from the semiconductor wafer and analysis means for determining a depth of the region from an interference pattern of light reflected from the semiconductor wafer by performing Fourier domain optical coherence tomography.

Abstract: According to a method for measuring the distance between a workpiece and a machining head of a laser machining apparatus, a machining head is provided, which has a housing that has an interior and an opening for emergence of the laser radiation from the machining head. The laser radiation is directed on to the workpiece, after it has passed through the interior and the opening. An object beam is directed on to the workpiece by a light source of an optical coherence tomograph in such a manner that the object beam passes through the interior and the opening before being incident upon the workpiece. In addition to the object beam, a measuring beam passes through the interior. The measuring beam is used to compensate falsifications of the measured distance that have been caused by pressure fluctuations in the interior. The measuring beam in this case may be reflected at a reflective face that is formed on an inner face of an outlet nozzle that comprises the opening, which inner face delimits the interior.

Abstract: Apparatus for monitoring a thickness of a silicon wafer with a highly-doped layer at least at a backside of the silicon wafer is provided. The apparatus has a source configured to emit coherent light of multiple wavelengths. Moreover, the apparatus comprises a measuring head configured to be contactlessly positioned adjacent the silicon wafer and configured to illuminate at least a portion of the silicon wafer with the coherent light and to receive at least a portion of radiation reflected by the silicon wafer. Additionally, the apparatus comprises a spectrometer, a beam splitter and an evaluation device. The evaluation device is configured to determine a thickness of the silicon wafer by analyzing the radiation reflected by the silicon wafer by an optical coherence tomography process. The coherent light is emitted multiple wavelengths in a bandwidth b around a central wavelength wc.

Abstract: The invention relates to an optical measuring process for acquiring a surface topography of a measurement object. To this end, a measuring device with a measuring head in a measuring head guide device is provided for chromatic confocal acquisition of the surface topography or for spectral interferometric OCT acquisition of the distance to the surface topography. Firstly, spectrally broadband light of a light source from a fibre array with i fibres of i measurement spots is directed onto the measurement object via a common measuring head optic, with formation of a spot array of i measurement spots. i reflection spectra of the i measurement channels are then acquired and digitized. Finally, the digitized reflection spectra are evaluated with removal of time variations of systematic measurement errors and time-related deviation movements of the measuring head guide device.

Abstract: A material-working device with working beams of a beam generator and with in-situ measurement of a working distance between the beam generator and a workpiece, the material-working device including a working laser; a laser scanner for the working laser, the laser scanner including a two-dimensional deflecting device with scanner mirrors and a variable refocusing device at varying working distances; and a sensor device including a spectrometer and at least one sensor light source, wherein measuring beams together scan a working area of the workpiece by the laser scanner and an objective lens while gathering the working distance, and the measuring beams of at least two of the light sources of the sensor device being linearly polarized and being coupled into a working beam path of the laser scanner of the material-working device by an optical coupling element in a collimated state with crossed polarization directions.

Abstract: Apparatus for monitoring a thickness of a silicon wafer with a highly-doped layer at least at a backside of the silicon wafer is provided. The apparatus has a source configured to emit coherent light of multiple wavelengths. Moreover, the apparatus comprises a measuring head configured to be contactlessly positioned adjacent the silicon wafer and configured to illuminate at least a portion of the silicon wafer with the coherent light and to receive at least a portion of radiation reflected by the silicon wafer. Additionally, the apparatus comprises a spectrometer, a beam splitter and an evaluation device. The evaluation device is configured to determine a thickness of the silicon wafer by analyzing the radiation reflected by the silicon wafer by an optical coherence tomography process. The coherent light is emitted multiple wavelengths in a bandwidth b around a central wavelength wc.

Abstract: According to the invention, a monitoring device (12) is created for monitoring a thinning of at least one semiconductor wafer (4) in a wet etching unit (5), wherein the monitoring device (12) comprises a light source (14), which is designed to emit coherent light of a light wave band for which the semiconductor wafer (4) is optically transparent. The monitoring device (12) further comprises a measuring head (13), which is arranged contact-free with respect to a surface of the semiconductor wafer (4) to be etched, wherein the measuring head (13) is designed to irradiate the semiconductor wafer (4) with the coherent light of the light wave band and to receive radiation (16) reflected by the semiconductor wafer (4). Moreover, the monitoring device (12) comprises a spectrometer (17) and a beam splitter, via which the coherent light of the light wave band is directed to the measuring head (13) and the reflected radiation is directed to the spectrometer (17).

Abstract: Apparatus for monitoring a thickness of a silicon wafer with a highly-doped layer at least at a backside of the silicon wafer is provided. The apparatus has a source configured to emit coherent light of multiple, wavelengths. Moreover, the apparatus comprises a measuring head configured to be contactlessly positioned adjacent the silicon wafer and configured to illuminate at least a portion of the silicon wafer with the coherent light and to receive at least a portion of radiation reflected by the silicon wafer. Additionally, the apparatus comprises a spectrometer, a beam splitter and an evaluation device. The evaluation device is configured to determine a thickness of the silicon wafer by analyzing the radiation reflected by the silicon wafer by an optical coherence tomography process. The coherent light is emitted multiple wavelengths in a bandwidth b around a central wavelength wc.

Abstract: According to the invention, a monitoring device (12) is created for monitoring a thinning of at least one semiconductor wafer (4) in a wet etching unit (5), wherein the monitoring device (12) comprises a light source (14), which is designed to emit coherent light of a light wave band for which the semiconductor wafer (4) is optically transparent. The monitoring device (12) further comprises a measuring head (13), which is arranged contact-free with respect to a surface of the semiconductor wafer (4) to be etched, wherein the measuring head (13) is designed to irradiate the semiconductor wafer (4) with the coherent light of the light wave band and to receive radiation (16) reflected by the semiconductor wafer (4). Moreover, the monitoring device (12) comprises a spectrometer (17) and a beam splitter, via which the coherent light of the light wave band is directed to the measuring head (13) and the reflected radiation is directed to the spectrometer (17).

Abstract: The invention relates to a test device for testing a bonding layer between wafer-shaped samples and a test process for testing the bonding layer. The test device comprises a measuring head for an OCT process that is configured to direct an optical measuring beam at a composite comprising at least two wafer-shaped samples with a bonding layer positioned between them. An optical beam splitter is configured to divert an optical reference beam as a reference arm for distance measurements. An evaluation unit is configured to evaluate layer thickness measurements without a reference arm and distance measurements with a reference arm. An optical switch device is configured to connect and disconnect the reference arm.

Abstract: An apparatus and method for determining a depth of a region having a high aspect ratio that protrudes into a surface of a semiconductor wafer are provided. The apparatus comprises a multi-wavelength light source, a semiconductor wafer holder for holding a semiconductor wafer, a head for directing the light source onto the semiconductor wafer, a spectrometer for collecting light comprising multiple wavelengths reflected from the semiconductor wafer and analysis means for determining a depth of the region from an interference pattern of light reflected from the semiconductor wafer by performing Fourier domain optical coherence tomography.

Abstract: Apparatus for monitoring a thickness of a silicon wafer with a highly-doped layer at least at a backside of the silicon wafer is provided. The apparatus has a source configured to emit coherent light of multiple, wavelengths. Moreover, the apparatus comprises a measuring head configured to be contactlessly positioned adjacent the silicon wafer and configured to illuminate at least a portion of the silicon wafer with the coherent light and to receive at least a portion of radiation reflected by the silicon wafer. Additionally, the apparatus comprises a spectrometer, a beam splitter and an evaluation device. The evaluation device is configured to determine a thickness of the silicon wafer by analyzing the radiation reflected by the silicon wafer by an optical coherence tomography process. The coherent light is emitted multiple wavelengths in a bandwidth b around a central wavelength wc.