摘要:
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). The monitoring device (12) further comprises an evaluation unit (18), wherein the evaluation unit (18) is designed to determine a thickness d(t) of the semiconductor wafer (4) from the radiation (16) reflected by the semiconductor wafer (4) during thinning of the semiconductor wafer (4) by means of a method that is selected from the group consisting of a lD-se FDOCT method, a lD-te FDOCT method and a lD-se TDOCT method.
摘要:
The invention relates to a method for measuring the depth of penetration of a laser beam (19) into a workpiece (24, 26), wherein the laser beam is focused in a focal spot (22) by means of a focusing optical unit (14) arranged in a machining head. The focal spot produces a vapor capillary (88) in the workpiece. An optical coherence tomograph (40) produces a first measurement beam (70a) and a second measurement beam (70b). The first measurement beam (70a) is directed at a first measurement point (MPa) at the base of the vapor capillary (88) in order to thereby measure a first distance (a1) between a reference point and the first measurement point (MPa). At the same time, the second measurement beam (70b) is directed at a second measurement point (MPb) on a surface (92) of the workpiece (24) which faces the machining head (14) and which is outside of the vapor capillary (88) in order to thereby measure a second distance (a2) between the reference point and the second measurement point (MPb). The depth of penetration (d) of the laser beam then results as the difference between the second distance (a2) and the first distance (a1).
摘要:
The invention relates to an optical measuring method for capturing a surface topography (1) of a measured object (2). To this end, a measuring device (3) is provided, comprising a measuring head (4) in a measuring head guiding device (5), for chromatic confocal capture of the surface topography (1) or for a spectral interferometric OCT distance measurement to the surface topography (1). Spectral light of a light source (6) is applied to the measured object (2) from a fibre array (7) comprising i fibres (8) from i measurement spots (12 to 15) via a common measuring head lens (10), forming a spot array (11) from i measurement spots (12 to 15). The i reflection spectra of the i measurement channels are then captured and digitalised. The digitalised reflection spectra are evaluated by calculating temporal variations of systematic measurement errors and temporally induced deviation movements of the measuring head guiding device (5), comprising the following steps: - capture of geometric distance values (a, b, c) of the i measurement channels and of the three-dimensional position values for the i measurement spots on a measured object surface at the time t(j); - capture of a local inclination of the measured object surface (16) relative to the measuring head (4) comprising at least three measurement spots (12, 13, 14) of a triangle (17), which are projected onto the measured object surface (16) for correction of the measurement values; - correlation of the local topographies by separating temporally induced deviation movements of the measuring head guiding device (5) by means of a three-dimensional acceleration sensor on the measuring head (4); - creation of the correct local topographies.
摘要:
The invention relates to a material-working device (1) with working beams (4) of a beam generator (5) and with in-situ measurement of the working distance (a) between the beam generator (5) and the workpiece (6). The material-working device (1) has for this purpose a working laser (13) with working beams (4). A laser scanner (14) comprising a two-dimensional deflecting device with scanner mirrors (31, 32) is arranged downstream of a working laser (13). An automatic refocusing device for varying working distances (a(t)) is provided. A sensor device (16) comprising a spectrometer (17) and at least two sensor light sources generates measuring beams (18), which by means of the laser scanner (14) and a lens system (19) jointly sense the working area (20) of the workpiece (6) while recording the workpiece distance (a). The measuring beams (18) of the sensor light sources (11, 12) are linearly polarized and are coupled by means of an optical coupling element (21) into the path of the working beam (25) of the laser scanner (14) of the material-working device (1) with crossed directions of polarization and in a collimated state.