A subsurface inspection method and system (1) for detecting internal defects (2) and/or overlay/misalignment in a semiconductor wafer (4). A measurement laser beam (6) is split into a laser probe beam (8) and a reference laser beam (10). The laser probe beam is transmitted to a wafer surface (12). A laser excitation pulse (14) is transmitted impinging the wafer surface for causing an ultrasound wave propagating through the wafer and causing wafer surface movement when reflected back from an encountered subsurface feature. The laser probe beam and the reference laser beam are recombined in an optical interference detector (18) and the subsurface feature inside the wafer is detected by a deviation of a detected phase difference. The laser probe beam and the reference laser beam are guided through an optic (20) prior to arriving at the optical interference detector. The optic has a dispersive characteristic dimensioned to enlarge the phase difference between the reference beam and the wave length shifted probe beam.

An inspection apparatus is provided with: an irradiating device configured to irradiate a sample in which a plurality of layers are laminated with a terahertz wave; a detecting device configured to detect the terahertz wave from the sample to obtain a detected waveform; and an estimating device configured to estimate a position of a first boundary surface on the basis of a second boundary surface pulse wave and a library, the second boundary surface pulse wave appearing in the detected waveform to correspond to a second boundary surface that is farther from an outer surface than the first boundary surface, the library representing an estimated waveform of the terahertz wave from the sample.

A method for use in measuring one or more characteristics of patterned structures, the method including providing measured data comprising data indicative of at least one Raman spectrum obtained from a patterned structure under measurements using at least one selected optical measurement scheme each with a predetermined configuration of at least one of illuminating and collected light conditions corresponding to the one or more characteristics to be measured, processing the measured data, and determining, for each of the at least one Raman spectrum, a distribution of Raman-contribution efficiency (RCE) within at least a part of the structure under measurements, being dependent on characteristics of the structure and the predetermined configuration of the at least one of illuminating and collected light conditions in the respective optical measurement scheme, and analyzing the distribution of Raman-contribution efficiency and determining the one or more characteristics of the structure.

A method and system are presented for use in measuring characteristic(s) of patterned structures. The method utilizes processing of first and second measured data, wherein the first measured data is indicative of at least one Raman spectrum obtained from a patterned structure under measurements using at least one selected optical measurement scheme each with a predetermined configuration of illuminating and/or collected light conditions corresponding to the characteristic(s) to be measured, and the second measured data comprises at least one spectrum obtained from the patterned structure in Optical Critical Dimension (OCD) measurement session. The processing comprises applying model-based analysis to the at least one Raman spectrum and the at least one OCD spectrum, and determining the characteristic(s) of the patterned structure under measurements.

Methods and devices for additive manufacturing of workpieces are provided. For analysis during production, a test is carried out using a selected test method. The test results are compared with simulated test results derived during a simulation of the manufacturing and testing. The test may use one or more of a laser ultrasound test unit, an electronic laser speckle interferometry test unit, an infrared thermography test unit, or an x-ray test unit.

A method for nondestructive measurement of an underlying layer thickness includes irradiating, with a pump laser pulse, a sample to induce generation of an acoustic wave in the sample such that the acoustic wave propagates through the sample over time, where the sample includes a substrate, an underlying layer on the substrate, and an overlying layer on the underlying layer and the underlying layer is isolated from an exterior of the sample by at least the overlying layer, irradiating the sample with a probe laser pulse after irradiating the sample with the pump laser pulse, determining a reflectance variation of the sample over time, based on monitoring a variation of a reflection of the probe laser pulse from the sample over time, to generate a first graph showing a variation of reflectance of the sample over time, and determining a thickness of the underlying layer based on the first graph.

A method and system are presented for use in measuring one or more characteristics of patterned structures. The method comprises: providing measured data comprising data indicative of at least one Raman spectrum obtained from a patterned structure under measurements using at least one selected optical measurement scheme each with a predetermined configuration of at least one of illuminating and collected light conditions corresponding to the characteristic(s) to be measured; processing the measured data, and determining, for each of the at least one Raman spectrum, a distribution of Raman-contribution efficiency (RCE) within at least a part of the structure under measurements, being dependent on characteristics of the structure and the predetermined configuration of the at least one of illuminating and collected light conditions in the respective optical measurement scheme; analyzing the distribution of Raman-contribution efficiency and determining the characteristic(s) of the structure.

For a simple, fast, safe and reliable determination of the layer thickness of a bonding layer between two layers of a packaging, a laser ultrasonic method is provided, in which the transit time of the ultrasonic wave through the first and second packaging layers (2, 3) is determined in advance, and a maximum (M.sub.1, M.sub.2, M.sub.n) in the measurement signal (S) is sought, and the point in time of occurrence of this maximum (M.sub.1, M.sub.2, M.sub.n) is determined as the total transit time (T.sub.1, T.sub.2, T.sub.n) of the ultrasonic wave, and the transit time of the ultrasonic wave through the first and second packaging layers (2, 3) is subtracted from the total transit time (T.sub.1, T.sub.2, T.sub.n), and the thickness (d) of the bonding layer is deduced from the known ultrasonic speed (v.sub.S) in the bonding layer (5).

This disclosure relates to non-destructive estimation of coating layer thickness based on sweep frequency photo acoustic guided wave technique. Coating of a substrate/surface protects it from wear, corrosion and serves the cosmetic aspect, hence making coating technology is an essential part industrial process. The existing techniques for coating thickness determination are either destructive or requires a prior knowledge of the refractive index of the surface under investigation or use of sophisticated instrumentation, complicated procedure and harmful radiation during industrial deployment. The disclosure utilizes an intensity modulated Continuous Wave (CW) laser diode to excite a sample thus, making the technique a partially contact based method. Further a calibration curve is plotted by determining a frequency spectrum and resonance frequency. The calibration curve is used for estimation of a coating layer thickness.

An inspection apparatus is provided with: an irradiating device configured to irradiate a sample in which a plurality of layers are laminated with a terahertz wave; a detecting device configured to detect the terahertz wave from the sample to obtain a detected waveform; and an estimating device configured to estimate a position of a first boundary surface on the basis of a second boundary surface pulse wave and a library, the second boundary surface pulse wave appearing in the detected waveform to correspond to a second boundary surface that is farther from an outer surface than the first boundary surface, the library representing an estimated waveform of the terahertz wave from the sample.