摘要:
Methods and systems for performing overlay and edge placement errors of device structures based on x-ray diffraction measurement data are presented. Overlay error between different layers of a metrology target is estimated based on the intensity variation within each x-ray diffraction order measured at multiple, different angles of incidence and azimuth angles. The estimation of overlay involves a parameterization of the intensity modulations of common orders such that a low frequency shape modulation is described by a set of basis functions and a high frequency overlay modulation is described by an affine-circular function including a parameter indicative of overlay. In addition to overlay, a shape parameter of the metrology target is estimated based on a fitting analysis of a measurement model to the intensities of the measured diffraction orders. In some examples, the estimation of overlay and the estimation of one or more shape parameter values are performed simultaneously.
摘要:
Disclosed are apparatus and methods for determining overlay error in a semiconductor target. For illumination x-rays having at least one angle of incidence (AOI), a correlation model is obtained, and the correlation model correlates overlay error of a target with a modulation intensity parameter for each of one or more diffraction orders (or a continuous diffraction intensity distribution) for x-rays scattered from the target in response to the illumination x-rays. A first target is illuminated with illumination x-rays having the at least one AOI and x-rays that are scattered from the first target in response to the illumination x-rays are collected. An overlay error of the first target is determined based on the modulation intensity parameter of the x-rays collected from the first target for each of the one or more diffraction orders (or the continuous diffraction intensity distribution) and the correlation model.
摘要:
Disclosed are apparatus and methods for performing small angle x-ray scattering metrology. This system includes an x-ray source for generating x-rays and illumination optics for collecting and reflecting or refracting a portion of the generated x-rays towards a particular focus point on a semiconductor sample in the form of a plurality of incident beams at a plurality of different angles of incidence (AOIs). The system further includes a sensor for collecting output x-ray beams that are scattered from the sample in response to the incident beams on the sample at the different AOIs and a controller configured for controlling operation of the x-ray source and illumination optics and receiving the output x-rays beams and generating an image from such output x-rays.
摘要:
Structural parameters of a specimen are determined by fitting models of the response of the specimen to measurements collected by different measurement techniques in a combined analysis. Models of the response of the specimen to at least two different measurement technologies share at least one common geometric parameter. In some embodiments, a model building and analysis engine performs x-ray and optical analyses wherein at least one common parameter is coupled during the analysis. The fitting of the response models to measured data can be done sequentially, in parallel, or by a combination of sequential and parallel analyses. In a further aspect, the structure of the response models is altered based on the quality of the fit between the models and the corresponding measurement data. For example, a geometric model of the specimen is restructured based on the fit between the response models and corresponding measurement data.
摘要:
Methods and systems for performing simultaneous optical scattering and small angle x-ray scattering (SAXS) measurements over a desired inspection area of a specimen are presented. SAXS measurements combined with optical scatterometry measurements enables a high throughput metrology tool with increased measurement capabilities. The high energy nature of x-ray radiation penetrates optically opaque thin films, buried structures, high aspect ratio structures, and devices including many thin film layers. SAXS and optical scatterometry measurements of a particular location of a planar specimen are performed at a number of different out of plane orientations. This increases measurement sensitivity, reduces correlations among parameters, and improves measurement accuracy. In addition, specimen parameter values are resolved with greater accuracy by fitting data sets derived from both SAXS and optical scatterometry measurements based on models that share at least one geometric parameter. The fitting can be performed sequentially or in parallel.
摘要:
Methods and systems for performing overlay and edge placement errors of device structures based on x-ray diffraction measurement data are presented. Overlay error between different layers of a metrology target is estimated based on the intensity variation within each x-ray diffraction order measured at multiple, different angles of incidence and azimuth angles. The estimation of overlay involves a parameterization of the intensity modulations of common orders such that a low frequency shape modulation is described by a set of basis functions and a high frequency overlay modulation is described by an affine-circular function including a parameter indicative of overlay. In addition to overlay, a shape parameter of the metrology target is estimated based on a fitting analysis of a measurement model to the intensities of the measured diffraction orders. In some examples, the estimation of overlay and the estimation of one or more shape parameter values are performed simultaneously.
摘要:
Methods and systems for performing relatively high energy X-ray Fluorescence (XRF) measurements and relatively low energy X-ray photoelectron spectroscopy (XPS) measurements over a desired inspection area of a specimen are presented. Combined XPS and XRF measurements of a specimen are achieved with illumination tailored to each respective metrology technique. A high brightness, high energy x-ray illumination source is employed in combination with one or more secondary fluorescence targets. The high energy x-ray illumination source supplies high energy x-ray illumination to a specimen to perform high energy XRF measurements. In addition, the high energy x-ray illumination source supplies high energy x-ray illumination to one or more secondary fluorescence targets. The one or more secondary fluorescence targets absorb some of the high energy x-ray photons and emit x-ray emission lines at a lower energy. The relatively low energy x-ray illumination is directed to the specimen to perform relatively low energy XPS measurements.
摘要:
Methods and systems for performing simultaneous X-ray Fluorescence (XRF) and small angle x-ray scattering (SAXS) measurements over a desired inspection area of a specimen are presented. SAXS measurements combined with XRF measurements enables a high throughput metrology tool with increased measurement capabilities. The high energy nature of x-ray radiation penetrates optically opaque thin films, buried structures, high aspect ratio structures, and devices including many thin film layers. SAXS measurements of a particular location of a planar specimen are performed at a number of different out of plane orientations. This increases measurement sensitivity, reduces correlations among parameters, and improves measurement accuracy. In addition, specimen parameter values are resolved with greater accuracy by fitting data sets derived from both SAXS and XRF measurements based on models that share at least one material parameter. The fitting can be performed sequentially or in parallel.
摘要:
Methods and systems for performing simultaneous optical scattering and small angle x-ray scattering (SAXS) measurements over a desired inspection area of a specimen are presented. SAXS measurements combined with optical scatterometry measurements enables a high throughput metrology tool with increased measurement capabilities. The high energy nature of x-ray radiation penetrates optically opaque thin films, buried structures, high aspect ratio structures, and devices including many thin film layers. SAXS and optical scatterometry measurements of a particular location of a planar specimen are performed at a number of different out of plane orientations. This increases measurement sensitivity, reduces correlations among parameters, and improves measurement accuracy. In addition, specimen parameter values are resolved with greater accuracy by fitting data sets derived from both SAXS and optical scatterometry measurements based on models that share at least one geometric parameter. The fitting can be performed sequentially or in parallel.
摘要:
Methods and systems for optimizing measurement system parameter settings of an x-ray based metrology system are presented. X-ray based metrology systems employing an optimized set of measurement system parameters are used to measure structural, material, and process characteristics associated with different semiconductor fabrication processes with greater precision and accuracy. In one aspect, a set of values of one or more machine parameters that specify a measurement scenario is refined based at least in part on a sensitivity of measurement data to a previous set of values of the one or more machine parameters. The refinement of the values of the machine parameters is performed to maximize precision, maximize accuracy, minimize correlation between parameters of interest, or any combination thereof. Refinement of the machine parameter values that specify a measurement scenario can be used to optimize the measurement recipe to reduce measurement time and increase measurement precision and accuracy.