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公开(公告)号：US10438825B2
公开(公告)日：2019-10-08
申请号：US15688751
申请日：2017-08-28
摘要： Methods and systems for performing in-situ, selective spectral reflectometry (SSR) measurements of semiconductor structures disposed on a wafer are presented herein. Illumination light reflected from a wafer surface is spatially imaged. Signals from selected regions of the image are collected and spectrally analyzed, while other portions of the image are discarded. In some embodiments, a SSR includes a dynamic mirror array (DMA) disposed in the optical path at or near a field plane conjugate to the surface of the semiconductor wafer under measurement. The DMA selectively blocks the undesired portion of wafer image. In other embodiments, a SSR includes a hyperspectral imaging system including a plurality of spectrometers each configured to collect light from a spatially distinct area of a field image conjugate to the wafer surface. Selected spectral signals associated with desired regions of the wafer image are selected for analysis.
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公开(公告)号：US10145674B2
公开(公告)日：2018-12-04
申请号：US15497033
申请日：2017-04-25
发明人： Shankar Krishnan
摘要： Methods and systems for performing optical measurements of geometric structures filled by a capillary condensation process are presented herein. Measurements are performed while the structures under measurement are treated with a flow of purge gas that includes a controlled amount of fill material. A portion of the fill material condenses onto the structures under measurement and fills openings in the structural features, spaces between structural features, small volumes such as notches, trenches, slits, contact holes, etc. The degree of saturation of vaporized material in the gaseous flow is adjusted based on the maximum feature size to be filled. In some examples, measurement data, such as spectroscopic data or image data, are collected when a structure is unfilled and when the structure is filled by capillary condensation. The collected data are combined to improve measurement performance.
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公开(公告)号：US09952140B2
公开(公告)日：2018-04-24
申请号：US13903070
申请日：2013-05-28
发明人： Haiming Wang , Shankar Krishnan
CPC分类号： G01N21/211 , G03F7/70625
摘要： Methods and systems for small angle CD metrology with a small spot size are introduced to increase measurement sensitivity while maintaining adequate throughput necessary for modern semiconductor manufacture. A small angle CD metrology system includes a small angle spectroscopic ellipsometry (SE) subsystem combined with a small angle spectroscopic reflectometry system, both operated at small angles of incidence. The small angle SE subsystem is configured to operate in a complete Mueller Matrix mode to further improve measurement sensitivity. The small angle CD metrology system includes an objective having all reflective surfaces in the light path. In some embodiments, the all-reflective objective is a Schwartzschild objective having an axicon mirror element to further reduce measurement spot size. In some embodiments, the small angle CD metrology system includes a dynamic aperture subsystem to isolate specific ranges of angles of incidence and azimuth for improved measurement sensitivity.
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公开(公告)号：US09470639B1
公开(公告)日：2016-10-18
申请号：US15014987
申请日：2016-02-03
发明人： Guorong V. Zhuang , Shankar Krishnan , Lanhua Wei , Walter Mieher , Paul Aoyagi
CPC分类号： G01N21/9501 , G01B11/0625 , G01B11/0641 , G01B2210/56 , G01N21/211 , G01N21/255 , G01N2021/213 , G01N2201/06113 , G01N2201/0683 , G01N2201/12 , G03F7/70625
摘要： Methods and systems for performing broadband spectroscopic metrology with reduced sensitivity to grating anomalies are presented herein. A reduction in sensitivity to grating anomalies is achieved by selecting a subset of available system parameter values for measurement analysis. The reduction in sensitivity to grating anomalies enables an optimization of any combination of precision, sensitivity, accuracy, system matching, and computational effort. These benefits are particularly evident in optical metrology systems having large ranges of available azimuth angle, angle of incidence, illumination wavelength, and illumination polarization. Predictions of grating anomalies are determined based on a measurement model that accurately represents the interaction between the measurement system and the periodic metrology target under measurement. A subset of available system parameter values is selected to reduce the impact of grating anomalies on measurement results. The selected subset of available system parameters is implemented on a configurable spectroscopic metrology system performing measurements.
摘要翻译： 本文介绍了对光栅异常灵敏度降低的宽带光谱测量方法和系统。 通过选择用于测量分析的可用系统参数值的子集来实现对光栅异常的灵敏度的降低。 对光栅异常的灵敏度的降低使得能够优化精度，灵敏度，精度，系统匹配和计算工作的任何组合。 在具有大范围的可用方位角，入射角，照明波长和照明偏振的光学测量系统中，这些益处特别明显。 基于精确表示测量系统和测量周期测量目标之间的相互作用的测量模型，确定光栅异常预测。 选择可用系统参数值的一个子集来减少光栅异常对测量结果的影响。 所选择的可用系统参数的子集在执行测量的可配置光谱计量系统上实现。
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公开(公告)号：US09310290B2
公开(公告)日：2016-04-12
申请号：US14745047
申请日：2015-06-19
发明人： David Y. Wang , Klaus Flock , Lawrence Rotter , Shankar Krishnan , Johannes D. de Veer , Catalin Filip , Gregory Brady , Muzammil Arain , Andrei Shchegrov
IPC分类号： G01N21/00 , G01N21/21 , G01N21/95 , G01N21/956
CPC分类号： G01N21/211 , G01B2210/56 , G01N21/9501 , G01N21/956 , G01N2021/214 , G01N2021/8848 , G01N2201/06113 , G01N2201/0636
摘要： An apparatus includes (i) a bright light source for providing an illumination beam at multiple wavelengths selectable with a range from a deep ultraviolet wavelength to an infrared wavelength, (ii) illumination optics for directing the illumination beam towards a sample at selectable sets of angles of incidence (AOI's) or azimuth angles (AZ's) and polarization states to provide spectroscopic ellipsometry, wherein the illumination optics include an apodizer for controlling a spot size of the illumination beam on the sample at each of the selectable AOI/AZ sets, (iii) collection optics for directing an output beam from the sample in response to the illumination beam at each of the selectable AOI/AZ sets and polarization states towards a detector that generates an output signal or image based on the output beam, and (v) a controller for characterizing a feature of the sample based on the output signal or image.
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公开(公告)号：US20180238814A1
公开(公告)日：2018-08-23
申请号：US15896978
申请日：2018-02-14
发明人： Noam Sapiens , Shankar Krishnan , David Y. Wang , Alexander Buettner , Kerstin Purrucker , Kevin A. Peterlinz
摘要： Methods and systems for performing spectroscopic measurements of semiconductor structures including ultraviolet, visible, and infrared wavelengths greater than two micrometers are presented herein. A spectroscopic measurement system includes a combined illumination source including a first illumination source that generates ultraviolet, visible, and near infrared wavelengths (wavelengths less than two micrometers) and a second illumination source that generates mid infrared and long infrared wavelengths (wavelengths of two micrometers and greater). Furthermore, the spectroscopic measurement system includes one or more measurement channels spanning the range of illumination wavelengths employed to perform measurements of semiconductor structures. In some embodiments, the one or more measurement channels simultaneously measure the sample throughout the wavelength range. In some other embodiments, the one or more measurement channels sequentially measure the sample throughout the wavelength range.
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公开(公告)号：US09970863B2
公开(公告)日：2018-05-15
申请号：US14833370
申请日：2015-08-24
CPC分类号： G01N21/255 , G01J3/0205 , G01J3/0208 , G01J3/18 , G01J3/2803 , G01J3/42 , G01J2003/425 , G01N21/211 , G01N21/55 , G01N21/9501 , G01N2021/213 , G01N2201/06113 , G01N2201/068
摘要： Methods and systems for performing broadband spectroscopic metrology with reduced sensitivity to focus errors are presented herein. Significant reductions in sensitivity to focus position error are achieved by imaging the measurement spot onto the detector such that the direction aligned with the plane of incidence on the wafer surface is oriented perpendicular to the direction of wavelength dispersion on the detector surface. This reduction in focus error sensitivity enables reduced focus accuracy and repeatability requirements, faster focus times, and reduced sensitivity to wavelength errors without compromising measurement accuracy. In a further aspect, the dimension of illumination field projected on the wafer plane in the direction perpendicular to the plane of incidence is adjusted to optimize the resulting measurement accuracy and speed based on the nature of target under measurement.
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公开(公告)号：US09921152B2
公开(公告)日：2018-03-20
申请号：US15336705
申请日：2016-10-27
发明人： Shankar Krishnan , David Y. Wang
IPC分类号： G01J3/40 , G01N21/3563 , G01N21/21 , G01J3/18 , G01J3/427
CPC分类号： G01N21/3563 , G01J3/0224 , G01J3/18 , G01J3/2803 , G01J3/36 , G01J3/427 , G01J2003/4275 , G01N21/211 , G01N21/31 , G01N21/9501 , G01N2021/213 , G01N2021/3568
摘要： Methods and systems for performing simultaneous spectroscopic measurements of semiconductor structures at ultraviolet, visible, and infrared wavelengths are presented herein. In another aspect, wavelength errors are reduced by orienting the direction of wavelength dispersion on the detector surface perpendicular to the projection of the plane of incidence onto the detector surface. In another aspect, a broad range of infrared wavelengths are detected by a detector that includes multiple photosensitive areas having different sensitivity characteristics. Collected light is linearly dispersed across the surface of the detector according to wavelength. Each different photosensitive area is arranged on the detector to sense a different range of incident wavelengths. In this manner, a broad range of infrared wavelengths are detected with high signal to noise ratio by a single detector. These features enable high throughput measurements of high aspect ratio structures with high throughput, precision, and accuracy.
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公开(公告)号：US20170356800A1
公开(公告)日：2017-12-14
申请号：US15344825
申请日：2016-11-07
CPC分类号： G01J3/189 , G01J3/0289 , G01J3/10 , G01J3/2803 , G01N21/255 , G01N21/27 , G01N33/00 , G01N2033/0095
摘要： Methods and systems for performing simultaneous spectroscopic measurements of semiconductor structures over a broad range of angles of incidence (AOI), azimuth angles, or both, are presented herein. Spectra including two or more sub-ranges of angles of incidence, azimuth angles, or both, are simultaneously measured over different sensor areas at high throughput. Collected light is linearly dispersed across different photosensitive areas of one or more detectors according to wavelength for each subrange of AOIs, azimuth angles, or both. Each different photosensitive area is arranged on the one or more detectors to perform a separate spectroscopic measurement for each different range of AOIs, azimuth angles, or both. In this manner, a broad range of AOIs, azimuth angles, or both, are detected with high signal to noise ratio, simultaneously. This approach enables high throughput measurements of high aspect ratio structures with high throughput, precision, and accuracy.
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公开(公告)号：US20170205342A1
公开(公告)日：2017-07-20
申请号：US15336705
申请日：2016-10-27
发明人： Shankar Krishnan , David Y. Wang
IPC分类号： G01N21/3563 , G01J3/18 , G01J3/427 , G01N21/21
CPC分类号： G01N21/3563 , G01J3/0224 , G01J3/18 , G01J3/2803 , G01J3/36 , G01J3/427 , G01J2003/4275 , G01N21/211 , G01N21/31 , G01N21/9501 , G01N2021/213 , G01N2021/3568
摘要： Methods and systems for performing simultaneous spectroscopic measurements of semiconductor structures at ultraviolet, visible, and infrared wavelengths are presented herein. In another aspect, wavelength errors are reduced by orienting the direction of wavelength dispersion on the detector surface perpendicular to the projection of the plane of incidence onto the detector surface. In another aspect, a broad range of infrared wavelengths are detected by a detector that includes multiple photosensitive areas having different sensitivity characteristics. Collected light is linearly dispersed across the surface of the detector according to wavelength. Each different photosensitive area is arranged on the detector to sense a different range of incident wavelengths. In this manner, a broad range of infrared wavelengths are detected with high signal to noise ratio by a single detector. These features enable high throughput measurements of high aspect ratio structures with high throughput, precision, and accuracy.
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