公开(公告)号：US20050099627A1

公开(公告)日：2005-05-12

申请号：US11016148

申请日：2004-12-17

申请人： Guoheng Zhao ,  Kenneth Gross ,  Rodney Smedt ,  Mehrdad Nikoonahad

发明人： Guoheng Zhao ,  Kenneth Gross ,  Rodney Smedt ,  Mehrdad Nikoonahad

IPC分类号： G01B11/00 ,  G01J4/00

CPC分类号： G01N21/21 ,  G01B11/00 ,  G01N21/4788 ,  G01N21/956

摘要： A periodic structure is illuminated by polychromatic electromagnetic radiation. Radiation from the structure is collected and divided into two rays having different polarization states. The two rays are detected from which one or more parameters of the periodic structure may be derived. In another embodiment, when the periodic structure is illuminated by a poly chromatic electromagnetic radiation, the collected radiation from the structure is passed through a polarization element having a polarization plane. The element and the polychromatic beam are controlled so that the polarization plane of the element are at two or more different orientations with respect to the plane of incidence of the polychromatic beam. Radiation that has passed through the element is detected when the plane of polarization is at the two or more positions so that one or more parameters of the periodic structure may be derived from the detected signals. At least one of the orientations of the plane of polarization is substantially stationary when the detection takes place. To have as small a footprint as possible, one employs an optical device that includes a first element directing a polychromatic beam of electromagnetic radiation to the structure and a second optical element collecting radiation from the structure where the two elements form an integral unit or are attached together to form an integrated unit. To reduce the footprint, the measurement instrument and the wafer are both moved. In one embodiment, both the apparatus and the wafer undergo translational motion transverse to each other. In a different arrangement, one of the two motions is translational and the other is rotational. Any one of the above-described embodiments may be included in an integrated processing and detection apparatus which also includes a processing system processing the sample, where the processing system is responsive to the output of any one of the above embodiments for adjusting a processing parameter.

公开(公告)号：US06804003B1

公开(公告)日：2004-10-12

申请号：US09405716

申请日：1999-09-24

申请人： Haiming Wang ,  Patrick M. Maxton ,  Kenneth C. Johnson ,  Mehrdad Nikoonahad

发明人： Haiming Wang ,  Patrick M. Maxton ,  Kenneth C. Johnson ,  Mehrdad Nikoonahad

IPC分类号： G01J400

CPC分类号： G01J3/447 ,  G01B11/0641 ,  G01J4/02 ,  G01N21/21 ,  G01N21/211

摘要： Two phase modulators or polarizing elements are employed to modulate the polarization of an interrogating radiation beam before and after the beam has been modified by a sample to be measured. Radiation so modulated and modified by the sample is detected and up to 25 harmonics may be derived from the detected signal. The up to 25 harmonics may be used to derive ellipsometric and system parameters, such as parameters related to the angles of fixed polarizing elements, circular deattenuation, depolarization of the polarizing elements and retardances of phase modulators. A portion of the radiation may be diverted for detecting sample tilt or a change in sample height. A cylindrical objective may be used for focusing the beam onto the sample to illuminate a circular spot on the sample. The above-described self-calibrating ellipsometer may be combined with another optical measurement instrument such as a polarimeter, a spectroreflectometer or another ellipsometer to improve the accuracy of measurement and/or to provide calibration standards for the optical measurement instrument. The self-calibrating ellipsometer as well as the combined system may be used for measuring sample characteristics such as film thickness and depolarization of radiation caused by the sample.

摘要翻译： 采用两相调制器或偏振元件来调制光束已被待测样品修改之前和之后的询问辐射束的极化。 检测由样本调制和修改的辐射，并且可以从检测到的信号导出多达25个谐波。 可以使用多达25个谐波来导出椭偏和系统参数，例如与固定偏振元件的角度相关的参数，圆形去衰减，偏振元件的去极化和相位调制器的延迟。 可以转移一部分辐射以检测样品倾斜或样品高度的变化。 可以使用圆柱形物镜将光束聚焦到样品上以照亮样品上的圆形斑点。 上述自校准椭偏仪可以与另一种光学测量仪器如偏振计，分光光度计或其他椭偏仪组合，以提高测量精度和/或为光学测量仪器提供校准标准。 自校准椭偏仪以及组合系统可用于测量样品特性，如样品的膜厚度和辐射的去极化。

公开(公告)号：US06753528B1

公开(公告)日：2004-06-22

申请号：US10125820

申请日：2002-04-18

申请人： Mehrdad Nikoonahad ,  Guoheng Zhao

发明人： Mehrdad Nikoonahad ,  Guoheng Zhao

IPC分类号： G01N2117

CPC分类号： B81C99/005

摘要： A surface of the component in MEMS is illuminated by an illumination beam and the reflected beam is collected and detected by a position sensitive detector or photo detector array. As the surface is tilted about a pivot or about X and Y axes, the change in position of the collected beam is detected for characterizing the mechanical and optical properties of MEMS.

摘要翻译： MEMS中的部件的表面被照明光束照射，并且通过位置敏感检测器或光电检测器阵列收集和检测反射光束。 当表面绕枢轴或约X轴和Y轴倾斜时，检测收集的光束的位置变化，以表征MEMS的机械和光学性质。

公开(公告)号：US06611330B2

公开(公告)日：2003-08-26

申请号：US09778245

申请日：2001-02-06

申请人： Shing Lee ,  Haiming Wang ,  Adam Norton ,  Mehrdad Nikoonahad

发明人： Shing Lee ,  Haiming Wang ,  Adam Norton ,  Mehrdad Nikoonahad

IPC分类号： G01N2121

CPC分类号： G01J4/02 ,  G01J3/447 ,  G01N21/21

摘要： A polarized sample beam of broadband radiation is focused onto the surface of a sample and the radiation modified by the sample is collected by means of a mirror system in different planes of incidence. The sample beam focused to the sample has a multitude of polarization states. The modified radiation is analyzed with respect to a polarization plane to provide a polarimetric spectrum. Thickness and refractive information may then be derived from the spectrum. Preferably the polarization of the sample beam is altered only by the focusing and the sample, and the analyzing is done with respect to a fixed polarization plane. In the preferred embodiment, the focusing of the sample beam and the collection of the modified radiation are repeated employing two different apertures to detect the presence or absence of a birefringence axis in the sample. In another preferred embodiment, the above-described technique may be combined with ellipsometry for determining the thicknesses and refractive indices of thin films.

公开(公告)号：US5576831A

公开(公告)日：1996-11-19

申请号：US263203

申请日：1994-06-20

申请人： Mehrdad Nikoonahad ,  James A. Tebelskis

发明人： Mehrdad Nikoonahad ,  James A. Tebelskis

IPC分类号： G01N21/95 ,  G01R31/28 ,  G01R31/308 ,  H01L21/66 ,  G01B11/00

CPC分类号： G01R31/308 ,  G01N21/9501 ,  G01R31/2831 ,  H01L22/12

摘要： A surface height detection and positioning device for use in a surface inspection system. An incident beam of light impinges obliquely upon the surface, and a position detector is disposed to receive light reflected from the surface. The position detector has a sensitivity characteristic graded along a direction transverse to the surface, so that the output of the position detector is used to determine a height of the surface. The device can be incorporated into a particle detection system that scans patterned wafers with obliquely incident light to search for particles with a particle detector positioned to receive scattered light. In one embodiment, the position detector can have a width that is graded along the direction transverse to the surface, so that a scan line on the surface that is focused upon the position detector crosses the width of that detector in a time that varies as a function of the height of the surface. This time can be measured as an electrical pulse from the position detector that can be used for various purposes, including adjusting the height of the surface during scanning. In another embodiment, the position detector can have a periodic variance in light sensitivity that is graded, so that varying a height of the surface varies a phase of the output from the position detector.

摘要翻译： 一种用于表面检测系统的表面高度检测和定位装置。 入射光束倾斜地撞击在表面上，并且设置位置检测器以接收从表面反射的光。 位置检测器具有沿横向于表面的方向分级的灵敏度特性，使得位置检测器的输出用于确定表面的高度。 该装置可以结合到使用倾斜入射光扫描图案化晶片的颗粒检测系统中，以用用于接收散射光的颗粒检测器搜索颗粒。 在一个实施例中，位置检测器可以具有沿着横向于表面的方向分级的宽度，使得聚焦在位置检测器上的表面上的扫描线在随时间变化的时间内穿过该检测器的宽度 表面高度的功能。 这个时间可以被测量为来自位置检测器的电脉冲，其可以用于各种目的，包括在扫描期间调整表面的高度。 在另一个实施例中，位置检测器可以具有渐变的光敏度的周期性变化，使得改变表面的高度改变来自位置检测器的输出的相位。

公开(公告)号：US5530550A

公开(公告)日：1996-06-25

申请号：US361131

申请日：1994-12-21

申请人： Mehrdad Nikoonahad ,  Philip R. Rigg ,  Keith B. Wells ,  David S. Calhoun

发明人： Mehrdad Nikoonahad ,  Philip R. Rigg ,  Keith B. Wells ,  David S. Calhoun

IPC分类号： G01B11/02 ,  G01B11/30 ,  G01N21/88 ,  G01N21/94 ,  G01N21/95 ,  G01N21/956 ,  H01L21/66 ,  G01B11/14

CPC分类号： G01N21/9501 ,  G01N21/94 ,  G01N21/956

摘要： The position detector has a sensitivity characteristic graded along a direction transverse to the surface, so that the output of the position detector is used to determine a height of the surface. A surface height detection and positioning device for use in a surface inspection system. An incident beam of light impinges obliquely upon the surface, and a position detector is disposed to receive specularly reflected light, producing a plurality of electrical signals, with a mechanical window, defining an aperture, placed in front of the detector. The aperture's width, along the scan direction, is of sufficient size so as to create a train of signals from each of the plurality of electrical signals, having a frequency equal to the scan frequency. These electrical signals carry information responsive to both the position of reflected beam impinging on the detector and the beam's intensity and are, in turn, related to a height of the surface. To abrogate information responsive to intensity variations at the position sensitive detector, an electronic circuit is employed which determines the sum and the difference of the plurality of signals relating to wafer height and beam intensity, producing a summed signal and a difference signal respectively. The difference signal is then divided by the summed signal, thereby producing a normalized signal which represents the height of the wafer surface without regards to these reflected beam intensity variations. These signals are synchronized to the scan frequency which facilitates removing unwanted signals resulting from thermal drifts and ambient light.

摘要翻译： 位置检测器具有沿横向于表面的方向分级的灵敏度特性，使得位置检测器的输出用于确定表面的高度。 一种用于表面检测系统的表面高度检测和定位装置。 入射光束倾斜地撞击在表面上，并且位置检测器被设置成接收镜面反射光，产生多个电信号，其中机械窗口限定放置在检测器前面的孔。 沿着扫描方向的孔径的宽度具有足够的尺寸，以便产生具有等于扫描频率的频率的来自多个电信号中的每一个的一串信号。 这些电信号响应于入射在检测器上的反射光束的位置和光束的强度而携带信息，并且又与表面的高度有关。 为了消除响应于位置敏感检测器的强度变化的信息，采用电子电路，其确定与晶片高度和光束强度相关的多个信号的总和和差异，分别产生求和信号和差分信号。 然后将差分信号除以相加的信号，从而产生表示晶片表面的高度的归一化信号，而不考虑这些反射的光束强度变化。 这些信号与扫描频率同步，有助于消除由热漂移和环境光引起的不必要的信号。

公开(公告)号：US5224482A

公开(公告)日：1993-07-06

申请号：US682515

申请日：1991-04-08

申请人： Mehrdad Nikoonahad ,  Erlvada A. Sivers

发明人： Mehrdad Nikoonahad ,  Erlvada A. Sivers

IPC分类号： A61B8/06 ,  G01F1/66 ,  G01F1/708 ,  G01P5/22 ,  G01S15/58 ,  G01S15/89

CPC分类号： G01F1/66 ,  A61B8/06 ,  G01F1/7082 ,  G01S15/582 ,  G01S15/8959

摘要： An ultrasound high velocity flow measurement apparatus uses cross-correlation between consecutive echoes of coded pulses which are matched filtered at the receiver to determine velocity profiles of flowing blood. Because coded pulses are used, the interval between two pulses can be made arbitrarily small, effectively removing the peak velocity limitation.

公开(公告)号：US07375810B2

公开(公告)日：2008-05-20

申请号：US11313139

申请日：2005-12-19

申请人： Mehrdad Nikoonahad ,  Guoheng Zhao ,  Andrei V. Shchegrov ,  Ben Tsai

发明人： Mehrdad Nikoonahad ,  Guoheng Zhao ,  Andrei V. Shchegrov ,  Ben Tsai

IPC分类号： G01B11/00 ,  G06K9/00

CPC分类号： G03F7/70633 ,  G01B11/272

摘要： An overlay target with gratings thereon is illuminated and radiation scattered by the target is imaged onto detectors. A phase difference is then detected between the outputs of the detectors to find the mis-alignment error. In another aspect, an overlay target with gratings or box-in-box structures is illuminated and radiation scattered by the target is imaged onto detectors located away from the specular reflection direction of the illumination in a dark field detection scheme. Medium numerical aperture optics may be employed for collecting the radiation from the overlay target in a bright or dark field configuration so that the system has a larger depth of focus and so that the two structures of the target at different elevations can be measured accurately at the same time. Analytical functions are constructed for the grating type targets. By finding the phase difference between the two gratings at different elevations, misalignment errors can be detected. Analytical functions are constructed as a model for box-in-box type targets where data points away from the edges of the box or bars can be used in the curve fitting. Symmetrical functions are employed to further reduce noise.

摘要翻译： 其上具有光栅的覆盖目标被照射，并且由目标散射的辐射被成像到检测器上。 然后在检测器的输出之间检测到相位差，以发现错误对准误差。 在另一方面，照射具有光栅或盒内盒结构的覆盖目标，并且由暗场散射的辐射在暗场检测方案中成像到远离照明的镜面反射方向的探测器上。 可以采用中等数值孔径光学器件来收集来自覆盖目标的明亮或暗场配置的辐射，使得系统具有更大的聚焦深度，并且可以在不同高度处的靶的两个结构被精确地测量 同时。 为光栅类型目标构建分析功能。 通过在不同高度上找到两个光栅之间的相位差，可以检测到不对准误差。 分析功能被构造为盒装箱型目标的模型，其中数据指向远离箱体或杆的边缘可以在曲线拟合中使用。 采用对称功能进一步降低噪音。

公开(公告)号：US07369233B2

公开(公告)日：2008-05-06

申请号：US10718126

申请日：2003-11-19

申请人： Mehrdad Nikoonahad ,  Shing Lee ,  Hidong Kwak ,  Sergio Edelstein ,  Guoheng Zhao ,  Gary Janik

发明人： Mehrdad Nikoonahad ,  Shing Lee ,  Hidong Kwak ,  Sergio Edelstein ,  Guoheng Zhao ,  Gary Janik

IPC分类号： G01N21/17

CPC分类号： G01N21/9501 ,  G01N21/8806

摘要： In an optical system measuring sample characteristics, by reducing the amount of ambient absorbing gas or gases and moisture present in at least a portion of the illumination and detection paths experienced by vacuum ultraviolet (VUV) radiation used in the measurement process, the attenuation of such wavelength components can be reduced. Such reduction can be accomplished by a process without requiring the evacuation of all gases and moisture from the measurement system. In one embodiment, the reduction can be accomplished by displacing at least some of the absorbing gas(es) and moisture present in at least a portion of the measuring paths so as to reduce the attenuation of VUV radiation. In this manner, the sample does not need to be placed in a vacuum, thereby enhancing system throughput.

摘要翻译： 在测量样品特性的光学系统中，通过减少在测量过程中使用的真空紫外线（VUV）辐射所经历的照明和检测路径的至少一部分中存在的环境吸收气体或气体和水分的量， 可以减少波长分量。 这种还原可以通过一种方法来实现，而不需要从测量系统排出所有的气体和水分。 在一个实施例中，可以通过置换至少部分测量路径中的至少一些吸收气体和水分来实现还原，以便减少VUV辐射的衰减。 以这种方式，样品不需要放置在真空中，从而提高系统产量。

公开(公告)号：US20060290931A1

公开(公告)日：2006-12-28

申请号：US11458934

申请日：2006-07-20

申请人： Guoheng Zhao ,  Kenneth Gross ,  Rodney Smedt ,  Mehrdad Nikoonahad

发明人： Guoheng Zhao ,  Kenneth Gross ,  Rodney Smedt ,  Mehrdad Nikoonahad

IPC分类号： G01J4/00

CPC分类号： G01N21/21 ,  G01B11/00 ,  G01N21/4788 ,  G01N21/956

摘要： A periodic structure is illuminated by polychromatic electromagnetic radiation. Radiation from the structure is collected and divided into two rays having different polarization states. The two rays are detected from which one or more parameters of the periodic structure may be derived. In another embodiment, when the periodic structure is illuminated by a polychromatic electromagnetic radiation, the collected radiation from the structure is passed through a polarization element having a polarization plane. The element and the polychromatic beam are controlled so that the polarization plane of the element are at two or more different orientations with respect to the plane of incidence of the polychromatic beam. Radiation that has passed through the element is detected when the plane of polarization is at the two or more positions so that one or more parameters of the periodic structure may be derived from the detected signals. At least one of the orientations of the plane of polarization is substantially stationary when the detection takes place. To have as small a footprint as possible, one employs an optical device that includes a first element directing a polychromatic beam of electromagnetic radiation to the structure and a second optical element collecting radiation from the structure where the two elements form an integral unit or are attached together to form an integrated unit. To reduce the footprint, the measurement instrument and the wafer are both moved. In one embodiment, both the apparatus and the wafer undergo translational motion transverse to each other. In a different arrangement, one of the two motions is translational and the other is rotational. Any one of the above-described embodiments may be included in an integrated processing and detection apparatus which also includes a processing system processing the sample, where the processing system is responsive to the output of any one of the above embodiments for adjusting a processing parameter.