Therma-wave, Inc.

Other

Kla Tencor Corporation

The United States of America As Represented by the United States

Arist Instruments, Inc.

Therma-wave Partners

Allan Rosencwaig

Jon Opsal

Walter Lee Smith

David L Willenborg

Lanhua Wei

Lena Nicolaides

Alex Salnik

Nathan Gold

Jeffrey Thomas Fanton

Charles D Hendricks

Jackson C Koo

Clifford G Wells

Michael W Taylor

John Schuur

A modulated reflectance measurement system includes lasers for generating an intensity modulated pump beam and a UV probe beam. The pump and probe beams are focused on a measurement site within a sample. The pump beam periodically excites the measurement site and the modulation is imparted to the probe beam. For one embodiment, the wavelength of the probe beam is selected to correspond to a local maxima of the temperature reflectance coefficient of the sample. For a second embodiment, the probe laser is tuned to either minimize the thermal wave contribution to the probe beam modulation or to equalize the thermal and plasma wave contributions to the probe beam modulation.

Modulated reflectance measurement system using UV probe

Device and method for measuring complex reflectance using a light source for generating a light beam with known polarization state, a lens for focusing the beam onto a sample surface such that various rays within the focused beam create a spread of angles of incidence &#x3b8;, a waveplate for retarding one polarization state of the beam, a polarizer for generating interference between beam polarization states, and a detector with a two dimensional array of detector elements for generating intensity signals in response to the beam, wherein each detector element corresponds to a unique angle of incidence &#x3b8; and azimuthal angle &#x3c6; of the reflected beam. A processor calculates magnitude and phase values for the reflected beam by using the intensity signals corresponding to at least one incident angle &#x3b8; and a plurality of azimuthal angles &#x3c6; within the at least one incident angle &#x3b8; sufficient to enable a meaningful Fourier analysis thereof.

Beam profile complex reflectance system and method for thin film and critical dimension measurements

A method and apparatus are disclosed for evaluating relatively small periodic structures formed on semiconductor samples. In this approach, a light source generates a probe beam which is directed to the sample. In one preferred embodiment, an incoherent light source is used. A lens is used to focus the probe beam on the sample in a manner so that rays within the probe beam create a spread of angles of incidence. The size of the probe beam spot on the sample is larger than the spacing between the features of the periodic structure so some of the light is scattered from the structure. A detector is provided for monitoring the reflected and scattered light. The detector includes multiple detector elements arranged so that multiple output signals are generated simultaneously and correspond to multiple angles of incidence. The output signals are supplied to a processor which analyzes the signals according to a scattering model which permits evaluation of the geometry of the periodic structure. In one embodiment, the sample is scanned with respect to the probe beam and output signals are generated as a function of position of the probe beam spot.

Critical dimension analysis with simultaneous multiple angle of incidence measurements

A method for improving the measurement of semiconductor wafers is disclosed. In the past, the repeatability of measurements was adversely affected due to the unpredictable growth of a layer of contamination over the intentionally deposited dielectric layers. Repeatability can be enhanced by removing this contamination layer prior to measurement. This contamination layer can be effectively removed in a non-destructive fashion by subjecting the wafer to a cleaning step. In one embodiment, the cleaning is performed by exposing the wafer to microwave radiation. Alternatively, the wafer can be cleaned with a radiant heat source. These two cleaning modalities can be used alone or in combination with each other or in combination with other cleaning modalities. The cleaning step may be carried out in air, an inert atmosphere or a vacuum. Once the cleaning has been performed, the wafer can be measured using any number of known optical measurement systems.

Optical inspection equipment for semiconductor wafers with precleaning

A method for analyzing asymmetric structures (including isolated and periodic structures) includes a split detector for use in a broadband spectrometer. The split has detector has separate right and left halves. By independently measuring and comparing the right and left scattered rays, information about asymmetries can be determined.

Optical scatterometry of asymmetric lines and structures

An optical measurement system, including a reference ellipsometer and a non-contact optical measurement device, evaluates a sample having at least a partially known composition. The reference ellipsometer includes a light generator to generate a beam of quasi-monochromatic light of known wavelength and polarization, directed at a non-normal angle of incidence to interact with the sample. An analyzer creates interference between S and P polarized components of the reflected beam, the intensity of which is measured by a detector. A processor determines the polarization state using the detected intensity, and determines an optical property of the sample based upon the determined polarization state, the known wavelength, and the composition. The processor calibrates the optical measurement device, used to measure an optical parameter of the sample, by comparing the measured optical parameter from the optical measurement device to the determined optical property from the reference ellipsometer.

Thin film optical measurement system and method with calibrating ellipsometer

A method and apparatus are disclosed for accurately and repeatably determining the thickness of a thin film on a substrate. A rotating compensator ellipsometer is used which generates both 2&#x3c9; and 4&#x3c9; output signals. The 4&#x3c9; omega signal is used to provide an indication of the temperature of the sample. This information is used to correct the analysis of the thin film based on the 2&#x3c9; signal. These two different signals generated by a single device provide independent measurements of temperature and thickness and can be used to accurately analyze a sample whose temperature is unknown.

Monitoring temperature and sample characteristics using a rotating compensator ellipsometer

A method is disclosed for evaluating isolated and aperiodic structure on a semiconductor sample. A probe beam from a coherent laser source is focused onto the structure in a manner to create a spread of angles incidence. The reflected light is monitored with an array detector. The intensity or polarization state of the reflected beam as a function of radial position within the beam is measured. Each measurement includes both specularly reflected light as well as light that has been scattered from the aperiodic structure into that detection position. The resulting output is evaluated using an aperiodic analysis to determine the geometry of the structure.

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Danville, CA, United States of America

Allan Rosencwaig