Therma-wave, Inc.

Therma-wave Partners

David L Willenborg

Allan Rosencwaig

Jon Opsal

Nathan Gold

Walter Lee Smith

Michael W Taylor

John Schuur

An optical measurement device is disclosed for evaluating the parameters of a sample. The device includes a polychromatic source for generating a probe beam. The probe beam is focused on the sample surface. Individual rays within the reflected probe beam are simultaneously analyzed as a function of the position within the beam to provide information at multiple wavelengths. A filter, dispersion element and a two-dimensional photodetector array may be used so that the beam may be simultaneously analyzed at multiple angles of incidence and at multiple wavelengths. A variable image filter is also disclosed which allows a selection to be made as to the size of the area of the sample to be evaluated.

Sample characteristic analysis utilizing multi wavelength and multi

Multiple angle spectroscopic analyzer utilizing interferometric and

An approach for increasing the sensitivity of a high resolution measurement device 50 is disclosed. The device includes a laser 52 for generating a probe beam 54 which is tightly focused onto the surface of the sample 58. A detector 66 is provided for monitoring a parameter of the reflected probe beam. In accordance with the subject invention, a spatial filter is provided for reducing the amount of light energy reaching the detector that has been reflected from areas on the surface of the sample beyond the focused spot. The spatial filter includes a relay lens 68 and a blocking member 70 located in the focal plane of the lens. The blocking member 70 includes an aperture 72 dimensioned to block light reflected from the surface of the sample beyond a predetermined distance from the center of the focused spot. In this manner, greater sensitivity to sample characteristics within the highly focused spot is achieved.

Optical measurement device with enhanced sensitivity

In an ellipsometric apparatus, a laser is provided for generating a probe beam. The probe beam is passed through a polarization section to give the beam a known polarization state. The probe beam is then tightly focused with a high numerical aperture lens onto the surface of the sample. The polarization state of the reflected probe beam is analyzed. In addition, the angle of incidence of one or more rays in the incident probe beam is determined based the radial position of the rays within the reflected probe beam. This approach provides enhanced spatial resolution and allows measurement over a wide spread of angles of incidence without adjusting the position of the optical components. Multiple angle of incidence measurements are greatly simplified.

High resolution ellipsometric apparatus

An apparatus (20) for measuring the thickness of a thin film layer (32) on substrate (28) includes a probe beam of radiation (24) focused substantially normal to the surface of the sample using a high numerical aperture lens (30). The high numerical aperture lens (30) provides a large spread of angles of incidence of the rays within the incident focused beam. A detector (50) measures the intensity across the reflected probe beam as a function of the angle of incidence with respect to the surface of the substrate (28) of various rays within the focused incident probe beam. A processor (52) functions to derive the thickness of the thin film layer based on these angular dependent intensity measurements. This result is achieved by using the angular dependent intensity measurements to solve the layer thickness using variations of the Fresnel equations. The invention is particularly suitable for measuring thin films, such as oxide layers, on silicon semiconductor samples.

Method and apparatus for measuring thickness of thin films

The subject invention relates to a method and apparatus for identifying and testing the location of areas of interest on a workpiece and specifically, unmasked areas on a semiconductor wafer. In the subject method, the surface of the wafer is scanned with a search beam of radiation. The power of the reflected search beam will be a function of the optical reflectivity of the surface of the sample. Since the optical reflectivity of the unmasked areas are different from the masked areas, the power measurement of the reflected search beam can be used to identify the location of areas to be measured. In the preferred testing procedure, an intensity modulated pump beam is used to periodically excite a region in the identified unmasked area. A probe beam is then directed within the periodically excited region and the periodic changes in the power of the reflected probe beam, induced by the pump beam, are measured to evaluate ion dopant concentrations or the effects of processing steps, such as etching, on the surface of the wafer.

Apparatus for locating and testing areas of interest on a workpiece

A method and apparatus is disclosed for detecting thermal waves. This system is based on the measurement of the change in reflectivity at the sample surface which is a function of the changing surface temperature. The apparatus includes a radiation probe beam that is directed on a portion of the area which is being periodically heated. A photodetector is aligned to sense the intensity changes in the reflected radiation probe beam which results from the periodic heating. These signals are processed to detect the presence of thermal waves.

Growing community of inventors

Dublin, CA, United States of America

David L Willenborg