Abstract: A method for measuring surface topography characterized by making multiple scans of the surface with a laser scanning unit and utilizing the multiple scans to create representations of the surface's topography. The surface topography data can also be used to calculate the compressive or tensile stress caused by a thin film applied to the surface of a semiconductor wafer. The apparatus of the present invention scans a laser beam across a surface in an x direction, and detects displacements of a reflected portion of the laser beam in a z direction. A pair of photodetectors are used to translate z direction displacements of the reflected beam into analog signals which are digitized and input into a microcomputer for analysis. The multiple scans of the surface are preferably accomplished by placing the workpiece on a pedestal which can be rotated to various angular positions.

Abstract: A method for measuring surface topography characterized by making multiple scans of the surface with a laser scanning unit and utilizing the multiple scans to create representations of the surface's topography. The surface topography data can also be used to calculate the compressive or tensile stress caused by a thin film applied to the surface of a semiconductor wafer. The apparatus of the present invention scans a laser beam across a surface in an x direction, and detects displacements of a reflected portion of the laser beam in a z direction. A pair of photodetectors are used to translate z direction displacements of the reflected beam into analog signals which are digitized and input into a microcomputer for analysis. The multiple scans of the surface are preferably accomplished by placing the workpiece on a pedestal which can be rotated to various angular positions.

Abstract: A method and apparatus for measuring the curvature of a wafer. The apparatus includes a laser head that includes multiple laser sources that each emit a laser beam, each beam having a different wavelength. A CPU selects one of the sources to emit a beam. The beam is directed through a lens within the laser head and onto a surface of a wafer. The beam is reflected from the surface of the wafer and detected by a detector. The present invention includes a motor to cause relative motion between the laser head and the wafer such that the beam scans across the surface of the wafer, relaying data to the detector and the CPU. The CPU calculates the curvature of the wafer surface using the scanned data. The CPU selects a different laser source to direct a beam having a different wavelength at the wafer surface to avoid destructive interference that may occur with previously-used wavelengths.

Abstract: A method for measuring surface topography characterized by making multiple scans of the surface with a laser scanning unit and utilizing the multiple scans to create representations of the surface's topography. The surface topography data can also be used to calculate the compressive or tensile stress caused by a thin film applied to the surface of a semiconductor wafer. The apparatus of the present invention scans a laser beam across a surface in an x direction, and detects displacements of a reflected portion of the laser beam in a z direction. A pair of photodetectors are used to translate z direction displacements of the reflected beam into analog signals which are digitized and input into a microcomputer for analysis. The multiple scans of the surface are preferably accomplished by placing the workpiece on a pedestal which can be rotated to various angular positions.

Abstract: A method and apparatus for measuring the curvature of a wafer. The apparatus includes a laser head that includes multiple laser sources that each emit a laser beam, each beam having a different wavelength. A CPU selects one of the sources to emit a beam. The beam is directed through a lens within the laser head and onto a surface of a wafer. The beam is reflected from the surface of the wafer and detected by a detector. The present invention includes a motor to cause relative motion between the laser head and the wafer such that the beam scans across the surface of the wafer, relaying data to the detector and the CPU. The CPU calculates the curvature of the wafer surface using the scanned data. The CPU selects a different laser source to direct a beam having a different wavelength at the wafer surface to avoid destructive interference that may occur with previously-used wavelengths.

Abstract: A method and apparatus for finding wafer index marks and centers. A wafer having a flat or notch along its edge is placed on a rotatable platform so that a portion of the wafer's edge is positioned within a sensor assembly. The wafer is rotated, and the sensor reads the distance from the center of rotation to the edge of the wafer. This distance is measured at several angles of the wafer and the data is stored in a digital computer as a series of datapoints including an angle and a distance. A computer-implemented process calculates various geometries concerning the wafer including the location of the index mark and the center of the wafer.

Abstract: A method for measuring surface topography characterized by making multiple scans of the surface with a laser scanning unit and utilizing the multiple scans to create representations of the surface's topography. The surface topography data can also be used to calculate the compressive or tensile stress caused by a thin film applied to the surface of a semiconductor wafer. The apparatus of the present invention scans a laser beam across a surface in an x direction, and detects displacements of a reflected portion of the laser beam in a z direction. A pair of photodetectors are used to translate z direction displacements of the reflected beam into analog signals which are digitized and input into a microcomputer for analysis. The multiple scans of the surface are preferably accomplished by placing the workpiece on a pedestal which can be rotated to various angular positions.

Abstract: A method for measuring surface topography characterized by making multiple scans of the surface with a laser scanning unit and utilizing the multiple scans to create representations of the surface's topography. The surface topography data can also be used to calculate the compressive or tensile stress caused by a thin film applied to the surface of a semiconductor wafer. The apparatus of the present invention scans a laser beam across a surface in an x direction, and detects displacements of a reflected portion of the laser beam in a z direction. A pair of photodetectors are used to translate z direction displacements of the reflected beam into analog signals which are digitized and input into a microcomputer for analysis. The multiple scans of the surface are preferably accomplished by placing the workpiece on a pedestal which can be rotated to various angular positions.