Pixel Systems, Inc.

Other

Hoechst Celanese Corporation

General Signal Corporation

Electroglas, Inc.

Michael P Watts

John F Schipper

Robert G Ozarski

Lawrence Hendler

David W Myers

Raul V Tan

Thiloma I Perera

Richard Alan Portune

Raul Y Tan

A system includes multiple optical Fourier transform cells which simultaneously scan a device under test. The illuminated area for each Fourier transform cell is small to provide high resolution, while the number of cells is large to cover a relatively wide area and keep inspection speed high. The advantages of optical computing performed by Fourier transform optics also keeps the inspection speed high because illuminated areas are large when compared to the resolution and Fourier transforms are linear shift invariant so that optical measurements can be performed during scanning. In one embodiment, Fourier transform cells are offset from each other perpendicular to the scan direction by less that the width of an illuminated area. This provides complete coverage during scanning of a device under test. Because the illumination for the Fourier transform is collimated, the system is insensitive to focusing errors due to fluctuations in working distance.

High-speed, high-resolution, large area inspection using multiple

A tester for testing integrated circuits-containing semiconductor wafers or substrates, includes a vertically oriented performance board with. D/A converters mounted and pin connected immediately therebehind. A prober including a vertical array of connector pins mounts a vertical probe card and a vertically-mounted chuck on which a vertically-oriented wafer or substrate is held. One of the tester and prober are moved with respect to the other to dock and latch the tester and prober together. Simultaneously the array of connector pins is electrically connected to electrical connectors on the performance board and probe needles extending from a probe board on the probes are placed into test contact with contact pads on the integrated circuits on the wafer or substrate.

Prober and tester with contact interface for integrated

High speed pattern and defect detection in flat panel displays, integrated circuits, photo mask reticles, CRT color masks, printed circuit boards, and any other patterned devices, regular or irregular, uses analog optical computing. Using appropriate illumination and optics, the Fourier transform of the image of a device under test is formed. The Fourier transform components of an ideal pattern are compared to the Fourier transform components of a measured pattern, and differences in relative intensities of the spatial components indicate a defect. A spatial separator is used to direct different components of the Fourier transform in different directions for parallel, simultaneous measurement and analysis. Utilizing Statistical Process Control, and properly comparing the different Fourier transform components, the defect is partially classified. Optical image processing is done in real time at the speed of light. Image acquisition at video rates is not a requirement, therefore detection can be performed on the fly while scanning the device under test.

Defect detection using fourier optics and a spatial separator for

Two methods for determination of thickness of a film of known material that is mounted on one face of a solid substrate of known material are disclosed, using: (1) inversion of an optical beam reflectivity equation; or (2) determination of the film thickness that minimizes the variance of the optical beam reflectivity, computed at each of a predetermined sequence of optical beam wavelengths. Four methods for determination of the (real) refractive index of a film of known thickness mounted on a face of a solid substrate of known material are disclosed, using: (1) minimization of absolute differences of computed and measured optical beam reflectivity, summed over a sequence of known film thicknesses, for assumed values of the refractive index; (2 and 3) two iterative techniques of promote convergence of an estimate of the index to a final value of the refractive index; or (4) solution of a quadratic equation whose coefficients are slowly varying functions of the solution variable.

Method for film thickness and refractive index determination

Several methods for evaluating certain changes induced in a film of semiconductor resist material after the coat process and before or at completion of the softbake process, by monitoring thickness of and absorption by a film of resist material.

Characterization of semiconductor resist material during processing

Two methods of determination of the chemical changes induced in a film of material such as photoresist that has been exposed to electromagnetic radiation. Two methods use measurement of polarized light reflected by the film mounted on a substrate to determine a real refractive index or a complex refractive index of the film. Two other methods use measurement of polarized light by the film mounted on a (partly) transparent substrate to determine a real refractive index or a complex refractive index of the film.

Growing community of inventors

Portola Valley, CA, United States of America

Michael P Watts