Other

International Business Machines Corporation

Leland Stanford Junior University

Marc David Levenson

Hugo Alberto Santini

Richard Neil Zare

Rodney T Hodgson

Gary C Bjorklund

Barbara A Paldus

When rays of light converge inside a photosensitive material at angles larger than 70 degrees, one polarization of the light may fail to produce the desired image contrast in conventional exposure media. This invention describes means of suppressing the effects of the undesired polarization by using a class of photosensitive media that are insensitive to that polarization and more sensitive to the polarization conveying the desired image contrast as well as by means of optical configurations relevant in the context of semiconductor manufacturing using photolithography.

Photosensitive material for immersion photolithography

When rays of light converge inside a photosensitive material at angles larger than 70 degrees, one polarization of the light may fail to produce the desired image contrast in conventional exposure media. This invention describes a material which may be applied to a semiconductor wafer surface which ensures that the photosensitive material is exposed principally by light polarized parallel to the semiconductor wafer surface.

The interior surfaces of the holes in holey optical fibers has adsorbed optically material which may be detected by propagating laser light down the axis of the fiber and detecting Raman, Infrared, or visible fluorescence or absorption.

Detection of adsorbates on interior surfaces of holey fibers

A photolithography method and apparatus for producing minima of light intensity corresponding to a point in a phase shift mask is described. The phase shift in the light produced by the mask varies in a spiral fashion around the point so that the phase shift measured along lines drawn across the surface of the mask which pass through the point have a 180&deg; jump at the point, and lines passing around the point have no jumps between 130&deg; and 230&deg;, and most preferably no jumps between 100&deg; and 260&deg;.

Vortex phase shift mask for optical lithography

A diffusion barrier attached to the cladding layer prevents significant diffusion of a Raman active gas out of the holes in a holey fiber or photonic band gap fiber.

Diffusion barriers for holey fibers

Hollow core or &ldquo;holey&rdquo; optical fibers are filled with a gas or liquid which exhibits high Raman gain. Such gases as hydrogen and hydrogen isotopes are preferred embodiment. When these fibers are pumped with a pump laser, signals at an appropriate frequency carried by the fiber may be amplified, attenuated, changed to a different frequency, or mixed with other signals.

Holey fibers filled with raman active fluid

The fine dark features in the images projected from strong phase-shifting masks used for microdevice lithography are accompanied by 180&deg; shifts in the optical phase, produced by a topography pattern distinct from the pattern of apertures that define the bright features. A generic topography pattern can be formed on the substrate underlying a continuous opaque mask layer which subsequently is patterned with a device-specific array of apertures. When the image projected from a phase-shifting mask comprised of the generic topography pattern and the device-specific aperture pattern is combined with a device-specific image projected from an associated conventional photomask, the photoresist pattern that results corresponds to desired device layers with the imaging advantages of strong phase-shifting masks, but without the need for specific patterning of the topography pattern.

Generic phase shift masks

Generic phase shift mask

A cavity ring-down system for performing cavity ring-down spectroscopy (CRDS) using optical heterodyne detection of a ring-down wave E.sub.RD during a ring-down phase or a ring-up wave E.sub.RU during a ring up phase. The system sends a local oscillator wave E.sub.LO and a signal wave E.sub.SIGNAL to the cavity, preferably a ring resonator, and derives an interference signal from the combined local oscillator wave E.sub.LO and the ring-down wave E.sub.RD (or ring-up wave E.sub.RU). The local oscillator wave E.sub.LO has a first polarization and the ring-down wave E.sub.RD has a second polarization different from the first polarization. The system has a combining arrangement for combining or overlapping local oscillator wave E.sub.LO and the ring-down wave E.sub.RD at a photodetector, which receives the interference signal and generates a heterodyne current I.sub.H therefrom. Frequency and phase differences between the waves are adjustable.

Optical heterodyne detection for cavity ring-down spectroscopy

A method for fabricating a thin-film magnetic read/write head that eliminates contrast effects producing notching in a thin-film magnetic head coil caused by subsurface reflectivity at a reflective layer step during a photolithography step in the fabrication of the coil is provided. The method comprises the steps of forming a first permalloy yoke on a substrate, wherein the edges of the first yoke create steps from the top of the first yoke down to the substrate, forming a partial conformal layer of an electric insulation material over the first permalloy yoke and the substrate, forming a conformal copper seed layer over the electric insulation layer, forming a conductive coil on the electric insulation layer, wherein the copper coil is fabricated using a lithography process including placing a phase-shifting mask, formed in the image of the coil and containing non-printable openings covered by transparent material of a thickness that creates a 180.degree. phase-shift in illumination, over a photoresist layer, the phase-shifting mask creating illumination destructive interference in regions of the photoresist that are covered by the mask layer and immediately adjacent to regions of the photoresist not covered by the mask, forming a second electric insulation layer over the conductive coil, wherein the second electric insulation layer planarizes the coil topography, and forming a second permalloy yoke over the second electric insulation layer, wherein the second yoke is joined to the first yoke at a back gap but separated from the first yoke by a thin insulating layer at a recording gap.

Method of coil fabrication for thin-film magnetic recording heads using

Magnetic storage system using thin film magnetic recording heads using

A magneto-optical (M-O) storage detection channel which includes optical means for detecting edge transitions between magneto-optical domains. The beam returning from the storage medium is analyzed both spatially and in polarization. When a transition is centered under the read laser beam, the spatial reversal in the sign of the amplitude of the signal polarization due to the spatially nonuniform Kerr rotation is compensated by a reversal due to spatially nonuniform (split) detectors or a matched optical filter. The optical powers on the two sides of each split detectors or on two independent detectors sensitive to orthogonal polarizations become unequal thereby producing an electrical signal signal which comprises spaced peaks in opposite directions at the leading and trailing edges of the M-O domain or mark.

Magneto-optical storage system

A method and device for detecting dichroic and/or birefringent narrow spectral features in a sample is described. The method includes the steps of providing a beam of light having an optical frequency bandwidth which is narrow compared to the width of the narrow spectral feature and having a center frequency .omega..sub.c which lies near the narrow spectral feature, polarization phase modulating a beam of light with a single RF frequency to provide a pure FM spectrum having upper and lower sidebands in which either the carrier and sidebands have been polarized with respect to one another, exposing the sample containing the narrow spectral feature to the polarized modulated light so that the FM sidebands probe the narrow spectral feature, polarization analyzing and then photodetecting the light emerging from the sample to detect a RF beat at the specific RF frequency used for the polarization phase modulation, and electronically monitoring the amplitude of the RF beat signal to indicate the strength of the narrow spectral feature. The device includes a polarization phase modulator and a polarization analyzer positioned on opposite sides of the sample. In a preferred embodiment the polarization phase modulator produces a frequency modulated optical spectrum with the sidebands polarized precisely orthogonal to the carrier.

Growing community of inventors

Saratoga, CA, United States of America

Marc David Levenson