International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

James Hammond Brannon

Peter Michael Baumgart

Shanlin Duan

Wai Cheung Leung

Gordon James Smith

Hal Hjalmar Ottesen

Wayne Isami Imaino

Hal Jervis Rosen

Andrew Ching Tam

Chie Ching Poon

Milton Russell Latta

Anthony Juliana

Yu Lo

Charles H Lee

Iraj Kakesh Pour

Tim Minvielle

Timothy Carl Strand

Yan Liu

Li Tang

Hang Fai Ngo

Bradley Frederick Baumgartner

John R Lankard

Jorge Daniel Colonia

Connie H Moy

Huyen D Do

A method and apparatus for estimating the flyheight of an airbearing slider in a storage device. The slider floats on an airbearing over a rotating storage disk. The storage disk includes a washboard-sequence having washboard-sections each comprising surface profile variations having a different pitch. The pitches are selected from within a range of values likely to excite an airbearing resonance of the slider as the storage disk rotates at a rated storage disk velocity. For each of the washboard-sections, a maximum amplitude of flyheight modulation of the slider resulting from the slider floating over that washboard-section is measured. A determination is made of which washboard-section caused the largest measured flyheight modulation. The washboard-section having a pitch that provides an excitation frequency (when the disk is rotated at the rated storage disk velocity) that is closest to the actual airbearing resonance frequency of the slider will produce the largest flyheight modulation. The result of this determination is used to estimate the flyheight of the slider. For example, the flyheight may be estimated using an empirical formula that relates the flyheight and the resonance frequency. Once the flyheight is estimated, a determination may be made of whether the flyheight is unsatisfactory, e.g., below a minimum flyheight or decreasing. Appropriate action may be taken when the flyheight is unsatisfactory, such as notifying the user and/or scrubbing the slider. Accordingly, catastrophic head-crash may be avoided and the useful life of the storage device extended.

Method of manufacturing an apparatus and a method for estimating the flyheight of an airbearing slider in a storage device

Method and apparatus for estimating the flyheight of an airbearing slider in a storage device

A disk for calibrating glide heads utilizes a dual-zone configuration of multiple laser melt bumps having selected heights. Averaging the PZT response over many bumps significantly narrows the response distribution, resulting in greater certainty and correlation of the PZT amplitude to bump height. The multiple calibration bumps are circumferentially arranged on a disk surface at a selected radius in a ring-like manner. A second head cleaning zone is provided near the inner diameter of the disk to provide for increased reproducibility of the PZT calibration response. The second zone is densely textured and serves to clean the glide head prior to its use in the calibration zone.

Apparatus and method for glide height calibration of disk surfaces by use of dual-zone laser texture

A bump disk for accurate glide calibration has a new type of glass laser melt bumps that give the same signal amplitudes as conventional AlMg laser melt bumps for the same bump height. The present invention provides a solution to switch the calibration bumps from AlMg to glass, and can be used in disk manufacturing lines to save 30% on the cost of hard disks from inaccurate glide certification processes. The solution is to trim or burnish away loose and/or high particles on production disks before the glide tests. This additional processing step causes the responses from the glass bumps to become very similar to those of the AlMg bumps, thereby enabling glass and AlMg disks to become materially compatible.

Disk drive laser melt bump disk for accurate glide calibration and certification processing

A carbon dioxide laser is used as a non-mechanical means for smoothing and polishing the as-cut chamfer surface at the edge of the disk. Applying laser radiation to the glass surface causes transient melting and resolidification. Due to surface tension effects, the glass resolidifies to produce a surface that is significantly smoother than it was before irradiation. If scratches or abrasive marks are present on the glass surface prior to irradiation, the irradiation process &ldquo;polishes out&rdquo; these defects as long as they are not too deep. At a wavelength near 10 &mgr;m, the penetration depth of the radiation into the glass is approximately 1 &mgr;m. Therefore, scratches and defects of this order of magnitude are eliminated. The quality of the resulting modified chamfer surface is far superior to the original mechanically ground and polished surface.

Apparatus and method for improving chamfer quality of disk edge surfaces with laser treatment

Method for laser texturing magnetic recording disk

A method and apparatus for precise measurement of pressure dependence of head fly height using transitional thermal signals is disclosed. A slider is positioned relative to a rotating a disk having at least one laser bump. Calibration data is gathered by decreasing the pressure and measuring the fly height until a contact positive TA signal is detected. A non-contact negative TA signal is then normalized using the gathered calibration data. The TA signal amplitude may then be used to ascertain the fly height and pressure for a head.

Method and apparatus for precise measurement of pressure dependence of head fly height using transitional thermal signals

A method of making a calibration disk for a laser based inspection tool (LIT) for inspecting planar surfaces is described. The calibration disk has a plurality of overlapping bumps forming a circular ring with a width of one bump. The circular ring of bumps forms a feature of a known width and position on a disk which can be used to adjust one or more LIT's to yield calibrated results. The ring of overlapping bumps is preferably formed by rotating a disk substrate under a stationary pulsing laser beam.

Method of producing a calibration disk

A laser system is described which concurrently directs highly equivalent diffracted beams derived from an initial laser beam to both sides of a substrate. The diffracted beams may be generated with sufficient energy to soften spots on the surfaces of the substrate to form texture bumps as are used on substrates for magnetic disks. The diffracted beams are generated by a multichannel acousto-optic modulator (MCAOM) having at least two channels. The crystal in the MCAOM has at least two mounting faces oriented so that the acoustic transducers mounted thereon generate acoustic fields which intersect the incident laser beam at a common angle, i.e., the Bragg angle. Energizing any of the transducers causes a corresponding first order beam to be diffracted out. Preferably the diffracted beams are generated by alternating driving signals to transducers to produce two beams with pulse intensity greater than 50% of that of the incident beam which can be directed to opposite sides of a substrate for extremely uniform texturing.

Laser system for simultaneous texturing of two sides of a substrate

A multichannel acousto-optic modulator (MCAOM) is described which uses a crystal with a plurality of mounting faces for acoustic transducers. The mounting faces are oriented so that the acoustic transducers mounted thereon generate acoustic fields which intersect the incident laser beam at a common angle, i.e., the Bragg angle. A two channel MCAOM uses two transducers. Extension to any higher number of channels follows accordingly. Energizing any of the transducers causes a corresponding first order beam to be diffracted out. Since the acoustic field for each transducer intersects the incident beam with a unique orientation, each first order beam is diffracted out on a unique axis. A system utilizing an MCAOM has electronic means for controlling the driving signals to the transducers to control each channel as required by the application. Amplitude and frequency modulation of the driving signals allows the intensity and angle of the beams to be controlled.

Multiple channel acousto-optic modulators

A calibration disk for a laser based inspection tool (LIT) for inspecting planar surfaces is described. The calibration disk has a plurality of overlapping bumps forming a circular ring with a width of one bump. The circular ring of bumps forms a feature of a known width and position on a disk which can be used to adjust one or more LIT's to yield calibrated results.

Surface inspection tool

A method and means for high-rate etching a material is disclosed including the steps of disposing a gas mixture of a fluorine-containing molecule and H.sub.2 over the surface of a material to be etched; and laser dissociating this fluorine-containing molecule in the gas mixture to cause very fast etching of the material surface. In a preferred embodiment, the fluorine-containing molecule is chosen from the group of NF.sub.3, SF.sub.6, and COF.sub.2, and the surface to be etched is unmasked silicon.

High rate laser etching technique

A method for etching a polyimide body which involves directing U.V. radiation having a wavelength between about 240 to 400 nm. onto the body is described. The radiation is continued to be applied to the body for sufficient time to cause a direct etching of the body where the radiation impinges upon the body. The method is particularly useful where the U.V. radiation is passed through a mask located between the source of the ultraviolet radiation and the body so that a radiation pattern is projected onto the body where the direct etching takes place. The etching can be caused to produce openings having a positive slope in the radiation pattern upon the polyimide layer. The advantage of the positive slope is particularly great where a coating such as a metal layer is deposited over the remaining polyimide layer having the openings therein. The positive slope allows the complete filling of the openings.

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Palo Alto, CA, United States of America

James Hammond Brannon