Abstract: Embodiments of the present invention recite a method and system for fabricating a data storage medium. In one embodiment, a detectable pattern is created at the surface of a substrate. An electron beam lithography process is then initiated upon the substrate.

Abstract: A contact magnetic transfer (CMT) master template with antiferromagnetically-coupled (AF-coupled) magnetic islands is used for transferring a magnetic pattern, such as a servo pattern, to a magnetic recording disk. The template is a rigid or flexible substrate with each magnetic island being two ferromagnetic films antiferromagnetically-coupled by an antiferromagnetically-coupling (AFC) film. In the presence of the applied magnetic field the magnetic moments of the two ferromagnetic films are parallel and substantially identical so they generate a magnetic field that cancels the applied field in the region of the slave disk facing the islands. However, when the applied field is removed, any residual magnetization results in the remanent moments in the two ferromagnetic films being oriented antiparallel as a result of the antiferromagnetic exchange coupling across the AFC film. Thus the islands have no net remanent magnetic moment that can affect the servo pattern transferred to the recording disk.

Abstract: A system for tracking and segregating repeated defects on media disks as tabled data in disk drives is disclosed. The disks have the same defects as the sub-master from which they are formed. Likewise, the sub-masters have the same defects as the master from which they are formed which, in turn, are passed down to the disks themselves. This information is recorded in the disk drives to avoid read/write operations in the affected sectors of the disks. In addition, the order and production quantities of sub-masters and disks made are tracked since replication performance decays over time.

Abstract: A magnetic recording disk drive has disks with identical pre-patterned servo patterns on their front and back surfaces and a servo control system for positioning the read/write heads using the servo signals from the identical servo patterns. The servo sectors on the two disk surfaces form identical patterns of angularly spaced arcuate-shaped lines that extend generally radially across the data tracks. The arcuate-shaped lines on one surface, the front surface, generally replicate the path of the recording head as it is moved across the data tracks by a rotary actuator, so that there is a constant sampling rate of the servo sectors on the front surface regardless of radial position of the head. However, the arcuate-shaped lines on the other surface, the back surface, do not replicate the path of the recording head so the servo sampling rate is not constant but varies with radial position of the head.

Abstract: A magnetic recording disk drive has disks with identical pre-patterned servo patterns on their front and back surfaces and a servo control system for positioning the read/write heads using the servo signals from the identical servo patterns. The servo sectors on the two disk surfaces form identical patterns of angularly spaced arcuate-shaped lines that extend generally radially across the data tracks. The arcuate-shaped lines on one surface, the front surface, generally replicate the path of the recording head as it is moved across the data tracks by a rotary actuator, so that there is a constant sampling rate of the servo sectors on the front surface regardless of radial position of the head. However, the arcuate-shaped lines on the other surface, the back surface, do not replicate the path of the recording head so the servo sampling rate is not constant but varies with radial position of the head.

Abstract: A solution to the problem of long, e-beam mastering times needed for patterning masters for patterned magnetic disk media is disclosed. A process for fabrication of masters takes advantage of the circular symmetry of magnetic disks and reduces the total required mastering time by an order of magnitude over prior art processes. This process relies on e-beam mastering of one small arcuate portion of the master, and then replicating that portion around a circular path on the master several times to create a full disk master. The architecture of this design also corrects for errors in head positioning on the final patterned media disk that may be introduced by the mastering process.

Abstract: A method for patterning and forming very small structures on a substrate such as a wafer. The process uses a difference in surface energy between a mask and the substrate to selectively deposit a hard mask material such as a metal onto the surface of the substrate. The mask can be formed extremely thin, such as only an atomic mono-layer thick, and can be patterned by ion beam photolithography. The pattern can, therefore, be formed with extremely high resolution. The thin mask layer can be constructed of various materials and can be constructed of perfluoropolyether diacrylate (PDA), which can be dip coated to and exposed to form a desirable positive photoresist mask layer.

Abstract: A magnetic recording disk in a disk drive has identical pre-patterned servo patterns on its front and back surfaces. The servo patterns on each disk surface are pre-patterned with a single master template, resulting in the identical pattern on each disk surface. The servo sectors on the two disk surfaces can form identical patterns of angularly spaced arcuate-shaped lines or straight lines that extend radially across the data tracks. However, because the lines on at least one of the disk surfaces do not replicate the path of the recording head, the sampling rate of the servo sectors on that surface is not constant but varies with radial position of the head. To accommodate this, the disk drive's servo control system calculates a timing adjustment from an estimate of the radial position of the head and uses this timing adjustment to adjust the time to open a time window to allow detection of the servo sectors.

Abstract: Watermarks for patterned magnetic media. The watermarks are used to demonstrate the unauthorized replication of a patterned magnetic media. The watermarks include a dibit, a pattern in an open region, shifting of data, shifting of a sync mark and large length scale perturbations. Also described are methods to determine if a watermark appears on a patterned media.

Abstract: A method for patterning and forming very small structures on a substrate such as a wafer. The process uses a difference in surface energy between a mask and the substrate to selectively deposit a hard mask material such as a metal onto the surface of the substrate. The mask can be formed extremely thin, such as only an atomic mono-layer thick, and can be patterned by ion beam photolithography. The pattern can, therefore, be formed with extremely high resolution. The thin mask layer can be constructed of various materials and can be constructed of perfluorpolyether diacrylate (PDA), which can be dip coated to and exposed to form a desirable positive photoresist mask layer.

Abstract: A nanoimprinting configuration includes a UV light diffuser that randomizes a collimated UV light beam so as to diffuse the shadowing effect from any defect object that resides in the UV optical path. In addition, a combination center circular pad and outer ring-shaped pad form a donut-shaped “non-contact” area between the two pad pieces. The size and shape of the two pad combination are designed to avoid direct gel pad contact above the patterned imprint zone on the disk substrate. The purpose of the gel pad, non-contact configuration is to eliminate any possible surface deformation incurred along the loading column and thereby avoid the elastic propagation of any deformations to the stamper resist surface.

Abstract: A method is provided for forming a plurality of regions of magnetic material in a substrate having a first approximately planar surface. The method comprises the steps of fabricating projections in the first surface of the substrate, depositing onto the first surface a magnetic material in such a way that the tops of the projections are covered with magnetic material, and depositing filler material atop the substrate so produced. The filler material may then be planarized, for example by chemical-mechanical polishing. In an alternative embodiment magnetic material is deposited on a substrate and portions of it are removed, leaving islands of material. Filler material is then deposited, which may be planarized.

Abstract: A nanoimprinting configuration includes a UV light diffuser that randomizes a collimated UV light beam so as to diffuse the shadowing effect from any defect object that resides in the UV optical path. In addition, a combination center circular pad and outer ring-shaped pad form a donut-shaped “non-contact” area between the two pad pieces. The size and shape of the two pad combination are designed to avoid direct gel pad contact above the patterned imprint zone on the disk substrate. The purpose of the gel pad, non-contact configuration is to eliminate any possible surface deformation incurred along the loading column and thereby avoid the elastic propagation of any deformations to the stamper resist surface.

Abstract: A method for producing high resolution nano-imprinting masters is disclosed. The method inverts the negative features of an exposed and developed positive e-beam resist to positive features in the patterned silicon nitride layer of the nano-imprinting master. A first, oxidation resistant, mask layer is used to pattern a DLC layer deposited on the silicon nitride layer. After patterning the DLC layer, the negative features of the DLC layer are filled with deposited metal, which creates a second mask layer subsequent to the removal of the remaining DLC layer. The second mask layer is used to etch the silicon nitride layer, creating the final nano-imprinting master.

Abstract: A solution to the problem of long, e-beam mastering times needed for patterning masters for patterned magnetic disk media is disclosed. A process for fabrication of masters takes advantage of the circular symmetry of magnetic disks and reduces the total required mastering time by an order of magnitude over prior art processes. This process relies on e-beam mastering of one small arcuate portion of the master, and then replicating that portion around a circular path on the master several times to create a full disk master. The architecture of this design also corrects for errors in head positioning on the final patterned media disk that may be introduced by the mastering process.

Abstract: A method for producing high resolution nano-imprinting masters is disclosed. The method inverts the negative features of an exposed and developed positive e-beam resist to positive features in the patterned silicon nitride layer of the nano-imprinting master. A first, oxidation resistant, mask layer is used to pattern a DLC layer deposited on the silicon nitride layer. After patterning the DLC layer, the negative features of the DLC layer are filled with deposited metal, which creates a second mask layer subsequent to the removal of the remaining DLC layer. The second mask layer is used to etch the silicon nitride layer, creating the final nano-imprnting master.

Abstract: An apparatus, system, and method are disclosed for utilizing a “shadow mask” approach to fabricate servo patterns on high density patterned media. The apparatus may include a deposition mask having a plurality of apertures generated by a conventional lithographic process. Material may be deposited onto a substrate through the deposition mask apertures from at least one deposition source oriented at unique deposition angles. In this manner, each aperture may correspond to multiple deposition locations. Apertures may be precisely dimensioned and positioned to create servo pattern features from the resulting deposition locations. The deposition mask may also include a plurality of bit pattern apertures adapted to direct a material to a plurality of deposition locations on the substrate, the deposition locations forming a bit pattern concurrent with formation of a servo pattern.

Abstract: A magnetic recording disk drive uses a phase-quadrature position-error-signal (PES) pattern and a servo signal demodulator that is insensitive to clock errors and phase-misalignment errors. The disk has angularly-spaced servo sectors, with each servo sector having radially-spaced servo tracks that contain a phase-quadrature pattern of servo blocks. A first band in each servo sector contains two generally like patterns radially-spaced in the servo track with the second pattern phase-shifted 90 degrees along-the-track from the first pattern. A second band in each servo sector is spaced along-the-track from the first band and also has two patterns like those in the first band, but with the phase shift of the second pattern being in the opposite direction to the phase shift of the second pattern in the first band. The demodulator calculates the true amplitudes of the servo signal from the measured amplitudes of the servo signals from each band to thereby remove clock errors and phase-misalignment errors.

Abstract: A contact magnetic transfer (CMT) master template is made by first adhering a plastic film to a first surface of a silicon wafer. A resist pattern is then formed on the polyimide film and the polyimide is reactive-ion-etched through the resist to form recesses. The resist is removed and a chemical-mechanical-polishing (CMP) stop layer is deposited over the non-recessed regions of the polyimide, and optionally into the bottoms of the recesses. A layer of magnetic material is then deposited over the polyimide film to fill the recesses. A CMP process is then performed to remove magnetic material above the recesses and above the non-recessed regions and continued until the CMP stop layer is reached. The resulting upper surface of the polyimide film is then a continuous planar film of magnetic islands and regions of CMP stop layer material that function as the nonmagnetic regions of the template.

Abstract: A hard disk drive is provided with a transparent cover that allows the elements of the disk drive to be observed while they are in operation. The cover also can be tinted with different colors or made somewhat translucent for further differentiation. In addition, decorations and/or various patterns, such as a diffraction grating pattern, may be placed or formed on the cover, the hub, and/or the actuator to further emphasize particular aspects of the disk drive. A flashing device can also be used to accentuate the rotational motion of the disk and/or hub.