JP2007066504A - Method for eliminating defect of peripheral part of slider occurring in conventional machining processes - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for eliminating defects of a peripheral part of a slider which occurs in a conventional machining process. <P>SOLUTION: A method for machining a slider is disclosed. The slider may be cut into small cubes from a row bar. A clean air jet may dry the slider. A lasers guided by a water jet can finely cut the peripheral part of the slider. The end of the slider and the corner of its front end can be chamfered in a prescribe diameter. The slider can be washed with pure water and dried in a heating furnace. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a slider of a magnetic hard disk drive. More particularly, the present invention relates to the manufacture of a slider for a hard disk drive.

  A hard disk drive is a common information storage device consisting essentially of a series of rotating disks accessed by magnetic read and write elements. These data transfer elements, known as transducers, are generally carried and carried in the slider body, which is on a discrete data track formed on the disk so that it can perform read or write operations. And held in close relationship. In order to properly position the transducer relative to the disk surface, an air bearing surface (ABS) formed in the slider body provides an air flow that provides sufficient lift to "fly" the slider and transducer over the disk data track. Receive. High speed rotation of the magnetic disk generates air flow or wind flow along its surface in a direction substantially parallel to the tangential velocity of the disk. The air flow cooperates with the ABS of the slider body, which can float the slider on the rotating disk. In practice, the suspended slider is physically separated from the disk surface via this self-actuating air bearing.

  Some key objectives in the ABS structure are to fly the slider and its associated transducer as close as possible to the rotating surface, and to maintain that constant close spacing regardless of changing flying conditions That is. The height or separation distance between the air bearing slider and the rotating magnetic disk is generally defined as the flying height. In general, the attached transducer or read / write element floats only about a few nanometers on the rotating disk surface. The flying height of the slider is considered one of the most important parameters affecting the ability of the mounted read / write element to read and record on the magnetic disk. A relatively small flying height allows the transducer to achieve higher resolution between different data bit positions on the disk surface, thus improving data density and recording capacity. With the growing popularity of lightweight and compact notebook computers that utilize relatively small and more powerful disk drives, the demand for increasingly lower flying heights increases continuously.

  As shown in FIG. 1, the structure of the ABS 102, commonly known as the catamaran type slider 104, is a pair of parallel rails 106 and 108 that extend along the outer edge of the slider surface facing the disk. May be formed. Other ABS 102 arrangements have also been developed, including three or more additional rails with various surface areas and profiles. The two rails 106 and 108 generally travel along at least a portion of the length of the slider body from the leading end 110 to the trailing end 112. The leading edge 110 is defined as the end of the slider through which the rotating disk passes before traveling the length of the slider 104 toward the trailing edge 112. The tip 110 may be tapered despite the large undesirable tolerances typically associated with this machining process. The transducer or magnetic element 114 is typically mounted at a location along the rear end 112 of the slider as shown in FIG. Rails 106 and 108 form an air bearing surface on which the slider floats and provide the necessary lift when in contact with the air flow produced by the rotating disk. As the disk rotates, the wind or air flow generated travels under and between the catamaran slider rails 106 and 108. As the air flow passes under the rails 106 and 108, the air pressure between the rail and the disk increases, thus providing pressurization and lift. Catamaran-type sliders generally produce a sufficient amount of lift or positive load to lift the slider to an appropriate height on the rotating disk. In the absence of the rails 106 and 108, the large surface area of the slider body 104 will result in an excessively large air bearing surface area. In general, as the surface area of the air bearing increases, the amount of lift generated also increases. Without the rails, the resulting slider will fly far from the rotating disk, thereby abandoning all of the stated benefits of having a low flying height.

  Current slider manufacturing techniques include machining processes associated with diamond, such as slicing, grinding, lapping, and kerf cutting. In particular, the process of slicing is very important and is often performed using a diamond circular saw blade rotating at high speed with a constant supply of cooling water to reduce the temperature of the material being processed.

  During this fringing process, the edges 116 along the fritted surface are subject to machining deformations that form ridges along the edges of the slider. The amount of deformation depends on machining parameters such as feed speed, saw blade characteristics, etc., and generally ranges from 10 to 15 nanometers in height. This bump at the end of the slider can also lead to catastrophic failure at the hard disk interface if they rise above the slider ABS. This problem rises exponentially with decreasing form factor of the head of the drive, such as a slider from a pico type to a femto type.

  Another major challenge of the conventional diamond sawing process is the generation of microcracks and cracks along the end of the slider as a result of the heat generated during machining. When incorporated into the device, they will act as a starting point for crushing while the slider is subjected to thermal or mechanical shock loads. This is an undesirable disadvantage since the slider capacity increases throughout and the slider flying height decreases continuously.

  Generation of substrate particles is also an important issue that is potentially caused by microcracks and cracks at the slider edge of the substrate. These particles will be generated from the tip of the ABS and the cut end of the eye as a result of the eye cut.

  One approach to minimizing these issues is by optimizing the cutting parameters of the machine that cuts in the eye, such as feed speed, coolant flow, and spindle rotation speed. In this way, the amount of adhesion and the amount of microcracks can be reduced to some extent, but as a result of the cutting mechanism, there will always be a certain amount of deformation and cracks that can never be eliminated.

  In an alternative method, the laser is directed to applying heat to the end 116 of the slider that cuts into the crevices, thus changing the stress level as a result of the slider end ridge moving downstream from the slider ABS. . This process also changes the curvature of the slider at both the crown and the cross crown, so that the process is only relative to the slider bulge if the curvature required by the slider is greater than the curvature of the bulge. Can be corrected. With advances in ABS structure, the flying height will become nearly independent of the curvature of the slider, or it may be possible to require a slider without any curvature. Furthermore, this technique does not pay attention to the generation of particles due to the tip that can be the source of the particles to be removed. Another technique changes the curvature of the slider 104 by heating the back of the slider with a laser to change the curvature of the slider and also changing the ridge at the end of the slider downstream from the ABS surface.

  Most of the techniques described above use a conventional continuous or pulsed laser to remove the slider material. One of the major challenges associated with these lasers is the amount of local heat generated. This heat will further cause micro cracks and cracks at the edges that can lead to material relocation and spread catastrophic failure at the drive level.

  As mentioned above, the process of cutting in a cross-cut is an important stage in slider manufacturing because it is the final machining stage of the manufacturing line before the head gimbal assembly (HGA) manufacturing process begins. As shown in FIG. 2, the scissors cutting leaves mechanical strain and deformation 202 along the end 116 of the air bearing surface (ABS) 102. These deformations 202 can result in the accumulation of compressive force at the ABS 102 due to preceding processes such as lapping. As the storage density of the disk increases continuously, the demand for flying closer to the disk surface relative to the slider also increases. If the deformation 202 occurs above the ABS at the slider end 116, this will lead to catastrophic failure in the disk drive.

  A method for machining a slider is disclosed. In one embodiment, a laser guided by a water jet may cut the row bar from the wafer and the slider from the row bar. A clean air jet may dry the slider. A water jet guide type laser may finely grind the peripheral portion of the slider. You may chamfer the edge part of a slider and the corner | angular part of a front-end | tip part to a predetermined radius. The slider is washed with pure water and then dried in a heating furnace.

  FIG. 3 illustrates in flowchart form one method for machining a slider according to an embodiment of the present invention. The process begins by placing a rover in a holder or part off tool 402 as shown in FIG. 4 (block 305). A rover may be fabricated from a composite of AlTiC. A conventional diamond saw may be used to crease the rover into the slider (block 310). As previously shown in FIG. 2, this method typically results in ridges on the order of 20 to 40 micrometers from the ABS pad toward the slider end and about 12 micrometers in height. After cutting the crease, the slider may be dried using a clean air jet (block 315).

  As shown in FIG. 5a, separate sliders 104 may remain in the holder 402 when the laser 502 is used to finely grind the entire periphery 504 of the ABS 102 of the slider 104 (block 320). . As shown in FIG. 5 b, laser 502 is guided by water jet 506. The water jet 506 may be concentrated on the slider 104 through a very small nozzle. The laser 502 may be a pulsed laser. The beam propagates through the water jet 506 and strikes the slider 104. By using a pulsed laser via the water jet 506, the cooling effect may dominate the heating effect of the laser. The water jet 506 is mainly used as an optical guide for the laser beam 502. Since the water jet cools when the laser beam ablates the material, the slider is not damaged by the introduction of heat. The curvature of the slider does not change and the end 504 is free of burrs, cracks, and cracks. As the water jet guide type laser, a SYNOVA (registered trademark) (R) micro jet (Micro-jet (registered trademark) (R)) laser may be used.

  Alternatively, a water jet guided laser 502 may be used to cut the rover in the crease, allowing a kerf width 404 to cut in a narrow crease of about 30 micrometers. The kerf width 404 that cuts in the crease is the spacing between the surfaces 406 cut in the crease. Narrowing the kerf width 404 cut into the crevices allows more sliders to be packed into the rover and reduces material costs.

  The amount of fine grinding of the slider is completely dependent on the cuts of the row blocks and the form factor of the slider. As shown in FIG. 6, the slider end ridge 506 may be completely removed, resulting in a small radius of curvature 602 along the cut end 504 (block 330). Rounding the edges may reduce the possibility of particles falling from the slider during the drive operation. For this part of the process, the water jet nozzle may be expanded to 40 micrometers.

  A corner 702 formed at the tip may damage the disk during the generation of impact loads in the drive. As shown in the perspective view of FIG. 7a and the plan view of FIG. 7b, the water jet guided laser 502 may grind the corner of the tip 702 to the desired radius (block 335). Grinding operations will be incorporated into the process of cutting in the crevices, reducing the number of work steps on the production line.

  Then, the slider 104 may be cleaned using regular pure water (block 340). Then, the slider may be dried in a heating furnace (block 345). The slider 104 may then be removed from the partial tool 402 and placed in a tray for a regular manufacturing process (block 350), and the process is complete.

  FIG. 8 illustrates in a flowchart an alternative method for machining a slider according to an embodiment of the invention. The process begins by creating a path on the wafer that cuts in a square (block 805). Laser 502 may cut the wafer into a row bar (block 810). Laser 502 is guided by water jet 506 (block 815). A course that cuts into the scissors is created on the rover (block 820). The rover is placed on the holder or partial tool 402 (block 825). The water-guided laser 502 cuts the row bar into a slider (block 830). The divided slider 104 may remain on the holder 402 when the water jet guided laser 502 finely grinds the entire peripheral edge 504 of the ABS 102 of the slider 104 (block 835). A small radius of curvature 602 may be created along the fringed tip 504 to completely remove the slider end ridge 506 (block 840). A water jet guided laser 502 may grind the corner of the tip 702 to a desired radius (block 845). The slider 104 may then be removed from the partial tool 402 and placed on a tray for a regular manufacturing process (block 850), completing the process.

  FIGS. 9a-b illustrate one embodiment of the slider 104 in plan and side views. The slider substrate 902 may be made of alumina (Al2O3) to titanium carbide (TiC) having a weight ratio of 70:30. A sputtered transparent alumina primer film material 904, which is an excellent dielectric medium, may then be attached to the substrate 902. The thickness of the deposit may depend on the individual wafer structure based on different manufacturing conditions. The shielding layer 906 and read / write sensor 908 may be incorporated into the sputtered transparent alumina using conventional photolithography and electro-deposition techniques. A protective film material 910 may then be used to carefully attach the read / write sensor 908, which also serves as a dielectric medium over the head read / write sensor 908.

  FIGS. 10a to 10d illustrate the process for fabricating individual sliders from the wafer in a block diagram. In FIG. 10 a, the wafer 1002 may be cut into blocks 1004. In FIG. 10b, it is shown that the row bar 1006 may be cut from the block 1004. In FIG. 10 c, the slider 104 may be cut from the row bar 1006. In FIG. 10d, a set of sliders 104 cut from the row bar is shown.

  The material transparency of the overcoat and undercoat may result in non-uniform absorption of the laser energy and cause non-uniform cutting at the trailing edge. Laser energy absorption may be improved, for example, by using different materials such as aluminum nitride for the undercoat and protective film materials. Alternatively, the transparent alumina may be colored by changing the chemical content in order to make the transparent alumina opaque. Figures 11a to d illustrate in block form one embodiment for setting up a rover for cutting without changing the chemical content. In FIG. 11a, a path 1102 that cuts in a square is etched into the wafer 1002 before cutting. Using general machining techniques, the wafer 1002 may be etched, leaving the substrate material as the only thing to be cut. In FIG. 11 b, the path 1104 that cuts into the second square is etched into the row bar 1006. In FIG. 11 c, the path 1106 to cut through the grid is prepared by laying a piece of opaque material along the path that the laser should travel on the wafer 1002. The opaque material may be silicon or any other material, which will not adversely affect the characteristics of the slider head. In FIG. 11 d, a path 1108 that cuts through a second crease of opaque material is placed on the rover 1006.

  While several embodiments have been specifically described and described herein, it will be appreciated that modifications and variations of the present invention can be made by the above teachings and without departing from the spirit and intended scope of the invention. It is encompassed within the scope of the appended claims.

1 is a perspective view of a slider device including a known read / write head. FIG. It is a perspective view of the slider which deform | transformed by the process cut | disconnected in the eye of a well-known technique. One method for machining a slider according to an embodiment of the invention is described in a flowchart. It is a perspective view of a holder and a slider by an embodiment of the present invention. It is a perspective view of a slider and a water jet guide type laser by an embodiment of the present invention. It is a perspective view of a slider and a water jet guide type laser by an embodiment of the present invention. FIG. 4 is a side view of a slider having a chamfered end according to an embodiment of the present invention. It is the perspective view and top view of a slider which have the corner | angular part of the chamfered front-end | tip part by embodiment of this invention. It is the perspective view and top view of a slider which have the corner | angular part of the chamfered front-end | tip part by embodiment of this invention. Another method for machining a slider according to an embodiment of the invention is illustrated in the flowchart. One embodiment of the slider will be described with reference to a plan view and a side view. One embodiment of the slider will be described with reference to a plan view and a side view. The process for manufacturing individual sliders from the wafer will be described with a block diagram. The process for manufacturing individual sliders from the wafer will be described with a block diagram. The process for manufacturing individual sliders from the wafer will be described with a block diagram. The process for manufacturing individual sliders from the wafer will be described with a block diagram. One embodiment for setting up a rover to cut without changing the chemical content is described in the block diagram. One embodiment for setting up a rover to cut without changing the chemical content is described in the block diagram. One embodiment for setting up a rover to cut without changing the chemical content is described in the block diagram. One embodiment for setting up a rover to cut without changing the chemical content is described in the block diagram.

Explanation of symbols

102 Air bearing surface (ABS)
DESCRIPTION OF SYMBOLS 104 Slider 502 Laser 504 Peripheral part 506 Water jet 904 Undercoat film material 908 Read / write sensor 910 Protective film material 1002 Wafer 1006 Rover 1102 The path | route which cut | disconnects to the eye of a crease

Claims (18)

A method,
Cutting the slider from the rover using a laser to the crease;
Finely grinding the peripheral edge of the slider using a laser;
Guiding the laser with a water jet.   The method of claim 1, wherein the rover has a transparent protective film.   The method of claim 2, further comprising directing a path to a transparent overcoat to facilitate laser eye cutting.   The method of claim 2, further comprising laying a path of opaque material in the rover to facilitate laser cutting of the scissors.   3. The method of claim 2, further comprising the step of coloring a transparent overcoat to create an opaque path for facilitating laser scissors cutting.   The method according to claim 2, wherein the transparent protective film is transparent alumina.   The method of claim 1, wherein the protective film is opaque.   The method of claim 1, further comprising cutting a row bar from the wafer using a laser.   The method of claim 1, wherein the rover has a transparent primer film. A slider manufacturing system,
A laser for cutting the slider from the rover into fine grains and finely grinding the peripheral edge of the slider;
A slider manufacturing system comprising a water jet for guiding a laser.   The slider manufacturing system according to claim 10, wherein the rover has a transparent protective film.   The slider manufacturing system according to claim 11, further comprising an etching tool for instructing a path to a transparent protective film in order to facilitate the cutting of the laser ridges.   12. The slider manufacturing system of claim 11, further comprising an applicator for laying a path of opaque material on the row bar to facilitate laser cutting of the flaws.   12. The slider manufacturing system of claim 11, wherein the transparent protective curtain is colored to create an opaque path for facilitating laser eye cuts.   The slider manufacturing system according to claim 11, wherein the transparent protective film is transparent alumina.   The slider manufacturing system according to claim 10, wherein the protective film is opaque.   11. The slider manufacturing system according to claim 10, wherein a laser is used to cut the row bar from the wafer.   The slider manufacturing system according to claim 10, wherein the row bar has a transparent undercoat film.

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