JP2005118988A - Method and device for imparting texture to gmr lapping plate by using photochemical process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and a method for manufacturing a lapping plate in lapping an air bearing surface (an air levitation surface) of a head of a GMR type. <P>SOLUTION: This lapping plate is manufactured by exposing a provided photoresist layer to the UV light via a wire mesh mask by coating a tin-antimony plate with a photoresist as one example. After development, an unetched area can be made to function as a land area for filling diamond. When using this method, an artificial object on the lapping plate can be made little, and since a dimension of a diamond particle can be further reduced, processing of a reading/writing head, particularly, a GMR head can be further improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method and apparatus for manufacturing a slider device for a hard disk drive or the like. More particularly, the present invention relates to wrapping the air bearing surface (air floating surface) of a GMR type head, among others.

  A hard disk drive is a common information storage device that consists essentially of a series of rotatable disks and to which magnetic read and write elements are accessed. These data transmission devices, commonly known as transducers, are generally supported by and embedded in a slider body. Further, the slider body is held on a separate data track formed on the disk in a relative positional relationship in close contact with it in order to be able to perform reading or writing operations. In order to properly position the transducer with respect to the disk surface, a flowing air flow that provides sufficient lift at the air bearing surface (ABS) formed on the slider body to "lift" the slider and transducer over the disk data track. Form. When the magnetic disk is rotated at a high speed, an air flow, that is, a wind flow is generated along the disk surface in a direction substantially parallel to the tangential speed of the disk. This air flow cooperates with the ABS of the slider main body, so that the slider can float on the rotating disk. In practice, the slider in the floating state is physically separated from the surface of the disk via this self-actuated air bearing. The ABS of the slider is generally formed on the slider surface facing the rotating disk and has a great influence on the ability to float the slider on the disk under various conditions.

  As shown in FIG. 1, an ABS of known design for a typical catamaran slider 5 is formed by a pair of parallel rails 2 and 4 extending along the outer edge of the slider surface facing the disk. can do. Other shapes of ABS have also been developed, including three or more additional rails, with various surface areas and geometries. In general, the two rails 2 and 4 run from the guide edge 6 to the rear edge 8 along at least part of the length of the slider body. The guide edge 6 is defined as an edge through which the rotating disk passes through the length of the slider 5 toward the rear edge 8 among the edges of the slider. As shown, the guide edge 6 can be tapered despite the large and undesired tolerances generally associated with this machining technique. The transducer or magnetic element 7 is generally mounted at a predetermined location along the rear edge 8 of the slider, as shown in FIG. Rails 2 and 4 form an air bearing surface on which the slider floats and provide the necessary lift as a result of contact with the air flow generated by the rotating disk. As the air flow passes under the rails 2 and 4, the air pressure between the rail and the disk is increased, resulting in positive pressurization and lift. Catamaran sliders typically generate a sufficient amount of lift, i.e., a positive load force, to float the slider to a suitable height above the rotating disk. If the rails 2 and 4 are not present, a very large air bearing surface area will be created due to the large surface area of the slider body 5. In general, as the air bearing surface area increases, the amount of lift generated is also increased.

  As shown in FIG. 2, the head and gimbal assembly 40 can provide a slider with multiple degrees of freedom, such as vertical space, ie, pitch and roll angles that describe the flying height of the slider. Often. As shown in FIG. 2, the suspension 74 holds the HGA 40 on the moving disk 76 (having the edge 70) and moves in the direction indicated by the arrow 80. When the disk drive shown in FIG. 2 is operated, the actuator 72 turns the HGA into an arc 78 on a disk 76 having various diameters (for example, an inner diameter (ID), an intermediate diameter (MD), and an outer diameter (OD)). Move along.

  As hard disk drives have advanced (eg, can store more than 80 gigabytes of data), giant magnetoresistive (GMR) type heads are increasingly being used. GMR heads known in the art include a plurality of components that are typically located at the rear of the slider (not the air bearing surface of the slider). These parts are very sensitive to damage induced by the head manufacturing process, especially during the lapping process. An example of wrapping and the plate used for the process is shown in US Pat. No. 4,866,886 to Holmstrand. The plate described in this patent document is rotated to polish the surface of the GMR head that contains embedded abrasive (eg, diamond particles) and is held in place on the moving plate. An abrasive slurry can be added to the plate to facilitate the polishing process. As is well known in the art, the wrapping plate includes a “land portion” and a “groove portion”. The land portion has a height larger than that of the groove portion formed on the wrapping plate, and comes into contact with the slider surface. The groove portion serves as a reservoir for abrasive particles (eg, particles in the slurry, particles originally embedded in the wrapping plate, etc.). The groove portion also serves as a reservoir for the material removed from the slider.

  When using a wrapping plate as described above, several problems can occur during the manufacture of the GMR head. The relatively large abrasive particles can damage the GMR head portion of the slider. One approach to improve head manufacturing has been to use relatively small particles in the wrapping plate. However, because the abrasive particles are smaller, controlling the flatness, texture, roughness, and cleanliness of, for example, advantageously embedded diamond abrasives (often referred to as the filling process) Becomes more difficult.

The texturing process for the wrapping plate poses a serious problem for the performance of the slider's GMR head. The texture of the wrapping plate has an adverse effect on slider performance, such as surface finish, pole tip recession (ie, PTR), dirt (ie, potentially caused device failure), and bulk removal rate. Would have.
Patent Document 1 refers to one texture processing method as described above. In this patent document, a glass bead spraying device is used to form a small cavity on the surface of the wrapping plate. When the texture processing method described in this patent document is used, the PTR can be controlled on the order of 28 μm. However, in the case of the current slider, the PTR is controlled to less than 0.01 μm. In view of this, the reason why such high numbers are obtained is that the cavity allows the abrasive sludge to move away from the surface of the disk (eg, via the centrifugal force of the rotating wrapping plate). Instead, it can act as a reservoir for the sludge. Thus, this texturing method is not acceptable for the production of current sliders.

  Another method is to form a spiral groove on the surface of the wrapping plate. The spiral groove is formed using a chamfering device. The width and spacing of the land and groove portions are referred to as the “pitch” of the wrapping plate. After forming the helical groove, the lapping plate is further processed by “deburring” (ie, cutting). When the deburring process is performed, the peak portion having a height is removed, and a land portion for filling the diamond remains. One problem with the deburring method is that it usually causes jaggedness, variability in land / groove ratio, edge breakage on flats, and variations in groove depth. In addition, these problems can adversely affect the performance of the slider after finishing directly or indirectly. One solution is to finely control the operation and function of the chamfering device, but doing so would be expensive and time consuming to implement the process.

  Yet another method for processing the wrapping plate involves using a diamond textured ring method. Unlike what is described in US Pat. No. 4,037,367 to Kruse, US Pat. No. 4,037,367, it is relatively easy for sludge to flow through the natural flow of the groove. Removal is promoted. Although the method described in this patent document can improve the bulk removal rate and pole tip retraction, the land area is not uniform in roughness and extra plate material debris can be captured in the groove. Yes and difficult to remove. In such a case, it may be difficult to fill the land region with smaller diamond particles (that is, those having an average diameter of 1.0 μm). Another disadvantage of this method is that it is limited to rigid plate materials because the amount of plate debris increases as the plate material softens.

US Pat. No. 4,866,886 U.S. Pat. No. 4,037,367

  In view of the above problems, it is necessary to provide an improved wrapping plate and a method for manufacturing a wrapping plate that reduces the fragments of the plate.

  In accordance with one aspect of the present invention, a method and apparatus for manufacturing a wrapping plate is provided. In one embodiment, the metal plate is first chemically etched using a mask-etch process known in the field of silicon chip manufacturing. The metal plate region that was not exposed to etching during this step forms a land portion, where diamond filling can be achieved. The resulting wrapping plate can be used for sensitive types of GMR heads. This is because the metal plate can be filled with relatively small diamond particles and the diamond particles are relatively uniformly distributed throughout the plate.

  Referring to FIG. 3, a flowchart of a manufacturing method according to one aspect of the present invention is shown. In this embodiment, the wrapping plate is made of an alloy of tin and antimony. At block 301, the lapping plate is machined to flatten its surface (eg, less than 2 μm roughness). Then, at block 303, the lapping plate may be polished or textured (depending on the quality of the machining process). For example, a non-jagged abrasive cloth can be used with a very fine abrasive to remove any artifacts remaining during the block 301 machining process. Thereafter, in block 305, the wrapping plate is heated in an oven (eg, at 60 ° C. for about 15 minutes). A photoresist (eg, FL13 photoresist from Shipley Company, LLC, Marlborough, Mass.) Is then deposited on the heated plate to a thickness of 30 μm. The heat remaining on the wrapping plate can assist in facilitating the work of uniformly flowing the photoresist across the surface of the plate. In addition, by heating the photoresist while pressing the laminator device used to apply the photoresist on the wrapping plate against the plate, preventing air bubbles from entering between the plate and the photoresist Can do.

  At block 309, the photoresist layer is selectively exposed for a predetermined time (eg, 8-10 seconds) (eg, against electromagnetic radiation, eg, ultraviolet light). In this embodiment, a stainless steel mesh fabric with a selected pore size and spacing is used, for example, MicroMesh from Micro Metallic, Ltd. (Mersyside, UK). Other types of masks may be used, including those used in standard photolithography processes. Using a stainless steel mesh fabric allows the exposure process to be performed more quickly and / or less expensively than standard photolithography masking. In block 311, the wrapping plate and the exposed photoresist are developed. In one embodiment, the plate is rotated at a predetermined speed, and the developer solution is dispensed over the photoresist layer through a nozzle for a predetermined time (eg, completely dissolving selected areas of the photoresist layer). The photoresist is developed by spraying for a sufficient time. At block 313, the wrapping plate is washed with deionized (DI) water to remove the developer solution and the photoresist dissolved therein. Next, the wrapping plate is dried (for example, clean air is supplied to the surface of the plate through a nozzle).

  At block 315, the wrapping plate is etched. In this embodiment using a tin-antimony alloy plate, a ratio of 1: 3 hydrochloric acid / nitric acid can be used as an etchant. Such acids can be diluted with deionized water depending on the desired value of etch depth in the plate. Accordingly, at block 315, the plate is wet etched for a predetermined time (eg, 5 minutes). In this embodiment, the lapping plate is submerged in an etchant bath and the etchant is continuously stirred so that the etch depth remains uniform throughout a predetermined area of the plate. After the etching process, the plate can be rinsed with deionized water in the same manner as described above and air dried. At block 317, the remaining photoresist is removed from the wrapping plate (eg, using an acetone solution to dissolve the undeveloped photoresist). At block 319, the wrapping plate is rinsed with deionized water in the same manner as described above and cleaned by air drying. According to another method, the lapping plate after rinsing can be dried with a suitable fabric.

  At block 321, the wrapping plate is filled with diamond particles. As noted above, this method is advantageous for wrapping a GMR head if the diamond particles have a relatively small diameter. Although diamonds having an average diameter of 100-125 nm can be used, in this example, diamonds having an average diameter of less than 50 nm are deposited with a filling device. Diamond is deposited inside the land area of the lapping plate (ie, the area of the lapping plate that has not been etched in the above process). The resulting plate can have a very uniform arrangement of small diameter diamond particles. Using a wrapping plate constructed in accordance with this aspect of the present invention, the pole tip retraction of the read / write head can be very small (eg, in the range of 2 to 3 nm), thus reducing head performance in a disk drive environment. It can be improved.

  Referring to FIGS. 4a-4l, a wrapping plate and method of processing the same are shown in accordance with one aspect of the present invention. In FIG. 4a, a metal disk (disk) 410 made of an alloy of tin and antimony is prepared. In this example, the thickness of the disc is 2.5 inches (about 6.4 cm) and the diameter is 16 inches (about 40.5 cm). In FIG. 4 b, the disk 410 is placed on the spindle motor 412 and the surface is flattened by the machining device 414. In FIG. 4c, the disk 410 is polished (eg, using the apparatus 416) with a polishing cloth that has no jagged edges. The disc can then be laminated with a photoresist. In FIG. 4 d, after the photoresist is deposited by the deposition device 418, the metal disk 410 is rotated by the spindle motor 412.

  After applying the photoresist layer 426 to the metal disk, a mask, such as a wire mesh 424, can be placed over the photoresist layer (see FIG. 4e). In this example, a portion of the photoresist layer 426 is exposed through a wire mesh 424 using a UV (ultraviolet) light source 422. The metal disk 410 can be placed on the support table 420 during this exposure process. In FIG. 4 f, the developer is dispensed onto the metal disk 410 via the device 428. As is known in the art, the developer reacts with the exposed or unexposed areas of the photoresist, depending on the type of photoresist used. In FIG. 4g, unwanted photoresist is removed, for example, by spraying deionized water onto a metal disk.

  The metal disk 410 having the developed photoresist layer 426 is etched. As can be seen in FIG. 4 h, the metal disk 410 can be lowered into the etchant 436 in the tab 438 while it is resting on the holder 434. An agitator 432 can be provided to vibrate the tab 438 to improve the etching process. In FIG. 4 i, device 440 is used to remove photoresist layer 426. In FIG. 4j, a suitable fabric 442 is used to clean the metal disk 410. In FIG. 4k, the apparatus 444 is used to fill the metal disk 410 with diamond, and diamond particles with selected dimensions are placed in the non-etched land area of the metal disk to finish the lapping plate. After the above process is completed, a wrapping plate can be used to wrap the slider, including the GMR slider held by the device 446 (see, eg, FIG. 41).

  Although the present invention has been described with reference to the above application examples, the above description of the preferred embodiments is not intended to limit the present invention. It should be understood that all aspects of the present invention are not limited to the specific drawings, forms, or dimensions described herein, but depend on various principles and modifications. It will be apparent to those skilled in the art that various changes in the form and details of the disclosed apparatus and other changes in the invention may be made by reference to the disclosure herein. . It is therefore to be understood that each claim of the appended claims is intended to cover any modifications and changes as described above in the aspects described therein, as long as they are included within the true spirit and scope of the present invention. Can be included.

  For example, although a wire mesh is used as a mask in FIG. 3 and FIGS. 4a-4l, the use of a more general mask known in the art can reduce the placement and size of land areas for diamond filling. More precise control is possible.

FIG. 3 is a perspective view of a floating slider with a read and write element assembly having a conventional catamaran air bearing slider shape with a taper. FIG. 3 is a plan view of an air bearing type slider mounted on an operating magnetic storage medium. 3 is a flow chart illustrating one method of processing a wrapping plate in accordance with an aspect of the present invention. FIG. 4 is a plan view of a wrapping plate for performing the method of FIG. 3 for processing the wrapping plate in accordance with an aspect of the present invention. FIG. 4 is a side view of an apparatus for performing the method of FIG. 3 for processing a lapping plate in accordance with an aspect of the present invention. FIG. 4 is a side view of an apparatus for performing the method of FIG. 3 for processing a lapping plate in accordance with an aspect of the present invention. FIG. 4 is a side view of an apparatus for performing the method of FIG. 3 for processing a lapping plate in accordance with an aspect of the present invention. FIG. 4 is a side view of an apparatus for performing the method of FIG. 3 for processing a lapping plate in accordance with an aspect of the present invention. FIG. 4 is a side view of an apparatus for performing the method of FIG. 3 for processing a lapping plate in accordance with an aspect of the present invention. FIG. 4 is a side view of an apparatus for performing the method of FIG. 3 for processing a lapping plate in accordance with an aspect of the present invention. FIG. 4 is a side view of an apparatus for performing the method of FIG. 3 for processing a lapping plate in accordance with an aspect of the present invention. FIG. 4 is a side view of an apparatus for performing the method of FIG. 3 for processing a lapping plate in accordance with an aspect of the present invention. FIG. 4 is a side view of an apparatus for performing the method of FIG. 3 for processing a lapping plate in accordance with an aspect of the present invention. FIG. 4 is a side view of an apparatus for performing the method of FIG. 3 for processing a lapping plate in accordance with an aspect of the present invention. FIG. 4 is a side view of an apparatus for performing the method of FIG. 3 for processing a lapping plate in accordance with an aspect of the present invention.

Explanation of symbols

2 rail 4 rail 5 catamaran type slider 6 guide edge 7 transducer 8 rear edge 410 disk 412 spindle motor

Claims (25)

A method of manufacturing a lapping plate, comprising selectively etching a metal plate, and embedding diamond particles in the metal plate. The etching step includes
The method of claim 1, comprising applying a photoresist layer to the metal plate and selectively removing the photoresist from a surface of the metal plate. Applying a photoresist layer to the metal plate,
Selectively exposing an area of the photoresist layer to electromagnetic radiation;
Developing the photoresist layer;
A method of manufacturing a wrapping plate, comprising etching a region of the metal plate, and embedding diamond particles in a non-etched region of the metal plate.   4. The method of claim 3, wherein the selective exposure step includes providing a mask between a source of ionizing radiation and the photoresist layer.   The method of claim 4, wherein the mask is a wire mesh.   The method of claim 4, wherein the ionizing radiation is ultraviolet light.   The method of claim 4, wherein the photoresist is a positive photoresist.   The method of claim 4, wherein the photoresist is a negative photoresist.   The method according to claim 4, wherein the etching process is performed by a wet etching method.   The method of claim 4, wherein the diamond particles have a diameter of less than 50 nm. Applying a photoresist layer to the metal plate,
Selectively exposing an area of the photoresist layer to electromagnetic radiation;
Developing the photoresist layer;
Etching a region of the metal plate;
A method of processing a write / read head for a disk drive, comprising embedding diamond particles in a non-etched region of the metal plate to form a wrapping plate, and wrapping a read / write head with the wrapping plate.   The method of claim 11, wherein the selective exposure step includes providing a mask between a source of ionizing radiation and the photoresist layer.   The method of claim 12, wherein the mask is a wire mesh.   The method of claim 12, wherein the ionizing radiation is ultraviolet light.   The method of claim 12, wherein the photoresist is a positive photoresist.   The method of claim 12, wherein the photoresist is a negative photoresist.   The method according to claim 12, wherein the etching process is performed by a wet etching method.   The method of claim 12, wherein the diamond particles have a diameter of less than 50 nm.   The method of claim 18, wherein the read / write head is a GMR read / write head.   The method of claim 18, wherein the pole tip retraction of the GMR read / write head is 2-3 nm. A wrapping plate comprising a metal plate including a plurality of etching regions formed by an etching process through a photoresist mask after development, and diamond particles embedded in the non-etching regions of the metal plate.   The wrapping plate of claim 21, wherein the photoresist is a positive photoresist.   The wrapping plate according to claim 21, wherein the photoresist is a negative photoresist.   The wrapping plate according to claim 21, wherein the metal plate is wet-etched.   The wrapping plate of claim 21, wherein the diamond particles have a diameter of less than 50 nm.

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