Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/127—Structure or manufacture of heads, e.g. inductive
  • G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
  • G11B5/3163—Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
  • G11B5/3173—Batch fabrication, i.e. producing a plurality of head structures in one batch
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/10—Structure or manufacture of housings or shields for heads
  • G11B5/105—Mounting of head within housing or assembling of head and housing
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/127—Structure or manufacture of heads, e.g. inductive
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/127—Structure or manufacture of heads, e.g. inductive
  • G11B5/1274—Structure or manufacture of heads, e.g. inductive with "composite" cores, i.e. cores composed in some parts of magnetic particles and in some other parts of magnetic metal layers
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/127—Structure or manufacture of heads, e.g. inductive
  • G11B5/147—Structure or manufacture of heads, e.g. inductive with cores being composed of metal sheets, i.e. laminated cores with cores composed of isolated magnetic layers, e.g. sheets
  • G11B5/1475—Assembling or shaping of elements
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/127—Structure or manufacture of heads, e.g. inductive
  • G11B5/17—Construction or disposition of windings
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/127—Structure or manufacture of heads, e.g. inductive
  • G11B5/187—Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium; Pole pieces; Gap features
  • G11B5/1871—Shaping or contouring of the transducing or guiding surface
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/127—Structure or manufacture of heads, e.g. inductive
  • G11B5/187—Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium; Pole pieces; Gap features
  • G11B5/21—Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium; Pole pieces; Gap features the pole pieces being of ferrous sheet metal or other magnetic layers
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/127—Structure or manufacture of heads, e.g. inductive
  • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
  • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/127—Structure or manufacture of heads, e.g. inductive
  • G11B5/33—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only
  • G11B5/39—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects
  • G11B5/3903—Structure or manufacture of flux-sensitive heads, i.e. for reproduction only; Combination of such heads with means for recording or erasing only using magneto-resistive devices or effects using magnetic thin film layers or their effects, the films being part of integrated structures
  • G11B5/3967—Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read

Definitions

• thin film head technology One of the advantages of thin film head technology is that several thousand devices can be fabricated on a wafer, then processed in rows to make sliders, all in a batch process. This utilizes complex technology but less man-power resources than MIG (metal-in-the-gap) technology. Thin film head geometrical definition of gap and track widths is well controlled due to use of photolithography and vacuum deposition techniques.
• MIG metal-in-the-gap
• Yields in thin film head processing is also affected by cracking of uncured photoresist.
• Another in thin film head yield loss is due to its high throat height sensitivity. This requires a sophisticated electronic lapping guide process to improve the yield.
• MIG heads of the prior art are simpler to fabricate, less sensitive in obtaining desired throat height, and resources are plentiful in this area. But its drawbacks are that the coils are wound manually one slider at a time and the sliders are also fabricated one at a time. This non-batch fabricating process requires a heavy man-power resource. Another disadvantage is that the geometrical control, e.g., for gap and track width, is poor. This limits MIG usefulness in high density disk drives. A further limitation in regard to use in high density disk drives is due to its high magnetic inductance.
• the MIG and thin film hybrid read/write head disclosed herein combines the best of the thin film head technology with the best of the MIG technology to make high performing, high yield and lower cost heads.
• the invention utilizes the available MIG technology base and adds a batch process similar to the thin film head process. This new process is made simpler and high yielding by reducing the topography to make it a planar process. This new process does not require hard baked insulation, which further improves the yield.
• the hybrid heads of the invention are less sensitive to throat height tolerances because they use -VUG technology.
• the critical geometrical parameters e.g., gap and track, are formed in a batch process using thin film head technology and in a planar topography, resulting in better geometrical control. Because of reduced magnetic material as compared to the prior art MIG head, this hybrid head has reduced inductance.
• Another embodiment of this disclosure utilizes a MIG/thin film hybrid head for writing, and an MR head on the top of the write head for reading the data.
• the write head tilts on the top of the MR read head (at the leading end).
• the vertical distance between the read gap and the write gap determines the radius dependent skew for a rotary actuator. This distance increases when the write head is at the trailing end. This is because the transition is written closer to the trailing edge of the write pole.
• the write head (trailing) follows the read (leading) head as the disk rotates. Therefore, this head cannot read the immediately written transition.
• the inductive write head leads and the MR read head trails. That is, the MR head can read the immediately written transition.
• the written transition is closer to the MR read gap, thus reducing the radius dependent skew effect for a rotary actuator. This is a more robust design because the write head is less sensitive to change in throat height due to application of MIG technology in making a write head.
• the MR head is built first then the inductive write head is formed on the top of it.
• the MR read head is subjected to high temperature processes of thin film write head effecting the performance due to possible interdiffusion in between the layers.
• the new invention fabricates the write head first then the MR read head is formed, thus eliminating such adverse affects.
• embodiments of the presently disclosed invention teach a new and useful MIG and thin film hybrid read/write heads, and new and efficient methods of making same.
• the core fabrication and bonding with the slider is done in a batch manner. Magnetic stripes containing MIG type materials separated by glass bonding spacers are bonded on a slider-forming substrate. This bonding may be done at high temperature so that any subsequent temperature process does not effect the integrity of the bond. These magnetic stripes may be laminated MIG type material or ferrite with Sendust or high saturation material deposited thereon. Gap material and another layer of magnetic material may be deposited thereover. Then C- cuts are formed at specified intervals, with a ramp if necessary. Track width may be defined by mechanical grinding, if so desired.
• the C-cut is only part way into the magnetic stripe but the track definition may be had by removing all of the magnetic material from the track direction. All the slots and cavities may be filled with low melting glass or any non-magnetic material, and then lapped to planarize. This forms a C-core imbedded in the substrate with gap and pole-tips defined. Coil layers are formed on the planar surface separated by insulation (e.g., alumina or silicon dioxide type material). The insulating material is removed from the pole-tip and back closure regions. The top yoke (preferably of NiFe) is then formed to connect the top poletip and the back closure region of the yoke to form a complete magnetic circuit. This forms a high- quality, batch- produced inductive MIG type read/write head.
• insulation e.g., alumina or silicon dioxide type material
• the bonded magnetic stripes are formed either by bonding the magnetic stripes as discussed above or by bonding a magnetic substrate on a slider- making substrate and cutting and removing the magnetic material to form the magnetic stripes.
• the C-cut and ramp are formed by mechanical means.
• the C-cut slot is filled with low-temperature-melting glass or another non-magnetic material, and then lapped to planarize. Gap material and another layer of magnetic material is deposited.
• the poletip, back closure and alignment marks are patterned using photolithography, and the assembly is then etched to form track-width at least up to a portion into the bottom core. (Alternatively, this pattern may be made by masking with a removable type metal mask and then etching.) This makes an elevated poletip, back closure and alignment marks, all other regions being planar at lower level.
• coil layers are formed, separated by insulating material, e.g., alumina or silicon dioxide, on the planar surface.
• the MR read head is formed on the top of the write head. Bars of core, preferably laminated MIG bars separated by glass bonding material at a specified interval, are bonded on the slider- forming substrate. The thickness of the magnetic material defines the track- width.
• the C-cut and ramp are formed by mechanical means. The C-cut slot is filled with low temperature melting glass or any other non-magnetic material, and is lapped to planarize. Gap material for the write head and a layer of Sendust is deposited, and annealed. The Sendust film is then patterned to form the top pole/bottom shield of the MR read head. The MR structure with leads are formed on this shield. The write coil is formed and the yoke portion of the write head along with the top shield are deposited. The rest of the steps of forming bonding pads and encapsulation are followed in a conventional manner.
• a multi-turn yoke head is formed around a coil, with the lower pole being formed by embedding a pair of C-cut cores.
• FIG. 1A is a perspective view of a C-cut single core, the track width being shown as the thickness of the laminated magnetic (Sendust) film.
• FIG. IB is a perspective diagram of a bar containing C-cut rows.
• FIG. 2 is a perspective diagram of a slider-forming substrate showing the X-cut and Y-cut grooves.
• FIG. 3 is a diagram showing magnetic stripes separated by glass bonding/spacer stripes.
• FIG. 4 is a schematic of a slider-forming substrate and the magnetic substrates to be bonded together.
• FIG. 5 A is a schematic of a magnetic substrate and a slider-forming substrate bonded together. Magnetic material is removed in a row to form bonded magnetic stripes. C-cuts are made to form well positioned columns and rows of C-cut cores.
• FIG. 5B is a cross-sectional view taken along line A- A' of FIG. 5 A.
• FIG. 6 is a diagram showing C-cut grooves on a wafer.
• FIG. 7 is a schematic representation of an inductive head of the invention.
• FIG. 8 is a cross-sectional representation of FIG. 7 along A-A'.
• FIG. 9 is an air-bearing-surface (ABS) view (section along B- B') in FIG. 7.
• ABS air-bearing-surface
• FIG. 10A is a cross-sectional schematic showing C-cut grooves, gap layer, Sendust layer which is patterned and etched to form the top pole-tip of the inductive write head as well as the bottom shield of the MR read head.
• FIG. 1 OB is a cross-sectional schematic of an MR read head sitting on the top of the inductive write head.
• FIG 11 is a schematic of the ABS view of FIG. 10B.
• FIG. 12 is a schematic of two c-cut cores, staggered and bonded together.
• FIG. 13 is a schematic of a multi-turn yoke head formed around a coil according to the invention.
• FIG. 14 A-F is a schematic of a multi-turn yoke head formed around a coil according to the invention.
• the invention may be formed as a MIG head or a ferrite head, as discussed below.
• individual core 210, or bar 220 forms a laminated MIG core formed by depositing a soft magnetic layer, e.g, Sendust 201, separated by thin (0.1 micron) nonmagnetic material, e.g., alumina 202, on a substrate material 200.
• C-cut slots 204 are formed (and may be tapered, i.e., apex angled, forming a ramp).
• the core 210 and bar 220 are made of ferrite and Sendust type material is deposited after cutting C-cut 204.
• These cores 210 or bars 220 are bonded on a slider-forming substrate 230.
• the substrate 230 has a series of partial X- cuts 231 and Y-cuts 232 at a well defined interval.
• the bar 220 is bonded in a slot 231 such that C-cuts 204 is in an exact alignment with the slot 232.
• a glass spacer stripe and bonding material (not shown), filling the C-cut 204 and aligning the reference surface 215 of one bar with respect to another on the substrate 230, is adjusted and fused to bond the bars on the substrate.
• the substrate 230 may be lapped to planarize and expose the core surface 218 or a portion nearby.
• the bars 220 may be stacked and aligned with each other in reference to surface 215 on a slider-forming substrate and bonded and, ideally it is then lapped to planarize. This forms a planar wafer in which C-core bars are embedded, to form the bottom pole (yoke and tip).
• the gap material 235 (FIG. 8) is formed and then another layer 236 (FIG. 10A) of Sendust type material is deposited and annealed for later forming of the top pole tip.
• the second pole is formed as explained below.
• the Sendust material at corners 234, shown in FIG. 2 are etched away, exposing the reference surface 218, 215, or exposing alignment marks 233 which may have been defined in the previous steps. Subsequent layer masks may be aligned and processed accurately by using these references.
• FIG. 3 is a diagram of magnetic stripes 301 (which may be laminated), separated by glass bonding spacers 305, and stacked on the slider-forming substrate 230, and fused to bond together.
• glass may be deposited on the substrate 230 before stacking stripes 301 and spacers 305. The mating surfaces are lapped/polished to avoid any irregularities.
• FIG. 4 and 5 are diagrams of another embodiment of this invention.
• a slider-forming substrate 299 is shown along with a magnetic substrate 300, e.g., formed of single crystal ferrite.
• Bonding material glass 289 is deposited on the mating surfaces of substrates 299 and 300 and fused at high temperature to bond them together.
• Substrate 299 may itself be magnetic, in which case the substrate 300 is not required.
• Sendust type or high saturation material 340 (forming the bottom pole), the gap material 235 and high saturation or Sendust type material 239 (for forming the top pole tip) are sequentially deposited on the magnetic substrate 300.
• rows 310 are formed by grinding all magnetic material from the spaces 320.
• the width of row 310 may be used to define the track width.
• the width of row 310 may be larger than the desired track width and then the final track width may be defined by photolithography and ion-milling processes in subsequent steps.
• C-cuts 330 are made part-way into the magnetic material 300.
• FIG. 6 shows such an array of C-cut cores, for example.
• the poletip region 290 and the back closure region 291 as defined.
• Coil layers 241 separated by alumina insulation 226 are formed and a magnetic yoke 242 (FIG. 7, 8), e.g., NiFe, is formed to complete the magnetic circuit.
• the track width is defined by photo- patterning and ion milling.
• the C-core 210 may be made of laminated magnetic film bars or magnetic stripes bonded on a slider-forming substrate 299 or by bonding the magnetic substrate 300 and forming magnetic stripes by mechanical means.
• Gap material 235 and a layer of preferably sheet Sendust material 236 are deposited sequentially.
• C- cut 330 may be formed in these stripes, penetrating into the magnetic layer 300.
• the cavity or channel 320, 330 is then filled with low temperature melting glass and planarized (i.e. lapped).
• the mask pattern for poletip region 290, back closure region 291 and the alignment features 283 are formed, and ion-milled into the core 210 to a depth preferably equal to the throat height. This leaves a planar surface 360 except the projected surfaces 308, 307 and the alignment features 283.
• a multi-layer coil 241 separated by alumina insulation 226 may be formed.
• the back-gap closure gap material 227 may be removed in the previous steps.
• insulation 226, preferably a NiFe top yoke 242 is plated in magnetic contact with portions 246 (top of top pole part 239) and 247 (top of back closure part 248).
• FIG. 9 schematically shows the ABS view of such head.
• This fabrication process has several advantages. All the critical processes have been done essentially on a planar surface, unlike the conventional thin film head. For example, track definition by track trimming is done on a planar surface; coil layers 241 are on a planar surface; and the top yoke 242 are on planar surface. If desired, hard-baked photoresist may be used as an insulation material, but alumina type material is preferable.
• pole tips 239 and 307 are made of Sendust which does not recess and smear as much as the NiFe poletips of the thin film heads. All these features together improve the process yield significantly, according to the new head technology disclosed herein.
• Another embodiment of this invention is to make an MR read head on the top of the inductive head discussed above for the write purpose, as is schematically shown in FIG. 10B.
• a simpler approach of this is to form a C-core, preferably of laminated MIG, embedded in the wafer, as has been discussed above.
• an additional thin layer of non-magnetic material photoresist, alumina, nonmagnetic metal, e.g., copper or the like
• write gap 235 and Sendust sheet 236 are deposited, with the help of alignment features 233 (FIG. 2), pattern 239 is formed in the layer 236 and etched to expose the surface 238.
• insulating alumina 226 may be deposited and etched away from the surface at 247, and top at 239. Then the first MR read gap 248, MR film structure with its leads 240, and the second MR read gap 249, are deposited. Gap material is again etched from 246, 247 and coil contact regions 282, 280, 281 (FIG. 7) etc. are exposed. Then NiFe top yoke 242, top MR shield 245, and leads 280, etc. are plated. The rest of the steps to complete the head are performed in a conventional manner.
• FIG. 11 is a schematic of the ABS view of the head schematically shown in FIG. 10B. As is shown, width (TW) of portion 225 defines the write track width. Since in laminated MIG, the thickness TW is controlled very accurately, a very narrow track write head can be made.
• the write head is fabricated first and then the MR read head is formed, thus eliminating the adverse temperature affects on the multilayer, thin, sensitive, MR film structure.
• the head is formed by coupling the same coil layer multiple times with the yoke by folding the yoke multiple times with different segments of the coil.
• FIG. 12 shows C-core 410 separated by spacer 400 and bonded together with the C-core 411.
• FIG. 13 shows folding of the yoke multiple times with the same coil 241.
• Yoke 410 goes under the front segment 250 of the coil 241 ; yoke 442 goes over the back side 251 of the coil 241; yoke 411 goes under the back side 251 of coil 241; and yoke 443 goes over the front 250 of the coil 241.
• the yoke links with the coil twice, thereby increasing the effective number of turns, for improved flux coupling.
• the yoke segments 442, 443 may be made of ferrite material, plated NiFe, or any other soft magnetic material.
• Yoke segment 442 is magnetically coupled to yoke segment 410 and 411 at parts 431 and 430 respectively.
• the yoke segment 443 is coupled to yoke segment 411 at part 432.
• the C-cut cores 410 and 411 are bonded, and the cavities are filled and planarized.
• Gap material 235 and soft magnetic material 236 are deposited.
• the mask pattern for poletip region 290, back closure region 431, 430, 432 and the alignment features 283 are formed, and etched into the core 410 and 411 to a depth, preferably equal to the throat height. This leaves a planar surface 360 except the projecting surfaces 420, 430, 431, 432 and the alignment features 283.
• a multi-layer coil 241 separated by alumina insulation 226 is formed.
• insulation 226, preferably a NiFe top yoke portions 442, 443 are plated in magnetic contact with parts 431, 430, 432.
• FIG. 14A shows magnetic stripes 310 bonded on the slider-making substrate 299. This may be formed by bonding magnetic substrate 300 with the slider-making substrate 299 and machining out portions 320 as has been discussed previously.
• regions 451 are then machined to remove magnetic material.
• magnetic stripes 453 are bonded with the substrate 299 separated by spacer 400 from area 452, shown in FIG. 14C.
• Spacer 400 may be formed by depositing glass on 453 on the surface 401. Stripes 453 are bonded at an elevated level with respect to 452 such that when C-cut 330 are made in magnetic pieces 452, it removes all the magnetic material in regions 457 shown in FIG. 14D.
• channels 454 are cut through magnetic stripes 453, removing magnetic materials therein.
• C-cuts 330 and 461 are made. Since magnetic stripes 453 are bonded at an elevated level, when C-cuts 330 are made, it also removes all magnetic material from regions 457. Then C-cuts 461 are made. Remaining material 459 during making C-cut 461 will not have any adverse effect. This forms the staggered pair of C-cut cores shown in FIG. 12.
• the portion 455 will form a bottom pole-tip.
• the appendix 456 may be removed during the slider fabrication process if so desired.
• Coil 241 may now be deposited around the projecting-out posts 431-432 ⁇ s is shown in FIG. 14E.
• Coil 241 may be mechanically wound instead of depositing in the batch form by photolithography and plating techniques.
• the hand-wound coil has the advantage that the coil resistance is low. After winding the coil, the recessed regions may be filled with hardbaked photoresist, epoxy or alumina type material.
• top yoke parts 442 and 443 are formed to complete the magnetic circuit as per FIG. 14F. This yoke may be bonded ferrite, plated NiFe or any other soft magnetic material.

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• Manufacturing & Machinery (AREA)
• Magnetic Heads (AREA)

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Citations (6)

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• 1994
  • 1994-03-11 JP JP6521117A patent/JPH08508360A/ja active Pending
  • 1994-03-11 CN CN 94191479 patent/CN1119475A/zh active Pending
  • 1994-03-11 WO PCT/US1994/002620 patent/WO1994022136A1/en not_active Application Discontinuation
  • 1994-03-11 EP EP94911547A patent/EP0689707A4/de not_active Withdrawn

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