JP4752756B2 - Thermally assisted magnetic head, head gimbal assembly, hard disk device, and method of manufacturing thermally assisted magnetic head - Google Patents

Description

  The present invention relates to a thermally assisted magnetic head for writing a signal by a thermally assisted magnetic recording system, a head gimbal assembly (HGA) equipped with the thermally assisted magnetic head, a hard disk device equipped with an HGA, and a method of manufacturing a thermally assisted magnetic head. About.

  As the recording density of hard disk drives increases, further improvements in performance of thin film magnetic heads are required. As the thin film magnetic head, a composite thin film magnetic head having a structure in which a magnetic detection element such as a magnetoresistive (MR) effect element and a magnetic recording element such as an electromagnetic coil element are laminated is widely used. Data signals are read from and written to a magnetic disk that is a magnetic recording medium.

  Generally, a magnetic recording medium is a discontinuous body in which magnetic fine particles are aggregated, and each magnetic fine particle has a single magnetic domain structure. Here, one recording bit is composed of a plurality of magnetic fine particles. Therefore, in order to increase the recording density, the magnetic fine particles must be made smaller to reduce the irregularities at the boundaries of the recording bits. However, if the magnetic fine particles are made smaller, a decrease in the thermal stability of magnetization accompanying volume reduction becomes a problem.

A measure of the thermal stability of magnetization is given by K _U V / k _B T. Here, K _U is the magnetic anisotropy energy, V the magnetic microparticle volume of one magnetic particle, k _B the Boltzmann constant, T is the absolute temperature. Making the magnetic fine particles smaller means exactly reducing V, and if it is left as it is, K _U V / k _B T becomes smaller and thermal stability is impaired. As a countermeasure to this problem, it is conceivable to increase the K _U simultaneously, increase in K _U results in an increase in the coercive force of the recording medium. On the other hand, the write magnetic field strength by the magnetic head is almost determined by the saturation magnetic flux density of the soft magnetic material constituting the magnetic pole in the head. Therefore, if the coercive force exceeds an allowable value determined from the limit of the write magnetic field strength, writing becomes impossible.

As a method for solving such a magnetization of the thermal stability problems, while the use of large magnetic material K _U, by applying heat to the recording medium immediately before the write magnetic field is applied, the write to reduce the coercive force A so-called heat-assisted magnetic recording system has been proposed. This method is roughly classified into a magnetic dominant recording method and an optical dominant recording method. In the magnetic dominant recording method, the main subject of writing is an electromagnetic coil element, and the radiation diameter of light is larger than the track width (recording width). On the other hand, in the optical dominant recording method, the main subject of writing is the light emitting portion, and the light emission diameter is substantially the same as the track width (recording width). That is, the magnetic dominant recording method gives the spatial resolution to the magnetic field, whereas the optical dominant recording method gives the spatial resolution to the light.

  As such heat-assisted magnetic head recording devices, Patent Documents 1 to 7 and Non-Patent Document 1 provide a light source such as a semiconductor laser at a position away from a slider provided with a magnetic recording element that generates a magnetic field. A structure in which light from a light source is guided to a medium facing surface of a slider via an optical fiber, a lens, or the like is disclosed.

  Patent Documents 8 to 11 and Non-Patent Document 2 disclose a thermally assisted magnetic head in which a magnetic recording element and a light source are integrated on a side surface of a slider, and a thermally assisted magnetic element in which a magnetic recording element and a light source are integrated on a medium facing surface of the slider. A head is disclosed.

In addition, studies on magnetic heads using SIL (Solid Immersion Lens), which is a high-efficiency condensing element, and plasmon probes, which are near-field light generating elements, have been conducted. Patent Document 12 discloses an apparatus in which a plasmon probe is provided at the tip of a planar waveguide. Further, Patent Document 13 discloses a technique for deflecting transmitted light in accordance with the frequency of AOM by using an acousto-optic element (AOM) in the waveguide. Patent Document 14 discloses a technique for making a solid immersion lens planar in thermally assisted magnetic recording.
International Publication WO92 / 02931 Pamphlet (Japanese Patent Publication No. 6-500194) International Publication WO 98/09284 Pamphlet (Japanese Patent Publication No. 2002-511176) JP-A-10-162444 International Publication No. WO99 / 53482 Pamphlet (Special Table 2002-512725) JP 2000-173093 A JP 2002-298302 A JP 2001-255254 A JP 2001-283404 A JP 2001-325756 A JP 2004-158067 A JP 2004-303299 A US Pat. No. 6,795,630 JP-A-62-218875 JP 2006-202461 A ShintaroMiyanishi et al. “Near-field Assisted Magnetic Recording” IEEE TRANSACTIONS ON MAGNETICS, 2005, Vol. 41, No. 10, p. 2817-2821 Koji Shono and Mitsuga Oshiki “Current Status and Issues of Thermally Assisted Magnetic Recording” Journal of Japan Society of Applied Magnetics, 2005, Vol. 29, No. 1, p. 5-13

  However, the conventional heat-assisted magnetic head requires high positioning accuracy between each element, and even when slight positional deviation occurs, near-field light is not generated and writing is stably stabilized. There is a problem that it is not done. There is also a problem that it is difficult to manufacture a structure that collects light.

  The present invention has been made in view of such problems, and is a thermally assisted magnetic head, a thermally assisted magnetic head, a head gimbal assembly, a hard disk device, and a simple device capable of performing stable and good writing. It is an object of the present invention to provide a method for manufacturing a thermally-assisted magnetic head that can be manufactured in a short time.

In order to solve the above-described problems, a thermally-assisted magnetic head according to the present invention is provided in the thermally-assisted magnetic head, in which a waveguide core having a light incident surface and a light emitting surface facing the magnetic recording medium is provided on the light emitting surface. A plasmon probe, a magnetic recording element located next to the plasmon probe, and a condensing lens embedded in the core, the light condensing position of the condensing lens, and the position of the light emitting surface Is shifted along the optical axis of the core, and the position of the light exit surface coincides with the focal position of the condenser lens .

  According to the thermally-assisted magnetic head according to the present invention, near-field light can be generated by irradiating the plasmon probe with light incident on the core from the light incident surface. Near-field light is emitted from the light exit surface and heats the recording area of the magnetic recording medium. When the magnetic recording medium is heated, the holding power of the recording area decreases, and during the period of decreasing the holding power, the magnetic recording medium is moved so that the recording area is directly below the magnetic recording element located next to the plasmon probe. It is possible to easily write in the recording area by the magnetic field generated by energizing the magnetic recording element.

  Here, the condensing lens is embedded in the core, and the light condensing position of the light by the condensing lens is deviated from the position of the plasmon probe (position of the light emitting surface). In this case, even if the relative position of the light emitting element with respect to the core, in other words, the incident position of light on the light incident surface is slightly shifted, the amount of incident light on the plasmon probe does not change so much and stable near-field light is stable. Can be generated from the plasmon probe, and stable heating and writing can be performed.

Further, the position of the light emitting surface coincides with the focal position of the condenser lens . The focal position of the condensing lens is a condensing position of light when a parallel light beam is input, and this position is uniquely determined regardless of the relative position of the light emitting element to the core. Since divergent light is output from the light-emitting element, if a light exit surface is placed at this position, the divergent light from the light-emitting element is automatically shifted to a position deviated from the focal position without causing a significant decrease in light intensity. It will be focused on.

  Moreover, it is preferable that a condensing lens consists of a convex lens, a binary lens, or a Fresnel lens. Any lens can be embedded in the core and can collect light.

  The condensing lens is a convex lens, and its refractive index is higher than the refractive index of the core. When the optical axis of the core is the Z axis, the thickness direction of the core is the X axis, and the width direction is the Y axis, the convex lens Is composed of a line segment group parallel to the X axis and projecting in the light incident surface direction with respect to the XY plane, and a line segment group parallel to the X axis projecting in the light exit surface direction with respect to the XY plane. It preferably has a light exit curved surface.

  The HGA according to the present invention preferably includes the above-described heat-assisted magnetic head and a suspension that supports the heat-assisted magnetic head. The hard disk device according to the present invention includes the HGA and a magnetic recording medium facing the HGA. It is preferable to provide. In the HGA and hard disk drive equipped with the heat-assisted magnetic head, the heating by the near-field light is stable, so that stable writing is possible.

The manufacturing method of the thermally-assisted magnetic head according to the present invention includes a step of depositing a core on the lower clad, a step of etching a part of the core, and etching to manufacture the above-described thermally-assisted magnetic head. Depositing a material having a refractive index higher than that of the core in the region, forming a condensing lens, forming an upper cladding on the core and the condensing lens, and forming a plasmon The method includes a step of forming a probe and a step of forming a magnetic recording element next to the plasmon probe.

  According to the manufacturing method of the present invention, the condensing lens can be easily formed by the etching and the deposition process of the high refractive index material, so that the heat assist head can be easily manufactured.

  According to the thermally-assisted magnetic head, the thermally-assisted magnetic head, the head gimbal assembly, and the hard disk device according to the present invention, stable and good writing can be performed, and the method for manufacturing the thermally-assisted magnetic head according to the present invention According to this, it can manufacture simply.

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated in detail, referring an accompanying drawing. In the drawings, the same elements are denoted by the same reference numerals. In addition, the dimensional ratios in the components in the drawings and between the components are arbitrary for easy viewing of the drawings.
(Hard disk device)

  FIG. 1 is a perspective view of a hard disk device according to an embodiment.

  The hard disk device 1 includes a magnetic disk 10 that is a plurality of magnetic recording media rotating around a rotation axis of a spindle motor 11, an assembly carriage device 12 for positioning a heat-assisted magnetic head 21 on a track, and the heat-assisted magnetic head. A recording / reproducing and light emission control circuit (control circuit) 13 is provided for controlling the writing and reading operations 21 and controlling a light emitting element which is a light source for generating laser light for heat-assisted magnetic recording, which will be described in detail later. Yes.

  The assembly carriage device 12 is provided with a plurality of drive arms 14. These drive arms 14 can swing around a pivot bearing shaft 16 by a voice coil motor (VCM) 15 and are stacked in a direction along the shaft 16. A head gimbal assembly (HGA) 17 is attached to the tip of each drive arm 14. Each HGA 17 is provided with a heat-assisted magnetic head 21 so as to face the surface of each magnetic disk 10. A surface facing the surface of the magnetic disk 10 is a medium facing surface S (also referred to as an air bearing surface) of the heat-assisted magnetic head 21. The magnetic disk 10, the drive arm 14, the HGA 17, and the heat-assisted magnetic head 21 may be singular. (HGA)

  FIG. 2 is a perspective view of the HGA 17. This figure shows the HGA 17 with the medium facing surface S facing up.

  The HGA 17 is configured by fixing the thermally assisted magnetic head 21 to the tip of the suspension 20 and electrically connecting one end of the wiring member 203 to the terminal electrode of the thermally assisted magnetic head 21. The suspension 20 includes a load beam 200, an elastic flexure 201 fixed and supported on the load beam 200, a tongue portion 204 formed in a leaf spring shape at the tip of the flexure, and a base of the load beam 200. It is mainly configured by a base plate 202 provided and a wiring member 203 which is provided on the flexure 201 and is composed of a lead conductor and connection pads electrically connected to both ends thereof.

It is obvious that the suspension structure in the HGA 17 is not limited to the structure described above. Although not shown, a head driving IC chip may be mounted in the middle of the suspension 20.
(Thermally assisted magnetic head)

  FIG. 3 is an enlarged perspective view of the vicinity of the heat-assisted magnetic head 21 shown in FIG.

  The wiring member 203 is connected to a pair of electrode pads 237 and 237 for recording signals, a pair of electrode pads 238 and 238 for readout signals, and a pair of electrode pads 247 and 248 for driving a light source.

  The thermally assisted magnetic head 21 includes a slider 22, a light source support substrate 230, and a light source unit 23 including a light emitting element (laser diode) 40 serving as a light source for thermally assisted magnetic recording, and a rear surface (first surface) of the slider substrate 220. ) 2201 and the bonding surface (second surface) 2300 of the light source support substrate 230 are in contact with each other and bonded and fixed. Here, the back surface 2201 of the slider substrate 220 is a surface opposite to the medium facing surface S of the slider 22. In addition, the bottom surface 2301 of the light source support substrate 230 is bonded to the tongue portion 204 of the flexure 201 with, for example, an adhesive such as an epoxy resin.

  The slider 22 includes a slider substrate 220 and a magnetic head unit 32 for writing and reading data signals.

The slider substrate 220 has a plate-like shape and has a medium facing surface S processed so as to obtain an appropriate flying height. The slider substrate 220 is made of conductive Altic (Al ₂ O ₃ —TiC) or the like.

  The magnetic head portion 32 is formed on the integration surface 2202 that is a side surface substantially perpendicular to the medium facing surface S of the slider substrate 220. The magnetic head unit 32 includes an MR effect element 33 as a magnetic detection element for detecting magnetic information, an electromagnetic coil element 34 as a perpendicular (or in-plane) magnetic recording element for writing magnetic information by generating a magnetic field, and an MR effect element 33. And a core 35 of a waveguide as a planar waveguide provided between the electromagnetic coil element 34 and a plasmon probe (near-field light generator) for generating near-field light for heating the recording layer portion of the magnetic disk 36, and an insulating layer (clad) 38 formed on the integrated surface 2202 so as to cover the MR effect element 33, the electromagnetic coil element 34, the core 35, and the plasmon probe 36.

  Further, the magnetic head portion 32 is formed on the exposed surface of the insulating layer 38 and is connected to the input / output terminals of the MR effect element 33 and connected to both ends of the pair of signal terminals 371 and 371 and the electromagnetic coil element 34. Are provided with a pair of signal terminal electrode pads 373 and 373 and a ground electrode pad 375 electrically connected to the slider substrate 220. The electrode pad 375 electrically connected to the slider substrate 220 through the via hole 375a is connected to the electrode pad 247 of the flexure 201 by a bonding wire. The potential of the slider substrate 220 is, for example, grounded by the electrode pad 247. Controlled to potential.

  The end surfaces of the MR effect element 33, the electromagnetic coil element 34, and the plasmon probe 36 are exposed on the medium facing surface S. Further, both ends of the light emitting element 40 are connected to electrode pads 47 and 48, respectively.

  4 is a cross-sectional view of the thermally assisted magnetic head 21 shown in FIG.

  The MR effect element 33 includes an MR multilayer 332 and a lower shield layer 330 and an upper shield layer 334 disposed at positions sandwiching the MR multilayer 332. The lower shield layer 330 and the upper shield layer 334 are made of a magnetic material such as NiFe, CoFeNi, CoFe, FeN, or FeZrN having a thickness of about 0.5 to 3 μm formed by a pattern plating method including a frame plating method, for example. can do. The upper and lower shield layers 334 and 330 prevent the MR multilayer 332 from being affected by an external magnetic field that causes noise.

  The MR multilayer 332 is composed of a current-in-plane (CIP (Current In Plane)) giant magnetoresistance (GMR) multilayer film, a vertical conduction type (CPP (Current Perpendicular to Plane)) GMR multilayer film, or a tunnel magnetism. A magnetoresistive effect film such as a resistance (TMR (Tunnel Magneto Resistance)) multilayer film is included, and a signal magnetic field from a magnetic disk is sensed with very high sensitivity.

  When the MR multilayer 332 includes, for example, a TMR effect multilayer film, the antiferromagnetic layer having a thickness of about 5 to 15 nm made of IrMn, PtMn, NiMn, RuRhMn, and the like, and CoFe that is a ferromagnetic material, for example, or Ru A magnetization pinned layer composed of two layers of CoFe or the like with a nonmagnetic metal layer or the like sandwiched therebetween and the magnetization direction of which is pinned by an antiferromagnetic layer, and a thickness of 0.5 to 1 nm made of, for example, Al or AlCu A tunnel barrier layer made of a non-magnetic dielectric material in which a metal film of a degree is oxidized by oxygen introduced into the vacuum apparatus or by natural oxidation, and a CoFe having a thickness of about 1 nm, for example, a ferromagnetic material, A magnetization free layer that is composed of a two-layer film of about 4 nm of NiFe or the like and that forms a tunnel exchange coupling with the magnetization fixed layer via the tunnel barrier layer is sequentially laminated. Have a structure.

  An inter-element shield layer 148 made of the same material as the lower shield layer 330 is formed between the MR effect element 33 and the core 35. The inter-element shield layer 148 plays a role of blocking the MR effect element 33 from the magnetic field generated by the electromagnetic coil element 34 and preventing external noise during reading. Further, a backing coil portion may be further formed between the inter-element shield layer 148 and the core 35. The backing coil section generates a magnetic flux that is generated from the electromagnetic coil element 34 and cancels the magnetic flux loop passing through the upper and lower electrode layers of the MR effect element 33, and is a wide adjacent track that is an unnecessary write or erase operation on the magnetic disk. This is intended to suppress the erasing (WAIT) phenomenon.

  Between the shield layer 330 334 opposite to the medium facing surface S of the MR stack 332, between the shield layer 330 334 148 opposite to the medium facing surface S, between the lower shield layer 330 and the slider substrate 220, An insulating layer 38 made of alumina or the like is formed between the inter-element shield layer 148 and the core 35.

  When the MR multilayer 332 includes a CIP-GMR multilayer film, an insulating upper and lower shield made of alumina or the like is formed between each of the upper and lower shield layers 334 and 330 and the MR multilayer 332. Each gap layer is provided. Further, although not shown, an MR lead conductor layer for supplying a sense current to the MR multilayer 332 and taking out a reproduction output is formed. On the other hand, when the MR multilayer 332 includes a CPP-GMR multilayer film or a TMR multilayer film, the upper and lower shield layers 334 and 330 also function as upper and lower electrode layers, respectively. In this case, the upper and lower shield gap layers and the MR lead conductor layer are unnecessary and are omitted.

  Hard bias layers HM (see FIG. 7) made of a ferromagnetic material such as CoTa, CoCrPt, and CoPt for applying a longitudinal bias magnetic field for stabilizing the magnetic domain are provided on both sides of the MR multilayer 332 in the track width direction. It is formed.

  The electromagnetic coil element 34 is preferably for perpendicular magnetic recording, and includes a main magnetic pole layer 340, a gap layer 341a, a coil insulating layer 341b, a coil layer 342, and an auxiliary magnetic pole layer 344, as shown in FIG.

  The main magnetic pole layer 340 is a magnetic path for guiding the magnetic flux induced by the coil layer 342 while converging it to the recording layer of the magnetic disk (medium) on which writing is performed. Here, the width in the track width direction (the depth direction in the drawing in FIG. 4) and the thickness in the stacking direction (the left-right direction in FIG. 4) of the end of the main magnetic pole layer 340 on the medium facing surface S side are compared with those in other portions. It is preferable to make it small. As a result, it is possible to generate a fine and strong write magnetic field corresponding to high recording density.

  The end portion on the medium facing surface S side of the auxiliary magnetic pole layer 344 magnetically coupled to the main magnetic pole layer 340 forms a trailing shield part having a wider layer cross section than the other part of the auxiliary magnetic pole layer 344. The auxiliary magnetic pole layer 344 faces the end of the main magnetic pole layer 340 on the medium facing surface S side via a gap layer (cladding) 341a and a coil insulating layer 341b formed of an insulating material such as alumina. By providing such an auxiliary magnetic pole layer 344, the magnetic field gradient between the auxiliary magnetic pole layer 344 and the main magnetic pole layer 340 in the vicinity of the medium facing surface S becomes steeper. As a result, the jitter of the signal output is reduced, and the error rate at the time of reading can be reduced.

  The auxiliary magnetic pole layer 344 is, for example, an alloy made of any two or three of Ni, Fe, and Co formed by using, for example, a frame plating method, a sputtering method or the like with a thickness of about 0.5 to about 5 μm. Or an alloy containing these as a main component and a predetermined element added thereto.

The gap layer 341a separates the coil layer 342 and the main magnetic pole layer 340. For example, Al ₂ having a thickness of about 0.01 to about 0.5 μm and formed using, for example, a sputtering method, a CVD method, or the like. and a O ₃ or DLC or the like.

  The coil layer 342 is made of, for example, Cu having a thickness of about 0.5 to about 3 μm and formed by using, for example, a frame plating method. The rear end of the main magnetic pole layer 340 and the portion of the auxiliary magnetic pole layer 344 away from the medium facing surface S are coupled, and the coil layer 342 is formed so as to surround the coupled portion.

  The coil insulating layer 341b separates the coil layer 342 and the auxiliary magnetic pole layer 344, and is made of, for example, an electrically insulating material such as thermoset alumina or a resist layer having a thickness of about 0.1 to about 5 μm. .

  FIG. 5 is a circuit diagram of the heat-assisted magnetic head 21.

  One of the wirings constituting the wiring member 203 is electrically connected to the cathode of the light emitting element 40 via the electrode pad 247 and the electrode pad 47, and another wiring is connected via the electrode pad 248 and the electrode pad 48. The anode of the light emitting element 40 is electrically connected. When a drive current is supplied between the electrode pads 247 and 248, the light emitting element 40 emits light. This light is applied to the recording region R of the magnetic recording medium through the core of the planar waveguide and the medium facing surface S (see FIG. 4).

  Another pair of wires constituting the wiring member 203 is connected to both ends of the electromagnetic coil element 34 via the electrode pad 237, the bonding wire BW, and the electrode pad 371, respectively. When a voltage is applied between the pair of electrode pads 237, the electromagnetic coil element 34 as a magnetic recording element is energized and a writing magnetic field is generated. In the thermally assisted magnetic head 21, the light emitted from the light emitting element 40 is incident on the light incident surface 354 of the core 35 of the planar waveguide, is emitted from the light emitting surface provided on the medium facing surface S, and is subjected to magnetic recording. The recording area R of the medium is irradiated (see FIG. 4). Therefore, the temperature of the recording area R of the magnetic recording medium facing the medium facing surface rises, and the holding force of the recording area R temporarily decreases. Information can be written in the recording area R by energizing the electromagnetic coil element 34 and generating a write magnetic field within the holding power decrease period.

  Another pair of wirings constituting the wiring member 203 is connected to both ends of the MR effect element 33 via the electrode pad 238, the bonding wire BW, and the electrode pad 373, respectively. When a voltage is applied to the pair of electrode pads 238, a sense current flows through the MR effect element 33. Information written in the recording region R can be read by passing a sense current through the MR effect element 33.

  FIG. 6 is a plan view of the main part of the magnetic head viewed from the medium facing surface side.

  The tip of the main magnetic pole layer 340 on the medium facing surface S side is tapered so that the length of the side on the leading side, that is, the side of the slider substrate 220 becomes an inverted trapezoid shorter than the length of the side on the trailing side. .

  The end face of the main magnetic pole layer 340 on the medium facing surface side is provided with a bevel angle θ so that unnecessary writing or the like is not exerted on an adjacent track due to the influence of a skew angle generated by driving with a rotary actuator. The magnitude of the bevel angle θ is, for example, about 15 °. Actually, the write magnetic field is mainly generated in the vicinity of the long side on the trailing side. In the case of a magnetic dominant, the width of the write track is determined by the length of the long side.

  Here, the main magnetic pole layer 340 has, for example, a total thickness of about 0.01 to about 0.5 μm at the end on the medium facing surface S side, and a total thickness of other than this end is about 0.5. About 3.0 μm, for example, an alloy composed of any two or three of Ni, Fe and Co formed by using frame plating method, sputtering method or the like, or a predetermined element containing these as main components is added. It is preferable that it is comprised from the alloy etc. which were made. The track width can be set to 100 nm, for example.

  FIG. 7 is a perspective view of the main part of the heat-assisted magnetic head 21.

  When the thickness direction of the core 35 is the X axis, the width direction is the Y axis, and the longitudinal direction is the Z axis, the light emitted from the light emitting surface of the light emitting element 40 along the Z axis enters the light incident surface 354.

  The core 35 is located between the MR effect element 33 and the electromagnetic coil element 34, extends in parallel with the integration surface (YZ plane) 2202 (see FIG. 4), and the medium body facing surface S of the magnetic head unit 32. To the surface 32a opposite to the medium facing surface S of the magnetic head portion 32, and in this example is an elliptical plate. The core 35 extends in the Z direction from the medium facing surface S, and forms two side surfaces 351a and 351b facing each other in the track width direction, two upper surfaces 352a and 352b parallel to the accumulation surface 2202, and the medium facing surface S. The light emitting surface 353 and the light incident surface 354 opposite to the light emitting surface 353 are provided. The upper surface 352a, the lower surface 352b, and the two side surfaces 351a and 351b of the core 35 are in contact with the insulating layer 38 that has a refractive index smaller than that of the core 35 and functions as a cladding for the core 35.

  The core 35 guides the light incident from the light incident surface 354 to the light emitting surface 353 which is the end surface on the medium facing surface S side while reflecting the light from both side surfaces 351a and 351b and the upper surface 352a and the lower surface 352b. It is possible. The maximum width W35 of the core 35 in the track width direction can be, for example, 1 to 200 μm, the thickness T35 can be, for example, 2 to 10 μm, and the height H35 can be 10 to 300 μm.

The core 35 is made of a dielectric material having a refractive index n higher than that of the material forming the insulating layer 38, for example, using a sputtering method or the like in any part. For example, when the insulating layer 38 as a clad is formed from SiO ₂ (n = 1.5), the core 35 may be formed from Al ₂ O ₃ (n = 1.63). Further, when the insulating layer 38 is made of Al ₂ O ₃ (n = 1.63), the core 35 is composed of Ta ₂ O ₅ (n = 2.16), Nb ₂ O ₅ (n = 2.2. 33), TiO (n = 2.3 to 2.55), or TiO ₂ (n = 2.3 to 2.55). By configuring the core 35 with such a material, not only the good optical characteristics of the material itself but also the total reflection conditions at the interface are adjusted, so that the propagation loss of the laser light is reduced, and the near-field light is reduced. The generation efficiency is improved.

  The plasmon probe 36 is a plate-like member disposed almost at the center of the light emitting surface 353 of the core 35 of the waveguide. The plasmon probe 36 is embedded in the light emitting surface 353 of the core 35 so that its end surface is exposed to the medium facing surface S.

  Although the magnetic recording medium is also heated by direct irradiation with light from the light emitting element, the heat-assisted magnetic head 21 of the present invention includes a plasmon probe 36 provided on the light emitting surface 353 of the core 35. . In this case, near-field light is generated by irradiating the plasmon probe 36 with light from the light emitting element 40. When the plasmon probe 36 is irradiated with light, electrons in the metal constituting the plasmon probe 36 vibrate in plasma, and an electric field is concentrated at the tip. Since the spread of the near-field light is about the radius of the tip of the plasmon probe, if the radius of the tip is set to be equal to or less than the track width, there is an effect that the emitted light is artificially narrowed to the diffraction limit or less. .

  Further, a part of the incident light from the light emitting element 40 leaks outside the light incident surface 354 of the core 36, but it is not preferable that this leaked light functions as stray light. Therefore, the thermally-assisted magnetic head 21 includes a clad (insulating layer 38, gap layer 341a) provided around the core 35 and a metal in contact with the clad. That is, if a metal is brought into contact with the clad, leaked light is absorbed by the metal. As this metal, a metal layer ME such as Cu directly in contact with the insulating layer 38 (see FIG. 4), or a metal coil layer (spiral coil) 342 in contact with the insulating layer 38 or the gap layer 341a can be used. . The coil layer 342 also serves to generate a write magnetic field. The clad is provided around the core 35 and confines light incident in the core.

  The main magnetic pole layer 340 extends from the spiral center of the coil layer 342 toward the medium facing surface S. When the coil layer 342 is energized, a magnetic field is guided to the medium facing surface S through the main magnetic pole layer 340, and a writing magnetic field spreading outward from the medium facing surface S can be generated. Since the layer 342 is made of metal and is in contact with the clad, leakage light can also be absorbed. Further, a light shielding film may be provided around the light incident surface 354.

  The light incident surface 354 is preferably inclined with respect to the XY plane (the light emitting surface of the light emitting element 40). In this case, the light reflected by the light incident surface 354 is directed to the light emitting element 40 side. Since it does not return, the life of the light emitting element 40 can be extended.

  The above-described heat-assisted magnetic head 21 has a slider substrate 220 having a medium facing surface S, a first surface 2201 located on the opposite side of the medium facing surface S, and a side surface located between the medium facing surface and the first surface 2201. A planar waveguide core 35 having a light exit surface 353 on the medium facing surface S side, and a magnetic recording element 34 close to the light exit surface 353, and fixed to one of the side surfaces of the slider substrate 220. A magnetic head unit 32, a light source support substrate 230 having a second surface 2300 fixed to the first surface 2201, and a light emitting element 40 facing the light incident surface 354 of the core 35 and fixed to the light source support substrate 230. (See FIG. 4). Note that the proximity means a distance at which the recording area of the magnetic recording medium heated by the light emitting surface 353 can apply a magnetic field from the magnetic recording element 34 to the recording area before returning to the original temperature. Further, the thickness of the core 35 in the X-axis direction is constant, and the XY cross section is a quadrangle.

  Since the light emitting element 40 is fixed to the light source support substrate 230 and the first surface 2201 of the slider substrate 220 is fixed to the second surface 2300 of the light source support substrate 230, the position of the slider substrate 220 and the light emitting element 40. The relationship is fixed. Since the light emitting element 40 faces the light incident surface 354 of the core, long-distance light propagation is not performed as in the prior art, and mounting errors and light coupling loss are allowed, and the emitted light of the light emitting element is opposed to the medium. Can lead to the surface.

Further, the spot diameter or half-value width of the light intensity distribution along the X axis in the XY plane including the incident light barycentric position G on the light incident surface 354 is set to be larger than the thickness T35 of the core 35.
Here, a condensing lens 35L having a constant thickness is embedded in the core 35 of the waveguide. This heat-assisted magnetic head includes a magnetic recording element 34 located next to the plasmon probe 36 provided on the light emitting surface 353. The condensing lens 35L condenses light incident on the plasmon probe 36 from the light emitting element 40 into the core 35.

  FIG. 8 is an explanatory diagram showing a plan view of the core 35 and the type of the condenser lens 35L.

  The center of gravity of the condensing lens 35L is located at a distance Z1 from the light incident surface 354 in the core 35, and is located at a distance Z2 from the light emitting surface 353 (see FIG. 8A). The distance Z1 is smaller than the distance Z2, and it is possible to irradiate the plasmon probe 36 with light focused to a certain intensity even with a condensing lens having a relatively large radius of curvature.

  Various shapes can be considered for the condensing lens 35L.

Figure 8 (b) is a condenser lens 35L constituting a single convex lens 35L _1.

Figure 8 (c) is a condenser lens 35L having a pair of convex lenses _35L 1, 35L group of lenses is interposed concave lens 35L ₃ during _2.

FIG. 8D is a binary diagram in which a plurality of rectangular parallelepipeds 35L ₁₁ , 35L ₁₂ , 35L ₁₃ , 35L ₁₄ , 35L ₁₅ , 35L ₁₆ , 35L ₁₇ , and 35L ₁₈ having different Y-direction lengths are arranged along the Y axis. These are lenses, and their refractive index is higher than the refractive index of the material of the surrounding core 35. The lengths in the Y direction of the high refractive index rectangular parallelepipeds 35L ₁₁ , 35L ₁₂ , 35L ₁₃ , 35L ₁₄ , 35L ₁₅ , 35L ₁₆ , 35L ₁₇ , and 35L ₁₈ become shorter as the distance from the center of gravity of the whole becomes shorter, and the separation interval also becomes narrower. Yes.

FIG. 8E shows a plurality of step-like transparent bodies 35L ₂₁ , 35L ₂₂ , 35L ₂₃ , 35L ₂₄ , 35L ₂₅ , 35L ₂₆ , 35L ₂₇ , and 35L ₂₈ with different Y-direction lengths separated along the Y axis. These are binary lenses arranged side by side, and their refractive index is higher than the refractive index of the material of the surrounding core 35. The stepped shape means that each transparent body has two planes parallel to the XY plane on the light emitting surface 353 side, and a step is formed between these two planes. Each transparent body has one plane parallel to the XY plane on the light incident surface 354 side. The stepwise transparent bodies 35L ₂₁ , 35L ₂₂ , 35L ₂₃ , 35L ₂₄ , 35L ₂₅ , 35L ₂₆ , 35L ₂₇ , and 35L ₂₈ having a high refractive index have shorter Y-direction lengths as they are farther from the center of gravity of the whole. Is also narrower.

Fig. 8 (f) a condenser lens 35L consisting of Fresnel lens _{35L 30,} YZ cross section of the Fresnel lens _{35L 30} has the shape of a sawtooth.

Thus, it is preferable that the condensing lens 35L consists of a convex lens, a binary lens, or a Fresnel lens, and any lens can be embedded in the core 35 and can condense. In any of the condensing lenses 35L, the light condensing position P (position of the distance f _LD from the condensing lens center) and the position of the light emitting surface 353 (focal position Q) are the same. , _Shifted along the optical axis Z _AX of the core 35.

  FIG. 9 is a perspective view of the core 35 when a convex lens is used as an example of the condenser lens 35L.

  Laser light emitted from the end face of the light emitting element (laser diode) 40 with a directivity angle enters the core 35 through the light incident surface 354. This light is collected by the condenser lens 35L, and is collected at a position farther from the emission surface 353 of the core 35, that is, at a position P outside the core 35. A plasmon probe 36 is disposed between the condensing lens 35L and the condensing position P. By irradiating the plasmon probe 36 with light from the condenser lens 35L, near-field light can be generated from the plasmon probe 36.

  Near-field light is emitted from the light emission surface 353 and heats the recording region R of the magnetic recording medium MRM. When the recording area R of the magnetic recording medium MRM is heated, the holding force of the recording area R is reduced, and the recording area R of the plasmon probe 36 is moved by moving the magnetic recording medium MRM during the period in which the holding force R is reduced. The recording area R can be easily written by the magnetic field generated by energizing the magnetic recording element 34 by moving the magnetic recording element 34 directly below the adjacent magnetic recording element 34.

Here, the condensing lens 35L is embedded in the core 35, and the condensing position of light by the condensing lens 35L (position at a distance f _LD from the condensing lens center) P is the position of the plasmon probe 36 (collection). The distance f _LENS from the center of the optical lens: the position of the light exit surface 353) is deviated from Q.

It is assumed that the position where the light emitting element 40 exists is shifted from the optical axis Z _AX of the core 35 along the Y axis. The principal ray from the light emitting element 40 ′ when displaced is passed through the focal position Q of the condenser lens 35L, but the light condensing position of the light from the light emitting element 40 ′ is shifted from the position P along the Y-axis direction. It will be.

  However, since the light condensing position P of the light by the condensing lens 35L is shifted from the lens focal position Q along the Z axis, the relative position of the light emitting element 40 with respect to the core 35, in other words, the light incident surface 354. Even when the incident position of the light slightly deviates, the amount of light incident on the plasmon probe 36 does not change much, and stable near-field light can be generated from the plasmon probe 36 to perform stable heating and writing. .

  Further, in this example, the position of the light emitting surface 353 coincides with the focal position Q of the condenser lens 35L. The focal position Q of the condensing lens 35L is a light condensing position when a parallel light beam is input, and this position is uniquely determined regardless of the relative position of the light emitting element 40 to the core 35. Since divergent light is output from the light emitting element 40, if the light emitting surface 353 is disposed at this position Q, the divergent light from the light emitting element 40 is shifted from the focal position Q without causing a significant decrease in light intensity. The light is automatically condensed at the position P. In addition, even when the light emitting element 40 is displaced along the Y-axis direction, the principal ray passes through the focal position Q, so that there is an advantage that the plasmon probe 36 can be irradiated with light.

The condensing lens 35L of this example is a convex lens, and its refractive index is higher than the refractive index of the core 35. The optical axis (Z _AX ) of the core 35 is the Z axis, and the thickness direction of the core 35 is the X axis. , and the width direction and Y-axis, the convex lens 35L includes a light incident curved surface 35X _a protruding to the light incident surface 354 direction with respect to the XY plane made from a group of parallel line segments X _a to X axis, parallel to the X axis and a light emitting curved surface 35X _B projecting the light emitting surface 353 direction with respect to the XY plane made from a group of such line X _B.

Since the light emitted from the light emitting element 40 has directivity, it tends to spread as it progresses in the −Z-axis direction, but bends inward after passing through the light incident curved surface 35X _A , Moreover, further condenses at a predetermined focusing position P bent inwardly when passing through the light exit curved 35X _B.

  FIG. 10 is a perspective view of the plasmon probe 36 viewed from the medium facing surface S. FIG.

  The plasmon probe 36 has a triangular shape when viewed from the medium facing surface S, and is formed of a conductive material. A triangular base 36d is arranged parallel to the integration surface 2202 of the slider substrate 220, that is, parallel to the track width direction, and a vertex 36c facing the base is arranged closer to the main magnetic pole layer 340 of the electromagnetic coil element 34 than the base 36d. Specifically, the apex 36 c is disposed so as to face the leading edge E of the main magnetic pole layer 340. A preferred form of the plasmon probe 36 is an isosceles triangle in which the two base angles at both ends of the base 36d are the same.

  The radius of curvature r of the apex 36c of the plasmon probe 36 is preferably 5 to 100 nm. The height H36 of the triangle is preferably smaller than the wavelength of the incident laser beam and is preferably 20 to 400 nm. The width W of the base 36d is preferably sufficiently smaller than the wavelength of the incident laser light and is preferably 20 to 400 nm. The angle β of the vertex 36c is 60 degrees, for example.

  The thickness T36 of the plasmon probe 36 is preferably 10 to 100 nm.

  When such a near-field light emitting unit 36 is provided on the light emitting surface 353 of the core 35, the electric field is concentrated in the vicinity of the vertex 36c of the near-field light emitting unit 36, and the near field from the vicinity of the vertex 36c toward the medium. Light is generated.

  The near-field light generally has the strongest intensity at the boundary of the plasmon probe 36 when viewed from the medium facing surface S, depending on the wavelength of the incident laser light and the shape of the core 35. In particular, in the present embodiment, the electric field vector of light reaching the plasmon probe 36 is in the stacking direction (X direction) of the light emitting elements 40. Therefore, the strongest near-field light is emitted in the vicinity of the vertex 36c. That is, in the heat assisting action of heating the recording layer part of the magnetic disk with light, the part facing the vicinity of the apex 36c becomes the main heating action part.

  The electric field strength of this near-field light is orders of magnitude stronger than that of incident light, and this very strong near-field light rapidly heats the opposing local portion of the magnetic disk surface. As a result, the coercive force of this local portion is reduced to a size that allows writing by a write magnetic field, so that even if a high coercivity magnetic disk for high-density recording is used, writing by the electromagnetic coil element 34 is possible. Become. The near-field light reaches a depth of about 10 to 30 nm from the medium facing surface S toward the surface of the magnetic disk. Accordingly, in the present situation where the flying height is 10 nm or less, the near-field light can sufficiently reach the recording layer portion. Further, the width of the near-field light generated in this way in the track width direction and the width in the medium movement direction is approximately the same as the above-mentioned depth of arrival of the near-field light, and the electric field intensity of the near-field light is Since it decays exponentially as the distance increases, the recording layer portion of the magnetic disk can be heated very locally.

  FIG. 11 is a graph showing the relationship between the wavelength λ (nm) of the light incident on the plasmon probe 36 and the near-field light intensity I (au). Note that the length of the plasmon probe 36 is H36 = 100 nm.

  When Al is used as the plasmon probe 36, the wavelength λ (nm) of incident light has an intensity peak of near-field light near 350 nm, and when Ag is used, it has an intensity peak near 530 nm, When Au is used, it has an intensity peak near 650 nm. As a material for the plasmon probe 36, Cu, Pd, Pt, Rh, or Ir can be used in addition to Al, Ag, and Au. Further, as a material of the plasmon probe 36, an alloy made of some combination of these metal materials can be adopted.

FIG. 12 is a graph showing the relationship between the wavelength λ (nm) of the light incident on the plasmon probe 36 and the near-field light intensity I (au). The material of the plasmon probe 36 is Au, and the length H36 is 100 nm, 200 nm, and 300 nm. The length H36 is preferably 20 to 400 nm. However, when the light having a short wavelength is incident, the half-value width of the spectrum tends to be narrowed, and resistance to fluctuations in the near-field light intensity against fluctuations in the incident light wavelength is increased.
(Light source unit)

  Next, the components of the light source unit 23 of the thermally-assisted magnetic head 21 will be described with reference to FIGS. 3 and 4 again.

  The light source unit 23 mainly includes a light source support substrate 230 and a light emitting element 40 whose outer shape is a plate shape.

The light source support substrate 230 is a substrate made of AlTiC (Al ₂ O ₃ —TiC) or the like, and has a bonding surface 2300 bonded to the back surface 2201 of the slider substrate 220. A heat insulating layer 230 a such as alumina is formed on the bonding surface 2300. An insulating layer 41 made of an insulating material such as alumina is provided on an element forming surface 2302 which is one side surface when the adhesive surface 2300 is a bottom surface. An electrode pad is formed on the insulating layer 41. 47 and 48 are formed, and the light emitting element 40 is fixed on the electrode pad 47.

  The electrode pads 47 and 48 are formed for laser driving on the surface 411 intersecting the surface of the insulating layer 41 and the medium facing surface S, in other words, the surface 411 parallel to the integration surface 2202 of the slider substrate 220.

  As shown in FIG. 4, the electrode pad 47 is electrically connected to the light source support substrate 230 through a via hole 47 a provided in the insulating layer 41. The electrode pad 47 also functions as a heat sink for releasing heat when driving the light emitting element 40 to the light source support substrate 230 side through the via hole 47a.

  As shown in FIG. 3, the electrode pad 47 is formed at the center of the surface 411 of the insulating layer 41 so as to extend in the track width direction. On the other hand, the electrode pad 48 is formed at a position separated from the electrode pad 47 in the track width direction. The electrode pads 47 and 48 further extend toward the flexure 201 side for connection to the flexure 201 by solder reflow.

  The electrode pads 47 and 48 are electrically connected to the electrode pads 247 and 248 of the flexure 201 by reflow soldering, respectively, so that the light source can be driven. Further, since the electrode pad 47 is electrically connected to the light source support substrate 230 as described above, the potential of the light source support substrate 230 can be controlled to, for example, the ground potential by the electrode pad 247.

  The electrode pads 47 and 48 are metal layers formed through a base layer made of Ta, Ti or the like having a thickness of about 10 nm, for example, and having a thickness of about 1 to 3 μm, such as a vacuum deposition method or a sputtering method. It can be formed from a layer of Au, Cu or the like formed using

  The light emitting element 40 is electrically connected to the electrode pad 47 by a solder layer 42 (see FIG. 4) made of a conductive solder material such as Au—Sn. At this time, the light emitting element 40 is disposed with respect to the electrode pad 47 so as to cover only a part of the electrode pad 47.

  FIG. 13 is a perspective view of the light emitting element 40.

The light emitting element (laser diode) 40 may have the same structure as that usually used for optical disk storage, for example, an n electrode 40a, an n-GaAs substrate 40b, and an n-InGaAlP cladding layer 40c. When a first InGaAlP guide layer 40d, an active layer 40e made of a multiple quantum well (InGaP / InGaAlP) or the like, a second InGaAlP guide layer 40f, and the p-InGaAlP cladding layer 40 ^g, * n-GaAs current blocking The layer 40h, the p-GaAs contact layer 40i, and the p-electrode 40j are sequentially stacked. Reflective films 50 and 51 made of SiO ₂ , Al ₂ O ₃ or the like for exciting oscillation due to total reflection are formed before and after the cleavage planes of these multilayer structures, and the emitted light from which laser light is emitted At the end 400, an opening is provided at the position of the active layer 40e in one reflective film 50. The light emitting element 40 emits laser light from the light emitting end 400 when a voltage is applied in the film thickness direction.

The wavelength λ _L of the emitted laser light is, for example, about 600 to 650 nm. However, it should be noted that there is an appropriate excitation wavelength depending on the metal material of the plasmon probe 36. For example, when Au is used as the plasmon probe 36, the wavelength λ _{L of the} laser light is preferably near 600 nm.

  As described above, the light emitting element 40 has a width (W40) of about 200 to 350 μm, a length (depth, L40) of 250 to 600 μm, and a thickness (T40) of about 60 to 200 μm, as described above. Here, the width W40 of the light emitting element 40 can be reduced to, for example, about 100 μm, with the interval between the opposing ends of the current blocking layer 40h as a lower limit. However, the length of the light emitting element 40 is an amount related to the current density and cannot be reduced so much. In any case, it is preferable that the light emitting element 40 has a considerable size in consideration of handling during mounting.

  In driving the light emitting element 40, the power source in the hard disk device can be used. Actually, the hard disk device usually has a power supply of about 2 V, for example, and has a sufficient voltage for the laser oscillation operation. The power consumption of the light emitting element 40 is, for example, about several tens of mW, and can be sufficiently covered by the power source in the hard disk device.

  The n-electrode 40a of the light-emitting element 40 is fixed to the electrode pad 47 by a solder layer 42 (see FIG. 4) such as AuSn. Here, the light emitting element 40 is fixed to the light source support substrate 230 so that the light emitting end (light emitting surface) 400 of the light emitting element 40 is downward (−Z direction) in FIG. 4, that is, the light emitting end 400 is parallel to the adhesive surface 2300. Thus, the light exit end 400 can face the light incident surface 354 of the core 35 of the slider 22. In actual fixing of the light emitting element 40, for example, an AuSn alloy vapor deposition film having a thickness of about 0.7 to 1 μm is formed on the surface of the electrode pad 47, and after placing the light emitting element 40, it is hot under a hot air blower. What is necessary is just to fix by heating to about 200-300 degreeC by a plate etc.

  Further, the electrode pad 48 and the p-electrode 40j of the light emitting element 40 are electrically connected by a bonding wire. The electrode connected to the electrode pad 47 may not be the n electrode 40a but the p electrode 40j. In this case, the n electrode 40a is connected to the electrode pad 48 by a bonding wire. Furthermore, an electrical connection structure that does not use a bonding wire is also possible by processing the support substrate side of the light emitting element 40 into a stepped shape.

  Here, when soldering with the above-described AuSn alloy, the light source unit is heated to a high temperature of about 300 ° C., for example. According to the present invention, the light source unit 23 is manufactured separately from the slider 22. Therefore, the magnetic head portion in the slider is not affected by the high temperature.

  The back surface 2201 of the slider 22 and the adhesive surface 2300 of the light source unit 23 are adhered to each other by an adhesive layer 44 (see FIG. 4) such as a UV curable adhesive, for example. 400 is arranged to face the light incident surface 354 of the core 35.

Of course, the configurations of the light emitting element 40 and the electrode pad are not limited to the above-described embodiments. For example, the light emitting element 40 has other configurations using other semiconductor materials such as GaAlAs. It may be. Further, it is possible to use other brazing material for soldering the light emitting element 40 and the electrode. Furthermore, the light emitting element 40 may be formed by epitaxially growing a semiconductor material directly on the unit substrate.
(Production method)

  Next, a method for manufacturing the above-described heat-assisted magnetic head will be briefly described.

  First, the slider 22 is manufactured. Specifically, the slider substrate 220 is prepared, the MR effect element 33 and the inter-element shield layer 148 are formed using a known method, and the insulating layer 38 such as alumina is further formed as a base.

  Subsequently, a waveguide and plasmon probe 36 is formed. This process will be described in detail with reference to FIGS.

  14 and 15 are perspective views for explaining an embodiment of a method for forming the waveguide and the plasmon probe 36. FIG.

First, as shown in FIG. 14A, first, Ta ₂ O ₅ or the like having a higher refractive index than the insulating layer 38a, which is a part of the core 35, is formed on the insulating layer 38a such as Al ₂ O _3. A dielectric layer 35a is formed, a metal layer 36a of Au or the like is formed thereon, and a resist pattern 1002 having a recessed bottom for lift-off is formed thereon.

  Next, as shown in FIG. 14B, an unnecessary portion of the metal layer 36a is removed by using an ion milling method or the like except for the portion immediately below the resist pattern 1002, thereby forming a lower portion on the dielectric film 35a. A pattern in which a wide trapezoidal metal layer 36a is laminated is formed.

  Thereafter, as shown in FIG. 14C, after removing the resist pattern 1002, a part of each slope is removed from each slope side of the trapezoidal metal layer 36a by an ion milling method or the like. A triangular metal layer 36a is formed.

  Subsequently, as shown in FIG. 14D, a dielectric film 35b made of the same material as the dielectric film 35a is formed on the dielectric film 35a so as to cover the metal layer 36a, and a future medium facing surface is formed. A resist pattern 1003 for forming an end surface of the metal layer 36a is laminated on the side to be formed, and as shown in FIG. 15A, the metal layer 36a is formed on the side opposite to the side on which the medium facing surface is formed in the future. Then, the dielectric film 35b is removed by an ion milling method or the like, and then a dielectric film 35c is formed from the same material as the dielectric film 35b in the removed portion.

  Further, as shown in FIG. 15B, a dielectric film 35d is further laminated on the dielectric films 35b and 35c with the same material as the dielectric film 35b, so that the dielectric film 35a has a rectangular shape. , 35b, 35c, and 35d, the dielectric layer 38a that forms the lower clad and the dielectric layers 35a, 35c, and 35d that constitute the core 35 are completed.

  Next, the condenser lens 35 </ b> L is formed on the core 35. In this formation, first, a resist RE having an opening in the planar area 35L ′ of the condenser lens 35L is formed on the dielectric layer 35d. In the resist RE, about two openings M 'and M' for marks are also formed on the light incident surface side (FIG. 15C). Although a photoresist can be used as the mask, a hard mask such as a metal mask can be used instead.

Thereafter, using this resist RE as a mask, the core (dielectric layers 35d, 35c, 35a) is etched until the surface of the clad 38a is exposed (FIG. 16A).
Further, a high refractive index material HR is deposited on the core (dielectric layers 35d, 35c, 35a), and this high refractive index is formed on the exposed surface of the core and on the lower clad 38a in the opening formed by etching. The material HR is embedded. The high refractive index material HR becomes the condensing lens 35L in the region 35L ′ and the mark region M in the opening M ′ (FIG. 16B). The mark area M is formed in order to observe the incident position of light by image recognition.

  Thereafter, when the resist RE is removed, the high refractive index material HR in a region other than the condenser lens 35L and the mark region M is removed by lift-off, and the surface of the core 35 is exposed (FIG. 16C).

  Further, as shown in FIG. 16D, by further forming an insulating layer (upper clad) 38b with the same material as the insulating layer 38a so as to cover the core 35, the insulating layer 38 as a clad layer is completed. . Then, by wrapping a predetermined distance from the side where the metal layer 36a is exposed, the near-field light emitting unit 36 and the medium facing surface S having a predetermined thickness are formed.

  Through the above steps, the core 35 including the plasmon probe 36 can be formed. The planar waveguide includes a core 35, an upper clad 38b, and a lower clad 38a. Etching includes ion beam etching, reactive ion etching, wet etching, etc., and mask removal includes methods such as wet etching, chemical mechanical polishing, and ashing. In the above-described method, lift-off is used. However, the resist RE is removed in the step immediately before the formation of the condenser lens 35L and the condenser lens is formed by the entire surface sputtering method. You may employ | adopt the method of performing chemical mechanical polishing until it becomes flat.

  Glass materials such as quartz glass are known as materials for the core and cladding, and the refractive index is increased by adding germanium oxide or the like to the core portion, and the refractive index is added to the cladding portion by adding fluorine or boron oxide or the like. Can be reduced. In the condensing lens, the addition amount of germanium oxide or the like for achieving a high refractive index is set higher than in the core.

  Thereafter, as shown in FIG. 4, an electromagnetic coil element 34 is formed by a known method using patterning and sputtering, and thereafter an insulating layer 38 made of alumina or the like is formed, and an electrode pad 371 or the like for connection is formed. Then, the slider 22 is completed by lapping the air bearing surface and the back surface thereof. Thereafter, the electromagnetic coil element 34 and the MR effect element 33 of the slider 22 are tested for each slider to select non-defective products.

  Subsequently, the light source unit 23 is manufactured. First, as shown in FIG. 4, a light source support substrate 230 made of Altic or the like is prepared, and a heat insulating layer 230a, an insulating layer 41, and electrode pads 47 and 48 are formed on the surface thereof by a known method. The light emitting element 40 is fixed on the top with a conductive solder material such as AuSn, and then shaped into a predetermined size by cutting and separating the substrate. Thereby, the light source unit 23 is completed. The light source unit thus obtained is also selected from those which are considered to have a sufficiently long life by observing the characteristics of the light emitting element, in particular, the profile of the driving current by the high-temperature continuous energization test.

  Thereafter, as shown in FIG. 17A, a UV curable adhesive 44a is applied to either or both of the bonding surface 2300 of the light source unit 23, which is a non-defective product, and the back surface 2201 of the slider 22, which is a non-defective product. Examples of the UV curable adhesive include a UV curable epoxy resin and a UV curable acrylic resin.

  Then, as shown in FIG. 17B, after the adhesive surface 2300 of the light source unit 23 and the back surface 2201 of the slider 22 are overlapped, a voltage is applied between the electrode pads 47 and 48 to cause the light emitting element 40 to emit light. At the same time, the photodetector DT is disposed opposite to the light emitting surface 353 of the core 35, and the light source unit 23 and the slider 22 are relatively moved in the direction of the arrow in FIG. The position to be raised is found, and at that position, the UV curable adhesive 44a is cured by irradiating the UV curable adhesive from the outside, thereby aligning the optical axis of the light emitting element with the optical axis of the core 35. In this state, the light source unit 23 and the slider 22 can be bonded.

As described above, in the method of manufacturing the thermally-assisted magnetic head according to the above-described embodiment, the process of depositing the core 35 (35a, 35b, 35c, 35d) on the lower clad 38a (FIG. 15B), A step of etching a part of 35 (FIG. 16A) and a step of forming a condensing lens 35L by depositing a material having a refractive index higher than that of the core 35 in the region removed by the etching (FIG. 16). 16 (B)), a step of forming the upper clad 38b on the core 35 and the condenser lens 35L (FIG. 16D), and a step of forming the plasmon probe 36 on the light emitting surface (FIG. 14A). 16D) and a step of forming an electromagnetic coil 34 (FIG. 7) next to the plasmon probe 36. According to the manufacturing method of the present invention, the condensing lens 35L can be easily formed by the etching and the deposition process of the high refractive index material, so that the heat assist head can be easily manufactured.

  Next, the operation of the heat-assisted magnetic head 21 according to the present embodiment will be described.

  During the writing or reading operation, the thermally-assisted magnetic head 21 floats on the surface of the rotating magnetic disk (medium) 10 with a predetermined flying height hydrodynamically. At this time, the end on the medium facing surface S side of the MR effect element 33 and the electromagnetic coil element 34 faces the magnetic disk 10 through a minute spacing, thereby reading by sensing the data signal magnetic field and applying the data signal magnetic field. Is written by.

  Here, when the data signal is written, the laser light propagating from the light source unit 23 through the core 35 reaches the plasmon probe 36, and near-field light is generated from the plasmon probe 36. This near-field light enables heat-assisted magnetic recording.

By adopting a heat-assisted magnetic recording system, writing is performed on a high coercivity magnetic disk using a thin film magnetic head for perpendicular magnetic recording, and the recording bits are made extremely fine, for example, 1 Tbits / in class ² It may also be possible to achieve recording density.

  In this embodiment, by using the light source unit 23, laser light propagating in a direction parallel to the layer surface of the core 35 can be incident on the light incident surface (end surface) 354 of the core 35 of the slider 22. That is, in the thermally-assisted magnetic head 21 having a configuration in which the integration surface 2202 and the medium facing surface S are perpendicular to each other, laser light having an appropriate size and direction can be reliably supplied. As a result, heat-assisted magnetic recording with high heating efficiency of the recording layer of the magnetic disk can be realized.

  According to the present embodiment, the magnetic head unit 32 is fixed to the slider substrate 220, and the light emitting elements 40 as light sources are separately fixed to the light source support substrate 230. Therefore, the electromagnetic coil fixed to the slider substrate 220 is used. The element 34 and the light emitting element 40 fixed to the light source support substrate 230 are independently tested, and the non-defective slider 22 and the non-defective light source unit 23 are fixed to each other to fix the non-defective heat-assisted magnetism. The head 21 can be manufactured with a high yield.

  Further, since the magnetic head portion 32 is provided on the side surface of the slider substrate 220, the electromagnetic coil element 34, the MR effect element 33, etc. of the magnetic head portion 32 can be easily formed by using a conventional thin film magnetic head manufacturing method. .

  Further, since the light emitting element 40 is located away from the medium facing surface S and in the vicinity of the slider 22, the heat generated from the light emitting element 40 adversely affects the electromagnetic coil element 34, the MR effect element 33, etc., and the light emitting element 40 and the magnetic field. The possibility of contact with the disk 10 is suppressed, and since optical fibers, lenses, mirrors, and the like are not essential, light propagation loss can be reduced, and the structure of the entire magnetic recording apparatus can be simplified.

  In the present embodiment, since the heat insulating layer 230 a is formed on the back surface of the light source support substrate 230, the heat generated from the light emitting element 40 is more difficult to conduct to the slider 22.

  Moreover, in the said embodiment, although the board | substrate made from the same Altick is employ | adopted for the slider board | substrate 220 and the light source support board | substrate 230, it is also possible to use the board | substrate of a different material. Even in this case, if the thermal conductivity of the slider substrate 220 is λs and the thermal conductivity of the light source support substrate 230 is λ1, it is preferable to satisfy λs ≦ λl. Thereby, it becomes easy to let the heat generated by the light emitting element 40 escape to the outside through the light source support substrate 230 while preventing the heat from being transmitted to the slider substrate 220 as much as possible.

  The sizes of the slider 22 and the light source unit 23 are arbitrary. For example, the slider 22 may be a so-called femto slider having a width in the track width direction of 700 μm × length (depth) 850 μm × thickness 230 μm. In this case, the light source unit 23 can have substantially the same width and length. Actually, for example, a typical size of a light emitting element that is normally used is about 250 μm wide × 350 μm long (depth) × 65 μm thick. It is possible to install the light emitting element 40 sufficiently. It is also possible to provide a groove on the bottom surface of the light source support substrate 230 and provide the light emitting element 40 in the groove.

  In addition, in the spot of the far-field image (far field pattern) of the laser light that has reached the light incident surface 354 of the core 35, the diameter in the track width direction is set to about 0.5 to 1.0 μm, for example, and is orthogonal to this diameter. A diameter can be made into about 1-5 micrometers, for example. Correspondingly, the thickness T35 of the core 35 that receives this laser beam is set to about 2 to 10 μm, which is larger than the spot, for example, and the maximum width (W35) of the core 35 in the track width direction is set to about 1 to 200 μm, for example. It is preferable.

  Further, the electromagnetic coil element 34 may be used for longitudinal magnetic recording. In this case, instead of the main magnetic pole layer 340 and the auxiliary magnetic pole layer 344, a lower magnetic pole layer and an upper magnetic pole layer are provided, and further, the writing held between the ends of the lower magnetic pole layer and the upper magnetic pole layer on the medium facing surface S side. A gap layer is provided. Writing is performed by a leakage magnetic field from the position of the write gap layer.

  In addition, the shape of the plasmon probe is not limited to the above-described one, and for example, it is possible to implement a trapezoidal shape in which the apex 36c is flat instead of a triangle. Alternatively, a so-called “bow tie type” structure in which a pair of short sides are arranged so as to face each other with a predetermined distance is also possible.

  FIG. 18 is a perspective view of a plasmon probe 36 having a “bow tie type” structure. A pair of plasmon probes 36 are arranged to face each other along the X axis, and the apexes 36c are abutted with each other with a predetermined interval. In this “bow tie type” structure, a very strong electric field concentration occurs at the center between the apexes 36c, and near-field light is generated.

  Moreover, although the coil layer 342 is one layer in FIG. 4 etc., two or more layers or a helical coil may be sufficient.

  As another embodiment, the plasmon probe 36 may be provided with a minute opening smaller than the wavelength of light on the medium facing surface S side of the core 35.

  Further, the heat insulating layer 230a may be formed on the back surface 2201 of the slider substrate 220, and can be implemented without providing it at all.

  Further, the light source unit 23 and the slider 22 can be bonded by using an adhesive other than the UV curable adhesive, for example, a solder layer such as AuSn used for bonding the light emitting element 40 and the electrode pad 47. is there.

  In addition, in the HGA and hard disk device provided with the heat-assisted magnetic head, stable writing can be recorded at high density.

  All the embodiments described above are illustrative of the present invention and are not intended to be limiting, and the present invention can be implemented in other various modifications and changes. Therefore, the scope of the present invention is defined only by the claims and their equivalents.

1 is a perspective view of a hard disk device according to an embodiment. It is a perspective view of HGA17. FIG. 2 is an enlarged perspective view of the vicinity of a heat-assisted magnetic head 21 shown in FIG. FIG. 4 is a cross-sectional view taken along arrow IV-IV of the thermally assisted magnetic head 21 shown in FIG. 3. 3 is a circuit diagram of a heat-assisted magnetic head 21. FIG. FIG. 3 is a plan view of the main part of the magnetic head viewed from the medium facing surface side. 2 is a perspective view of a main part of a heat-assisted magnetic head 21. FIG. It is explanatory drawing which shows the top view of the core 35, and the kind of condensing lens 35L. It is a perspective view of the core 35 at the time of using a convex lens as an example of the condensing lens 35L. 4 is a perspective view of a plasmon probe 36 as viewed from a medium facing surface S. FIG. 6 is a graph showing the relationship between the wavelength λ (nm) of incident light to the plasmon probe 36 and the near-field light intensity I (au). 6 is a graph showing the relationship between the wavelength λ (nm) of incident light to the plasmon probe 36 and the near-field light intensity I (au). 3 is a perspective view of a light emitting element 40. FIG. 5 is a perspective view for explaining an embodiment of a method for forming a waveguide and a plasmon probe 36. FIG. 5 is a perspective view for explaining an embodiment of a method for forming a waveguide and a plasmon probe 36. FIG. 5 is a perspective view for explaining an embodiment of a method for forming a waveguide and a plasmon probe 36. FIG. It is a perspective view which shows the manufacturing method of a heat-assisted magnetic head. FIG. 6 is a perspective view of a plasmon probe 36 having a “bow tie type” structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hard disk apparatus, 10 ... Magnetic disk (recording medium), 17 ... Head gimbal assembly (HGA), 20 ... Suspension, 21 ... Thermally assisted magnetic head, 22 ... Slider, 220 ... Slider substrate, 2202 ... Integration surface, 23 ... Light source unit, 230 ... light source support substrate, 32 ... magnetic head, 33 ... MR effect element (magnetic detection element), 34 ... electromagnetic coil element (magnetic recording element), 35 ... waveguide, 354 ... light incident surface (end face) , 36 ... Plasmon probe, 40 ... Light emitting element (light source), 400 ... Light exit end, S ... Medium facing surface.

Claims (6)

In heat-assisted magnetic head,
A waveguide core having a light incident surface and a light exit surface facing the magnetic recording medium;
A plasmon probe provided on the light exit surface;
A magnetic recording element located next to the plasmon probe;
A condenser lens embedded in the core;
With
The light condensing position by the condensing lens and the position of the light exit surface are shifted along the optical axis of the core,
The heat-assisted magnetic head according to claim 1, wherein a position of the light emitting surface coincides with a focal position of the condenser lens.   The thermally assisted magnetic head according to claim 1, wherein the condenser lens is a convex lens, a binary lens, or a Fresnel lens. The condensing lens is a convex lens, and its refractive index is higher than the refractive index of the core,
When the optical axis of the core is the Z axis, the thickness direction of the core is the X axis, and the width direction is the Y axis,
The convex lens is
A light incident curved surface composed of line segments parallel to the X axis and protruding in the light incident surface direction with respect to the XY plane;
A light exit curved surface composed of line segments parallel to the X axis and projecting in the light exit surface direction with respect to the XY plane;
The heat-assisted magnetic head according to claim 1, comprising: The thermally assisted magnetic head according to any one of claims 1 to 3,
A suspension supporting the thermally-assisted magnetic head;
Head gimbal assembly with A head gimbal assembly according to claim 4;
A magnetic recording medium facing the head gimbal assembly;
Hard disk device with In the manufacturing method of the thermally assisted magnetic head which manufactures the thermally assisted magnetic head according to any one of claims 1 to 3 ,
Depositing the core on the lower cladding;
Etching a portion of the core;
Forming the condenser lens by depositing a material having a higher refractive index than the core in the region removed by the etching; and
Forming an upper cladding on the core and the condenser lens;
Forming the plasmon probe on the light exit surface of the core;
Forming the magnetic recording element next to the plasmon probe;
A method of manufacturing a thermally assisted magnetic head, comprising:

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