Patent Application
20130139378
1. Field of the Invention
The present invention relates to a method of manufacturing a thermally-assisted magnetic recording head used in a thermally-assisted magnetic recording in which near-field light is applied to a magnetic recording medium to lower a coercivity thereof so as to record information, and an alignment apparatus used therefor.
2. Description of Related Art
A magnetic disk device in the related art is used for writing and reading magnetic information (hereinafter, simply referred to as information). The magnetic disk device is provided with, in the housing thereof, a magnetic disk in which information is stored, and a magnetic read write head which records information into the magnetic disk and reproduces information stored in the magnetic disk. The magnetic disk is supported by a rotary shaft of a spindle motor, which is fixed to the housing, and rotates around the rotary shaft. On the other hand, the magnetic read write head is formed on a side surface of a magnetic head slider provided on one end of a suspension, and the magnetic read write head includes a magnetic write element and a magnetic read element which have an air bearing surface (ABS) facing the magnetic disk. In particular, as the magnetic read element, a magneto-resistive (MR) element exhibiting magneto-resistive effect is generally used. The other end of the suspension is attached to an edge of an arm which is rotatably supported by a fixed shaft installed upright in the housing.
When the magnetic disk device is not operated, namely, when the magnetic disk does not rotate, the magnetic read write head is not located over the magnetic disk and is pulled off to the position away from the magnetic disk (unload state). When the magnetic disk device is driven and the magnetic disk starts to rotate, the magnetic read write head is changed to a state where the magnetic read write head is located at a predetermined position over the magnetic disk together with the suspension (load state). When the rotation number of the magnetic disk reaches a predetermined number, the magnetic head slider is stabilized in a state of slightly floating over the surface of the magnetic disk due to the balance of positive pressure and negative pressure. Thus, the information is accurately recorded and reproduced.
In recent years, with a progress in higher recording density (higher capacity) of the magnetic disk, an improvement in performance of the magnetic read write head and the magnetic disk has been demanded. The magnetic disk is a discontinuous medium including collected magnetic microparticles, and each magnetic microparicle has a single-domain structure. In the magnetic disk, one recording bit is configured by a plurality of magnetic microparticles. Since the asperity of a boundary between adjacent recording bits is necessary to be small in order to increase the recording density, the magnetic microparticles need to be made small. However, if the magnetic microparticles are small in size, thermal stability of the magnetization of the magnetic micorparticles is lowered with decreasing the volume of the magnetic maicroparticles. To solve the difficulty, increasing anisotropic energy of the magnetic microparticles is effective. However, increasing the anisotropic energy of the magnetic microparticles leads to increase in the coercivity of the magnetic disk. As a result, difficulty occurs in the information writing using the existing magnetic head.
As a method to solve the above-described difficulty, a so-called thermally-assisted magnetic recording has been proposed. In the method, a magnetic recording medium with large coercivity is used, and when information is written, heat is applied together with the magnetic field to a portion of the magnetic recording medium where the information is recorded to increase the temperature and to lower the coercivity, thereby writing the information. Hereinafter, the magnetic head used in the thermally-assisted magnetic recording is referred to as a thermally-assisted magnetic recording head.
In the thermally-assisted magnetic recording, near-field light is generally used for applying heat to the magnetic recording medium. As a method of generating near-field light, a method using a near-field light probe that is a metal strip, namely, so-called plasmon generator is generally known. In the plasmon generator, plasmons are generated by excitation by incident light from the outside, and as a result, near-field light is generated. As for the arrangement of the light source which is required to supply the incident light from the outside, various configurations have been proposed up to now. The applicant has been proposed a thermally-assisted magnetic recording head having a “composite slider structure” in which a light source unit including a laser oscillator is bonded to a surface of the slider formed with a magnetic write element which is opposite to the surface of the ABS. The “composite slider structure” is disclosed in U.S. Patent Application Publication No. 2008/043360 specification and U.S. Patent Application Publication No. 2009/052078 specification.
In the method of performing thermally-assisted magnetic recording with use of a plasmon generator, it is important to stably supply light with sufficient intensity to a desired position on the magnetic recording medium. Therefore, it is necessary to secure high alignment accuracy for fixing a light source unit to a slider. Reduction in alignment accuracy causes reduction in heating efficiency with respect to a magnetic recording medium, and it is serious issue in thermally-assisted magnetic recording. From the reason, it is desirable to provide a method capable of easily and accurately manufacturing a thermally-assisted magnetic recording head excellent in write efficiency. Moreover, it is also desirable to provide an alignment apparatus suitable for such a method of manufacturing a thermally-assisted magnetic recording head.
A method of manufacturing a thermally-assisted magnetic recording head according to an embodiment of the invention includes steps of the following (A1) to (A4):
(A1) providing a light source unit including a light source;
(A2) providing a substrate having a thermally-assisted magnetic recording head section thereon, the thermally-assisted magnetic recording head section including a magnetic pole, a plasmon generator, and an optical waveguide;
(A3) inserting a metal between the light source unit and the substrate, and thus allowing the metal to be melted; and
(A4) performing an alignment between the light source unit and the thermally-assisted magnetic recording head section under application of pressure in a direction that allows the light source unit and the substrate to approach each other, while maintaining the metal melted.
In the method of manufacturing a thermally-assisted magnetic recording head according to the embodiment of the invention, the alignment between the light source unit and the substrate is performed in a state where the metal in the melting state is inserted between the light source unit and the substrate, under application of pressure in a direction that allows the light source unit and the substrate to approach each other. Accordingly, a relative distance between the light source and the optical waveguide is further reduced while securing high alignment accuracy between the light source and the optical waveguide. As a result, a thermally-assisted magnetic recording head exhibiting more excellent operation property is obtainable with reduced power consumption.
An apparatus of manufacturing a thermally-assisted magnetic recording head according to an embodiment of the invention is for manufacturing a thermally-assisted magnetic recording head including a substrate and a light source unit, the substrate having, thereon, a thermally-assisted magnetic recording head section that includes a magnetic pole, a plasmon generator, and an optical waveguide, the light source unit having a light source and being bonded to the substrate with a metal in between, and the apparatus includes the following (B1) to (B4):
(B1) a positioning section adjusting a relative position between the light source unit and the thermally-assisted magnetic recording head section;
(B2) a biasing mechanism applying, to the light source unit and the substrate, pressure in a direction that allows the light source unit and the substrate to approach each other;
(B3) a heating mechanism heating the metal to be melted; and
(B4) a controller controlling an operation of the positioning section, the biasing mechanism, and the heating mechanism.
According to the apparatus of manufacturing a thermally-assisted magnetic recording head of the embodiment of the invention, by the operation control of the controller, the relative position between the light source unit and the thermally-assisted magnetic recording head section is adjustable under application of the pressure in the direction that allows the light source unit and the substrate to approach each other, while maintaining the metal melted. Therefore, bonding which allows the distance between the light source and the optical waveguide to be reduced is achievable with securing high alignment accuracy between the light source and the optical waveguide. As a result, a thermally-assisted magnetic recording head which exhibits more excellent operation property is obtainable with reduced power consumption.
In the method of manufacturing a thermally-assisted magnetic recording head according to the embodiment of the invention, the application of the pressure is preferably continued until the melted metal is solidified because bonding with high accuracy is more surely performed. Moreover, in the state where the metal is melted, the light source unit and the substrate are preferably allowed to oscillate in a direction different from the direction in which the pressure is applied because the relative distance between the light source and the substrate is reduced more rapidly. In addition, the pressure may be applied by pressing one of the light source unit and the substrate against the other, while a surface of the one of the light source unit and the substrate is sucked by a suction member, the surface intersecting a surface bonded with the other. In this case, the pressure adjustment is preferably performed by varying the suction force of the suction member, because in doing so, for example, a possibility that excessive pressure is applied to the substrate and the light source unit is eliminated. Furthermore, preferably, the light source unit provided includes a supporting member on which the light source is mounted, and inserting of the metal between the supporting member and the substrate is performed and follows application of laser light to the supporting member to melt the meal. This is because prompt bonding process is achievable, and thus error in the relative position between the light source unit and the slider is less likely to occur.
Hereinafter, a preferred embodiment of the invention will be described in detail with reference to drawings.
First, referring to
Next, the magnetic read write head section 10 will be described in more detail with reference to
The read head section 14 performs a read process using magneto-resistive effect (MR). The read head section 14 is configured by stacking, for example, a lower shield layer 21, an MR element 22, and an upper shield layer 23 in order on the insulating layer 13.
The lower shield layer 21 and the upper shield layer 23 are respectively formed of a soft magnetic metal material such as NiFe (nickel iron alloy), and are disposed to face each other with the MR element 22 in between in the stacking direction (in Z-axis direction). As a result, the lower shield layer 21 and the upper shield layer 23 each exhibit a function to protect the MR element 22 from the influence of unnecessary magnetic field.
One end surface of the MR element 22 is exposed at the ABS 11S, and the other end surfaces thereof are in contact with an insulating layer 24 filling a space between the lower shield layer 21 and the upper shield layer 23. The insulating layer 24 is formed of an insulating material such as Al2O3 (aluminum oxide), AlN (aluminum nitride), SiO2 (silicon dioxide), or DLC (diamond-like carbon).
The MR element 22 functions as a sensor for reading magnetic information written in the magnetic disk 2. Note that in the embodiment, in a direction (Y-axis direction) orthogonal to the ABS 11S, a direction toward ABS 11S with the MR element 22 as a base or a position near the ABS 11S is called “front side”. A direction toward opposite side from the ABS 11S with the MR element 22 as a base or a position away from the ABS 11S is called “back side”. The MR element 22 is, for example, a CPP (current perpendicular to plane)—GMR (giant magnetoresistive) element whose sense current flows inside thereof in a stacking direction. The lower shield layer 21 and the upper shield layer 23 each function as an electrode to supply the sense current to the MR element 22.
In the read head section 14 with such a structure, a magnetization direction of a free layer (not illustrated) included in the MR element 22 changes depending on a signal magnetic field from the magnetic disk 2. Thus, the magnetization direction of the free layer shows a change relative to a magnetization direction of a pinned layer (not illustrated) also included in the MR element 22. When the sense current is allowed to flow through the MR element 22, the relative change in the magnetization direction appears as the change of the electric resistance. Therefore, the read head section 14 detects the signal magnetic field using the change to read the magnetic information.
On the read head section 14, an insulating layer 25, an intermediate shield layer 26, and an insulating layer 27 are stacked in order. The intermediate shield layer 26 functions to prevent the MR element 22 from being affected by a magnetic field which is generated in the write head section 16, and is formed of, for example, a soft magnetic metal material such as NiFe. The insulating layers 25 and 27 are formed of the similar material to the insulating layer 24.
The write head section 16 is a vertical magnetic recording head performing a recording process of thermally-assisted magnetic recording system. The write head section 16 has, for example, a lower yoke layer 28, a leading shield 29 and a connecting layer 30, a clad 31L, a waveguide 32, clads 33A and 33B, and a clad 31U in order on the insulating layer 27. The clads 33A and 33B configure a first clad pair sandwiching the waveguide 32 in the direction across tracks (in the X-axis direction). On the other hand, the clads 31L and 31U configure a second clad pair sandwiching the waveguide 32 in the thickness direction (in the Z-axis direction). Note that the leading shield 29 may be omitted from the structure.
The waveguide 32 is made of a dielectric material allowing laser light to pass therethrough. Examples of the constituent material of the waveguide 32 include SiC, DLC, TiOx (titanium oxide), TaOx (tantalum oxide), SiNx (silicon nitride), SiOxNy (silicon oxynitride), Si (silicon), ZnSe (zinc selenide), NbOx (niobium oxide), GaP (gallium phosphide), ZnS (zinc sulfide), ZnTe (zinc telluride), CrOx (chromium oxide), FeOx (iron oxide), CuOx (copper oxide), SrTiOx (strontium titanate), BaTiOx (barium titanate), Ge (germanium), and C (diamond). The clads 33A, 33B, 31L, and 31U are made of a dielectric material having a refractive index with respect to laser light propagating through the waveguide 32, lower than that of a constituent material of the waveguide 32. In terms of the refractive index with respect to laser light propagating through the waveguide 32, the dielectric material constituting the clads 33A and 33B and the dielectric material constituting the clads 31L and 31U may be the same or different from each other. Examples of the dielectric material constituting the clads 33A, 33B, 31L, and 31U include SiOx (silicon oxide), Al2O3 (aluminum oxide), AlN (aluminum nitride), and Al2O3.
The lower yoke layer 28, the leading shield 29, and the connecting layer 30 are each made of a soft magnetic metal material such as NiFe. The leading shield 29 is located at the frontmost end of the upper surface of the lower yoke layer 28 so that one end surface of the leading shield 29 is exposed at the ABS 11S. The connecting layer 30 is located backward of the leading shield 29 on the upper surface of the lower yoke layer 28. The clad 31L is made of a dielectric material having a refractive index, with respect to laser light propagating through the waveguide 32, lower than that of the waveguide 32, and is provided to cover the lower yoke layer 28, the leading shield 29, and the connecting layer 30. The waveguide 32 provided on the clad 31L extends in a direction (Y-axis direction) orthogonal to the ABS 11S, one end surface of the waveguide 32 is exposed at the ABS 11S, and the other end surface is exposed at the backward thereof. Note that the front end surface of the waveguide 32 may be located at a receded position from the ABS 11S without being exposed at the ABS 11S. In the waveguide 32, the shape of a section surface parallel to the ABS 11S is, for example, a rectangular shape, but may be the other shapes.
The write head section 16 further includes a plasmon generator 34 provided above the front end of the waveguide 32 through the clad 31U, and a magnetic pole 35 provided to be in contact with the upper surface of the plasmon generator 34. The plasmon generator 34 and the magnetic pole 35 are arranged so that one end surface of each of the plasmon generator 34 and the magnetic pole 35 is exposed at the ABS 11S. The magnetic pole 35 has a structure in which a first layer 351 and a second layer 352 are stacked in order on the plasmon generator 34, for example. Both the first layer 351 and the second layer 352 are configured of a magnetic material with high saturation flux density such as iron-based alloy. Examples of the iron-based alloy include FeCo (iron cobalt alloy), FeNi (iron nickel alloy), and FeCoNi (iron cobalt nickel alloy). The plasmon generator 34 generates near-field light NF (described later) from the ABS 11S, based on the laser light which has propagated through the waveguide 32. The magnetic pole 35 stores therein magnetic flux generated in a coil 41 (described later), releases the magnetic flux from the ABS 11S, thereby generating a write magnetic field for writing magnetic information into the magnetic disk 2. The plasmon generator 34 and the first layer 351 are embedded in the clad layer 33.
The write head section 16 further includes a connecting layer 36 embedded in the clad layer 33 at the backward of the plasmon generator 34 and the magnetic pole 35, and a connecting layer 37 provided to be in contact with the upper surface of the connecting layer 36. Both the connecting layers 36 and 37 are arranged above the connecting layer 30 and are formed of a soft magnetic metal material such as NiFe.
The write head section 16 includes two connecting sections 40A and 40B (
As illustrated in
In the write head section 16 with such a structure, by the write current flowing through the coil 41, magnetic flux is generated inside a magnetic path which is mainly configured by the leading shield 29, the lower yoke layer 28, the connecting layer 30, the connecting sections 40A and 40B, the connecting layers 36 and 37, the upper yoke layer 43, and the magnetic pole 35. Accordingly, a signal magnetic field is generated near the end surface of the magnetic pole 35 exposed at the ABS 11S, and the signal magnetic field reaches a predetermined region of the recording surface of the magnetic disk 2.
Further, in the magnetic read write head section 10, the clad 17 made of similar material to the clad 31U is formed to cover the entire upper surface of the write head section 16.
The light source unit 50 provided at the backward of the magnetic read write head section 10 includes a laser diode 60 as a light source emitting laser light, and a rectangular-solid supporting member 51 supporting the laser diode 60, as illustrated in
The supporting member 51 is formed of, for example, a ceramic material such as Al2O3.TiC. As illustrated in
Laser diodes generally used for communication, for optical disc storage, or for material analysis, for example, InP-based, GaAs-based, or GaN-based laser diodes, may be used as the laser diode 60. The wavelength of the laser light emitted from the laser diode 60 may be any value within the range of, for example, 375 nm to 1.7 μm. Specifically, examples of such a laser diode include a laser diode of InGaAsP/InP quaternary mixed crystal with the emission wavelength region of 1.2 to 1.67 μm. As illustrated in
Next, referring to
As illustrated in
As illustrated in
As illustrated in
A V-shaped groove is provided in the mid-portion C34 of the first portion 34A. In other words, a pair of sidewalls 34A1 and 34A2 which respectively extend in a direction orthogonal to the ABS 11S is connected with each other at the edge 344 so as to form a V-shape having a vertex angle α on a section surface parallel to the ABS 11S. To increase the generation efficiency of the near-field light, the vertex angle α is preferably within a range of approximately 55° to 75°, for example. The edge 344 is a boundary portion between the pair of sidewalls 34A1 and 34A2, and extends in the Y-axis direction from a pointed edge 34G exposed at the ABS 11S as a base point to the second portion 34B. The pointed edge 34G is a portion generating the near-field light. The edge 344 faces the evanescent light generating surface 32C of the waveguide 32, and the sidewalls 34A1 and 34A2 are tilted so that the relative distance therebetween in X-axis direction becomes wider with increasing distance from the waveguide 32 with the edge 344 being a base point.
In the wing portions W34 of the first portion 34A, a pair of fringes 34A3 and 34A4 is provided so that one end of each of the fringes 34A3 and 34A4 in the X-axis direction is connected to an end portion on the opposite side from the edge 344 of the sidewalls 34A1 and 34A2, respectively. For example, the pair of the fringes 34A3 and 34A4 extends along a plane (XY-plane) orthogonal to the ABS 11S and parallel to the X-axis direction. The sidewalls 34A1 and 34A2 and the fringes 34A3 and 34A4 have a front end surface 342 exposed at the ABS 11S (
As illustrated in
The third portion 34C includes a bottom portion 34C1, sidewalls 34C2 and 34C3, a wall 34C4, and fringes 34C5, 34C6, and 34C7. The bottom portion 34C1 is provided so as to extend continuously from the bottom portion 34B1 of the second portion 34B in the XY-plane. The sidewalls 34C2 and 34C3 are respectively connected to the sidewalls 34B2 and 34B3 of the second portion 34B, and extend to be orthogonal to the ABS 11S. The sidewalls 34C2 and 34C3 are tilted so that the relative distance (the distance in the X-axis direction) therebetween becomes wider with increasing distance from the waveguide 32, with the connecting portion to the bottom portion 34C1 being a base point. The wall 34C4 couples the bottom portion 34C1 and the rear end portion of each of the sidewalls 34C2 and 34C3. The fringes 34C5 and 34C6 are respectively coupled to the fringes 34B4 and 34B5 of the second portion 34B, and extend to be orthogonal to the ABS 11S. The fringe 34C7 couples the fringes 34C5 and 34C6 and the rear end portion of the wall 34C4. The section surface of each of the sidewalls 34C2 and 34C3 and the fringes 34C5 and 34C6, which is orthogonal to the corresponding extending direction, preferably have the similar shape to that of the section surface of each of the sidewalls 34A1 and 34A2 and the fringes 34A3 and 34A4 of the first portion 34A, for example. Note that the wall 34C4 and the fringe 34C7 may not be provided.
As illustrated in
The surfaces of the bottom portions 34B1 and 34C1 facing the evanescent light generating surface 32C of the waveguide 32 with a predetermined distance are a first surface 341B and a second surface 341C which form a surface plasmon exciting surface 341 as illustrated in
The magnetic pole 35 has an end surface 35T exposed at the ABS 11S as illustrated in
The first layer 351 of the magnetic pole 35 is contained in a space formed by the first portion 34A, the second portion 34B, and the third portion 34C of the plasmon generator 34. Specifically, the first layer 351 has a first portion 351A occupying a space formed by the first portion 34A, a second portion 351B occupying a space formed by the second portion 34B, and a third portion 351C occupying a space formed by the third portion 34C. The first portion 351A has a triangular prism shape closely contacting the sidewalls 34A1 and 34A2 of the first portion 34A of the plasmon generator 34, and the area of the section surface parallel to the ABS 11S is constant. In the X-axis direction, the width of the first portion 351A is desirably smaller than that of the end surface 32B of the waveguide 32. Furthermore, the width of the first portion 351A is desirably smaller than that of the mid-portion C34 of the first portion 34A. This is because the maximum intensity of the write magnetic field from the magnetic pole 35 is increased in both cases. The end surface 351T of the first portion 351A has a pointed edge 35C located at a vertex opposite to the second layer 352.
The second portion 351B is closely contacted with the sidewalls 34B2 and 34B3 and the bottom portion 34B1 of the second portion 34B of the plasmon generator 34. The width of the second portion 351B becomes wider with increasing the distance from the ABS 11S in the X-axis direction, and becomes wider with increasing the distance from the waveguide 32 in the Z-axis direction. The third portion 351C is closely contacted with the sidewalls 34C2 and 34C3 and the bottom portion 34C1 of the third portion 34C of the plasmon generator 34. The width of the third portion 351C in the X-axis direction is constant in the Y-axis direction, and becomes wider with increasing the distance from the waveguide 32 in the Z-axis direction.
As illustrated in
In addition to
(3-1. Method of Manufacturing Magnetic Read Write Head Section)
First, as illustrated in
The magnetic read write head section 10 is mainly manufactured by sequentially forming and stacking a series of components by using an existing thin film process. Examples of the existing thin film process include a film forming technique such as an electrolytic plating and a sputtering, patterning technique such as a photolithography, etching technique such as dry etching and wet etching, and polishing technique such as chemical mechanical polishing (CMP).
Herein, first, the insulating layer 13 is formed on the slider 11. Next, the lower shield layer 21, the MR element 22 and the insulating layer 24, and the upper shield layer 23 are formed by stacking in this order on the insulating layer 13 to form the read head section 14. Subsequently, the insulating layer 25, the intermediate shield layer 26, and the insulating layer 27 are stacked in order on the read head section 14.
After that, the lower yoke layer 28, the leading shield 29 and the connecting layer 30, the clad 31L, the waveguide 32, the clads 33A and 33B, the clad 31U, the plasmon generator 34, the magnetic pole 35, and the connecting layers 36 and 37 are formed in order on the insulating layer 27. Note that the formation of the leading shield 29 may be omitted. Further, by performing a planarization treatment after the insulating layer 38 is formed to cover the entire surface, the upper surfaces of the magnetic pole 35, the insulating layer 38, and the connecting layer 37 are planarized. Subsequently, the coil 41 embedded by the insulating layers 39 and 42 is formed. Moreover, the upper yoke layer 43 connected with the magnetic pole 35 and the connecting layer 37 is formed to complete the write head section 16. After that, the clad layer 17 is formed on the write head section 16, and by using CMP or the like, the side surface of the stacked structure from the slider 11 to the clad layer 17 is totally polished to form the ABS 11S. As a result, the plurality of magnetic read write head sections 10 is formed in an array on the wafer 11ZZ (
After that, as illustrated in
(3-2. Method of Bonding Slider to Light Source Unit)
Next, the light source unit 50 is provided, and is bonded to the bar 11Z at respective predetermined positions with use of the alignment apparatus 70 illustrated in
Hereinafter, a method of bonding the light source unit 50 to the bar 11Z will be described specifically with reference to
Next, the bar 11Z is arranged on the tray 72 of the alignment apparatus 70, and the suction nozzle 71 of the alignment apparatus 70 sucks and holds the light source unit 50 (step S102). After that, the light source unit 50 held by the suction nozzle 71 is fed above the magnetic read write head section 10 to be bonded (step S103). At this time, the bonding surface 51A of the supporting member 51 is opposed to the back surface 11BZ of the bar 11Z with a predetermined distance therebetween. Note that the suction nozzle 71 is arranged so as to suck the surface intersecting the bonding surface 51A of the supporting member 51, for example, a back surface 51E.
Subsequently, the light source unit 50 is moved in the Y-axis direction, and as illustrated in
Further, the light source unit 50 held by the suction nozzle 71 is pressed against the bar 11Z by predetermined pressure (step S105). At this time, the above described pressure may be adjusted by varying the suction force of the suction nozzle 71. The pressure at this time is determined by the suction force of the suction nozzle 71, and is approximately 10 gram-weight, for example. Moreover, since the suction nozzle 71 is supplied with the force which sucks the back surface 51E intersecting the bonding surface 51A and moves the suction nozzle 71 in a direction along the back surface 51E (in this case, +Y direction), there is no possibility that the pressure more than necessary is applied to the light source unit 50 and the bar 11Z. This is because, even if the force exceeding the suction force is applied to the suction nozzle 71, the suction surface 71T of the suction nozzle 71 glides on the back surface 51E of the supporting member 51, and thus the load exceeding the suction force is not applied to the supporting member 51 substantially.
Next, as illustrated in
The laser beam LB is applied from the light source 75 provided outside to the supporting member 51 from obliquely rearward as illustrated in
As illustrated in
The adhesive layer 58 receives energy through heat conduction from the supporting member 51 which is heated by irradiation of the laser beam LB, and then the adhesive layer 58 is melted. The alignment (position adjustment) between the light source unit 50, the bar 11Z, and the element forming layer 12 is performed as described below while maintaining the state where the adhesive layer 58 is melted and the state where the application of the pressure to the bonding surface 51A is continued (step S107). First, based on the instruction from the controller 74, a predetermined voltage is applied between the terminal electrodes 610 and 611 of the laser diode 60 to emit a laser beam 77 from the emission center 62A of the active layer 62 (
After that, when the irradiation of the laser beam LB is stopped, the melted adhesive layer 58 is rapidly solidified (step S108). As a result, the supporting member 51 of the light source unit 50 and the slider 11 are bonded with accurate positional relationship. Incidentally, the irradiation of the laser beam LB is performed in a time of, for example, about 1.0 to 20.0 s.
Incidentally, when the diameter of the laser beam LB is set to 100 μm, the irradiated position P is desirably set at a position of 150 μm or less apart from the back surface 11BZ of the bar 11Z. In addition, the laser beam LB is desirably applied not to the back surface 11BZ of the bar 11Z but to the side surface 51B of the supporting member 51 with all amount in order to prevent the bar 11Z from being damaged. Note that the angle θ2 may be 0°. In this case, the irradiated position P is lowered in position (close to the back surface 11BZ) so that the adhesive layer 58 is allowed to be efficiently heated. Moreover, only S-polarized light may be applied as the laser beam LB. In this case, a polarizing plate PP is arranged between the light source (not illustrated) and the supporting member 51 to block P-polarized light, and the S-polarized light is allowed to enter the supporting member 51 at a Brewster's angle (for example 75°) which is determined from the refractive index of a material (for example, Si) corresponding to the wavelength of the laser beam LB. As a result, generation of the reflected light RL on the irradiated plane (side surface 51B) is allowed to be prevented. Moreover, to prevent the generation of the reflected light on the side surface 51B, the side surface 51B may be a rough surface (for example, surface roughness Rz=0.2 to 0.8 μm).
After the adhesive layer 58 is solidified due to the irradiation stop of the laser beam LB, the pressure applied to the bonding surface 51A is released by terminating suction of the light source unit 50 by the suction nozzle 71. In such a way, the manufacture of the magnetic head device 4A is completed.
Next, referring to
Herein, the control LSI 100 provides write data and a write control signal to the write gate 111. Moreover, the control LSI 100 provides a read control signal to the constant current circuit 121 and the demodulation circuit 123, and receives the read data output from the demodulation circuit 123. In addition, the control LSI 100 provides a laser ON/OFF signal and an operation current control signal to the laser control circuit 131.
The temperature detector 132 detects the temperature of the magnetic recording layer of the magnetic disk 2 to transmit the temperature information to the control LSI 100.
The ROM 101 stores therein a control table and the like to control an operation current value to be supplied to the laser diode 60.
At the time of write operation, the control LSI 100 supplies the write data to the write gate 111. The write gate 111 supplies the write data to the write circuit 112 only when the write control signal instructs write operation. The write circuit 112 allows the write current to flow through the coil 41 according to the write data. As a result, write magnetic field is generated from the magnetic pole 35, and data is written into the magnetic recording layer of the magnetic disk 2 by the write magnetic field.
At the time of read operation, the constant current circuit 121 supplies a constant sense current to the MR element 22 only when the read control signal instructs the read operation. The output voltage of the MR element 22 is amplified by the amplifier 122, and is then received by the demodulation circuit 123. The demodulation circuit 123 demodulates the output of the amplifier 122 to generate read data to be provided to the control LSI 100 when the read control signal instructs the read operation.
The laser control circuit 131 controls the supply of the operation current to the laser diode 60 based on the laser ON/OFF signal, and controls the value of the operation current supplied to the laser diode 60 based on the operation current control signal. The operation current equal to or larger than the oscillation threshold value is supplied to the laser diode 60 by the control of the laser control circuit 131 when the laser ON/OFF signal instructs the ON operation. As a result, the laser light is emitted from the laser diode 60 and then propagates through the waveguide 32. Subsequently, the near-field light NF (described later) is generated from the pointed edge 34G of the plasmon generator 34, a part of the magnetic recording layer of the magnetic disk 2 is heated by the near-field light NF, and thus the coercivity in the heated part is lowered. At the time of writing, the write magnetic field generated from the magnetic pole 35 is applied to the part of the magnetic recording layer with lowered coercivity, and therefore data recording is performed.
The control LSI 100 determines the value of the operation current of the laser diode 60 with reference to the control table stored in the ROM 101, based on the temperature and the like of the magnetic recording layer of the magnetic disk 2 measured by the temperature detector 132, and controls the laser control circuit 131 with use of the operation current control signal so that the operation current of the value is supplied to the laser diode 60. The control table includes, for example, the oscillation threshold value of the laser diode 60 and data indicating temperature dependency of light output-operation current property. The control table may further include data indicating a relationship between the operation current value and the increased amount of the temperature of the magnetic recording layer heated by the near-field light NF, and data indicating temperature dependency of the coercivity of the magnetic recording layer.
The control circuit illustrated in
Subsequently, a principle of near-field light generation in the embodiment and a principle of thermally-assisted magnetic recoding with use of the near-field light will be described with reference to
The laser beam which has been emitted from the laser diode 60 propagates through the waveguide 32 to reach near the plasmon generator 34. At this time, laser light 45 is totally reflected by the evanescent light generating surface 32C that is an interface between the waveguide 32 and the buffer section 33A, and therefore evanescent light 46 (
It is considered that following first and second principals lead to the increase of the electric field intensity of the plasmons on the first surface 341B. First, the description is made for the first principle. In the embodiment, on the metal surface of the surface plasmon exciting surface 341, the surface plasmons 47 are excited by the evanescent light 46 generated from the evanescent light generating surface 32C. The surface plasmons 47 propagate on the surface plasmon exciting surface 341 toward the pointed edge 34G. The wave number of the surface plasmons 47 propagating on the first surface 341B is gradually increased with decreasing the width of the first surface 341B in the X-axis direction, that is, toward the ABS 11S. As the wave number of the surface plasmons 47 is increased, the propagating speed of the surface plasmons 47 is decreased. As a result, the energy density of the surface plasmons 47 is increased to increase the electric field intensity of the surface plasmons 47.
Next, the description is made for the second principle. When the surface plasmons 47 propagate on the surface plasmon exciting surface 341 toward the pointed edge 34G, a part of the surface plasmons 47 collide with the edge rims 341B1 and 341B2 of the first surface 341B and is scattered, and accordingly a plurality of plasmons with different wave numbers is generated. A part of the plurality of the plasmons thus generated is converted into the edge plasmons 48 whose wave number is larger than that of the surface plasmons propagating on the plane. In such a way, the surface plasmons 47 are gradually converted into the edge plasmons 48 propagating along the edge rims 341B1 and 341B2, and accordingly, the electric field intensity of the edge plasmons 48 is gradually increased. In addition, the edge plasmons 48 have a larger wave number and slower propagating speed compared with the surface plasmons propagating on the plane. Therefore, the surface plasmons 47 are converted into the edge plasmons 48 to increase the energy density of the plasmons. Further, on the first surface 341B, the surface plasmons 47 are converted into the edge plasmons 48 as described above, and new surface plasmons 47 are also generated based on the evanescent light 46 emitted from the evanescent light generating surface 32C. The new surface plasmons 47 are also converted into the edge plasmons 48. In this way, the electric field intensity of the edge plasmons 48 is increased. The edge plasmons 48 are converted into the edge plasmons 49 propagating through the edge 344. Therefore, the edge plasmons 49 are obtainable which have the increased electric field intensity compared with the surface plasmons 47 at the beginning of generation.
In the embodiment, on the first surface 341B, the surface plasmons 47 propagating on the plane coexist with the edge plasmons 48 whose wave number is larger than that of the surface plasmons 47. It is considered that, on the first surface 341B, the increase of the electric field intensity of both the surface plasmons 47 and the edge plasmons 48 occurs due to the first and second principals described above. Accordingly, in the embodiment, compared with a case where one of the first and second principals is effective, the electric field intensity of the plasmons may be further increased.
In the embodiment, as described above, by the operation control by the controller 74, the relative position between the light source unit 50 and the thermally-assisted magnetic recording head section 10 is adjustable under application of pressure in a direction that allows the light source unit 50 and the bar 11B to approach each other, while maintaining the adhesive layer 58 melted. Therefore, the bonding which allows the distance between the emission center 62A of the laser diode 60 and the end surface 32A of the optical waveguide 32 to be reduced is achievable with securing high alignment accuracy between the laser diode 60 as the light source and the optical waveguide 32.
In the embodiment, since the application of the pressure to the bonding surface 51A is continued until the melted adhesive layer 58 is solidified, the bonding with high accuracy is allowed to be performed more surely. Moreover, at the time of performing position adjustment, in the state where the adhesive layer 58 is melted, when the light source unit 50 and the substrate, or the light source unit 50 or the bar 11Z are allowed to oscillate, for example, in a direction parallel to the XZ plane, the relative distance between the supporting member 51 and the bar 11Z is reduced more rapidly. In addition, the adhesive layer 58 is heated by the irradiation of the laser beam LB so that the melting state of the adhesive layer 58 is easily controlled and the rapid bonding treatment is achievable. Accordingly, error in the relative position between the light source unit 50 and the slider 11 is less likely to occur.
As described above, according to the magnetic read write head section 10 of the embodiment, as a result of the accurate position adjustment, accuracy of the write position to the predetermined region of the magnetic recording medium is allowed to be improved, and thus, the magnetic recording with higher density is achievable. Moreover, the emission center 62A of the laser diode 60 and the end surface 32A of the waveguide 32 are extremely close to each other so that the bonding efficiency between the laser diode 60 and the optical waveguide 32 is allowed to be improved. As a result, low power consumption is achievable.
Moreover, in the embodiment, as described above, the light source unit 50 and the slider 11 (the bar 11Z) are bonded by the irradiation of the laser beam LB to the side surface 51B of the supporting member 51. The laser beam LB is applied to the supporting member 51 from the back side where the light source mounting surface 51C provided with the laser diode 60 is in a blind area. When the laser beam LB is applied from the front side of the light source unit 50, there is a possibility that error irradiation of the laser beam LB damages the laser diode 60 provided on the light source mounting surface 51C and the terminal electrodes 610 and 611 thereof. However, in the embodiment, such damage due to the error irradiation is avoidable. Consequently, in the embodiment, a thermally-assisted magnetic head device which provides high positional accuracy between the light source unit 50 and the magnetic read write head section 10, and is suitable for high density recording is achievable.
In the above-described embodiment, stress is applied between the supporting member 51 and the bar 11Z with use of the suction force of the suction nozzle 71. However, for example, as illustrated in
According to the procedures (
As illustrated in
After the position adjustment between the light source unit 50 and the bar 11Z on the XZ plane was completed, 30 pieces of magnetic head devices 4A were manufactured similarly to Example 1, except that the adhesive layer 58 was melted and bonded. As for them, similarly to Example 1, the offset amount (μm) from the reference position was measured. The results are also shown in Table 1.
As illustrated in Table 1, in Examples 1 and 2, in terms of all the offset amounts from reference position in the Z-axis direction, the X-axis direction, and on the XZ plane, it was confirmed from the comparison with Example 3 that the offset amount and the variation were small.
Note that in Examples 1 to 3, the optical waveguide 32 in which the lengths in the cross track direction, in the down track direction, and in the direction orthogonal to the ABS were 4 μm, 0.5 μm, and 50 μm, respectively, was used. In the case where the optical waveguide 32 having such an aspect ratio was used, the offset amount in the down track direction was dominant with respect to the bonding efficiency between the laser diode 60 and the optical waveguide 32.
Although the present invention has been described with the embodiment, the present invention is not limited to the embodiment described above, and various modifications may be made. For example, in the embodiment, although exemplified is a CPP-type GMR element as a read element, the read element is not limited thereto and may be a CIP (current in plane)—GMR element. In such a case, an insulating layer needs to be provided between an MR element and a lower shield layer, and between the MR element and an upper shield layer, and a pair of leads for supplying a sense current to the MR element needs to be inserted into the insulating layer. Alternatively, a TMR (tunneling magnetoresistance) element with a tunnel junction film may be used as a read element.
In addition, in the thermally-assisted magnetic recording head according to the invention, the configurations (shapes, positional relationship, and the like) of the waveguide, the plasmon generator, the magnetic pole, and the like are not limited to those described in the above-described embodiment, and any thermally-assisted magnetic recording head having other configuration may be available.
The correspondence relationship between the reference numerals and the components of the embodiment is collectively illustrated here. 1 . . . housing, 2 . . . magnetic disk, 3 . . . head arm assembly (HAA), 4 . . . head gimbals assembly (HGA), 4A . . . magnetic head device, 4B . . . suspension, 5 . . . arm, 6 . . . driver, 7 . . . fixed shaft, 8 . . . bearing, 9 . . . spindle motor, 10 . . . magnetic read write head section, 11 . . . slider, 11A . . . element forming surface, 11B . . . back surface, 11S . . . air bearing surface (ABS), 12 . . . element forming layer, 13 . . . insulating layer, 14 . . . read head section, 16 . . . write head section, 17 . . . clad, 21 . . . lower shield layer, 22 . . . MR element, 23 . . . upper shield layer, 24, 25, 27, 38, 39, 42 . . . insulating layer, 28 . . . lower yoke layer, 29 . . . leading shield, 30, 36, 37 . . . connecting layer, 31L, 31U, 33A, 33B . . . clad, 32, 72 . . . waveguide, 34 . . . plasmon generator, C34 . . . mid-portion, W34 . . . wing portion, 34A to 34C . . . first to third portions, 34G . . . pointed edge, 34L . . . lower layer, 34U . . . upper layer, 341 . . . surface plasmon exciting surface, 344 . . . edge, 35, 75 . . . magnetic pole, 351 . . . first layer, 352 . . . second layer, 40A, 40B . . . connecting section, 41 . . . coil, 43 . . . upper yoke layer, 45 . . . laser light, 46 . . . evanescent light, 47 . . . surface plasmon, 48, 49 . . . edge plasmon, 50 . . . light source unit, 51 . . . supporting member, 51A . . . bonding surface, 51B . . . side surface, 51C . . . light source mounting surface, 58 . . . solder layer, 60 . . . laser diode, 61 . . . lower electrode, 62 . . . active layer, 63 . . . upper electrode, 64 . . . reflective layer, 65 . . . n-type semiconductor layer, 66 . . . p-type semiconductor layer, 70 . . . alignment apparatus, 71 . . . suction nozzle, 72 . . . tray, 73 . . . photo-reception device, 74 . . . controller, 77 . . . laser beam, 78 . . . pressing member, NF . . . near-field light.
