Thin film magnetic head slider and electrostatic acutuator

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a thin film magnetic head slider used in a magnetic disk apparatus and a head slider including an electrostatic actuator for driving a head element thereof.

【0002】

[Conventional technology]

In recent years, with the miniaturization, high performance, and low price of magnetic disk devices, the development of high-performance and low-priced thin-film magnetic heads has been desired. As a method satisfying this requirement, a horizontal head (planar head) in which the thin film pattern film forming surface is parallel to the floating upper surface has been proposed. The reason is that the horizontal head can easily realize a stable low levitation head because it is easy to form a levitation rail having a specific shape, and it is easy to realize a low price because it is easy to reduce the number of machined parts. It depends on things.

【0003】

An example of a conventional horizontal magnetic head slider is shown below. IEEE TRANSACTIONS ON MAGNETICS, vol.25, p.3190, 1989, "A New Thin Film Head Generation", JP Lazzari and P. Deroux-Dauphin. A dent is formed in the dent, and a thin plate magnetic head element is formed in the dent. Since the surface of the silicon substrate is a floating upper surface facing the recording medium, a through hole penetrating the silicon substrate is formed to pull out the terminal in order to take out the terminal of the head to the back surface of the slider. The outer shape of the slider is formed by machining.

【0004】

IEEE TRANSACTIONS ON MAGNETICS, vol.25, p.3686, 1989, "A New Approach to Making Thin Film Head-Slider Devices", Daniel W. Chapman. A thin film magnetic head element is formed on the substrate from the floating top surface side first, the insulating film is flattened, and then the glass substrate that has penetrated the through hole is bonded to form the slider main body portion. After that, the substrate is etched and removed, and then the outer shape of the slider is cut by machining.

【0005】

[Problems to be Solved by the Invention]

In both the above and the conventional examples, the outer shape of the slider is formed by machining as before, the assembly with the support spring is also performed individually as before, and the conductor is formed by forming a through hole penetrating the substrate. The process is complicated because processes such as embedding and bonding the glass substrate are required.

【0006】

Therefore, the present invention can be easily manufactured without the need for forming a through hole or using a glass substrate, and tracking of a thin film magnetic head element (tracking direction substantially perpendicular to the moving direction of the recording medium). By adding a micro-movement mechanism to the tape head element or a micro-movement mechanism in the direction of approaching / separating from the load / unload recording medium, more accurate positioning of the magnetic head element is realized and high recording density is realized. It is an object of the present invention to provide a thin film magnetic head slider for measuring the improvement of reliability.

【0007】

Another object of the present invention is to provide a head slider provided with an electrostatic actuator suitable as a drive mechanism for adding a tracking mechanism or a load / unload mechanism in the thin film magnetic head element as described above.

【0008】

[Means for solving problems]

According to the present invention, a thin film formed by forming a slider film body on the surface of a substrate or the surface of a sacrificial layer provided on the substrate and separating the substrate or the substrate and the sacrificial layer from the slider film body. The magnetic head slider is provided with a tracking mechanism in which a part of the slider film body is supported by a fixed portion of the slider film body so as to be movable in a tracking direction substantially perpendicular to the moving direction of the recording medium, and the tracking mechanism is movable. Provided is a thin film magnetic head slider characterized in that at least the facing magnetic poles of the thin film magnetic head element facing the recording medium are provided in the portion.

【0009】

Further, according to the present invention, a slider film body is formed on the surface of the substrate or the surface of the sacrificial layer provided on the substrate, and the substrate or the substrate and the sacrificial layer are separated from the slider film body. In the thin film magnetic head slider, a load / unload mechanism is provided in which a part of the slider film body is supported by a fixed portion of the slider film body so as to be movable in the load / unload direction approaching / separating from the recording medium. Provided is a thin film magnetic head slider, which is provided with, at least, a facing magnetic pole of a thin film magnetic head element facing a recording medium in a movable portion of the load / unload mechanism.

【0010】

As described above, according to the present invention, in addition to the mechanism for tracking the entire support spring, only the element portion can be tracked with high accuracy, so that the track density of the recording medium can be improved. Further, since only the element portion can be lowered in levitation, the line recording density can be improved without impairing the reliability. Furthermore, according to the present invention, a fixed portion having a plurality of teeth parallel to each other, a movable portion having a plurality of teeth parallel to these teeth, and the movable portion moved in the tooth width direction with respect to the fixed portion. Movable to the point where the electrostatic attraction force in the tooth width direction generated by applying a voltage between the teeth of the support spring part that supports the fixed part and the movable part and the compound force of the support spring are balanced. Provided is a head slider comprising an electrostatic actuator comprising a driving force generating portion for moving the portions.

【0011】

Since the electrostatic actuator of the present invention provides a force for moving the movable portion in the tooth width direction, an electrostatic actuator having higher force generation efficiency than the conventional electrostatic actuator becomes possible.

【0012】

BEST MODE FOR CARRYING OUT THE INVENTION

1 (a) to 1 (c) show the first embodiment of the thin film magnetic head slider of the present invention. FIG. 1 (a) is a perspective view of the slider 10 mounted on the support spring 30 as viewed from the floating top side, and FIG. 1 (b) shows the slider 10 itself before being mounted on the support spring 30 on the back side (floating top surface). It is a perspective view seen from the opposite side), and FIG. 1 (c) is a diagram showing a cross section at line BB'of FIG. 1 (a).

【0013】

The floating top surface side of the slider 10 facing the recording medium (not shown) is SiO₂, Al₂O₃A part of the floating surface layer 11 made of the above and the like projects toward the medium, and forms two floating rails 15 extending from the inflow end 13 to the outflow end 14 with respect to the medium moving in the direction of arrow A. Further, a central rail 17 is formed on the inflow end 13 side between these two levitation rails 15. The main body 12 and the terminal pad portion 18 (FIG. 1 (b)) of the slider 10 formed on the back surface of the floating surface layer 11 are formed by plating a metal such as Ni.

【0014】

The element drive mechanism unit 20 (tracking mechanism in this embodiment) is formed in a part of the floating surface layer 11 at a position between the two floating rails 15 and between the terminal pad portion 18 and the outflow end 14. Has been done. That is, the element portion drive mechanism portion 20 is not formed with the plating (metal such as Ni) of the main body portion 12 of the slider 10. The length from the inflow end 13 to the outflow end 14 of the slider 10 is, for example, 0.5 to 0.8 mm, the width is 0.3 to 0.6 mm, and the thickness is 0.04 to 0.06 mm.

【0015】

The element unit drive mechanism unit, that is, the tracking mechanism unit 20 in the first embodiment utilizes electrostatic attraction as shown in the cross-sectional view of FIG. 1 (c), and the mover extends from the fixed portion. It consists of two parallel springs 21 (only one is shown) and an element mounting part 22 supported on the tip side of them. The parallel spring 21 of the mover and the stator 23 side facing the parallel spring 21 are made of a metal such as Ni or Cu. Alternatively, the mover and the stator have metal electrodes at opposite portions, and tracking is performed by applying a voltage between the stator electrode 23 and the mover electrode 21 to generate an attractive force. Is.

【0016】

In the mover, only the head element 24 or the magnetic pole tip 24a of the element is projected toward the medium (not shown), and the drive electrode portions 21 and 23 are installed so as to be separated from the medium. This is because the drive unit does not affect the levitation force of the slider 10, so that the voltage between the electrodes 21 and 23 does not attract dust around the head element 24. Further, although not shown in the figure, the floating upper surface side end portion of the outer peripheral surface of the slider 10 prevents collision with the medium when the posture changes due to rolling or pitching of the slider 10, or when colliding with the medium. It is desirable to perform R chamfering to prevent damage to the surface.

【0017】

There are two or four terminal pad parts 18 in the center of the back of the slider 10 that are connected to the terminal connection part (not shown) of the head suspension 30, one set is for the head element and one set is the tracking mechanism. For. When the MR element is also used as the lead head element, one set or two terminals may be used. FIGS. 2 (a) and 2 (b) show a modified example of the tracking mechanism 20. In the modified example of FIG. 2 (a), the stator electrode portion 23 shown in FIG. 1 (c) has a curved surface on the surface facing the movable electrode 21, and the parallel spring 21 of the mover is the fixed electrode portion 23. The amount of displacement is increased by deforming along the curved surface of. Further, in the modified example of FIG. 2B, the mover 21 and the stator 23 are composed of comb tooth electrodes 21a and 23a parallel to each other, and an attractive force is generated in a direction parallel to the length direction of these comb teeth. This is an example of tracking by letting.

【0018】

3 (a) and 3 (b) are the second embodiment of the thin film magnetic head slider of the present invention in which the tracking drive mechanism 20 is incorporated in one of the levitation rails 15 itself. By incorporating the drive unit 20 into the rail 15 itself as in the present embodiment, it is possible to further expand the arrangement area of the terminal pad 18 or further reduce the size of the slider. In this embodiment, any of the structures shown in FIGS. 1 (c), 2 (a), and 2 (c) can be adopted as the structure of the tracking drive mechanism 20. However, as described above, the electrodes 21 and 23 are formed slightly inside (on the side of the main body 12) from the surface of the levitation rail 15 so as to be separated from the medium (not shown), and dust is adsorbed by the voltage between the electrodes and the medium. It is desirable to have a structure that prevents discharge and the like.

【0019】

FIGS. 4 (a) and 4 (b) show the thin film magnetic head slider (third embodiment) of the present invention having a load / unload mechanism. The position where the load / unload mechanism 20A is provided may be between the levitation rails 15 as in the first embodiment, or may be incorporated in the levitation rail 15 itself as in the second embodiment. In this embodiment, the spring portion 21 of the mover is formed above the floating upper surface layer 11 of the slider with a slight interval in the levitation height direction, and the head element mounting portion 22 is formed at the tip of the spring portion 21. Is forming. By applying a voltage between the fixed side electrode 23 on the floating surface layer 11 side and the movable side electrode 21, the mover 21 is attracted to the floating surface layer side 11 side, so that the head element 24 is used as a medium (not shown). ), Or bring it into contact. The voltage applied in this mechanism may be started immediately after the start of rotation of the recording medium and stopped immediately before the medium is stopped, or may be energized in conjunction with the operation of the head element 24. You may start and stop.

【0020】

In the embodiments shown in FIGS. 1 to 4, a center rail is provided in the center of the slider 10 on the inflow end 13 side, and both side rails are provided on both sides near the outflow end, and a levitation force generating portion is provided at each point of a substantially triangular shape. When formed, the tracking mechanism 20 or load / unload mechanism 20A should be provided inside this triangle. The reason is that since there are three levitation force generating parts, even if the slider itself is deformed by the residual stress generated in each layer when forming the slider body and the levitation surface layer, it is not easily affected by the levitation amount fluctuation, and these 3 This is because a stable levitation amount can be secured by arranging the drive mechanism and the head element inside the triangle whose apex is a point.

【0021】

FIGS. 5 (a) and 5 (b) explain the principle of the electrostatic actuator that can be adopted as the drive mechanism in the present invention in comparison with the conventional example. One of the two facing comb teeth is the fixed portion 31, and the other is the movable portion 32. By applying a voltage between the two comb teeth, the movable portion 32 is moved by a small distance with respect to the fixed portion 31. Such an electrostatic actuator is, for example, Si that serves as an insulating layer on a silicon substrate with a thermal oxide film.₃N₄A film, a PSG (phosphosilicate glass) film as a sacrificial layer, and a 2 μm polysilicon film as a comb-shaped electrode are formed, and the polysilicon is formed into a desired shape by plasma etching, and finally the sacrificial layer is wet-enched. It removes and opens the movable part 32.

【0022】

In the conventional electrostatic actuator shown in FIG. 5 (a), the tooth on the movable part 32 side is placed at an intermediate position between the adjacent tooth on the fixed part 31 side and the tooth, and a voltage is applied between the two facing comb-shaped electrodes. The electrostatic actuator according to the present invention shown in FIG. 5 (b) is intermediate between adjacent teeth on the fixed portion 31 side, whereas the force is generated in the direction in which the meshing length of the teeth is shortened. The tooth on the movable portion 32 side is arranged at a position deviated from the position, and a force in the direction perpendicular to the tooth surface is generated. The difference between the conventional electrostatic actuator and the actuator according to the present invention will be described.

【0023】

In the conventional actuator, the tooth on the movable portion 32 side is arranged at an intermediate position between the adjacent tooth on the fixed portion 31 side and the tooth, and a force in the horizontal direction (X direction) in the drawing is generated. The magnitude of the force Fx is g for the gap between the tooth of the fixed part 31 and the tooth of the moving part 32, t for the tooth thickness, V for the applied voltage, and ε for the permittivity in vacuum.₀Then, the force in the X direction is Fx = V²ε₀It becomes t / g.

【0024】

On the other hand, in the electrostatic actuator according to the present invention, the gap between the tooth on the fixed portion 31 side and the tooth on the movable portion 32 side is a narrow gap g.₁And wide void g₂There is g₁Y direction (perpendicular to the tooth surface) force and g generated in₂The difference in force generated in the Y direction is the available force. Its size is Fy = (1/2) V²ε₀tL (1 / g₁²-1 / g₂²). g₁= g and 1 / g₂²<< 1 / g₁²Then, Fy / Fx L / 2g. When L> 2g, the electrostatic actuator according to the present invention can obtain a larger force. For example, if a gap of g = 1 μm and a tooth of L = 200 μm are formed, 100 times the force of the conventional electrostatic actuator can be obtained. Where g₂The force generated by is g₁Because it works in the direction of canceling the force generated in g₂Is g₁It is better to make it larger than the above, but if it is made too large, it will not be possible to provide many teeth in a limited size, so g₂/ g₁Has an optimal value for. g₁, g₂Generated force (Fy) and g when L is sufficiently larger than w₂/ g₁The relationship between is shown in Fig. 6. Since the number of teeth can only be an integer value, the graph will not be smooth if L is not large enough, but even in that case it is approximately 2 <g.₂/ g₁The force is maximum near <3. Practically 1.5 <g₂/ g₁<5 or 1.2 <g₂/ g₁It is better to use in the range of <10.

【0025】

FIG. 7 shows an embodiment of the electrostatic actuator of the present invention. The outer frame portion is a fixing portion 31 main body formed of Ni plating, and is fixed on a substrate (not shown). On the inner wall of the fixed portion 31 main body, teeth 31a parallel to each other at regular intervals are provided at regular intervals toward the inner circumference by Ni plating at the same time as the fixed portion 31 main body. These teeth 31a may be fixed on the substrate or may be provided with a gap (not shown) between the teeth 31a and the substrate. The central part inside the frame of the fixed part 31 is the movable part 32 main body formed by Ni plating at the same time as the fixed part 31 main body, and there is a gap (not shown) between the fixed part 31 and the fixed part 31. On the other hand, it is provided so that it can move relative to each other. Further, the movable portion 32 main body is provided with a plurality of teeth 32a at positions deviated from the center of adjacent teeth 31a provided on the fixed portion 31 so as to be parallel to the center. In the figure, columns 33 fixed to the substrate are formed above and below the movable portion 32, and the movable portion 32 can be moved only in the vertical direction in the drawing between the column 33 and the main body of the movable portion 32. A support spring 34 is provided. Lead wires 35 and 36 for connecting to terminals (not shown) are formed by Ni plating from the lower right and lower columns of the fixed portion 31.

【0026】

When a voltage is applied between the two conductors 35 and 36, the movable part 32 is sucked upward by the electrostatic attraction acting between the teeth 31a of the fixed part 31 and the teeth 32a of the movable part 32, and the support spring 34 Move to a position that balances the restoring force. Since the attractive force is proportional to the square of the potential difference, it moves in the same direction regardless of the polarity. However, in order not to affect the driven object (thin film magnetic head in the present invention) placed on the movable portion 32 by the driving noise, it is better to use the movable portion 32 grounded.

【0027】

In addition, in order to prevent the teeth 31a of the fixed portion 31 and the teeth 32a of the movable portion 32 from coming into contact with each other and causing a short circuit when an excessive voltage input is applied, the gap between the movable portion 32 and the movable portion 32 is shortened in a part of the support column 33. A short-circuited part is provided to serve as a stopper 37. The stopper 37, that is, the support column 33 has the same potential (grounding) as the movable portion 32, and there is no problem even if the stopper 37 comes into contact with the movable portion 32.

【0028】

Next, the method of manufacturing the electrostatic actuator of the present invention will be described with reference to FIGS. 8 and 9. These figures show the AA cross section in FIG. First, in FIG. (a) Thermal oxide film T-SiO on both sides₂Use a (100) Si substrate with. (b) Only the part forming the movable part 32 main body, the tooth 32a of the movable part 32, the tooth 31a of the fixed part 31 and the support spring 34 is a thermal oxide film T- on the substrate surface by ion milling or the like using a mask. SiO₂To remove. (c) An Al film is formed as a sacrificial layer on the surface of the substrate by vapor deposition or sputtering. (d) Thermal oxide film T-SiO₂The other partial Al sacrificial layer is removed by ion milling or the like, leaving only the portion from which the above has been removed. In this case, a slight gap is formed at the boundary between the Al sacrificial layer and the thermal oxide film. (e) Ni is formed on the entire surface as a base layer for plating by vapor deposition or sputtering. This base layer also penetrates into the gap.

【0029】

Next, in FIG. (a) Apply photoresist and pattern a hidden mold for forming the fixed portion 31, the movable portion 32, the support spring 34, the stopper 37, the support column 33, the lead wires 35, 36, etc. in FIG. 7 by Ni plating. (b) Ni is filled in the part without photoresist by Ni plating. (c) Remove the photoresist with a solvent. (d) By ion milling the entire surface, the underlying layer of the part not covered with Ni is removed. Of course, this step may be performed after patterning a protective photoresist (not shown) having the same shape on the plated Ni instead of full-scale ion milling. (e) By removing Al in the sacrificial layer with KOH solution, the movable part 32 is separated from the substrate and can move relative to each other. The moving part 32 is a thermal oxide film T-SiO₂Is removed, so the Si of the substrate is also melted, the KOH liquid easily penetrates, and the etching time is shortened.

【0030】

FIG. 10 shows another embodiment of the electrostatic actuator of the present invention. This embodiment differs from the embodiment of FIG. 7 in that the first tooth 31a of the fixing portion 31 and the second tooth 31b of the fixing portion 31 are provided on both sides of the tooth 32a of the movable portion 32 at equal intervals. It is a point. The insulating layer 38 shown in the figure electrically insulates the first tooth 31a and the second tooth 32b of the fixing portion 31 from each other, and different voltages can be applied. When the movable part 32 is electrically grounded and a voltage is applied to the first tooth 31a of the fixed part 31, the movable part 32 moves upward in the figure, and when a voltage is applied to the second tooth 31b of the fixed part 31, the movable part 32 Moves to the bottom of the figure. Due to the structure of this embodiment, the movable portion 32 can be moved upward and downward in the drawing, and the stroke is doubled as compared with the embodiment of FIG.

【0031】

Next, an example of applying a voltage to the first tooth 31a and the second tooth 31b of the stator 31 in the embodiment of FIG. 10 is shown in FIGS. 11 (a) to 11 (c). The direction of the force F is positive in the upward direction in the figure. (a) is a positive voltage V on the first tooth 31a when generating an upward force₁Negative voltage V on the second tooth 31b when applying a downward force₂Is an example of applying. (b) is a positive voltage V on the first tooth 31a when generating an upward force₁Positive voltage V on the second tooth 31b when applying a downward force₂Is applied. In (c), an offset voltage of 1/2 of the maximum voltage is applied to the first and second teeth 31a and 31b of the fixed portion 31, and the voltages V are opposite to each other.₁, V₂This is an example of superimposing and driving. V₁= V₀+ ΔV, V₂= V₀Expressed as -ΔV, FyV₁²-V₂²= 4V₀It becomes ΔV, and the force becomes proportional to ΔV, which makes it easier to control. The advantages of such a voltage application method are that it can be driven by only one power source and that the movable part can be driven in a state of being electrically grounded.

【0032】

As a preferred application example of the electrostatic actuator of the present invention, it is preferable to incorporate it as a driving unit of the above-mentioned tracking mechanism or load / unload mechanism in the head slider of a magnetic disk device. An example of such a head slider is shown in FIG. The slider 10 forms a horizontal thin-film magnetic head element 24, a floating surface layer 11, and a slider main body 12 by a series of processes and bonds them to the head suspension 30. In the magnetic disk device, the head suspension equipped with the head slider 10 is seekd and positioned by a voice coil motor, and in addition, a minute actuator (tracking mechanism in this embodiment) is mounted in the head slider to form a thin film. If the magnetic head element 24 is controlled in a high band, the positioning accuracy is further increased and the recording density can be increased. In the present invention, in order to reduce machining and reduce manufacturing costs, as will be described later, a horizontal head (also known as a planar head) 24 and a floating surface layer (SiO) are placed on a substrate via a sacrificial layer.₂) 11, is formed, the slider body 12 is formed by Ni plating, and then the sacrificial layer is removed to separate the slider portion 10 from the substrate. Further, the head slider 10 has a drive mechanism portion 20 of an electrostatic actuator that minutely drives the element portion 24 in the tracking direction.

【0033】

FIG. 13 shows the cross-sectional structure of the head slider 10. A sacrificial layer 41 that matches the shape of the floating surface is formed on the substrate 40 with Al, and a horizontal head element 24 is formed on the sacrificial layer 41.₂Is formed. This surface is a surface that serves as a sliding surface or an air-lubricated surface with a recording medium (not shown). In the figure, the layer 42 shown by the black line is a conductor pattern layer (Au) connecting each part of the head element and the electrostatic actuator and a terminal, and an insulating layer (SiO).₂), And the plating base layer (Ni). On top of that, the movable part 43, the fixed part 44, the support spring part (reference numeral 34 in FIG. 7) and the like of the electrostatic actuator are formed by Ni plating at the same time as the slider body 12 and the terminal 18. After this, plating may be added to increase the rigidity of only the slider main body portion excluding the actuator movable portion 43. Then, the Au bonding layer 45 is formed and patterned on the uppermost surface, bonded to the head suspension 30 as shown in FIG. 12, and the sacrificial layer 41 is dissolved with a KOH solution to separate the head slider 10 from the substrate 40.

【0034】

While the reproduction signal of the magnetic disk device is generally in the mV range, the drive voltage of the electrostatic actuator is several tens of V, and there is a concern that the drive of the actuator may affect the reproduction signal. However, in the present invention, the head element The movable portion 43 on which the 24 is mounted can be used by being grounded as described above, and the signal line is arranged from the head element 24 to the terminal 18 through a conductor pattern via an insulating layer below the movable portion 43. , It can be performed along the support spring 34 (FIGS. 7 and 10) connecting the actuator movable portion 43 and the fixed portion 44. Since the support spring 34 is also grounded, the signal line is shielded and a structure that is less susceptible to noise can be adopted.

【0035】

14 to 17 show an example in which an electrostatic actuator acting in both the tracking direction and the load / unload direction is incorporated in the head slider, and all of them are enlarged in the thickness direction. FIG. 14 is a perspective view of the head slider as seen from the floating top surface side, FIG. 15 is a fracture view of the electrostatic actuator portion incorporated inside the head slider, and FIGS. 16 and 17 are arrows A of FIG. 14, respectively.

【0036】

In these figures, 10 is the head slider and 11 is the floating surface layer (SiO) facing the medium.₂), 12 is the slider body (Ni), 15 is the rails on both sides (pressure generation pad), 17 is the center rail (pressure generation pad), 18 is the terminal, 51 is the fixed part, 52 is the movable part where the head element is provided, 53 Is a strut, 54 is a support spring portion that supports the movable portion 52, 55 is an insulating layer, 56 is an electrode, 57 is a protrusion provided on both side rails 15 on the medium side, and 58 is a surface lubrication layer (DLC).

【0037】

In this embodiment, the movable portion 52 is arranged inside a triangle composed of three pressure generating pads 15 and 17, and can move in the lateral direction X (tracking direction) with respect to the medium moving direction A with respect to the fixed portion 51. At the same time, it is supported by the support spring portion 54 so that it can move in the vertical direction Z (load / unload direction). The fixed portion 51 and the movable portion 52 have a plurality of parallel teeth 51a and 52a as in the embodiment of FIG. 7, and the movable portion teeth 52a are arranged so as to be offset from the center of two adjacent teeth 51a of the fixed portion. By applying a voltage (the movable part 52 is grounded) between the two, the movable part 52 moves in the X direction with respect to the fixed part 51 to a position where the electrostatic attraction force and the restoring force of the support spring part 54 are balanced. ..

【0038】

Further, the movable portion 52 opposes the support spring portion 54 by the electrostatic attraction force acting on the movable portion 52 by applying a voltage to the electrode 56 provided on the fixed portion facing the flat portion of the movable portion. It also moves slightly in the direction. Therefore, the support spring portion 54 supports the movable portion 52 so as to be movable in the Z direction. In the embodiment shown in FIG. 16, the protrusion 57 itself is made of a surface lubricant (DLC) to improve the lubricity between the head slider 10 and the medium. Further, in the embodiment of FIG. 17, the protrusion 57 itself is the floating surface layer 11 (SiO).₂), And the entire floating surface layer 11 including the protrusions 57 is covered with the surface lubricating layer 58 (DLC).

【0039】

In this embodiment, as shown in FIG. 14, the shape of the slider body and the obtuse angle portion are included, and the shape is substantially a polygonal prism shape. This is to reduce the weight by removing functionally unnecessary parts on both sides of the central pressure generating pad from the rectangular parallelepiped, and to reduce the probability of collision with the medium due to the rolling and pitching operations of the head slider. Further, by performing R chamfering on the outer circumference of the slider and the outer circumference of the pressure generating pad, damage to the medium can be minimized even if a collision with the medium should occur. C chamfering has the same effect instead of R chamfering.

【0040】

Since the head slider of the present invention does not require machining and is manufactured by a process mainly composed of photolithography, it is possible to deal with such a fine shape without increasing the machining man-hours and cost. This embodiment is an example in which a tracking actuator, a levitation direction drive actuator, and a REIT / write common head (inductive head) are mounted. The two electrostatic actuators require a total of three terminals with the moving part as a common potential (ground), and the head requires two terminals. In this embodiment, the movable part of the actuator has the same potential as the slider body, the slider body is used as one terminal, and each of the four terminals shown is connected to the conductor pattern on the head suspension.

【0041】

FIG. 18 shows an embodiment of a head slider in which a piezoelectric material is used for the drive unit. A mechanism 20 for minutely driving the head is provided in a part of the slider. The head drive unit 20 is attached in a beam shape so as to support the head unit 24 attached to the tip (head mounting portion 22). A piezoelectric thin film such as ZnO or PZT is laminated on the beam, and the head moves due to the minute displacement of the piezoelectric thin film.

【0042】

The head drive unit 20 is also not exposed on the floating upper surface and is located on the upper surface side of the floating upper surface. The magnetic pole portion 24 of the head 24 is exposed only on a part of the floating upper surface, and the medium surface (not shown) is read and written there. The drive unit 20 for moving the head will be described. As described above, the piezoelectric element 24 is laminated in a thin film on the element mounting portion 22 of the beam portion that supports the head.

【0043】

FIG. 18 (d) shows an enlarged cross-sectional view of the beam of the drive unit 20, where 61 is the sacrificial layer (Al) which is removed in the subsequent process as described above, 62 is the carbon film, and 63 is the head wiring. , 64 is the shield, 65 is the piezoelectric lower electrode, 66 is the material of the piezoelectric thin film ZnO, 67 is SiO₂Layer, 68 is the piezoelectric upper electrode, 69 is the upper protective layer (SiO)₂).

【0044】

The piezoelectric upper electrode 68 is divided into two parts (68a, 68b) from the center as shown in the figure. When the piezoelectric lower electrode 65 is on the ground side, a reverse phase voltage is applied to one electrode 68a and the other electrode 68b. As a result, minute displacements of opposite phases occur with respect to the left and right sides of the beam. As a result, the head 24 is slightly displaced in the direction of the arrow in FIG. 18 (a). PZT can also be used as the piezoelectric thin film 66, but in the case of this embodiment, a ZnO film is used. The advantage of ZnO film is (1) A stable film with orientation can be formed by sputtering or the like.

【0045】

(2) A film is formed at a lower temperature than PZT. (PZT 600 ° C, ZnO 200 ° C or less) (3) Piezoelectricity is determined by the orientation of the film and does not require polarization treatment like PZT. (4) This is a well-proven film used in commercially available SAW filters. There is. The drawbacks are as follows.

【0046】

(1) Piezoelectric constant is lower than PZT. (2) Easily soluble in acids and alkalis. As a countermeasure against the drawback of the ZnO thin film, which is easily dissolved in acids and alkalis, in order to make the ZnO thin film difficult to dissolve during etching of the sacrificial layer (Al) 61, ZnO is shown in FIG. 18 (d). Film 66 is used as an electrode material 65,68 or SiO₂It is better to have a structure covered with 67 mag.

【0047】

FIG. 19 shows another embodiment of the drive unit using the piezoelectric material. In this embodiment, the ZnO piezoelectric thin film 66 is applied from above and below the outside of the electrodes 65 and 68.₂It has a structure covered with a film 69 such as. Further, if the piezoelectric thin film 66 has a minute bore, there is a risk of dielectric breakdown between the upper and lower electrodes 65 and 68. Therefore, as shown in the embodiment of FIG. 18 (a) or this embodiment, the upper surface of the piezoelectric thin film 66 Alternatively, SiO on the lower surface inside the electrodes 65 and 68, which is thinner than the piezoelectric film 66.₂It is desirable to provide a dielectric breakdown prevention film 67 such as.

【0048】

The narrower the width of the beam of the drive unit formed of the piezoelectric film 66, the larger the amount of displacement. That is, the thinner the ZnO thin film 66 is, the larger the displacement amount is because the electric field strength per supply voltage is increased. However, due to the risk of dielectric breakdown, the maximum supply voltage will be ± 50V. The width, film thickness, and other dimensions of the beam have a great relationship with the resonance frequency of the beam portion. Generally, the resonance frequency is reduced by making the beam portion thinner or by making the film thickness thinner. Therefore, each dimension is restricted by the balance between the above-mentioned displacement amount and the resonance frequency.

【0049】

As a method of minimizing the decrease in the amount of displacement and ensuring the rigidity of the beam in the ascending direction, it is conceivable to provide a columnar structure in the central portion of the beam width. Such an embodiment is shown in FIG. By having the columnar structure 70 of Ni only in the central part of the beam width, the ratio of hindering the movement in the tracking (arrow X in FIG. 20) direction is relatively small, but the movement in the ascent (arrow Z in FIG. 20) direction is relatively small. Rigidity is significantly improved.

【0050】

In the drive unit using the piezoelectric film shown in FIGS. 18 to 20, the head 24 is minutely moved in the tracking (X) direction as described above by applying a voltage of opposite phase to the upper electrodes 68a and 68b divided into two. However, by applying a voltage of the same phase to the upper electrodes 68a and 68b divided into two, a minute movement in the levitation (Z) direction can also be performed.

【0051】

FIG. 21 shows the case of minute displacement in the tracking (X) direction, and FIG. 22 shows the operating principle for minute displacement in the levitation (Z) direction. In the case of FIG. 22, by making the film thicknesses of the upper layer 71 and the lower layer 72 sandwiching the ZnO thin film 66 different, the neutral axis does not coincide with the center of the piezoelectric film and shifts upward in the cross section including the piezoelectric film. When the piezoelectric film is expanded and contracted with this configuration, the beam is bent in the Z direction, and a desired displacement in the Z direction (load / unload direction) is obtained. Even if the film thicknesses of the upper layer 71 and the lower layer 72 are the same, the effect of shifting the neutral axis upward can be expected due to the presence of the columnar structure as shown in FIG. In actual driving, it is preferable to be able to perform both tracking correction and load / unload gap correction. In addition, in FIG. 21 and FIG. 22, for convenience of explanation, the amount of displacement of the beam is remarkably exaggerated.

【0052】

[Effect of the invention]

According to the present invention, the structure and manufacturing process of the head slider are simple, and further, a mechanism for tracking the head element or a load / unload mechanism can be incorporated, so that a high-performance and low-cost thin-film magnetic head slider can be incorporated. Can be provided. It is also possible to increase the density of the recording medium.

【0053】

Further, since the electrostatic actuator of the present invention provides a force for moving the movable portion in the tooth width direction, an electrostatic actuator having a higher force generation efficiency than the conventional electrostatic actuator becomes possible. By mounting this on the head slider, the head slider and electrostatic actuator are integrated while maintaining manufacturing consistency, and there is no need for machining, and the head can be positioned with submicron accuracy over a stroke of about 1 μm. It is possible to obtain a precise head slider that can be performed.

[Simple explanation of drawings]

[Figure 1]

1 (a) to 1 (c) show the first embodiment of the thin film magnetic head slider of the present invention, (a) is a perspective view seen from the floating upper surface side, and (b) is seen from the back surface side. The perspective view, (c), shows the tracking drive mechanism unit of the head element in the BB'cross section.

[Figure 2]

2 (a) and 2 (b) show each modification of the tracking drive mechanism unit shown in FIG. 1 (c).

[Fig. 3]

3 (a) and 3 (b) show a second embodiment of the thin film magnetic head slider of the present invention, (a) is a perspective view seen from the floating top side, and (b) is a view from the back side. It is a perspective view.

[Fig. 4]

4 (a) and 4 (b) are a cross-sectional view and a longitudinal cross-sectional view corresponding to FIG. 1 (c) of the load / unload drive mechanism unit.

[Fig. 5]

5 (a) and 5 (b) are diagrams showing a conventional example of an electrostatic actuator and the principle of the present invention.

[Fig. 6]

FIG. 6 is a graph showing the operation of the electrostatic actuator of the present invention.

[Fig. 7]

FIG. 7 is a plan view showing an embodiment of the electrostatic actuator of the present invention.

[Fig. 8]

8 (a) to 8 (e) are explanatory views showing the first half of the process of forming the electrostatic actuator of the present invention in the order of the steps.

[Fig. 9]

9 (a) to 9 (e) are explanatory views showing the latter half of the process of forming the electrostatic actuator of the present invention following the process of FIG. 8 in step order.

[Fig. 10]

FIG. 10 is a plan view showing another embodiment of the electrostatic actuator of the present invention.

[Fig. 11]

11 (a) to 11 (c) show an example of applying electricity to the electrostatic actuator according to the embodiment of FIG.

[Fig. 12]

FIG. 12 is a perspective view of a head slider incorporating an electrostatic actuator.

[Fig. 13]

FIG. 13 is a cross-sectional view of a head slider incorporating an electrostatic actuator.

[Fig. 14]

FIG. 14 is a perspective view of a head slider incorporating an electrostatic actuator that moves minutely in the tracking direction and the load / unload direction.

[Fig. 15]

FIG. 15 is a cross-sectional view of the actuator drive unit of the head slider of FIG.

[Fig. 16]

FIG. 16 is an arrow A (a) of the head slider of FIG.

[Fig. 17]

FIG. 17 is an arrow A (b) of the head slider of FIG.

[Fig. 18]

18 (a) to 18 (d) show an example of a head slider using a piezoelectric material for the drive unit, (a) is a perspective view of the head slider viewed from the floating top side, (b) is a rear view, ( c) is an AA cross-sectional view of (a), and (d) is an enlarged cross-sectional view of the drive unit.

[Fig. 19]

FIG. 19 is an enlarged cross-sectional view corresponding to FIG. 18D, showing another embodiment of the drive unit using the piezoelectric material.

[Fig. 20]

FIG. 20 shows yet another embodiment of the drive unit using the piezoelectric material.

[Fig. 21]

21A and 21B are views for explaining the operation when the driving unit is driven in the tracking direction using a piezoelectric material, where FIG. 21A is a top view and FIG. 21B is a cross-sectional view of a beam.

[Fig. 22]

FIG. 22 is a diagram for explaining the operation when the driving unit is driven in the load / unload direction by using the piezoelectric material, (a) is a cross-sectional view in the beam side surface direction, and (b) is a cross-sectional view of the beam.

[Explanation of symbols]

10 ... slider 11 ... Floating top layer 12 ... Slider body 13 ... Inflow end 14 ... outflow end 15 ... Rails on both sides 17 ... Central rail 20 ... Tracking mechanism 21 ... Parallel spring (movable side electrode) 21a ... Movable tooth (movable side electrode) 22 ... Head mounting part 23 ... Fixed part (fixed side electrode) 23a ... Fixed tooth (fixed side electrode) 24 ... Head element 30 ... Head suspension 31 ... Fixed part 31a ... Fixed tooth (fixed side electrode) 32 ... moving parts 32a ... Movable tooth (movable side electrode) 33 ... props 34 ... Support spring 35,36 ... Lead 37 ... Stopper 40 ... board 41 ... Al (sacrificial layer) 42 ... Plating base, insulation layer, conductor pattern layer 43 ... moving parts 44 ... Fixed part (12 ... Slider body) 45 ... Au (bonding layer) 51 ... Fixed part 51a ... Fixed tooth 52 ... Moving parts 52a ... Movable teeth 53 ... prop 54 ... Support spring 55 ... Insulation layer 56 ... Electrodes 57 ... protrusion 58 ... Surface Lubrication Layer (DLC) 61 ... Sacrificial layer (Al) 62 ... Carbon film 63 ... Head wiring 64 ... Shield 65 ... Lower electrode 66 ... Piezoelectric membrane (ZnO) 67 ... SiO₂68 ... Upper electrode 69 ... Upper protective layer (SiO)₂) 70 ... Columnar structure (Ni plating)