JP5969876B2 - Thermally assisted magnetic head inspection method and thermally assisted magnetic head inspection apparatus - Google Patents

Description

  The present invention relates to a thermally assisted magnetic head inspection method and a thermally assisted magnetic head inspection apparatus for inspecting a thermally assisted magnetic head, and particularly to generation of near-field light generated by a thermally assisted magnetic head that cannot be inspected by a technique such as an optical microscope. The present invention relates to a thermally assisted magnetic head inspection method and a thermally assisted magnetic head inspection apparatus capable of inspecting a state.

  As an apparatus for inspecting a magnetic head nondestructively, a method using an optical microscope, a method using a scanning electron microscope (SEM), a method using an atomic force microscope (AFM), a magnetic force There is a method using a microscope (Magnetic Force Microscope: MFM).

  Each of the above-described methods has advantages and disadvantages, but in that the magnetic field generated by the magnetic head for writing to the hard disk can be inspected nondestructively, a method using a magnetic force microscope (MFM) is another type of observation means. It is superior to the method using.

  Using this magnetic force microscope (MFM), the effective track width of the light track is measured in the state of a row bar in which a plurality of magnetic head elements before the magnetic head elements formed on the wafer are individually separated. This is described, for example, in JP 2010-175534 A (Patent Document 1). That is, in Patent Document 1, a magnetic field is generated by applying a current to a magnetic head circuit pattern of a rover as a sample, and the magnetic probe attached to the cantilever is brought close to the generated magnetic field to displace the probe of the cantilever. It is described that a magnetic field generated by a sample is measured two-dimensionally by detecting the quantity by two-dimensionally scanning a cantilever.

  In the conventional magnetic head inspection, a recording signal (excitation signal) is input from a bonding pad to a thin film magnetic head in a magnetic head rover state, and a magnetic field generated from a recording head (element) included in the thin film magnetic head is observed. , By moving the scan at a position corresponding to the flying height of the magnetic head and directly observing with a magnetic force microscope (MFM), scanning Hall probe microscope (SHPM) or scanning magnetoresistive microscope (SMRM) As a method for measuring the generated magnetic field shape instead of the physical shape of the head (element) and enabling the magnetic effective track width inspection to be performed nondestructively, Patent Document 2 discloses an HGA state using a spin stand. Or, the effective track width that could only be inspected in the pseudo HGA state can be measured in the rover state by using a magnetic force microscope. Rukoto is described in JP 2009-230845 (Patent Document 2).

  On the other hand, as a new technology for next-generation hard disks that are required to dramatically increase the capacity, a magnetic recording method using heat assist has been attracting attention and is being developed by various companies. To increase the density and capacity of hard disks, it is necessary to reduce the track width, which is said to be almost the limit of conventional magnetic heads. However, it is necessary to use a heat-assisted magnetic head that uses near-field light as a heat source. As a result, a track width of about 20 nm can be realized.

  This heat-assisted magnetic recording head has a cross-sectional shape in which the width in the direction perpendicular to the polarization direction of incident light traveling through the waveguide gradually decreases toward the apex where near-field light is generated, and the progress of the incident light Near-field light is generated using a conductive structure that has a shape that gradually becomes smaller or stepwise toward the apex where near-field light is generated in the direction. Japanese Patent Application Laid-Open No. 2011-146097 (Patent) discloses a configuration in which a waveguide is disposed beside a conductive structure and near-field light is generated through surface plasmons generated on the side surface of the conductive structure. Reference 3).

  However, the effective intensity distribution and size of near-field light, which is an important factor for the track width, cannot be measured by surface shape inspection using an optical microscope or SEM. is there.

This near-field light will be briefly described below. When light is applied to a particle with a diameter much smaller than the wavelength of the light, a localized electromagnetic field is generated around the particle. This is called near-field light.
Both scattered light and near-field light are electromagnetic fields generated by electric dipoles induced inside the sphere when incident light hits the sphere. However, while the scattered light travels far away, the energy of the near-field light concentrates along the spherical shape and cannot be observed at a position away from the sphere. Moreover, it is said that the near-field light is distributed only from the particle at a distance that is about the diameter of the particle. Therefore, even if a photodetector is installed at a distant location, it is impossible to know the presence of near-field light that has clung to particles.

  Therefore, in order to detect the near-field light, the near-field light can be detected by placing another particle near the particle emitting the near-field light and scattering the near-field light. That is, since the scattered near-field light can propagate far away, a part of it is observed by the photodetector. Here, the shape of the particles emitting near-field light can be known by scanning the particles as the scattering means around the particles emitting near-field light and observing the scattered near-field light.

  As a technique for detecting the near-field light, a scanning probe is brought close to the near-field light, and the near-field light can be detected by scattering the near-field light. Patent Document 4 discloses "Optical Microscopy, NSOM; Near-field Scanning Optical Microscopy, NOM; Near-field Optical Microscopy").

JP 2010-175534 A JP 2009-230845 A JP 2011-146097 A JP 2006-38774 A

  Patent Document 1 describes that a two-dimensional distribution of a magnetic field formed by individual magnetic head elements formed on a row bar of a magnetic head is measured by two-dimensionally scanning a cantilever having a probe. The configuration and method for measuring the near-field light and magnetic field generated by the thermally-assisted magnetic head are not mentioned.

  In conventional magnetic recording, since the size of the magnetic field generating portion of the head is the track width, the track width of the head can be inspected by measuring the magnetic field according to Patent Document 1, but the size of the generated near-field light is small. It becomes difficult to inspect the heat assist head having the track width.

  Also, in the magnetic head inspection device that inspects the magnetic execution track width by measuring the generated magnetic field shape in the state of the rover described in Patent Document 2, the near-field light and the magnetic field generated by the thermally-assisted magnetic head are detected. There is no mention of a configuration for measuring and its method.

  On the other hand, Patent Document 3 describes a structure of a thermally assisted magnetic recording head and a magnetic recording apparatus incorporating the head. However, the inspection of near-field light and magnetic field generated by the thermally assisted magnetic recording head is described. Is not touched.

  Further, Patent Document 4 describes that near-field light and other light are separately detected in the vicinity of the near-field light emitting element, but the near-field light generated by the thermally-assisted magnetic recording head is described. There is no mention of examining the magnetic field.

  The object of the present invention is to switch the observation optical system and the near-field light detection system with good reproducibility by rotating or up-and-down mechanism when changing the work or when measuring another near-field light emitting part arranged in the work. Thus, it is possible to provide an inspection machine in which the alignment of the workpiece, the confirmation of the position of the feeding probe, and the reading of the product number can be observed and adjusted on a monitor, and the positional relationship of the near-field light emitting unit is optimized.

  Furthermore, an object of the present invention is to enable high-precision measurement of a magnetic field generated by a heat-assisted magnetic head and a near-field light generation region with the influence of heat generation in the near-field light generation region reduced as much as possible. A thermally assisted magnetic head element inspection method and a thermally assisted magnetic head element inspection apparatus are provided.

  In order to solve the above-described problems, in the present invention, a thermally assisted magnetic head inspection apparatus includes a thermally assisted magnetic head element and an XY table that is movable in the XY plane, and a magnetic film is formed on the tip. A scanning probe microscope means comprising a cantilever having a probe, and supplying an alternating current to a terminal formed on a thermally assisted magnetic head element mounted on the XY table of the scanning probe microscope means, A probe unit for applying a driving current or a driving voltage to the near-field light emitting unit formed on the thermally assisted magnetic head element, and an imaging means for capturing the thermal assisted magnetic head element mounted on the XY table in a field of view. And when the probe is in a generation region of near-field light generated from a near-field light emitting part formed in the thermally-assisted magnetic head element Application of either means by mechanically switching between the scattered light detecting means having a light detector for detecting scattered light generated from the probe, and the arrangement of the imaging means and the scattered light detecting means. An optical system switching means that enables the image pickup means to recognize the image picked up by the image pickup means, and the scattered light detection means to the appropriate position for detecting the scattered light, the near-field light emitting unit and the An alignment unit that adjusts a relative position with respect to the scattered light detection unit; and an AC current is supplied to the terminal in a state in which laser incidence is stopped from the probe unit to the near-field light emitting unit. By scanning the surface with the probe of the cantilever while generating a magnetic field on the surface, the supply of the output signal output from the scanning probe microscope means and the alternating current to the terminal is stopped. In this state, the surface of the thermally-assisted magnetic head element is scanned with the probe of the cantilever while a laser is incident on the near-field light emitting unit from the probe unit to generate near-field light from the near-field light emitting unit. And signal processing means for inspecting the thermally-assisted magnetic head element using the output signal output from the scattered light detection means.

In order to solve the above-described problems, in the present invention, a thermally assisted magnetic head inspection method includes a cantilever having a probe having a magnetic film formed on the surface at the tip, an XY table movable in an XY plane, A heat-assisted magnetic head element is mounted on the XY table of the scanning probe microscope equipped with the thermal-assisted magnetic head element in the field of view, picked up by an image pickup means, and the image picked up by the image pickup means is subjected to recognition processing The XY table adjusts the relative position between the near-field light emitting part formed in the thermally-assisted magnetic head element and the scattered light detecting means to an appropriate position for the scattered light detecting means to detect the scattered light, An alternating current is supplied to a terminal formed on the thermally-assisted magnetic head element mounted on the thermal-assisted magnetic head element to generate a magnetic field in the thermally-assisted magnetic head element, and the thermally-assisted magnetic head With the magnetic field generated in the element, the surface of the thermally-assisted magnetic head element is scanned with the probe of the cantilever of the scanning probe microscope to obtain the distribution of the generated magnetic field, and the arrangement of the imaging means and the scattering By mechanically switching the arrangement of the light detection means, the scattered light detection means is applied, and a laser is incident on the near-field light emitting portion formed in the thermally-assisted magnetic head element mounted on the XY table. A near-field light is generated from the near-field light emitter, and the near-field light is generated from the near-field light emitter, and the surface of the thermally-assisted magnetic head element is scanned with a cantilever probe of the scanning probe microscope. The scattered light generated from the probe in the near-field light generation region is scanned and collected by the scattered light detection means, and the near-field light emission region and the light are detected from the detected scattered light. Distribution was determined, so as to determine the quality of the thermally-assisted magnetic head element based on the light emitting region and information of the distribution of near-field light obtained above and the distribution of the calculated magnetic field.

  According to the present invention, since the position of the workpiece can be confirmed by the observation optical system after the workpiece is transferred to the measurement stage, the alignment of the workpiece, the position of the feeding probe, and the reading of the serial number can be easily observed on the monitor. The time for bringing the particles as the scattering means closer to the near-field light can be greatly shortened.

  In addition, by switching between the observation optical system and the near-field light detection system, when the workpiece is changed or when measuring another near-field light emitting unit arranged in the workpiece, alignment is performed to bring the detector closer to the detector. The positional relationship of the field light is optimized, and the scattered near-field light can be detected efficiently.

It is a block diagram which shows the structure of the outline | summary of the test | inspection part of the thermally assisted magnetic head element in embodiment of this invention. It is a side view of the mounting part of the mounting part for positioning the Y-bar of the test | inspection part of the thermally-assisted magnetic head element which concerns on embodiment of this invention, and the row bar mounted in the Y stage. It is a side view of the probe unit which concerns on embodiment of this invention. It is a perspective view of the row bar of the inspection object concerning the embodiment of the present invention. It is a top view of the magnetic head element which shows the state which made the front-end | tip part of the probe contact the electrode of the thermally assisted magnetic head element in embodiment of this invention. It is a block diagram which shows the structure of the near field light detection optical system in the embodiment of this invention, an observation optical system, and a detection field light detection control part. It is a figure explaining the detection principle in the test | inspection part of the thermally assisted magnetic head element in embodiment of this invention, and is a side view of the cross section of a cantilever and a rover which shows the state which is measuring the magnetic field which a thermally assisted magnetic head element produces | generates . FIG. 5 is a diagram for explaining the detection principle in the inspection unit of the thermally-assisted magnetic head element in the embodiment of the present invention, and shows a cross section of a cantilever, a detector, and a rover showing a state in which near-field light generated by the thermally-assisted magnetic head element is measured FIG. FIG. 3 is a plan view of an inspection area showing a relationship between an inspection area in the embodiment of the present invention and a scanning direction of a probe, a magnetic field generation area, and a near-field light generation area inside the inspection area. It is a top view of the inspection area which shows the relation between the inspection area in other embodiments of the present invention, the scanning direction of the probe within the inspection area, the magnetic field generation area, and the near-field light generation area. It is a figure which shows the example of a monitor screen of the heat-assisted magnetic head element part of the test object imaged with the CCD camera of the observation optical system. It is a figure which shows the example which plotted the intensity distribution of the near field light generated from the near field light generation part on the coordinate axis of the scanning direction of a probe. It is a block diagram of control PC of the magnetic head element test | inspection apparatus in embodiment of this invention. It is a flowchart which shows the procedure which test | inspects a heat-assisted magnetic head element using the magnetic head element test | inspection apparatus in embodiment of this invention. It is a flowchart which shows the procedure of the process of the test | inspection in embodiment of this invention.

  The present invention provides a thermally assisted magnetic device in a state of a row bar before the thermally assisted magnetic head elements are individually separated or in a state of a head assembly in which the thermally assisted magnetic head elements are individually separated from the row bar and assembled to a gimbal. The present invention relates to a magnetic head element inspection method and apparatus for inspecting a light emission state of near-field light generated by a head element and a magnetic field distribution using an apparatus to which a scanning probe microscope is applied.

  In the following, a mode for carrying out the present invention (embodiment) will be described with reference to the drawings in the case of inspecting in the state of the row bar before the thermally-assisted magnetic head elements are individually separated.

  FIG. 1A shows the configuration of an apparatus for inspecting a thermally assisted magnetic head element according to this embodiment. The heat-assisted magnetic head inspection apparatus 100 according to the present embodiment is a process of processing a wafer on which a large number of thin film magnetic head elements are formed and cutting out a slider alone (thin film magnetic head chip) in the magnetic head element manufacturing process. It is possible to measure the intensity distribution of near-field light generated by the thermally-assisted magnetic head element in the state of the row bar 40 (a block in which a plurality of head sliders are arranged). Usually, the row bar 40 cut out from a wafer on which a large number of thin-film magnetic head elements are formed as an elongated block body of about 3 cm to 10 cm has a configuration in which about 40 to 90 head sliders (thin-film magnetic head elements) are arranged. It has become. The row bar 40 has a built-in laser element serving as a light emitting source.

  The magnetic head element inspection apparatus 100 according to the present embodiment is based on a scanning probe microscope. The magnetic head element inspection apparatus 100 includes an inspection stage 101 and an X stage 106 that is mounted on the inspection stage 101 and driven by a piezo element (not shown) that can move the row bar 40 by a minute distance in the X and Y directions. Y stage 105 is provided.

  The row bar 40 has one side surface in the long axis direction abutted against a reference surface 1141 provided on the stepped portion 1142 of the positioning portion 114 for positioning the row bar 40 provided on the upper surface of the Y stage 105. Positioned in the direction. As shown in FIG. 1B, the row bar 40 is placed at a predetermined position in the Z direction and the X direction by contacting the side surface (reference surface) 1141 of the stepped portion 1142. The side surface (reference surface 1141) of the stepped portion 1142 is in contact with the rear side surface of the row bar 40 (the surface opposite to the surface on which the magnetic head element electrodes 41 and 42 of the thermally-assisted magnetic head element are formed). 40 positioning is performed.

  As shown in FIG. 1A, the magnetic head element inspection apparatus 100 is provided with a camera 103 for measuring the amount of positional deviation of the row bar 40 above the Y stage 105. The Z stage 104 is fixed to the column 1011 of the inspection stage 101, and moves the cantilever 10 in the Z direction. The X stage 106, the Y stage 105, and the Z stage 104 of the inspection stage 101 are each composed of a piezo stage that is driven by a piezo element (not shown).

  The magnetic head element inspection apparatus 100 further includes a cantilever 10, an excitation unit 122, a near-field light detection optical system 115, a displacement detection unit 130, a probe unit 140, an oscillator 102, a piezo driver 107, a differential amplifier 111, a DC converter 112, A feedback controller 113 and a control unit 30 are provided. The control unit 30 includes a near-field light detection control system 530 that controls the near-field light detection optical system 115.

  The cantilever 10 is vibrated with a predetermined amplitude at a predetermined frequency by a vibration unit 122 fixed to the Z stage 104 by controlling the position in the Z direction by the Z stage 104.

  The displacement detector 130 detects the vibration state of the cantilever 10. The displacement detection unit 130 includes a laser light source 109 and a displacement sensor 110, applies a laser emitted from the laser light source 109 to the cantilever 10, and detects light regularly reflected by the cantilever 10 with the displacement sensor 110. A signal output from the displacement sensor 110 is sent to the control unit 30 via the differential amplifier 111, the DC converter 112, and the feedback controller 113 for processing.

  The probe unit 140 receives the signal 301 from the control unit 30, applies power and a laser to the inspection target element of the row bar 40 placed on the placement unit 114, and applies a magnetic field and near-field light to the inspection target element. Is generated.

  The near-field light detection optical system 115 detects near-field light generated from the inspection target element of the row bar 40 and outputs a detection signal 302 to the control unit 30.

  The piezo driver 107 oscillates a piezo drive signal in response to the signal from the oscillator 102 and drives the X stage 106, Y stage 105, and Z stage 104.

  In the configuration described above, the control unit 30 controls the X stage 106, the Y stage 105, and the Z stage 104 via the piezo driver 107 based on the image of the row bar 40 captured by the camera 103, so that the row bar 40 is in a predetermined position. Adjust the positioning so that When the positioning adjustment of the row bar 40 is completed, the probe unit 140 is driven based on a command from the control unit 30, and the tip portion of the probe 141 contacts the magnetic head element electrodes 41 and 42 formed on the row bar 40.

  2A, the probe unit 140 has a configuration in which a probe card (or substrate) 141 and a probe 142 attached to the probe card 141 are fixed to the probe base 143. The support plate 144 supports the inspection stage 101. On the other hand, the row bar 40 is a square bar-like substrate on which a large number of magnetic head elements 501 are formed as shown in the perspective view of FIG. 2B, and the magnetic bars formed inside the row bar 40 of the magnetic head elements as shown in FIG. 2C. By applying an alternating current 1431 with the head element electrodes 41 and 42 in contact with the tip portions 1421 and 1422 of the probe 142, a magnetic field is generated from the write magnetic field generation unit 502 (see FIG. 4A) of the write circuit unit 43. Occur. By setting the frequency of the alternating current applied to the row bar 40 to a frequency different from the resonance frequency of the cantilever 10, the vibration of the cantilever 10 is not affected. Although not shown in the drawing, the row bar 40 also has a connection pad for connecting to the laser driver 531.

  In this state, the X stage 106 and the Y stage 105 are driven to scan the scanning area 401 including the writing magnetic field generation unit 502 with the cantilever 10, and the change in the amplitude of the cantilever 10 is detected with the displacement detection unit 130. By processing the received signal by the control unit 30, the distribution of the magnetic field generated from the write magnetic field generation unit 502 of the row bar 40 can be measured at high speed, and the write execution track width can be measured. The row bar 40 is sucked and held by a suction means (not shown) provided on the placement unit 114.

  The probe card 141 is configured to be movable in the Y direction by the drive unit 143, and the tip portions 1421 and 1422 of the probe 142 and a large number of magnetic head element electrodes 41 and 42 formed on the row bar 40 are sequentially in contact with each other. Drive to move away.

  3, the detailed configuration of the near-field light detection optical system 115 will be described in relation to the near-field light detection control system 530 inside the control unit 30 and the cantilever 10. The positional relationship between the row bar 40 (501) and cantilever 10 shown in FIG. 3 and the near-field light detection optical system 115 is opposite to that shown in FIG. 1A.

  In the cantilever 10, the tip 5 of the probe 4 formed in the vicinity of the tip of the cantilever 10 is positioned at a height corresponding to the head flying height Hf from the surface of the heat-assisted magnetic head element 501 formed on the row bar 40. Thus, the positioning is performed by the Z stage 104. On the surface of the probe 4, there are a thin magnetic film 2 (for example, Co, Ni, Fe, NiFe, CoFe, NiCo, etc.) and a noble metal (for example, gold, silver or platinum) or a fine particle or thin film 3 of an alloy containing a noble metal. Is formed.

  A write magnetic field generation unit 502 and a near-field light generation unit 504 are formed in the heat-assisted magnetic head element unit 501.

  The near-field light detection optical system 115 includes an objective lens 511, an imaging lens 514, and a photodetector (photomal) 523, and the light imaged by the imaging lens 514 is immediately before the photodetector 523. And is detected by the photodetector 523. Each element of the near-field light detection optical system 115 is configured as a near-field light detection optical system unit 210 fixed in a predetermined arrangement.

  The heat-assisted magnetic head element unit 501 formed on the row bar 40 of the measurement unit, which is replaced on the same optical axis as the near-field light detection optical system unit 210 or on a predetermined parallel optical axis, and the cantilever 10 An observation optical system unit 220 that fits the distal end portion within the field of view includes an objective lens 515, a half mirror 512, an LED light source 513, an imaging lens 516, and a CCD camera 525 that detects an optical image formed by the imaging lens 516. It is configured as an integral structure.

  The near-field light detection optical system unit 210 and the observation optical system unit 220 are mechanically moved by an optical system switching mechanism 230 (for example, a stage movable in the vertical direction of the paper surface in FIG. 3 or in the direction perpendicular to the paper surface). It is switched with high accuracy by parallel movement or by rotational movement.

  Further, the near-field light detection control system 530 constituting a part of the control unit 30 generates a near-field light 505 from the near-field light generation unit 504 of the thermally-assisted magnetic head element unit 501, and is not shown in the drawing. A laser driver 531 that applies a pulse drive current or pulse drive voltage 5311 to the near-field light generator 504 via a waveguide, and a pulse modulator 532 that adjusts the oscillation frequency of the pulse drive current or pulse drive voltage 5311 oscillated from the laser driver 531. The control board 533 for controlling the laser driver 531 and the pulse modulator 532, the bias power source 534 for applying a bias voltage to the photodetector (Photomal) 523, and the signal detected by the photodetector 523 are synchronized with the vibration of the cantilever 10. Light detection detected by the lock-in amplifier 535 for extracting the signal and the lock-in amplifier 535 And an output signal and a control processing in response to an output signal from the CCD camera 525 PC536 from 523. The output from the control PC 536 is displayed on the monitor screen 31 of the control unit 30.

  In the configuration of the near-field light detection optical system 115 and the near-field light detection control system 530 as described above, pulse driving controlled by the pulse modulation signal from the pulse modulator 532 controlled by the control board 533 from the laser driver 531 is performed. A current or pulse drive voltage 5311 is applied to the near-field light generating unit 504 of the thermally-assisted magnetic head element unit 501 via a waveguide (not shown), and is brought close to the surface of the thermally-assisted magnetic head element unit 501 by a pulse laser. A field light 505 is generated.

  Although the near-field light 505 itself is generated only in a very limited region on the upper surface of the near-field light generating unit 504, the fine particles of the noble metal or the alloy containing the noble metal formed on the magnetic film 2 on the surface of the probe 4 of the cantilever 10 are used. Alternatively, when the thin film 3 enters the generation region of the near-field light 505, scattered light by the near-field light 505 is generated from the fine particles of the noble metal or the alloy containing the noble metal or the thin film 3. Of the generated scattered light, the scattered light incident on the objective lens 511 of the imaging lens system 510 forms a scattered light image on the surface of the probe 4 of the cantilever 10 on the imaging surface of the imaging lens 514. The pinhole 521 is installed at a place where a scattered light image on the surface of the probe 4 is formed on the imaging plane. Since the size of the probe 4 is sufficiently smaller than the size of the pinhole 521, the scattered light image on the surface of the probe 4 passes through the pinhole 521 and is detected by the photodetector 523. On the other hand, light that becomes noise from other than the surface of the probe 4 reaches a position deviated from the pinhole 521 on the imaging plane, cannot pass through the pinhole 521, and is blocked by the photodetector 523. With this configuration, the intensity of the scattered light generated on the surface of the probe 4 by the near-field light generated from the near-field light generating unit 504 of the thermally-assisted magnetic head element unit 501 is affected by the light that becomes noise. Can be detected by the photodetector 523.

  On the other hand, when the observation optical system unit 220 is positioned for observation of the measurement unit, the half mirror 512 out of the light emitted from the LED light source 513 with respect to the virtually assisted heat-assisted magnetic head element unit 551. The light reflected by the objective lens 515 passes through the objective lens 515 and illuminates the probe 4 of the cantilever 10 and the heat-assisted magnetic head element portion 501 (551). The image of the area irradiated with the illumination light is formed again on the exit side of the imaging lens 516 by the imaging lens system 520. By setting the detection surface of the CCD camera 525 so as to coincide with the imaging surface on the emission side of the imaging lens 516, the image of the probe 4 of the cantilever 10 and the heat-assisted magnetic head element unit 501 is converted into the CCD camera 525. The image is taken with.

  The imaging by the CCD camera 525 is performed before the inspection of the heat-assisted magnetic head element unit 501 is started, that is, in a state where the near-field light 505 is not generated from the near-field light generator 504.

  The image captured by the CCD camera 525 is subjected to image processing by taking a grayscale image obtained by A / D conversion into the control PC 536. As shown in the example of the monitor screen 31 in FIG. 6A, for example, the alignment line 601 preset on the screen matches the lower end line of the thermal assist magnetic head element portion 501 to be inspected, and the adjacent heat The boundary of the assist magnetic head element is recognized by edge detection or the like, and the field of view of the observation optical system is adjusted so as to coincide with the alignment lines 602 and 603 set in advance on the screen. The visual field is adjusted by driving the X stage 106, the Y stage 105, and the Z stage 104 in conjunction with the positioning positions of the observation optical system unit 220 and the near-field light detection optical system unit 210. Can be considered. Thereby, alignment of the optical system is performed so that the scattered light generated by the probe 4 of the cantilever 10 can be optimally captured.

  As shown in the example of the monitor screen 31 in FIG. 6A, the ID data such as the product number stamped on the heat-assisted magnetic head element unit 501 to be inspected is set by, for example, a recognition window 610 and character recognition processing. It is recognized and the result is recorded.

  In the state where the near-field light detection optical system 115 is set as described above, the probe 141 of the probe unit 140 is driven by the drive unit 143 under the control of the control unit 30, and the tip portions 1421 and 1422 of the probe 141 are driven. Are in contact with the magnetic head element electrodes 41 and 42 formed on the row bar 40, respectively. In addition, the waveguide from the laser driver 531 (not shown) and the near-field light generating unit 504 of the thermally-assisted magnetic head element 501 are connected.

  As a result, the signal 301 (AC current 1431 and pulse drive current or pulse drive voltage 5311) output from the control unit 30 can be supplied to the heat-assisted magnetic head element formed on the row bar 40. In this state, the heat-assisted magnetic head element 501 to be inspected of the row bar 40 that is sucked and held by a suction means (not shown) provided on the mounting portion 114 can generate a magnetic field from the write magnetic field generator 502, The light emitting unit 504 can emit near-field light.

  As shown in FIG. 4A, a cantilever 10 capable of measuring both the near-field light and the magnetic field is disposed at an opposing position above the row bar 40 placed on the Y stage 105 of the inspection stage 101. . The cantilever 10 is attached to a vibration unit 122 provided on the lower side of the Z stage 104. The excitation unit 122 is composed of a piezo element, an alternating voltage having a frequency near the mechanical resonance frequency is applied by an excitation voltage from the piezo driver 107, the cantilever 10 is vibrated, and the tip 4 of the probe 4 in the vertical direction ( (Z direction).

  As shown in FIGS. 4A and 4B, the probe 4 of the cantilever 10 in this embodiment is formed in a tetrahedral structure at the tip of the plate-like lever 1 of the cantilever 10. The lever 1 and the probe 4 are made of silicon (Si). A thin magnetic film 2 is formed on the front side of the lever 1 and the probe 4 (the side facing the near-field light detection optical system 115: the left side of FIGS. 4A and 4B), and a noble metal is formed on the surface of the magnetic film 2. Alternatively, fine particles or a thin film 3 of an alloy containing a noble metal is formed. Since the cantilever 10 includes the lever 1, the probe 4, the thin magnetic film 2, the noble metal particles or the thin film 3, both the near-field light and the magnetic field can be measured.

  That is, the thin magnetic film 2 formed on the surface of the probe 4 determines the sensitivity and resolution when measuring the magnetic field, and senses the magnetic field of the object to be measured when measuring the magnetic field 503 generated by the magnetic field generator 502. Further, the noble metal (for example, gold or silver) or the fine particle or thin film 3 of the alloy containing the noble metal formed on the surface of the probe 4 is fine when the probe 4 enters the generation region of the near-field light 506. Is amplified by the localized surface plasmon enhancement effect so that the amount of light can be detected by the near-field light detection optical system 115. However, the fine particles or the thin film 3 of the noble metal or the alloy containing the noble metal is not necessarily required. If the magnetic film 2 is sufficiently thin, when the near-field light 505 hits the magnetic film 2, the localized surface plasmon enhancing effect is obtained. The scattered light 506 generated from the surface of the probe 4 by the near-field light can be amplified to a light amount that can be detected by the near-field light detection optical system 115.

  As shown in FIG. 1A, the vibration in the Z direction of the probe 4 of the cantilever 10 is detected by a displacement detector 130 including a semiconductor laser element 109 and a displacement sensor 110 formed of a four-split optical detector element. The In this displacement detector 130, the laser emitted from the semiconductor laser element 109 is irradiated on the surface of the cantilever 10 opposite to the surface on which the probe 4 is formed, and the laser reflected by the cantilever 1 enters the displacement sensor 110. To do. The displacement sensor 110 is a four-divided sensor in which the light receiving surface is divided into four regions, and the laser incident on each of the divided light receiving surfaces of the displacement sensor 110 is photoelectrically converted and output as four electric signals. .

  Here, the displacement sensor 110 has a light receiving surface divided into four parts, and when the laser beam is irradiated from the semiconductor laser element 109 in a state where the cantilever 10 is not vibrated by the vibration unit 122, that is, in a stationary state. In addition, the reflection light from the cantilever 10 is installed at a position where it is equally incident on each of the four light receiving surfaces. The differential amplifier 111 performs predetermined arithmetic processing on the difference signal of the four electrical signals output from the displacement sensor 110 and outputs the result to the DC converter 112.

That is, the differential amplifier 111 outputs a displacement signal corresponding to the difference between the four electrical signals output from the displacement sensor 110 to the DC converter 112. Therefore, in a state where the cantilever 10 is not vibrated by the vibration unit 122, the output from the differential amplifier 111 becomes zero. The DC converter 112 is an RMS-DC converter (Root Mean) that converts a displacement signal output from the differential amplifier 111 into an effective DC signal.
It is composed of Squared value to Direct Current converter.

  The displacement signal output from the differential amplifier 111 is a signal corresponding to the displacement of the cantilever 10 and becomes an AC signal because the cantilever 10 vibrates during the inspection. A signal output from the DC converter 112 is output to the feedback controller 113. The feedback controller 113 outputs a signal output from the DC converter 112 to the control unit 30 as a signal for monitoring the current magnitude of the cantilever 10 and adjusts the magnitude of the excitation of the cantilever 10. A signal output from the DC converter 112 is output to the piezo driver 107 through the control unit 30 as a control signal for the Z stage 104. This signal is monitored by the control unit 30, and the piezo driver 107 controls the piezo element (not shown) that drives the Z stage 104 according to the value, so that the initial position of the cantilever 10 is determined before the measurement is started. I try to adjust it.

  In the present embodiment, the X-stage 106 and the Y-stage 105 are driven by the piezo driver 107 while the cantilever 10 is vibrated at a predetermined frequency by the vibration unit 122, whereby a thermally-assisted magnetic head as shown in FIG. 5A. The cantilever 10 scans the inspection area 401 of the element portion 501. This inspection region 401 is a region having one side of several hundred nm to several μm.

  When the X stage 106 is moved in this inspection area 401 while vibrating the cantilever 10 up and down, the probe 4 is scanned in the X direction along the dotted line 402 from the left side to the right side of the figure (thermal assist head element 501). Is moved in the + X direction in FIG. 4A), a magnetic field is generated from the write magnetic field generation unit 502 of the thermally-assisted magnetic head element unit 501, and the cantilever 10 is moved in MFM (Magnetic Force Microscope) mode. Drive to detect the generated magnetic field. During the inspection in the MFM mode, the laser output from the laser driver 531 to the near-field light emitting unit 504 is stopped.

  On the other hand, when the X stage 106 is scanned in the X direction along the dotted line 403 from the right side to the left side of the drawing (the thermal assist head element 501 is moved in the -X direction in FIG. 4B), the thermal assist magnetic head element The cantilever 10 is driven in an AFM (Atomic Force Microscope) mode without generating a magnetic field from the writing magnetic field generating unit 502 of the unit 501 to measure the uneven shape on the surface of the inspection region 401 and the laser driver 531. The near-field light emitting unit 504 outputs a pulse driving current or pulse-driving voltage to generate near-field light from the near-field light generating unit 504, and the near-field light detecting optical system 115 detects the near-field light.

  Near-field light is generated from the near-field light generator 504 by a pulse drive current or a pulse drive voltage 5311 oscillated from the laser driver 531. Here, the light emission efficiency of the near-field light in the near-field light generation unit 504 is about several percent with respect to the laser incident energy, and the rest is converted into thermal energy, and the near-field light generation unit 504 and its vicinity generate heat. become. When a heat-assisted magnetic head element is incorporated in a magnetic disk and data is written to the magnetic disk, the magnetic disk is rotating at a speed of several thousand rpm and is caught between the magnetic disk and the heat-assisted magnetic head element. The near-field light generating part of the heat-assisted magnetic head element is air-cooled by air, and the temperature rise is suppressed. However, since there is no air-cooling mechanism when inspecting a thermally assisted magnetic head element, the temperature of the near-field light generating unit is, for example, 50 W in the laser driver 531 when inspecting by generating near-field light. Is incident on the near-field light generating unit 504, the temperature of the near-field light generating unit 504 and its vicinity rises to about 200 to 300 ° C.

  In order to reduce the influence of this heat generation, in this embodiment, as described above, detection of near-field light (AFM mode detection) and magnetic field detection (MFM mode detection) generated in the heat-assisted magnetic head element unit 501 are performed. ) Are alternately performed, and the time for continuously generating near-field light is made as short as possible. In addition, the pulse laser generated by the pulse driving current or the pulse driving voltage applied to the near-field light generating unit 504 to generate the near-field light controls the laser driver 531 so that the duty is 25% or less, Heat generation from the near-field light generating unit 504 was suppressed.

  As described above, during the inspection, the MFM mode inspection and the AFM mode inspection are switched according to the X-direction scanning direction of the thermally-assisted magnetic head element unit 501 with respect to the cantilever 10, and near-field light emission is performed while the inspection is performed in the MFM mode. By stopping the application of the pulse driving current or the pulse driving voltage 5311 to the unit 504, it becomes possible to suppress the temperature rise of the heat-assisted magnetic head element unit 501 due to heat generation from the near-field light emitting unit 504, and heat Generation of damage in the assist magnetic head element portion 501 can be avoided.

  In the MFM mode and the AFM mode, the height of the probe 4 of the cantilever 10 with respect to the surface of the inspection region 401 of the thermally-assisted magnetic head element unit 501 is switched. That is, when inspecting in the AFM mode, the height of the probe 4 of the cantilever 10 with respect to the surface of the inspection area 401 of the thermally-assisted magnetic head element portion 501 corresponds to the head flying height Hf at the time of writing to the magnetic disk. Set to the height you want. On the other hand, in the MFM mode, the height of the probe 4 is set to be greater than Hf (the gap between the surface of the inspection region 401 and the tip of the probe 4 is increased). This height switching is performed by driving the Z stage 104 with a piezo driver 107.

  In the example shown in FIG. 5A, the adjacent dotted lines 402 and 403 are displayed so as to scan different positions in the Y direction, but the same positions in the Y direction, that is, the dotted lines 402 and 403 overlap. May be scanned. In that case, first, the thermally assisted magnetic head element portion 501 is moved along the dotted line 402 to perform the AFM mode inspection, and the thermally assisted magnetic head element portion 501 is moved in the reverse direction along the dotted line 403. Check the mode. Next, the AFM mode inspection and the MFM mode inspection are performed by moving the heat-assisted magnetic head element portion 501 by one pitch in the Y direction.

  Next, a method for detecting a magnetic field generated from the thermally-assisted magnetic head element unit 501 at the time of MFM mode inspection will be described.

  First, the Z stage 104 is controlled by the piezo driver 107 so that the probe 4 is at a height position (gap) with respect to the heat-assisted magnetic head element portion 501 at the time of MFM mode inspection. On the other hand, when an alternating current 1431 is applied in a state where the tip portions 1421 and 1422 of the probe 142 are in contact with the electrodes 41 and 42 formed on the row bar 40 by being driven by the drive unit 143 of the probe unit 140, the write circuit unit A write magnetic field 503 is generated from the 43 write magnetic field generator 502. At this time, the laser output from the laser driver 531 to the near-field light generator 504 is blocked. Next, in a state where the cantilever 10 is vibrated by the vibration unit 122, the X stage 106 on which the row bar 40 is placed is moved at a constant speed by a piezo element (not shown) controlled by a piezo driver 107. The probe 4 scans the inspection area 401 of the heat-assisted magnetic head element 501 in the direction (+ X direction) along the dotted line 402 in FIG. 5A.

  When the probe 4 of the cantilever 10 enters the write magnetic field 503 generated by the write magnetic field generator 502, the thin film magnetic body 2 formed on the surface of the probe 4 is magnetized, and the probe 4 receives magnetic force. As a result, the vibration state of the cantilever 10 changes. This change in vibration is detected by the displacement sensor 110 in FIG. 1A. That is, when the vibration state of the cantilever 10 changes, the incident position on the light receiving surface divided into four of the displacement sensor 110 of the laser emitted from the semiconductor laser element 109 and reflected by the cantilever 10 changes.

  By detecting the output of the displacement sensor 110 with the differential amplifier 111, it is possible to detect a change in the vibration state of the cantilever 10 according to the scanning position. By processing the detected signal by the control unit 30, it is possible to detect the intensity distribution of the write magnetic field 503 generated by the magnetic field generation unit 502 of the thermally-assisted magnetic head element unit 501. The quality of the write magnetic field generator 502 can be determined by comparing the detected write magnetic field intensity distribution with a preset reference value.

  After driving the X stage 106 and moving the probe 4 by the distance in the X direction of the inspection region 401, the driving of the X stage 106 is stopped to stop the inspection in the MFM mode, and the mode is switched to the AFM mode. The X stage 106 is moved in the reverse direction.

  Next, a method for detecting the state of generation of near-field light from the thermally-assisted magnetic head element unit 501 at the time of AFM mode inspection will be described. At the time of AFM mode inspection, while the cantilever 10 is vibrated by being driven by the vibration unit 122, the inspection region 401 is scanned in the −X direction along the dotted line 403 by the probe 4, and the cantilever 10 being scanned is scanned. Is detected by the displacement detector 130 to obtain information on the unevenness of the surface of the inspection region 401, and at the same time, scattered light generated from the probe 4 while scanning the upper surface of the near-field light generator 504 is approached. Detection is performed by the field light detection optical system 115. To perform the AFM mode inspection, first, the Z stage 104 is controlled by the piezo driver 107 so that the probe 4 is at a height position (gap) with respect to the heat-assisted magnetic head element unit 501 in the AFM mode. Next, the pulse drive current or pulse drive voltage 5311 output from the laser driver 531 is applied from the probe unit 140 to the near-field light generating unit 504 of the thermally-assisted magnetic head element unit 501.

  In this state, as shown in FIG. 4B, the cantilever 10 is vibrated in the vertical direction with respect to the surface (recording surface) 510 of the row bar 40 by the vibration unit 122, and the X stage 106 on which the row bar 40 is placed is fixed. Scan in the X direction at the speed of (2) in the direction opposite to the above-described MFM inspection (−X direction). A change in vibration of the cantilever 10 while scanning the X stage 106 is detected by the displacement sensor 110 of the displacement detector 130. On the other hand, when the probe 4 reaches the region where the near-field light 505 is generated by the near-field light generator 504 while scanning the X stage 106, the probe 4 enters the region where the near-field light 505 is generated. Scattered light 506 is generated from the surface of the existing portion. The scattered light generated on the surface of the probe 4 is localized by a noble metal (for example, gold or silver) formed on the magnetic film 2 on the surface of the probe 4 or an alloy-containing fine particle or thin film 3. Amplified by surface plasmon enhancement effect. Of the amplified scattered light, the scattered light incident on the near-field light detection optical system 115 disposed in the vicinity of the cantilever 10 is detected by the photodetector 523.

  After driving the X stage 106 and scanning with the probe 4 in the direction opposite to that in the MFM mode by the distance in the X direction of the inspection area 401, the driving of the X stage 106 is stopped and the inspection in the AFM mode is stopped. . Next, the Y stage 107 is driven and the inspection area 401 is moved by one pitch in the Y direction with respect to the probe 4, and the X stage 106 is driven in the same direction as in the previous MFM mode and the inspection area is moved by the probe 4. Scanning in the X direction of 401 is repeated, and the entire surface of the inspection region 401 is scanned with the probe 4.

  In this way, the entire surface of the inspection area 401 is scanned once by the probe 4, so that the magnetic field generation area generated from the magnetic field generation section 502 of the thermally assisted magnetic head element section 501 and the near field generated from the near field light generation section 504 are obtained. By detecting the scattered light from the probe 4 by light, the near-field light generation region can be detected.

  FIG. 7 shows the configuration of the control PC 536. The control PC 536 is realized by a general computer, the arithmetic unit 710 is a central processing unit, the storage unit 720 is an external storage device such as a hard disk device, and includes an input unit 730 such as a keyboard and a mouse, and an input / output interface 740. Is done. In FIG. 1A, the near field light detection control unit 530 is included in the control unit 30, but the control PC 536 in FIG. 7 includes the control function of each unit of the magnetic head element inspection apparatus 100. To do.

  The storage unit 720 includes a control parameter storage area 721 that stores in advance control parameters of each unit of the magnetic head element inspection apparatus 100, a control program storage area 722 that stores a control program executed by the calculation unit 536, and a thermal assist. A magnetic field intensity storage area 723 for recording the magnetic field intensity value detected by scanning the inspection area 401 of the magnetic head element 501 in association with the scanning coordinate value of the probe, and a near-field light generator 504 of the thermally assisted magnetic head element 501. A near-field light emission intensity storage area 724 for recording the near-field light emission intensity value detected by scanning the upper surface of the probe in association with the scanning coordinate value of the probe, the magnetic field intensity storage area 723, and the near-field light emission Magnetic field distribution, near-field light intensity distribution, near-field light generation area shape and position calculated based on data recorded in the intensity storage area 724 Which measurement results manufacturing number and association with and a measurement result storage region 725 for storing.

The computing unit 710 includes processing units that are realized by loading each control program stored in the control program storage area 722 into the memory of the computing unit and executing it.
The measurement scan control unit 711 performs probe unit 140, X, Y, Z stage, vibration unit 122, displacement detection unit 130, and near-field light detection optics for the inspection area 401 of the heat-assisted magnetic head element 501 to be measured. The system 115 is controlled to scan the entire surface or a required scanning region with a probe, and measure the magnetic field intensity and near-field light emission intensity.
The probe excitation control unit 712 vibrates the cantilever 10 at a predetermined frequency and with a predetermined amplitude, detects the vibration state of the cantilever 10 by the displacement detection unit 130, and the signal output from the displacement sensor 110 is differential. Input through the amplifier 111, the DC converter 112, and the feedback controller 113 to detect changes in the state of vibration.

The work alignment control unit 713 takes an image of a state in which a work (such as a rover or a head assembly attached to a gimbal) is mounted on the mounting unit 114 for positioning on the upper surface of the Y stage 105 by the mounting robot. The position deviation is confirmed, and the positioning of the workpiece to the initial inspection position is controlled.
The optical system alignment controller 714 outputs from the CCD camera 525 the position of the workpiece of the measuring unit (such as the heat-assisted magnetic head element formed on the rover, the head assembly mounted on the gimbal) by the observation optical system unit 220. Recognize from the image and adjust the X and Y stages so that the predetermined shape of the workpiece is aligned with the alignment line on the image, or positioning positions of the observation optical system unit 220 and the near-field light detection optical system unit 210 Drive in conjunction with to adjust. Thus, the optical system is aligned so that the scattered light generated by the probe 4 of the cantilever 10 can be captured optimally.
The product number recognition unit 715 recognizes ID data such as a product number stamped on the heat-assisted magnetic head element unit 501 to be inspected in the image of the observation optical system by setting a recognition window 610, for example, by character recognition processing. To do.

  The magnetic field intensity distribution detection unit 716 detects the output change of the displacement sensor 110 due to the magnetic force generated by the scanning of the probe 4 on the write magnetic field generation unit 502 in the processing of the measurement scan control unit 711. By detecting at, a change in the vibration state of the cantilever 10 corresponding to the scanning position is detected. The detected magnetic field intensity is recorded in the magnetic field intensity storage area 723 in association with the scanning coordinate value of the probe.

  The near-field light emission intensity detector 717 detects the scattered light from the probe 4 by the near-field light generated from the near-field light generator 504 by the photodetector 523 of the near-field light detection optical system 115 and detects the detected signal. The near-field light emission intensity is calculated from the output of the signal synchronized with the vibration of the cantilever 10 from the lock-in amplifier 535 and recorded in the near-field light emission intensity storage area 724 in association with the scanning coordinate value of the probe. .

Based on the data recorded in the magnetic field intensity storage area 723 and the near-field light emission intensity storage area 724, the measurement result calculation section 718 generates the distribution of the magnetic field intensity generated from the magnetic field generation section 502 and the near-field light generation section 504. The distribution of the intensity of the near-field light thus obtained is obtained. For example, the Gaussian distribution as shown in FIG. 6B is obtained as the intensity distribution of the near-field light. The probe scanning position coordinate 621 having the median value 620 by the statistical processing represents the X coordinate position of the near-field light generating unit 504. Further, if the distribution of the intensity of near-field light having the same X-coordinate value on each scanning line shifted in the Y direction is obtained, the Y-coordinate position of the near-field light generating unit 504 can be obtained in the same manner.
Similarly, the position of the magnetic field generator 502 can be obtained by statistical processing of the distribution of the magnetic field intensity generated from the magnetic field generator 502.

  Further, by comparing the magnetic field intensity distribution and the near-field light intensity distribution with preset reference data, the magnetic field generated from the magnetic field generation unit 502 and the state of near-field light emission from the near-field light generation unit 504 (magnetic field) Strength, magnetic field distribution, magnetic field generation region shape and position, near-field light intensity, near-field light distribution, near-field light generation region shape and position, and the like.

Further, the positional relationship between the write magnetic field (alternating magnetic field) 503 generated by the magnetic field generation unit 502 of the heat-assisted magnetic head element unit 501 and the thermal assist light (near-field light) 505 generated from the near-field light generation unit 504 is also measured. It becomes possible. Thereby, it is possible to inspect the intensity distribution of the write magnetic field and the near-field light of the thermally-assisted magnetic head element and measure the positional relationship between them at the earliest possible stage during the manufacturing process.
The above calculation results and determination results are recorded in the measurement result storage area 725 in association with the product number of the work (thermally assisted magnetic head element unit) recognized by the product number recognition unit 715.

FIG. 8 shows a flow of an inspection process by the heat-assisted magnetic head inspection apparatus 100 according to this embodiment.
In step S801, a workpiece (row bar 40) is taken out from the supply tray by a handling unit (not shown), conveyed onto the inspection stage 101, and pressed against the reference surface 1141 of the Y stage 105 in the Y stage. The row bar 40 is mounted on the stepped portion 1142 formed by the mounting unit 114 and the mounting unit 114. In synchronization therewith, the optical system switching mechanism 230 is driven to set the observation optical system unit 220 to a position where the heat-assisted magnetic head element 501 to be inspected is observed.

  In step S802, the camera 103 images the row bar 40 to obtain the position information of the row bar 40. Based on the obtained position information, the X stage 106 or the Y stage 105 is driven to adjust the position of the row bar 40. Do.

  In step S803, the X and Y stages are adjusted so that the predetermined shape of the workpiece is aligned with the alignment line on the image from the image obtained by imaging the heat-assisted magnetic head element 501 to be inspected by the CCD camera 525 of the observation optical system unit 220. The optical system is aligned by driving / adjusting the positioning positions of the observation optical system unit 220 and the near-field light detection optical system unit 210 in conjunction with each other.

  In step S804, the optical system switching mechanism 230 is driven to switch the near-field light detection optical system unit 210 to the measurement position.

The measurement process flow of step S805 is shown in FIG.
In the measurement process, first, the drive unit 143 of the probe unit 140 is operated to advance the probe 142, and the tip portions 1421 and 1422 of the probe 142 are formed on the row bar 40. The magnetic head element of the thermally-assisted magnetic head element unit 501 formed on the row bar 40 The electrodes 41 and 42 are brought into contact with each other. (S901)
Next, the Z stage is driven and the cantilever 10 moves to the inspection area 401 on the recording surface 510 of the thermally-assisted magnetic head element portion 501 to a position for inspection in the MFM mode. (S902)
Next, a signal 301 is supplied to the heat-assisted magnetic head element unit 501 to generate a write magnetic field (AC magnetic field) 503 from the magnetic field generator 502 (S903).

  Next, the cantilever 10 is inspected in the MFM mode while the piezo driver 107 drives a piezo element (not shown) while the cantilever 10 is vibrated by the vibration unit 122 and the X stage 106 is moved at a constant speed in the X direction. The area 401 is scanned (S904). When the probe 4 of the cantilever 10 reaches the end of the inspection area 401 in the X direction, the driving of the X stage 106 is stopped (S905). Next, the Z stage is driven to adjust the position of the cantilever 10 so that the distance between the recording surface 510 of the thermally-assisted magnetic head element portion 501 and the probe 4 becomes the distance in the AFM mode (S906), and the probe unit. The near-field light generating unit 504 is applied with a pulse driving current or a pulse driving voltage 5311 from 140 to generate near-field light near the near-field light generating unit 504 inside the inspection region 401 (S907).

  Next, a piezoelectric element (not shown) is driven by a piezo driver 107 while the cantilever 10 is vibrated by the vibration unit 122 to move the X stage 106 at a constant speed in the −X direction, and the cantilever 10 is moved in the AFM mode. The inspection area 401 is scanned (S908). When the probe 4 of the cantilever 10 reaches the end of the inspection region 401 opposite to the X direction, the driving of the X stage 106 is stopped (S909).

  Next, it is checked whether or not all the predetermined scanning lines on the inspection area 401 have been inspected (S910). If all the predetermined scanning lines have not been inspected (NO in S910), the piezo driver 107 performs piezo. The element (not shown) is driven to move the Y stage 105 to the Y coordinate of the next scanning line (S911), and S901 to S910 are repeatedly executed.

  By repeatedly executing the processing from S901 to S911, the distribution of the write magnetic field 503 generated from the magnetic field generation unit 502 of the thermally-assisted magnetic head element 501 and the generation region of the near-field light 505 generated from the near-field light emission unit 504 are performed. Can be detected by scanning a predetermined scanning line on the inspection region 401 once with the probe 4.

Next, returning to step S806 in FIG. 8, it is determined whether or not the next heat-assisted magnetic head element 501 that has not been inspected still remains on the work (rover 40). If it remains, the process proceeds to step S807. The next heat-assisted magnetic head element 501 is moved to the measurement position.
In step S808, the optical system switching mechanism 230 is driven to switch the observation optical system unit 220 from the near-field light detection optical system unit 210 to the measurement position, and the process proceeds to step S803.

  If it is determined in step S806 that the next heat-assisted magnetic head element 501 that has not yet been inspected on the work (rover 40) does not remain, the process proceeds to step S809 and is inspected by a handling unit (not shown). The work (row bar 40) placed on the placement unit 114 on the stage 101 is unloaded and stored in the collection tray.

  Next, in step S810, it is checked whether or not there is an uninspected work (rover 40) in the supply tray. If there is, the process proceeds to step S811, and the next work (rover 40) is selected. Proceeding to step S801, if there is no uninspected work (rover 40), the inspection is terminated.

  According to this embodiment, the write magnetic field (alternating magnetic field) and the heat assist light (near field light) generated from the heat assist magnetic head element 501 formed on the row bar 40 by the inspection unit 100 of the heat assist magnetic head can be converted into the cantilever 10. Thus, detection can be performed by scanning the entire surface of the inspection region or a predetermined number of scanning lines only once, and inspection can be performed upstream of the manufacturing process and in a relatively short time.

  In the above embodiment, the example of inspecting the thermally assisted magnetic head element 501 formed on the row bar 40 has been described. However, even in the state of the head assembly in which the thermally assisted magnetic head element 501 is assembled to a gimbal (not shown), The inspection can be performed in the same manner. In this case, the mounting portion 114 may be changed to a shape suitable for mounting the head assembly.

  Next, another embodiment different from the above embodiment will be described. The difference from the above embodiment is that in the above embodiment, as shown in FIG. 5A, when the inspection area 401 of the thermally-assisted magnetic head element portion 501 is scanned with the cantilever 10, the cantilever 10 is moved in the X direction and the −X direction. However, in another embodiment, as shown in FIG. 5B, scanning is performed by the cantilever 10 in the Y direction and the −Y direction.

  When the Y stage 105 is moved while vibrating the cantilever 10 up and down in the inspection area 401, the probe 4 is scanned in the Y direction along the dotted line 1602 from the upper side to the lower side of the figure (thermal assist head element). 501 is moved downward with respect to the vertical direction in FIG. 4A), a magnetic field is generated from the write magnetic field generation unit 502 of the heat-assisted magnetic head element unit 501, and the cantilever 10 is driven in the MFM mode. , Detect the generated magnetic field. During the inspection in the MFM mode, the laser output from the laser driver 531 to the near-field light emitting unit 504 is stopped.

  On the other hand, when the Y stage 105 is scanned from the lower side to the upper side along the dotted line 1603 in the Y direction (the thermal assist head element 501 is moved upward with respect to the direction perpendicular to the paper surface of FIG. 4B), The cantilever 10 is driven in the AFM mode without generating a magnetic field from the write magnetic field generation unit 502 of the heat-assisted magnetic head element unit 501 to measure the uneven shape on the surface of the inspection region 401 and near-field light emission from the laser driver 531. The laser is output to the unit 504 to generate near-field light from the near-field light generation unit 504 and detected by the near-field light detection optical system 115.

  As described above, during the inspection, the MFM mode inspection and the AFM mode inspection are switched depending on the scanning direction in the Y direction of the thermally-assisted magnetic head element unit 501 with respect to the cantilever 10, and near-field light emission is performed while the inspection is performed in the MFM mode. By stopping the application of the pulse driving current or the pulse driving voltage 5311 to the unit 504, it becomes possible to suppress the temperature rise of the heat-assisted magnetic head element unit 501 due to heat generation from the near-field light emitting unit 504, and heat Generation of damage in the assist magnetic head element portion 501 can be avoided.

  In the MFM mode and the AFM mode, the height of the probe 4 of the cantilever 10 with respect to the surface of the inspection region 401 of the thermally-assisted magnetic head element unit 501 is switched. That is, when inspecting in the AFM mode, the height of the probe 4 of the cantilever 10 with respect to the surface of the inspection area 401 of the thermally-assisted magnetic head element portion 501 corresponds to the head flying height Hf at the time of writing to the magnetic disk. Set to the height you want. On the other hand, in the MFM mode, the height of the probe 4 is set to be greater than Hf (the gap between the surface of the inspection region 401 and the tip of the probe 4 is increased). This height switching is performed by driving the Z stage 104 with a piezo driver 107.

  In the example shown in FIG. 5B as in the example shown in FIG. 5A, the adjacent dotted lines 1602 and 1603 are displayed so as to scan different positions in the Y direction, but the same position in the Y direction, That is, the dotted lines 1602 and 1603 may be scanned so as to overlap. In that case, first, the thermally assisted magnetic head element unit 501 is moved along the dotted line 1602 to perform the AFM mode inspection, and the thermally assisted magnetic head element unit 501 is moved in the reverse direction along the dotted line 1603 to perform the MFM. Check the mode. Next, the AFM mode inspection and the MFM mode inspection are performed by moving the heat-assisted magnetic head element portion 501 by one pitch in the X direction.

  The laser driver 531 applies a constant current or voltage instead of the pulse driving current or pulse driving voltage to generate the near field light 505 from the near field light generating unit 504 of the thermally assisted magnetic head element unit 501. It may be.

  As mentioned above, although the invention made by the present inventor has been specifically described based on the embodiments, it is needless to say that the present invention is not limited to the above embodiments and can be variously modified without departing from the gist thereof. Yes.

  DESCRIPTION OF SYMBOLS 1 ... Lever 4 ... Probe 10 ... Cantilever 30 ... Control part 40 ... Thermally assisted magnetic head element 100 ... Thermally assisted magnetic head element inspection apparatus 101 ... Inspection stage 104- ..Z stage 105 ... Y stage 106 ... X stage 107 ... piezo driver 111 ... differential amplifier 114 ... mounting section 115 ... near-field light detection optical system 130 ... Displacement detection unit 140 ... probe unit 210 ... near-field light detection optical system unit 220 ... observation optical system unit 230 ... optical system switching mechanism 510 ... imaging lens system 523 ... light detection 525... CCD camera 530... Near-field light detection control system 531... Laser driver 532 · Pulse modulator 533 ... control board 534 ... bias power supply 535 ... lock-in amplifier 536 ... control PC

Claims (6)

Scanning probe microscope means comprising an XY table mounted with a thermally assisted magnetic head element and movable in an XY plane, and a cantilever having a probe having a magnetic film formed on the tip thereof on the surface;
An alternating current is supplied to a terminal formed on the thermally assisted magnetic head element mounted on the XY table of the scanning probe microscope means, and a driving current is supplied to the near-field light emitting unit formed on the thermally assisted magnetic head element. Or a probe unit for applying a driving voltage;
An imaging means for imaging the thermally-assisted magnetic head element mounted on the XY table in a visual field;
Scattered light having a photodetector for detecting scattered light generated from the probe when the probe is in a near-field light generation region generated from a near-field light emitting unit formed in the thermally-assisted magnetic head element. Detection means;
An optical system switching means that mechanically switches between the arrangement of the imaging means and the arrangement of the scattered light detection means, and enables application of either one of the means;
The image picked up by the image pickup means is recognized, and the relative position between the near-field light emitting unit and the scattered light detection means is adjusted to an appropriate position for the scattered light detection means to detect the scattered light. Alignment means for
While the laser beam is stopped from the probe unit to the near-field light emitting unit, an alternating current is supplied to the terminal to generate a magnetic field on the surface of the thermally-assisted magnetic head element, and the surface is covered with the probe of the cantilever. In the state where the output signal output from the scanning probe microscope means and the supply of alternating current to the terminal are stopped, a laser is incident from the probe unit to the near-field light emitting unit in the proximity state. The heat-assisted magnetic head using an output signal output from the scattered light detection means by scanning the surface of the heat-assisted magnetic head element with the probe of the cantilever while generating near-field light from a field light emitting unit A heat-assisted magnetic head inspection apparatus comprising: signal processing means for inspecting an element. 2. The heat-assisted magnetic head inspection apparatus according to claim 1, wherein particles of a noble metal or an alloy containing a noble metal are formed on a magnetic film formed on a surface of the probe. Magnetic head inspection device. The heat-assisted magnetic head inspection apparatus according to claim 1 or 2, wherein the signal processing means processes an output signal from the scanning probe microscope means and an output signal from the scattered light detection means, An apparatus for inspecting a heat-assisted magnetic head, characterized in that a distribution of a magnetic field generated by the heat-assisted magnetic head element and a distribution of near-field light generated in the vicinity of the near-field light emitting unit are obtained. A thermally assisted magnetic head element is mounted on the XY table of a scanning probe microscope having a cantilever having a probe with a magnetic film formed on the surface at the tip and an XY table movable in the XY plane,
The thermally assisted magnetic head element is stored in a field of view and imaged by an imaging means,
The image picked up by the image pickup means is recognized, and the near-field light emitting part formed on the thermally-assisted magnetic head element and the scattered light detection are moved to an appropriate position for the scattered light detection means to detect the scattered light. Adjust the relative position with the means,
Supplying an alternating current to a terminal formed on the thermally-assisted magnetic head element mounted on the XY table to generate a magnetic field in the thermally-assisted magnetic head element;
Scanning the surface of the thermally-assisted magnetic head element with a probe of a cantilever of the scanning probe microscope in a state where a magnetic field is generated in the thermally-assisted magnetic head element, obtaining the distribution of the generated magnetic field,
By mechanically switching between the arrangement of the imaging means and the arrangement of the scattered light detection means, the scattered light detection means is applied,
A laser is incident on a near-field light emitting unit formed on a thermally-assisted magnetic head element mounted on the XY table to generate near-field light from the near-field light emitting unit,
The surface of the thermally-assisted magnetic head element is scanned with a probe of a cantilever of the scanning probe microscope in a state where near-field light is generated from the near-field light emitting unit, and the probe is generated in the near-field light generation region. The scattered light generated from the light is collected and detected by the scattered light detection means, and the emission region of the near-field light and its distribution are obtained from the detected scattered light,
A heat-assisted magnetic head inspection method, wherein the quality of the thermally-assisted magnetic head element is determined based on the obtained magnetic field distribution, the obtained near-field light emission region and the distribution information. 5. The thermally assisted magnetic head inspection method according to claim 4, wherein particles of a noble metal or an alloy containing a noble metal are formed on a magnetic film formed on a surface of the probe. When the portion is in the near-field light generated in the near-field light emitting portion, the scattered light amplified by the localized surface plasmon enhancement effect is generated by the particles of the noble metal or the alloy containing the noble metal. Thermally assisted magnetic head inspection method. 5. The thermally assisted magnetic head inspection method according to claim 4, wherein the probe scans the entire surface of the inspection region set on the thermally assisted magnetic head element once, thereby detecting a magnetic field in the inspection region. A heat-assisted magnetic head inspection method characterized by obtaining a distribution, a light emitting region of near-field light, and a distribution thereof.

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